Cardiac output during exercise related to plasma atrial natriuretic peptide but not to central venous pressure in humans.

NEW FINDINGS: What is the central question of this study? Is cardiac output during exercise dependent on central venous pressure? What is the main finding and its importance? The increase in cardiac output during both rowing and running is related to preload to the heart as indicated by plasma atrial natriuretic peptide but unrelated to central venous pressure. The results indicate that in upright humans central venous pressure reflects the gravitational influence on central venous blood rather than preload to the heart. ABSTRACT: Aim This study evaluated the increase in cardiac output (CO) during exercise in relation to central venous pressure (CVP) and plasma arterial natriuretic peptide (ANP) as expressions of preload to the heart. Methods Seven healthy subjects (four men; 26 ± 3 years; 181± 8 cm height; and 76 ± 11 kg, weight; mean ± SD) rested in sitting and standing positions (in randomized order) and then rowed and ran at submaximal workloads. The CVP was recorded, CO (Modelflow) calculated, and arterial plasma ANP determined by radioimmunoassay. Results While sitting CO was 6.2 ± 1.6 l/min, plasma ANP 70 ± 10 pg/ml, and CVP 1.8 ± 1.1 mmHg (mean ± SD) and decreased to 5.9 ± 1.0 l/min, 63 ± 10 pg/ml, and -3.8 ± 1.2 mmHg, respectively when standing (P < 0.05). Ergometer rowing elicited an increase in CO to 22.5 ± 5.5 l/min as plasma ANP increased to 156 ± 11 pg/ml and CVP to 3.8 ± 0.9 mmHg (P < 0.05). Similarly, CO increased to 23.5 ± 6.0 l/min during running with albeit smaller (P < 0.05) increase in plasma ANP, but with little change in CVP (-0.9 ± 0.4 mmHg). Conclusion The increase in CO in response to exercise is related to preload to the heart as indicated by plasma ANP, but unrelated to CVP. The results indicate that in upright humans CVP reflects the gravitational influence on central venous blood rather than preload to the heart. This article is protected by copyright. All rights reserved

Thermodynamics of an Empty Box

A gas in a box is perhaps the most important model system studied in thermodynamics and statistical mechanics. Usually, studies focus on the gas, whereas the box merely serves as an idealized confinement. The present article focuses on the box as the central object and develops a thermodynamic theory by treating the geometric degrees of freedom of the box as the degrees of freedom of a thermodynamic system. Applying standard mathematical methods to the thermody- namics of an empty box allows equations with the same structure as those of cosmology and classical and quantum mechanics to be derived. The simple model system of an empty box is shown to have interesting connections to classical mechanics, special relativity, and quantum field theory

Temporal changes in the gut microbiota in farmed Atlantic cod (Gadus morhua) outweigh the response to diet supplementation with macroalgae

Background: Aquaculture successfully meets global food demands for many fish species. However, aquaculture production of Atlantic cod (Gadus morhua) is just 2.5% of total market production. For cod farming to be a viable economic venture specific challenges on how to increase growth, health and farming productivity need to be addressed. Feed ingredients play a key role here. Macroalgae (seaweeds) have been suggested as a functional feed supplement with both health and economic benefits for terrestrial farmed animals and fish. The impact of such dietary supplements to cod gut integrity and microbiota, which contribute to overall fish robustness is unknown. The objective of this study was to supplement the diet of juvenile Atlantic cod with macroalgae and determine the impacts on fish condition and growth, gut morphology and hindgut microbiota composition (16S rRNA amplicon sequencing). Fish were fed one of three diets: control (no macroalgal inclusion), 10% inclusion of either egg wrack (Ascophyllum nodosum) or sea lettuce (Ulva rigida) macroalgae in a 12-week trial. Results: The results demonstrated there was no significant difference in fish condition, gut morphology or hindgut microbiota between the U. rigida supplemented fish group and the control group at any time-point. This trend was not observed with the A. nodosum treatment. Fish within this group were further categorised as either ‘Normal’ or ‘Lower Growth’. ‘Lower Growth’ individuals found the diet unpalatable resulting in reduced weight and condition factor combined with an altered gut morphology and microbiome relative to the other treatments. Excluding this group, our results show that the hindgut microbiota was largely driven by temporal pressures with the microbial communities becoming more similar over time irrespective of dietary treatment. The core microbiome at the final time-point consisted of the orders Vibrionales (Vibrio and Photobacterium), Bacteroidales (Bacteroidetes and Macellibacteroides) and Clostridiales (Lachnoclostridium). Conclusions: Our study indicates that U. rigida macroalgae can be supplemented at 10% inclusion levels in the diet of juvenile farmed Atlantic cod without any impact on fish condition or hindgut microbial community structure. We also conclude that 10% dietary inclusion of A. nodosum is not a suitable feed supplement in a farmed cod diet

Early Detection, Diagnosis and Intervention Services for Young Children with Autism Spectrum Disorder in the European Union (ASDEU): Family and Professional Perspectives

Early services for ASD need to canvas the opinions of both parents and professionals. These opinions are seldom compared in the same research study. This study aims to ascertain the views of families and professionals on early detection, diagnosis and intervention services for young children with ASD. An online survey compiled and analysed data from 2032 respondents across 14 European countries (60.9% were parents; 39.1% professionals). Using an ordinal scale from 1 to 7, parents’ opinions were more negative (mean = 4.6; SD 2.2) compared to those of professionals (mean = 4.9; SD 1.5) when reporting satisfaction with services. The results suggest services should take into account child’s age, delays in accessing services, and active stakeholders’ participation when looking to improve services