108 research outputs found

    Implementing hybrid simulations that integrate DES+SD in Python

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    Implementation of hybrid simulation is not well documented, and often obscured behind commercial software packages. Here two implementation approaches for integrating discrete event simulation and systems dynamics are presented in an open, reproducible framework, built with the Ciw library in Python. These two implementation approaches, denoted here by DES⊂SD and SD⊂DES, correspond to two different process environments for DES+SD hybrid simulations. The models contribute to a collection of accessible and transparent hybrid simulations to be reproduced, scrutinised, built upon, and further developed. This paper also presents discussion on the lessons learned from these implementations, including the appropriateness of the models for different process environments, their ability to capture the full variability of a system, and subtleties in their synchronicity

    Global Pattern and Change of Cropland Soil Organic Carbon during 1901-2010: Roles of Climate, Atmospheric Chemistry, Land Use and Management

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    Soil organic carbon (SOC) in croplands is a key property of soil quality for ensuring food security and agricultural sustainability, and also plays a central role in the global carbon (C) budget. When managed sustainably, soils may play a critical role in mitigating climate change by sequestering C and decreasing greenhouse gas emissions into the atmosphere. However, the magnitude and spatio-temporal patterns of global cropland SOC are far from well constrained due to high land surface heterogeneity, complicated mechanisms, and multiple influencing factors. Here, we use a process-based agroecosystem model (DLEM-Ag) in combination with diverse spatially-explicit gridded environmental data to quantify the long-term trend of SOC storage in global cropland area during 1901-2010 and identify the relative impacts of climate change, elevated CO2, nitrogen deposition, land cover change, and land management practices such as nitrogen fertilizer use and irrigation. Model results show that the total SOC and SOC density in the 2000s increased by 125% and 48.8%, respectively, compared to the early 20th century. This SOC increase was primarily attributed to cropland expansion and nitrogen fertilizer use. Factorial analysis suggests that climate change reduced approximately 3.2% (or 2,166 Tg C) of the total SOC over the past 110 years. Our results indicate that croplands have a large potential to sequester C through implementing better land use management practices, which may partially offset SOC loss caused by climate change

    Efficacy Dependence of Photodynamic Therapy Mediated by Upconversion Nanoparticles: Subcellular Positioning and Irradiation Productivity

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136433/1/smll201602053_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136433/2/smll201602053-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136433/3/smll201602053.pd

    SdPI, The First Functionally Characterized Kunitz-Type Trypsin Inhibitor from Scorpion Venom

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    Background: Kunitz-type venom peptides have been isolated from a wide variety of venomous animals. They usually have protease inhibitory activity or potassium channel blocking activity, which by virtue of the effects on predator animals are essential for the survival of venomous animals. However, no Kunitz-type peptides from scorpion venom have been functionally characterized. Principal Findings: A new Kunitz-type venom peptide gene precursor, SdPI, was cloned and characterized from a venom gland cDNA library of the scorpion Lychas mucronatus. It codes for a signal peptide of 21 residues and a mature peptide of 59 residues. The mature SdPI peptide possesses a unique cysteine framework reticulated by three disulfide bridges, different from all reported Kunitz-type proteins. The recombinant SdPI peptide was functionally expressed. It showed trypsin inhibitory activity with high potency (Ki = 1.6610 27 M) and thermostability. Conclusions: The results illustrated that SdPI is a potent and stable serine protease inhibitor. Further mutagenesis and molecular dynamics simulation revealed that SdPI possesses a serine protease inhibitory active site similar to other Kunitztype venom peptides. To our knowledge, SdPI is the first functionally characterized Kunitz-type trypsin inhibitor derive

    The seeds of ecological recovery in urbanization-Spatiotemporal evolution of ecological resiliency of Dianchi Lake Basin, China

