The Effect of Scale on the Applicability of Taylor’s Frozen Turbulence Hypothesis in the Atmospheric Boundary Layer

Taylor’s frozen turbulence hypothesis is the central assumption invoked in most experiments designed to investigate turbulence physics with time resolving sensors. It is also frequently used in theoretical discussions when linking Lagrangian to Eulerian flow formalisms. In this work we seek to quantify the effectiveness of Taylor’s hypothesis on the field scale using water vapour as a passive tracer. A horizontally orientated Raman lidar is used to capture the humidity field in space and time above an agricultural region in Switzerland. High resolution wind speed and direction measurements are conducted simultaneously allowing for a direct test of Taylor’s hypothesis at the field scale. Through a wavelet decomposition of the lidar humidity measurements we show that the scale of turbulent motions has a strong influence on the applicability of Taylor’s hypothesis. This dependency on scale is explained through the use of dimensional analysis.We identify a ‘persistency scale’ that can be used to quantify the effectiveness of Taylor’s hypothesis, and present the accuracy of the hypothesis as a function of this non-dimensional length scale. These results are further investigated and verified through the use of large-eddy simulations.Keywords: Humidity, Atmospheric boundary layer, Taylor’s frozen turbulence hypothesis, Raman lida

Bacterial tolerance to host-exuded specialized metabolites structures the maize root microbiome.

Plants exude specialized metabolites from their roots, and these compounds are known to structure the root microbiome. However, the underlying mechanisms are poorly understood. We established a representative collection of maize root bacteria and tested their tolerance against benzoxazinoids (BXs), the dominant specialized and bioactive metabolites in the root exudates of maize plants. In vitro experiments revealed that BXs inhibited bacterial growth in a strain- and compound-dependent manner. Tolerance against these selective antimicrobial compounds depended on bacterial cell wall structure. Further, we found that native root bacteria isolated from maize tolerated the BXs better compared to nonhost Arabidopsis bacteria. This finding suggests the adaptation of the root bacteria to the specialized metabolites of their host plant. Bacterial tolerance to 6-methoxy-benzoxazolin-2-one (MBOA), the most abundant and selective antimicrobial metabolite in the maize rhizosphere, correlated significantly with the abundance of these bacteria on BX-exuding maize roots. Thus, strain-dependent tolerance to BXs largely explained the abundance pattern of bacteria on maize roots. Abundant bacteria generally tolerated MBOA, while low abundant root microbiome members were sensitive to this compound. Our findings reveal that tolerance to plant specialized metabolites is an important competence determinant for root colonization. We propose that bacterial tolerance to root-derived antimicrobial compounds is an underlying mechanism determining the structure of host-specific microbial communities

Evaluation of chronic lymphocytic leukemia by oligonucleotide-based microarray analysis uncovers novel aberrations not detected by FISH or cytogenetic analysis

<p>Abstract</p> <p>Background</p> <p>Cytogenetic evaluation is a key component of the diagnosis and prognosis of chronic lymphocytic leukemia (CLL). We performed oligonucleotide-based comparative genomic hybridization microarray analysis on 34 samples with CLL and known abnormal karyotypes previously determined by cytogenetics and/or fluorescence <it>in situ </it>hybridization (FISH).</p> <p>Results</p> <p>Using a custom designed microarray that targets >1800 genes involved in hematologic disease and other malignancies, we identified additional cryptic aberrations and novel findings in 59% of cases. These included gains and losses of genes associated with cell cycle regulation, apoptosis and susceptibility loci on 3p21.31, 5q35.2q35.3, 10q23.31q23.33, 11q22.3, and 22q11.23.</p> <p>Conclusions</p> <p>Our results show that microarray analysis will detect known aberrations, including microscopic and cryptic alterations. In addition, novel genomic changes will be uncovered that may become important prognostic predictors or treatment targets for CLL in the future.</p

Exposure to negative socio-emotional events induces sustained alteration of resting-state brain networks in older adults

Basic emotional functions seem well preserved in older adults. However, their reactivity to and recovery from socially negative events remain poorly characterized. To address this, we designed a ‘task–rest’ paradigm in which 182 participants from two independent experiments underwent functional magnetic resonance imaging while exposed to socio-emotional videos. Experiment 1 (N = 55) validated the task in young and older participants and unveiled age-dependent effects on brain activity and connectivity that predominated in resting periods after (rather than during) negative social scenes. Crucially, emotional elicitation potentiated subsequent resting-state connectivity between default mode network and amygdala exclusively in older adults. Experiment 2 replicated these results in a large older adult cohort (N = 127) and additionally showed that emotion-driven changes in posterior default mode network–amygdala connectivity were associated with anxiety, rumination and negative thoughts. These findings uncover the neural dynamics of empathy-related functions in older adults and help understand its relationship to poor social stress recovery

Delphi Initiative for Early-Onset Colorectal Cancer (DIRECt) International Management Guidelines

Background & aims: Patients with early-onset colorectal cancer (eoCRC) are managed according to guidelines that are not age-specific. A multidisciplinary international group (DIRECt), composed of 69 experts, was convened to develop the first evidence-based consensus recommendations for eoCRC. Methods: After reviewing the published literature, a Delphi methodology was used to draft and respond to clinically relevant questions. Each statement underwent 3 rounds of voting and reached a consensus level of agreement of ≥80%. Results: The DIRECt group produced 31 statements in 7 areas of interest: diagnosis, risk factors, genetics, pathology-oncology, endoscopy, therapy, and supportive care. There was strong consensus that all individuals younger than 50 should undergo CRC risk stratification and prompt symptom assessment. All newly diagnosed eoCRC patients should receive germline genetic testing, ideally before surgery. On the basis of current evidence, endoscopic, surgical, and oncologic treatment of eoCRC should not differ from later-onset CRC, except for individuals with pathogenic or likely pathogenic germline variants. The evidence on chemotherapy is not sufficient to recommend changes to established therapeutic protocols. Fertility preservation and sexual health are important to address in eoCRC survivors. The DIRECt group highlighted areas with knowledge gaps that should be prioritized in future research efforts, including age at first screening for the general population, use of fecal immunochemical tests, chemotherapy, endoscopic therapy, and post-treatment surveillance for eoCRC patients. Conclusions: The DIRECt group produced the first consensus recommendations on eoCRC. All statements should be considered together with the accompanying comments and literature reviews. We highlighted areas where research should be prioritized. These guidelines represent a useful tool for clinicians caring for patients with eoCRC

