Why so impulsive? White matter alterations are associated with impulsivity in chronic marijuana smokers.

Difficulty monitoring and inhibiting impulsive behaviors has been reported in marijuana (MJ) smokers; neuroimaging studies, which examined frontal systems in chronic MJ smokers, have reported alterations during inhibitory tasks. Diffusion tensor imaging (DTI) provides a quantitative estimate of white matter integrity at the microstructural level. We applied DTI, clinical ratings, and impulsivity measures to explore the hypotheses that chronic, heavy MJ smokers would demonstrate alterations in white matter microstructure and a different association between white matter measures and impulsivity relative to nonsmoking control subjects (NS). Fractional anisotropy (FA), a measure of directional coherence, and trace, a measure of overall diffusivity, were calculated for 6 locations including bilateral frontal regions in 15 chronic MJ smokers and 15 NS. Subjects completed clinical rating scales, including the Barratt Impulsivity Scale (BIS). Analyses revealed significant reductions in left frontal FA in MJ smokers relative to NS and significantly higher levels of trace in the right genu. MJ smokers also had significantly higher BIS total and motor subscale scores relative to NS, which were positively correlated with left frontal FA values. Finally, age of onset of MJ use was positively correlated with frontal FA values and inversely related to trace. These data represent the first report of significant alterations in frontal white matter tracts associated with measures of impulsivity in chronic MJ smokers. Early MJ use may result in reduced FA and increased diffusivity, which may be associated with increased impulsivity, and ultimately contribute to the initiation of MJ use or the inability to discontinue use. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Methadone maintenance improves cognitive performance after two months of treatment.

Methadone maintenance (MM) has received little scientific attention regarding neurocognitive effects. The present study examined cognitive function in 17 opiate-dependent subjects at baseline and after 2 months of MM treatment. Subjects demonstrated significant improvements from baseline on measures of verbal learning and memory, visuospatial memory, and psychomotor speed and reduced frequency of drug use (Addiction Severity Index) relative to baseline, although the total percentage of urine samples positive for additional illicit substances was slightly increased. No effect of illicit drug use was observed when the sample was stratified by urine toxicology results, suggesting that improvements in cognition were not associated with additional illicit drug use. Results suggest that opiate-dependent subjects exhibit significant improvement in cognitive function after MM treatment. Future investigations are needed to confirm these findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Atmospheric transport and outflow of polycyclic aromatic hydrocarbons from China

A potential receptor influence function (PRIF) model, based on air mass forward trajectory calculations, was applied to simulate the atmospheric transport and outflow of polycyclic aromatic hydrocarbons (PAHs) emitted from China. With a 10 day atmospheric transport time, most neighboring countries and regions, as well as remote regions, were influenced by PAH emissions from China. Of the total annual PAH emission of 114 Gg, 92.7% remained within the boundary of mainland China. The geographic distribution of PRIFs within China was similar to the geographic distribution of the source regions, with high values in the North China Plain, Sichuan Basin, Shanxi, and Guizhou province. The Tarim basin and Sichuan basin had unfavorable meteorological conditions for PAH outflow. Of the PAH outflow from China (8092 tons or 7.1% of the total annual PAH emission), approximately 69.9% (5655 tons) reached no further than the offshore environment of mainland China and the South China Sea. Approximate 227, 71, 746, and 131 tons PAHs reached North Korea, South Korea, Russia-Mongolia region, and Japan, respectively, 2-4 days after the emission. Only 1.4 tons PAHs reached North America after more than 9 days. Interannual variation in the eastward PAH outflow was positively correlated to cold episodes of El Ni?o/Southern Oscillation. However, trans-Pacific atmospheric transport of PAHs from China was correlated to Pacific North America index (PNA) which is associated with the strength and position of westerly winds.     

