837 research outputs found

    Multi-microjoule GaSe-based mid-infrared optical parametric amplifier with an ultra-broad idler spectrum covering 4.2-16 {\mu}m

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    We report a multi-microjoule, ultra-broadband mid-infrared optical parametric amplifier based on a GaSe nonlinear crystal pumped at ~2 {\mu}m. The generated idler pulse has a flat spectrum spanning from 4.5 to 13.3 {\mu}m at -3 dB and 4.2 to 16 {\mu}m in the full spectral range, with a central wavelength of 8.8 {\mu}m. The proposed scheme supports a sub-cycle Fourier-transform-limited pulse width. A (2+1)-dimensional numerical simulation is employed to reproduce the obtained idler spectrum. To our best knowledge, this is the broadest -3 dB spectrum ever obtained by optical parametric amplifiers in this spectral region. The idler pulse energy is ~3.4 {\mu}J with a conversion efficiency of ~2% from the ~2 {\mu}m pump to the idler pulse.Comment: 5 pages, 5 figure

    Carbapenemase-Producing Escherichia coli among Humans and Backyard Animals

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    Background: The rapidly increasing dissemination of carbapenem-resistant Enterobacteriaceae (CRE) in both humans and animals poses a global threat to public health. However, the transmission of CRE between humans and animals has not yet been well studied. Objectives: We investigated the prevalence, risk factors, and drivers of CRE transmission between humans and their backyard animals in rural China. Methods: We conducted a comprehensive sampling strategy in 12 villages in Shandong, China. Using the household [residents and their backyard animals (farm and companion animals)] as a single surveillance unit, we assessed the prevalence of CRE at the household level and examined the factors associated with CRE carriage through a detailed questionnaire. Genetic relationships among human- and animal-derived CRE were assessed using whole-genome sequencing–based molecular methods. Results: A total of 88 New Delhi metallo-β-lactamases –type carbapenem-resistant Escherichia coli (NDM-EC), including 17 from humans, 44 from pigs, 12 from chickens, 1 from cattle, and 2 from dogs, were isolated from 65 of the 746 households examined. The remaining 12 NDM-EC were from flies in the immediate backyard environment. The NDM-EC colonization in households was significantly associated with a) the number of species of backyard animals raised/kept in the same household, and b) the use of human and/or animal feces as fertilizer. Discriminant analysis of principal components (DAPC) revealed that a large proportion of the core genomes of the NDM-EC belonged to strains from hosts other than their own, and several human isolates shared closely related core single-nucleotide polymorphisms and blaNDM genetic contexts with isolates from backyard animals. Conclusions: To our knowledge, we are the first to report evidence of direct transmission of NDM-EC between humans and animals. Given the rise of NDM-EC in community and hospital infections, combating NDM-EC transmission in backyard farm systems is needed. https://doi.org/10.1289/EHP525

    Numerical Simulation of Parallel Cutting with Different Number of Empty Holes

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    The cutting blasting plays a key role in rock excavation construction, which determines the blasting effect and efficiency of the entire blasting project. In the cutting blasting, parallel holes are often used as the auxiliary free surface and the compensation space of blasting rock, and the empty holes have a great influence on the blasting effect. In this paper, Ansys/Ls-Dyna finite element analysis software is carried out to simulate four models with different number of empty holes. The simulation results show that the stronger the guiding effect of the empty holes on the crack propagation, the more obvious the inhibition effect on the crack in the remaining direction. The initial crack near the empty hole is generated by the continuous action of the stress wave, and the empty hole promotes the propagation of the explosion stress wave. The inconsistent guiding directions of adjacent empty holes are one of the reasons for the unsatisfactory blasting effect of multiple small diameter empty holes. The closer the empty hole is to the blasthole, the larger the maximum principal stress. By comparing the results of calculation with the numerical simulation, it is verified that the maximum principal stress near the empty hole is similar and the change rule is consistent. The above research has reference meaning to the location of the hollow hole in the actual blasting construction and the density of the empty hole

    Sub-layer Correlation of Quantou Ⅳ Formation of the Lower Cretaceous in Haituozi Area of Songliao Basin

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    Fluvial-flood plain facies are developed at lower-mid Quantou Ⅳ Formation, and delta front - shallow lake facies are developed at the upper formation in Haituozi area of Southern Songliao Basin. Channel sand bodies are good oil and gas reservoirs, but the distribution of sand is not clear, which has become a key factor restricting oil and gas development. No less than 100 wells data of logging, some data of drilling, cores and testing are collected and used in correlation, firstly 5 roughly provenance direction and 5 crosscutting provenance direction sections were selected in the area, with high resolution sequence stratigraphic analysis, Quantou Ⅳ Formation is subdivided into 4 sequences (corresponding to the fifth order cycle sequence, are respectively called cycle A, B, C and D), sequence stratigraphic framework were established. Then the similarity of facies association characteristics in base level change, consistency of reservoir fluid properties, isochronous maximum flooding surface in a certain area, different stages of overlay channels are took full account in the operation of sub-layer correlation. In the end 3 sub-layers are divided from cycle A , 3 sub-layers divided from cycle B, 5 sub-layers from cycle C, and cycles D corresponds to a sub-layer, Quantou Ⅳ Formation is divided into 12 sub-layers, which lays good foundation for the production and development.Key words: High resolution sequence stratigraphy; Sub-layer correlation; Songliao basin; Haituozi area; Quantou Ⅳ Formatio

