An upper limit to the photon fraction in cosmic rays above 10^19 eV from the Pierre Auger Observatory

An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies above 10^19 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample, support the conclusion that a photon origin of the observed events is not favoured

The Impact of Blockchain Adoption on Corporate Investment Efficiency

This study investigates the impact of blockchain technology adoption on corporate investment efficiency. Utilizing a difference-in-differences methodology on an international sample of Forbes Global 2000 companies between 2012 and 2021, we find that firms implementing blockchain exhibit significantly higher investment efficiency postadoption compared to non-adopters. This effect is more pronounced among ex ante informationally opaque firms. Our results suggest that blockchain adoption reduces overinvesting activities by restricting avenues for managerial discretion through enhanced transparency. Our findings contribute to the growing literature on blockchain’s real economic impacts and inform blockchain adoption decisions by demonstrating investment efficiency benefits

Do non-financial factors influence corporate dividend policies? Evidence from business strategy

In this paper, we examine the influence of business strategy on dividend policy. We find that firms following an innovation-oriented strategy (prospectors) pay significantly lower dividends than those following an efficiency-oriented strategy (defenders). Our cross-sectional analyses show that such association is more pronounced among firms with greater investment opportunities and superior performance. Further analysis reveals that prospectors make significantly more capital investment, consistent with prospectors paying fewer dividends to finance their investment activities. Moreover, we address potential endogeneity concerns by implementing (i) a triple-difference analysis (DiDiD) that exploits an exogenous shock that hinders innovation through curbing the supply of highly skilled employees and (ii) an instrumental variable approach. Our results are robust to a propensity-score-matched (PSM) analysis, the inclusion of individual business strategy components, and the use of alternative measures of the dependent variables. Overall, our findings highlight business strategy as an inherent and non-financial determinant of dividend policies

Exploring the antimicrobial potential of biogenically synthesized graphene oxide nanoparticles against targeted bacterial and fungal pathogens

Graphene oxide (GO) and reduced graphene oxide (rGO) nanoparticles were synthesized using 40 mL of lemon juice extract as a reducing agent. The synthesized nanoparticles were characterized using various analytical techniques, including UV–visible spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results confirmed the successful synthesis of GO and rGO nanoparticles with varied sizes and shapes. The synthesized nanoparticles were tested for their antimicrobial activity against a range of bacterial and fungal strains, including Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans, Fusarium oxysporum, and Aspergillus flavus. Multiple concentrations of GO and rGO nanoparticles were tested, and it was observed that 100 µg·mL−1 of both GO and rGO showed the highest inhibitory effect against bacterial and produced zones of inhibition of 17.66 mm, 18.67 mm, and 17.88 for E. coli, S. aureus, K. pneumoniae and 20.33, 22.45, and 21.34 mm for C. albicans, F. oxysporum, and A. flavus. Comparatively, GO performed well as compared to rGO regarding antimicrobial activity. The synthesized nanoparticles exhibited significant antimicrobial activity against various bacterial and fungal strains and have the potential to be developed as novel antimicrobial agents

Female directors, earnings management, and CEO incentive compensation: UK evidence

This study examines the effect of the exogenous increase in the presence of female directors on FTSE350 corporate boards in the UK, as mandated by the Davies Report (2011), on the association between earnings management and CEO incentive compensation. We use a hand-collected dataset of FTSE350 UK public companies between 2007 and 2015. The empirical design used is a difference-in-differences methodology where the treatment group is gender-diverse corporate boards and the control group is corporate boards that lack gender diversity. We use two measures of gender diversity that include executive and non-executive female directors. The results show a positive association between earnings management and CEO incentive compensation, and a negative association between female directors and earnings management. Moreover, the results suggest a negative effect for the presence of female directors on CEO incentive compensation. Finally, the main finding of the study is that female directors play a moderating role on the association between earnings management and CEO incentive compensation. Overall, we show some of the economic consequences that the increased presence of female directors on corporate boards carries to public firms