Experimental abatement data of underflow baffles for removal of floatables in the CSOs of the Greater Montréal (Canada) area.

Underflow baffles have gained in popularity over the years as a viable mean to intercept floatables in Combined Sewer Overflows (CSOs). This choice was mainly justified by the extremely low capital cost (CAPEX) and operational cost (OPEX) of this solution, although the efficiency of underflow baffles has never been clearly proven. The only similar application to underflow baffles are scum boards in grit chambers and clarifier. However, the flow conditions at CSOs vary considerably from those in grit chambers and clarifier. For this reason, review of the behavior of floatables in a rapid flow is paramount. Only then can comprehensive design criteria for underflow baffles and overflow chambers be suggested. Pilot scale tests, performed in a 17 metres long basin at various flowrates, had already shown that a critical horizontal velocity for floatables (Vcr) may develop in the overflow chambers. In this follow up study, the fate of intercepted floatables was investigated. It appears from this latest data that permanent capture of floatables decreases rapidly with an increase in the horizontal velocity of the flow, no matter what the baffle depth. Baffle depth increases capture at lower velocities (0.17 m/s) but become irrelevant at higher velocities (0.61 m/s). This data suggests that capture efficiency of existing underflow baffles in overflow chambers can be, at best, very low whenever the horizontal velocity increases above 0.30 m/s or 1 ft/s.     

Effects of lung volume and fatigue on evoked diaphragmatic phonomyogram in normal subjects

BACKGROUND: A diaphragmatic phonomyogram (PMG) evoked by maximal phrenic nerve stimulation at end expiratory lung volume (FRC) has been previously described as a good index of changes in diaphragmatic contractility with fatigue. A study was undertaken to assess whether this conclusion could be extended to different lung volumes. METHODS: Diaphragmatic compound motor action potentials (CMAPs) were recorded on each side of the chest by the means of surface electrodes placed over the eight intercostal spaces in five healthy subjects. Diaphragmatic PMGs from both sides were recorded with condenser microphones fixed to the skin close to the CMAP recording electrodes. Oesophageal and gastric balloon tipped catheters were employed to measure transdiaphragmatic pressure twitches (TwPDI) which served as the standard measure of changes in diaphragmatic contractility. PMG and TwPDI responses were compared at different lung volumes over inspiratory capacity both before and after fatiguing inspiratory resistive loading. RESULTS: No consistent relationship was found in different subjects or on different days in the same subject between PMG and lung volume or between PMG and TwPDI. However, the PMG:CMAP ratio from both sides at any given lung volume decreased after fatigue in roughly the same proportion as the TwPDI. CONCLUSIONS: These results show that, although PMG can detect changes in diaphragmatic contractility caused by fatigue in normal subjects, lung volume changes need to be controlled and each subject should serve as his or her own control.     

Suburethral sling urethropexy: a vaginal approach

The present study investigated the effects of ethanol withdrawal after its chronic administration on endogenous opioid systems in the nucleus accumbens of rats. An in situ hybridization study showed an increase in the prodynorphin mRNA level at 24 and 48 h (by 189 and 146%, respectively) after ethanol withdrawal, whereas the proenkephalin mRNA level remained unchanged. Furthermore, after a 48 h withdrawal period, the level of alpha-neoendorphin (alphaNEO), a prodynorphin-derived peptide, was significantly decreased (by 48%), that effect being associated with the enhancement of the K+-stimulated release of that peptide from nucleus accumbens slices. At 96 h after ethanol withdrawal, only the basal release of alphaNEO was elevated, while other parameters returned to the control level. Our data indicate that after 48 h of ethanol withdrawal, prodynorphin neurons are highly activated. The increased supply of endogenous kappa opioid receptor agonists in the nucleus accumbens at that time may promote aversive states during ethanol withdrawal.     

Restoration of stormwater retention capacity at the allotment-scale through a novel economic instrument

Urbanisation results in changes to runoff behaviour which, if not addressed, inevitably degrade receiving waters. To date, most stormwater management has focussed on the streetscape and public open space. Given that much of the catchment imperviousness is located on private land, we developed and tested a novel economic instrument (a uniform price auction) for encouraging allotment-scale stormwater retention. We evaluated bids using an integrated environmental benefit index (EBI), based on the ability of the proposed works to reduce runoff frequency, pollutant loads and to reduce potable water demand. The uniform price auction resulted in 1.4 ha of impervious areas being effectively 'disconnected' from the stormwater system. The EBI provided an objective and transparent method of comparing bids, which varied in the type of works proposed (e.g. rainwater tank, rain-garden), the cost and the resulting environmental benefit. Whilst the pilot auction was a success, the public subsidy of works undertaken was around 85%, meaning that property owners a relatively small private benefit in the works. Future auction rounds will be revised to (i) test an EBI which is more focussed on the protection of streams (assessing changes to runoff frequency, baseflow volumes and water quality) and (ii) provide an auction process which is simpler to understand, and provides greater practical support for landholders who wish to undertake works.     

