The evolution of trait correlations constrains phenotypic adaptation to high CO2 in a eukaryotic alga

Microbes form the base of food webs and drive biogeochemical cycling. Predicting the effects of microbial evolution on global elemental cycles remains a significant challenge due to the sheer number of interacting environmental and trait combinations. Here, we present an approach for integrating multivariate trait data into a predictive model of trait evolution. We investigated the outcome of thousands of possible adaptive walks parameterized using empirical evolution data from the alga Chlamydomonas exposed to high CO2. We found that the direction of historical bias (existing trait correlations) influenced both the rate of adaptation and the evolved phenotypes (trait combinations). Critically, we use fitness landscapes derived directly from empirical trait values to capture known evolutionary phenomena. This work demonstrates that ecological models need to represent both changes in traits and changes in the correlation between traits in order to accurately capture phytoplankton evolution and predict future shifts in elemental cycling

A framework for optimization of diffusion-weighted MRI protocols for large field-of-view abdominal-pelvic imaging in multicenter studies.

PURPOSE: To develop methods for optimization of diffusion-weighted MRI (DW-MRI) in the abdomen and pelvis on 1.5 T MR scanners from three manufacturers and assess repeatability of apparent diffusion coefficient (ADC) estimates in a temperature-controlled phantom and abdominal and pelvic organs in healthy volunteers. METHODS: Geometric distortion, ghosting, fat suppression, and repeatability and homogeneity of ADC estimates were assessed using phantoms and volunteers. Healthy volunteers (ten per scanner) were each scanned twice on the same scanner. One volunteer traveled to all three institutions in order to provide images for qualitative comparison. The common volunteer was excluded from quantitative analysis of the data from scanners 2 and 3 in order to ensure statistical independence, giving n = 10 on scanner 1 and n = 9 on scanners 2 and 3 for quantitative analysis. Repeatability and interscanner variation of ADC estimates in kidneys, liver, spleen, and uterus were assessed using within-patient coefficient of variation (wCV) and Kruskal-Wallis tests, respectively. RESULTS: The coefficient of variation of ADC estimates in the temperature-controlled phantom was 1%-4% for all scanners. Images of healthy volunteers from all scanners showed homogeneous fat suppression and no marked ghosting or geometric distortion. The wCV of ADC estimates was 2%-4% for kidneys, 3%-7% for liver, 6%-9% for spleen, and 7%-10% for uterus. ADC estimates in kidneys, spleen, and uterus showed no significant difference between scanners but a significant difference was observed in liver (p < 0.05). CONCLUSIONS: DW-MRI protocols can be optimized using simple phantom measurements to produce good quality images in the abdomen and pelvis at 1.5 T with repeatable quantitative measurements in a multicenter study

The Influence of Fat Suppression Technique on Diffusion-weighted (DW) MRI in Lung Cancer

Purpose: To qualitatively and quantitatively investigate the effect of common vendor-related sequence variations in fat suppression techniques on the diagnostic performance of free-breathing DW protocols for lung imaging.Methods: 8 patients with malignant lung lesions were scanned in free breathing using two diffusion-weighted (DW) protocols with different fat suppression techniques: DWA used short-tau inversion recovery (STIR), and DWB used Spectral Adiabatic Inversion Recovery (SPAIR). Both techniques were obtained at two time points, between 1 hour and 1 week apart. Image quality was assessed using a 5-point scoring system. The number of lesions visible within lung, mediastinum and at thoracic inlet on the DW (b=800 s/mm2) images was compared. Signal-to-noise ratios (SNR) were calculated for lesions and para-spinal muscle. Repeatability of ADC values of the lesions was estimated for both protocols together and separately.Results: There was a signal void at the thoracic inlet in all patients with DWB but not with DWA. DWA images were rated significantly better than DWB images overall quality domains. (Cohens κ = 1). Although 8 more upper mediastinal/thoracic inlet lymph nodes were detected with DWA than DWB, this did not reach statistical significance (p = 0.23). Tumour ADC values were not significantly different between protocols (p=0.93), their ADC reproducibility was satisfactory (CoV=7.7%) and repeatability of each protocol separately was comparable (CoVDWA=3.7% (95% CI 2.5 7.1%) and CoVDWB=4.6% (95% CI 3.18.8%)).Conclusion: In a free-breathing DW-MRI protocol for lung, STIR fat suppression produced images of better diagnostic quality than SPAIR, while maintaining comparable SNR and providing repeatable quantitative ADC acceptable for use in a multicentre trial setting

Multivariate trait analysis reveals diatom plasticity constrained to a reduced set of biological axes

