Contribution from close and distant collisions to K-shell excitation in Ge measured using the channeling technique for relativistic protons, π+\pi^{+}, and π−\pi^{-}

For the first time, the impact-parameter dependence for K-shell ionization was measured for relativistic projectiles, although in an indirect way. Experimentally, channeling of GeV projectiles was used to gradually exclude close-encounter processes. In the present experiment, the Lorentz gamma factor varied between approximately 2 and approximately 100; in this region, the contribution from distant collisions becomes increasingly important and amounts to about 50% of the total yield for gamma approximately 100. The experimental data are compared to theoretical calculations of impact-parameter distributions, and the agreement is fair for both positive and negative particles

Measurement of average electron densities in Si and Ge using MeV delta -rays produced by channelled high-energy projectiles

For the first time, average electron densities in silicon and germanium were measured using the channeling effect for 5 and 12 GeV/c protons,\pi^{+} and\pi^{-}. In the investigation, the yield of MeV electrons emitted through the back of the target was measured. Such delta -ray yields are proportional to the local electron density averaged along the path of the projectile in the target. For well- aligned, positive particles, the electron yield is reduced to around 15% of normal yield for germanium and 25% for silicon, whereas negatively charged, channeled projectiles give an increase in yield by a factor of three compared to normal yield. The experimental results have been compared to yield curves calculated using the Lindhard channeling model in connection with special potential models, and very good agreement is obtained for positive particles when the electron density in the middle of channels is obtained by summing the contributions from many neighbouring strings. For positive projectiles, this channeling method is most sensitive far away from the strings, where other techniques are weak. The results for negative, channeled particles agree fairly well with simplified theoretical calculations, neglecting, channeled particles agree fairly well with simplified theoretical calculations, neglecting dechanneling and the lack of equilibrium in angular momenta in the transverse plane

An international assessment of the adoption of enhanced recovery after surgery (ERAS®) principles across colorectal units in 2019–2020

Aim: The Enhanced Recovery After Surgery (ERAS®) Society guidelines aim to standardize perioperative care in colorectal surgery via 25 principles. We aimed to assess the variation in uptake of these principles across an international network of colorectal units. Method: An online survey was circulated amongst European Society of Coloproctology members in 2019–2020. For each ERAS principle, respondents were asked to score how frequently the principle was implemented in their hospital, from 1 (‘rarely’) to 4 (‘always’). Respondents were also asked to recall whether practice had changed since 2017. Subgroup analyses based on hospital characteristics were conducted. Results: Of hospitals approached, 58% responded to the survey (195/335), with 296 individual responses (multiple responses were received from some hospitals). The majority were European (163/195, 83.6%). Overall, respondents indicated they ‘most often’ or ‘always’ adhered to most individual ERAS principles (18/25, 72%). Variability in the uptake of principles was reported, with universal uptake of some principles (e.g., prophylactic antibiotics; early mobilization) and inconsistency from ‘rarely’ to ‘always’ in others (e.g., no nasogastric intubation; no preoperative fasting and carbohydrate drinks). In alignment with 2018 ERAS guideline updates, adherence to principles for prehabilitation, managing anaemia and postoperative nutrition appears to have increased since 2017. Conclusions: Uptake of ERAS principles varied across hospitals, and not all 25 principles were equally adhered to. Whilst some principles exhibited a high level of acceptance, others had a wide variability in uptake indicative of controversy or barriers to uptake. Further research into specific principles is required to improve ERAS implementation