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Multiplicity Results for Second Order Impulsive Differential Equations via Variational Methods 认领
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作者 Huanhuan Wang Dan Lu Huiqin Lu 《工程(英文)(1947-3931)》 2021年第2期82-93,共12页
In this paper we investigate a class of impulsive differential equations with Dirichlet boundary conditions. Firstly, we define new inner product of <img src="Edit_890fce38-e82b-4f36-be40-9d05e8119b88.png"... In this paper we investigate a class of impulsive differential equations with Dirichlet boundary conditions. Firstly, we define new inner product of <img src="Edit_890fce38-e82b-4f36-be40-9d05e8119b88.png" width="40" height="17" alt="" /> and prove that the norm which is deduced by the inner product is equivalent to the usual norm. Secondly, we construct the lower and upper solutions of (1.1). Thirdly, we obtain the existence of a positive solution, a negative solution and a sign-changing solution by using critical point theory and variational methods. Finally, an example is presented to illustrate the application of our main result. 展开更多
关键词 Impulsive Differential Equation Sign-Changing Solution Critical Point Theory Variational Method
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Epidemioclinics, Etiologies and Prognosis of Cardiogene Shock State in the Intensive Care Unit of the Cardiology Department of the G-Spot Hospital 认领
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作者 Mariam Sako Massama Konaté +15 位作者 Boubacar Sonfo Samba Sidibé Nouhoum Diallo Fatoumata Diarra Mamadou Diakité Coumba Adiaratou Thiam Asmao Keita Ibrahima Sangaré Hamidou Omar Bâ Youssouf Camara Yves Roland Koumaré Alou Sangaré Boureïma Dembélé Ami Diarra Souleymane Coulibaly Ichacka Minta 《心血管病(英文)》 2021年第1期20-24,共5页
<div style="text-align:justify;"> <strong>Objective</strong>: The work aimed to describe the etiological and evolutionary aspects of cardiogenic shock in the intensive care unit of the card... <div style="text-align:justify;"> <strong>Objective</strong>: The work aimed to describe the etiological and evolutionary aspects of cardiogenic shock in the intensive care unit of the cardiology department (USIC) of the G-spot hospital in Bamako,<span "=""> Mali. <b>Materials and Methods</b></span><span "="">: This was a descriptive cross-sectional study from January 1, 2018 to April 30, 2019 that included all patients admitted to the USIC during this period. Each patient benefited from individual data support with systematic recording of socio-demographic, clinical, complementary and therapeutic data and analyzed with the SOFTWARE SPSS 20.0 French version. <b>Results</b>: The study involved 40 patients out of 311 patients hospitalized in USIC, representing a hospital frequency of 12.86%. Males were the most affected (60%) with a sex ratio of 1.50. The modal class was 41</span> - 60 years with extremes at 18 years and 89 years. Cardiovascular risk factors were dominated by HTA (27.50%), diabetes and tobacco, each with 22.50%. The general signs were tachycardia (90%), oxygen desaturation (77.50%), impregnable blood pressure (62.50%), agitation (52.50%) and an oliguria (70%). At the electrocardiogram the rhythm was sinus (80%), it was an atrial fibrillation (15%), a ventricular tachycardia (10%) and signs of coronary ischemia (necrosis in 35% and ST over shifted in 20% of cases). At cardiac doppler ultrasound,the left ventricle was dilated (50%), the right cavities dilated (30%), segmental kinetic disorder (40%), the left ventricular systolic function (FEVG) impaired (75%) and valve disease (10%). Biology noted hyper-creatinemia (65%), hyper-glycemia (12.50%), anemia and hyponatremia with 20% frequency each. Among etiology,<span "=""> ischemic heart disease accounted for 57.50% followed by pulmonary embolism 20%, dilated valve cardiomyopathy 7.50% and chronic pulmonary heart 2.50%. The trend in the majority of cases was unfavorable with 60% of deaths. Chronic pulmonary heart and pulmonary embolism were the 展开更多
关键词 Cardiogenic Shock ETIOLOGY PROGNOSTIC USIC Hospital Point G
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电针肺经原络穴治疗大肠癌术后肠梗阻的临床观察 认领
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作者 龙莹 张子敬 +2 位作者 黄展明 陈佳芸 谢晓华 《广州中医药大学学报》 CAS 2021年第3期518-523,共6页
【目的】观察电针肺经原络穴治疗大肠癌术后肠梗阻的临床疗效。【方法】将60例大肠癌术后患者随机分为治疗组和对照组,每组各30例。对照组给予常规基础治疗,治疗组在对照组治疗的基础上,给予电针肺经原穴太渊、络穴列缺治疗。观察2组患... 【目的】观察电针肺经原络穴治疗大肠癌术后肠梗阻的临床疗效。【方法】将60例大肠癌术后患者随机分为治疗组和对照组,每组各30例。对照组给予常规基础治疗,治疗组在对照组治疗的基础上,给予电针肺经原穴太渊、络穴列缺治疗。观察2组患者术后肠鸣音恢复时间、首次排气时间、首次排便时间、恢复流质饮食时间以及术后住院时间,观察患者不良反应如腹胀腹痛、恶心呕吐、肺部感染等的发生情况,并评价其安全性。【结果】(1)治疗组患者的肠鸣音恢复时间、首次排气时间、首次排便时间、恢复流质饮食时间和术后住院时间均明显缩短,与对照组比较,差异有统计学意义(P<0.05)。(2)治疗过程中,治疗组发生腹胀腹痛1例、恶心呕吐2例,无肺部感染发生,不良反应总发生率为10.00%(3/30);对照组腹胀腹痛8例、恶心呕吐4例,肺部感染2例,不良反应总发生率为46.60%(14/30)。治疗组腹胀腹痛、恶心呕吐以及肺部感染的发生率明显减少,与对照组比较,差异有统计学意义(P<0.01)。【结论】电针肺经原络穴治疗大肠癌术后肠梗阻操作安全、简便,能明显地减少术后肠梗阻的发生率、减少患者术后的住院时间,无严重不良反应。 展开更多