AbstractTrait-based approaches to phytoplankton ecology have gained traction in recent decades as phenotypic traits are incorporated into ecological and biogeochemical models. Here, we use high-throughput phenotyping to explore both intra- and interspecific constraints on trait combinations that are expressed in the cosmopolitan marine diatom genus Thalassiosira. We demonstrate that within Thalassiosira, phenotypic diversity cannot be predicted from genotypic diversity, and moreover, plasticity can create highly divergent phenotypes that are incongruent with taxonomic grouping. Significantly, multivariate phenotypes can be represented in reduced dimensional space using principal component analysis with 77.7% of the variance captured by two orthogonal axes, here termed a ‘trait-scape’. Furthermore, this trait-scape can be recovered with a reduced set of traits. Plastic responses to the new environments expanded phenotypic trait values and the trait-scape, however, the overall pattern of response to the new environments was similar between strains and many trait correlations remained constant. These findings demonstrate that trait-scapes can be used to reveal common constraints on multi-trait plasticity in phytoplankton with divergent underlying phenotypes. Understanding how to integrate trait correlational constraints and trade-offs into theoretical frameworks like biogeochemical models will be critical to predict how microbial responses to environmental change will impact elemental cycling now and into the future.</jats:p

Safety and practicability of using mid-upper arm circumference as a discharge criterion in community based management of severe acute malnutrition in children aged 6 to 59 months programmes

BACKGROUND: The use of proportional weight gain as a discharge criterion for MUAC admissions to programs treating severe acute malnutrition (SAM) is no longer recommended by WHO. The critical limitation with the proportional weight gain criterion was that children who are most severely malnourished tended to receive shorter treatment compared to less severely malnourished children. Studies have shown that using a discharge criterion of MUAC ≥ 125 mm eliminates this problem but concerns remain over the duration of treatment required to reach this criterion and whether this discharge criterion is safe. This study assessed the safety and practicability of using MUAC ≥ 125 mm as a discharge criterion for community based management of SAM in children aged 6 to 59 months. METHODS: A standards-based trial was undertaken in health facilities for the outpatient treatment of SAM in Lilongwe District, Malawi. 258 children aged 6 to 51 months were enrolled with uncomplicated SAM as defined by a MUAC equal or less than 115 mm without serious medical complications. Children were discharged from treatment as 'cured' when they achieved a MUAC of 125 mm or greater for two consecutive visits. After discharge, children were followed-up at home every two weeks for three months. RESULTS: This study confirms that a MUAC discharge criterion of 125 mm or greater is a safe discharge criterion and is associated with low levels of relapse to SAM (1.9 %) and mortality (1.3 %) with long durations of treatment seen only in the most severe SAM cases. The proportion of children experiencing a negative outcome was 3.2 % and significantly below the 10 % standard (p = 0.0013) established for the study. All children with negative outcomes had achieved weight-for-height z-score (WHZ) above -1 z-scores at discharge. Children admitted with lower MUAC had higher proportional weight gains (p < 0.001) and longer lengths of stay (p < 0.0001). MUAC at admission and attendance were both independently associated with cure (p < 0.0001). There was no association with negative outcomes at three months post discharge for children with heights at admission below 65 cm than for taller children (p = 0.5798). CONCLUSIONS: These results are consistent with MUAC ≥ 125 mm for two consecutive visits being a safe and practicable discharge criterion. Use of a MUAC threshold of 125 mm for discharge achieves reasonable lengths of stay and was also found to be appropriate for children aged six months or older who are less than 65 cm in height at admission. Early detection and recruitment of SAM cases using MUAC in the community anBiomedCentral open acces

Reliability Assessment of New and Updated Consumer-Grade Activity and Heart Rate Monitors

The aim of this paper is to address the need for reliability assessments of new and updated consumer-grade activity and heart rate monitoring devices. This issue is central to the use of these sensor devices and it is particularly important in their medical and assisted living application. Using an example lightweight empirical approach, experimental results for heart rate acquisitions from Garmin VivoSmart 3 (v4.10) smartwatch monitors are presented and analyzed. The reliability issues of optically-acquired heart rates, especially during periods of activity, are demonstrated and discussed. In conclusion, the paper recommends the empirical assessment of new and updated activity monitors, the sharing of this data and the use of version information across the literature

Back to thiazide-diuretics for hypertension: reflections after a decade of irrational prescribing

BACKGROUND: Whether newer antihypertensive drugs, such as calcium channel blockers, angiotensin converting enzyme inhibitors and α blockers are more effective than thiazides and β blockers in preventing coronary disease, has been debated for years. DISCUSSION: Recently several trials addressing this issue have been finalised, and they provide a convincing answer: the newer drugs are no better than the older ones. In the largest trial to date (ALLHAT), thiazide-type diuretic was found to offer advantages over newer drugs. The medical community should now be capable of reaching consensus, and recommend thiazides as the first line therapy for the treatment of hypertension. Prescribing physicians, cardiologists, drug companies and health authorities are all partly responsible for the years of irrational prescribing that we have witnessed. SUMMARY: All stakeholders should now contribute in order to achieve what is clearly in the public's interest: implementing the use of thiazides in clinical practice