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Pulse oximetry in pediatric care:Balancing advantages and limitations
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作者 Mohammed Al-Beltagi Nermin Kamal Saeed +1 位作者 Adel Salah Bediwy Reem Elbeltagi 《World Journal of Clinical Pediatrics》 2024年第3期69-97,共29页
BACKGROUND Pulse oximetry has become a cornerstone technology in healthcare,providing non-invasive monitoring of oxygen saturation levels and pulse rate.Despite its widespread use,the technology has inherent limitatio... BACKGROUND Pulse oximetry has become a cornerstone technology in healthcare,providing non-invasive monitoring of oxygen saturation levels and pulse rate.Despite its widespread use,the technology has inherent limitations and challenges that must be addressed to ensure accurate and reliable patient care.AIM To comprehensively evaluate the advantages,limitations,and challenges of pulse oximetry in clinical practice,as well as to propose recommendations for optimizing its use.METHODS A systematic literature review was conducted to identify studies related to pulse oximetry and its applications in various clinical settings.Relevant articles were selected based on predefined inclusion and exclusion criteria,and data were synthesized to provide a comprehensive overview of the topic.RESULTS Pulse oximetry offers numerous advantages,including non-invasiveness,real-time feedback,portability,and costeffectiveness.However,several limitations and challenges were identified,including motion artifacts,poor peripheral perfusion,ambient light interference,and patient-specific factors such as skin pigmentation and hemoglobin variants.Recommendations for optimizing pulse oximetry use include technological advancements,education and training initiatives,quality assurance protocols,and interdisciplinary collaboration.CONCLUSION Pulse oximetry is crucial in modern healthcare,offering invaluable insights into patients’oxygenation status.Despite its limitations,pulse oximetry remains an indispensable tool for monitoring patients in diverse clinical settings.By implementing the recommendations outlined in this review,healthcare providers can enhance the effectiveness,accessibility,and safety of pulse oximetry monitoring,ultimately improving patient outcomes and quality of care. 展开更多
关键词 Pulse oximetry Oxygen saturation Monitoring Advantages limitations Challenges RECOMMENDATIONS Clinical practice NON-INVASIVE CHILDREN
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Effects of nutrient limitations on the sinking velocity of Thalassiosira weissflogii
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作者 Jie Zhu Qiang Hao +2 位作者 Wei Zhang Yingying Ma Jiangning Zeng 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第6期163-172,共10页
The sinking of diatoms is critic al to the formation of oceanic biological pumps and coastal hypoxic zones.However,little is known about the effects of different nutrient restrictions on diatom sinking.In this study,w... The sinking of diatoms is critic al to the formation of oceanic biological pumps and coastal hypoxic zones.However,little is known about the effects of different nutrient restrictions on diatom sinking.In this study,we measured the sinking velocity(SV) of Thalassiosira weissflogii using a new phytoplankton video observation instrument and analyzed major biochemical components under varying nutrient conditions.Our results showed that the SV of T.weissflogii under different nutrient limitation conditions varied substantially.The highest SV of(1.77±0.02) m/d was obtained under nitrate limitation,signific antly surpassing that under phosphate limitation at(0.98±0.13) m/d.As the nutrient limitation was released,the SV steadily decreased to(0.32±0.03) m/d and(0.15±0.05) m/d,respectively.Notably;under conditions with limited nitrate and phosphate concentrations,the SV values of T.weissflogii significantly positively correlated with the lipid content(P <0.001),with R^(2) values of 0.86 and 0.69,respectively.The change of the phytoplankton SV was primarily related to the intracellular compo sition,which is controlled by nutrient conditions but did not significantly correlate with transparent extracellular polymer and biosilica contents.The results of this study help to understand the regulation of the vertical sinking process of diatoms by nutrient restriction and provide new insights into phytoplankton dynamics and their relationship with the marine nutrient structure. 展开更多
关键词 nutrient limitation Thalassiosira weissflogii sinking velocity biochemical component lipid content
