期刊文献+
共找到41,599篇文章
< 1 2 250 >
每页显示 20 50 100
Cosmology-Independent Photon Mass Limits from Localized Fast Radio Bursts by Using Artificial Neural Networks
1
作者 冉景遇 王宝 魏俊杰 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第5期177-183,共7页
A hypothetical photon mass m_(γ) can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed di... A hypothetical photon mass m_(γ) can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed distance. The dispersion measure and redshift measurements of fast radio bursts(FRBs) have been widely used to constrain the rest mass of the photon. However, all current studies analyzed the effect of the frequency-dependent dispersion for massive photons in the standard ΛCDM cosmological context. In order to alleviate the circularity problem induced by the presumption of a specific cosmological model based on the fundamental postulate of the masslessness of photons, here we employ a new model-independent smoothing technique, artificial neural network(ANN), to reconstruct the Hubble parameter H(z) function from 34 cosmic-chronometer measurements.By combining observations of 32 well-localized FRBs and the H(z) function reconstructed by ANN, we obtain an upper limit of m_(γ) ≤ 3.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 2.0 × 10^(-15)eV/c^(2)(m_(γ) ≤ 6.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 3.6 × 10^(-15)eV/c_(2)) at the 1σ(2σ) confidence level. This is the first cosmology-independent photon mass limit derived from extragalactic sources. 展开更多
关键词 DISPERSION LIMIT independent
下载PDF
Change in Functional Status from Preoperative to One Year Postoperative in Patients Who Have Undergone Elective Open-Heart Surgery: A Repeated-Measures Study
2
作者 A. Kate MacPhedran David Barker +1 位作者 Mark Marbey Kieran Fogarty 《World Journal of Cardiovascular Diseases》 CAS 2024年第6期421-433,共13页
Purpose: Although patient-related factors affect surgical outcomes, preoperative functional status is not measured by any cardiac risk score. Functional status can, however, be objectively measured using validated out... Purpose: Although patient-related factors affect surgical outcomes, preoperative functional status is not measured by any cardiac risk score. Functional status can, however, be objectively measured using validated outcome tools such as the Late-Life Function and Disability Instrument (LLFDI). The purpose of this study was to determine 1) if there was a change over time in functional status, as measured by the LLFDI, in patients who underwent elective cardiac surgery, and if so, 2) what specific aspect(s) of functional status changed. Methods: A prospective longitudinal study of one year was conducted on elective cardiac surgery patients (n = 43) using the self-reported LLFDI, which measures Disability Frequency (frequency of participation in social tasks), Disability Limitation (ability to participate in social tasks) and Function Total (ease in performing routine activities). Higher scores indicate increased function and decreased disability. LLFDI scores were compared at three times (preoperative, six-week and one-year postoperative) using repeated measures ANOVA. Post hoc pairwise comparison was conducted for specific interactions. Results: Both Function Total and Disability Frequency significantly changed over time (p = 0.047 and p = 0.013, respectively). Specifically, patients’ function level was significantly higher one-year postoperative compared to preoperative (M difference = +3.48, SE = 1.48, p = 0.026). Likewise, Disability Frequency scores were significantly higher (i.e. more active) at one-year postoperative versus preoperative (M difference= +5.98, SE = 2.19, p = 0.033). Disability Limitation scores were not significantly different between any time points (p > 0.05). Conclusion: By one-year postoperative, patients demonstrated increased ease in their routine physical activities and were more participatory in social life tasks. Individuals who underwent elective cardiac surgery took more than six weeks to detect notable improvement in functional status, which was expected with a sternotomy approach. This study provides support for the use of the LLFDI as an effective tool to capture functional status in the cardiac population. These findings may assist cardiac patients in recovery timeline expectations. 展开更多
关键词 Functional Status elective Cardiac Surgery Late-Life Function and Disability Instrument
下载PDF
Reasons for Elective Surgery Cancellations in a Senegalese Pediatric Surgery Department
3
作者 Cheikh Tidiane Mbaye Cheikh Diouf +8 位作者 Florent Tshibwid A Zeng Faty Balla Lô Lissoune Cissé Doudou Gueye Ibrahima Bocar Wellé Souleymane Camara Papa Alassane Mbaye Oumar Ndour Gabriel Ngom 《Open Journal of Pediatrics》 2024年第5期783-789,共7页
