Front-loading Urban Stormwater Management for Success – A Perspective Incorporating Current Studies on the Implementation of Retrofit Low-impact Development

Recent work into the implementation of low-impact development (LID) suggests that a decentralized, source-control approach has the potential to significantly reduce urban stormwater runoff quantity. The practice of retrofit stormwater management is currently dominated by demonstration projects, and some additional momentum is required to spur adoption and upscaling of LID practices so that the scale of this management approach can better match the scale of disturbance. This momentum may be provided in part by targeted research into effectiveness of stormwater best management practices insofar as research accounts for cost and effectiveness (e.g., water quality benefits, and actual stormwater capture) under a variety of climate conditions. We posit that the factors of increasing public participation in stormwater management; engaging local agencies and non-governmental organizations (NGOs); application of proven source control methods to mitigate runoff formation; and science-based, comprehensive monitoring strategies are all important to the sustainable implementation of retrofit low-impact development. From the perspective of Federal researchers and local NGOs, this paper presents features, objectives, and costs of recent efforts to properly scale demonstration projects and broader LID initiatives. In order to realize the full benefits of decentralized LID stormwater management practices in urban and suburban areas, we conclude that a nexus must exist of a motivated and engaged citizenry, solid support from municipal and regional agencies, sound source control management practices, and follow-up monitoring to judge effectiveness

Effect of social status on behavioral and neural response to stress

Individuals respond differently to traumatic stress. Social status, which plays a key role in how animals experience and interact with their social environment, may influence how individuals respond to stressors. In this study, we used a conditioned defeat model to investigate whether social status alters susceptibility to the behavioral and neural consequences of traumatic stress. Conditioned defeat is a model in Syrian hamsters in which an acute social defeat encounter results in a long term increase in submissive behavior and a loss of normal territorial aggression. To establish social status, we weight matched and paired Syrian hamsters in daily aggressive encounters for two weeks to create dominant/subordinate relationships. We also included controls which were exposed daily to a clean empty cage for the same 14 day period. Twenty-four hours after the final pairing or empty cage exposure, subjects were divided into defeat and no defeat groups. Individuals in the defeat group received three 5 minute social defeats at 5 minute intervals in the cage of a larger aggressive hamster. Individuals in the no defeat group were exposed to the empty cage of a larger aggressive hamster at the same time intervals. In experiment 1, subjects of both groups were tested for conditioned defeat with a non-aggressive intruder 24 hours after social defeat training. In experiment 2, brains were collected 65 minutes following social defeat training and immunohistochemistry was performed for c-Fos protein, a marker of neural activation. We quantified the number of c-Fos immunopositive cells in brain regions known to be involved in stress and aggression, including the ventral medial prefrontal cortex, medial amygdala, and lateral and ventromedial hypothalamus. We found that subordinate animals showed significantly more conditioned defeat behavior than did dominants or controls, and subordinates showed significantly less c-Fos immunoreactivity than did dominants in all these brain regions. These results suggest that decreased neural activity in these brain regions corresponds to an increased susceptibility to conditioned defeat. In sum, social status plays an important role in how animals respond to social stressors and this corresponds to activity in specific brain areas

Sleep, circadian biology and skeletal muscle interactions : Implications for metabolic health

There currently exists a modern epidemic of sleep loss, triggered by the changing demands of our 21st century lifestyle that embrace ‘round-the-clock’ remote working hours, access to energy-dense food, prolonged periods of inactivity, and on-line social activities. Disturbances to sleep patterns impart widespread and adverse effects on numerous cells, tissues, and organs. Insufficient sleep causes circadian misalignment in humans, including perturbed peripheral clocks, leading to disrupted skeletal muscle and liver metabolism, and whole-body energy homeostasis. Fragmented or insufficient sleep also perturbs the hormonal milieu, shifting it towards a catabolic state, resulting in reduced rates of skeletal muscle protein synthesis. The interaction between disrupted sleep and skeletal muscle metabolic health is complex, with the mechanisms underpinning sleep-related disturbances on this tissue often multifaceted. Strategies to promote sufficient sleep duration combined with the appropriate timing of meals and physical activity to maintain circadian rhythmicity are important to mitigate the adverse effects of inadequate sleep on whole-body and skeletal muscle metabolic health. This review summarises the complex relationship between sleep, circadian biology, and skeletal muscle, and discusses the effectiveness of several strategies to mitigate the negative effects of disturbed sleep or circadian rhythms on skeletal muscle health

