Blood lead (Pb) levels: Further evidence for an environmental mechanism explaining the association between socioeconomic status and psychophysiological dysregulation in children.

Objective: The authors recently reported that blood lead (Pb) was a significant mediator for the positive association between socioeconomic status (SES) and peripheral vascular responses to acute stress in children (B. B. Gump et al., 2007). The present study considers the possibility that Pb may also mediate an association between SES and cortisol responses to acute stress. Design: Early childhood Pb exposure was tested as a mediator for cross-sectional associations between SES and cortisol responses. Main Outcome Measures: The primary outcome was cortisol responses to acute stress in 9.5-year-old children (N = 108). Results: Lower family income was associated with significantly greater cortisol levels following an acute stress task. A mediational analysis confirmed that Pb was a significant mediator for this association. Conclusion: These results reaffirm the importance of considering the chemical environment as well as social and psychological environment when evaluating psychophysiological effects of low SES. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Challenges to Bayesian decision support using morphological matrices for design: empirical evidence

A novel Bayesian design support tool is empirically investigated for its potential to support the early design stages. The design support tool provides dynamic guidance with the use of morphological design matrices during the conceptual or preliminary design stages. This paper tests the appropriateness of adopting a stochastic approach for supporting the early design phase. The rationale for the stochastic approach is based on the uncertain nature of the design during this part of the design process. The support tool is based on Bayesian belief networks (BBNs) and uses a simple but effective information content–based metric to learn or induce the model structure. The dynamically interactive tool is assessed with two empirical trials. First, the laboratory-based trial with novice designers illustrates a novel emergent design search methodology. Second, the industrial-based trial with expert designers illustrates the hurdles that are faced when deploying a design support tool in a highly pressurised industrial environment. The conclusion from these trials is that there is a need for designers to better understand the stochastic methodology for them to both be able to interpret and trust the BBN model of the design domain. Further, there is a need for a lightweight domain-specific front end interface is needed to enable a better fit between the generic support tool and the domain-specific design process and associated tools.     

Divergent thinking ability is related to faster relatedness judgments.

Creativity is commonly defined as the novel and useful combination of concepts previously thought to be unrelated. Fundamentally, this process rests on the ability to judge relatedness between concepts. The authors conducted an experiment to test the connection between divergent thinking ability and the speed of judging relatedness. Our results demonstrated that people with higher divergent thinking ability are faster in judging whether two concepts are related or unrelated. In real life, this can lead to a substantial advantage in the number of potentially useful relationships that could be assessed per unit of time. Equally important, there was no link between IQ and speed of judging relatedness. These results are interpreted in relation to a recently proposed model of creative cognition suggesting that creative people are faster in information processing under conditions of low ambiguity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integration of superconducting magnets with cryogen-free dilution refrigerator systems

There has been much recent research interest into “cryogen-free” dilution refrigerators. Cryogen-free systems have some advantages from a safety and convenience point of view as liquid cryogens are unnecessary. However, this also makes integrating the low-temperature system with a high magnetic field environment much more challenging. Here we shall describe recent successes of integrating superconducting magnets and dilution refrigerators into one system requiring a single pulse tube cooler. The resulting environment provides experimental temperatures between 7 mK and 30 K and magnetic fields up to 12 T. We shall describe the effects of AC loss heating in such systems on the pulse tube refrigerator when the field is ramped and also the effects of eddy current heating on the mixing chamber in sweeping fields.     

Effect of the initial dose of foot-and-mouth disease virus on the early viral dynamics within pigs

This paper investigates the early viral dynamics of foot-and-mouth disease (FMD) within infected pigs. Using an existing within-host model, we investigate whether individual variation can be explained by the effect of the initial dose of FMD virus. To do this, we consider the experimental data on the concentration of FMD virus genomes in the blood (viral load). In this experiment, 12 pigs were inoculated with one of three different doses of FMD virus: low; medium; or high. Measurements of the viral load were recorded over a time course of approximately 11 days for every 8 hours. The model is a set of deterministic differential equations with the following variables: viral load; virus in the interstitial space; and the proportion of epithelial cells available for infection, infected and uninfected. The model was fitted to the data for each animal individually and also simultaneously over all animals varying only the initial dose. We show that the general trend in the data can be explained by varying only the initial dose. The higher the initial dose the earlier the development of a detectable viral load.     