Introduction: Cancellation of elective surgery is common in developing countries. This decision is difficult to make as it generates economic and organizational consequences for the healthcare facility and an addition... Introduction: Cancellation of elective surgery is common in developing countries. This decision is difficult to make as it generates economic and organizational consequences for the healthcare facility and an additional source of stress for patients and their caregivers. This study aimed to analyze the various aspects of this medical problem. Patients and Methods: We conducted a prospective and descriptive study over six months (from January 1st, 2017, to June 30th, 2017) at the pediatric surgery department of Aristide Le Dantec University Teaching Hospital in Senegal. Results: Ninety-one cases were collected. The cancellation rate was 20.8%. Infants were affected in 36.3% of cases. Among anesthesiologists, 83.5% were residents, and 16.5% were specialists. Cancellation in nephroblastoma children with an indication for extended nephrectomy represented 15.4% of cases. Concerning reasons for cancellation, comorbidities, dominated by respiratory infections, accounted for 28.5% of cases, patient absences for 24.2%, and issues related to the anesthesiologist for 17.6%. Cancellations were avoidable in 33% of cases. Patients were responsible for cancellation in 37.4% of cases, the healthcare system in 33%, and medical reasons in 29.7%. Conclusion: Our findings suggest that one-third of cancellations could have been avoided with improvements in the healthcare system. Actions should be taken to reduce the cancellation rate in our context. 展开更多
关键词 CANCELLATION elective Surgery Pediatric Surgery LMICs Senegal
下载PDF
A Constrained Local Neighborhood Approach for Efficient Markov Blanket Discovery in Undirected Independent Graphs
4
作者 Kun Liu Peiran Li +4 位作者 Yu Zhang JiaRen Ming Li Xianyu Wang Cong Li 《Computers, Materials & Continua》 SCIE EI 2024年第8期2535-2555,共21页
When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm efficiency.Traditional constr... When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm efficiency.Traditional constraint-based methods typically rely on the results of conditional independence tests.However,excessive reliance on these test results can lead to a series of problems,including increased computational complexity and inaccurate results,especially when dealing with large-scale networks where performance bottlenecks are particularly evident.To overcome these challenges,we propose a Markov blanket discovery algorithm based on constrained local neighborhoods for constructing undirected independence graphs.This method uses the Markov blanket discovery algorithm to refine the constraints in the initial search space,sets an appropriate constraint radius,thereby reducing the initial computational cost of the algorithm and effectively narrowing the initial solution range.Specifically,the method first determines the local neighborhood space to limit the search range,thereby reducing the number of possible graph structures that need to be considered.This process not only improves the accuracy of the search space constraints but also significantly reduces the number of conditional independence tests.By performing conditional independence tests within the local neighborhood of each node,the method avoids comprehensive tests across the entire network,greatly reducing computational complexity.At the same time,the setting of the constraint radius further improves computational efficiency while ensuring accuracy.Compared to other algorithms,this method can quickly and efficiently construct undirected independence graphs while maintaining high accuracy.Experimental simulation results show that,this method has significant advantages in obtaining the structure of undirected independence graphs,not only maintaining an accuracy of over 96%but also reducing the number of conditional independence tests by at least 50%.This significant performance improvement is due to the effective constraint on the search space and the fine control of computational costs. 展开更多
关键词 Bayesian network structure learning Markov blanket conditional independence
下载PDF
Origin of the Dashuigou independent tellurium deposit at Qinghai–Xizang Plateau: constraints from the light stable isotopes C, O, and H
5
作者 Jianzhao Yin Yuhong Chao +2 位作者 Haoyu Yin Hongyun Shi Shoupu Xiang 《Acta Geochimica》 EI CAS CSCD 2024年第2期385-398,共14页
By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)... By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)O and δ^(13)C isotope signatures of dolomite samples vary between 10.2 and 13.0‰,and between−7.2 and−5.2‰,respectively,implying that the carbon derives from the upper mantle.δD and δ^(18) O of quartz,biotite,and muscovite from diff erent ore veins of the deposit vary between−82 and−59‰,and between 11.6 and 12.4‰,respectively,implying that the metallogenic solutions are mainly magmatic.According to the relevant research results of many isotope geologists,the fractionation degree of hydrogen isotopes increases as the depth to the Earth’s core increases,and the more diff erentiated the hydrogen isotopes are,the lower their values will be.In other words,mantle-derived solutions can have extremely low hydrogen isotope values.This means that the δD‰ value−134 of the pyrrhotite sample numbered SD-34 in this article may indicate mantle-derived oreforming fl uid of the deposit.The formation of the Dashuigou tellurium deposit occurred between 91.71 and 80.19 Ma. 展开更多
关键词 Carbon oxygen and hydrogen isotopes ORIGIN independent tellurium deposit The Qinghai–Xizang Plateau
下载PDF
Are cities greener because of innovation?Independent innovation policy and green economic efficiency
