Early inherited risk for anxiety moderates the association between fathers' child-centered parenting and early social inhibition.

Studies of the role of the early environment in shaping children's risk for anxiety problems have produced mixed results. It is possible that inconsistencies in previous findings result from a lack of consideration of a putative role for inherited influences moderators on the impact of early experiences. Early inherited influences not only contribute to vulnerabilities for anxiety problems throughout the lifespan, but can also modulate the ways that the early environment impacts child outcomes. In the current study, we tested the effects of child-centered parenting behaviors on putative anxiety risk in young children who differed in levels of inherited vulnerability. We tested this using a parent-offspring adoption design and a sample in which risk for anxiety problems and parenting behaviors were assessed in both mothers and fathers. Inherited influences on anxiety problems were assessed as anxiety symptoms in biological parents. Child-centered parenting was observed in adoptive mothers and fathers when children were 9 months old. Social inhibition, an early temperament marker of anxiety risk, was observed at child ages 9 and 18 months. Inherited influences on anxiety problems moderated the link between paternal child-centered parenting during infancy and social inhibition in toddlerhood. For children whose birth parents reported high levels of anxiety symptoms, greater child-centered parenting in adoptive fathers was related to greater social inhibition 9 months later. For children whose birth parents reported low levels of anxiety symptoms, greater child-centered parenting in adoptive fathers was related to less social inhibition across the same period.

The relationship between parental depressive symptoms and offspring psychopathology: evidence from a children-of-twins study and an adoption study.

BACKGROUND: Parental depressive symptoms are associated with emotional and behavioural problems in offspring. However, genetically informative studies are needed to distinguish potential causal effects from genetic confounds, and longitudinal studies are required to distinguish parent-to-child effects from child-to-parent effects. METHOD: We conducted cross-sectional analyses on a sample of Swedish twins and their adolescent offspring (n = 876 twin families), and longitudinal analyses on a US sample of children adopted at birth, their adoptive parents, and their birth mothers (n = 361 adoptive families). Depressive symptoms were measured in parents, and externalizing and internalizing problems measured in offspring. Structural equation models were fitted to the data. RESULTS: Results of model fitting suggest that associations between parental depressive symptoms and offspring internalizing and externalizing problems remain after accounting for genes shared between parent and child. Genetic transmission was not evident in the twin study but was evident in the adoption study. In the longitudinal adoption study child-to-parent effects were evident. CONCLUSIONS: We interpret the results as demonstrating that associations between parental depressive symptoms and offspring emotional and behavioural problems are not solely attributable to shared genes, and that bidirectional effects may be present in intergenerational associations.

Analysis and influence of demographic and risk factors on difficult child behaviors.

This descriptive study examined the distribution of risk factors in a sample that was selected on the basis of existing potential for difficult child behaviors. We inquired into whether exposure to risk factors was distributed equally across different contexts of ethnicity, locality, and child gender. Participants included 731 mother-child dyads recruited from WIC Programs in rural, suburban, and urban localities. Cumulative risk indices were constructed using neighborhood, family, and individual risk factors. The findings generally revealed that African American children and children in urban localities were exposed to higher numbers of risk factors and cumulative risk in relation to other ethnic children and localities. On the other hand, Caucasian children expressed higher levels of vulnerabilities to risk for internalizing behaviors than did other children. The results are discussed in terms of differences in contextual specific rates of risk exposure, vulnerability, and their implications for prevention and intervention research.

Natural Occurrence of Phytophthora infestans on Black Nightshade (Solanum nigrum) in Wales.

