60 research outputs found
Exploring the Influence of Wind Turbine\u27s Blades on Its Output and Efficiency
Wind turbines are machines that convert wind energy into electricity. The efficiency of this conversion is measured by comparing the incoming wind\u27s speed and the output power. This paper focuses on how the properties of blades affect the output and power of wind turbines. The attributes of turbine blades that affect output and efficiency, such as blade size and angle of entry, are considerable. Although results generally match with theory models, we find a size limit with blade length
Analysis of Water Vapour Feedback and its Impact on Surface Temperature
The accumulation of greenhouse gases is the main reason for the global warming process. Water vapour, being one of the most abundant and powerful greenhouse gas, strongly influences the warming process in multiple ways. Despite being a greenhouse gas itself, the amount of water vapour in the atmosphere is directly related to the surface temperature of the earth. To understand the global warming process, a deeper look into water vapour and its unique positive feedback mechanism is meaningful. This paper will discuss the mechanism of water vapour feedback, the equilibrium established between the content of water vapour in the air and the surface temperature of the earth. In addition, this study will calculate the time scale and magnitude of the response of water vapour to varying (in real cases increasing) surface temperature, and qualitatively analyse how water vapour feedback would affect the global warming process by serving as an amplifier for the greenhouse effect. These results establish a mathematical model for water vapour feedbackβs impact on surface temperature rise and could be used as a starting point for lab experiments and more complex analysis
Power analysis for cluster randomized trials with continuous co-primary endpoints
Pragmatic trials evaluating health care interventions often adopt cluster
randomization due to scientific or logistical considerations. Previous reviews
have shown that co-primary endpoints are common in pragmatic trials but
infrequently recognized in sample size or power calculations. While methods for
power analysis based on () binary co-primary endpoints are
available for CRTs, to our knowledge, methods for continuous co-primary
endpoints are not yet available. Assuming a multivariate linear mixed model
that accounts for multiple types of intraclass correlation coefficients
(endpoint-specific ICCs, intra-subject ICCs and inter-subject between-endpoint
ICCs) among the observations in each cluster, we derive the closed-form joint
distribution of treatment effect estimators to facilitate sample size and
power determination with different types of null hypotheses under equal cluster
sizes. We characterize the relationship between the power of each test and
different types of correlation parameters. We further relax the equal cluster
size assumption and approximate the joint distribution of the treatment
effect estimators through the mean and coefficient of variation of cluster
sizes. Our simulation studies with a finite number of clusters indicate that
the predicted power by our method agrees well with the empirical power, when
the parameters in the multivariate linear mixed model are estimated via the
expectation-maximization algorithm. An application to a real CRT is presented
to illustrate the proposed method
Comparison of three magnetization transfer ratio parameters for assessment of intestinal fibrosis in patients with Crohnβs disease
Unified Medical Image Pre-training in Language-Guided Common Semantic Space
Vision-Language Pre-training (VLP) has shown the merits of analysing medical
images, by leveraging the semantic congruence between medical images and their
corresponding reports. It efficiently learns visual representations, which in
turn facilitates enhanced analysis and interpretation of intricate imaging
data. However, such observation is predominantly justified on single-modality
data (mostly 2D images like X-rays), adapting VLP to learning unified
representations for medical images in real scenario remains an open challenge.
This arises from medical images often encompass a variety of modalities,
especially modalities with different various number of dimensions (e.g., 3D
images like Computed Tomography). To overcome the aforementioned challenges, we
propose an Unified Medical Image Pre-training framework, namely UniMedI, which
utilizes diagnostic reports as common semantic space to create unified
representations for diverse modalities of medical images (especially for 2D and
3D images). Under the text's guidance, we effectively uncover visual modality
information, identifying the affected areas in 2D X-rays and slices containing
lesion in sophisticated 3D CT scans, ultimately enhancing the consistency
across various medical imaging modalities. To demonstrate the effectiveness and
versatility of UniMedI, we evaluate its performance on both 2D and 3D images
across 10 different datasets, covering a wide range of medical image tasks such
as classification, segmentation, and retrieval. UniMedI has demonstrated
superior performance in downstream tasks, showcasing its effectiveness in
establishing a universal medical visual representation
Genome-wide association study on serum alkaline phosphatase levels in a Chinese population
Background: Serum alkaline phosphatase (ALP) is a complex phenotype influenced by both genetic and environmental factors. Recent Genome-Wide Association Studies (GWAS) have identified several loci affecting ALP levels; however, such studies in Chinese populations are limited. We performed a GWAS analyzing the association between 658,288 autosomal SNPs and serum ALP in 1,461 subjects, and replicated the top SNPs in an additional 8,830 healthy Chinese Han individuals. The interactions between significant locus and environmental factors on serum ALP levels were further investigated. Results: The association between ABO locus and serum ALP levels was replicated (P = 2.50 Γ 10-21, 1.12 Γ 10-56 and 2.82 Γ 10-27 for SNP rs8176720, rs651007 and rs7025162 on ABO locus, respectively). SNP rs651007 accounted for 2.15% of the total variance of serum ALP levels independently of the other 2 SNPs. When comparing our findings with previously published studies, ethnic differences were observed across populations. A significant interaction between ABO rs651007 and overweight and obesity was observed (FDR for interaction was 0.036); for individuals with GG genotype, those with normal weight and those who were overweight or obese have similar serum ALP concentrations; minor allele A of rs651007 remarkably reduced serum ALP levels, but this effect was attenuated in overweight and obese individuals. Conclusions: Our findings indicate that ABO locus is a major determinant for serum ALP levels in Chinese Han population. Overweight and obesity modifies the effect of ABO locus on serum ALP concentrations
Neural network-based model for evaluating inert nodules and volume doubling time in T1 lung adenocarcinoma: a nested caseβcontrol study
ObjectiveThe purpose of this study is to establish model for assessing inert nodules predicting nodule volume-doubling.MethodsA total of 201 patients with T1 lung adenocarcinoma were analysed retrospectively pulmonary nodule information was predicted by an AI pulmonary nodule auxiliary diagnosis system. The nodules were classified into two groups: inert nodules (volume-doubling time (VDT)>600 days n=152) noninert nodules (VDT<600 days n=49). Then taking the clinical imaging features obtained at the first examination as predictive variables the inert nodule judgement model <sn</sn>>(INM) volume-doubling time estimation model (VDTM) were constructed based on a deep learning-based neural network. The performance of the INM was evaluated by the area under the curve (AUC) obtained from receiver operating characteristic (ROC) analysis the performance of the VDTM was evaluated by R2(determination coefficient).ResultsThe accuracy of the INM in the training and testing cohorts was 81.13% and 77.50%, respectively. The AUC of the INM in the training and testing cohorts was 0.7707 (95% CI 0.6779-0.8636) and 0.7700 (95% CI 0.5988-0.9412), respectively. The INM was effective in identifying inert pulmonary nodules; additionally, the R2 of the VDTM in the training cohort was 0.8008, and that in the testing cohort was 0.6268. The VDTM showed moderate performance in estimating the VDT, which can provide some reference during a patientsβ first examination and consultationConclusionThe INM and the VDTM based on deep learning can help radiologists and clinicians distinguish among inert nodules and predict the nodule volume-doubling time to accurately treat patients with pulmonary nodules
The Role of Polymeric Immunoglobulin Receptor in Inflammation-Induced Tumor Metastasis of Human Hepatocellular Carcinoma
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