6
作者 Zhuoji Zheng Xueqin Li +3 位作者 Mengjie Yu Yuan Li Xianfeng Han Yuping Yin 《Chinese Journal of Population,Resources and Environment》 2024年第2期118-126,共9页
The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278... The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278 prefecture-level cities in China from 2006 to 2020 and empirically examines the effect and internal mechanism of the NIIDZ on green economic efficiency(GEE)using the difference-in-difference model(DID).The results show that the NIIDZ effectively enhances the growth of GEE,and the results remain valid through several robustness tests,such as year-by-year propensity score matching.The transmission mechanism suggests that the NIIDZ indirectly drives GEE by accelerating scientific and technological investment,promoting talent concentration,and optimizing the industrial structure.Moreover,heterogeneity analysis reveals that the promotion effect of the NIIDZ on GEE is more prominent in the eastern region and high green development level areas.The study’s findings can serve as a reference for China to further utilize the policy effectiveness of the NIIDZ and accelerate the high-quality development of the green economy in the future. 展开更多
关键词 National innovation independent demonstration Zone(NIIDZ) Green economy efficiency(GEE) Difference-in-difference model(DID)
下载PDF
MPC-based Torque Distribution for Planar Motion of Four-wheel Independently Driven Electric Vehicles:Considering Motor Models and Iron Losses 被引量:3
7
作者 Yiyan Su Deliang Liang Peng Kou 《CES Transactions on Electrical Machines and Systems》 CSCD 2023年第1期45-53,共9页
The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly d... The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly distributing torques to minimize the power consumption,the driving range of 4WID-EV can be effectively improved.This paper proposes a model predictive control(MPC)-based torque distribution scheme,which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar motions.By incorporating the motor model considering iron losses,the optimal torque distribution can be achieved without an additional torque controller.Also,for this reason,the proposed control scheme is computationally efficient,since the power consumption term to be optimized,which is expressed as the product of the motor voltages and currents,is much simpler than that derived from the efficiency map.With reasonable simplification and linearization,the MPC problem is converted to a quadratic programming problem,which can be solved efficiently.The simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance. 展开更多
关键词 four-wheel independently driven electric vehicles Model predictive control Motor models Iron losses
下载PDF
Operational Problems and Countermeasures of Public Elective Courses in Higher Vocational Colleges and Universities Based on the Perspective of Academic Affairs Management:Taking Guangdong C Vocational College as an Example
8
作者 Jingjie Li 《Journal of Contemporary Educational Research》 2024年第9期277-282,共6页
With the vigorous development of higher vocational education,public elective courses,as one of the core components of the higher vocational curriculum system,occupy a pivotal position.Based on the perspective of acade... With the vigorous development of higher vocational education,public elective courses,as one of the core components of the higher vocational curriculum system,occupy a pivotal position.Based on the perspective of academic affairs management and taking Guangdong C Vocational College as an example,this paper meticulously analyzes the operational problems in the declaration,setting,teaching,and management of public elective courses through questionnaire surveys and other methods.It also puts forward a series of targeted solutions,with a view to continuously improving the teaching quality and management level of public elective courses. 展开更多
关键词 Academic affairs management Public elective courses Operational problems COUNTERMEASURES Higher vocational colleges and universities
下载PDF
Study on Independent Supervision Function of Design Assurance System
9
作者 SUI Lijun MA Congyao WANG Jianyuan 《International Journal of Plant Engineering and Management》 2024年第3期185-192,共8页
The effective operation of a design assurance system cannot be achieved without the effective performance of the independent supervision function.As one of the core functions of the design assurance system,the purpose... The effective operation of a design assurance system cannot be achieved without the effective performance of the independent supervision function.As one of the core functions of the design assurance system,the purpose of the independent supervision function is to ensure that the system operates within the scope of procedures and manuals.At present,the function of independent supervision is a difficult and confusing issue for various original equipment manufacturers as well as suppliers,and there is an urgent requirement to put forward relevant requirements and form relevant methods.Based on the above mentioned objective,the basic requirements of the independent supervision function of design assurance system were studied,the problems and deficiencies in the organization,staffing,and methods existing in the current independent supervision function were analyzed,the improvement suggestions and measures for the performance of the independent supervision function from the aspects of the organization,staffing,procedures,and suppliers were put forward.The present work and conclusions provide guidance and direction for the effective operation of the design assurance system. 展开更多