Design issues in a mandatory greenhouse gas emissions registry for the United States

On March 10, 2009, the US Environmental Protection Agency (EPA) proposed a new rule, Mandatory Reporting of Greenhouse Gases. When final, the rule would compel most large sources of greenhouse gases (GHGs) to report their emissions to EPA as well as fossil fuel suppliers and vehicle engine manufacturers to report their fuel sales and engine emissions rates, respectively. We suggest a number of improvements to the rule that would enhance compatibility with expected future climate legislation and enable a broader range of policies and analysis: (1) lower the threshold for reporting to a level more consistent with expected future legislation, (2) require reporting of electricity use along with direct emissions, (3) require reporting of emissions per unit output for a small number of selected sectors, (4) include a system of identifying corporate ownership of reporting facilities, and (5) identify a path toward coverage for sectors that were left out of the proposal due to underdeveloped reporting protocols.     

Effect of irrigation method on transmission to and persistence of Escherichia coli O157:H7 on lettuce

In this study, the transmission of Escherichia coli O157:H7 to lettuce plants through spray and surface irrigation was demonstrated. For all treatments combined, the number of plants testing positive following a single exposure to E. coli O157: H7 through spray irrigation (29 of 32 plants) was larger than the number testing positive following surface irrigation (6 of 32 plants). E. coli O157:H7 persisted on 9 of 11 plants for 20 days following spray irrigation with contaminated water. Immersion of harvested lettuce heads for 1 min in a 200 ppm chlorine solution did not eliminate all E. coli O157:H7 cells. The results of this study suggest that regardless of the irrigation method used, crops can become contaminated; therefore, the irrigation of food crops with water of unknown microbial quality should be avoided.     

Hairline lowering during foreheadplasty

Many patients seeking rejuvenation of their foreheads have high hairlines and are troubled by the prospect that surgery will worsen the deformity. Hairline elevation occurs in both coronal and endoscopic foreheadplasty techniques and is at least part of the reason that many surgeons do not always recommend these procedures when otherwise indicated. Although a pretrichial "hairline" incision prevents hairline retro-displacement, it results in forehead shortening only and not true hairline lowering. When a pretrichial incision is used in combination with a posterior scalp advancement flap, however, true hairline lowering is possible. Experience with this technique encompasses 27 procedures performed over a 5-year period. Patients ranged in age from 35 to 71 years. A significant improvement was demonstrable in all cases and corresponded with a high degree of patient satisfaction. No serious complications were seen. A high hairline must be recognized as the source of both a disproportionate and aged appearance. The ability to lower the hairline and place it in a more proportionate, youthful relationship with the rest of the face adds a new dimension to foreheadplasty equal to or greater in importance to an overall improved appearance as other maneuvers typically performed during the procedure. For many patients, the benefits of hairline lowering far outweigh the trade-off of a more anteriorly situated, and possibly more visible, scar.     

Protein kinase C regulates a vesicular class of calcium channels in the bag cell neurons of aplysia

Protein kinase C (PKC) acutely increases calcium currents in Aplysia bag cell neurons by recruiting calcium channels different from those constitutively active in the plasma membrane. To study the mechanism of PKC regulation we previously identified two calcium channel alpha1-subunits expressed in bag cell neurons. One of these, BC-alpha1A, is localized to vesicles concentrated primarily in somata and growth cones. We used antibodies to BC-alpha1A to analyze its expression in the bag cell neurons of juvenile Aplysia at a developmental stage at which PKC-sensitive calcium currents have previously been shown to be low. We find that vesicular BC-alpha1A staining is generally reduced in juvenile bag cell neurons but that its expression level can vary among juvenile animals. In 17 bag cell clusters examined, the percentage of neurons that displayed punctate alphaBC-alpha1A staining ranged from 0 to 85%. Sampling of calcium currents from cells of the same clusters by whole cell patch-clamp techniques revealed that the PKC-sensitive calcium current density is significantly correlated with the degree of vesicular staining. In contrast, no correlation of basal calcium current levels with aBC-alpha1A staining was found. These results strongly suggest that BC-alpha1A, a member of the ABE-subfamily of calcium channels, carries the PKC-sensitive calcium current in bag cell neurons. They are consistent with a model in which PKC recruits channels from the vesicular pool to the plasma membrane.