关键词 电针 太渊穴 列缺穴 肠梗阻 大肠癌术后 临床观察
Environmental Risk Factors for Stomach Cancer in an African Setting about 193 Cases at the CHU Point G in Bamako/Mali 认领
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作者 Souleymane Sanogo Drissa Traoré +8 位作者 Mamadou Coulibaly Birama Togola Bréhima Bengaly Ousmane Ibréhima Touré Drissa Ouattara Bréhima Coulibaly Babou Ba Siaka Diallo Nouhoum Ongoiba 《外科学(英文)》 2021年第2期23-30,共8页
CHU (University Hospital Center) Point G: The department of surgery B is a surgical department of CHU Point G. The department is par excellence a reference department for cases of visceral surgery, cancer surgery, car... CHU (University Hospital Center) Point G: The department of surgery B is a surgical department of CHU Point G. The department is par excellence a reference department for cases of visceral surgery, cancer surgery, cardiovascular surgery, plastic and endocrinology surgery. As a reminder, the CHU Point G is the largest 3rd level referral hospital in Mali. <b><span style="font-family:Verdana;">Aim:</span></b><span style="font-family:Verdana;"> To study the environmental risk factors of stomach cancer in the B surgery department of the Point G University Hospital in Bamako. </span><b><span style="font-family:Verdana;">Patients and Methods:</span></b><span style="font-family:Verdana;"> We performed a cross-sectional study with retrospective collection from January 2008 to June 2018 (126 months). </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">We have identified 380 cases of digestive cancer, including 193 cases of stomach cancer </span><span style="font-family:Verdana;">o</span><span style="font-family:;" "=""><span style="font-family:Verdana;">r 50.79% of digestive cancers. The mean age of the patients was 57.21 ± 13 years. Male sex represented 55% (n = 106). Eating habits were dominated by the consumption of t<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">&ocirc;</span> with potash (cereal paste) with 64.76% (n = 185). The main methods of preserving meat and fish were curing and smoking with 57.51% (n = 111). Chronic smoking was found in 24.35% (n = 47), alcohol + tobacco consumption in 2.59% (n = 5). The low socio-economic class represented 126 cases or 65.38%. Housewives and cultivators were respectively 37.82% (n = 73) and 227.97% (n = 54). 20.20% (n = 39) had a history of epigastric pain. Epigastralgia was the most common functional sign with 84.5% of cases (n = 169). An epigastric mass was found in 72 patients or 37.3%. Adenocarcinoma represented 97.4% (n = 188). Palliative surgery concerned the majority of ou 展开更多
关键词 Stomach Cancer Environmental Risk Factors African Setting CHU Point G
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The Existence of Periodic Solutions of a Class of <i>n</i>-Degree Polynomial Differential Equations* 认领
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作者 Ni Hua 《应用数学(英文)》 2021年第1期32-57,共26页
This paper deals with a class of <em>n</em>-degree polynomial differential equations. By the fixed point theorem and mathematical analysis techniques, the existence of one (<em>n</em> is an odd... This paper deals with a class of <em>n</em>-degree polynomial differential equations. By the fixed point theorem and mathematical analysis techniques, the existence of one (<em>n</em> is an odd number) or two (<em>n</em> is an even number) periodic solutions of the equation is obtained. These conclusions have certain application value for judging the existence of periodic solutions of polynomial differential equations with only one higher-order term. 展开更多
关键词 n-Degree Polynomial Differential Equation Fixed Point Theory Periodic Solution
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On the (<i>r</i>,<i>φ</i>,<i>ψ</i>)-Suzuki Contraction for the Multi-Valued Mappings 认领
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作者 Zamir Selko 《应用数学与应用物理(英文)》 2021年第2期211-219,共9页
In this work we try to give a new contraction type in multi-valued mapping on complete metric spaces. We prove the existence of fixed point for (<i>r</i>,<i>φ</i>,<i>ψ</i>)-Suzuki... In this work we try to give a new contraction type in multi-valued mapping on complete metric spaces. We prove the existence of fixed point for (<i>r</i>,<i>φ</i>,<i>ψ</i>)-Suzuki contraction in such spaces. Around our paper, the function <i>ψ</i> is absolutely continuous, and in this case, the contraction proposed by as has a fixed point. 展开更多
