Dynamics of Helping Behavior and Networks in a Small World

To investigate an effect of social interaction on the bystanders' intervention in emergency situations a rescue model was introduced which includes the effects of the victim's acquaintance with bystanders and those among bystanders from a network perspective. This model reproduces the experimental result that the helping rate (success rate in our model) tends to decrease although the number of bystanders $k$ increases. And the interaction among homogeneous bystanders results in the emergence of hubs in a helping network. For more realistic consideration it is assumed that the agents are located on a one-dimensional lattice (ring), then the randomness $p \in [0,1]$ is introduced: the $kp$ random bystanders are randomly chosen from a whole population and the $k-kp$ near bystanders are chosen in the nearest order to the victim. We find that there appears another peak of the network density in the vicinity of $k=9$ and $p=0.3$ due to the cooperative and competitive interaction between the near and random bystanders.Comment: 13 pages, 8 figure

Comprehensive Simultaneous Shipboard and Airborne Characterization of Exhaust from a Modern Container Ship at Sea

We report the first joint shipboard and airborne study focused on the chemical composition and water-uptake behavior of particulate ship emissions. The study focuses on emissions from the main propulsion engine of a Post-Panamax class container ship cruising off the central coast of California and burning heavy fuel oil. Shipboard sampling included micro-orifice uniform deposit impactors (MOUDI) with subsequent off-line analysis, whereas airborne measurements involved a number of real-time analyzers to characterize the plume aerosol, aged from a few seconds to over an hour. The mass ratio of particulate organic carbon to sulfate at the base of the ship stack was 0.23 ± 0.03, and increased to 0.30 ± 0.01 in the airborne exhaust plume, with the additional organic mass in the airborne plume being concentrated largely in particles below 100 nm in diameter. The organic to sulfate mass ratio in the exhaust aerosol remained constant during the first hour of plume dilution into the marine boundary layer. The mass spectrum of the organic fraction of the exhaust aerosol strongly resembles that of emissions from other diesel sources and appears to be predominantly hydrocarbon-like organic (HOA) material. Background aerosol which, based on air mass back trajectories, probably consisted of aged ship emissions and marine aerosol, contained a lower organic mass fraction than the fresh plume and had a much more oxidized organic component. A volume-weighted mixing rule is able to accurately predict hygroscopic growth factors in the background aerosol but measured and calculated growth factors do not agree for aerosols in the ship exhaust plume. Calculated CCN concentrations, at supersaturations ranging from 0.1 to 0.33%, agree well with measurements in the ship-exhaust plume. Using size-resolved chemical composition instead of bulk submicrometer composition has little effect on the predicted CCN concentrations because the cutoff diameter for CCN activation is larger than the diameter where the mass fraction of organic aerosol begins to increase significantly. The particle number emission factor estimated from this study is 1.3 × 10^(16) (kg fuel)^(−1), with less than 1/10 of the particles having diameters above 100 nm; 24% of particles (>10 nm in diameter) activate into cloud droplets at 0.3% supersaturation

A Diastereodivergent Synthetic Strategy for the Syntheses of Communesin F and Perophoramidine

An efficient, unified, and stereodivergent approach toward communesin F and perophoramidine was examined. The C(3) all-carbon quaternary center of an oxindole was smoothly constructed by base-promoted indolone-malonate alkylation chemistry. The complementary relative stereochemistry of the crucial vicinal quaternary centers found in communesin F and perophoramidine was selectively installed by substrate-controlled decarboxylative allylic alkylations

Housing consumption patterns and earnings behaviour of income support recipients over time

This study being conducted by the AHURI Queensland Research Centre is concerned with the 'housing pathways', earnings patterns, and 'life circumstances' of income support recipients. The research is based on analysis of longitudinal income support data from the Australian Government. The four main themes for the research concern: The housing arrangements and circumstances of income support recipients over time The relationships between changes in tenure and changes in incomes for these households or individuals; The relationship between changes in tenure and other changes in the characteristics or circumstances of income support recipients; and How the relationships and arrangements between housing and other factors vary by discrete groups of income support recipient

Plantar tactile perturbations enhance transfer of split-belt locomotor adaptation

Patterns of human locomotion are highly adaptive and flexible and depend on the environmental context. Locomotor adaptation requires the use of multisensory information to perceive altered environmental dynamics and generate an appropriate movement pattern. In this study, we investigated the use of multisensory information during locomotor learning. Proprioceptive perturbations were induced by vibrating tactors, placed bilaterally over the plantar surfaces. Under these altered sensory conditions, participants were asked to perform a split-belt locomotor task representative of motor learning. Twenty healthy young participants were separated into two groups: no-tactors (NT) and tactors (TC). All participants performed an overground walking trial, followed by treadmill walking including 18 min of split-belt adaptation and an overground trial to determine transfer effects. Interlimb coordination was quantified by symmetry indices and analyzed using mixed repeated-measures ANOVAs. Both groups adapted to the locomotor task, indicated by significant reductions in gait symmetry during the split-belt task. No significant group differences in spatiotemporal and kinetic parameters were observed on the treadmill. However, significant group differences were observed overground. Step and swing time asymmetries learned on the split-belt treadmill were retained and decayed more slowly overground in the TC group whereas in NT, asymmetries were rapidly lost. These results suggest that tactile stimulation contributed to increased lower limb proprioceptive gain. High proprioceptive gain allows for more persistent overground after effects, at the cost of reduced adaptability. Such persistence may be utilized in populations displaying pathologic asymmetric gait by retraining a more symmetric pattern

Basal and inducible anti-inflammatory epoxygenase activity in endothelial cells

The roles of CYP lipid-metabolizing pathways in endothelial cells are poorly understood. Human endothelial cells expressed CYP2J2 and soluble epoxide hydrolase (sEH) mRNA and protein. The TLR-4 agonist LPS (1 μg/ml; 24 h) induced CYP2J2 but not sEH mRNA and protein. LC–MS/MS analysis of the stable commonly used human endothelial cell line EA.Hy926 showed active epoxygenase and epoxide hydrolase activity: with arachidonic acid (stable epoxide products 5,6-DHET, and 14,15-DHET), linoleic acid (9,10-EPOME and 12,13-EPOME and their stable epoxide hydrolase products 9,10-DHOME and 12,13-DHOME), docosahexaenoic acid (stable epoxide hydrolase product 19,20-DiHDPA) and eicosapentaenoic acid (stable epoxide hydrolase product 17,18-DHET) being formed. Inhibition of epoxygenases using either SKF525A or MS-PPOH induced TNFα release, but did not affect LPS, IL-1β, or phorbol-12-myristate-13-acetate (PMA)-induced TNFα release. In contrast, inhibition of soluble epoxide hydrolase by AUDA or TPPU inhibited basal, LPS, IL-1β and PMA induced TNFα release, and LPS-induced NFκB p65 nuclear translocation. In conclusion, human endothelial cells contain a TLR-4 regulated epoxygenase CYP2J2 and metabolize linoleic acid > eicosapentaenoic acid > arachidonic acid > docosahexaenoic acid to products with anti-inflammatory activity

Smooth-filamental transition of active tracer fields stirred by chaotic advection

The spatial distribution of interacting chemical fields is investigated in the non-diffusive limit. The evolution of fluid parcels is described by independent dynamical systems driven by chaotic advection. The distribution can be filamental or smooth depending on the relative strength of the dispersion due to chaotic advection and the stability of the chemical dynamics. We give the condition for the smooth-filamental transition and relate the H\"older exponent of the filamental structure to the Lyapunov exponents. Theoretical findings are illustrated by numerical experiments.Comment: 4 pages, 3 figure