Myopic progression throughout the pre-presbyopic adult years

The documentation of the trends and progression of myopia has been a topic of many previous studies. This retrospective study was designed to track and analyze myopic progression in the pre-presbyopic adult years. Records of seventy-seven non-RGP/ PMMA subjects between 20-40 years of age were reviewed and then grouped by decade and gender for further data comparisons. Statistical analyses showed significant myopic progression, but there was no significant difference in levels of myopic progression between males and females or the 20-30 vs. the 30-40 year age ranges. Results show the need for further studies that will take into account additional data such as the subjects\u27 occupation, level of education, race, axial length, and keratometry readings

Advantages and pitfalls of different types of studies for investigations of the impact of food on health

Several types of studies can be used to elucidate various aspects of the effect of food on human health. The main categories are: • Epidemiological (observational) studies with humans. These can be prospective, where the diet is recorded and health indicators are moni-tored after the first recording, or retrospective, where people who have a disease are identified and it is then investigated if their diet has been different from those who did not get the same disease. • Intervention studies with animals or humans, where the outcome is differences in indicators of health between groups eating different controlled diets. • In vitro studies, where specific aspects of the mechanisms of the effects of food or food com-ponents are studied in cell cultures, isolated or-gans or on enzyme activities. Each type of study is useful for elucidation of certain types or aspects of hypotheses. They also differ in terms of sensitivity (precision) and accuracy (risk of confounding with other influences than the food it-self). A thorough understanding of the effect of a food on human health requires that all three types of stud-ies give corresponding and predictable results

Changes in lower limb muscle function and muscle mass following exercise-based interventions in patients with chronic obstructive pulmonary disease : a review of the English-language literature

Chronic obstructive pulmonary disease (COPD) patients often experience lower limb muscle dysfunction and wasting. Exercise-based training has potential to improve muscle function and mass, but literature on this topic is extensive and heterogeneous including numerous interventions and outcomemeasures. This reviewuses a detailed systematic approach to investigate the effect of this wide range of exercise-based interventions on muscle function and mass. PUBMED and PEDro databases were searched. In all, 70 studies (n = 2504 COPD patients) that implemented an exercise-based intervention and reported muscle strength, endurance, or mass in clinically stable COPD patients were critically appraised. Aerobic and/or resistance training, high-intensity interval training, electrical or magnetic muscle stimulation, whole-body vibration, andwater-based training were investigated. Muscle strength increased in 78%, muscle endurance in 92%, and muscle mass in 88% of the cases where that specific outcome was measured. Despite large heterogeneity in exercise-based interventions and outcome measures used, most exercise-based trials showed improvements in muscle strength, endurance, and mass in COPD patients. Which intervention(s) is (are) best for which subgroup of patients remains currently unknown. Furthermore, this literature review identifies gaps in the current knowledge and generates recommendations for future research to enhance our knowledge on exercise-based interventions in COPD patients

Biologische Qualität: Mögliche Auswirkungen biologisch erzeugter Lebensmittel auf die menschliche Gesundheit

The greatly increased market share of organic food, has prompted increasing interest in investigating whether there are actual differences in the effects of organic and conventional food on health. Previous studies have focussed on composition analyses and have therefore not been able to provide definitive proof for differences between these two food production systems in terms of long-term impact on human health. Also the designs of some of these studies were inadequate to provide proof for definite composition differences. There are virtually no human dietary intervention and cohort studies, which can provide definite proof for potential health impacts. When taking into account the present knowledge in nutrition, toxicology, physiology and ecological science, there are ample examples that the methods used for production of food do impact on food composition or other aspects of food quality, and that these differences are large enough to make a real difference for the consumer in terms of health. Fertilisation methods affect the composition of plant foods, and also the risks of contamination by mycotoxin-producing fungi. Feed and housing similarly affect the composition and microbiology of animal foods. Our understanding of what is good or bad for health advances continuously, and in several cases new data have overturned old dogmas, which were revealed to have been based on (wrong) assumptions rather than good science. For example, probably due to the generally lower availability of nitrogen to the plants, levels of certain secondary metabolites in organic fresh plant foods are consistently higher than in corresponding conventional products (typically 10-50% more). Based on epidemiological data, the increase in life expectancy by a doubling of the intake of (conventional) vegetables has been estimated to 1-2 years. So if the bioactive secondary metabolites are responsible for this effect, changing to organic vegetables without changing intake will increase the life span by 1-12 months. While the differences between production methods are likely to cause general differences in food quality between organic and conventional products, many of the methods that benefit food quality are not necessarily restricted to either organic or conventional systems. Understanding the links between production methods and food quality therefore allows improvement of the products of any system, whether organic or conventional

Theoretical Black Hole Mass Distributions

We derive the theoretical distribution function of black hole masses by studying the formation processes of black holes. We use the results of recent 2D simulations of core-collapse to obtain the relation between remnant and progenitor masses and fold it with an initial mass function for the progenitors. We examine how the calculated black-hole mass distributions are modified by (i) strong wind mass loss at different evolutionary stages of the progenitors, and (ii) the presence of close binary companions to the black-hole progenitors. Thus, we are able to derive the binary black hole mass distribution. The compact remnant distribution is dominated by neutron stars in the mass range 1.2-1.6Msun and falls off exponentially at higher remnant masses. Our results are most sensitive to mass loss from winds which is even more important in close binaries. Wind mass-loss causes the black hole distribution to become flatter and limits the maximum possible black-hole mass (<10-15Msun). We also study the effects of the uncertainties in the explosion and unbinding energies for different progenitors. The distributions are continuous and extend over a broad range. We find no evidence for a gap at low values (3-5Msun) or for a peak at higher values (~7Msun) of black hole masses, but we argue that our black hole mass distribution for binaries is consistent with the current sample of measured black-hole masses in X-ray transients. We discuss possible biases against the detection or formation of X-ray transients with low-mass black holes. We also comment on the possibility of black-hole kicks and their effect on binaries.Comment: 22 pages, submitted to Ap