Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms. Nonstationarity has been difficult to quantify due to the small ...spatial and temporal scales. We use the closely spaced (subgyroscale), high-time-resolution measurements from one rapid crossing of Earth's quasiperpendicular bow shock by the Magnetospheric Multiscale (MMS) spacecraft to compare competing nonstationarity processes. Using MMS's high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples.
The fundamental building blocks of the proton-quarks and gluons-have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and ...their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin
. The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force
. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter-antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter-antimatter quark pair annihilates. In this picture of quark-antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton
. Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results
, and point to future measurements that can distinguish between these mechanisms.
Summary
Background
The risk factors for gastrointestinal bleeding (GIB) in clopidogrel users have not been identified.
Aim
To clarify whether clopidogrel use is a risk factor for upper GIB (UGIB) and ...lower GIB (LGIB) and identify the risk factors in clopidogrel users.
Methods
Using the National Health Insurance Research Database of Taiwan, 3238 clopidogrel users and 12 952 age‐, sex‐, and enrolment time‐matched controls in a 1:4 ratio were extracted for comparison from a cohort dataset of 1 000 000 randomly sampled subjects. Cox proportional hazard regression models were used to identify the independent risk factors for UGIB and LGIB in all enrollees and clopidogrel users after adjustments for age, gender, comorbidity i.e., coronary artery disease, hypertension, diabetes, chronic obstructive pulmonary disease, chronic kidney disease (CKD), cirrhosis, uncomplicated peptic ulcer disease, and peptic ulcer bleeding (PUB), and medications e.g., nonsteroidal anti‐inflammatory drugs (NSAIDs), cyclooxygenase‐2 inhibitors, aspirin, steroids, selective serotonin reuptake inhibitors (SSRIs), warfarin and alendronate.
Results
Cox proportional hazard regression analysis showed that use of clopidogrel increased the risk of UGIB hazard ratio (HR): 3.66; 95% confidence interval (CI): 2.96–4.51 and LGIB HR: 3.52, 95% CI: 2.74–4.52. Age, CKD, PUB history, use of aspirin and NSAIDs were independent risk factors for UGIB in the clopidogrel users. Age, CKD, PUB history, use of aspirin and SSRIs were independent risk factors for LGIB.
Conclusions
In clopidogrel users, age, CKD, PUB history, use of aspirin and NSAIDs are independent risk factors for UGIB; age, CKD, PUB history, use of aspirin and SSRIs are independent risk factors for LGIB.
•Identify optimal torrefaction and densification conditions for torrefied pellet production.•Quantify increased heating value and decreased moisture uptake for torrefied pellets.•Quantify increased ...compression energy consumption and decreased density of torrefied pellets.•Recommend high die temperature and sample preconditioning for torrefied pellet production.
Torrefaction and densification of British Columbia (BC) softwoods, including pine, fir, spruce, SPF (a mixture of spruce, pine and fir) and pine bark, have been conducted for the production of high quality torrefied wood pellets. A bench-scale fixed bed tubular reactor was used for the torrefaction test at temperatures of 240–340°C. Densification was conducted in a press machine in order to identify the suitable conditions for making strong torrefied pellets. Results showed that the mass loss of BC softwood mainly depended on the torrefaction temperature and time. The heating value of torrefied sawdust particles had a close relationship with the mass loss, increasing with increasing the severity of torrefaction. It was more difficult to compress torrefied samples into strong pellets than the raw material under the same conditions as used for making the control (regular and non-torrefied) pellets, and either a higher die temperature or adding moisture into torrefied particles could improve the compression process. The moisture content of torrefied pellets prepared in this study was lower than control pellets, and the density of torrefied pellets was slightly lower than control pellets. At the same time, more energy was consumed for compacting torrefied softwood particles into pellets. Increasing torrefaction severity increased the heating value and decreased the moisture uptake of torrefied pellets, but decreased the energy yield and the hardness of torrefied pellets. Considering the quality of torrefied pellets, the optimal torrefaction condition appeared to be around 30% mass loss, which gave a 20% increase in pellet higher heating value and a reasonable low water update rate. The suitable densification conditions for torrefied softwoods corresponded to a die temperature of 170–230°C for unconditioned samples, or about 110°C for samples preconditioned to ∼10% moisture content.
This paper presents a community effort to develop good practice guidelines for the validation of global coarse-scale satellite soil moisture products. We provide theoretical background, a review of ...state-of-the-art methodologies for estimating errors in soil moisture data sets, practical recommendations on data pre-processing and presentation of statistical results, and a recommended validation protocol that is supplemented with an example validation exercise focused on microwave-based surface soil moisture products. We conclude by identifying research gaps that should be addressed in the near future.
