Covariant density functional theory: The role of the pion

We investigate the role of the pion in Covariant Density Functional Theory. Starting from conventional Relativistic Mean Field (RMF) theory with a non-linear coupling of the $\sigma$-meson and without exchange terms we add pions with a pseudo-vector coupling to the nucleons in relativistic Hartree-Fock approximation. In order to take into account the change of the pion field in the nuclear medium the effective coupling constant of the pion is treated as a free parameter. It is found that the inclusion of the pion to this sort of density functionals does not destroy the overall description of the bulk properties by RMF. On the other hand, the non-central contribution of the pion (tensor coupling) does have effects on single particle energies and on binding energies of certain nuclei.Comment: 12 pages, 5 figure

IC 4200: a gas-rich early-type galaxy formed via a major merger

We present the result of radio and optical observations of the S0 galaxy IC 4200. We find that the galaxy hosts 8.5 billion solar masses of HI rotating on a ~90 deg warped disk extended out to 60 kpc from the centre of the galaxy. Optical spectroscopy reveals a simple-stellar-population-equivalent age of 1.5 Gyr in the centre of the galaxy and V- and R-band images show stellar shells. Ionised gas is observed within the stellar body and is kinematically decoupled from the stars and characterised by LINER-like line ratios.We interpret these observational results as evidence for a major merger origin of IC 4200, and date the merger back to 1-3 Gyr ago.Comment: Accepted for publication in Astronomy & Astrophysics; 18 pages, 13 figures; the tables of Appendix C can be downloaded at http://www.astro.rug.nl/~pserra/IC420

The microbiota of the bilio-pancreatic system: A cohort, STROBE-compliant study

Background: The gut microbiota play an essential role in protecting the host against pathogenic microorganisms by modulating immunity and regulating metabolic processes. In response to environmental factors, microbes can hugely alter their metabolism. These factors can substantially impact the host and have potential pathologic implications. Particularly pathogenic microorganisms colonizing pancreas and biliary tract tissues may be involved in chronic inflammation and cancer evolution. Purpose: To evaluate the effect of bile microbiota on survival in patients with pancreas and biliary tract disease (PBD). Patients and Methods: We investigated 152 Italian patients with cholelithiasis (CHL), cholangitis (CHA), cholangiocarcinoma (CCA), gallbladder carcinoma (GBC), pancreas head carcinoma (PHC), ampullary carcinoma (ACA), and chronic pancreatitis (CHP). Demographics, bile cultures, therapy, and survival rates were analyzed in cohorts (T1 death <6 months; T2 death <12 months; T3 death <18 months, T3S alive at 18 months). Results: The most common bacteria in T1 were E. coli, K. pneumoniae, andP. aeruginosa. In T2, the most common bacteria were E. coli and P. aeruginosa. InT3, there were no significant bacteria isolated, while in T3S the most common bacteria were like those found in T1. E. coli and K. pneumoniae were positive predictors of survival for PHC and ACA, respectively. E. coli, K. pneumoniae, andP. aeruginosa showed a high percentage of resistant bacteria to 3CGS, aminoglycosides class, and quinolone group especially at T1 and T2 in cancer patients. Conclusions: An unprecedented increase of E. coli in bile leads to a decrease in survival. We suggest that some strains isolated in bile samples may be considered within the group of risk factors in carcinogenesis and/or progression of hepato-biliary malignancy. A better understanding of bile microbiota in patients with PBD should lead to a multifaceted approach to rapidly detect and treat pathogens before patients enter the surgical setting in tandem with the implementation of the infection control policy

A very extended reionization epoch ?

The recent observations of cross temperature-polarization power spectra of the Cosmic Microwave Background (CMB) made by the WMAP satellite are in better agreement with a high value of the Thomson scattering optical depth \tau \approx 0.17. This value is close to \tau = 0.3, which is taken as the upper limit in the parameter extraction analysis made by the WMAP team. However, models with \tau \sim 0.3 provide a good fit to current CMB data and are not significantly excluded when combined with Large Scale Structure data. By making use of a self-consistent reionization model, we verify the astrophysical feasibility of models with \tau \sim 0.3. It turns out that current data on various observations related to the thermal and ionization history of the intergalactic medium are not able to rule out \tau \sim 0.3. The possibility of a very extended reionization epoch can significantly undermine the WMAP constraints on crucial cosmological parameters such as the Hubble constant, the spectral index of primordial fluctuations and the amplitude of dark matter clustering.Comment: Accepted for publication in MNRAS. Revised to match the accepted versio

Modification of the 6-Hydroxydopamine Technique for the Correct Determination of Superoxide Dismutase

Heikkila & Cabbat (Anal. Biochem. 75, 356-362 (1976)) have proposed the autoxidation of the 6-hydroxydopamine as a method to test Superoxide dismutase activity in biological samples. This method has several advantages but in some instances leads to incorrect determinations. We present here a necessary modification of the method to avoid bias.Peer Reviewe

Mathematical models in nursing research

This paper discusses the use of advanced mathematical tools in nursing research, such as mathematical models used in medicine for description and prediction of experimental tumor growth. They are rarely used in nursing research, but fortunately in the last decade, their use is increased, mainly due to artificial intelligence and Big Data, with great benefits for further nursing development. Therefore, a strong interaction between nurses and mathemati-cians is needed to improve nursing research, and consequently, the nurses’ performance in daily work

Efecto de la congelación en rodillas animales. Estudio biomecánico experimental

Se estudia el comportamiento mecánico de rodillas animales que han sido congeladas en 1 o varias ocasiones mediante la aplicación de cargas axiales hasta la fractura o test destructivos. Se analizan el tipo y localización de fracturas aparecidas mediante un estudio radiográfico.We study the mechanical behavior in animal knees who are fresh frozen in one or various times. Axial loading are applied until the final fracture ( destructive test). Also it evaluates the tipe and localization of the fractures with radiological study

Irreversibility and the arrow of time in a quenched quantum system

Irreversibility is one of the most intriguing concepts in physics. While microscopic physical laws are perfectly reversible, macroscopic average behavior has a preferred direction of time. According to the second law of thermodynamics, this arrow of time is associated with a positive mean entropy production. Using a nuclear magnetic resonance setup, we measure the nonequilibrium entropy produced in an isolated spin-1/2 system following fast quenches of an external magnetic field and experimentally demonstrate that it is equal to the entropic distance, expressed by the Kullback-Leibler divergence, between a microscopic process and its time-reverse. Our result addresses the concept of irreversibility from a microscopic quantum standpoint.Comment: 8 pages, 7 figures, RevTeX4-1; Accepted for publication Phys. Rev. Let