Rapid disappearance of a warm, dusty circumstellar disk.

Stars form with gaseous and dusty circumstellar envelopes, which rapidly settle into disks that eventually give rise to planetary systems. Understanding the process by which these disks evolve is paramount in developing an accurate theory of planet formation that can account for the variety of planetary systems discovered so far. The formation of Earth-like planets through collisional accumulation of rocky objects within a disk has mainly been explored in theoretical and computational work in which post-collision ejecta evolution typically is ignored, although recent work has considered the fate of such material. Here we report observations of a young, Sun-like star (TYC 8241 2652 1) where infrared flux from post-collisional ejecta has decreased drastically, by a factor of about 30, over a period of less than two years. The star seems to have gone from hosting substantial quantities of dusty ejecta, in a region analogous to where the rocky planets orbit in the Solar System, to retaining at most a meagre amount of cooler dust. Such a phase of rapid ejecta evolution has not been previously predicted or observed, and no currently available physical model satisfactorily explains the observations.

Cord blood immune biomarkers in small for gestational age births.

Fetal growth restriction is a risk factor for development of adulthood diseases, but the biological mechanism of this association remains unknown. Limited biomarkers have been studied in settings of preterm birth and maternal inflammation, but the relationship between a wide range of immune biomarkers and fetal growth has not been studied. The hypothesis of this study was that fetal growth restriction is associated with altered immune biomarker levels. We examined the relationship between small for gestational age (SGA) status and 27 umbilical cord blood immune biomarkers. This study was part of a large-scale cohort study of preterm birth and low birth weight conducted at Boston Medical Center, an inner city, predominantly minority patient population. Growth status was determined based on birth weight standardized to an internal reference. There were 74 SGA births and 319 appropriate for age (AGA) births with complete clinical and biomarker data. Adjusting for covariates and using AGA as reference, SGA births had lower levels of log IL-1ß (ng/l; ß -0.38, 95% CI -0.57, -0.19, P < 0.01), log BDNF (ß -0.29, 95% CI -0.55, -0.03, P < 0.05) and log NT-3 (ß -0.46, 95% CI -0.77, -0.15, P < 0.01). No associations were found between other biomarkers and SGA. In conclusion, three biomarkers were selectively associated with SGA status. Our results provide information that could be used to guide additional studied aimed at determining mechanisms that contribute to fetal growth.

Images of a fourth planet orbiting HR 8799.

High-contrast near-infrared imaging of the nearby star HR 8799 has shown three giant planets. Such images were possible because of the wide orbits (>25 astronomical units, where 1 au is the Earth-Sun distance) and youth (<100 Myr) of the imaged planets, which are still hot and bright as they radiate away gravitational energy acquired during their formation. An important area of contention in the exoplanet community is whether outer planets (>10 au) more massive than Jupiter form by way of one-step gravitational instabilities or, rather, through a two-step process involving accretion of a core followed by accumulation of a massive outer envelope composed primarily of hydrogen and helium. Here we report the presence of a fourth planet, interior to and of about the same mass as the other three. The system, with this additional planet, represents a challenge for current planet formation models as none of them can explain the in situ formation of all four planets. With its four young giant planets and known cold/warm debris belts, the HR 8799 planetary system is a unique laboratory in which to study the formation and evolution of giant planets at wide (>10 au) separations.

The relationship between maternal depression, in-home violence and use of physical punishment: what is the role of child behaviour?

