50 research outputs found

    Stay-green traits to improve wheat adaptation in well-watered and water-limited environments

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    A stay-green phenotype enables crops to retain green leaves longer after anthesis compared with senescent types, potentially improving yield. Measuring the normalized difference vegetative index (NDVI) during the whole senescence period allows quantification of component stay-green traits contributing to a stay-green phenotype. These objective and standardized traits can be compared across genotypes and environments. Traits examined include maximum NDVI near anthesis (Nmax), senescence rate (SR), a trait integrating senescence (SGint), plus time from anthesis to onset (OnS), mid-point (MidS), and near completion (EndS) of senescence. The correlation between stay-green traits and yield was studied in eight contrasting environments ranging from well watered to severely water limited. Environments were each classified into one of the four major drought environment types (ETs) previously identified for the Australian wheat cropping system. SGint, OnS, and MidS tended to have higher values in higher yielding environments for a given genotype, as well as for higher yielding genotypes within a given environment. Correlation between specific stay-green traits and yield varied with ET. In the studied population, SGint, OnS, and MidS strongly correlated with yield in three of the four ETs which included well-watered environments (0.43–0.86), but less so in environments with only moderate water-stress after anthesis (−0.03 to 0.31). In contrast, Nmax was most highly correlated with yield under moderate post-anthesis water stress (0.31–0.43). Selection for particular stay-green traits, combinations of traits, and/or molecular markers associated with the traits could enhance genetic progress toward stay-green wheats with higher, more stable yield in both well-watered and water-limited conditions

    Drought adaptation of stay-green sorghum is associated with canopy development, leaf anatomy, root growth, and water uptake

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    Stay-green sorghum plants exhibit greener leaves and stems during the grain-filling period under water-limited conditions compared with their senescent counterparts, resulting in increased grain yield, grain mass, and lodging resistance. Stay-green has been mapped to a number of key chromosomal regions, including Stg1, Stg2, Stg3, and Stg4, but the functions of these individual quantitative trait loci (QTLs) remain unclear. The objective of this study was to show how positive effects of Stg QTLs on grain yield under drought can be explained as emergent consequences of their effects on temporal and spatial water-use patterns that result from changes in leaf-area dynamics. A set of four Stg near-isogenic lines (NILs) and their recurrent parent were grown in a range of field and semicontrolled experiments in southeast Queensland, Australia. These studies showed that the four Stg QTLs regulate canopy size by: (1) reducing tillering via increased size of lower leaves, (2) constraining the size of the upper leaves; and (3) in some cases, decreasing the number of leaves per culm. In addition, they variously affect leaf anatomy and root growth. The multiple pathways by which Stg QTLs modulate canopy development can result in considerable developmental plasticity. The reduction in canopy size associated with Stg QTLs reduced pre-flowering water demand, thereby increasing water availability during grain filling and, ultimately, grain yield. The generic physiological mechanisms underlying the stay-green trait suggest that similar Stg QTLs could enhance post-anthesis drought adaptation in other major cereals such as maize, wheat, and rice

    Drought adaptation of stay-green sorghum is associated with canopy development, leaf anatomy, root growth, and water uptake

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    Stay-green sorghum plants exhibit greener leaves and stems during the grain-filling period under water-limited conditions compared with their senescent counterparts, resulting in increased grain yield, grain mass, and lodging resistance. Stay-green has been mapped to a number of key chromosomal regions, including Stg1, Stg2, Stg3, and Stg4, but the functions of these individual quantitative trait loci (QTLs) remain unclear. The objective of this study was to show how positive effects of Stg QTLs on grain yield under drought can be explained as emergent consequences of their effects on temporal and spatial water-use patterns that result from changes in leaf-area dynamics. A set of four Stg near-isogenic lines (NILs) and their recurrent parent were grown in a range of field and semicontrolled experiments in southeast Queensland, Australia. These studies showed that the four Stg QTLs regulate canopy size by: (1) reducing tillering via increased size of lower leaves, (2) constraining the size of the upper leaves; and (3) in some cases, decreasing the number of leaves per culm. In addition, they variously affect leaf anatomy and root growth. The multiple pathways by which Stg QTLs modulate canopy development can result in considerable developmental plasticity. The reduction in canopy size associated with Stg QTLs reduced pre-flowering water demand, thereby increasing water availability during grain filling and, ultimately, grain yield. The generic physiological mechanisms underlying the stay-green trait suggest that similar Stg QTLs could enhance post-anthesis drought adaptation in other major cereals such as maize, wheat, and rice