Influence of Asian and Western United states agricultural areas and fires on the atmospheric transport of pesticides in the Western United States

Historic and current use pesticides (HUPs and CUPs), with respect to use in the United States and Canada, were identified in trans-Pacific and regional air masses at Mt. Bachelor Observatory (MBO), a remote high elevation mountain in Oregon's Cascade Range located in the United States, during the sampling period of April 2004 to May 2006 (n = 69), including NASA's INTEX-B campaign (spring 2006). Elevated hexachlorobenzene (HCB) and alpha-hexachlorocyclohexane (alpha-HCH) concentrations were measured during trans-Pacific atmospheric transport events at MBO, suggesting that Asia is an important source region for these HUPs. Regional atmospheric transport events at MBO resulted in elevated dacthal, endosulfan, metribuzin, triallate, trifluralin, and chlorpyrifos concentrations, with episodic increases in concentration during some spring application periods, suggesting that the Western U.S. is a significant source region for these CUPs. Endosulfan I, gamma-HCH, and dacthal concentrations were significantly positively correlated (p-value < 0.05) with increased air mass time in Western U.S. agricultural areas. Elevated gamma-HCH concentrations were measured at MBO during both trans-Pacific and regional atmospheric transport events, including regional fire events. In addition to gamma-HCH, elevated sigmachlordane, alpha-HCH, HCB, and trifluralin concentrations were associated with fires in Western North America due to revolatilization of these pesticides from soils and vegetation. Trans-chlordane/cis-chlordane and alpha-HCH/gamma-HCH ratios were calculated and may be used to distinguish between free tropospheric and regional and/or Asian air masses.     

Influence of Asian and Western United States urban areas and fires on the atmospheric transport of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fluorotelomer alcohols in the Western United States

Atmospheric measurements of semivolatile organic compounds (SOCs) were made at Mt Bachelor Observatory (MBO), located in Oregon's Cascade Range, to understand the trans-Pacific and regional transport of SOCs from urban areas. High volume air sampling (approximately 644 m3 for 24 h periods) of both the gas and particulate phases was conducted from April 19, 2004 to May 13, 2006 (n = 69); including NASA's INTEX-B campaign in spring 2006 (n = 34 of 69). Air mass back trajectories were calculated and were used to calculate source region impact factors (SRIFs), the percentage of time the sampled air mass resided in a given source region. Particulate-phase polycyclic aromatic hydrocarbon (PAH) concentrations at MBO increased with the percentage of air mass time in Asia and, in conjunction with other data, provided strong evidence that particulate-phase PAHs are emitted from Asia and undergo trans-Pacific atmospheric transport to North America. Gas-phase PAH and fluorotelomer alcohol (FTOH) concentrations significantly increased with the percentage of air mass time in California's urban areas, whereas retene and polychlorinated biphenyl (PCB) concentrations increased with the percentage of air mass time in Oregon and during regional fire events. In addition, sigma(gas-phase) PAH, retene, and levoglucosan concentrations were significantly correlated (p-value < 0.001) with sigma(PCB) concentrations, suggesting that increased atmospheric PCB concentrations were associated with fires due to the volatilization of stored PCBs from soil and vegetation.     

Adult conflict history and children's subsequent responses to conflict: An experimental test.

Although correlations between marital conflict histories and increased reactivity by children during conflict exposure are well documented (i.e., sensitization), questions about causality remain unresolved. This study subjected the sensitization hypothesis, which is a critical prediction of several theories about interparental conflict, to an experimental test. Children in 3 age groups (early childhood, preadolescence, late adolescence) viewed videotapes of an adult couple engaged in a history of (a) 4 hostile, unresolved conflicts (destructive) or (b) 4 mild, resolved conflicts (constructive). Next, all children were interviewed about their responses after witnessing a standard conflict between the same adult couple. Supporting the sensitization hypothesis, destructive conflict histories elicited more negative patterns of responding across multiple domains; age and gender moderated many effects. Results suggested that constructive conflict histories had benign effects on children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reductions in emissions of carbonaceous particulate matter and polycyclic aromatic hydrocarbons from combustion of biomass pellets in comparison with raw fuel burning

