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Seed retention, and ultimately seed shatter, are extremely important for the efficacy of harvest weed seed control (HWSC) and are likely influenced by various agroecological and environmental factors. Field studies investigated seed-shattering phenology of 22 weed species across three soybean [Glycine max (L.) Merr.]-producing regions in the United States. We further evaluated the potential drivers of seed shatter in terms of weather conditions, growing degree days, and plant biomass. Based on the results, weather conditions had no consistent impact on weed seed shatter. However, there was a positive correlation between individual weed plant biomass and delayed weed seed–shattering rates during harvest. This work demonstrates that HWSC can potentially reduce weed seedbank inputs of plants that have escaped early-season management practices and retained seed through harvest. However, smaller individuals of plants within the same population that shatter seed before harvest pose a risk of escaping early-season management and HWSC.
High-quality diets have been found to be beneficial in preventing long-term weight gain. However, concurrent changes in diet quality and body weight over time have rarely been reported. We examined the association between 10-year changes in diet quality and body weight in the Multiethnic Cohort Study. Analyses included 53 977 African Americans, Native Hawaiians, Japanese Americans, Latinos and Whites, who completed both baseline (1993–1996, 45–69 years) and 10-year follow-up (2003–2008) surveys including a FFQ and had no history of heart disease or cancer. Using multivariable regression, weight changes were regressed on changes in four diet quality indexes, Healthy Eating Index-2015, Alternative Healthy Eating Index-2010, alternate Mediterranean Diet and Dietary Approaches to Stop Hypertension scores. Mean weight change over 10 years was 1·2 (sd 6·8) kg in men and 1·5 (sd 7·2) kg in women. Compared with stable diet quality (< 0·5 sd change), the greatest increase (≥ 1 sd increase) in the diet scores was associated with less weight gain (by 0·55–1·17 kg in men and 0·62–1·31 kg in women). Smaller weight gain with improvement in diet quality was found in most subgroups by race/ethnicity, baseline age and baseline BMI. The inverse association was stronger in younger age and higher BMI groups. Ten-year improvement in diet quality was associated with a smaller weight gain, which varied by race/ethnicity and baseline age and BMI. Our findings suggest that maintaining a high-quality diet and improving diet quality over time may prevent excessive weight gain.
Influenza vaccine effectiveness (VE) wanes over the course of a temperate climate winter season but little data are available from tropical countries with year-round influenza virus activity. In Singapore, a retrospective cohort study of adults vaccinated from 2013 to 2017 was conducted. Influenza vaccine failure was defined as hospital admission with polymerase chain reaction-confirmed influenza infection 2–49 weeks after vaccination. Relative VE was calculated by splitting the follow-up period into 8-week episodes (Lexis expansion) and the odds of influenza infection in the first 8-week period after vaccination (weeks 2–9) compared with subsequent 8-week periods using multivariable logistic regression adjusting for patient factors and influenza virus activity. Records of 19 298 influenza vaccinations were analysed with 617 (3.2%) influenza infections. Relative VE was stable for the first 26 weeks post-vaccination, but then declined for all three influenza types/subtypes to 69% at weeks 42–49 (95% confidence interval (CI) 52–92%, P = 0.011). VE declined fastest in older adults, in individuals with chronic pulmonary disease and in those who had been previously vaccinated within the last 2 years. Vaccine failure was significantly associated with a change in recommended vaccine strains between vaccination and observation period (adjusted odds ratio 1.26, 95% CI 1.06–1.50, P = 0.010).
Potential effectiveness of harvest weed seed control (HWSC) systems depends upon seed shatter of the target weed species at crop maturity, enabling its collection and processing at crop harvest. However, seed retention likely is influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed-shatter phenology in 13 economically important broadleaf weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to 4 wk after physiological maturity at multiple sites spread across 14 states in the southern, northern, and mid-Atlantic United States. Greater proportions of seeds were retained by weeds in southern latitudes and shatter rate increased at northern latitudes. Amaranthus spp. seed shatter was low (0% to 2%), whereas shatter varied widely in common ragweed (Ambrosia artemisiifolia L.) (2% to 90%) over the weeks following soybean physiological maturity. Overall, the broadleaf species studied shattered less than 10% of their seeds by soybean harvest. Our results suggest that some of the broadleaf species with greater seed retention rates in the weeks following soybean physiological maturity may be good candidates for HWSC.
