High fidelity sorting of remarkably similar components via metal-mediated assembly.

Subtle differences in ligand coordination angle and rigidity lead to high fidelity sorting between individual components displaying identical coordination motifs upon metal-mediated self-assembly. Narcissistic self-sorting can be achieved between highly similar ligands that vary minimally in rigidity and internal coordination angle upon combination with Fe(ii) ions and 2-formylpyridine. Selective, sequential cage formation can be precisely controlled in a single flask from a mix of three different core ligands (and 33 total components) differing only in the hybridization of one group that is uninvolved in the metal coordination process

Tropospheric ozone in the western Pacific Rim: Analysis of satellite and surface-based observations along with comprehensive 3-D model simulations

Tropospheric ozone production and transport in mid-latitude eastern Asia is studied. Data analysis of surface-based ozone measurements in Japan and satellite-based tropospheric column measurements of the entire western Pacific Rim are combined with results from three-dimensional model simulations to investigate the diurnal, seasonal and long-term variations of ozone in this region. Surface ozone measurements from Japan show distinct seasonal variation with a spring peak and summer minimum. Satellite studies of the entire tropospheric column of ozone show high concentrations in both the spring and summer seasons. Finally, preliminary model simulation studies show good agreement with observed values

Mixing by microorganisms in stratified fluids

We examine the vertical mixing induced by the swimming of microorganisms at low Reynolds and Péclet numbers in a stably stratified ocean, and show that the global contribution of oceanic microswimmers to vertical mixing is negligible. We propose two approaches to estimating the mixing efficiency, η, or the ratio of the rate of potential energy creation to the total rate-of-working on the ocean by microswimmers. The first is based on scaling arguments and estimates η in terms of the ratio between the typical organism size, a, and an intrinsic length scale for the stratified flow, l = (νκ/N2)1/4, where ν is the kinematic viscosity, κ the diffusivity, and N the buoyancy frequency. In particular, for small organisms in the relevant oceanic limit, a/l \u3c\u3c 1, we predict the scaling η ∼ (a/l)3. The second estimate of η is formed by solving the full coupled flow-stratification problem by modeling the swimmer as a regularized force dipole, and computing the efficiency numerically. Our computational results, which are examined for all ratios a/l, validate the scaling arguments in the limit a/l \u3c\u3c 1 and further predict η ≈ 1.2(a/l)3 for vertical swimming and η ≈ 0.15 (a/l)3 for horizontal swimming. These results, relevant for any stratified fluid rich in biological activity, imply that the mixing efficiency of swimming microorganisms in the ocean is at very most 8% and is likely smaller by at least two orders of magnitude

Individual Differences in Dopamine Are Associated with Reward Discounting in Clinical Groups But Not in Healthy Adults.

Some people are more willing to make immediate, risky, or costly reward-focused choices than others, which has been hypothesized to be associated with individual differences in dopamine (DA) function. In two studies using PET imaging, one empirical (Study 1: N = 144 males and females across 3 samples) and one meta-analytic (Study 2: N = 307 across 12 samples), we sought to characterize associations between individual differences in DA and time, probability, and physical effort discounting in human adults. Study 1 demonstrated that individual differences in DA D2-like receptors were not associated with time or probability discounting of monetary rewards in healthy humans, and associations with physical effort discounting were inconsistent across adults of different ages. Meta-analytic results for temporal discounting corroborated our empirical finding for minimal effect of DA measures on discounting in healthy individuals but suggested that associations between individual differences in DA and reward discounting depend on clinical features. Addictions were characterized by negative correlations between DA and discounting, but other clinical conditions, such as Parkinson's disease, obesity, and attention-deficit/hyperactivity disorder, were characterized by positive correlations between DA and discounting. Together, the results suggest that trait differences in discounting in healthy adults do not appear to be strongly associated with individual differences in D2-like receptors. The difference in meta-analytic correlation effects between healthy controls and individuals with psychopathology suggests that individual difference findings related to DA and reward discounting in clinical samples may not be reliably generalized to healthy controls, and vice versa.SIGNIFICANCE STATEMENT Decisions to forgo large rewards for smaller ones due to increasing time delays, uncertainty, or physical effort have been linked to differences in dopamine (DA) function, which is disrupted in some forms of psychopathology. It remains unclear whether alterations in DA function associated with psychopathology also extend to explaining associations between DA function and decision making in healthy individuals. We show that individual differences in DA D2 receptor availability are not consistently related to monetary discounting of time, probability, or physical effort in healthy individuals across a broad age range. By contrast, we suggest that psychopathology accounts for observed inconsistencies in the relationship between measures of DA function and reward discounting behavior