关键词 design of assurance systems independent supervision functions system operation internal audits SUPPLIERS
下载PDF
Analysis of the Role of Problem-Based Independent Learning Model in Teaching Cerebral Ischemic Stroke First Aid in Emergency Medicine
10
作者 Hua Liu 《Journal of Contemporary Educational Research》 2024年第6期16-21,共6页
Objective:To analyze the effect of using a problem-based(PBL)independent learning model in teaching cerebral ischemic stroke(CIS)first aid in emergency medicine.Methods:90 interns in the emergency department of our ho... Objective:To analyze the effect of using a problem-based(PBL)independent learning model in teaching cerebral ischemic stroke(CIS)first aid in emergency medicine.Methods:90 interns in the emergency department of our hospital from May 2022 to May 2023 were selected for the study.They were divided into Group A(45,conventional teaching method)and Group B(45 cases,PBL independent learning model)by randomized numerical table method to compare the effects of the two groups.Results:The teaching effect indicators and student satisfaction scores in Group B were higher than those in Group A(P<0.05).Conclusion:The use of the PBL independent learning model in the teaching of CIS first aid can significantly improve the teaching effect and student satisfaction. 展开更多
关键词 Problem-based independent learning model Emergency medicine Ischemic stroke First aid teaching SATISFACTION
下载PDF
Factors influencing the surveillance of re-emerging intracranial infections in elective neurosurgical patients:A single-center retrospective study 被引量:1
11
作者 Jiang-Long Wang Xi-Wen Wu +4 位作者 Sheng-Nan Wang Xuan Liu Bing Xiao Yu Wang Jing Yu 《World Journal of Clinical Cases》 SCIE 2023年第28期6680-6687,共8页
BACKGROUND At present,many studies have reported the risk factors for postoperative intracranial reinfection,including age,sex,time to surgery,duration of postoperative catheterization,emergency procedures,type of dis... BACKGROUND At present,many studies have reported the risk factors for postoperative intracranial reinfection,including age,sex,time to surgery,duration of postoperative catheterization,emergency procedures,type of disease and cerebrospinal fluid leakage,but the academic community has not reached a unified conclusion.AIM To find factors influencing the surveillance of re-emerging intracranial infections in elective neurosurgical patients.METHODS Ninety-four patients who underwent elective craniotomy from January 1,2015 to December 31,2022 in the Department of Neurosurgery,First Hospital of Jilin University,were included in this study.Of those,45 patients were enrolled in the infection group,and 49 were enrolled in the control group.The clinical data of the patients were collected and divided into three categories,including preoperative baseline conditions,intraoperative characteristics and postoperative infection prevention.The data were analyzed using SPSS 26.0 software.RESULTS There were 23 males and 22 females in the infection group with a mean age of 52.8±15.1 years and 17 males and 32 females in the control group with a mean age of 48.9±15.2 years.The univariate analysis showed that the infection group had higher systolic blood pressures and postoperative temperatures,fewer patients who underwent a supratentorial craniotomy,more patients with a history of hypertension and higher initial postoperative white blood cell counts than the control group,with statistically significant differences(P<0.05).The multifactorial logistic regression analysis showed that a history of hypertension and a high postoperative body temperature were independent risk factors for postoperative infection in neurosurgical patients.CONCLUSION The results obtained in this study indicated that a history of hypertension and a high postoperative body temperature were independent risk factors for postoperative neurological symptoms. 展开更多
关键词 Re-emerging infections Risk factors NEUROSURGERY elective surgery Intracranial infections
下载PDF
Frequency selective surface with better polarization independency for arbitrary incident angle 被引量:2
12
作者 贾宏燕 高劲松 冯晓国 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第3期1227-1230,共4页
This paper investigates the frequency-selective property of a planar layer consisting of period arrays both theoretically and experimentally for different polarizations at arbitrary incident angle. The novel element i... This paper investigates the frequency-selective property of a planar layer consisting of period arrays both theoretically and experimentally for different polarizations at arbitrary incident angle. The novel element is designed by loading the rectangular microstrip element with L-shaped conducting patch at its two ends. Based on the spectral-domain method, the frequency response including angle effect and polarization effect of the frequency selective surface (FSS) structure are analysed and the plots of the frequency versus transmission coefficient are obtained. As a result of the numerical analysis, it is shown that if the source polarization is changed, polarization-independence of previous FSS design can be achieved only for normal incidence, which limits most FSS applications. But in our proposed structure, the better polarization-independency for arbitrary incident angle can be achieved. It is observed that the simulated result comes very close to the experimental result. 展开更多