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    As a result of years of monitoring the ecological resiliency of natural areas and cities, it has become clear that it is both important and often feasible to implement ecological and environmental restoration in conjunction with ongoing processes of landscape change development and urbanization. Ecological resiliency and spatiotemporal evolution studies can objectively reveal the resiliency of ecosystems to external disturbances. Ecological monitoring and assessment can also help planners understand regional ecological spatial differentiation patterns and provided data support for planning. In this paper we have analyzes quantitatively the interrelationships of ecological factors in Dianchi Lake Basin (DLB) over the past 30 years and explored the spatial and temporal dynamics of ecological resiliency. Based on remote sensing images and primary data in 1995, 2005, 2010, 2015, 2018, and 2022, we used the center of gravity migration and kernel density analysis to explore the spatial and temporal changes of ecological resiliency. We built the overall resiliency evaluation system using entropy weight in the TOPSIS model, and finally simulate the future changes based on CA-Markov (CA-MC) model. The results show that from 1995 to 2022, the ecological resiliency of land use and vegetation cover in DLB decreased substantially. An important finding was that the ecological resiliency of riparian buffer zone and landscape pattern were generally increasing. The distribution of barycenter movement and kernel density of different levels of ecological resiliency differed significantly and showed fluctuating changes. The extreme low resiliency and extremely resilient areas shift to the northeast, the mildly resilient areas shift to the northwest, and the highly resilient areas shift to the southeast. The overall resiliency level of DLB is predicted to slowly increase from 2022 to 2030 by deduction of the CA-MC model. Our analysis suggests that the study of the evolution of regional ecological resiliency can provide a timely understanding of regional ecological evolution patterns and propose ecological protection strategies

    Bibliometric and visual analysis of intraoperative hypotension from 2004 to 2022

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    BackgroundIntraoperative hypotension (IOH) is a common complication occurring in surgical practice. This study aims to comprehensively review the collaboration and impact of countries, institutions, authors, journals, keywords, and critical papers on intraoperative hypotension from the perspective of bibliometric, and to evaluate the evolution of knowledge structure clustering and identify research hotspots and emerging topics.MethodsArticles and reviews related to IOH published from 2004 to 2022 were retrieved from the Web of Science Core Collection. Bibliometric analyses and visualization were conducted on Excel, CiteSpace, VOSviewer, and Bibliometrix (R-Tool of R-Studio).ResultsA total of 1,784 articles and reviews were included from 2004 to 2022. The number of articles on IOH gradually increased in the past few years, and peaked in 2021. These publications were chiefly from 1,938 institutions in 40 countries, led by America and China in publications. Sessler Daniel I published the most papers and enjoyed the highest number of citations. Analysis of the journals with the most outputs showed that most journals concentrated on perioperative medicine and clinical anesthesiology. Delirium, acute kidney injury and vasoconstrictor agents are the current and developing research hotspots. The keywords “Acute kidney injury”, “postoperative complication”, “machine learning”, “risk factors” and “hemodynamic instability” may also become new trends and focuses of the near future research.ConclusionThis study uses bibliometrics and visualization methods to comprehensively review the research on intraoperative hypotension, which is helpful for scholars to better understand the dynamic evolution of IOH and provide directions for future research

    Conservation tillage increases corn and soybean water productivity across the Ohio River Basin

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    Optimizing agricultural management practices is imperative for ensuring food security and building climate-resilient agriculture. The past several decades have witnessed the emergence of conservation tillage practices to combat soil erosion and degradation. However, the effects of conservation tillage on crop water productivity (CWP) remain uncertain, especially from a regional-scale perspective. Here, we used an improved process-based agroecosystem model (DLEM-Ag) to quantify the long-term effects of conservation tillage (e.g., no-tillage, NT; reduced tillage, RT) on CWP (defined as the ratio of crop productivity to evapotranspiration) of corn and soybean across the Ohio River Basin during 1979–2018. Our results revealed an average increase of 2.8% and 8.4% in CWP for corn and soybean, respectively, under the NT adoption scenario. Compared to the conventional tillage scenario, NT and RT would enhance CWP, primarily due to reductions in evapotranspiration, particularly evaporation. Further analysis suggested that, although NT and RT may decrease surface runoff, these practices could also increase subsurface drainage and nutrient loss from corn and soybean farmland via leaching. These results indicate that conservation tillage should be complemented with additional water and nutrient management practices to enhance soil water retention and optimize nutrient use in the region's cropland. Our findings also provide unique insights into optimizing management practices for other areas where conservation tillage is widely applied

    Proton pump inhibitors may enhance the risk of digestive diseases by regulating intestinal microbiota

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    Proton pump inhibitors (PPIs) are the most used acid-inhibitory drugs, with a wide range of applications in the treatment of various digestive diseases. However, recently, there has been a growing number of digestive complications linked to PPIs, and several studies have indicated that the intestinal flora play an important role in these complications. Therefore, developing a greater understanding of the role of the gut microbiota in PPI-related digestive diseases is essential. Here, we summarize the current research on the correlation between PPI-related digestive disorders and intestinal flora and establish the altered strains and possible pathogenic mechanisms of the different diseases. We aimed to provide a theoretical basis and reference for the future treatment and prevention of PPI-related digestive complications based on the regulation of the intestinal microbiota
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