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Assessment of the 2 Conventional Physiotherapy Sessions Alone versus One Session Associated to Kabat’s Method in the Rehabilitation of Buruli Ulcer Patients (PUB), with Functional Limitations in the District Hospital of Akonolinga, Cameroon
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作者 Fred Dikongue Dikongue Faustin Tsatedem Atemkeng +4 位作者 Joseph Fondop Jean Hubert Donfack Alain Djam Nkomo Banga Mbida Mpoame 《Surgical Science》 2023年第6期428-435,共8页
Buruli ulcer (BU) is a chronic, indolent necrotizing disease of the skin and underlying tissues caused by Mycobacterium ulcerans, which may result in functional disability. This disease is the third most frequent infe... Buruli ulcer (BU) is a chronic, indolent necrotizing disease of the skin and underlying tissues caused by Mycobacterium ulcerans, which may result in functional disability. This disease is the third most frequent infection after leprosy and tuberculosis caused by a mycobacterium. The main objective of this study was to determine comparative effectiveness of conventional physiotherapy alone to its association with Kabat’s method in the management of post-Buruli ulcer functional limitations. This was an interventional randomized, comparative and prospective study. It took place at the district hospital of Akonolinga from the 12<sup>th</sup> June to 12<sup>th</sup> September 2016. The study was included, post-Buruli ulcer patients who matched the eligibility criteria, were under treatment in the physiotherapy unit, and who accepted to participate in our study. A questionnaire on the socio-demographic profile of participants, the ulcer localization, the limitation stage, previous medical history and functional mobility assessment scale was administered to the subjects before and after the intervention which lasted for twelve weeks. We had 2 groups: the case group received association of Kabat technique to conventional physiotherapy and the control group received conventional physiotherapy alone. We had 22 patients, 11 patients for the experimental group, 11 patients for the control group. The mean age was 26.18 years, 54.5% of female participation, 68.2% of leg localization, 59.1% patients with severe limitations of functional mobility, and preference for traditional medication 95.5%. After evaluation of efficiency, we concluded that there was no statistically significant difference between the two treatment protocols. Further studies with larger sample size are recommended. 展开更多
关键词 Buruli Ulcer Functional limitations PHYSIOTHERAPY Kabat Technique
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Fully Distributed Nash Equilibrium Seeking for High-Order Players With Actuator Limitations 被引量:4
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作者 Maojiao Ye Qing-Long Han +1 位作者 Lei Ding Shengyuan Xu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第6期1434-1444,共11页
This paper explores the problem of distributed Nash equilibrium seeking in games, where players have limited knowledge on other players' actions. In particular, the involved players are considered to be high-order... This paper explores the problem of distributed Nash equilibrium seeking in games, where players have limited knowledge on other players' actions. In particular, the involved players are considered to be high-order integrators with their control inputs constrained within a pre-specified region. A linear transformation for players' dynamics is firstly utilized to facilitate the design of bounded control inputs incorporating multiple saturation functions. By introducing consensus protocols with adaptive and time-varying gains, the unknown actions for players are distributively estimated. Then, a fully distributed Nash equilibrium seeking strategy is exploited, showcasing its remarkable properties: (1) ensuring the boundedness of control inputs;(2) avoiding any global information/parameters;and (3) allowing the graph to be directed. Based on Lyapunov stability analysis, it is theoretically proved that the proposed distributed control strategy can lead all the players' actions to the Nash equilibrium. Finally, an illustrative example is given to validate effectiveness of the proposed method. 展开更多
关键词 Actuator limitation directed networks GAMES Nash equilibrium
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Potential and limitations of ChatGPT and generative artificial intelligence in medical safety education 被引量:1
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作者 Xin Wang Xin-Qiao Liu 《World Journal of Clinical Cases》 SCIE 2023年第32期7935-7939,共5页