    Fear and loathing in the Caribbean: three studies of fear and cancer screening in Brooklyn's immigrant Caribbean subpopulations

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    Background: Anxiety, worry, and fear are among the most common emotional responses to the threat of disease and several studies have linked various fears to cancer preventive and detection behaviors. Cancer-related worry and fears about screening or its consequences are also characteristics that vary across ethnic groups and may be differentially linked to screening outcomes 1. Limiting the utility of this growing literature are at least two key considerations. First, little attention has been paid to documenting variation in cancer-related fears among subpopulations of persons of African descent, despite evidence that (a) rates of screening may vary among both male 2 and female 3 immigrants from islands in the Caribbean living in the United States and (b) incidence rates for cancers such as those of the prostate may be very high in men from Jamaica 4, Guadaloupe 5 and Trinidad and Tobago 6, as well as in immigrant groups in both the United Kingdom 7 and United States 8. Second, findings regarding the relations anxiety, cancer worry, and screening fear hold with screening behavior seen thus far have been inconsistent, in our view because anxieties stemming from different sources have different relations with behavior. In the emotions theory view, understanding the role of fear in health behavior in diverse groups is predicated on understanding the object or source of the fear 91011 for the simple reason that anxiety motivates avoidance of particular elicitors 1012. Research conducted within the U54 Comprehensive Cancer Partnership between Long Island University and Columbia University has produced several studies documenting differences in breast and prostate cancer screening frequencies among Caribbean subpopulations living in Brooklyn, New York 11213. A major concentration in this program of behavioral research has investigated whether trait anxiety, cancer worry, and screening-related fears vary across Caribbean subpopulations and whether these highly differentiated emotional responses independently predict screening behavior in multivariate models 12121314. Consistent with theory, we expected that fears pertaining to the screening context (e.g., fear of pain or the psychological implications of certain screens), would predict avoidance of the fear-inducing situation and thus be associated with less frequent screening. Conversely, where fears relate to the disease itself, greater fear should predict more frequent screening. Methods: Because of our overarching interest in the links between cancer and cancer-screening-related fears and cancer screening behaviors among the diverse groups of men and women living in Brooklyn, New York, we combined data from three community-based studies. Although measures and samples varied somewhat across studies, each study investigated the link between emotions and screening outcome in ethnic groups that included immigrants from islands in the Caribbean. Because of our interest in examining differences within traditional racial categories, we used a combination of (a) self-categorization based on a the traditional racial categories offered in the US Census together with (b) information regarding country of origin. Allowing a combination of self-reported racial categorization (tapping aspects of identity and minority status) in concert with shared birthplace to influence groupings increases the likelihood that participants share cultural and developmental characteristics thought to form part of ethnicity 15. We distinguished between Black men born in the United States (hereafter, U.S.-born African Americans), and those originating from countries in the English-speaking Caribbean (e.g., Trinidad & Tobago, Jamaica, Barbados). Immigrant and non-immigrant minority groups were contrasted with men self-identifying as "European or White/Non-Hispanic" who were born in the United States (hereafter, U.S.