关键词 Suzuki-Contraction Multi-Valued Mappings Fixed Point Theorem Absolutely Continuous Functions
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文章速递Improved VSVPWM Modulation Method for Three-level NPC Inverter in Rural Power Grid 认领
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作者 Li Ran Fang Jun-long +1 位作者 Wang Jun-fu Wang Guang-ya 《东北农业大学学报:英文版》 CAS 2021年第1期90-96,共7页
With the acceleration of agricultural electrification,a lot of nonlinear and shock loads appear in the rural power grid,and the resulting harmonic and reactive currents pollute the rural power grid more and more serio... With the acceleration of agricultural electrification,a lot of nonlinear and shock loads appear in the rural power grid,and the resulting harmonic and reactive currents pollute the rural power grid more and more seriously.To solve the above problem,three-level neutral point clamped(NPC)inverters have been widely used,but their development is greatly restricted by the defect of neutral point voltage imbalance.In this paper,an improved virtual space vector pulse width modulation(VSVPWM)was proposed.Firstly,the mathematical models of various space vectors were established,and the influence of various space vectors on neutral point voltage was analyzed.The sum of the vector current at the neutral point was zero and the voltage control at the neutral point was completed by.introducing the time offset into different switching times of the redundant small vector.This method was simple in design and avoided the redundant calculation of the traditional VSVPWM method and tedious switch sequence design.This balancing control strategy could greatly reduce the influence of virtual vectors on neutral point voltage and effectively control the low-frequency oscillation of neutral point voltage.The validity of the method was verified by establishing a matlab simulation model. 展开更多
关键词 rural power grid virtual space vector pulse width modulation neutral point clamped inverter neutral point voltage
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文章速递Barriers and Enablers That Influence Utilization of Ultrasound Screening Services among Antenatal Women in Kajiado and Kisii Counties Kenya 认领
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作者 Micah Matiang’i Koen Joosse +4 位作者 Priscillah Ngunju Colleta Kiilu Romy Harkx Marianne Hangelbroek Jarim Omogi 《临床诊断学期刊(英文)》 2021年第1期1-17,共17页
<b> Background: </b>The World Health Organization recommends to have all pregnant women to undergo an obstetric ultrasound scan before 24 weeks gestation. However, this has been a challenge as a result of ... <b> Background: </b>The World Health Organization recommends to have all pregnant women to undergo an obstetric ultrasound scan before 24 weeks gestation. However, this has been a challenge as a result of limited access to appropriate Point of Care Ultrasound Screening (POCUS) services in lower levels of developing countries’ Health Systems, cost of care, skills gap among care providers and unclear regulatory policy frameworks. Obstetric Ultrasound scan helps to confirm viability of a pregnancy, gestational age, multiple pregnancies and it also helps rule out fetal abnormalities early enough. <b>Methods: </b>One year after intervention, a cross-sectional study was carried in the two pilot counties of <i>Kisii </i>(rural) and <i>Kajiado </i>(peri-urban). This followed after selected midwives in the two counties were trained on basic obstetric ultrasound screening for ANC women. A total of 366 women who were either in their last phases of pregnancy or had delivered within three months before the survey were interviewed. Cumulatively, the 36 midwives had screened 1,250 mothers out of whom 18 high risk pregnancies were identified. Open Data Kit (ODK) was used to collect quantitative data and analysed using STATA version 15. Descriptive statistics were used to summarize the data test associations between variables. Bivariate and logistic regression was used to identify predictive variables, and ORs with 95% confidence intervals used to measure the strength of the associations. <b>Findings: </b>Slightly more than a third (36%) of the women had recently delivered. In total, Kisii (rural county) had a representation of 59% of the respondents. Half of the respondents were aged between 25 - 34 years, 55% of the women interviewed were housewives while 48% had secondary level of education. Only 21% of the women had undergone routine ultrasound screening