There is only one published record of natural infection of black nightshade (Solanum nigrum L.) by Phytophthora infestans (Mont.) de Bary in England (3) and none from Wales. In August 2001, brown, necrotic leaf lesions with pale green margins were found on black nightshade weeds in a potato trial naturally infected with P. infestans at Henfaes Research Centre, University of Wales, Bangor. Although the plants were low growing with large, succulent leaves 4 to 5 cm long instead of having a more erect habit and smaller leaves, their identity was confirmed as S. nigrum; their atypical appearance may relate to the known phenotypic plasticity of this species (4). Infected leaflets incubated in moist chambers produced sporangia typical of P. infestans, and zoospores were released after chilling in water. Five isolates obtained from leaf fragments had growth on rye agar that was indistinguishable from that of P. infestans from potato. Detached leaflets of S. nigrum and S. tuberosum cv. Green Mountain inoculated with the S. nigrum isolates developed sporulating lesions under high humidity in 7 to 10 days; uninoculated controls remained symptomless. Inoculation of attached leaves of 10 potted S. nigrum plants resulted in seven plants developing necrotic lesions with a few sporangia 10 to 14 days later; sporulation developed mainly on lower leaves of plants that were older or had senesced. The remaining plants developed necrotic lesions with no sporulation, and P. infestans was reisolated from sporulating and nonsporulating lesions. All isolates were A1 mating type, metalaxyl-sensitive, and mitochondrial haplotype IIa, which are characteristics found commonly in isolates of P. infestans from potato in Wales (1). Single-sporangial isolates from each isolate were homozygous for glucose-6-phosphate isomerase and peptidase (Gpi 100/100, Pep 100/100). RG57 fingerprint analysis further established that all five black nightshade isolates were identical to each other and to some local P. infestans isolates from potato. P. infestans in Wales belongs to the new population (1), which may infect a wider host-range than the old US-1 clonal lineage. However, infected black nightshade was only found after late blight was widespread in potato fields. In subsequent years at the same site, weeds of S. nigrum have remained noninfected despite high levels of late blight pressure on adjacent potato plots. There is no evidence to suggest that this species acts as an overwintering host in Wales since it is an annual and lacks frost resistance. Field infection of S. nigrum by P. infestans has recently been reported in the Netherlands (2). Our observations confirm the potential of P. infestans to infect another solanaceous plant species. Alternative hosts may interfere with current disease control strategies because infected weeds would escape fungicide application and could serve as reservoirs of inoculum throughout the growing season. References: (1) J. P. Day and R. C. Shattock. Eur. J. Plant Pathol. 103:379, 1997. (2) W. G. Flier et al. Plant Pathol. 52:595, 2003. (3) J. M. Hirst and O. J. Steadman. Ann. Appl. Biol. 48:489, 1960. (4) B. S. Rogers and A. G. Ogg Jr. Page 30 in: Biology of Weeds of the Solanum Nigrum Complex (Solanum Section Solanum) in North America. USDA Publication ARM-W-23, 1981.

Variations in the Phytophthora infestans Population in Nepal as Revealed by Nuclear and Mitochondrial DNA Polymorphisms.

ABSTRACT Phytophthora infestans isolates collected from potato and tomato crops from various parts of Nepal during the 1999 and 2000 crop seasons were characterized for nuclear and mitochondrial DNA polymorphisms using restriction fragment length polymorphism markers. The nuclear DNA probe RG57 detected 11 multilocus genotypes among 280 isolates. Three genotypes were detected 21 times or more, constituting 94% of the total population, whereas frequencies of other genotypes ranged from 0.004 to 0.014. The overall genotypic diversity as estimated by the Gleason index was 1.78. Most of the overall diversity was present at the highest level (i.e., interregional, 46%), indicating limited gene flow among regions. Cluster analysis of multilocus genotypes derived from RG57 and mating type data for Nepalese isolates and representative isolates worldwide showed Nepalese isolates grouping into four clusters. Characterization of 67 isolates for mitochondrial DNA polymorphisms revealed the presence of two mt-haplotypes, Ia and Ib with the proportions of 0.88 and 0.12, respectively. Polymorphisms in nuclear and mitochondrial DNA revealed a moderate level of diversity in this population. Genotype NP3 had an identical RG57 fingerprint to US1 and had mt-haplotype Ib, confirming the presence of an old population in Nepal. Most of the genotypes had a different RG57 fingerprint than that of US1 and mt-haplotype Ia, the common characteristics of new populations. The presence of a new population at high proportions in Nepal was consistent with the global trend of mt-haplotype distribution, and suggests the displacement of old populations. This study indicates at least three possible introductions of P. infestans to Nepal.

