Numerical simulation of the airflow–rivulet interaction associated with the rain-wind induced vibration phenomenon

Rain-wind induced vibration is an aeroelastic phenomenon that occurs on the inclined cables of cable-stayed bridges. The vibrations are believed to be caused by a complicated nonlinear interaction between rivulets of rain water that run down the cables and the wind loading on the cables due to the unsteady aerodynamic flow field. Recent research at the University of Strathclyde has been to develop a numerical method to simulate the influence of the external air flow on the rivulet dynamics and vice versa, the results of which can be used to assess the importance of the water rivulets on the instability. The numerical approach for the first time couples a Discrete Vortex Method solver to determine the external flow field and unsteady aerodynamic loading, and a pseudo-spectral solver based on lubrication theory to model the evolution and growth of the water rivulets on the cable surface under external loading. The results of the coupled model are used to assess the effects of various loading combinations, and importantly are consistent with previous full scale and experimental observations of rain-wind induced vibration, providing new information about the underlying physical mechanisms of the instability

Developing preparedness for flexible delivery of training in enterprises

On a basis of research and literature review, Smith, in 2001, suggested a model for the development of preparedness of learners and their workplaces to support the flexible delivery of training in enterprises. Using the model as a framework, he then developed a detailed set of strategies that may be used in operating workplaces to develop learners and workplaces for effective flexible delivery. The research reported here was designed to test that strategy set in 12 different enterprises to assess the feasibility of their implementation in operating workplaces. The research shows that a majority of suggested strategies are feasible for implementation; some are feasible with qualification; and a minority were not seen as feasible.<br /

Timing verification of dynamically reconfigurable logic for Xilinx Virtex FPGA series

This paper reports on a method for extending existing VHDL design and verification software available for the Xilinx Virtex series of FPGAs. It allows the designer to apply standard hardware design and verification tools to the design of dynamically reconfigurable logic (DRL). The technique involves the conversion of a dynamic design into multiple static designs, suitable for input to standard synthesis and APR tools. For timing and functional verification after APR, the sections of the design can then be recombined into a single dynamic system. The technique has been automated by extending an existing DRL design tool named DCSTech, which is part of the Dynamic Circuit Switching (DCS) CAD framework. The principles behind the tools are generic and should be readily extensible to other architectures and CAD toolsets. Implementation of the dynamic system involves the production of partial configuration bitstreams to load sections of circuitry. The process of creating such bitstreams, the final stage of our design flow, is summarized

Individual cognitive-behavioural anger treatment for people with mild-borderline intellectual disabilities and histories of aggression: a controlled trial

Objectives - Anger is a significant predictor and activator of violent behaviour in patients living in institutional settings. There is some evidence for the value of cognitive-behavioural treatments for anger problems with people with intellectual disabilities. In this study, a newly designed treatment targeted at anger disposition, reactivity, and control was provided to intellectually disabled offenders with aggression histories living in secure settings. Design - About forty detained patients with mild-borderline intellectual disabilities and histories of serious aggression were allocated to specially modified cognitive-behavioural anger treatment (AT group) or to routine care waiting-list control (RC group) conditions. Methods - AT group participants received 18 sessions of individual treatment. The AT and RC groups were assessed simultaneously at 4 time points: screen, pre- and post-treatment, and at 4-month follow-up using a range of self- and staff-rated anger measures. The effectiveness of the treatment was evaluated using ANCOVA linear trend analyses of group differences on the main outcome measures. Results - The AT group's self-reported anger scores on a number of measures were significantly lower following treatment, compared with the RC wait-list condition, and these improvements were maintained at follow-up. Limited evidence for the effectiveness of treatment was provided by staffs' ratings of patient behaviour post-treatment. Conclusions - Detained men with mild-moderate intellectual disabilities and histories of severe aggression can successfully engage in, and benefit from, an intensive individual cognitive-behavioural anger treatment that also appears to have beneficial systemic effects

Effect of visit-to-visit variation of heart rate and systolic blood pressure on outcomes in chronic systolic heart failure: results from the Systolic Heart Failure Treatment With the If Inhibitor Ivabradine Trial (SHIFT) trial

Background: Elevated resting heart rate (HR) and low systolic blood pressure (SBP) are related to poor outcomes in heart failure (HF). The association between visit-to-visit variation in SBP and HR and risk in HF is unknown. Methods and Results: In Systolic Heart Failure Treatment with the If inhibitor ivabradine Trial (SHIFT) patients, we evaluated relationships between mean HR, mean SBP, and visit-to-visit variations (coefficient of variation [CV]=SD/mean×100%) in SBP and HR (SBP-CV and HR-CV, respectively) and primary composite endpoint (cardiovascular mortality or HF hospitalization), its components, all-cause mortality, and all-cause hospitalization. High HR and low SBP were closely associated with risk for primary endpoint, all-cause mortality, and HF hospitalization. The highest number of primary endpoint events occurred in the highest HR tertile (38.8% vs 16.4% lowest tertile; P&lt;0.001). For HR-CV, patients at highest risk were those in the lowest tertile. Patients in the lowest thirds of mean SBP and SBP-CV had the highest risk. The combination of high HR and low HR-CV had an additive deleterious effect on risk, as did that of low SBP and low SBP-CV. Ivabradine reduced mean HR and increased HR-CV, and increased SBP and SBP-CV slightly. Conclusions: Beyond high HR and low SBP, low HR-CV and low SBP-CV are predictors of cardiovascular outcomes with additive effects on risk in HF, but with an unknown effect size. Beyond HR reduction, ivabradine increases HR-CV. Low visit-to-visit variation of HR and SBP might signal risk of cardiovascular outcomes in systolic HF. Clinical Trial Registration: URL: http://www.isrctn.com/. Unique identifier: ISRCTN70429960