before 24 weeks of gestation with the average distance travelled by majority (45%) of the respondents to access the POCUS service being 3 - 5 km. The need to confirm a pregnancy’s gestation was the major (68.1%) motivator for seeking the service in the two pilot counties. Employment status, household income, education level, pregnancy gestation and distance to the facility had a statistical significance (<i>P</i> < 0.05) with ultrasound utilization. Highest education level, pregnancy gestation and distance to the nearest ultrasound screening facility were found to significantly predict the likelihood of utilizing the ultrasound services (<i>P </i>< 0.05). The initial training and continuous hands-on coaching of midwives by TOTs contributed a lot to acquisition of the desired basic obstetric ultrasound screening skills. <b>Conclusion: </b>Women in developing countries are eager to access obstetric ultrasound screening services but for limited opportunities and sustainable implementation frameworks on Point of Care Ultrasound Screening (POCUS) services. Training and continuous coaching of frontline health professionals are critical in deployment of POCUS but there is limited access to standardised training content. 展开更多
关键词 Point of Care Ultrasonography Screening (POCUS) Midwives Antenatal Pri-mary Health Care Settings Business Model
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文章速递A Study of Caristi’s Fixed Point Theorem on Normed Space and Its Applications 认领
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作者 Md. Abdul Mannan Moqbul Hossain +1 位作者 Halima Akter Samiran Mondal 《理论数学进展(英文)》 2021年第3期169-179,共11页
In this work, we will discuss Caristi’s fixed point theorem for mapping results introduced in the setting of normed spaces. This work is a generalization of the classical Caristi’s fixed point theorem. Also, Caristi... In this work, we will discuss Caristi’s fixed point theorem for mapping results introduced in the setting of normed spaces. This work is a generalization of the classical Caristi’s fixed point theorem. Also, Caristi’s type of fixed points theorem was partial discussed in Reich, Mizoguchi and Takahashi’s and Amini-Harandi’s results, we developed ideas that many known fixed point theorems can easily be derived from the Caristi theorem. 展开更多
关键词 Norm Uniformity Mizoguchi and Takahashi’s Rich’s Problem Caristi’s Fixed Point Theorem Strong and Weak Contraction Semi-Continuous
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文章速递Uniqueness of Positive Radial Solutions for a Class of Semipositone Systems on the Exterior of a Ball 认领
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作者 Alhussein Mohamed Khalid Ahmed Abbakar +4 位作者 Abuzar Awad Omer Khalil Bechir Mahamat Acyl Abdoulaye Ali Youssouf Mohammed Mousa 《应用数学(英文)》 2021年第3期131-146,共16页
In this paper, we study the positive radial solutions for elliptic systems to the nonlinear BVP:<br /> <p> <img src="Edit_4da56369-d8f9-42d0-9650-c15af375d30c.bmp" alt="" />, whe... In this paper, we study the positive radial solutions for elliptic systems to the nonlinear BVP:<br /> <p> <img src="Edit_4da56369-d8f9-42d0-9650-c15af375d30c.bmp" alt="" />, where Δ<em>u</em> = <em>div</em> (<span style="white-space:nowrap;">&#8711;</span><em>u</em>) and Δ<em>v</em> = <em>div</em> (<span style="white-space:nowrap;">&#8711;</span><em>v</em>) are the Laplacian of <em>u</em>, <span style="white-space:nowrap;"><em>&#955;</em> </span>is a positive parameter, Ω = {<em>x</em> ∈ R<sup><em>n</em></sup> : <em>N</em> > 2, |<em>x</em>| > <em>r</em><sub>0</sub>, <em>r</em><sub>0</sub> > 0}, let <em>i</em> = [1,2] then <em>K<sub>i</sub></em> :[<em>r</em><sub>0</sub>,∞] → (0,∞) is a continuous function such that lim<sub><em>r</em>→∞</sub> <em>k<sub>i</sub></em>(<em>r</em>) = 0 and <img src="Edit_19f045da-988f-43e9-b1bc-6517f5734f9c.bmp" alt="" /> is The external natural derivative, and <img src="Edit_3b36ed6b-e780-46de-925e-e3cf7c6a125f.bmp" alt="" />: [0, ∞) → (0, ∞) is a continuous function. We discuss existence and multiplicity results for classes of <em>f </em>with a) <em>f<sub>i </sub></em>> 0, b) <em>f<sub>i </sub></em>< 0, and c) <em>f<sub>i </sub></em>= 0. We base our presence and multiple outcomes via the Sub-solutions method. We also discuss some unique findings. </p> 展开更多
关键词 Elliptic System Positive Radial Solution Exterior Domains Fixed Point Index
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文章速递Regeneration Characteristics and Spatial Pattern of <i>Platycladus orientalis</i>in Mount Tai, China 认领