Delphi Initiative for Early-Onset Colorectal Cancer (DIRECt) International Management Guidelines

BACKGROUND & AIMS: Patients with early-onset colorectal cancer (eoCRC) are managed according to guidelines that are not age-specific. A multidisciplinary international group (DIRECt), composed of 69 experts, was convened to develop the first evidence-based consensus recommendations for eoCRC. METHODS: After reviewing the published literature, a Delphi methodology was used to draft and respond to clinically relevant questions. Each statement underwent 3 rounds of voting and reached a consensus level of agreement of ≥80%. RESULTS: The DIRECt group produced 31 statements in 7 areas of interest: diagnosis, risk factors, genetics, pathology-oncology, endoscopy, therapy, and supportive care. There was strong consensus that all individuals younger than 50 should undergo CRC risk stratification and prompt symptom assessment. All newly diagnosed eoCRC patients should receive germline genetic testing, ideally before surgery. On the basis of current evidence, endoscopic, surgical, and oncologic treatment of eoCRC should not differ from later-onset CRC, except for individuals with pathogenic or likely pathogenic germline variants. The evidence on chemotherapy is not sufficient to recommend changes to established therapeutic protocols. Fertility preservation and sexual health are important to address in eoCRC survivors. The DIRECt group highlighted areas with knowledge gaps that should be prioritized in future research efforts, including age at first screening for the general population, use of fecal immunochemical tests, chemotherapy, endoscopic therapy, and post-treatment surveillance for eoCRC patients. CONCLUSIONS: The DIRECt group produced the first consensus recommendations on eoCRC. All statements should be considered together with the accompanying comments and literature reviews. We highlighted areas where research should be prioritized. These guidelines represent a useful tool for clinicians caring for patients with eoCRC.publishedVersionPeer reviewe

Persistent pandemic demand for elective orthopedic surgery despite patient anxieties regarding COVID-19 in at-risk populations

Introduction: Even though the pandemic has had a documented impact on the outcomes of orthopedic surgery, the patient perspective and anxieties are not well addressed in the literature. Methods: A new COVID-focused patient survey on their perspective regarding orthopedic care has been formulated and investigated in 206 patients, including information regarding demographics and relevant health history. To aid our understanding, clinical practice trends were collected to better understand the impact on surgical volume and associated rebound after a catastrophic global event like a pandemic. Results: Patients with public insurance, hypertension, unemployed, or low health levels, were moderately worried about contracting and surviving Covid-19, but still prioritized their orthopedic care despite the associated risks. A typical orthopedic practice dropped 30–40 % of visits between week 5 and 7 of Covid-19. Telehealth visits comprised 20 % of visits. Discussion: Despite the pandemic impact and associated anxieties, the demand for orthopedic surgery persists both on the patient and healthcare sides. The impact and understanding of population dynamics are critical for future preparation and likely re-organization of healthcare systems such as increased telehealth utilization in orthopedics

Propagation of ultrasound in aqueous foams : bubble size dependence and resonance effects.

International audienceWe report experimental results on the propagation of ultrasonic waves (at frequencies in the range of 40 kHz) in aqueous foams. Monitoring the acoustics of the foams as they age, i.e. as the mean bubble radius increases by coarsening, we recover at short times some trends that are already known: decrease of the speed of sound and increase of attenuation. At long times, we have identified, for the first time, robust non-monotonic behaviors of the speed of sound and attenuation, associated with a critical bubble size, which decreases at increasing frequency. The experimental features appear to be surprisingly reminiscent of the Minnaert resonance known for a single isolated bubble in a fluid. Transposing the Minnaert theoretical framework to the limit of a dense packing of bubbles gives some qualitative agreement with the data, but still cannot explain quantitatively the measured properties

Green Steel Tracker

The Green Steel Tracker aims to support decision makers in policy and industry, academia as well as civil society, by tracking public announcements of low-carbon investments in the steel industry and presenting them transparently in one place

The lactonase BxdA mediates metabolic adaptation of maize root bacteria to benzoxazinoids

Root exudates contain secondary metabolites that affect the plant’s root microbiome. How microbes cope with these bioactive compounds, and how this ability shapes root microbiomes remain largely unknown. We investigated how maize root bacteria metabolise benzoxazinoids, the main specialised metabolites of maize. Diverse and abundant bacteria metabolised the major compound (6-methoxy-benzoxazolin-2-one, MBOA) in the maize rhizosphere to 2-amino-7-methoxyphenoxazin-3-one (AMPO). By contrast, bacteria isolated from Arabidopsis, which does not produce benzoxazinoids, were unable to metabolise MBOA. Among Microbacteria strains, this differential metabolisation allowed to identify a conserved gene cluster containing the lactonase bxdA. BxdA converts MBOA to AMPO in vitro and we show that this capacity provided bacteria a growth benefit under carbon-limiting conditions. Together these results reveal that maize root bacteria - through BxdA - are metabolically adapted to the benzoxazinoids of their host. We propose that metabolic adaptation to plant-specialised compounds shapes root bacterial communities across the plant kingdom