-born European American). In Study 1, stratified cluster-sampling was used to recruit 1364 women (aged between 50–70 years) from six ethnic groups: US-born African American, US-born European American, immigrants from islands in the English-speaking Caribbean (Jamaica, Barbados, Trinidad and Tobago), the Dominican Republic, Haiti, and Eastern Europe 1. In Study 2, 180 US-born African American, US-born European American and immigrant Jamaican men (aged between 40–70 years) were recruited using convenience sampling 13. In Study 3, 533 men (aged between 45–70 years) from four groups – US-born African American, US-born European American, and immigrant men from Jamaica and from Trinidad and Tobago – were recruited 12. In each study, participants provided background data, reported on screening history for either breast or prostate cancer, and completed a measure of trait anxiety, cancer worry, and/or screening fears. Results: As expected, we found differences among groups of African descent from the United States and the Caribbean. Although women from all groups screened at rates below those recommended, data from Study 1 showed that English-speaking Caribbean, Haitian and Dominican women screened less frequently than US-born African Americans and European Americans and that immigrant Eastern European women were also infrequent screeners (see Figure 1). Conversely, however, there were no differences in rates of self-reported prostate screening among men from the English-speaking Caribbean, US-born African Americans, or US-born European Americans in either Study 2 or Study 3. As expected, cancer-related emotional characteristics also varied across subpopulations (see Figure 2). Cancer worry was generally lower among women from the various Caribbean immigrant groups (Study 1) than it was among US-born African Americans or US-born European Americans. Fears regarding screening, however, varied somewhat differently. Fear of screening was higher among US-born African Americans and immigrant men from the English-speaking Caribbean (Studies 2 and 3) than among US-born European Americans. Consistent with the need to carefully measure fear-related constructs in the context of cancer behavior, however, our data also demonstrated that a specific fear related to concerns regarding threats to masculinity in the context of male screening strongly characterized the attitudes of men from the English-speaking Caribbean compared to the views of US-born European and US-born African Americans (Study 2). Finally, a combination of multiple regression and ANOVAs in each study showed that emotional characteristics independently predicted screening, in most cases even when background characteristics were controlled. Across studies, greater cancer worry predicted more frequent screening while fear of screening predicted less frequent screening. Figure 1 Number of cancer screens in prior 10 years Number of cancer screens in prior 10 years. DRE = digital rectal examination, PSA = prostate specific antigen test, Mamm = mammogram, CBE = clinical breast exam. Figure 2 Emotion characteristics related to screening Emotion characteristics related to screening. Trait = trait anxiety, Worry = cancer worry, Scr. Fr. = screening fear, and Em. Con. = emasculation concern. Conclusion: Data from three large-scale studies in Brooklyn, New York suggest that members of immigrant Caribbean subpopulations screen for breast and prostate cancer at very low rates; in most cases lower than those of either US-born African or US-born European Americans. Groups of Caribbean men and women also vary in the emotions they report regarding cancer and the screening process, generally revealing a pattern that is predictive of poorer screening. Coupled with the fact that emotion characteristics predicted screening outcomes even when controlling for other factors, data from these three studies suggest that the emotional responses Caribbean groups place them at risk for poor screening. Interventions that address these responses may offer the prospect of improving screening frequency in these disadvantaged groups. Competing interests: The authors declare that they have no competing interests. Authors' contributions: NSC and CM was involved in study design, analysis, interpretation/write up and critical revision of the manuscript. BA and DH in the analysis, interpretation and write up. AKJ, TU and LNB were involved in the interpretation and write up. PMR was part of the study design, analysis and interpretation/write up. JMM and AIN had part in the study design, analysis and critical revision whilst JSJ took part in critical revision