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作者 Wenhui Li Xiyue Zhao +2 位作者 Jinli Bian Ruiqiang Liu Ruiqiang Ni 《生态学期刊(英文)》 2021年第3期276-286,共11页
<em>Platycladus orientalis</em> is one of the main tree species in Mount Tai, and its sustainable development is of great significance to the protection and development of the forest ecological environment... <em>Platycladus orientalis</em> is one of the main tree species in Mount Tai, and its sustainable development is of great significance to the protection and development of the forest ecological environment of Mount Tai. In this study, a representative sample plot of <em>Platycladus orientalis</em> with a size of 30 m * 20 m was selected on Mount Tai. The growth and distribution of the parent trees and seedlings of <em>Platycladus orientalis</em> were investigated in the sample plots. The results showed that both the mother cypress trees and seedlings inside the plot present an aggregated distribution pattern within a certain scale, which conforms to the distribution of most natural communities;and the mother cypress can promote seedlings within a certain scale. Although <em>Platycladus orientalis</em> has good natural regeneration ability, it is difficult to succeed in understory regeneration solely relying on natural fertility, and it is not conducive to the long-term stable development of forest stands. Therefore, the thinning of <em>Platycladus orientalis</em> and the adjustment of the forest stand structure and artificial promotion of natural regeneration can not only reduce operating costs, but also conform to the idea of forest near-natural management and maintain sustainable forest development. 展开更多
关键词 Platycladus orientalis Understory Regeneration Point Pattern Analysis Community Structure Intraspecific Relationship
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文章速递Depth Estimation from a Single Image Based on Cauchy Distribution Model 认领
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作者 Ying Ming 《电脑和通信(英文)》 2021年第3期133-142,共10页
Most approaches to estimate a scene’s 3D depth from a single image often model the point spread function (PSF) as a 2D Gaussian function. However, those method<span>s</span><span> are suffered ... Most approaches to estimate a scene’s 3D depth from a single image often model the point spread function (PSF) as a 2D Gaussian function. However, those method<span>s</span><span> are suffered from some noises, and difficult to get a high quality of depth recovery. We presented a simple yet effective approach to estimate exactly the amount of spatially varying defocus blur at edges, based on </span><span>a</span><span> Cauchy distribution model for the PSF. The raw image was re-blurred twice using two known Cauchy distribution kernels, and the defocus blur amount at edges could be derived from the gradient ratio between the two re-blurred images. By propagating the blur amount at edge locations to the entire image using the matting interpolation, a full depth map was then recovered. Experimental results on several real images demonstrated both feasibility and effectiveness of our method, being a non-Gaussian model for DSF, in providing a better estimation of the defocus map from a single un-calibrated defocused image. These results also showed that our method </span><span>was</span><span> robust to image noises, inaccurate edge location and interferences of neighboring edges. It could generate more accurate scene depth maps than the most of existing methods using a Gaussian based DSF model.</span> 展开更多
关键词 Depth Estimation Depth From Defocus Defocus Blur Gaussian Gradient Cauchy Distribution Point Spread Function (PSF)
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A FRACTIONAL NONLINEAR EVOLUTIONARY DELAY SYSTEM DRIVEN BY A HEMI-VARIATIONAL INEQUALITY IN BANACH SPACES 认领
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作者 翁云华 李雪松 黄南京 《数学物理学报:B辑英文版》 SCIE 2021年第1期187-206,共20页
This article deals with a new fractional nonlinear delay evolution system driven by a hemi-variational inequality in a Banach space.Utilizing the KKM theorem,a result concerned with the upper semicontinuity and measur... This article deals with a new fractional nonlinear delay evolution system driven by a hemi-variational inequality in a Banach space.Utilizing the KKM theorem,a result concerned with the upper semicontinuity and measurability of the solution set of a hemivariational inequality is established.By using a fixed point theorem for a condensing setvalued map,the nonemptiness and compactness of the set of mild solutions are also obtained for such a system under mild conditions.Finally,an example is presented to illustrate our main results. 展开更多