The primary objectives of medical safety education are to provide the public with essential knowledge about medications and to foster a scientific approach to drug usage.The era of using artificial intelligence to rev... The primary objectives of medical safety education are to provide the public with essential knowledge about medications and to foster a scientific approach to drug usage.The era of using artificial intelligence to revolutionize medical safety education has already dawned,and ChatGPT and other generative artificial intelligence models have immense potential in this domain.Notably,they offer a wealth of knowledge,anonymity,continuous availability,and personalized services.However,the practical implementation of generative artificial intelligence models such as ChatGPT in medical safety education still faces several challenges,including concerns about the accuracy of information,legal responsibilities,and ethical obligations.Moving forward,it is crucial to intelligently upgrade ChatGPT by leveraging the strengths of existing medical practices.This task involves further integrating the model with real-life scenarios and proactively addressing ethical and security issues with the ultimate goal of providing the public with comprehensive,convenient,efficient,and personalized medical services. 展开更多
关键词 Medical safety education ChatGPT Generative artificial intelligence POTENTIAL LIMITATION
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Limitations of Lightning Rods in Preventing Direct Lightning Strikes 被引量:1
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作者 Zhen CHEN Xiaofeng LUO +5 位作者 Jixi LIU Ziqin GAO Yixian QIU Xiaoning ZHANG Lingjin KONG Chunliang ZHANG 《Meteorological and Environmental Research》 CAS 2023年第4期59-62,共4页
Since ancient times,lightning disasters have undoubtedly been an unstoppable threat to humanity.During thunderstorms,lightning often damages objects on the ground,such as buildings and structures.Since Franklin invent... Since ancient times,lightning disasters have undoubtedly been an unstoppable threat to humanity.During thunderstorms,lightning often damages objects on the ground,such as buildings and structures.Since Franklin invented the lightning rod in 1752,lightning rods have been used worldwide to prevent direct lightning strikes in various fields such as high-voltage power transmission lines,outdoor chemical sites,highways,land and sea wind farms,and forest lightning fire protection.It has been proven that lightning accidents still occur frequently in places where lightning rods are installed and the protective angle method is used.In order to further study the protective effect of lightning rods and identify the shortcomings of lightning rod protection,negative lightning strikes are taken as the research object,to analyze the limitations of lightning rods in preventing direct lightning strikes from the working principle of lightning rods. 展开更多
关键词 Lightning rod Direct lightning strike Protective angle method LIMITATION
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Current Limitations and Challenges with Lactic Acid Bacteria: A Review 被引量:14
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作者 Saeed A. Hayek Salam A. Ibrahim 《Food and Nutrition Sciences》 2013年第11期73-87,共15页
Lactic acid bacteria (LAB) play a critical role in food, agricultural, and clinical applications. The fast growing characteristics of LAB and their metabolic activity have been the key in most applications including f... Lactic acid bacteria (LAB) play a critical role in food, agricultural, and clinical applications. The fast growing characteristics of LAB and their metabolic activity have been the key in most applications including food production, agricultural industry, and probiotics. However, the biochemical and biophysical environments have significant effect on the growth and metabolic activity of LAB. While the biochemical conditions are most likely established, controlling and optimizing of biochemical conditions have many limitations and challenges. In addition to selecting the right strain, desirable metabolic processes required optimizing and controlling the available nutrients including sugars, peptides, free amino acids, minerals, and vitamins in addition to buffering agents. Thus, much of research was conducted to understand the impact of available nutrients on the growth and metabolic activities of LAB. However, only a few nutritional parameters could be controlled at a time while holding other parameters constant. The nutritional parameters may also interact with each other resulting in faulty results. Characteristics of LAB such as fastidiousness in their nutritional requirements, ability to produce acid and antimicrobial compounds, and variations in the nutritional requirements among strains have added additional limitations and challenges in this regard. Thus, chemically defined media (CDM) were suggested to deal with different limitations and challenges. However, due to differences in growth conditions, results obtained in CDM may face some obstacles when it comes to industrial applications. Thus, this paper aimed to review the recent data in regard to the role of the nutritional requirements of LAB in optimizing and controlling metabolic activities and to discuss the associated limitations and challenges. 展开更多