A comparison of international silica (alpha-quartz) calibration standards by Fourier transform-infrared spectrophotometry.

Seven international silica (alpha-quartz) standards were examined for relative purity to the US National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1878 Respirable alpha-quartz by Fourier Transform-Infrared Spectrophotometry (FT-IR). The standards examined have been used in North America, the UK, Australia and Germany. The 189 samples analyzed included NIST-SRM 1878, Min-U-Sil 5, Ottawa Silica Sand, Sikron F-600, A9950 (AUST 1), DQ12-Robock, DQ12-Bergbau. Size distributions of the standards were determined by Coulter Counter to be broadly similar with equivalent spherical volume median diameter ranging between 1.2 and 3 microm. The results showed the standards to differ by as much as 30% in relative purity. Consequently, an internationally agreed upon calibration standard is urgently needed. Min-U-Sil 5 based NIST-SRM 1878 or Sikron F-600 are the two most likely candidates. Any agreed standard must have a well characterized size distribution and closely match the respirable dust criteria. It should also be studied by both infrared spectrophotometry and X-ray diffraction techniques.

Attachment stability and emotional and behavioral regulation from infancy to preschool age.

Relations between attachment and child emotional and behavioral regulation were studied longitudinally in a sample of 223 children from urban, low-income families. Attachment in the Strange Situation at 12 and 18 months was scored using the infant classification system and at 24 months was scored using a preschool classification system. Only modest stability was found in attachment whether within or across classification systems, with the percentage of insecure attachments consistently increasing over time. Results indicated both concurrent and predictive associations with indices of child regulation based on observer ratings or maternal report. However, only the 24-month classification predicted maternal report of externalizing and internalizing behavior problems at age 3.5 years. with additional variance accounted for by selected measures of child emotional and behavior regulation from the same assessment. Attachment security (B) and atypical attachment classifications (D, A/C, and AD) appear to provide the most consistently useful information about child functioning. Results are discussed in terms of continuity and change from the perspective of developmental psychopathology.

Intrafamily conflict in relation to boys' adjustment at school.

Several theoretical models of child development have posited the spread of conflict within families; however, few researchers have studied this process in association with relationships children have with teachers and peers at school. The present study examined the direct, additive, and interactive contributions of interparental, parent-child, and sibling conflict in relation to teacher-child and child-peer conflict in a sample of 117 low-income boys from ages 3.5 to 6 years. Overall, the results suggest that while conflict in any one dyadic family relationship is only modestly associated with later conflictual relationships at school, risk for conflict in relationships with teachers and peers increases when multiple forms of early family conflict are experienced. Results are discussed in terms of the development of conflict across early relationships.

Infant and toddler pathways leading to early externalizing disorders.

OBJECTIVE: To examine pathways leading to specific types of early externalizing disorders. METHOD: Longitudinal data were collected on 310 low-income, male subjects followed from infancy until age 6 years. RESULTS: Support across informants was found for the importance of the caregiving environment during infancy in relation to the development of externalizing disorders at school entry. Support was also found for the significance of early child factors, but this was limited to child behavior at home. CONCLUSIONS: The results are consistent with social learning and attachment models, which suggest that severe conduct problems in early childhood are the result of deficits in the caregiving environment. Support was also found for Moffitt's hypothesis that children with the comorbid attention-deficit/hyperactivity disorder-oppositional defiant disorder/conduct disorder pattern experience multiple child and psychosocial risk factors that begin during infancy.

Early externalizing behavior problems: toddlers and preschoolers at risk for later maladjustment.

The early emergence and developmental implications of externalizing behavior problems in toddlers and preschoolers are discussed with an emphasis on which young children are truly at risk for continuing problems. The extant literature is reviewed with a focus on the stability of early externalizing behavior and the diverse pathways that young children, primarily boys, with early-emerging problems may follow. Findings from a number of studies, both epidemiological and high risk, suggest that the small subgroup of boys with multiple risk factors that include especially high levels of early hyperactivity and aggression, and high levels of negative parenting and family stress, are most likely to evidence continuing problems at school entry. Sociodemographic and neighborhood influences are also discussed, as are implications for future research and policy.