BACKGROUND: The combined impact of maternal depression and in-home violence, and how their relationship with physical punishment varies with child behaviour are unknown. OBJECTIVES: To determine the combined impact of maternal depression and violence exposure on smacking and explore the role of child behaviours in this relationship. METHODS: Multivariable regression analysis of a sample of kindergarten children. Maternal depressive symptoms, violence exposure and smacking were measured by parent interview. Child behaviours were reported by teachers. RESULTS: 12,764 mother-child dyads were examined. The adjusted odds ratio (aOR) for smacking among depressed mothers was 1.59 (95% CI 1.40 to 1.80), mothers exposed to in-home violence 1.48 (95% CI 1.18 to 1.85) and dually exposed mothers 2.51 (95% CI 1.87 to 3.37). Adjusting for child self-control or externalising behaviour did not change these associations, and no effect modification by child behaviour was detected. Among mothers smacking children, depression was associated with increased smacking frequency (adjusted incident rate ratio (aIRR) 1.12; 95% CI 1.01 to 1.24), but became borderline significant after adjusting for child self-control or externalising behaviour (aIRRs 1.10; 95% CI 1.00 to 1.21). Depressed mothers exposed to violence demonstrated higher rates of smacking (aIRR 1.29; 95% CI 1.09 to 1.53); this remained stable when adjusting for child behaviours. CONCLUSION: Maternal depression and violence exposure are associated with smacking, particularly when depression and violence co-exist, when they are also associated with smacking frequency. Child self-control and externalising behaviour do not substantially impact the association between maternal depressive symptoms, violence exposure and smacking.

Direct imaging of multiple planets orbiting the star HR 8799.

Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step toward imaging Earth-like planets. Imaging detections are challenging because of the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our solar system.

Extreme collisions between planetesimals as the origin of warm dust around a Sun-like star.

The slow but persistent collisions between asteroids in our Solar System generate a tenuous cloud of dust known as the zodiacal light (because of the light the dust reflects). In the young Solar System, such collisions were more common and the dust production rate should have been many times larger. Yet copious dust in the zodiacal region around stars much younger than the Sun has rarely been found. Dust is known to orbit around several hundred main-sequence stars, but this dust is cold and comes from a Kuiper-belt analogous region out beyond the orbit of Neptune. Despite many searches, only a few main-sequence stars reveal warm (> 120 K) dust analogous to zodiacal dust near the Earth. Signs of planet formation (in the form of collisions between bodies) in the regions of stars corresponding to the orbits of the terrestrial planets in our Solar System have therefore been elusive. Here we report an exceptionally large amount of warm, small, silicate dust particles around the solar-type star BD+20,307 (HIP 8920, SAO 75016). The composition and quantity of dust could be explained by recent frequent or huge collisions between asteroids or other 'planetesimals' whose orbits are being perturbed by a nearby planet.

Preschool child care and risk of overweight in 6- to 12-year-old children.

OBJECTIVE: To determine if there is a relationship between center-based child care attendance from ages 3 to 5 y and future overweight at ages 6-12 y. DESIGN/METHODS: Longitudinal, observational study of child experience and future body mass index. SUBJECTS: A total of 1244 US children aged 6-12 y included in the 1997 Panel Study of Income Dynamics Child Development Supplement. MEASUREMENTS: Parent-reported child care attendance from ages 3 to 5 y, trichotomized as 'none', 'limited' (>0 but <15 h/week), and 'extensive' (> or =15 h/week). Overweight defined as a body mass index > or =95th percentile for age and gender. Candidate covariates (selected a priori): gender, race, age, poverty status, birth weight, hours of television per day, Behavior Problems Index score >90th percentile, and Home Observation for Measurement of the Environment-Short Form (HOME-SF) cognitive stimulation score. RESULTS: Of the potential confounding variables, race, HOME-SF cognitive stimulation score, and age significantly altered the relationship between child care attendance and overweight in the multiple logistic regression model. With these covariates in the final model, limited center-based child care attendance from ages 3 to 5 y was independently associated with a decreased risk of overweight at ages 6-12 y (adjusted odds ratio=0.56, 95% confidence interval 0.34, 0.93) relative to no child care attendance. Extensive center-based child care attendance was not associated with future overweight. CONCLUSIONS: Limited center-based child care attendance during the preschool years was independently associated with a decreased risk of future overweight relative to no child care attendance. Additional studies are needed to clarify these findings.

Puerperal adrenal abscess complicating chorioamnionitis.

BACKGROUND: An abscess in the adrenal gland is a rare finding described only a few times in the literature. We present a case report of chorioamnionitis complicated by a puerperal adrenal abscess diagnosed and drained percutaneously using ultrasound and computed tomography. CASE: A 22-year-old woman delivered prematurely because of chorioamnionitis. Amoxicillin clavulanate was administered, and her fever defervesced. Six days later, the patient presented with a temperature of 40C and right flank pain. Workup revealed an abscess in the right adrenal gland, which was diagnosed by computed tomography scan, and then drained percutaneously. Follow-up revealed regression of the abscess to complete recovery. CONCLUSION: Adrenal abscess has not been described in the past as a possible complication of choriamnionitis. It is important to assess the entire abdominal cavity by ultrasound or computed tomography in febrile patients who do not respond to medical therapy.