High Figure of Merit (FOM) of Bragg Modes in Au‐Coated Nanodisk Arrays for Plasmonic Sensing

Gold‐coated nanodisk arrays of nearly micron periodicity are reported that have high figure of merit (FOM) and sensitivity necessary for plasmonic refractometric sensing, with the added benefit of suitability for surface‐enhanced Raman scattering (SERS), large‐scale microfabrication using standard photolithographic techniques and a simple instrumental setup. Gold nanodisk arrays are covered with a gold layer to excite the Bragg modes (BM), which are the propagative surface plasmons localized by the diffraction from the disk array. This generates surface‐guided modes, localized as standing waves, leading to highly confined fields confirmed by a mapping of the SERS intensity and numerical simulations with 3D finite element method. The optimal gold‐coated nanodisk arrays are applied for refractometric sensing in transmission spectroscopy with better performance than nanohole arrays and they are integrated to a 96‐well plate reader for detection of IgY proteins in the nanometer range in PBS. The potential for sensing in biofluids is assessed with IgG detection in 1:1 diluted urine. The structure exhibits a high FOM of up to 46, exceeding the FOM of structures supporting surface plasmon polaritons and comparable to more complex nanostructures, demonstrating that subwavelength features are not necessary for high‐performance plasmonic sensing.     

Is computational complexity a barrier to manipulation?

When agents are acting together, they may need a simple mechanism to decide on joint actions. One possibility is to have the agents express their preferences in the form of a ballot and use a voting rule to decide the winning action(s). Unfortunately, agents may try to manipulate such an election by mis-reporting their preferences. Fortunately, it has been shown that it is NP-hard to compute how to manipulate a number of different voting rules. However, NP-hardness only bounds the worst-case complexity. In this survey article, we summarize the evidence for and against computational complexity being a barrier to manipulation. We look both at techniques identified to increase complexity (for example, hybridizing together two or more voting rules), as well as other features that may change the computational complexity of computing a manipulation (for example, if votes are restricted to be single peaked then some of the complexity barriers fall away). We discuss recent theoretical results that consider the average case, as well as simple greedy and approximate methods. We also describe how computational ??phase transitions??, which have been fruitful in identifying hard instances of propositional satisfiability and other NP-hard problems, have provided insight into the hardness of manipulating voting rules in practice. Finally, we consider manipulation of other related problems like stable marriage and tournament problems.     

Investigating the influence of age,social capital affinity,and flow on positive outcomes reported by e-commerce site users

This study investigated the role of social capital affinity (the sense of community and likeness felt for people online) and the experience of flow (concentrated engagement in/enjoyment of an activity) as antecedents to a variety of positive outcomes associated with the use of e-commerce sites. Also, based on socio-emotional selectivity theory, the current study assessed the influence of age on social capital affinity and flow. As a subset of data from a telephone sample of Internet users in the USA, 282 e-commerce users responded to questions about site satisfaction, perceived focused and incidental knowledge-gains, and affirmation, in addition to flow and social capital affinity. As predicted by socio-emotional selectivity theory, there was a negative relationship between age and social capital affinity and flow. Flow, for its part, mediated the effects of age and social capital affinity on perceived focused and incidental knowledge-gain, satisfaction and affirmation among participants reporting e-commerce use. Finally, the current results indicated that satisfaction and perceived incidental learning predicted participant affirmation for their chosen e-commerce site.     

Flexible Image-Based Photometric Reconstruction using Virtual Light Sources

Photometric reconstruction is the process of estimating the illumination and surface reflectance properties of an environment, given a geometric model of the scene and a set of photographs of its surfaces. For mixed-reality applications, such data is required if synthetic objects are to be correctly illuminated or if synthetic light sources are to be used to re-light the scene. Current methods of estimating such data are limited in the practical situations in which they can be applied, due to the fact that the geometric and radiometric models of the scene which are provided by the user must be complete, and that the position (and in some cases, intensity) of the light sources must also be specified a-priori. In this paper, a novel algorithm is presented which overcomes these constraints, and allows photometric data to be reconstructed in less restricted situations. This is achieved through the use of virtual light sources which mimic the effect of direct illumination from unknown luminaires, and indirect illumination reflected off unknown geometry. The intensity of these virtual light sources and the surface material properties are estimated using an iterative algorithm which attempts to match calculated radiance values to those observed in photographs. Results are presented for both synthetic and real scenes that show the quality of the reconstructed data and its use in off-line mixed-reality applications.     

Occlusion pressures in men rebreathing CO2 under methoxyflurane anesthesia

The effect of general anesthesia on control of breathing was studied by CO2 rebreathing and occlusion pressure measurements in six normal human subjects under methoxyflurane anesthesia. CO2 was found to increase the amplitude of the occlusion pressure wave without changing its shape, so that CO2 responses in terms of the occlusion pressure developed 100 ms after the onset of inspiration (Po/0.1) gave results equivalent to the responses in terms of Po/1.o or any other parameter of the pressure wave. Methoxyflurane depressed the ventilatory response to CO2 but not the occlusion pressure response, implying that the most important action of the anesthetic was to increase the effective elastance of the respiratory system rather than to depress the respiratory centers. The elastance was further increased by CO2, and this mechanical change had the effect of shifting the "apneic threshold" extrapolated from the ventilatory response curve to a lower PAco2. Frequency of breathing, inspiratory and expiratory times were not altered by CO2 in anesthetized subjects.