1,051 research outputs found

    Palm yellows phytoplasmas and their genetic classification

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    Palm yellows phytoplasmas have been a subject of debate because of two recent outbreaks. Firstly, a lethal yellowing-type phytoplasma disease was recorded on a number of palm species of mainly the genus Phoenix in Florida in 2008. Shortly afterwards, Sabal palmetto which has never been threatened by a phytoplasma before, was suddenly attacked by a phytoplasma strain similar to the one that attacked Phoenix in 2008. Both these recent outbreaks have made phytoplasmologists realize the need to characterize palm phytoplasma strains in order to rapidly determine the phytoplasma palm yellows in future disease outbreaks. Various workers have made attempts to genetically characterize palm phytoplasmas but a lot of crucial knowledge is still lacking. This review focuses on the little progress that has been made to characterize palm phytoplasmas and we also recommend further steps to provide more tools for characterization.Keywords: Cocos nucifera, palm yellows phytoplasmas, Sabal palmetto, Phoenix.African Journal of Biotechnology Vol. 12(22), pp. 3376-338

    A Strategic Plan for Introducing, Implementing, Managing, and Monitoring an Urban Extension Platform

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    Florida\u27s Strategic Plan for Extension in Metropolitan Regions reflects an adaptive management approach to the state\u27s urban Extension mission within the context of establishing essential elements, performance indicators, key outcomes, and suggested alternatives for action. Extension leadership has adopted the strategic plan, and implementation efforts are under way. The successful future of urban Extension in Florida lies in fully embracing and monitoring the plan and recommendations therein. In this article, we describe the course of developing the strategic plan, which included the use of a modified Delphi process and a strategic adaptive management format. We encourage others to adapt our methods to develop plans to meet their specific needs and desired outcomes

    COVID-19 Stress and Child Behavior: Examining Discrimination and Social Support in Racially Diverse ECHO Cohorts

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    Objective To examine the additive or moderating influences of caregiver COVID-19–related stress, social support, and discrimination on children’s behavior problems across racially diverse populations. Method In this Environmental influences on Child Health Outcomes (ECHO) cohort study (N = 1,999 caregiver/child pairs), we operationalized caregiver COVID-19–related stress in 2 ways: first, as the number of stressors (eg, financial concerns, social distancing); and second, as the level of pandemic-related traumatic stress symptoms reported via questionnaires administered between April 2020 and August 2022. At the same assessment visit, caregivers also reported their current levels of discrimination, and a subsample (n = 968) reported their emotional and instrumental support. Either concurrently or at a later assessment visit, caregivers reported on their children’s internalizing and externalizing behavior problems using the Child Behavior Checklist for Ages 6-18 (CBCL/6-18). Results Multivariable analyses controlling for maternal education, marital status, child age, and child sex revealed that COVID-19–related stress (caregiver stressors and symptoms) and discrimination were positively associated, and that perceived support was negatively associated with child internalizing and externalizing behavior problems. Unexpectedly, neither emotional nor instrumental support attenuated the relationship between caregiver COVID-19–related stressors nor traumatic stress symptoms and child behavior problems. In the subset of Black American participants, caregiver perceived discrimination moderated the relationship between caregiver COVID-19 traumatic stress symptoms and child internalizing problems, such that the association was stronger at higher levels of discrimination. Conclusion Our findings highlight the potential importance of relieving caregiver stress and increasing caregiver social support to optimize children’s behavioral outcomes

    A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

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    Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to study the gamma-ray emission towards 13 globular clusters. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices (0.7<Γ<1.4)(0.7 < \Gamma <1.4) and clear evidence for an exponential cut-off in the range 1.0-2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices (1.0<Γ<1.7)(1.0 < \Gamma < 1.7), however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600-4700 MSPs in Galactic globular clusters, commensurate with previous estimates. The observation of high-energy gamma-ray emission from a globular cluster thus provides a reliable independent method to assess their millisecond pulsar populations that can be used to make constraints on the original neutron star X-ray binary population, essential for understanding the importance of binary systems in slowing the inevitable core collapse of globular clusters.Comment: Accepted for publication in A&A. Corresponding authors: J. Kn\"odlseder, N. Webb, B. Pancraz

    Measurement Bias in Caregiver-Report of Early Childhood Behavior Problems across Demographic Factors in an Echo-Wide Diverse Sample

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    BACKGROUND: Research and clinical practice rely heavily on caregiver-report measures, such as the Child Behavior Checklist 1.5-5 (CBCL/1.5-5), to gather information about early childhood behavior problems and to screen for child psychopathology. While studies have shown that demographic variables influence caregiver ratings of behavior problems, the extent to which the CBCL/1.5-5 functions equivalently at the item level across diverse samples is unknown. METHODS: Item-level data of CBCL/1.5-5 from a large sample of young children ( RESULTS: Items with the most impactful DIF across child and caregiver groupings were identified for Internalizing, Externalizing, and total Problems. The robust item sets, excluding the high DIF items, showed good reliability and high correlation with the original Internalizing and total Problems scales, with lower reliability for Externalizing. Language version of CBCL administration, education level and sex of the caregiver respondent showed the most significant impact on MI, followed by child age. Sensitivity analyses revealed that child race has a unique impact on DIF over and above socioeconomic status. CONCLUSIONS: The CBCL/1.5-5, a caregiver-report measure of early childhood behavior problems, showed bias across demographic groups. Robust item sets with less DIF can measure Internalizing and total Problems equally as well as the full item sets, with slightly lower reliability for Externalizing, and can be crosswalked to the metric of the full item set, enabling calculation of normed T scores based on more robust item sets

    Maternal Education Prospectively Predicts Child Neurocognitive Function: An Environmental Influences on Child Health Outcomes Study

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    A large body of research has established a relation between maternal education and children's neurocognitive functions, such as executive function and language. However, most studies have focused on early childhood and relatively few studies have examined associations with changes in maternal education over time. Consequently, it remains unclear if early maternal education is longitudinally related to neurocognitive functions in children, adolescents, and young adults. In addition, the associations between changes in maternal education across development and more broadly defined neurocognitive outcomes remain relatively untested. The current study leveraged a large multicohort sample to examine the longitudinal relations between perinatal maternal education and changes in maternal education during development with children's, adolescents', and young adults' neurocognitive functions (N = 2,688; Mage = 10.32 years; SDage = 4.26; range = 3-20 years). Moreover, we examined the differential effects of perinatal maternal education and changes in maternal education across development on executive function and language performance. Perinatal maternal education was positively associated with children's later overall neurocognitive function. This longitudinal relation was stronger for language than executive function. In addition, increases in maternal education were related to improved language performance but were not associated with executive functioning performance. Our findings support perinatal maternal education as an important predictor of neurocognitive outcomes later in development. Moreover, our results suggest that examining how maternal education changes across development can provide important insights that can help inform policies and interventions designed to foster neurocognitive development. (PsycInfo Database Record (c) 2024 APA, all rights reserved)

    Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

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    The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye
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