Molecular epidemiology of preterm delivery: methodology and challenges.

Preterm delivery (PTD) appears to be a complex trait determined by both genetic and environmental factors. Few studies have examined genetic influence on PTD. The overall goal of our study is to examine major candidate genes of PTD and to test gene-environment interactions. Our study includes 500 preterm trios, including 500 preterm babies and their parents and 500 maternal age-matched term controls. We will perform the transmission/disequilibrium test (TDT) on candidate genes thought to be important in each of the four biological pathways of PTD: (1) decidual chorioamionotic inflammation: interleukin 1 (IL-1), IL-6, and tumour necrosis factor (TNF); (2) maternal and fetal stress: corticotropin-releasing hormone (CRH); (3) uteroplacental vascular lesions: methylenetereahydrofolate reductase (MTHFR); and (4) susceptibility to environmental toxins: GSTM1, GSTT1, CYP1A1, CYP2D6, CYP2E1, NAT2, NQO1, ALDH2, and EPHX. We will also perform standard case-control analyses on the 500 preterm cases and 500 term controls to examine gene-environment interactions. The major environmental, nutritional and social factors as well as clinical variables known or suspected to be associated with PTD will be used to test for gene-environment interactions. This study integrates epidemiological and clinical data as well as genetic markers along major pathogenic pathways of PTD. The findings from this study should improve our understanding of genetic influences on PTD and gene-environment interactions.

A mediational model for the impact of exposure to community violence on early child behavior problems.

This study examined how maternal distress mediates the link between exposure to community violence (CV) and the development of early child behavior problems. Research was conducted among 160 children, 3,0 to 5,11 in age, who resided in high-crime neighborhoods. Using structural equation modeling, latent variables were constructed to identify model components: maternal socioeconomic status (SES) and public assistance status, exposure to CV (maternal perceptions of local violence, social disorder, and fear of crime; and frequency of child cowitnessing violent events), family aggression (partner aggression toward mother and partner aggression toward child), maternal distress (global distress and posttraumatic stress disorder symptoms), and early child behavior problems (internalizing and externalizing). Bivariate correlations indicated that CV, maternal distress, and early child behavior problems were significantly intercorrelated. A series of structural equation models was specified to estimate the direct and indirect effect of CV on early child behavior problems. A direct model indicated a significant path from CV to early child behavior problems, after controlling for maternal SES and family aggression. The direct CV-early child behavior problems path diminished, however, when maternal distress was included in the model, after controlling for maternal SES and family aggression. Results are consistent with a mediation model of the impact of maternal distress symptoms on the link between CV and early child behavior problems.

Growth, development, and behavior in early childhood following prenatal cocaine exposure: a systematic review.

CONTEXT: Despite recent studies that failed to show catastrophic effects of prenatal cocaine exposure, popular attitudes and public policies still reflect the belief that cocaine is a uniquely dangerous teratogen. OBJECTIVE: To critically review outcomes in early childhood after prenatal cocaine exposure in 5 domains: physical growth; cognition; language skills; motor skills; and behavior, attention, affect, and neurophysiology. DATA SOURCES: Search of MEDLINE and Psychological Abstracts from 1984 to October 2000. STUDY SELECTION: Studies selected for detailed review (1) were published in a peer-reviewed English-language journal; (2) included a comparison group; (3) recruited samples prospectively in the perinatal period; (4) used masked assessment; and (5) did not include a substantial proportion of subjects exposed in utero to opiates, amphetamines, phencyclidine, or maternal human immunodeficiency virus infection. DATA EXTRACTION: Thirty-six of 74 articles met criteria and were reviewed by 3 authors. Disagreements were resolved by consensus. DATA SYNTHESIS: After controlling for confounders, there was no consistent negative association between prenatal cocaine exposure and physical growth, developmental test scores, or receptive or expressive language. Less optimal motor scores have been found up to age 7 months but not thereafter, and may reflect heavy tobacco exposure. No independent cocaine effects have been shown on standardized parent and teacher reports of child behavior scored by accepted criteria. Experimental paradigms and novel statistical manipulations of standard instruments suggest an association between prenatal cocaine exposure and decreased attentiveness and emotional expressivity, as well as differences on neurophysiologic and attentional/affective findings. CONCLUSIONS: Among children aged 6 years or younger, there is no convincing evidence that prenatal cocaine exposure is associated with developmental toxic effects that are different in severity, scope, or kind from the sequelae of multiple other risk factors. Many findings once thought to be specific effects of in utero cocaine exposure are correlated with other factors, including prenatal exposure to tobacco, marijuana, or alcohol, and the quality of the child's environment. Further replication is required of preliminary neurologic findings.