关键词 frequency selective surface (FSS) arbitrary incident angle polarization independency
下载PDF
Effect of Intravenous Tranexamic Acid in Reducing Blood Loss during and after Elective Caesarean Section in a Third Level Health Institution: A Randomized Controlled Study
13
作者 Darlington Omawumi Emmanuel Oranu +2 位作者 Rosemary Ogu Ngozi Orazulike Job Otokwala 《Open Journal of Obstetrics and Gynecology》 CAS 2023年第2期265-279,共15页
Background: Blood loss during caesarean section (C/S) may lead to postpartum haemorrhage, and is one of the direct causes of maternal mortality and morbidity globally. Tranexamic acid is recommended in the treatment o... Background: Blood loss during caesarean section (C/S) may lead to postpartum haemorrhage, and is one of the direct causes of maternal mortality and morbidity globally. Tranexamic acid is recommended in the treatment of postpartum haemorrhage (PPH) if oxytocin and other utertonics are ineffective in controlling PPH. In this centre it is not used prophylactically to reduce blood during caesarean section. Aim: To assess the effect of prophylactic intravenous tranexamic acid on blood loss during and after elective C/S at the University of Port Harcourt Teaching Hospital (UPTH). Methods: This was a prospective, single-blind, randomized, placebo-controlled interventional study conducted at the Obstetric theatre of UPTH from July 2020 to March 2021. Eligible women were randomized into two groups;seventy-two women received intravenous tranexamic acid while seventy-one women received a placebo. Socio-demographic data and the result of the study were collected through a proforma. Data collected was analyzed using Statistical Package for Social Sciences (SPSS) Version 22.0. The results were expressed in tables and charts as frequencies, percentages and mean. Chi-square test, Fisher’s exact, and T-test were used to determine the relationship between variables. P-value ≤ 0.05 was considered statistically significant. Results: The findings showed that tranexamic acid significantly reduced mean blood loss during and after C/S (p-value post-surgery was significantly lower in the tranexamic acid group (624.88 ± 200.76 ml) in comparison to the placebo group (864.24 ± 229.09 ml), p-value = 0.001. The mean post-C/S packed cell volume (PCV) was significantly higher among the tranexamic acid group (30.68% ± 2.80%) in comparison to the placebo group (28.07% ± 3.27%), t = 5.131, p-value = 0.0001. The maternal side effects were nausea and vomiting, 9 (12.5%) and 1 (1.4%) participants respectively. Conclusion: Tranexamic acid significantly reduced blood loss during and after elective C/S. Maternal side effects were less with tranexamic acid use. 展开更多
关键词 Tranexemic Acid Blood Loss elective Caesarean Section Port Harcourt
下载PDF
Prevalence of Pre-Operative Anxiety and Predictors among Elective Surgical Patients and Their Pre-Operative Hemodynamic Changes at Muhimbili National Hospital
14
作者 Rukia Abdul-Ghany Himid Msoma Ramadhani H. Khamis +3 位作者 Laurean P. Rwanyuma Larry O. Akoko Araika-Zawadhafsa Mkulo Peter Msinde 《Open Journal of Medical Psychology》 2023年第2期55-70,共16页
Background: Surgery is a traumatic process that may subject patients to physiological and psychological responses leading to pre and post-operative effects. Preoperative anxiety, if severe may be associated with sever... Background: Surgery is a traumatic process that may subject patients to physiological and psychological responses leading to pre and post-operative effects. Preoperative anxiety, if severe may be associated with several complications including cancellation of surgery, poor intra- and post-operative analgesic control, altered post-operative healing, and longer hospital stays to mention a few. Objective: The main purpose was to determine the prevalence and predictors of pre-operative anxiety among elective surgical patients and their hemodynamic changes in these patients in the Surgical department in MNH. Methodology: This was a prospective descriptive and analytical study performed at MNH which involved patients admitted for elective surgical procedures from June 2021 to February 2022. Information was gathered in a structured questionnaire along with APAIS scores. Results: 169 patients for elective surgery in General Surgery and Urology units were included in the study. Among them, 94 males and 74 females. The overall pre-operative anxiety was 11.8%, 80.5% had moderate to severe Information-Related anxiety, while 26% and 17.2% had moderate-to-severe surgery-related and anesthesia-related types of anxiety respectively. Conclusion: Pre-operative anxiety was comparatively lower in our settings as well no factor was found with a significant relation to pre-operative anxiety, hence further and broader evaluation is recommended to result in the assessment and management of patients before elective surgery. 展开更多