Biomass pellets are emerging as a cleaner alternative to traditional biomass fuels. The potential benefits of using biomass pellets include improving energy utilization efficiency and reducing emissions of air pollutants. To assess the environmental, climate, and health significance of replacing traditional fuels with biomass pellets, it is critical to measure the emission factors (EFs) of various pollutants from pellet burning. However, only a few field measurements have been conducted on the emissions of carbon monoxide (CO), particulate matter (PM), and polycyclic aromatic hydrocarbons (PAHs) from the combustion of pellets. In this study, pine wood and corn straw pellets were burned in a pellet burner (2.6 kW), and the EFs of CO, organic carbon, elemental carbon, PM, and PAHs (EF(CO), EF(OC), EF(EC), EF(PM), and EF(PAH)) were determined. The average EF(CO), EF(OC), EF(EC), and EF(PM) were 1520 ± 1170, 8.68 ± 11.4, 11.2 ± 8.7, and 188 ± 87 mg/MJ for corn straw pellets and 266 ± 137, 5.74 ± 7.17, 2.02 ± 1.57, and 71.0 ± 54.0 mg/MJ for pine wood pellets, respectively. Total carbonaceous carbon constituted 8 to 14% of the PM mass emitted. The measured values of EF(PAH) for the two pellets were 1.02 ± 0.64 and 0.506 ± 0.360 mg/MJ, respectively. The secondary side air supply in the pellet burner did not change the EFs of most pollutants significantly (p > 0.05). The only exceptions were EF(OC) and EF(PM) for pine wood pellets because of reduced combustion temperatures with the increased air supply. In comparison with EFs for the raw pine wood and corn straw, EF(CO), EF(OC), EF(EC), and EF(PM) for pellets were significantly lower than those for raw fuels (p < 0.05). However, the differences in EF(PAH) were not significant (p > 0.05). Based on the measured EFs and thermal efficiencies, it was estimated that 95, 98, 98, 88, and 71% reductions in the total emissions of CO, OC, EC, PM, and PAHs could be achieved by replacing the raw biomass fuels combusted in traditional cooking stoves with pellets burned in modern pellet burners.     

Coaching versus therapy: A perspective.

This article reports a study of current perceptions among professionals regarding therapy and coaching. Whereas therapy and counseling have been traditional fields of study and practice, coaching is not as well developed. It is helpful to examine the perceptions of practicing professionals in order to delineate the distinctions and overlaps in these modalities. A set of 7 questions was used to explore these viewpoints with a participant pool of professional coaches--therapists. Interview data and narrative summaries provide a perspective on the controversy of coaching versus therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Relation of Children's Everyday Nonsocial Peer Play Behavior to Their Emotionality, Regulation, and Social Functioning.

The relations of children's nonsocial behavior to their emotionality, regulation, and social functioning were examined in a short-term longitudinal study. Parents (primarily mothers) and teachers rated children's effortful regulation, emotionality, asocial behaviors, problem behaviors, and social acceptance, and children's nonsocial play behaviors were observed for two semesters. Peers also rated likability. Children's observed reticent activities were related to adults' ratings of high regulation, low externalizing problems, and high asocial behavior, as well as to low anger and low positive emotion. On the other hand, solitary play was associated with low positive emotion and low regulation over time and with high asocial behavior and high peer exclusion. Peer rejection mediated the relation of internalizing emotions (anxiety, low positive emotion) and regulation to solitary play later in the school year, and asocial play mediated the relation of internalizing emotions to both solitary and reticent play behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spray irrigation of treated municipal wastewater as a potential source of atmospheric PBDEs

Spray irrigation facilities utilizing treated municipal wastewater are a potential source of polybrominated diphenyl ethers (PBDEs) to the atmosphere. PBDEs are used as flame retardants in many household items and have been found in wastewaters and biosolids. Evidence of PBDE release from spray irrigation facilities was discovered during a multiyear project to measure semivolatile organic chemical concentrations in air. Four BDE congeners (47, 99, 100, and 154) were monitored at three remote/ rural locations in Maryland and Delaware from 2001 to 2003. Average concentrations at two of the sites (BDE-47, 10-17 pg/m3; BDE-99, 5.3-7.7 pg/m3) reflect background levels. Average concentrations at the third location were 5-10 times higher (BDE-47, 175 pg/m3; BDE-99, 26 pg/m3) and were significantly correlated (p < 0.0001) with temperature indicating local source(s). Several spray irrigation facilities are located south and west of the third site, the prevailing wind direction during the spring and summer when most samples were collected. The fine mist released from the irrigation equipment may enhance release to the atmosphere via air-water gas exchange from water droplets. Temporal trends indicate that aerial concentrations of PBDEs in this area are increasing at an exponential rate; the atmospheric doubling times for the different congeners range from 1.1 to 1.7 yrs.