Ag alloyed Pd single-atom catalysts for efficient selective hydrogenation of acetylene to ethylene in excess ethylene

Semihydrogenation of acetylene in an ethylene-rich stream is an industrially important process. Conventional supported monometallic Pd catalysts offer high acetylene conversion, but they suffer from very low selectivity to ethylene due to overhydrogenation and the formation of carbonaceous deposits. Herein, a series of Ag alloyed Pd single-atom catalysts, possessing only ppm levels of Pd, supported on silica gel were prepared by a simple incipient wetness coimpregnation method and applied to the selective hydrogenation of acetylene in an ethylene-rich stream under conditions close to the front-end employed by industry. High acetylene conversion and simultaneous selectivity to ethylene was attained over a wide temperature window, surpassing an analogous Au alloyed Pd single-atom system we previously reported. Restructuring of AgPd nanoparticles and electron transfer from Ag to Pd were evidenced by in situ FTIR and in situ XPS as a function of increasing reduction temperature. Microcalorimetry and XANES measurements support both geometric and electronic synergetic effects between the alloyed Pd and Ag. Kinetic studies provide valuable insight into the nature of the active sites within these AgPd/SiO2 catalysts, and hence, they provide evidence for the key factors underpinning the excellent performance of these bimetallic catalysts toward the selective hydrogenation of acetylene under ethylene-rich conditions while minimizing precious metal usage.

Returns on key accounts:do the results justify the expenditures?

Purpose – The use of key accounts has become a mature trend and most industrial firms use this concept in some form. Selling firms establish key account teams to attend to important customers and consolidate their selling activities. Yet, despite such increased efforts on behalf of key accounts, sufficient research has not quantified the returns on key account strategy nor has it firmly established performance differences between key and non-key accounts within a firm. In response to this shortcoming, this study aims to examine returns on key accounts. Design Methodology/approach – Data were collected from a global consulting firm. The data collection started two years after the implementation of the key account program. Data were collected on recently acquired customers (within the previous year) at two time periods: year 1 and year 3 (based on company access of data). Findings – Initially, key accounts perform as well or better than other types of accounts. However, in the long term, key accounts are less satisfied, less profitable and less beneficial for a firm’s growth than other types of accounts. Because the returns to key account expenditures, thus, appear mixed, firms should be cautious in expanding their key account strategies. Research limitations implications – The study contributes to research in three areas. First, most research on the effectiveness of key accounts refers to the between-firm level, whereas this study examines the effect within a single firm. Second, this study examines the temporal aspects of key accounts, namely, what happens to key accounts over time, in comparison with other accounts in a fairly large sample. Third, it considers the survival rates of key accounts versus other types of accounts. Practical implications – The authors suggest that firms also need to track their key accounts better because the results show that key accounts are less satisfied, less profitable and less beneficial for a firm’s growth than other types of accounts. Originality/value – Extant research has not examined these issues.

Examining factors associated with excess mortality in older people (age ≥ 70 years) with diabetes - a 10-year cohort study of older people with and without diabetes

Aims: To compare all-cause mortality in older people with or without diabetes and consider the associated risk of comorbidity and polypharmacy. Methods: A 10-year cohort study using data from the Health Innovation Network database (2003-2013) comparing mortality in people aged ≥ 70 years with diabetes (DM cohort) (n = 35 717) and without diabetes (No DM cohort) (n = 307 918). Results: The mean age of the DM cohort was 78.1 ± 5.8 years vs. 79.0 ± 6.3 years in the No DM cohort. Mean diabetes duration was 8.2 ± 8.1 years, and 30% had diabetes for > 10 years. The DM cohort had a greater comorbidity load and people in this cohort were prescribed more therapies than the No DM cohort. The 5- and 10-year survival rates were lower in the DM cohort at 64% and 39%, respectively, compared with 72% and 50% in the No DM cohort. The excess mortality in the DM cohort was greatest in those aged <75 years with longer duration diabetes, the relative hazard for mortality was higher in females. Although comorbidity and polypharmacy were associated with increased mortality risk in the DM cohort, this risk was lower compared with the No DM cohort. The hazard ratios (95% confidence interval) for comorbidities > 4 and medicines ≥ 7 were 1.29 (1.19 to 1.41) and 1.34 (1.25 to 1.43) in the DM cohort and 1.63 (1.57 to 1.70) and 1.48 (1.40 to 1.56) in the No DM cohort, respectively. Conclusions: There is significant excess mortality in older people with diabetes, which is unexplained by comorbidity or polypharmacy. This excess is greatest in the younger old with longer disease duration, suggesting that it may be related to the effect of diabetes exposure.

Reviewing the hedge funds literature II:hedge funds' returns and risk management characteristics

This paper summarizes the literature on hedge funds (HFs) developed over the last two decades, particularly that which relates to risk management characteristics (a companion piece investigates the managerial characteristics of HFs). It discusses the successes and the shortfalls to date in developing more sophisticated risk management frameworks and tools to measure and monitor HF risks, and the empirical evidence on the role of the HFs and their investment behaviour and risk management practices on the stability of the financial system. It also classifies the HF literature considering the most recent contributions and, particularly, the regulatory developments after the 2007 financial crisis.

Recent advances in explaining hedge fund returns:implicit factors and exposures

We survey articles covering how hedge fund returns are explained, using largely non-linear multifactor models that examine the non-linear pay-offs and exposures of hedge funds. We provide an integrated view of the implicit factor and statistical factor models that are largely able to explain the hedge fund return-generating process. We present their evolution through time by discussing pioneering studies that made a significant contribution to knowledge, and also recent innovative studies that examine hedge fund exposures using advanced econometric methods. This is the first review that analyzes very recent studies that explain a large part of hedge fund variation. We conclude by presenting some gaps for future research.