关键词 ANXIETY elective Surgery PREDICTORS APAIS
下载PDF
Solving the k-Independent Sets Problem of Graphs by Gröbner Bases
15
作者 Junyu Luo Shengzhen Ding 《Open Journal of Discrete Mathematics》 2023年第3期86-94,共9页
The aim of this paper is to given an algebraic computational method for finding maximal independent sets as well as the independent number of an arbitrary finite graph of n vertices G by strengthening the problem of f... The aim of this paper is to given an algebraic computational method for finding maximal independent sets as well as the independent number of an arbitrary finite graph of n vertices G by strengthening the problem of finding maximal independent sets of G to the problem of finding k-independent sets in G for. It is shown that the existence of k-independent sets in G is equivalent to the existence of solutions of a system of multivariate polynomial equations. It follows that the problem of finding k-independent sets can be realized by using Gröbner bases of polynomial ideals. Since the number of k-independent sets is finite, the triangular equations composed by Gröbner bases are easier to be solved. Consequently, the maximal independent sets and the independent number of G are obtained after solving at most n such equations. Finally, the numerical example is presented to illustrate the effectiveness of this algebraic computational method. 展开更多
关键词 k-independent Set Maximal independent Set Gröbner Bases
下载PDF
Prevalence of Preoperative Anemia in Elective Rheumatic Valve Surgery at a Tertiary Care Center in Nepal
16
作者 Priska Bastola Bibhush Shrestha +3 位作者 Bishwas Pradhan Arjun Gurung Basanta Ghimire Anil Bhattarai 《World Journal of Cardiovascular Surgery》 2023年第1期1-9,共9页
Background: Rheumatic Valvular Heart disease (RVHD) is common in developing countries often associated with anemia;however its burden is often overlooked. Anemic patients undergoing surgery are likely to receive blood... Background: Rheumatic Valvular Heart disease (RVHD) is common in developing countries often associated with anemia;however its burden is often overlooked. Anemic patients undergoing surgery are likely to receive blood transfusion, increasing morbidity and mortality. Prevalence of anemia in cardiac surgical patients are studied extensively, however its burden in RVHD is lacking. This study attempted to investigate the prevalence of preoperative anemia in RVHD and its effect on blood transfusion, morbidity and mortality in patients undergoing valve surgery. Methods: This is a retrospective observational study conducted at a tertiary care hospital in Nepal. We considered 340 patients who underwent Rheumatic valve replacement surgery from 2014 January to December 2016 and data on their socio-demographic and clinical characteristics were extracted from the patient’s records. The analyses meeting the study objectives were conducted using IBM SPSS v25 for Windows (IBM Statistical Package for Social Sciences, 2015IBM Corporation, New York, United States). Results: The prevalence of no anemia, mild, moderate, and severe anemia was 34.1%, 57.7%, 39.6%, 2.5%, respectively. The units of Red Blood Cell used for transfusion were 1.2 units, 2.0 units, 2.3 units, and 1.6 units in patients without anemia, and those with mild, moderate and severe anemia respectively. The incidence of reexploration was higher in patients with severe anemia as compared to the non anemic with an incidence of 66.6%. A proportion of the patients with no anemia, mild, moderate and severe anemia with less than 7 days stay in the intensive care unit were 89%, 82%, 84.7% and 100% respectively. The length of hospital stay more than 10 days was seen in 58.9%, 71.6%, 63% and 100% in patients with no anemia, mild, moderate and severe anemia. An overall incidence of mortality in anemic patients was 11% while in non anemic patients was 5.3%. Conclusions: The prevalence of anemia was high in the Nepalese patients with Rheumatic valvular heart disease planned for elective surgery. There was an increased incidence of blood transfusion, longer hospital stay, and increased mortality in anemic patients compared to their non anemic counterparts. 展开更多
关键词 ANEMIA Rheumatic Heart Disease elective Valve Surgery Blood Transfusion
下载PDF
Projecting Wintertime Newly Formed Arctic Sea Ice through Weighting CMIP6 Model Performance and Independence 被引量:1
17
作者 Jiazhen ZHAO Shengping HE +2 位作者 Ke FAN Huijun WANG Fei LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第8期1465-1482,共18页
Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Ar... Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Arctic multiyear sea ice,changes in newly formed sea ice indicate more thermodynamic and dynamic information on Arctic atmosphere–ocean–ice interaction and northern mid–high latitude atmospheric teleconnections. Here, we use a large multimodel ensemble from phase 6 of the Coupled Model Intercomparison Project(CMIP6) to investigate future changes in wintertime newly formed Arctic sea ice. The commonly used model-democracy approach that gives equal weight to each model essentially assumes that all models are independent and equally plausible, which contradicts with the fact that there are large interdependencies in the ensemble and discrepancies in models' performances in reproducing observations. Therefore, instead of using the arithmetic mean of well-performing models or all available models for projections like in previous studies, we employ a newly developed model weighting scheme that weights all models in the ensemble with consideration of their performance and independence to provide more reliable projections. Model democracy leads to evident bias and large intermodel spread in CMIP6 projections of newly formed Arctic sea ice. However, we show that both the bias and the intermodel spread can be effectively reduced by the weighting scheme. Projections from the weighted models indicate that wintertime newly formed Arctic sea ice is likely to increase dramatically until the middle of this century regardless of the emissions scenario.Thereafter, it may decrease(or remain stable) if the Arctic warming crosses a threshold(or is extensively constrained). 展开更多
关键词 wintertime newly formed Arctic sea ice model democracy model weighting scheme model performance model independence
下载PDF
Timing of Elective Repeat Cesarean Delivery at 38 Weeks versus 39 Weeks: Rate of Spontaneous Onset of Labor before Planned Cesarean Section and Impact on Maternal Outcome: A Retrospective Cohort Study
18
作者 Amal Radi Al Somairi Wafa Abdulaziz Bedaiwi Yaser Abdulkarim Faden 《Open Journal of Obstetrics and Gynecology》 2023年第3期550-565,共16页
Background: The timing of elective repeat cesarean delivery at 38 weeks versus 39 weeks is still a debatable subject, both regarding maternal and neonatal outcomes. In the Saudi context, there is lack of local data to... Background: The timing of elective repeat cesarean delivery at 38 weeks versus 39 weeks is still a debatable subject, both regarding maternal and neonatal outcomes. In the Saudi context, there is lack of local data to aid decision-making regarding the timing of elective repeat cesarean delivery. Objectives: To estimate the rate of spontaneous onset of labor before the planned gestational age for repeat cesarean section in women who were booked at gestational age of (39 0/7 - 39 6/7) weeks (W39) versus (38 0/7 - 38 6/7) weeks (W38) and to compare the rate of maternal composite outcome between these groups. Design: Retrospective cohort. Setting: This study was conducted at King Abdulaziz Medical City, Jeddah, KSA. Method: Delivery registry books were reviewed to identify all deliveries from 1 January 2014 to 31 December 2016 (3 years). All low-risk pregnant women who had 2 or more cesarean deliveries and who met the inclusion criteria were included. Results: A total of 440 women were included of whom 318 (72.3%) were planned for elective cesarean section at W38 gestational age and 122 women at W39 gestational age. Mothers planned at W39 had higher rate of emergency cesarean deliveries versus those planned at W38 (18.0% versus 10.4%, p = 0.030;RR = 13.06), most frequently due to early onset of contractions (16.4% versus 8.2%, p = 0.012;RR = 12.17) or cervical dilatation (11.6% versus 5.4%, p = 0.024, RR = 16.15). No difference in the incidence of individual or composite maternal complications was noted between the two groups. Mother’s age (OR 0.93, p = 0.018) and schedule date at W39 (OR = 1.94, p = 0.028) were independently associated with spontaneous onset of labor before the scheduled gestational age, while no association was found with parity, previous number of spontaneous vaginal deliveries, number of previous cesarean deliveries or interval from last cesarean delivery. Conclusion: Elective cesarean section scheduled at 39 weeks of gestation or beyond carries a higher risk of emergency cesarean section, with no significant increase in maternal complications. The identification of factors associated with spontaneous onset of labor before the planned gestational age should be carefully identified to determine the optimal timing. 展开更多
关键词 elective Cesarean Emergency Cesarean Repeat Cesarean Previous Cesarean Spontaneous Onset of Labor Maternal Outcome Neonatal Outcome Timing of Delivery Risk Factors
下载PDF
Functional magnetic resonance imaging study of group independent components underpinning item responses to paranoid-depressive scale
19
作者 Drozdstoy Stoyanov Rositsa Paunova +3 位作者 Julian Dichev Sevdalina Kandilarova Vladimir Khorev Semen Kurkin 《World Journal of Clinical Cases》 SCIE 2023年第36期8458-8474,共17页