    A multi-level quantitative analysis method on the scale, shape and quantity of rockeries in Chinese classical gardens: taking Wanfang Anhe rockery in the Old Summer Palace as an example

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    Currently, the use of digital technology for the protection and research of cultural heritage has become a trend in this field. Rockeries in Chinese classical gardens have become an important cultural heritage type because of their unique shape, ingenious skills and rich connotations. Based on relevant historical information and 3D digital technology, this paper puts forward a multi-level quantitative analysis method on the scale, shape and quantity of rockeries in Chinese classical gardens, aiming at exploring the objective description and quantitative analysis path of rockeries at different levels.This method develops four levels: overall, regional, hierarchical, and individual and their corresponding quantitative contents, which in turn enable data extraction and analysis of the rockery through the different levels. The proposed method was applied to seven different Chinese classical garden rockeries, and taking Wanfang Anhe Rockery in the Old Summer Palace as an example for objective and comprehensive quantitative analysis and verification.The results show that this method is feasible and effective for quantitative analysis of the scale, shape and quantity of rockeries, which can help understand the basic background of stone rockeries and enhance a refined understanding of stone rockery construction, thereby providing data for preventive protection and informatization management of stone rockeries. The 3D rockery model database based on the overall, regional, hierarchical and individual quantitative analysis and numbering method brings a good application prospect for preventive protection and informatization management of the rockery

    GTNet: Generative Transfer Network for Zero-Shot Object Detection

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    We propose a Generative Transfer Network (GTNet) for zero shot object detection (ZSD). GTNet consists of an Object Detection Module and a Knowledge Transfer Module. The Object Detection Module can learn large-scale seen domain knowledge. The Knowledge Transfer Module leverages a feature synthesizer to generate unseen class features, which are applied to train a new classification layer for the Object Detection Module. In order to synthesize features for each unseen class with both the intra-class variance and the IoU variance, we design an IoU-Aware Generative Adversarial Network (IoUGAN) as the feature synthesizer, which can be easily integrated into GTNet. Specifically, IoUGAN consists of three unit models: Class Feature Generating Unit (CFU), Foreground Feature Generating Unit (FFU), and Background Feature Generating Unit (BFU). CFU generates unseen features with the intra-class variance conditioned on the class semantic embeddings. FFU and BFU add the IoU variance to the results of CFU, yielding class-specific foreground and background features, respectively. We evaluate our method on three public datasets and the results demonstrate that our method performs favorably against the state-of-the-art ZSD approaches.Comment: Accepted by AAAI 202

    Sleep duration and age-related macular degeneration: a cross-sectional and Mendelian randomization study

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    PurposeTo investigate the association between sleep duration and age-related macular degeneration (AMD).DesignCross-sectional study, bidirectional two-sample Mendelian randomization (MR). For cross-sectional analysis, we used survey data of 5,481 participants aged ≥40 years from the 2005 to 2008 National Health and Nutrition Examination Survey (NHANES). For MR analysis, we used sleep- and AMD-associated genome-wide association studies (GWAS) data involving large populations.MethodsThe association between sleep duration and AMD was assessed using logistic regression models. For MR analysis, the primary approach for MR analysis was the inverse-variance weighted (IVW) method.ResultsIn cross-sectional analysis, after adjusting for multiple covariates, short sleep duration (SSD) was found to be associated with increased risk of early AMD [odds ratio (OR) = 1.364, P = 0.036). MR analysis supported the results of cross-sectional analysis: SSD increases the risk of early AMD (β = 0.102, IVW-P = 0.003).ConclusionOur findings provide the evidence supporting the association between sleep deficiency and higher risk of AMD. Further studies are required to confirm our findings and elucidate the mechanisms underlying this association

    Joint association of vitamin D deficiency and sleep disorders with cardiovascular mortality: a prospective cohort study

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    PurposeVitamin D deficiency and sleep disorders may independently contribute to increased mortality, but the combined effects of these two factors on mortality remain unknown. This study aimed to investigate both the separate and joint effects of vitamin D deficiency and sleep disorders on cardiovascular disease mortality, as well as all-cause mortality and cancer mortality.MethodsWe analyzed data from 24,566 adults in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. Sleep disorders were assessed using self-report questionnaires, and vitamin D levels were measured through serum total 25-hydroxyvitamin D [25(OH)D]. Cox proportional hazards models were employed to evaluate the associations between separate and joint effects of vitamin D deficiency and sleep disorders with mortality outcomes.ResultsOver a median follow-up of 9.08 years, we included a total of 24,566 individuals, in this study. Among them, 2,776 cases were all-cause deaths, 858 were cardiovascular disease deaths, and 644 were cancer deaths. We found that Vitamin D deficiency was independently associated with an increased risk of all-cause mortality, while sleep disorders were similarly associated with a higher risk of all-cause mortality. Notably, participants with both vitamin D deficiency and sleep disorders exhibited a significantly higher risk of all-cause mortality (HR, 2.31; 95% CI: 1.36–3.91) and cardiovascular mortality (HR, 2.39; 95% CI, 1.03–5.58) compared to those with only one or neither risk factor, even after adjusting for potential confounders.ConclusionOur study highlights that the combination of vitamin D deficiency and sleep disorders was associated with an increased risk of all-cause and cardiovascular mortality in adults. These findings might help to refine dietary and lifestyle intervention strategies for this population
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