Seed shatter is an important weediness trait on which the efficacy of harvest weed seed control (HWSC) depends. The level of seed shatter in a species is likely influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter of eight economically important grass weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to 4 wk after maturity at multiple sites spread across 11 states in the southern, northern, and mid-Atlantic United States. From soybean maturity to 4 wk after maturity, cumulative percent seed shatter was lowest in the southern U.S. regions and increased moving north through the states. At soybean maturity, the percent of seed shatter ranged from 1% to 70%. That range had shifted to 5% to 100% (mean: 42%) by 25 d after soybean maturity. There were considerable differences in seed-shatter onset and rate of progression between sites and years in some species that could impact their susceptibility to HWSC. Our results suggest that many summer annual grass species are likely not ideal candidates for HWSC, although HWSC could substantially reduce their seed output during certain years.
Vertebrates may be born highly dependent (altricial) or may rapidly gain independence (precocial). Primates are generally considered somatically precocial. However, all are at least initially helpless, and many primates have a prolonged phase of juvenility. In this chapter, we discuss how selection may influence the relative timing of appearance of morphological features (heterochrony). Newborn primate morphology offers unique insights into the roles of prenatal and postnatal growth processes, primarily because metabolic costs for growth commence a transition from the mother to the infant at this point in time. With this in mind, primates vary remarkably at birth in dental eruption and mineralization status as well as limb skeleton ossification (e.g., wrists and ankles). We also discuss evidence, still relatively scant, that at birth primates vary greatly in the degree to which neural organs (e.g., brains, eyes) have achieved adult size and proportions. In preparation for morphological descriptions to follow, the reader is introduced to the concept of modularity of growth: different parts of the skeleton or even parts of regions have different rates of growth and development.
Skeletal Anatomy of the Newborn Primate was written to broaden our knowledge of non-human primates from a comparative and developmental perspective. This chapter explains that the main focus of our book is on the inherently risky neonatal period. The “neonate,” or newborn, is considered here to be a perinatal primate of up to seven days postnatal age. However, there is no simple way to physically identify primate newborns, not in the same many have defined “infants,” based on dental maturity. This is precisely what makes the neonatal stage so interesting: primates, like most other groups of mammals, vary in how rapidly they attain physical maturity. This introductory chapter discusses terminology and methodological challenges in studying newborns.
Feeding ontogeny in primates has three stages. In utero, nutrition is gained maternally. After birth, primates suckle. We know little about functional variation in these stages. The transition to adult feeding – highlighted by weaning – varies across species. Variation is tied to many socioecological and morphological influences across primates. Primate feeding apparatus ontogeny is affected by many factors. Diet exhibits a complex relationship with the clearest signal marked by rapid dental mineralization and eruption in folivorous strepsirrhines. Mineralization varies across primates. Emergence and eruption of postcanine teeth tends to follow size in both suborders with smaller taxa showing earlier emergence, the exception being rapid eruption in some folivores. Compared to teeth, less is known about the musculoskeletal ontogeny of the feeding apparatus. Most studies compare closely related species and link musculoskeletal robustness to challenging diets. Looking forward, better understanding of primate feeding apparatus growth will require improved samples (a challenge for long-lived species) and emphasis on the evolutionary significance of feeding throughout ontogeny.