关键词 LACTIC Acid BACTERIA METABOLIC Activity NUTRITIONAL Requirements limitations CHALLENGES
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Limitations and potential design risks when applying empirically derived coal pillar strength equations to real-life mine stability problems 被引量:4
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作者 Russell Frith Guy Reed 《International Journal of Mining Science and Technology》 EI CSCD 2019年第1期17-25,共9页
The method of determining coal pillar strength equations from databases of stable and failed case histories is more than 50 years old and has been applied in different countries by different researchers in a range of ... The method of determining coal pillar strength equations from databases of stable and failed case histories is more than 50 years old and has been applied in different countries by different researchers in a range of mining situations. While common wisdom sensibly limits the use of the resultant pillar strength equations and methods to design scenarios that are consistent with the founding database, there are a number of examples where failures have occurred as a direct result of applying empirical design methods to coal pillar design problems that are inconsistent with the founding database. This paper explores the reasons why empirically derived coal pillar strength equations tend to be problem-specific and should be considered as providing no more than a pillar strength ‘‘index." These include the non-consideration of overburden horizontal stress within the mine stability problem, an inadequate definition of supercritical overburden behavior as it applies to standing coal pillars, and the non-consideration of overburden displacement and coal pillar strain limits. All of which combine to potentially complicate and confuse the back-analysis of coal pillar strength from failed cases. A modified coal pillar design representation and model are presented based on coal pillars acting to reinforce a horizontally stressed overburden, rather than suspend an otherwise unstable self-loaded overburden or section, the latter having been at the core of historical empirical studies into coal pillar strength and stability. 展开更多
关键词 Coal PILLAR DESIGN PILLAR strength OVERBURDEN MECHANICS limitations of PILLAR DESIGN
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Towards hepatitis C virus elimination:Egyptian experience,achievements and limitations 被引量:2
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作者 Dalia Omran Mohamed Alboraie +10 位作者 Rania A Zayed Mohamed-Naguib Wifi Mervat Naguib Mohamed Eltabbakh Mohamed Abdellah Ahmed Fouad Sherief Sahar Maklad Heba Hamdy Eldemellawy Omar Khalid Saad Doaa Mohamed Khamiss Mohamed El Kassas 《World Journal of Gastroenterology》 SCIE CAS 2018年第38期4330-4340,共11页
Worldwide, more than one million people die each year from hepatitis C virus(HCV) related diseases, and over 300 million people are chronically infected with hepatitis B or C. Egypt used to be on the top of the countr... Worldwide, more than one million people die each year from hepatitis C virus(HCV) related diseases, and over 300 million people are chronically infected with hepatitis B or C. Egypt used to be on the top of the countries with heavy HCV burden. Some countries are making advances in elimination of HCV, yet multiple factors preventing progress; remain for the majority. These factors include lack of global funding sources for treatment, late diagnosis, poor data, and inadequate screening. Treatment of HCV in Egypt has become one of the top national priorities since 2007. Egypt started a national treatment program intending to provide cure for Egyptian HCV-infected patients. Mass HCV treatment program had started using Pegylated interferon and ribavirin between 2007 and 2014. Yet, with the development of highly-effective direct acting antivirals(DAAs) for HCV, elimination of viral hepatitis has become a real possibility. The Egyptian National Committee for the Control of Viral Hepatitis did its best to provide Egyptian HCV patients with DAAs. Egypt adopted a strategy that represents a model of care that could help other countries with high HCV prevalence rate in their battle against HCV. This review covers the effects of HCV management in Egyptian real life settings and the outcome of different treatment protocols. Also, it deals with the current and future strategies for HCV prevention and screening as well as the challenges facing HCV elimination and the prospect of future eradication of HCV. 展开更多
