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Four sets of nonreactive solute transport experiments were conducted with micromodels. Each set consisted of three experiments with one variable, i.e., flow velocity, grain diameter, pore-aspect ratio, and flow-focusing heterogeneity. The data sets were offered to pore-scale modeling groups to test their numerical simulators. Each set consisted of two learning experiments, for which all results were made available, and one challenge experiment, for which only the experimental description and base input parameters were provided. The experimental results showed a nonlinear dependence of the transverse dispersion coefficient on the Peclet number, a negligible effect of the pore-aspect ratio on transverse mixing, and considerably enhanced mixing due to flow focusing. Five pore-scale models and one continuum-scale model were used to simulate the experiments. Of the pore-scale models, two used a pore-network (PN) method, two others are based on a lattice Boltzmann (LB) approach, and one used a computational fluid dynamics (CFD) technique. The learning experiments were used by the PN models to modify the standard perfect mixing approach in pore bodies into approaches to simulate the observed incomplete mixing. The LB and CFD models used the learning experiments to appropriately discretize the spatial grid representations. For the continuum modeling, the required dispersivity input values were estimated based on published nonlinear relations between transverse dispersion coefficients and Peclet number. Comparisons between experimental and numerical results for the four challenge experiments show that all pore-scale models were all able to satisfactorily simulate the experiments. The continuum model underestimated the required dispersivity values, resulting in reduced dispersion. The PN models were able to complete the simulations in a few minutes, whereas the direct models, which account for the micromodel geometry and underlying flow and transport physics, needed up to several days on supercomputers to resolve the more complex problems.

Evolution of life history traits can occur rapidly and has the potential to influence ecological processes, which can also be shaped by abiotic and biotic factors. Few studies have shown that life history phenotype can affect ecological processes as much as commonly studied biotic ecological variables, but currently we do not know how the ecological effects of life history phenotype compare in size to the effects of abiotic factors, or whether the ecological effects of phenotypes are sensitive to variability in abiotic conditions. Using a factorial mesocosm experiment we compared the ecosystem effects of guppy Poecilia reticulata life history phenotypes in two light treatments representing a four‐fold difference in light levels, which was comparable to upstream downstream differences in light availability in Trinidadian streams. Light and phenotype had significant effects on similar aspects of ecosystem function. Whereas light had a stronger effect on ecosystem structure (algal and invertebrate stocks) than phenotype, phenotype and light had nearly equal effects on many ecosystem processes (nutrient recycling, nutrient fluxes, ecosystem metabolism and leaf litter decomposition). Light had a stronger effect on most guppy life history traits and guppy fitness than differences between phenotypes. The effect of light on these traits was consistent with higher availability of food resources in the high light treatments. Interactions between light and phenotype were weak for the majority of response variables suggesting that abiotic variability did not alter the mechanisms by which phenotypes affect ecosystem function. We conclude that subtle phenotypic differences in consumers can affect ecosystem processes as much as meaningful variability in abiotic factors which until recently were thought to be the primary drivers of ecosystem function in nature. However, despite its effects on traits and the ecosystem, light did not alter the effect of guppy phenotype on ecosystem function.

The transcription factor GATA-1 and its cofactor, friend of GATA-1 (FOG-1), are essential for normal erythroid development. FOG-1 physically interacts with GATA-1 to augment or inhibit its activity. The mechanisms by which FOG-1 regulates GATA-1 function are unknown. By using an assay that is based on the phenotypic rescue of a GATA-1-null erythroid cell line, we found that a conditional form of GATA-1 (GATA-1-ER) strongly induced histone acetylation at the β-major globin promoter in vivo, consistent with previous results. In contrast, GATA-1 bearing a point mutation that impairs FOG-1 binding [GATA-1(V205M)-ER] failed to induce high levels of histone acetylation at this site. However, at DNase I-hypersensitive site (HS)3 of the β-globin locus control region, GATA-1-induced histone acetylation was FOG-1-independent. Because the V205M mutation does not disrupt GATA-1 binding to DNA templates in vitro, we were surprised to find that in vivo GATA-1(V205M)-ER fails to bind the β-globin promoter. However, at HS3, DNA binding by GATA-1 was FOG-1-independent, thus correlating histone acetylation with GATA-1 occupancy. Examination of additional GATA-1-dependent regulatory elements showed that the interaction with FOG-1 is required for GATA-1 occupancy at select sites, such as HS2, but is dispensable at others, including the FOG-1-independent GATA-1 target gene EKLF. Remarkably, at the GATA-2 gene, which is repressed by GATA-1, interaction with FOG-1 was dispensable for GATA-1 occupancy and was required for transcriptional inhibition and histone deacetylation. These results indicate that FOG-1 employs distinct mechanisms when cooperating with GATA-1 during transcriptional activation and repression.