关键词 fractional differential variational inequality fractional nonlinear delay evolution equation hemi-variational inequality condensing map KKM theorem fixed point theorem
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COVID-19 and venous thromboembolism: Known and unknown for imaging decisions 认领
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作者 Love Patel Darshan Gandhi +3 位作者 Emily Westergard Michael Ornes Matthew Lillyblad Nedaa Skeik 《世界放射学杂志:英文版(电子版)》 2021年第3期64-74,共11页
As we continue to fight against the current coronavirus disease-2019(COVID-19)pandemic,healthcare professionals across the globe are trying to answer questions surrounding how to best help patients with the up-to-date... As we continue to fight against the current coronavirus disease-2019(COVID-19)pandemic,healthcare professionals across the globe are trying to answer questions surrounding how to best help patients with the up-to-date available science while awaiting the development of new therapies and mass vaccination.Since early in the pandemic,studies indicated a heightened risk of venous thromboembolism(VTE)in COVID-19 infected patients.There have been differing expert opinions about how to assess pretest probability of VTE in this patient population.This has been partly due to the high prevalence of respiratory failure in this patient population and the use of D-dimer as a prognostic test which is also frequently elevated in patients with COVID-19 in absence of VTE.Some experts have argued for an approach similar to usual care with testing if clinical suspicion is high enough.Some have argued for more routine screening at different points of care.Others have even suggested empiric therapeutic anticoagulation in moderate to severely ill COVID-19 patients.In the following article,we review and summarize the most current literature in hopes of assisting clinicians in decision making and guidance for when to be concerned for VTE in COVID-19 patients.We also discuss research gaps and share pathways currently being used within our institution. 展开更多
关键词 COVID-19 Venous thromboembolism Computed tomography scan ANTICOAGULATION Point of care ultrasound
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Detection of Multiscale Center Point Objects Based on Parallel Network 认领
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作者 Hao Chen Hong Zheng Xiaolong Li 《人工智能技术学报(英文)》 2021年第1期68-73,共6页
Anchor-based detectors are widely used in object detection.To improve the accuracy of object detection,multiple anchor boxes are intensively placed on the input image,yet.Most of which are invalid.Although the anchor-... Anchor-based detectors are widely used in object detection.To improve the accuracy of object detection,multiple anchor boxes are intensively placed on the input image,yet.Most of which are invalid.Although the anchor-free method can reduce the number of useless anchor boxes,the invalid ones still occupy a high proportion.On this basis,this paper proposes a multiscale center point object detection method based on parallel network to further reduce the number of useless anchor boxes.This study adopts the parallel network architecture of hourglass-104 and darknet-53 of which the first one outputs heatmaps to generate the center point for object feature location on the output attribute feature map of darknet-53.Combining feature pyramid and CIoU loss function,this algorithm is trained and tested on MSCOCO dataset,increasing the detection rate of target location and the accuracy rate of small object detection.Though resembling the state-of-the-art two-stage detectors in overall object detection accuracy,this algorithm is superior in speed. 展开更多
关键词 deep learning heatmap feature pyramid networks object detection center point
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Cold hardiness of the invasive fall armyworm,Spodoptera frugiperda in China 认领 被引量:2
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作者 ZHANG Dan-dan ZHAO Sheng-yuan +2 位作者 WU Qiu-lin LI Yu-yan WU Kong-ming 《农业科学学报:英文版》 SCIE CAS 2021年第3期764-771,共8页
