PHYSICAL ACTIVITY AND COGNITIVE FUNCTION OF LONG DISTANCE WALKERS: STUDYING FOUR DAYS MARCHES PARTICIPANTS.

OBJECTIVE: Studies show physical activity to be beneficial for cognitive function. However, studies usually included individuals who were not particularly inclined to exercise. Following research among master athletes, we examined associations between physical activity and cognitive function in participants of the International Nijmegen Four Days Marches. These individuals are also inclined to exercise. On 4 consecutive days > 40,000 participants walk a daily distance of 30-50 km (120-200 km or 75-125 miles in total). METHOD: Four Days Marches participants and less active or inactive control participants from the Nijmegen Exercise Study were examined. Self-reported current and lifelong physical activities were quantified in Metabolic Equivalent of Task minutes/day and training walking speed was estimated in km/h. Cognitive functioning in the domains of working memory, executive function, and visuospatial short-term memory was assessed using the validated Brain Aging Monitor. RESULTS: Data from 521 participants (mean age 54.7, standard deviation 12.9) showed neither positive associations between lifelong physical activity and working memory, executive function, and visuospatial short-term memory nor positive associations between current physical activity and cognitive functioning in these domains (P-values > 0.05). However, a positive association between training walking speed and working memory was revealed (age adjusted Beta = 0.18, P-value < 0.01). CONCLUSION: Walking speed, as a surrogate marker of fitness, but not lifelong and current physical activity levels were associated with cognitive function. Therefore, walking speed deserves more attention in research aimed at unravelling associations between physical activity and cognitive function

Spin-Dependent Macroscopic Forces from New Particle Exchange

Long-range forces between macroscopic objects are mediated by light particles that interact with the electrons or nucleons, and include spin-dependent static components as well as spin- and velocity-dependent components. We parametrize the long-range potential between two fermions assuming rotational invariance, and find 16 different components. Applying this result to electrically neutral objects, we show that the macroscopic potential depends on 72 measurable parameters. We then derive the potential induced by the exchange of a new gauge boson or spinless particle, and compare the limits set by measurements of macroscopic forces to the astrophysical limits on the couplings of these particles.Comment: 37 page

The weak strangeness production reaction pn→pΛpn \to p\Lambda in a one-boson-exchange model

The weak production of Lambdas in nucleon-nucleon scattering is studied in a meson-exchange framework. The weak transition operator for the $NN \to N \Lambda$ reaction is identical to a previously developed weak strangeness-changing transition potential $\Lambda N \to NN$ that describes the nonmesonic decay of hypernuclei. The initial $NN$ and final $YN$ state interaction has been included by using realistic baryon-baryon forces that describe the available elastic scattering data. The total and differential cross sections as well as the parity-violating asymmetry are studied for the reaction $pn \to p\Lambda$. These observables are found to be sensitive to the choice of the strong interaction potential and the structure of the weak transition potential.Comment: 25 pages, 8 postscript figures. Submitted to Phys. Rev.

Neutron star matter equation of state and gravitational wave emission

The EOS of strongly interacting matter at densities ten to fifteen orders of magnitude larger than the typical density of terrestrial macroscopic objects determines a number of neutron star properties, including the pattern of gravitational waves emitted following the excitation of nonradial oscillation modes. This paper reviews some of the approaches employed to model neutron star matter, as well as the prospects for obtaining new insights from the experimental study of gravitational waves emitted by neutron stars.Comment: 15 pages, 8 figures. To be published as a Brief Review in Modern Physics Letters

The nonmesonic weak decay of the hypertriton

The nonmesonic decay of the hypertriton is calculated based on a hypertriton wavefunction and 3N scattering states, which are rigorous solutions of 3-body Faddeev equations using realistic NN and hyperon-nucleon interactions. The pion-exchange together with heavier meson exchanges for the $\Lambda N \to N N$ transition is considered. The total nonmesonic decay rate is found to be 0.5% of the free $\Lambda$ decay rate. Integrated as well as differential decay rates are given. The p- and n- induced decays are discussed thoroughly and it is shown that the corresponding total rates cannot be measured individually.Comment: 27 pages, 20 figures, revtex, submitted to Phys. Rev.

Pion-Lambda-Sigma Coupling Extracted from Hyperonic Atoms

The latest measurements of the atomic level width in Sigma-hyperonic Pb atom offer the most accurate datum in the region of low-energy Sigma-hyperon physics. Atomic widths are due to the conversion of Sigma-nucleon into Lambda-nucleon. In high angular momentum states this conversion is dominated by the one-pion exchange. A joint analysis of the data of the scattering of negative-Sigma on proton converting into a Lambda and a neutron and of the atomic widths allows to extract a pseudovector pion-hyperon-Sigma coupling constant of 0.048 with a statistical error of +-0.005 and a systematic one of +-0.004. This corresponds to a pseudoscalar coupling constant of 13.3 with a statistical uncertainty of 1.4 and a systematic one of 1.1.Comment: 12 pages, 1 figure, Use of Revtex.st

Inclusive K+K^+ and exclusive K+YK^+Y photoproduction on the deuteron: Λ\Lambda- and Σ\Sigma-threshold phenomena

Inclusive $K^+$ and exclusive $K^+Y$ photoproduction on the deuteron are investigated theoretically. Modern hyperon-nucleon forces and a recently updated kaon photoproduction operator for the $\gamma +N\to K^++Y$ process are used. Sizable effects of the hyperon-nucleon final state interaction are found near the $K^+\Lambda N$ and $K^+\Sigma N$ thresholds in the inclusive reaction. Angular distributions for the exclusive process show clear $YN$ final state interaction effects in certain kinematic regions. Precise data especially for the inclusive process around the $K^+\Sigma N$ threshold would help to clarify the strength and property of the $\Lambda N-\Sigma N$ interaction.Comment: 14 pages, 10 figure

Surgical repair of post-infarction ventricular free-wall rupture in the Netherlands: data from a nationwide registry

Background: Ventricular free-wall rupture (VFWR) is an infrequent but catastrophic complication of acute myocardial infarction (AMI). Most reports about outcome after surgical treatment are single-center experiences. We examined the early and mid-term outcomes after surgical repair of post-AMI VFWR using the Netherlands Heart Registration (NHR) database. Methods: We included data from NHR patients (&gt;18 years old) who underwent surgery for post-AMI VFWR between 2014 and 2019. The primary end-point was in-hospital mortality. Secondary outcomes included postoperative complications and mid-term survival. Results: The study included 148 patients (54.7% male, mean age 66.5±11.1 years). Critical preoperative status was found in 62.6% of subjects. In-hospital mortality was 31.1% (46 of 148). Multivariable analysis identified female sex [odds ratio (OR), 5.49; 95% confidence interval (CI): 2.24–13.46] and critical preoperative status (OR, 4.06; 95% CI: 1.36–12.13) as independent predictors of in-hospital mortality. The overall median postoperative follow-up was 2.2 (interquartile range, 0.7–3.8) years. Overall survival rates at three and five years were 58.9% and 55.7%, respectively. Among hospital survivors, only 15 (14.7%) patients died during follow-up, with a five-year survival rate of 80.8%. Conclusions: In-hospital mortality after surgical repair of post-AMI VFWR is considerable. Female sex and preoperative critical status are independent predictors of early postoperative (in-hospital) death. Logistic EuroSCORE I can reliably predict in-hospital mortality (optimal cut-off &gt;33%). Mid-term follow-up of patients surviving in-hospital course shows excellent results