关键词 Hepatitis C virus Egypt Direct ACTING ANTIVIRALS screening ELIMINATION limitations
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Coronary artery calcium data and reporting system: Strengths and limitations 被引量:1
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作者 Subramaniyan Ramanathan 《World Journal of Radiology》 CAS 2019年第10期126-133,共8页
Coronary artery calcium data and reporting system(CAC-DRS)is a recently introduced standardized reporting system for calcium scoring on computed tomography.CAC-DRS provides four risk categories(0,1,2 and 3)along with ... Coronary artery calcium data and reporting system(CAC-DRS)is a recently introduced standardized reporting system for calcium scoring on computed tomography.CAC-DRS provides four risk categories(0,1,2 and 3)along with treatment recommendations for each category.As with any other new reporting platform,CAC-DRS has both advantages and disadvantages.Improved communication,better clarity of details,organized management recommendations and utility in future research and education are the major strengths of CAC-DRS.It has many limitations such as questionable need for a new system,few missing components,use of a less accurate visual method and treatment suggestions based on expert opinion instead of clinical trials.In this contemporary review,we discuss the new reporting system CAC-DRS,its application,strengths and limitations and conclude with some remarks for the future. 展开更多
关键词 CORONARY ARTERY CALCIUM REPORTING system Agatston SCORE Strengths limitations Management
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The link between olfactory ensheathing cell survival and spinal cord injury repair: a commentary on common limitations of contemporary research 被引量:1
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作者 Ronak Reshamwala Megha Shah +1 位作者 James St.John Jenny Ekberg 《Neural Regeneration Research》 SCIE CAS CSCD 2020年第10期1848-1849,共2页
Olfactory ensheathing cells(OECs)are crucial players in the continuous regeneration of the olfactory nervous system that occurs through out life and are thought to have unique growth-promoting properties.For this reas... Olfactory ensheathing cells(OECs)are crucial players in the continuous regeneration of the olfactory nervous system that occurs through out life and are thought to have unique growth-promoting properties.For this reason,OEC transplantation has been thoroughly explored for the potential to promote neural repair after both central and peripheral nervous system injuries.Numerous studies have shown that OEC transplantation is safe and can promote recovery after spinal cord injury(SCI),both in animal models and in human clinical trials.To date,a variety of injury types and time-points after injury,as well as different delivery methods,have been tested.Outcomes have been encouraging(in rodent models including,for example,restoration of locomotion,breathing and climbing ability along with induction of axonal sprouting and some axonal regeneration)but highly variable(Barnett and Riddell,2007;Gomez et al.,2018). 展开更多
关键词 INJURIES injury limitations
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Role and limitations of rehabilitation-induced neural network remodeling after stroke 被引量:2
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作者 Naohiko Okabe Osamu Miyamoto 《Neural Regeneration Research》 SCIE CAS CSCD 2018年第12期2087-2088,共2页
There is plenty of evidence that proves the beneficial and reliable effects of rehabilitation therapy,making it the most common treatment for patients with chronic stroke.It is believed that rehabilitation improves fu... There is plenty of evidence that proves the beneficial and reliable effects of rehabilitation therapy,making it the most common treatment for patients with chronic stroke.It is believed that rehabilitation improves functional recovery through neural network remodeling,which is observed as a motor map reorganization or functional connectivity change assessed by intracortical microstimulation or functional magnetic resonance imaging(MRI). 展开更多
关键词 Role and limitations of rehabilitation-induced neural network remodeling after stroke
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Manipulated precipitation regulated carbon and phosphorus limitations of microbial metabolisms in a temperate grassland on the Loess Plateau,China
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作者 HAI Xuying LI Jiwei +4 位作者 LIU Yulin WU Jianzhao LI Jianping SHANGGUAN Zhouping DENG Lei 《Journal of Arid Land》 SCIE CSCD 2022年第10期1109-1123,共15页