In this chapter we introduce concepts in dental development, microanatomy of the tooth germ and mineralizing crowns, and terminology relating to dental morphology. Subsequently, tooth morphology in newborn hominoids (apes and humans) is discussed based on the literature, followed by accounts of the extent of crown mineralization at birth in a newly described sample of tarsiers, Old World monkeys, New World monkeys, and strepsirrhines (lemurs and lorises). Morphology of crowns is described in all species in which the crown is completely formed at birth. The chapter ends with a brief discussion of the “perinatal” trajectory of dental development in selected primate species based on a comparison of species at different stages (fetal, neonatal, and older infant), including some at similar known ages.
Life-history theory pertains to the entirety of prenatal and postnatal ontogeny, and therefore morphology of the newborn offers an important perspective on how primates invest in their young. Generally, longer gestations yield larger neonates that are weaned later, become sexually mature later, and have larger brain masses. But can the variations in skeletal maturity are birth explained by life-history traits? Here, we examine new somatic data on 47 species of primates in light of life-history traits and modularity of growth among body regions. “Snout” length is uniformly diminutive in newborns compared to adults, although some scaling differences are already apparent at birth (relatively longer palates in strepsirrhines and tarsiers). Correlations of life-history characteristics indicate gestational length has a significant influence on facial functional matrices, with a positive correlation with permanent tooth and eye size, and a negative correlation with deciduous tooth germ size. We may as yet lack a broad enough perspective on brain size at birth, but some existing observations suggest primates preferentially prioritize prenatal brain growth over general somatic growth.
Primate locomotor development is a protracted process. We summarize the time course of locomotor development in approximately 50 primates distributed across the extant radiation. Despite substantial variance, we identify several broad trends. Primates are somewhat precocial at birth – born with their eyes open and able to strongly grasp. Locomotor onset age generally increases with body mass, although certain taxonomic groups (e.g., lemurids and cercopithecids) develop early for their size whereas others (e.g., indriids and hominids) develop relatively late. Initial locomotor movements are similar across primates and dominated by quadrupedal crawling. Only later do more specialized forms of locomotion emerge (e.g., leaping and brachiation), often in concert with functional changes in musculoskeletal anatomy (e.g., maturation of intermembral indices, center of mass position, and bony muscle leverage). We advocate viewing locomotor development as a fundamental life-history parameter, responding to the same evolutionary pressures shown to be fundamental to other aspects of primate life history (e.g., predation, resource access, body size, encephalization).
In this chapter we discuss the vertebral column, ribs, and sternum from a developmental perspective. The axial skeleton of newborn hominoids (apes and humans) is discussed based on the literature, followed by accounts of osteology in a newly described sample of newborn tarsiers, Old World monkeys, New World monkeys, and strepsirrhines (lemurs and lorises). The neonatal vertebral column is fragmented in skeletonized specimens, because in most vertebrae, actively growing synchondroses connect the right and left neural arches and connect the centrum to the arches. Transverse processes, portions of the articular facets, and the ventral arch of C1 are also cartilaginous in most primates. However, tarsiers and most monkeys have an ossified C1 ventral arch. The chapter ends with a brief discussion of the early postnatal trajectory of axial skeleton ossification in selected primate species based on a comparison of species at different stages (neonatal and older infant), including some at similar known ages.
Birth represents a transitional point in time – a static moment that borders a time of complete dependency and the march toward independence. This chapter reviews some basic concepts of vertebrate development and histology. Of particular relevance are tissue changes that reflect differentiation of mineralized tissues: skeletogenesis and odontogenesis, beginning with changes to the primitive connective tissue (mesenchyme). Viewed by microscopy, mesenchyme condenses prior to differentiation into cartilage, bone or tooth germs. Most mesenchymal condensations for the skeleton form during the embryonic period, but they continue to appear during the fetal period or postnatally for some structures (e.g., successional teeth). Most growth of the skeleton occurs during the fetal and postnatal periods. Mineralized connective tissues have different available growth processes. The contributions of appositional growth (new matrix is added to existing matrix), interstitial growth (cell replication and matrix production within existing tissue), and bone modeling (selective osteoclastic and osteoblastic activity) are discussed according to types of bones and skeletal regions.