Fall armyworm,Spodoptera frugiperda(J.E.Smith,1797),a crop pest native to tropical and subtropical regions of America,has invaded and spread into most regions in China,posing a severe threat to China’s agriculture.Th... Fall armyworm,Spodoptera frugiperda(J.E.Smith,1797),a crop pest native to tropical and subtropical regions of America,has invaded and spread into most regions in China,posing a severe threat to China’s agriculture.The cold hardiness directly determines its geographic distribution through adapting to winter temperatures of different regions.Here,we measured supercooling points and lethal time(LT)at low temperatures of S.frugiperda.The supercooling points for developmental stages in increasing order were:adults(-15.05℃)<pupae(-13.25℃)<prepupae(-10.50℃)<larvae(-9.03℃).Among eggs and 1st to 4th in star larvae,the 99%lethal time(LT_(99))was the highest for 4th in star larvae,with 99%of larvae dying after 18.59 d at 2℃,58.72 d at 7℃,and 66.28 d at 13℃.LT_(99) was the lowest for eggs with LTgg of 5.33 d at 2℃,9.28 d at 7℃,and 12.97 d at 13℃.This study provides mn understanding of overwintering regions of S.frugiperda in China which will be helpful for population forecasting and management. 展开更多
关键词 Spodoptera frugiperda supercooling point OVERWINTER China
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The entanglement properties of holographic QCD model with a critical end point 认领
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作者 李志镔 许坤严 黄梅 《中国物理C:英文版》 SCIE CAS 2021年第1期175-186,共12页
We investigated different entanglement properties of a holographic QCD(hQCD)model with a critical end point at the finite baryon density.Firstly,we considered the holographic entanglement entropy(HEE)of this hQCD mode... We investigated different entanglement properties of a holographic QCD(hQCD)model with a critical end point at the finite baryon density.Firstly,we considered the holographic entanglement entropy(HEE)of this hQCD model in a spherical shaped region and a strip shaped region.It was determined that the HEE of this hQCD model in both regions can reflect QCD phase transition.Moreover,although the area formulas and minimal area equations of the two regions were quite different,the HEE exhibited a similar behavior on the QCD phase diagram.Therefore,we assert that the behavior of the HEE on the QCD phase diagram is independent of the shape of the subregions.However,the HEE is not an ideal parameter for the characterization of the entanglement between different subregions of a thermal system.As such,we investigated the mutual information(MI),conditional mutual information(CMI),and the entanglement of purification(Ep)in different strip shaped regions.We determined that the three entanglement quantities exhibited some universal behavior;their values did not change significantly in the hadronic matter phase but increased rapidly with the increase in T andμin the QGP phase.Near the phase boundary,these three entanglement quantities changed smoothly in the crossover region and continuously but not smoothly at CEP;they exhibited discontinuous behavior in the first phase transition region.These properties can be used to distinguish between the different phases of strongly coupled matter. 展开更多
关键词 holographic QCD critical end point entanglement properties
Non-parametric machine learning methods for interpolation of spatially varying non-stationary and non-Gaussian geotechnical properties 认领
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作者 Chao Shi Yu Wang 《地学前缘:英文版》 SCIE CAS 2021年第1期339-350,共12页
Spatial interpolation has been frequently encountered in earth sciences and engineering.A reasonable appraisal of subsurface heterogeneity plays a significant role in planning,risk assessment and decision making for g... Spatial interpolation has been frequently encountered in earth sciences and engineering.A reasonable appraisal of subsurface heterogeneity plays a significant role in planning,risk assessment and decision making for geotechnical practice.Geostatistics is commonly used to interpolate spatially varying properties at un-sampled locations from scatter measurements.However,successful application of classic geostatistical models requires prior characterization of spatial auto-correlation structures,which poses a great challenge for unexperienced engineers,particularly when only limited measurements are available.Data-driven machine learning methods,such as radial basis function network(RBFN),require minimal human intervention and provide effective alternatives for spatial interpolation of non-stationary and non-Gaussian data,particularly when measurements are sparse.Conventional RBFN,however,is direction independent(i.e.isotropic)and cannot quantify prediction uncertainty in spatial interpolation.In this study,an ensemble RBFN method is proposed that not only allows geotechnical anisotropy to be properly incorporated,but also quantifies uncertainty in spatial interpolation.The proposed method is illustrated using numerical examples of cone penetration test(CPT)data,which involve interpolation of a 2D CPT cross-section from