BACKGROUND Our study expand upon a large body of evidence in the field of neuropsychiatric imaging with cognitive,affective and behavioral tasks,adapted for the functional magnetic resonance imaging(MRI)(fMRI)experime... BACKGROUND Our study expand upon a large body of evidence in the field of neuropsychiatric imaging with cognitive,affective and behavioral tasks,adapted for the functional magnetic resonance imaging(MRI)(fMRI)experimental environment.There is sufficient evidence that common networks underpin activations in task-based fMRI across different mental disorders.AIM To investigate whether there exist specific neural circuits which underpin differ-ential item responses to depressive,paranoid and neutral items(DN)in patients respectively with schizophrenia(SCZ)and major depressive disorder(MDD).METHODS 60 patients were recruited with SCZ and MDD.All patients have been scanned on 3T magnetic resonance tomography platform with functional MRI paradigm,comprised of block design,including blocks with items from diagnostic paranoid(DP),depression specific(DS)and DN from general interest scale.We performed a two-sample t-test between the two groups-SCZ patients and depressive patients.Our purpose was to observe different brain networks which were activated during a specific condition of the task,respectively DS,DP,DN.RESULTS Several significant results are demonstrated in the comparison between SCZ and depressive groups while performing this task.We identified one component that is task-related and independent of condition(shared between all three conditions),composed by regions within the temporal(right superior and middle temporal gyri),frontal(left middle and inferior frontal gyri)and limbic/salience system(right anterior insula).Another com-ponent is related to both diagnostic specific conditions(DS and DP)e.g.It is shared between DEP and SCZ,and includes frontal motor/language and parietal areas.One specific component is modulated preferentially by to the DP condition,and is related mainly to prefrontal regions,whereas other two components are significantly modulated with the DS condition and include clusters within the default mode network such as posterior cingulate and precuneus,several occipital areas,including lingual and fusiform gyrus,as well as parahippocampal gyrus.Finally,component 12 appeared to be unique for the neutral condition.In addition,there have been determined circuits across components,which are either common,or distinct in the preferential processing of the sub-scales of the task.CONCLUSION This study has delivers further evidence in support of the model of trans-disciplinary cross-validation in psychiatry. 展开更多
关键词 Paranoid-depressive scale Functional magnetic resonance imaging Cross-validation Group independent component analysis Schizophrenia Depression
下载PDF
The Effect of Early versus Traditional Hospital Discharge on Activities of Daily Living for Women Undergoing Elective Cesarean Section. An Observational Cohort Study
20
作者 Ahmed Mohammed Elmaraghy Rasha Elhoseny Yehia Ahmed Hamdy Naguib 《Open Journal of Obstetrics and Gynecology》 2023年第3期642-653,共12页
Background: Cesarean section is one of the most common surgeries performed worldwide and its consequences and complications represent a major public health concern. The policy of enhanced recovery after surgery has be... Background: Cesarean section is one of the most common surgeries performed worldwide and its consequences and complications represent a major public health concern. The policy of enhanced recovery after surgery has been implemented after cesarean section to optimize perioperative care. Enhanced recovery also aims to reduce the length of hospital stay, which might imply substantial healthcare savings. Rising hospital costs are one of the factors in early discharge. Patients & Methods: This was a prospective cohort study. 158 patients met the inclusion criteria of the study, 81 patients were discharged after 48 hours and 77 patients were discharged after 24 hours. All patients received the same postoperative care and instructions. All the study participants received a phone call 1, 3, and 5 days after discharge to objectively assess the activities of daily living through Katz index of independence in activities of daily living. All patients were offered a postpartum visit 1 week after discharge during which the wound was assessed by the Southampton wound assessment scale. Moreover, other maternal complications such as mastitis, puerperal sepsis, or pyelonephritis were assessed and cases who were readmitted were documented. Initiation of successful breastfeeding and neonatal readmission were reported as well. Results: 158 patients met the inclusion/exclusion criteria of the study. There was no significant difference between the two arms of the study regarding baseline characteristics. Katz index of independence showed that the resumption of activities of daily living after CS was similar in both arms of the study on days 1, 3 and 5 after discharge. Time till the passage of flatus and stool after the cesarean section was significantly shorter among the early discharge arm (9.31 VS 14.68, p value < 0.001 & 13.25 VS 24.82, p value < 0.001 respectively). Maternal readmission was not significantly higher among the early discharge arm and at the 1-week postpartum visit, objective wound assessment by Southampton wound scoring assessment was made and there was no significant difference between the two arms of the study. Initiation of successful breastfeeding, and neonatal readmission were similar in both groups. Conclusion: The policy of early discharge can be adopted in low-risk cases scheduled for elective uncomplicated CS provided that the mother and the neonate are in good general condition and proper instructions regarding red flag manifestations are given. 展开更多
关键词 Cesarean Section Early Discharge Katz Index of independence in Activities of Daily Living
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部