An evaluation of I Can Cope. Insights into program design and implementation.

The I Can Cope program is an educational program developed to provide information on how to promote physical and emotional well-being to individuals with cancer, their families, and friends. Through focus group and individual interviews and a mailed survey, the effectiveness of the selection, marketing, implementation, and support processes associated with implementing the program in the central Arizona and greater Las Vegas, Nevada, regions was evaluated. Findings, recommendations, lessons learned, and use of findings are discussed.

Primary care pediatricians' roles and perceived responsibilities in the identification and management of depression in children and adolescents.

OBJECTIVE: To describe primary care pediatricians' 1) approach to the identification and management of childhood and adolescent depression and 2) perception of their skills, responsibilities, and barriers in recognizing and managing depression in children and adolescents. DESIGN AND METHODS: National cross-sectional survey of randomly selected primary care pediatricians that assessed the management of recalled last case of child or adolescent depression, attitudes, limitations to care from barriers and skills, and willingness to implement new educational or intervention strategies to improve care. RESULTS: There were 280 completed surveys about child and adolescent depression (63% response rate). Pediatricians overwhelmingly reported it was their responsibility to recognize depression in both children and adolescents (90%) but were unlikely to feel responsible for treating children or adolescents (26%-27%). Those with most of their practice in capitated managed care were less likely to feel responsible for recognizing depression in either children or adolescents. Forty-six percent of pediatricians lacked confidence in their skills to recognize depression in children, and few of them (10%-14%) had confidence in their skills in different aspects of treatment with children or adolescents. Diagnostic, assessment, and management details for their last recalled case of depression in a child or adolescent were provided by 248 of these pediatricians. In addition to referring 78%-79% of the cases to mental health care professionals, 77% of pediatricians provided a wide range of brief interventions. Only 19%-20% prescribed medication. Major factors cited that limited their diagnosis or management were time (56%-68%) and training or knowledge of issues (38%-56%). Fewer pediatricians noted limitations due to insurer or financial issues (8%-39%) or patient issues (19%-31%). The 35% of pediatricians who were motivated to change their recognition and management of suspected depression were significantly more interested in implementing in the future a variety of new strategies to improve care. CONCLUSION: Primary care pediatricians felt responsible for recognizing but not for treating child and adolescent depression. Although the lack of confidence and lack of knowledge and/or skills and time issues are major barriers that limit pediatricians in their treatment of childhood and adolescent depression, pediatricians varied in their readiness to change, with some being more willing to implement new strategies to care for depression. Educational and practice interventions need to focus on how to assist all pediatricians in diagnosis and to prepare these motivated pediatricians to manage depression in primary care settings.

A public health response to emerging technology: expansion of the Massachusetts newborn screening program.

The development of a new technology, called tandem mass spectrometry (tandem MS), has challenged governments worldwide to consider expanding universal newborn screening for rare metabolic disorders. In 1997 the Massachusetts Department of Public Health developed a public process to meet this challenge. After addressing significant medical, legal, ethical, and logistical issues raised by tandem MS, Massachusetts incorporated one new disorder into the mandatory newborn screen and developed an optional pilot program for 20 additional disorders. The Massachusetts experience has wide relevance for other nations and states. As screening protocols are contemplated for entire populations-for newborns and others- it will remain essential that the public participate in an open process of reviewing the justification for and logistics of screening.