Local Visual Processing in High Obsessive Compulsive Disorder (OCD) Scorers.

<p>Reaction times for big and small letters (global and local levels) were compared and examined to see whether differences would occur between a low scoring and high scoring Obsessive- Compulsive Disorder (OCD) group. OCD patients have been shown to notice and pay more attention to small details (local bias) compared to most other populations (Shapiro, 1965; Yovel et al. 2006; Caberea et al., 2001). Although there is research supporting a local bias in OCD patients, it is unclear whether the bias occurs in the early stages of visual processing or in a later memory stage (Moritz & Wendt, 2006; Hermans et al, 2008). The study specifically examined a potential local bias for high OCD scorers in the early visual stage by manipulating perceptual and attentional mechanisms in two hierarchical letter tasks (Navon, 1977; Miller, 1981a, Plaisted et al. 1999). In Experiment 1, participants were told which level (the big or small letter) to respond to, results showed that high OCD scorers responded faster to local letters, showing support for a local processing advantage. Conversely, the low OCD group responded quicker to the global level. The finding of a local advantage in Experiment 1 suggests that the local advantage may be due to perceptual mechanisms as attention was already directed to the relevant level. However, in Experiment 2 where attention was not directed and the image quality was manipulated, local and global advantage effects were not replicated for the high and low OCD groups respectively. This showed that attentional and perceptual mechanisms did not make one level easier to process over the other. Therefore, it is possible that any local bias for OCD patients occurs in a later processing stage.</p>

Local Visual Processing in High Obsessive Compulsive Disorder (OCD) Scorers.

<p>Reaction times for big and small letters (global and local levels) were compared and examined to see whether differences would occur between a low scoring and high scoring Obsessive- Compulsive Disorder (OCD) group. OCD patients have been shown to notice and pay more attention to small details (local bias) compared to most other populations (Shapiro, 1965; Yovel et al. 2006; Caberea et al., 2001). Although there is research supporting a local bias in OCD patients, it is unclear whether the bias occurs in the early stages of visual processing or in a later memory stage (Moritz & Wendt, 2006; Hermans et al, 2008). The study specifically examined a potential local bias for high OCD scorers in the early visual stage by manipulating perceptual and attentional mechanisms in two hierarchical letter tasks (Navon, 1977; Miller, 1981a, Plaisted et al. 1999). In Experiment 1, participants were told which level (the big or small letter) to respond to, results showed that high OCD scorers responded faster to local letters, showing support for a local processing advantage. Conversely, the low OCD group responded quicker to the global level. The finding of a local advantage in Experiment 1 suggests that the local advantage may be due to perceptual mechanisms as attention was already directed to the relevant level. However, in Experiment 2 where attention was not directed and the image quality was manipulated, local and global advantage effects were not replicated for the high and low OCD groups respectively. This showed that attentional and perceptual mechanisms did not make one level easier to process over the other. Therefore, it is possible that any local bias for OCD patients occurs in a later processing stage.</p>

Development Of A Calibration Source For Measurement Of Gaseous Oxidized Mercury In Ambient Air

A HgCl₂ containing diffusion source was evaluated for its potential usefulness as a calibration source for gaseous oxidized mercury (GOM) measurements. Unlike previous calibration sources described in the literature, this source made use of a flow rate of at least 1 L min-¹, and was maintained at a temperature of as low as - 15oC. Under these conditions, the source was found to emit GOM at an environmentally relevant level of 0.0905 pg s-¹, with a GOM fraction of approximately 78%. The source was found to have a consistent response to temperature, a steady state emission level of Hg could be rapidly established and the source was temporally stable. Duplicate sources were compared with one another and found to emit similar levels of Hg under identical sampling conditions. Various methods of cleaning HgCl₂ contaminated items were tested, with the most successful method using a stannous chloride wash solution.

Development Of A Calibration Source For Measurement Of Gaseous Oxidized Mercury In Ambient Air

A HgCl₂ containing diffusion source was evaluated for its potential usefulness as a calibration source for gaseous oxidized mercury (GOM) measurements. Unlike previous calibration sources described in the literature, this source made use of a flow rate of at least 1 L min-¹, and was maintained at a temperature of as low as - 15oC. Under these conditions, the source was found to emit GOM at an environmentally relevant level of 0.0905 pg s-¹, with a GOM fraction of approximately 78%. The source was found to have a consistent response to temperature, a steady state emission level of Hg could be rapidly established and the source was temporally stable. Duplicate sources were compared with one another and found to emit similar levels of Hg under identical sampling conditions. Various methods of cleaning HgCl₂ contaminated items were tested, with the most successful method using a stannous chloride wash solution.

Interactions between strains govern the eco-evolutionary dynamics of microbial communities

Genomic data has revealed that genotypic variants of the same species, i.e., strains, coexist and are abundant in natural microbial communities. However, it is not clear if strains are ecologically equivalent, or if they exhibit distinct interactions and dynamics. Here, we address this problem by tracking 10 microbial communities from the pitcher plant Sarracenia purpurea in the laboratory for more than 300 generations. Using metagenomic sequencing, we reconstruct their dynamics over time and across scales, from distant phyla to closely related genotypes. We find that interactions between naturally occurring strains govern eco-evolutionary dynamics. Surprisingly, even fine-scale variants differing only by 100 base pairs can exhibit vastly different dynamics. We show that these differences may stem from ecological interactions in the communities, which are specific to strains, not species. Finally, by analyzing genomic differences between strains, we identify major functional hubs such as transporters, regulators, and carbohydrate-catabolizing enzymes, which might be the basis for strain-specific interactions. Our work shows that strains are the relevant level of diversity at which to study the long-term dynamics of microbiomes.