Where Are The M Dwarf Disks Older Than 10 Million Years?

We present 11.7-micron observations of nine late-type dwarfs obtained at the Keck I 10-meter telescope in December 2002 and April 2003. Our targets were selected for their youth or apparent IRAS 12-micron excess. For all nine sources, excess infrared emission is not detected. We find that stellar wind drag can dominate the circumstellar grain removal and plausibly explain the dearth of M Dwarf systems older than 10 Myr with currently detected infrared excesses. We predict M dwarfs possess fractional infrared excess on the order of L_{IR}/L_{*}\sim10^{-6} and this may be detectable with future efforts.Comment: 24 pages, 2 figures, accepted to Ap

Co-occurrence of aggressive behavior and rule-breaking behavior at age 12: Multi-rater analyses

Aggressive Behavior (AGG) and Rule-Breaking Behavior (RB) are two of the eight CBCL syndromes. The phenotypic correlation between AGG and RB ranges from .48 to .76, and varies depending on the rater and the sex of the child. Prevalence of AGG and RB (i.e., T ≥ 67) is in the range of 6%-7% in both boys and girls. Fifty percent to 60% of the children who are deviant on AGG are also deviant on RB and vice versa. Why so many children show problem behavior in the clinical range for both syndromes is unclear. This co- occurrence could be due to genetic factors influencing both traits, to environmental factors influencing both traits, or to both. The purpose of this study is to use a genetically informative sample to estimate genetic and environmental influences on AGG and RB and to investigate the etiology of the co-occurrence of both behaviors. We do this using multiple informants to take into account underlying sources of parental agreement and disagreement in ratings of their offspring. To this end, mother and father ratings of AGG and RB were collected by using the Child Behavior Checklist in a large sample of 12-year-old twins. Parental agreement is represented by an interparent correlation in the range of .53-.76, depending on phenotype (AGG or RB) and sex of the child. Genetic influences account for 79% and 69% of the individual differences in RB and AGG behavior (defined as AGG and RB on which both parents do agree) in boys. In girls 56% and 72% of the variance in RB and AGG are accounted for by genetic factors. Shared environmental influences are significant for RB in girls only, explaining 23% of the total variance. Eighty percent of the covariance between AGG and RB, similarly assessed by both parents, can be explained by genetic influences. So, co-occurrence in AGG and RB is mainly caused by a common set of genes. Parental disagreement seems to be a combination of so-called rater bias and of parental specific views

Disentangling genetic, environmental and rater effects on internalizing and externalizing problem behavior in 10-year-old twins.

Previous studies have emphasized the importance of rater issues in studying the etiology of variation in internalizing and externalizing problems in children. Earlier results indicate only moderate agreement between parents, and assume that parents assess a specific aspect of their child's behavior. In comparable samples of younger children, additive genetic effects are the main factor explaining individual differences in both internalizing and externalizing behavior. It is unknown whether this pattern of rater influences and variance decomposition will be consistent in older children. Child Behavior Checklists (Achenbach, 1991), completed by both parents, were collected in a sample of 2956 Dutch 10-year-old twin pairs. The etiology of individual differences in internalizing and externalizing syndromes was examined using a model that corrected for possible rater bias, rater-specific effects and unreliability. The best fitting model suggested that disagreement between the parents is not merely the result of unreliability and/or rater bias, but each parent also provides specific information from his/her own perspective on the child's behavior. Significant influences of additive genetic, shared environmental and unique environmental factors were found for internalizing and externalizing syndromes

Automated detection and classification of nuclei in immunohistochemical stainings for Fuchs\u27 endothelial corneal dystrophy

Fuchs’ endothelial corneal dystrophy (FECD) is a degenerative disease that affects the elderly population, and which lacks a unifying pathogenic theory and tangible drug targets. Immunohistochemical stainings can be used to identify proteins involved in the pathogenesis of FECD. We introduce a method for the automatic quantification of the ratio of stained cells starting from full high-resolution cornea images. First, the endothelium is extracted using entropy information in a low-resolution resampling. Then, within the endothelium, we heuristically detect and classify nuclei based on their size, color, and the color of the surrounding cytoplasm. This method achieves comparable results to manual evaluation in a set of corneas of patients with and without FECD

The Patterns of High-Level Magnetic Activity Occurring on the Surface of V1285 Aql: The OPEA Model of Flares and DFT Models of Stellar Spots

Statistically analyzing Johnson UBVR observations of V1285 Aql during the three observing seasons, both activity level and behavior of the star are discussed in respect to obtained results. We also discuss the out-of-flare variation due to rotational modulation. Eighty-three flares were detected in the U-band observations of season 2006 . First, depending on statistical analyses using the independent samples t-test, the flares were divided into two classes as the fast and the slow flares. According to the results of the test, there is a difference of about 73 s between the flare-equivalent durations of slow and fast flares. The difference should be the difference mentioned in the theoretical models. Second, using the one-phase exponential association function, the distribution of the flare-equivalent durations versus the flare total durations was modeled. Analyzing the model, some parameters such as plateau, half-life values, mean average of the flare-equivalent durations, maximum flare rise, and total duration times are derived. The plateau value, which is an indicator of the saturation level of white-light flares, was derived as 2.421{\pm}0.058 s in this model, while half-life is computed as 201 s. Analyses showed that observed maximum value of flare total duration is 4641 s, while observed maximum flare rise time is 1817 s. According to these results, although computed energies of the flares occurring on the surface of V1285 Aql are generally lower than those of other stars, the length of its flaring loop can be higher than those of more active stars.Comment: 44 pages, 10 figures, 5 tables, 2011PASP..123..659

Genetics of testosterone and the aggression-hostility-anger (AHA) syndrome: a study of middle-aged male twins.

Item does not contain fulltex

Neonatal Blood Methylation Marks Associated with Obstetric Pain Relief

The placenta, responsible for intrauterine development, can facilitate modifications within the placental epigenome in response to changes in the mother. In turn these changes have the potential to also influence the neonate1. Pain relief during delivery is widely used and frequently involves the use of nitrous oxide (N2O, commonly referred to as laughing gas), and pudendal blocks. These treatments, alone or in combination, are generally accepted as safe methods of providing pain relief to mothers. However, laughing gas and local anesthetics such as the ones used during pudendal blocks have been known to cross the placental barrier from mother to child2,3. Furthermore, although current literature about the effects of laughing gas and pudendal blocks on the epigenome, when used as maternal pain relief, is very limited, some evidence implicates effects of obstetric anesthesia on the neonatal methylome2,4,5. Thus, it is reasonable to hypothesize that obstetric pain relief administered to the mother during childbirth may affect the methylome of the child. In conclusion, we detected methylome-wide significantly associated loci for laughing gas and pudendal block treatment when studied in combination, but not for either of the treatments separately.https://scholarscompass.vcu.edu/uresposters/1421/thumbnail.jp