144 research outputs found
Biological and integrated control of musk thistle in Missouri (2001)
"New 8/01/5M.""Integrated pest management.""The authors acknowledge the work of William Dierker (retired), Mahlon L. Fairchild (retired), James H. Jarman (University Outreach and Extension, Callaway County), and Richard McDonald (Symbiont, Sugar Grove, N.C.) in the development of this guide.""This publication replaces MU publication G4867, Integrated Control of Musk Thistle Using an Introduced Weevil.""Weed control.
An Ultrastructural and Fluorescent Study of the Teratocytes of Microctonus aethiopoides
The braconid wasp Microctonus aethiopoides Loan is an idiobiont endoparasitoid of alfalfa weevil adults Hypera postica (Gyllenhal). After oviposition and subsequent egg maturation, large trophic cells called teratocytes dissociate from the serosa and are released into the host hemocoel. These teratocytes are present in large numbers and are visible to the naked eye. It is thought that they accumulate host hemocoelic metabolites for later consumption by the parasitoid larvae. We have undertaken a microscopic study of these gargantuan and complex cells at approximately seven months after parasitization. Parasitized adult weevils were dissected into medium and teratocytes were fixed, embedded, and sectioned at 1 μm. Teratocytes were stained with various specific fluorescent dyes for plasma membrane, Golgi, nuclei, lysosomes, mitochondria, and endoplasmic reticulum (ER). The surface of each cell is covered with a dense microvillar layer. Analysis of fluorescent images showed that these cells do not have condensed nuclei. ER was abundant around the nuclear envelope. Lysosomes were positioned around the periphery of the nucleus and the Golgi apparatus was significantly enlarged, being located around the nuclear envelope
Really Underage Drinkers: Alcohol Use Among Elementary Students
Despite the current societal concern with underage drinking, little attention has been paid to alcohol use within the preadolescent population. This article presents the proceedings of a symposium held at the 2003 Research Society on Alcoholism meeting in Fort Lauderdale, Florida, that was organized and chaired by John E. Donovan. The intent of the symposium was to kick start research on alcohol use among elementary school children by reviewing what is known regarding drinking in childhood. Presentations included (1) The Epidemiology of Children's Alcohol Use, by John E. Donovan; (2) The Validity of Children's Self-Reports of Alcohol Use, by Sharon L. Leech; (3) Predicting Onset of Drinking From Behavior at Three Years of Age: Influence of Early Child Expectancies and Parental Alcohol Involvement Upon Early First Use, by Robert A. Zucker; and (4) Parent, Peer, and Child Risk Factors for Alcohol Use in Two Cohorts of Elementary School Children, by Carol J. Loveland-Cherry. Presentations indicated the need for better nationwide surveillance of children's experience with alcohol; suggested that children's reports of their use of alcohol tend to be reliable and valid; supported children's alcohol use schemas and parental drinking and alcoholism at child age three as independent predictors of early onset drinking; and showed that onset of drinking before fourth or fifth grade, peer pressure, and parental norms and monitoring predict elementary student alcohol use and misuse.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65944/1/01.ALC.0000113922.77569.4E.pd
Social Competence in Children of Alcoholic Parents Over Time.
In the current study, the authors tested the hypothesis that children of alcoholic parents (COAs) show deficits in social competence that begin in early childhood and escalate through middle adolescence. Teachers, parents, and children reported on the social competence of COAs and matched controls in a community sample assessed from ages 6 to 15. Hierarchical linear growth models revealed different patterns of change in social competence across development as a function of the reporter of various indicators of competence. Moreover, female COAs showed deficits in social competence in early childhood that receded in adolescence and that varied across subtypes of parent alcoholism. Implications of these findings for understanding the development of social competence in children, and at-risk children in particular, are discussed
Intraspecific variation and population structure of the Velvetbean Caterpillar, Anticarsia gemmatalis Hübner, 1818 (Insecta: Lepidoptera: Noctuidae)
Ontogeny and Season Constrain the Production of Herbivore-Inducible Plant Volatiles in the Field
Temperament Pathways to Childhood Disruptive Behavior and Adolescent Substance Abuse: Testing a Cascade Model
Abstract Temperament traits may increase risk for developmental
psychopathology like Attention-Deficit/Hyperactivity
Disorder (ADHD) and disruptive behaviors during childhood,
as well as predisposing to substance abuse during adolescence.
In the current study, a cascade model of trait pathways
to adolescent substance abuse was examined. Component
hypotheses were that (a) maladaptive traits would increase
risk for inattention/hyperactivity, (b) inattention/hyperactivity
would increase risk for disruptive behaviors, and (c) disruptive
behaviors would lead to adolescent substance abuse. Participants
were 674 children (486 boys) from 321 families in an
ongoing, longitudinal high risk study that began when
children were 3 years old. Temperament traits assessed were
reactive control, resiliency, and negative emotionality, using
examiner ratings on the California Q-Sort. Parent, teacher, and
self ratings of inattention/hyperactivity, disruptive behaviors,
and substance abuse were also obtained. Low levels of
childhood reactive control, but not resiliency or negative
emotionality, were associated with adolescent substance
abuse, mediated by disruptive behaviors. Using a cascade
model, family risk for substance abuse was partially mediated
by reactive control, inattention/hyperactivity, and disruptive
behavior. Some, but not all, temperament traits in childhood
were related to adolescent substance abuse; these effects were
mediated via inattentive/hyperactive and disruptive behaviors.This work was supported by NIAAA grant R01-AA12217 to Robert Zucker and Joel Nigg, NIAAA grant R37-AA07065 to Robert Zucker and Hiram Fitzgerald, and NIMH grant R01-MH59105 to Joel Nigg. Martel was supported by 1 F31 MH075533-01A2.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64507/1/#167, Martel 2009, Temperament path to disruptive behav and sub abuse JACP.pd
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Correspondence Between Perceived Pubertal Development and Hormone Levels in 9-10 Year-Olds From the Adolescent Brain Cognitive Development Study.
Aim: To examine individual variability between perceived physical features and hormones of pubertal maturation in 9-10-year-old children as a function of sociodemographic characteristics.
Methods: Cross-sectional metrics of puberty were utilized from the baseline assessment of the Adolescent Brain Cognitive Development (ABCD) Study—a multi-site sample of 9–10 year-olds (n = 11,875)—and included perceived physical features via the pubertal development scale (PDS) and child salivary hormone levels (dehydroepiandrosterone and testosterone in all, and estradiol in females). Multi-level models examined the relationships among sociodemographic measures, physical features, and hormone levels. A group factor analysis (GFA) was implemented to extract latent variables of pubertal maturation that integrated both measures of perceived physical features and hormone levels.
Results: PDS summary scores indicated more males (70%) than females (31%) were prepubertal. Perceived physical features and hormone levels were significantly associated with child\u27s weight status and income, such that more mature scores were observed among children that were overweight/obese or from households with low-income. Results from the GFA identified two latent factors that described individual differences in pubertal maturation among both females and males, with factor 1 driven by higher hormone levels, and factor 2 driven by perceived physical maturation. The correspondence between latent factor 1 scores (hormones) and latent factor 2 scores (perceived physical maturation) revealed synchronous and asynchronous relationships between hormones and concomitant physical features in this large young adolescent sample.
Conclusions: Sociodemographic measures were associated with both objective hormone and self-report physical measures of pubertal maturation in a large, diverse sample of 9-10 year-olds. The latent variables of pubertal maturation described a complex interplay between perceived physical changes and hormone levels that hallmark sexual maturation, which future studies can examine in relation to trajectories of brain maturation, risk/resilience to substance use, and other mental health outcomes
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