A Multiscale Approach to Blast Neurotrauma Modeling: Part I – Development of Novel Test Devices for in vivo and in vitro Blast Injury Models

The loading conditions used in some current in vivo and in vitro blast-induced neurotrauma models may not be representative of real-world blast conditions. To address these limitations, we developed a compressed-gas driven shock tube with different driven lengths that can generate Friedlander-type blasts. The shock tube can generate overpressures up to 650 kPa with durations between 0.3 and 1.1 ms using compressed helium driver gas, and peak overpressures up to 450 kPa with durations between 0.6 and 3 ms using compressed nitrogen. This device is used for short-duration blast overpressure loading for small animal in vivo injury models, and contrasts the more frequently used long duration/high impulse blast overpressures in the literature. We also developed a new apparatus that is used with the shock tube to recreate the in vivo intracranial overpressure response for loading in vitro culture preparations. The receiver device surrounds the culture with materials of similar impedance to facilitate the propagation of a single overpressure pulse through the tissue. This method prevents pressure waves reflecting off the tissue that can cause unrealistic deformation and injury. The receiver performance was characterized using the longest helium-driven shock tube, and produced in-fluid overpressures up to 1500 kPa at the location where a culture would be placed. This response was well correlated with the overpressure conditions from the shock tube (R2 = 0.97). Finite element models of the shock tube and receiver were developed and validated to better elucidate the mechanics of this methodology. A demonstration exposing a culture to the loading conditions created by this system suggest tissue strains less than 5% for all pressure levels simulated, which was well below functional deficit thresholds for strain rates less than 50 s−1. This novel system is not limited to a specific type of culture model and can be modified to reproduce more complex pressure pulses

How much is enough? Minimal responses of water quality and stream biota to partial retrofit stormwater management in a suburban neighborhood

Decentralized stormwater management approaches (e.g., biofiltration swales, pervious pavement, green roofs, rain gardens) that capture, detain, infiltrate, and filter runoff are now commonly used to minimize the impacts of stormwater runoff from impervious surfaces on aquatic ecosystems. However, there is little research on the effectiveness of retrofit, parcel-scale stormwater management practices for improving downstream aquatic ecosystem health. A reverse auction was used to encourage homeowners to mitigate stormwater on their property within the suburban, 1.8 km2 Shepherd Creek catchment in Cincinnati, Ohio (USA). In 2007–2008, 165 rain barrels and 81 rain gardens were installed on 30% of the properties in four experimental (treatment) subcatchments, and two additional subcatchments were maintained as controls. At the base of the subcatchments, we sampled monthly baseflow water quality, and seasonal (5×/year) physical habitat, periphyton assemblages, and macroinvertebrate assemblages in the streams for the three years before and after treatment implementation. Given the minor reductions in directly connected impervious area from the rain barrel installations (11.6% to 10.4% in the most impaired subcatchment) and high total impervious levels (13.1% to 19.9% in experimental subcatchments), we expected minor or no responses of water quality and biota to stormwater management. There were trends of increased conductivity, iron, and sulfate for control sites, but no such contemporaneous trends for experimental sites. The minor effects of treatment on streamflow volume and water quality did not translate into changes in biotic health, and the few periphyton and macroinvertebrate responses could be explained by factors not associated with the treatment (e.g., vegetation clearing, drought conditions). Improvement of overall stream health is unlikely without additional treatment of major impervious surfaces (including roads, apartment buildings, and parking lots). Further research is needed to define the minimum effect threshold and restoration trajectories for retrofitting catchments to improve the health of stream ecosystems

Numerical Ricci-flat metrics on K3

We develop numerical algorithms for solving the Einstein equation on Calabi-Yau manifolds at arbitrary values of their complex structure and Kahler parameters. We show that Kahler geometry can be exploited for significant gains in computational efficiency. As a proof of principle, we apply our methods to a one-parameter family of K3 surfaces constructed as blow-ups of the T^4/Z_2 orbifold with many discrete symmetries. High-resolution metrics may be obtained on a time scale of days using a desktop computer. We compute various geometric and spectral quantities from our numerical metrics. Using similar resources we expect our methods to practically extend to Calabi-Yau three-folds with a high degree of discrete symmetry, although we expect the general three-fold to remain a challenge due to memory requirements.Comment: 38 pages, 10 figures; program code and animations of figures downloadable from http://schwinger.harvard.edu/~wiseman/K3/ ; v2 minor corrections, references adde