Constraints on Large Extra Dimensions with Bulk Neutrinos

We consider right-handed neutrinos propagating in $\delta$ (large) extra dimensions, whose only coupling to Standard Model fields is the Yukawa coupling to the left-handed neutrino and the Higgs boson. These theories are attractive as they can explain the smallness of the neutrino mass, as has already been shown. We show that if $\delta$ is bigger than two, there are strong constraints on the radius of the extra dimensions, resulting from the experimental limit on the probability of an active state to mix into the large number of sterile Kaluza-Klein states of the bulk neutrino. We also calculate the bounds on the radius resulting from requiring that perturbative unitarity be valid in the theory, in an imagined Higgs-Higgs scattering channel.Comment: 24 pages, 4 figures, revtex4. v2: Minor typos corrected, references adde

Pruritus and postoperative nausea and vomiting after intrathecal morphine in spinal anaesthesia for caesarean section: Prospective cohort study

Background: Spinal anaesthesia is a common anaesthetic technique for caesarean sections. Neuraxial opioids such as intrathecal morphine may cause common adverse effects (pruritus, post-operative nausea and vomiting). Objectives: We investigated the incidence, severity and need for treatment of pruritus and post-operative nausea and vomiting following administration of intrathecal morphine in spinal anaesthesia for caesarean section at KK Women’s and Children’s Hospital, Singapore. Methods: We conducted a prospective study involving 124 parturients who received intrathecal morphine in spinal anaesthesia for caesarean section from October 2012 to October 2014. Results: Seventy patients (56.5%) had moderate or severe pruritus (score 4–10), while 54 patients (43.5%) had no or mild pruritus (score 0–3). Mean (SD) value of the worst pruritus score reported on a scale of 0–10 was 4 (2.59). Only seven out of the 124 patients (5.6%) required treatment for pruritus. With respect to distress and bother from itching in the past 24 hours on a score of 0–4, the mean score reported was 1.7 (1.23). Fourteen (11.2%) patients reported vomiting, dry-retching and nausea. Six (4.8%) patients had nausea that interfered with activities of daily living. Four (3.2%) patients had clinically significant post-operative nausea and vomiting. Seven (5.6%) patients received anti-emetics. The average Overall Benefit of Analgesia Score was 3.8 (SD 2.6, min–max: 0–15). The average (SD) maternal satisfaction with pain relief and side effects was 84.9% (9.9%). Conclusion: There is a high incidence of pruritus, with most women reporting moderate to severe pruritus. The incidence of post-operative nausea and vomiting is low, and women reported good maternal satisfaction

Epidemiology and outcomes of hospital-acquired bloodstream infections in intensive care unit patients: the EUROBACT-2 international cohort study

Purpose In the critically ill, hospital-acquired bloodstream infections (HA-BSI) are associated with significant mortality. Granular data are required for optimizing management, and developing guidelines and clinical trials. Methods We carried out a prospective international cohort study of adult patients (≥ 18 years of age) with HA-BSI treated in intensive care units (ICUs) between June 2019 and February 2021. Results 2600 patients from 333 ICUs in 52 countries were included. 78% HA-BSI were ICU-acquired. Median Sequential Organ Failure Assessment (SOFA) score was 8 [IQR 5; 11] at HA-BSI diagnosis. Most frequent sources of infection included pneumonia (26.7%) and intravascular catheters (26.4%). Most frequent pathogens were Gram-negative bacteria (59.0%), predominantly Klebsiella spp. (27.9%), Acinetobacter spp. (20.3%), Escherichia coli (15.8%), and Pseudomonas spp. (14.3%). Carbapenem resistance was present in 37.8%, 84.6%, 7.4%, and 33.2%, respectively. Difficult-to-treat resistance (DTR) was present in 23.5% and pan-drug resistance in 1.5%. Antimicrobial therapy was deemed adequate within 24 h for 51.5%. Antimicrobial resistance was associated with longer delays to adequate antimicrobial therapy. Source control was needed in 52.5% but not achieved in 18.2%. Mortality was 37.1%, and only 16.1% had been discharged alive from hospital by day-28. Conclusions HA-BSI was frequently caused by Gram-negative, carbapenem-resistant and DTR pathogens. Antimicrobial resistance led to delays in adequate antimicrobial therapy. Mortality was high, and at day-28 only a minority of the patients were discharged alive from the hospital. Prevention of antimicrobial resistance and focusing on adequate antimicrobial therapy and source control are important to optimize patient management and outcomes