Manipulated precipitation patterns can profoundly influence the metabolism of soil microorganisms.However,the responses of soil organic carbon(SOC)and nutrient turnover to microbial metabolic limitation under changing... Manipulated precipitation patterns can profoundly influence the metabolism of soil microorganisms.However,the responses of soil organic carbon(SOC)and nutrient turnover to microbial metabolic limitation under changing precipitation conditions remain unclear in semi-arid ecosystems.This study measured the potential activities of enzymes associated with carbon(C:β-1,4-glucosidase(BG)andβ-D-cellobiosidase(CBH)),nitrogen(N:β-1,4-N-acetylglucosaminidase(NAG)and L-leucine aminopeptidase(LAP))and phosphorus(P:alkaline phosphatase(AP))acquisition,to quantify soil microbial metabolic limitations using enzymatic stoichiometry,and then identify the implications for soil microbial metabolic limitations and carbon use efficiency(CUE)under decreased precipitation by 50%(DP)and increased precipitation by 50%(IP)in a temperate grassland.The results showed that soil C and P were the major elements limiting soil microbial metabolism in temperate grasslands.There was a strong positive dependence between microbial C and P limitations under manipulated precipitation.Microbial metabolism limitation was promoted by DP treatment but reversed by IP treatment.Moreover,CUE was inhibited by DP treatment but promoted by IP treatment.Soil microbial metabolism limitation was mainly regulated by soil moisture and soil C,N,and P stoichiometry,followed by available nutrients(i.e.,NO^(-)_(3),NH^(+)_(4),and dissolved organic C)and microbial biomass(i.e.,MBC and MBN).Overall,these findings highlight the potential role of changing precipitation in regulating ecosystem C turnover by limiting microbial metabolism and CUE in temperate grassland ecosystems. 展开更多
关键词 carbon use efficiency ecoenzymatic stoichiometry microbial metabolic limitations semi-arid ecosystems soil organic carbon
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Ethnic diversity, tax limitations and public goods
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作者 Steven M. Sheffrin Bei Li 《Chinese Business Review》 2009年第12期1-16,共16页
One strand of research in public economics has found that increasing ethnic diversity leads to reductions in provision of productive public goods. Another strand of research has emphasized the key role that tax and ex... One strand of research in public economics has found that increasing ethnic diversity leads to reductions in provision of productive public goods. Another strand of research has emphasized the key role that tax and expenditure limitations play in the provision of public services. This paper explores the interaction between these two effects. The regression results suggest that the prior results on ethnic diversity are robust when TELs are taken into consideration. In addition, the imposition of TELs mitigates the negative effect of ethnic fragmentation on the share of local spending on education and roads. It also mitigates the positive correlation between ethnic diversity and total local government revenue and expenditure per capita. 展开更多
关键词 public goods ethnic diversity tax and expenditure limitations
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Food Waste Management in Luxury Hotels-Best Practices and Limitations
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作者 Klára Morvay Karakas 《Journal of Environmental Science and Engineering(B)》 2021年第3期103-111,共9页
Hospitality industry and hotels are considered to waste a lot of food.This research aims to focus on food waste management in luxury hotels by investigating three luxury hotels in Budapest(Hungary).The investigation f... Hospitality industry and hotels are considered to waste a lot of food.This research aims to focus on food waste management in luxury hotels by investigating three luxury hotels in Budapest(Hungary).The investigation focuses on qualitative methods,eleven interviews and observations were made from September to December 2018.Results show that in luxury hotels the main challenge is to ensure the correct balance between 5*experience and minimizing food waste.It was found that kitchen,breakfast open-buffet and staff canteen are among the leading causes of food waste,generating even higher food waste compared to conferences,banquets,orála carte options.While a broad range of practices exist that are believed to minimize the food waste of buffets,most of the luxury hotels are only implementing a small ratio of such practices and are only in the beginning of the planning phase to expand their practices in this regard. 展开更多
关键词 Waste management food waste luxury hotel best practices limitations