    A global perspective on the trophic geography of sharks

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    Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.This research was conducted as part of C.S.B.’s Ph.D dissertation, which was funded by the University of Southampton and NERC (NE/L50161X/1), and through a NERC Grant-in-Kind from the Life Sciences Mass Spectrometry Facility (LSMSF; EK267-03/16). We thank A. Bates, D. Sims, F. Neat, R. McGill and J. Newton for their analytical contributions and comments on the manuscripts.Peer reviewe

    Less Than a state, more than an international organization: The Sui generis nature of the European Union

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    In this paper, I show that the European Union (EU) is less than a state, but more than an international organization. Although it possesses some characteristics of both, the European Union is, I argue, a sui generis project: Although the EU wields extensive influence in some policy areas (such as competition policy or international trade regulation), its institutions’ powers are quite limited in many areas that remain firmly within the grasp of its Member States’ governments (such as security, justice, tax or redistribution policies). The European Union’s supranational elements – especially the EU laws’ supremacy over the laws of individual Member States – distinguish it, furthermore, from international organizations, such as the United Nations or the World Trade Organization. I conclude that the European Union is really a sui generis project that has not been attempted anywhere else: As such, it could be regarded as a useful case study, or perhaps even a “pilot project,” for regional integration projects elsewhere

    Hippocampal pyramidal cells: the reemergence of cortical lamination

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    The increasing resolution of tract-tracing studies has led to the definition of segments along the transverse axis of the hippocampal pyramidal cell layer, which may represent functionally defined elements. This review will summarize evidence for a morphological and functional differentiation of pyramidal cells along the radial (deep to superficial) axis of the cell layer. In many species, deep and superficial sublayers can be identified histologically throughout large parts of the septotemporal extent of the hippocampus. Neurons in these sublayers are generated during different periods of development. During development, deep and superficial cells express genes (Sox5, SatB2) that also specify the phenotypes of superficial and deep cells in the neocortex. Deep and superficial cells differ neurochemically (e.g. calbindin and zinc) and in their adult gene expression patterns. These markers also distinguish sublayers in the septal hippocampus, where they are not readily apparent histologically in rat or mouse. Deep and superficial pyramidal cells differ in septal, striatal, and neocortical efferent connections. Distributions of deep and superficial pyramidal cell dendrites and studies in reeler or sparsely GFP-expressing mice indicate that this also applies to afferent pathways. Histological, neurochemical, and connective differences between deep and superficial neurons may correlate with (patho-) physiological phenomena specific to pyramidal cells at different radial locations. We feel that an appreciation of radial subdivisions in the pyramidal cell layer reminiscent of lamination in other cortical areas may be critical in the interpretation of studies of hippocampal anatomy and function

    Prevalence of Age-Related Macular Degeneration in Europe: The Past and the Future

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    Purpose Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in Europe from 1990 to 2013 using the European Eye Epidemiology (E3) consortium, and made projections for the future. Design Meta-analysis of prevalence data. Participants A total of 42 080 individuals 40 years of age and older participating in 14 population-based cohorts from 10 countries in Europe. Methods AMD was diagnosed based on fundus photographs using the Rotterdam Classification. Prevalence of early and late AMD was calculated using random-effects meta-analysis stratified for age, birth cohort, gender, geographic region, and time period of the study. Best-corrected visual acuity (BCVA) was compared between late AMD subtypes; geographic atrophy (GA) and choroidal neovascularization (CNV). Main Outcome Measures Prevalence of early and late AMD, BCVA, and number of AMD cases. Results Prevalence of early AMD increased from 3.5% (95% confidence interval [CI] 2.1%–5.0%) in those aged 55–59 years to 17.6% (95%

    Improving efficiency of water use in rice-based cropping systems using permanent raised beds

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    A major challenge for the next 20 years is to develop genetic and agronomic solutions to combat water shortages for rice production and to develop ecosystems that better match crop growth with water supply. Experiments were conducted in northern Queensland, Australia (1989–1992) and eastern Indonesia (1993–1999) to develop a cropping system based on raised beds and saturated soil culture (SSC), whereby rice could successfully be grown in rotation with several field crops. Advantages of the SSC system include improved efficiencies of water use, energy savings, enhanced timeliness of field operations and reduced soil compaction. The northern Queensland studies indicated that double cropping rice and field crops on permanent raised beds provides additional synergistic and logistic benefits over those found in the traditional rice/fallow system. Subsequent experiments in West Timor found that various crops, as well as rice, can be grown on raised beds during the wet season, thus overcoming the problem of waterlogging. Moreover, if raised beds were constructed before the wet season in lowland areas, crops could be sown at the onset of the wet season, thus avoiding end-of-season drought and permitting significant increases in crop yields. Reforesting of eroded upland cropping areas with perennial tree species was also possible, provided the intensive lowland production met the subsistence farmers’ basic food and/or cash crop requirements. By increasing the probability of year-round crop production, this system, overall, can help enhance food security for South-East Asian subsistence farmers
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