Destructive sibling conflict and the development of conduct problems in young boys.

Little empirical work has explored the relation between destructive sibling conflict and conduct problems in children. This study used a measure of observed sibling conflict to examine its relations with maternal and teacher report of conduct problems in a low-income sample of 180 five-year-old boys and their close-age siblings. Early report of behavior problems and rejecting parenting were added to the analyses to control for these predictors and to examine interactive effects. The interaction between destructive sibling conflict and rejecting parenting predicted aggressive behavior problems across time and informants such that a rise in aggression scores was evident for children who had high levels of both sibling conflict and rejecting parenting. Sibling conflict was also directly related longitudinally to the Child Behavior Checklist Delinquency factor. Results are discussed in terms of additive risk models and G. R. Patterson's (1984, 1986) theory of coercion.

A truly early starter model of antisocial behavior revisited.

This paper revisits a developmental model of the origins of early conduct problems. Several of the model's primary tenets have now been validated in two samples of at-risk children followed prospectively from infancy to school-age. In both cohorts, child, family, and sociodemographic factors all play a significant role in the development of early conduct problems. In particular, the quality of the caregiving environment during the child's second year differentiates clinical impairment according to both parent and teacher report 6 years later. We conclude by making recommendations for future studies. Research that utilizes a developmental framework, incorporates more sophisticated measurement of infant negative emotionality, and addresses the influences of neighborhood and culture, is suggested.

Sprinkling irrigation enhances production of oospores of phytophthora infestans in field-grown crops of potato.

ABSTRACT Two field experiments were conducted to study the effect of overhead sprinkling irrigation on oospore formation by the late blight fungus Phytophthora infestans in potato. Total rain (natural + sprinkling) accumulated in treatments of experiment 1 (winter 1997 to 1998) were 765, 287, and 219 mm and treatments of experiment 2 (winter 1999 to 2000) were 641, 193, and 129 mm. Sporangia from 11 isolates of P. infestans were combined in eight pairs, seven of A1 and A2 and one of A2 and A2 mating type, and were sprayed on field-grown potato crops (42 plants per plot at 7 m(2) each) and examined for their ability to form oospores in the host tissues. In experiment 1, oospores were recorded in a total of 132 of 1,680 leaflets (7.9%), 24 of 105 stems, and 2 of 90 tubers. In experiment 2, oospores were recorded in 40 of 519 leaflets (7.7%), but not in any of the 90 stems or the 45 tubers examined. Both the proportion of leaflets containing oospores and the number of oospores per leaflet increased with time after inoculation and were dependent on the rain regime, the position of leaves on the plant, and the isolate pair combination. In both field trials, increasing the rainfall significantly enhanced oospore production in leaves. Leaf samples collected from the soil surface had significantly more oospores than those collected from the midcanopy. Two pairs in experiment 1 were more fertile than the others, whereas the pair used in experiment 2 was the least fertile. The total number of oospores per leaflet usually ranged from 10 to 100 in experiment 1, but only from 2 to 10 in experiment 2. Maximal oospore counts in the field were 200 and 50 in experiments 1 and 2, respectively, but ranged from approximately 2,000 to 12,000 oospores per leaflet in detached leaves in the laboratory. We concluded that P. infestans can produce oospores in the foliage of field-grown potato crops, especially when kept wet by regular overhead sprinkling irrigation, but production was far below that in the laboratory.

A longitudinal study of interparental conflict, emotional and behavioral reactivity, and preschoolers' adjustment problems among low-income families.

Researchers have begun to develop models that explain the processes by which interparental conflict impacts children's adjustment. The present study tested a model based on emotional security theory. The longitudinal relations among interparental conflict, boys' reactions to conflict, and internalizing and externalizing problems were examined in a sample of 129 mother-son dyads from low-income, 2-parent families from the time sons were age 2 to 5. Results indicated that children exposed to interparental conflict were more likely to have concurrent and later behavior problems and that patterns of interparental conflict across time made unique contributions in predicting later problems. Children's emotional reactivity in response to conflict had no direct relation to interparental conflict and only modest relations to behavior problems. However, interparental conflict and reactivity factors interacted to predict behavior problems at ages 3 1/2 and 5. Thus, some support was demonstrated for emotional reactivity as a moderator in the development of young children's behavior problems.