Raising Permutations to Powers in Place

Given a permutation of n elements, stored as an array, we address the problem of replacing the permutation by its kth power. We aim to perform this operation quickly using o(n) bits of extra storage. To this end, we first present an algorithm for inverting permutations that uses O(lg^2 n) additional bits and runs in O(n lg n) worst case time. This result is then generalized to the situation in which the permutation is to be replaced by its kth power. An algorithm whose worst case running time is O(n lg n) and uses O(lg^2 n + min{k lg n, n^{3/4 + epsilon}}) additional bits is presented

Reclaiming Lost Territory: The Response of Owyhee Harvester Ants to Forager Intrusions by Neighboring Colonies

Neighboring colonies of the Owyhee harvester ant, Pogonomyrmex salinus, often share nonoverlapping foraging boundaries in the areas between their nests. We found that interactions between neighbors along these foraging boundaries were infrequent but peaceful, and usually resulted in one or both individuals becoming agitated and scurrying away in opposite directions. Interactions between neighbors were necessary to maintain the foraging ranges of their respective colonies. An exclusion experiment showed that when one colony of a pair situated 5-7 m apart was denied access to its foraging range, individuals from the other colony would usually (i.e., in 7 out of 10 cases) enter the unoccupied space within one day. In 6 of 7 of those cases the occupiers set up foraging trails in the newly acquired area in 5 to 39 days (median = 13 days). When foragers from the excluded colony were subsequently allowed access to their original foraging area, theyreclaimed the entire area within 11 days but did not extend their advances beyond the original foraging boundaries. In contrast to the earlier encounters between neighbors, encounters during the reacquisition period were always aggressive, and in 14 of 57 encounters one or both of the combatants was killed. Non-lethal contests were shorter duration than lethal contests (19±2 s versus 422±65 s, respectively). Our results show that competition for foraging space in Owyhee harvester ants is intense despite the seemingly peaceful relationship between neighboring colonies prior to perturbation of their foraging boundaries

Smartphone Applications Utilizing Biofeedback Can Aid Stress Reduction

Introduction: Stress is one of the leading global causes of disease and premature mortality. Despite this, interventions aimed at reducing stress have low adherence rates. The proliferation of mobile phone devices along with gaming-style applications allows for a unique opportunity to broaden the reach and appeal of stress-reduction interventions in modern society. We assessed the effectiveness of two smartphone applications games combined with biofeedback in reducing stress. Methods: We compared a control game to gaming-style smartphone applications combined with a skin conductance biofeedback device (the Pip). Fifty participants aged between 18 and 35 completed the Trier Social Stress Test. They were then randomly assigned to the intervention (biofeedback game) or control group (a non-biofeedback game) for thirty minutes. Perceived stress, heart rate and mood were measured before and after participants had played the games. Results: A mixed factorial ANOVA showed a significant interaction between time and game type in predicting perceived stress [F(1,48) = 14.19, p < 0.001]. Participants in the biofeedback intervention had significantly reduced stress compared to the control group. There was also a significant interaction between time and game in predicting heart rate [F(1,48) = 6.41, p < 0.05]. Participants in the biofeedback intervention showed significant reductions in heart rate compared to the control group. Discussion: This illustrates the potential for gaming-style smartphone applications combined with biofeedback as stress reduction interventions

Ventilation Performance and Hygrothermal Conditions in New-build UK Housing

Providing a high quality indoor environment is important to protect occupant’s health and well-being, particularly in the home where we spend a significant amount of time. This paper explores indoor environmental conditions in mechanically and naturally ventilated new-build low-energy housing in the UK. Indoor air temperature, relative humidity and carbon dioxide data were collated and analysed from 53 dwellings across 20 different new-build demonstration projects (consisting of public and private developments). The results raise concerns regarding ventilation performance in new-build homes, particularly homes with natural/mechanical extract ventilation (MEV). Significantly less variation of temperature and relative humidity levels were observed in homes with balanced mechanical ventilation with heat recovery systems (p=<0.001), suggesting these systems may help to provide a more stable indoor hygrothermal environment. Average indoor air relative humidity levels were consistently higher in MVHR dwellings. The findings suggest that the type of ventilation strategy can play a significant role in regulating indoor relative humidity and air temperature in new- build thermally efficient homes

Substrate Integrated Bragg Waveguide: an Octave-bandwidth Single-mode Functional Transmission-Line for Millimeter-Wave and Terahertz Applications

We demonstrate an air-core single-mode hollow waveguide that uses Bragg reflector structures in place of the vertical metal walls of the standard rectangular waveguide or via holes of the so-called substrate integrated waveguide. The high-order modes in the waveguide are substantially suppressed by a modal-filtering effect, making the waveguide operate in the fundamental mode over more than one octave. Numerical simulations show that the propagation loss of the proposed waveguide can be lower than that of classic hollow metallic rectangular waveguides at terahertz frequencies, benefiting from a significant reduction in Ohmic loss. To facilitate fabrication and characterization, a proof-of-concept 20 to 45 GHz waveguide is demonstrated, which verifies the properties and advantages of the proposed waveguide. A zero group-velocity dispersion point is observed at near the middle of the operating band. This work offers a step towards a novel hybrid transmission-line medium that can be used in a variety of functional components for broadband millimeter-wave and terahertz applications.Comment: 11 pages, 9 figures, journal articl