Hypertrophic cardiomyopathy, a disorder occurring in approximately 1 of every 500 people, causes a broad spectrum of pathological findings and clinical manifestations. 1 , 2 Early observations 2 , 3 emphasized the morphologic features of this disease (e.g., marked septal hypertrophy and subaortic obstruction) and its unfavorable natural history (e.g., progressive symptoms, serious arrhythmias, heart failure, and sudden death). Today the anatomical and clinical expression of the disease is recognized to encompass a wider range of phenotypes, including mild or focal hypertrophy, limited symptoms, and a good prognosis. Molecular genetic studies of familial hypertrophic cardiomyopathy have demonstrated that this autosomal dominant condition is caused . . .

The behavioral theory constructs most often used to study mammography utilization—perceived benefit, perceived susceptibility, self-efficacy, intention, and subjective norms—have neither been developed nor sufficiently tested among diverse racial/ethnic subgroups. The authors explored these constructs and their underlying assumptions relating to the social context of Filipina and Latina women. The mixed-methods study included testing construct measures in the multilingual surveys of a concurrent intervention study of 1,463 women from five ethnic groups. An intensive inductive investigation then targeted Latina and Filipina women to elucidate connections between social context and individual screening behavior. In-depth interviews were conducted with 11 key informant scholars, 13 community gatekeepers, and 29 lay women, and a supplemental study videotaped and interviewed 9 mother-daughter dyads. Three social context domains emerged: relational culture, social capital, and transculturation and transmigration. The meaning and appropriateness of the five behavioral constructs were analyzed in relation to these domains. In contradistinction to tenets of behavioral theory, the authors found that social context can influence behavior directly, circumventing or attenuating the influence of individual beliefs; contextual influences, synthesized from multiple perspectives, can operate at an unconscious level not accessible to the individual; and contextual influences are dynamic, contingent on distal and proximal forces coming together in a given moment and are thus not consistent with an exclusive focus at the individual level. This article describes the study methods, summarizes main findings, and previews the detailed results presented in the other articles in this issue.

Women treated with chest radiation for a pediatric cancer have low mammography screening rates despite their high risk for breast cancer. This study characterized the relationship between perceptions of mammography and screening practices. A cross-sectional survey was administered to 523 women in North America who were treated with chest radiation before 21 years of age. Women with inconsistent mammography perceptions and practices were identified using the Pros and Cons of Mammography for perceptions and Transtheoretical Model stages of adoption for prior and intended screening practices. Classification and regression tree (CART) analysis was used to identify barriers to and facilitators of screening among women with positive and negative perceptions. Nearly one-third of the cohort had inconsistent perceptions and practices: 37.4% had positive perceptions and were not having mammograms; 27.6% had negative/neutral perceptions and were having mammograms. Regardless of perceptions, a recent physician's recommendation for mammography, age ≥ 40, and interest in routine health care were universally associated with mammography practices. For women with positive perceptions and a physician's recommendation, barriers to screening included high acceptance coping, low active-planning coping, and high internal health locus of control. For women with negative perceptions, acknowledging the importance of asymptomatic screening was associated with mammography.

Baseline data from a population-based sample of 259 primary care physicians were used to examine the interrelations of 3 central constructs of the Transtheoretical Model of Change (TTM; stages of change, self-efficacy, and decisional balance) in regard to smoking cessation counseling behavior. In this article we explore the potential use of the TTM for future interventions to help understand and guide physicians' behavior change toward increasing adoption of smoking cessation interventions with their patients. It was hypothesized that self-efficacy and the decisional balance of counseling would be significantly related to physicians' stages of change, which in turn would be related to self-reported physician counseling behavior. Principal components analyses were conducted to examine the self-efficacy and decisional balance constructs. Coefficient alphas were.90 for self-efficacy and.84 and.78 for the pros and cons scales, respectively. Consistent with the TTM, analyses of variance revealed that later stages of physicians' readiness to provide smoking cessation counseling were associated with higher self-efficacy scores. Earlier stages showed significantly higher cons and lower pros of smoking cessation counseling. Structural equation modeling procedures supported the hypothesized path analysis model in which 3 constructs related to stage of readiness, which in turn related to reported physicians' counseling behavior.