Electron Accumulation Induces Efficiency Bottleneck for Hydrogen Production in Carbon Nitride Photocatalysts.

This study addresses the light intensity dependence of charge accumulation in a photocatalyst suspension, and its impact on both charge recombination kinetics and steady-state H2 evolution efficiency. Cyanamide surface functionalized melon-type carbon nitride (NCNCNx) has been selected as an example of emerging carbon nitrides photocatalysts because of its excellent charge storage ability. Transient spectroscopic studies (from ps to s) show that the bimolecular recombination of photogenerated electrons and holes in NCNCNx can be well described by a random walk model. Remarkably, the addition of hole scavengers such as 4-methylbenzyl alcohol can lead to ∼400-fold faster recombination kinetics (lifetime shortening to ∼10 ps). We show that this acceleration is not the direct result of ultrafast hole extraction by the scavenger, but is rather caused by long-lived electron accumulation in NCNCNx after hole extraction. The dispersive pseudo-first order recombination kinetics become controlled by the density of accumulated electrons. H2 production and steady-state spectroscopic measurements indicate that the accelerated recombination caused by electron accumulation limits the H2 generation efficiency. The addition of a reversible electron acceptor and mediator, methyl viologen (MV2+), accelerates the extraction of electrons from the NCNCNx and increases the H2 production efficiency under one sun irradiation by more than 30%. These results demonstrate quantitatively that while long-lived electrons are essential to drive photoinduced H2 generation in many photocatalysts, excessive electron accumulation may result in accelerated recombination losses and lower performance, and thus highlight the importance of efficient electron and hole extraction in enabling efficient water splitting photocatalysts.ERC AdG Intersolar grant (Grant No. 291482), The Christian Doppler Research Association The OMV Grou

Prompt letters to reduce non-attendance: applying evidence based practice

<p>Abstract</p> <p>Background</p> <p>Non-attendance rates in psychiatric outpatient clinics have been a topic of considerable interest. It is measured as an indicator of quality of service provision. Failed attendances add to the cost of care as well as having an adverse impact on patients leading to missing medications, delay in identifying relapses and increasing waiting list time. Recent trials have demonstrated that prompting letters sent to patients led to a decrease in non-attendance rates. We applied this evidence based practice in our community mental health setting to evaluate its impact.</p> <p>Methods</p> <p>Using a before and after study design, we sent prompting letters to all patients due to attend outpatient clinic appointments for a period of six months in 2007. Non-attendance rates were compared with the corresponding period in 2006. We also looked at trends of non-attendance prior to this intervention and compared results with other parts of our service where this intervention had not been applied.</p> <p>Results</p> <p>1433 prompting letters were sent out to all out-patient appointments made from June to November 2007. This resulted in an average non-attendance rate of 17% which was significantly less compared to 27% between June and November 2006 (RR 0.65, 95% CI 0.56 to 0.76, NNT 11). No downward trend in non-attendance rate was identified either prior to the intervention or when compared with similar teams across the city.</p> <p>Conclusion</p> <p>Prompt letters have been shown to reduce non-attendance rates in previous RCTs and systematic reviews. Our findings demonstrate a reduction in non-attendance rates with prompting letters even under non-trial conditions. Majority of the patients were constant during the two periods compared although there were some changes in medical personnel. This makes it difficult to attribute all the change, solely to the intervention alone. Perhaps our work shows that the results of pragmatic randomised trials are easily applicable and produce similar results in non-randomised settings. We found that prompting letters are a useful and easy to apply evidence based intervention to reduce non-attendance rates with a potential to achieve significant cost savings.</p

Strategically Equivalent Contests

Using a two-player Tullock-type contest, we show that intuitively and structurally different contests can be strategically equivalent. Strategically equivalent contests generate the same best response functions and, as a result, the same equilibrium efforts. However, strategically equivalent contests may yield different equilibrium payoffs. We propose a simple two-step procedure to identify strategically equivalent contests. Using this procedure, we identify contests that are strategically equivalent to the original Tullock contest, and provide new examples of strategically equivalent contests. Finally, we discuss possible contest design applications and avenues for future theoretical and empirical research

Professors on the Board: Do They Contribute to Society Outside the Classroom?

According to our data, 38.5 % of S&P 1500 firms have at least one professor on their boards. Given the lack of research examining the roles and effects of academic faculty as members of boards of directors (professor–directors) on corporate outcomes, this study investigates whether firms with professor–directors are more likely to exhibit higher corporate social responsibility (CSR) performance ratings. Results indicate that firms with professor–directors do exhibit higher CSR performance ratings than those without. However, the influence of professor–directors on firm CSR performance ratings depends on their academic background—the positive association between the presence of professor–directors and firm CSR performance ratings is significant only when their academic background is specialized (e.g., science, engineering, and medicine). Finally, this positive association weakens when professor–directors hold an administrative position at their universities

Suicide in the Northern Territory, 1981-2002

Objective: To examine trends in suicide in the Northern Territory between 1981 and 2002, and demographic and other characteristics of people completing suicide in the Top End region in 2000-2002. Design: Retrospective descriptive analysis of Australian Bureau of Statistics death registration data and data from the NT Coroner's Office. Setting and participants: All residents of the NT who completed suicide between 1981 and 2002. Main outcome measures: Changes in the age-adjusted and age- and sex-specific rates of suicide in Indigenous and non-Indigenous NT residents over time; prior diagnosis of mental illness and use of alcohol or other drugs by those completing suicide. Results: The age-adjusted suicide rate in the NT increased significantly between 1981 and 2002 (P 0.05), respectively. Indigenous males aged under 45 years and non-Indigenous males aged 65 years and over were most at risk. In the Top End, a history of diagnosed mental illness was present in 49% of suicide cases, and misuse of alcohol or other drugs around the time of death was associated with 72% of suicide cases. Conclusion: Our study highlights the rising rate of suicide in the NT and suggests that suicide prevention initiatives need to specifically target Indigenous and non-Indigenous males in the age groups most at risk

