Cutting edges at random in large recursive trees

We comment on old and new results related to the destruction of a random recursive tree (RRT), in which its edges are cut one after the other in a uniform random order. In particular, we study the number of steps needed to isolate or disconnect certain distinguished vertices when the size of the tree tends to infinity. New probabilistic explanations are given in terms of the so-called cut-tree and the tree of component sizes, which both encode different aspects of the destruction process. Finally, we establish the connection to Bernoulli bond percolation on large RRT's and present recent results on the cluster sizes in the supercritical regime.Comment: 29 pages, 3 figure

A Systematic Literature Review of the Humanistic Burden of COPD

Background: Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide, causing substantial economic and social burden. Objective: This review assessed the patient-reported humanistic burden associated with moderate to very severe COPD, specifically the impact on health-related quality of life (HRQoL), symptoms, limitations in daily life, and emotional implications, through the use of HRQoL instruments. Methods: A systematic review was conducted to retrieve relevant clinical data from published literature using a representative sample of countries where healthcare systems provide wide availability of COPD medications and/or universal coverage includes respiratory medicines (Australia, Canada, China, France, Germany, Italy, Spain, the UK, and the USA). The primary inclusion criteria were patients with moderate to very severe COPD. HRQoL was quantified with non-disease-specific and disease-specific questionnaires. Results: In total, 82 studies from 95 publications presented HRQoL data from patients with moderate to very severe COPD. Patient-reported HRQoL declined with worsening airflow limitation, advancing GOLD group, and increasing exacerbation frequency. Both increasing frequency of hospitalization for COPD exacerbations and recurrent hospitalization adversely impacted HRQoL. Comorbidity incidence was higher in patients with increased airflow limitation. It was associated with a further decline in HRQoL and increased depression and anxiety, particularly as disease-associated pain worsened. Physical activity improved HRQoL over time. Conclusion: This review highlighted the impact of exacerbations and associated hospitalizations on the humanistic burden of COPD. These findings underline the importance of managing COPD actively, including prompt and appropriate use of pharmacological and non-pharmacological therapies that can improve symptoms and reduce the risk of exacerbations, thereby lessening the humanistic burden. Future reviews could consider a broader range of countries and publications to further assess the humanistic impact of COPD in low- and middle-income economies

Pure-radiation gravitational fields with a simple twist and a Killing vector

Pure-radiation solutions are found, exploiting the analogy with the Euler- Darboux equation for aligned colliding plane waves and the Euler-Tricomi equation in hydrodynamics of two-dimensional flow. They do not depend on one of the spacelike coordinates and comprise the Hauser solution as a special subcase.Comment: revtex, 9 page

Localization of thioredoxin in the rat brain and functional implications

The immunoreactivity for thioredoxin, which catalyzes protein disulfide reductions, has previously been shown to exist in nerve cells and their axons. Here we demonstrate the localization of thioredoxin mRNA as revealed by in situ hybridization in the rat brain. The gene is expressed in nerve cells of a variety of brain regions, for example, the cerebral cortex, the piriform cortex, the medial preoptic area, the CA3/CA4 region of the hippocampal formation, the dentate gyrus, the paraventricular nucleus of the hypothalamus, the arcuate nucleus, the substantia nigra pars compacta, the locus coeruleus, the ependyma of the 4th ventricle, and the epithelial cells of the choroid plexus. This distribution implicates an important function in nerve cell metabolism, especially in regions with high energy demands and indicates a role of the choroid plexus in nerve cell protection from environmental influences. It was found that after mechanical injury induced by partial unilateral hemitransection the thioredoxin mRNA expression is upregulated in the lesioned area and spreads to the cortical hemispheres at the lesioned level. This induction suggests a function of thioredoxin in the regeneration machinery of the brain following mechanical injury and oxidative stress

A taxonomic revision of Capnophyllum (Apiaceae: Apioideae)

AbstractThe Cape endemic genus Capnophyllum Gaertn. is revised. As a result of valuable recent collections and extensive fieldwork, this hitherto neglected genus was found to comprise four annual species, two of which are newly described, namely C. lutzeyeri Magee and B.-E.van Wyk, and C. macrocarpum Magee and B.-E.van Wyk. The four species are distinguished from one another by their fruit morphology (relative length of the styles, the shape and position of the stylopodium, fruit size, surface sculpturing, and the presence or absence of a sterile apical portion) and fruit anatomy (marginal wings slightly or prominently involute and secondary ribs present or absent). A comprehensive key to the species, their complete nomenclature and typification, together with complete descriptions and known geographical distributions for all the species are presented and illustrated