Performance of a MOPA laser system for photocathode research

A Nd:YLF laser system with frequency doubled output is described. Several aspects concerning energy and stability of the pulses will be discussed. The system consists of a CW mode locked Nd:YLF oscillator and two double pass amplifiers having a total small signal gain of about a million which means care must be taken to prevent self-oscillations. Due to saturation effects the energy per micropulse is limited to 20 µJ, resulting in 8 µJ at the second harmonic frequency (526.5 nm). For the frequency conversion KTP type II is used. The short term timing stability was measured using a spectrum analyser and found to be less than 200 fs with a width of 450 Hz. The amplitude fluctuations over the 15 ¿s macropulse are determined by the saturation behaviour of the amplifiers and the shot to shot stability of the amplifiers. Third and fourth harmonic generation is under study

Bacillus cereus responses to acid stress

Coping with acid environments is one of the prerequisites for the soil saprophytic and human pathogenic lifestyle of Bacillus cereus. This minireview highlights novel insights in the responses displayed by vegetative cells and germinating spores of B. cereus upon exposure to low pH as well as organic acids, including acetic acid, lactic acid and sorbic acid. Insights regarding the possible acid-inflicted damage, physiological responses and protective mechanisms have been compiled based on single cell fluorescence microscopy, flow cytometry and transcriptome analyses

Primary and secondary oxidative stress in Bacillus

Coping with oxidative stress originating from oxidizing compounds or reactive oxygen species (ROS), associated with the exposure to agents that cause environmental stresses, is one of the prerequisites for an aerobic lifestyle of Bacillus spp. such as B. subtilis, B. cereus and B. anthracis. This minireview highlights novel insights in the primary oxidative stress response caused by oxidizing compounds including hydrogen peroxide and the secondary oxidative stress responses apparent upon exposure to a range of agents and conditions leading to environmental stresses such as antibiotics, heat and acid. Insights in the pathways and damaging radicals involved have been compiled based among others on transcriptome studies, network analyses and fluorescence techniques for detection of ROS at single cell level. Exploitation of the current knowledge for the control of spoilage and pathogenic bacteria is discussed

On the jitter of mode-locked pulses introduced by an optical fibre

Measurements on the jitter of mode-locked pulses of a Nd:YLF laser after travelling through an optical fibre are presented. For low powers self phase modulation occurs which leaves the jitter unaltered. For powers higher than the threshold of stimulated Raman scattering the jitter increases due to the exponential growth of the Stokes field

Parametric study of the behaviour of group velocity dispersion in optical pulse compression

An optical pulse compressor is investigated over a large range of compression factors, fiber lengths and laser powers. The given theory for zero group velocity dispersion is valid over the investigated range of grating-prism distances. The influence of stimulated Raman scattering limited the feasible compression factors due to instabilities of the output pulse. For long fiber lengths it is experimentally shown that group velocity dispersion is present while the theory of zero group velocity dispersion still predicts the right pulse duration. The advantage of the presence of group velocity dispersion is the improved beam quality. The optical pulse compressor investigated uses a mode-locked Nd:YLF laser followed by an adjustable fiber-grating compressor stage

‘Nudges’ may be effective at times, but policymakers can’t rely on them to tackle entrenched social problems.

Since the publication of 2008’s Nudge by Richard Thaler and Cass Sunstein, policy ‘nudges’ have been in fashion, with smaller interventions aimed at altering public behaviour in a subtle manner being adopted by many governments, including in the UK. Frank Mols looked at this phenomenon in a recent journal article, and argues here that while nudges undoubtedly can be effective, their limitations must be kept in mind

High intake of Ultra-Processed Foods and risk of Colorectal Cancer: The Norwegian Women and Cancer study

Background: Norway is one of the countries with the highest rate of colorectal cancer (CRC). Previous research on diet and CRC has been heavily based on nutrients and foods, but new findings indicate that the way we process food may be of importance. However, the findings are contradictory. Further, new findings indicate that CRC risk factors might affect colorectal subsites differently. As the modern diet is changing towards including more ultra-processed food (UPF), a better understanding of how food processing affects CRC might be a new approach to prevent CRC. This raises the question: is there an association between high intake of UPF and CRC risk? Method: 77,100 women (1625 cases) from the Norwegian Women and Cancer study were included in this prospective cohort analysis. Dietary intakes were collected using validated semi-quantitative food frequency questionnaires. The foods were categorized based on the degree they had been processed by using the NOVA classification system. Multivariable Cox proportional hazard models were used to assess the association between high intake of UPF and CRC risk. Results: A high UPF intake, compared to a low UPF intake, was not significantly significant associated with increased total CRC risk after adjusting for all covariates, including energy intake(HR=1.21; 95% CI 1.01-1.46, P-trend = 0.08). However, a high UPF intake, compared to a low UPF intake, was statistically significant associated with right-sided colon cancer when adjusting for covariates(HR=1.28; 95% CI 1.03-1.60, P-trend = 0.04). The average follow-up time was 17.4 years. Conclusions: Results in this large prospective cohort suggest no overall association between a high UPF intake and risk of CRC. However, an association between a high UPF intake and right-sided colon cancer was found. These findings indicate that UPF affects colorectal subsites differently. Further research investigating the association between UPF and CRC is needed to determine causality

Introduction

The Emory Bankruptcy Developments Journal hosted its Tenth Annual Symposium on February 28, 2013. Each year, EBDJ\u27s Symposium addresses current issues in bankruptcy law in a format that provides practicable information to today\u27s bankruptcy practitioners. With the help and support of the Atlanta Bankruptcy Bar, EBDJ\u27s Advisory Board, and our sponsoring firms, the Tenth Annual Emory Bankruptcy Developments Journal Symposium was a tremendous success. This year\u27s Symposium featured two panels: 1) a Corporate Panel Discussion focused on municipal restructuring; and 2) a Consumer Panel Discussion focused on exceptions to bankruptcy, especially defalcation in the upcoming Supreme Court case of Bullock v. BankChampaign. The following represents an edited transcript of the panels. Again, EBDJ would like to thank the efforts of its Advisory Board members, the panelists, and moderators for their exceptional efforts on our behalf. Finally, I would like to thank Steve Ferketic, David Mayer, Sophia Priola, Alex Clamon, and the EBDJ staff for their personal efforts toward the success of this year\u27s symposium