Posture as Index for Approach-Avoidance Behavior

Approach and avoidance are two behavioral responses that make people tend to approach positive and avoid negative situations. This study examines whether postural behavior is influenced by the affective state of pictures. While standing on the Wii™ Balance Board, participants viewed pleasant, neutral, and unpleasant pictures (passively viewing phase). Then they had to move their body to the left or the right (lateral movement phase) to make the next picture appear. We recorded movements in the anterior-posterior direction to examine approach and avoidant behavior. During passively viewing, people approached pleasant pictures. They avoided unpleasant ones while they made a lateral movement. These findings provide support for the idea that we tend to approach positive and avoid negative situations

Baseline hospital performance and the impact of medical emergency teams: Modelling vs. conventional subgroup analysis

<p>Abstract</p> <p>Background</p> <p>To compare two approaches to the statistical analysis of the relationship between the baseline incidence of adverse events and the effect of medical emergency teams (METs).</p> <p>Methods</p> <p>Using data from a cluster randomized controlled trial (the MERIT study), we analysed the relationship between the baseline incidence of adverse events and its change from baseline to the MET activation phase using quadratic modelling techniques. We compared the findings with those obtained with conventional subgroup analysis.</p> <p>Results</p> <p>Using linear and quadratic modelling techniques, we found that each unit increase in the baseline incidence of adverse events in MET hospitals was associated with a 0.59 unit subsequent reduction in adverse events (95%CI: 0.33 to 0.86) after MET implementation and activation. This applied to cardiac arrests (0.74; 95%CI: 0.52 to 0.95), unplanned ICU admissions (0.56; 95%CI: 0.26 to 0.85) and unexpected deaths (0.68; 95%CI: 0.45 to 0.90). Control hospitals showed a similar reduction only for cardiac arrests (0.95; 95%CI: 0.56 to 1.32). Comparison using conventional subgroup analysis, on the other hand, detected no significant difference between MET and control hospitals.</p> <p>Conclusions</p> <p>Our study showed that, in the MERIT study, when there was dependence of treatment effect on baseline performance, an approach based on regression modelling helped illustrate the nature and magnitude of such dependence while sub-group analysis did not. The ability to assess the nature and magnitude of such dependence may have policy implications. Regression technique may thus prove useful in analysing data when there is a conditional treatment effect.</p

Coupling and Elastic Loading Affect the Active Response by the Inner Ear Hair Cell Bundles

Active hair bundle motility has been proposed to underlie the amplification mechanism in the auditory endorgans of non-mammals and in the vestibular systems of all vertebrates, and to constitute a crucial component of cochlear amplification in mammals. We used semi-intact in vitro preparations of the bullfrog sacculus to study the effects of elastic mechanical loading on both natively coupled and freely oscillating hair bundles. For the latter, we attached glass fibers of different stiffness to the stereocilia and observed the induced changes in the spontaneous bundle movement. When driven with sinusoidal deflections, hair bundles displayed phase-locked response indicative of an Arnold Tongue, with the frequency selectivity highest at low amplitudes and decreasing under stronger stimulation. A striking broadening of the mode-locked response was seen with increasing stiffness of the load, until approximate impedance matching, where the phase-locked response remained flat over the physiological range of frequencies. When the otolithic membrane was left intact atop the preparation, the natural loading of the bundles likewise decreased their frequency selectivity with respect to that observed in freely oscillating bundles. To probe for signatures of the active process under natural loading and coupling conditions, we applied transient mechanical stimuli to the otolithic membrane. Following the pulses, the underlying bundles displayed active movement in the opposite direction, analogous to the twitches observed in individual cells. Tracking features in the otolithic membrane indicated that it moved in phase with the bundles. Hence, synchronous active motility evoked in the system of coupled hair bundles by external input is sufficient to displace large overlying structures

Appointing Women to Boards: Is There a Cultural Bias?

Companies that are serious about corporate governance and business ethics are turning their attention to gender diversity at the most senior levels of business (Institute of Business Ethics, Business Ethics Briefing 21:1, 2011). Board gender diversity has been the subject of several studies carried out by international organizations such as Catalyst (Increasing gender diversity on boards: Current index of formal approaches, 2012), the World Economic Forum (Hausmann et al., The global gender gap report, 2010), and the European Board Diversity Analysis (Is it getting easier to find women on European boards? 2010). They all lead to reports confirming the overall relatively low proportion of women on boards and the slow pace at which more women are being appointed. Furthermore, the proportion of women on corporate boards varies much across countries. Based on institutional theory, this study hypothesizes and tests whether this variation can be attributed to differences in cultural settings across countries. Our analysis of the representation of women on boards for 32 countries during 2010 reveals that two cultural characteristics are indeed associated with the observed differences. We use the cultural dimensions proposed by Hofstede (Culture’s consequences: International differences in work-related values, 1980) to measure this construct. Results show that countries which have the greatest tolerance for inequalities in the distribution of power and those that tend to value the role of men generally exhibit lower representations of women on boards

Women on boards and firm performance

This study investigates the financial performance of Dutch companies both with and without women on their boards. The analysis extends earlier methods used in research by Catalyst (The bottom line: corporate performance and women's representation on boards, 2007) and McKinsey (Women matter. Gender diversity, a corporate performance driver. McKinsey & Company, USA, 2007), two studies that are often cited in the literature, although, each has a number of methodological shortcomings. This article adds to the international debate, which is often normative, through examining 99 listed companies in the Dutch Female Board Index. Our results show that firms with women directors perform better than those without women on their boards