Antibiotic resistant bacteria in the Hudson River Estuary linked to wet weather sewage contamination

Heterotrophic bacteria resistant to tetracycline and ampicillin were assessed in waterways of the New York City metropolitan area using culture-dependent approaches and 16S rRNA gene sequence analysis of resultant isolates. Resistant microbes were detected at all 10 sampling sites in monthly research cruises on the lower Hudson River Estuary (HRE), with highest concentrations detected at nearshore sites. Higher frequency sampling was conducted in Flushing Bay, to enumerate resistant microbes under both dry and wet weather conditions. Concentrations of ampicillin- and tetracycline- resistant bacteria, in paired samples, were positively correlated with one another and increased following precipitation. Counts of the fecal indicator, Enterococcus, were positively correlated with levels of resistant bacteria, suggesting a shared sewage-associated source. Analysis of 16S rRNA from isolates identified a phylogenetically diverse group of resistant bacteria, including genera containing opportunistic pathogens. The occurrence of Enterobacteriaceae, a family of enteric bacteria, was found to be significantly higher in resistant isolates compared to total heterotrophic bacteria and increased following precipitation. This study is the first to document the widespread distribution of antibiotic-resistant bacteria in the HRE and to demonstrate clearly a link between the abundance of antibiotic-resistant bacteria and levels of sewage-associated bacteria in an estuary

Determinants of Bacterial Contamination in Pools, Spas, and Wading Pools: Should Chlorine Standards Be Revised?

Using a retrospective case-control study, we compared poolside tests with bacteriological samples during three consecutive summers. A total of 844 matched samples were obtained. Increased chlorine levels were associated with lower rates of contamination. Alkalinity, pH, and TDS were not statistically associated with bacteriological failures. In swimming pools with \u3e 1 ppm of chlorine, 27/30 (90.0%) passed bacteriologic evaluation. In spas with \u3c 1.0 ppm of chlorine, only 12/28 (42.9%) passed. Of the spas with \u3e 3.0 ppm of chlorine, 170/176 (96.6%) passed. Of the wading pools with \u3c 1ppm of chlorine, only 12/25 (48.0%) passed. Of the wading pools with \u3e 2 ppm, 263/290 (90.7%) passed. Of available poolside tests, only chlorine levels are predictive of positive testing for fecal contamination. Higher levels of chlorine were associated with higher passing rates. Current standards for disinfection in spas and wading pools may need to be increased to help prevent contamination

The politics of impunity: a study of journalists’ experiential accounts of impunity in Bulgaria, Democratic Republic of Congo, India, Mexico and Pakistan

Definitions of impunity regarding crimes against journalists have thus far been too narrow. Therefore we propose a new approach to understanding impunity as also being grounded in journalists’ lived reality and perceptions to better understand the complexity and breadth of impunity. It is based on the findings obtained through a set of semi-structured interviews with 40 editors and senior journalists in five countries and expressed in a new typology of impunity. We argue that what we call the ‘Politics of Impunity’ is a policy of governance whereby impunity is used as a political tool by the state and state-sponsored actors to achieve journalistic self-censorship. This is done through the deliberate deprivation of private autonomy brought about by the enforced exile of journalists into a ‘space of exception’ where they are both within and beyond the law. The exercise of the ‘Politics of Impunity’ in an increasing number of states creates an environment that only allows for politically compliant journalism

Wood dynamics in headwater streams of the Colorado Rocky Mountains

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