•Satellite soil moisture validation methods are reviewed•Community-agreed validation good practice guidelines are presented•A standardized satellite soil moisture validation protocol is provided
Metastatic lung cancer is one of the most lethal forms of cancer and molecular pathways driving metastasis are still not clearly elucidated. Metastatic cancer cells undergo an epithelial-mesenchymal ...transition (EMT) where they lose their epithelial properties and acquire a migratory and invasive phenotype. Here we identify that the expression of microRNAs from the miR-200 family and the miR-183~96~182 cluster are significantly co-repressed in non-small cell lung cancer cell lines and primary tumors from multiple TCGA dataset with high EMT scores. Ectopic expression of the miR-183~96~182 cluster inhibited cancer cell migration and invasion, whereas its expression was tightly modulated by miR-200. We identified Foxf2 as a common, novel and direct target of both these microRNA families. Foxf2 expression tightly correlates with the transcription factor Zeb1 and is elevated in mesenchymal-like metastatic lung cancer cells. Foxf2 expression induced robust EMT, migration, invasion and metastasis in lung cancer cells, whereas Foxf2 inhibition significantly repressed these phenotypes. We also demonstrated that Foxf2 transcriptionally represses E-cadherin and miR-200, independent of Zeb1, to form a double-negative feedback loop. We, therefore, identified a novel mechanism whereby the miR-200 family and the miR-183~96~182 cluster inhibit lung cancer invasion and metastasis by targeting Foxf2.
Nature inspired flow field designs for proton exchange membrane fuel cells (PEMFCs) are a relatively recent development in the technology evolution. These novel designs have the potential to show ...dramatic performance improvements by effective distribution of reactant gases without water flooding. Optimization of a flow field requires balancing gas distribution, water management, electron transport, pressure drop and manufacturing simplicity. Computational fluid dynamics (CFD) simulation studies are a useful tool for evaluating nature inspired flow field designs; however, the predictions should be used with caution until validated by an experimental study. Nature inspired flow field designs can be generated using formal mathematical algorithms or by making heuristic modifications to existing natural structures. This paper reviews the current state of nature inspired PEMFC flow field designs and discusses the challenges in evaluating these designs.
► This manuscript deals with the trend on flow field design in the recent years. ► CFD modeling is a useful design tool but limitations should be understood. ► Nature inspired designs are one of the potential optimization approaches.
Abstract Background Surgical excision of papillary breast lesions with atypia diagnosed using core needle biopsy (CNB) has been accepted; however, the management of benign papillary lesions (without ...atypia) has been controversial. The purpose of this study was to evaluate the surgical outcome of nonmalignant papillary lesions diagnosed by ultrasound-guided 14-gauge CNB, and to establish clear guidelines on management of these lesions. Methods We retrospectively identified 268 nonmalignant papillary breast lesions, including 203 benign lesions and 65 atypical lesions, diagnosed by CNB and subsequently surgically excised in 250 women at our institution between July 2004 and October 2010. For each lesion, medical records and radiologic and pathologic reports were reviewed and coded. We compared the histological upgrade among the collected variables. Results On histological examination after surgical excision, 15.4% atypical papillary lesions and 5.9% benign lesions were upgraded to malignant, and 20.2% benign lesions were upgraded to atypical. Atypia ( P = 0.015) was significantly associated with malignant upgrade at excision. No clinical or radiologic variable was helpful in predicting the possibility of histological upgrade of CNB-diagnosed nonmalignant papillary lesions. Conclusions Nonmalignant papillary lesions diagnosed with CNB showed an unacceptable pathological upgrade rate after excision. Therefore, surgical excision should be performed for all papillary lesions of the breast for definitive diagnosis.
A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9 GW(th) reactors were ...detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3) eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.
This systematic review and meta-analysis estimated the global, regional prevalence, and risk factors of osteoporosis. Prevalence varied greatly according to countries (from 4.1% in Netherlands to ...52.0% in Turkey) and continents (from 8.0% in Oceania to 26.9% in Africa). Osteoporosis is a common metabolic bone disorder in the elderly, usually resulting in bone pain and an increased risk of fragility fracture, but few summarized studies have guided global strategies for the disease. Therefore, we pooled the epidemiologic data to estimate the global, regional prevalence, and potential risk factors of osteoporosis. We conducted a comprehensive literature search through PubMed, EMBASE, Web of Science, and Scopus, to identify population-based studies that reported the prevalence of osteoporosis based on the World Health Organization (WHO) criteria. Meta-regression and subgroup analyses were used to explore the sources of heterogeneity. The study was registered in the PROSPERO database (CRD42021285555). Of the 57,933 citations evaluated, 108 individual studies containing 343,704 subjects were included. The global prevalence of osteoporosis and osteopenia was 19.7% (95%CI, 18.0%–21.4%) and 40.4% (95%CI, 36.9%–43.8%). Prevalence varied greatly according to countries (from 4.1% in Netherlands to 52.0% in Turkey) and continents (from Oceania 8.0% to 26.9% in Africa). The prevalence was higher in developing countries (22.1%, 95%CI, 20.1%–24.1%) than in developed countries (14.5%, 95%CI, 11.5%–17.7%). Our study indicates a considerable prevalence of osteoporosis among the general population based on WHO criteria, and the prevalence varies substantially between countries and regions. Future studies with robust evidence are required to explore risk factors to provide effective preventive strategies for the disease.
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