Individual traits and family contexts predict sons' externalizing behavior and preliminary relative risk ratios for conduct disorder and substance use disorder outcomes.

An ontogenetic framework for elucidating the etiology of substance use disorders (SUD) requires identifying how individual traits and family contexts combine to increase risk for SUD outcomes. In this study, we examine individual traits in family context to identify processes that account for the relationship between fathers' SUD + status and sons' externalizing behaviors. Results obtained from SUD + (n = 89) and SUD - (n = 139) families show that fathers' abusive propensities toward their sons mediated the relationship between fathers' SUD + status and sons' externalizing behavior scale (EBS) scores 2 years later. Moreover, individual traits, family contextual variables and deviant peer affiliations accounted for 58% of the variance on sons' EBS scores. Also, high risk cluster (HRC) and low risk cluster (LRC) memberships were derived from cluster analyses of the continuous risk factor scores that predicted sons' EBS scores. Preliminary relative risk ratios show that sons classified into the HRC at age 10-12 were at greater risk for DSM-III-R conduct disorder and SUD outcomes at age 16 than sons assigned to the LRC, SUD + or SUD - groups. Implications for selected family-based prevention initiatives are presented.

A prospective study of the effects of marital status and family relations on young children's adjustment among African American and European American families.

The present study investigated the effects of divorce and family relations on young children's development prospectively, using an ethnically diverse sample of approximately 300 low-income families. We also were able to examine the moderating effects of ethnicity on child adjustment in always two-parent, to-be-divorced, already-divorced, and always single-parent families. Results indicated that to-be-divorced European American and African American families demonstrated higher rates of preschool-age behavior problems, and already-divorced families showed similar trends. Parental conflict and behavior problems accounted for predivorce differences in child behavior problems, whereas rejecting parenting accounted for differences in problem behavior between always single-parent and always two-parent families. The results are discussed in terms of the importance of ethnicity in influencing young, low-income children's adjustment to different family structures.

The detection of nonhybrid, trisomic, and triploid offspring in sexual progeny of a mating of Phytophthora infestans.

Eighty single-oospore offspring of Phytophthora infestans from a mating of isolates, which had previously been analyzed for segregation of avirulence/virulence, were assessed for the inheritance of 20 RFLP markers. Three offspring were triploid; they inherited three alleles at all loci where this could be detected and when heterozygous, showed unequal intensities of hybridization with most probes. Twenty-four offspring were trisomic, as each had three doses of one or a few markers, evident from their inheritance of three alleles or from unequal hybridization to one probe. Coinheritance of the extra allele(s) and mitochondrial haplotype in the majority of trisomic offspring suggested that meiosis in oogonia was more aberrant than in antheridia. Linkage analysis was performed on 50 offspring, which were assumed to be euploid; six small linkage groups were detected and several avirulence loci were found to be linked. The origins of aberrant offspring are discussed.

Assessment of triethylamine and diethylamine emission from military gas mask canisters.

A study was undertaken to evaluate the suitability of four types of amine modified charcoal filter canisters (cartridge) for use with gas masks (respirators) by measuring emissions of triethylamine (TEA) and diethylamine (DEA). Sampling and analysis methods for TEA and DEA were validated and optimized to ensure accurate measurement at low levels. A total of 88 air samples were taken by the validated methods to measure concentrations of TEA and DEA emitted from gas mask canisters during simulated use in an environmental chamber. Samples were collected on a mannequin equipped with a breather pump and also on human volunteers. Very low levels of TEA and moderately low levels of DEA emissions were measured during the simulations. The C7 (KOH-TEA-BPL/ASC3T) gas mask canister giving the lowest emission has been selected for use by the Canadian Forces. The potential health hazard from TEA and DEA for soldiers using the gas masks, under normal conditions, based on estimated use of one to two days per month, for a maximum of 4 hours/day for a normal working lifetime, was considered to be minimal and acceptable.