602 research outputs found
Mechanical characterization of solution-derived nanoparticle silver ink thin films
Mechanical properties of sintered silver nanoparticles are investigated via substrate curvature and nanoindentation methods. Substrate curvature measurements reveal that permanent microstructural changes occur during initial heating while subsequent annealing results in nearly elastic behavior of the thinner films. Thicker films were found to crack upon thermal treatment. The coefficient of thermal expansion was determined from linear slopes of curvature curves to be 1.9±0.097 ppm/°C, with elastic modulus and hardness determined via nanoindentation. Accounting for substrate effects, nanoindentation hardness and modulus remained constant for different film thicknesses and did not appear to be a function of annealing conditions. Hardness of 0.91 GPa and modulus of 110 GPa are somewhat lower than expected for a continuous nanocrystalline silver film, most likely due to porosity
A new approach to an age-old problem: solving externalities by incenting workers directly
Understanding motivations in the workplace remains of utmost import as economies around the world rely on increases in labor productivity to foster sustainable economic growth. This study makes use of a unique opportunity to “look under the hood” of an organization that critically relies on worker effort and performance. By partnering with Virgin Atlantic Airways on a field experiment that includes over 40,000 unique flights covering an eight-month period, we explore how information and incentives affect captains’ performance. Making use of more than 110,000 captain-level observations, we find that our set of treatments—which include performance information, personal targets, and prosocial incentives—induces captains to improve efficiency in all three key flight areas: pre-flight, in-flight, and post-flight. We estimate that our treatments saved between 266,000-704,000 kg of fuel for the airline over the eight-month experimental period. These savings led to between 838,000-2.22 million kg of CO2 abated at a marginal abatement cost of negative 250 savings per ton abated) over the eight-month experimental period. Methodologically, our approach highlights the potential usefulness of moving beyond an experimental design that focuses on short-run substitution effects, and it also suggests a new way to combat firm-level externalities: target workers rather than the firm as a whole
The impact of management practices on employee productivity: a field experiment with airline captains
Increasing evidence indicates the importance of management in determining firms’ productivity. Yet causal evidence regarding the effectiveness of management practices is scarce, especially for skilled labor in the developed world. In a field experiment measuring commercial airline captains’ productivity, we test four distinct management practices: performance monitoring, performance feedback, target setting, and prosocial incentives. These practices—particularly monitoring and target setting—significantly increase captains’ productivity on the targeted fuel-saving dimensions, with positive spillovers on job satisfaction and CO 2 emissions. The study reveals an uncharted research opportunity to delve into the black box of firms to examine the determinants of productivity among skilled labor
Exercise bouts at three different intensities fail to potentiate concentric power
Postactivation potentiation (PAP) has been hypothesized previously to occur during voluntary, concentric actions. We tested the hypothesis that one of at least three different intensities of conditioning exercises would evoke potentiation of power during the concentric, bench press throw (BPT). Twelve men (age = 22.9 &#; 2.7 years, bench press 1 repetition maximum (1RM) = 1.20 ± 0.12 kg•kg-1 body weight) completed five isotonic conditioning presses at ~55, 70, and 86% 1RM, in counterbalanced order, and on separate days. Average and peak power of the BPT using a load of 55% 1RM along with surface electromyography (EMG) of the triceps brachii were collected prior to and 4-minutes following each conditioning bout. Both average and peak power and EMG values (mean ± SD), respectively, were evaluated using two-way analyses of variance with repeated measures. Significant main effect decreases (p \u3c 0.05) in average (-18.6 ± 4.9 W) and peak power (-37.4 ± 9.9 W) occurred across the three different intensities evaluated. No main effects or interactions were observed with the EMG data. Contrary to the previously reported hypothesis, we were unable to demonstrate that conditioning exercise, with three different intensities, can evoke potentiation of power using a load equating to that which is optimum for power production
Public-Private Partnerships in the Water Sector
Public-private partnerships (PPPs) have grown in popularity as a method to leverage private-sector actors in the production of government services. With the global challenge of water insecurity, PPPs are becoming more common for large-scale water infrastructure projects such as desalination. Desalination facilities are complex and expensive operations, which means that understanding the appropriate context for PPPs is increasingly important. To understand how different PPP arrangements are used in the water sector, a team of researchers at Texas A&M University examined the global desalination sector and select cities around the world using PPPs for desalination. This brief summarizes what they learned about how risks are shared between the private and public sector, how those risks vary globally, and current trends in water infrastructure finance
ESG and Green Bonds in Public Finance
The rise of environmental, social, and governance (ESG) risk factors and green bonds in public finance has produced growing pains regarding labeling and misconceptions about ESG investor motivations. Understanding the current situation’s nuance is crucial for avoiding the pitfalls of blanket regulation and accommodating market demand
Polycentric governance and the impact of special districts on fiscal common pools
Local government services are increasingly being provided in fragmented polycentric systems where the overlapping jurisdictions draw resources from the same fiscal base. Developing optimal policies for the efficient management of fiscal resources requires a consideration of the total underlying fiscal pool. In this study, we evaluate the impact that special purpose districts have on debt ratios at the county “common pool” level in the State of Georgia (U.S.) between 2005-2014. Empirical findings suggest that inclusion of all general government and special purpose debt for each county may at times result in a greater burden on fiscal common pool than existing rules permit. These results call into question the efficacy of fiscal policies in a polycentric governance system that neglect to account for debt levels for all actors within the confines of a single fiscal common pool unit. Results also show that total debt ratios are significantly affected by special districts that operate within boundaries of a single county. We find no evidence that independent special districts have a differential impact on fiscal common pools compared to their dependent counterparts
Labelling, Deviance and Media
Labelling theory is a perspective that emerged as a distinctive approach to criminology during the 1960s, and was a major seedbed of the radical and critical perspectives that became prominent in the 1970s. It represented the highpoint of an epistemological shift within the social sciences away from positivism – which had dominated criminological enquiry since the late-1800s – and toward an altogether more relativistic stance on the categories and concepts of crime and control. It inspired a huge amount of work throughout the 1960s and 1970s, and still resonates powerfully today. This short chapter maps out some of the ways in which labelling, deviance, media and justice interact at the levels of definition and process. It presents an overview and analysis of key mediatised labelling processes, such as the highly influential concept of moral panics. It discusses how the interconnections between labelling, crime and criminal justice are changing in a context of technological development, cultural change and media proliferation. The conclusion offers an assessment and evaluation of labelling theory’s long-term impact on criminology
The effect of ageing on human lymphocyte subsets: comparison of males and females
There is reported to be a decline in immune function and an alteration in the frequency of circulating lymphocytes with advancing age. There are also differences in ageing and lifespan between males and females. We performed this study to see if there were differences between males and females in the frequency of the different lymphocyte subsets with age.Using flow cytometry we have examined different populations of peripheral blood leukocytes purified from healthy subjects with age ranging from the third to the tenth decade. We used linear regression analysis to determine if there is a linear relationship between age and cell frequencies. For the whole group, we find that with age there is a significant decline in the percentage of naĂŻve T cells and CD8(+) T cells, and an increase in the percentage of effector memory cells, CD4(+)foxp3(+) T cells and NK cells. For all cells where there was an effect of ageing, the slope of the curve was greater for men than for women and this was statistically significant for CD8(+)alphabeta(+) T cells and CD3(+)CD45RA(-)CCR7(-) effector memory cells. There was also a difference for naĂŻve cells but this was not significant.The cause of the change in percentage of lymphocyte subsets with age, and the different effects on males and females is not fully understood but warrants further study
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