limited continuous 1D CPT soundings in the vertical direction.In addition,a comparative study is performed to benchmark the proposed ensemble RBFN with two other non-parametric data-driven approaches,namely,Multiple Point Statistics(MPS)and Bayesian Compressive Sensing(BCS).The results reveal that the proposed ensemble RBFN provides a better estimation of spatial patterns and associated prediction uncertainty at un-sampled locations when a reasonable amount of data is available as input.Moreover,the prediction accuracy of all the three methods improves as the number of measurements increases,and vice versa.It is also found that BCS prediction is less sensitive to the number of measurement data and ou 展开更多
关键词 Spatial interpolation Multiple point statistics Bayesian compressive sampling Compressive sensing Sparse measurement
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Individual Identification of Electronic Equipment Based on Electromagnetic Fingerprint Characteristics 认领
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作者 Han Xu Hongxin Zhang +3 位作者 Jun Xu Guangyuan Wang Yun Nie Hua Zhang 《中国通信:英文版》 SCIE 2021年第1期169-180,共12页
With the rapid development of communication and computer,the individual identification technology of communication equipment has been brought to many application scenarios.The identification of the same type of electr... With the rapid development of communication and computer,the individual identification technology of communication equipment has been brought to many application scenarios.The identification of the same type of electronic equipment is of considerable significance,whether it is the identification of friend or foe in military applications,identity determination,radio spectrum management in civil applications,equipment fault diagnosis,and so on.Because of the limited-expression ability of the traditional electromagnetic signal representation methods in the face of complex signals,a new method of individual identification of the same equipment of communication equipment based on deep learning is proposed.The contents of this paper include the following aspects:(1)Considering the shortcomings of deep learning in processing small sample data,this paper provides a universal and robust feature template for signal data.This paper constructs a relatively complete signal template library from multiple perspectives,such as time domain and transform domain features,combined with high-order statistical analysis.Based on the inspiration of the image texture feature,characteristics of amplitude histogram of signal and the signal amplitude co-occurrence matrix(SACM)are proposed in this paper.These signal features can be used as a signal fingerprint template for individual identification.(2)Considering the limitation of the recognition rate of a single classifier,using the integrated classifier has achieved better generalization ability.The final average accuracy of 5 NRF24LE1 modules is up to 98%and solved the problem of individual identification of the same equipment of communication equipment under the condition of the small sample,low signal-to-noise ratio. 展开更多
关键词 signal fingerprints histogram-based signal feature starting point detection signal level cooccurrence matrix ensemble Learningn
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Research advances in non-Darcy flow in low permeability media 认领
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作者 HAO Hong-bo LV Jie +2 位作者 CHEN Yan-mei WANG Chuan-zi HUANG Xiao-rui 《地下水科学与工程:英文版》 2021年第1期83-92,共10页
More and more experimental results show that Darcy’s law is not fully applicable in low permeability media,and non-Darcy flow has been identified.In this paper we reviewed the research of non-Darcy flow experiments i... More and more experimental results show that Darcy’s law is not fully applicable in low permeability media,and non-Darcy flow has been identified.In this paper we reviewed the research of non-Darcy flow experiments in low-permeability media in recent decades,discuss the existence of non-Darcy flow,and summarize its constitutive equations.The reasons for the threshold gradient were also discussed and summarized for the criterion of the critical point of non-Darcy flow.On this basis,the future development of non-Darcy flow experiments in the rock and clay media were discussed,in order to provide a certain reference for subsequent research on seepage laws in low permeability media. 展开更多
关键词 Low permeability media Non-Darcy flow Constitutive equation Critical point criterion
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