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Advantages and Limitations of Translation Memory in Translation Teaching
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作者 黄薇 《海外英语》 2018年第15期149-150,共2页
With the rapid development of translation technology, great changes have taken place in translation teaching. The traditional translation teaching can not meet the needs of the market, and the market is in urgent need... With the rapid development of translation technology, great changes have taken place in translation teaching. The traditional translation teaching can not meet the needs of the market, and the market is in urgent need of translators who are proficient in information technology. Therefore, translation memory is gradually applied to translation teaching. Translation teaching has been liberated by translation memory to some extent. And translation memory makes translation teaching avoid a lot of repeated knowledge and processes of translation. It is no doubt that translation memory has some limitations. As a result, the advantages and limitations of translation memory in translation teaching are discussed. 展开更多
关键词 Computer-aided Translation Translation Memory Translation Teaching Advantages limitations
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Pancreatic neuroendocrine tumors: Therapeutic challenges and research limitations 被引量:4
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作者 Gabriel Benyomo Mpilla Philip Agop Philip +1 位作者 Bassel El-Rayes Asfar Sohail Azmi 《World Journal of Gastroenterology》 SCIE CAS 2020年第28期4036-4054,共19页
Pancreatic neuroendocrine tumors(PNETs)are known to be the second most common epithelial malignancy of the pancreas.PNETs can be listed among the slowest growing as well as the fastest growing human cancers.The preval... Pancreatic neuroendocrine tumors(PNETs)are known to be the second most common epithelial malignancy of the pancreas.PNETs can be listed among the slowest growing as well as the fastest growing human cancers.The prevalence of PNETs is deceptively low;however,its incidence has significantly increased over the past decades.According to the American Cancer Society’s estimate,about 4032(>7%of all pancreatic malignancies)individuals will be diagnosed with PNETs in 2020.PNETs often cause severe morbidity due to excessive secretion of hormones(such as serotonin)and/or overall tumor mass.Patients can live for many years(except for those patients with poorly differentiated G3 neuroendocrine tumors);thus,the prevalence of the tumors that is the number of patients actually dealing with the disease at any given time is fairly high because the survival is much longer than pancreatic ductal adenocarcinoma.Due to significant heterogeneity,the management of PNETs is very complex and remains an unmet clinical challenge.In terms of research studies,modest improvements have been made over the past decades in the identification of potential oncogenic drivers in order to enhance the quality of life and increase survival for this growing population of patients.Unfortunately,the majority of systematic therapies approved for the management of advanced stage PNETs lack objective response or at most result in modest benefits in survival.In this review,we aim to discuss the broad challenges associated with the management and the study of PNETs. 展开更多
关键词 Pancreatic neuroendocrine tumors Gastroenteropancreatic neuroendocrine tumors Management LIMITATION Novel Agents Emerging targets
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Effect of mass transfer limitations on catalyst performance during reduction and carburization of iron based Fischer-Tropsch synthesis catalysts 被引量:1
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作者 Akbar Zamaniyan Yadollah Mortazavi +1 位作者 Abbas Ali Khodadadi Ali Nakhaei Pour 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第5期795-803,共9页
Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pr... Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based catalysts.In this study,Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation method.To investigate the intraparticle mass transfer limitation under reduction,activation and reaction steps,and its effect on catalytic performance,catalyst pellets with different sizes of 6,3,1 and 0.5 mm have been prepared.All catalysts were calcined,pretreated and tested under similar conditions.The catalysts were activated in hydrogen (5%H2in N2) at 450℃ for 3 h and exposed to syngas (H2/CO=1) at 270℃ and atmospheric pressure for 40 h.Afterwards,FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290℃,17 bar and a feed flow (syngas H2/CO=1) rate of 3 L/h (STP).Using small pellets resulted in higher CO conversion,FT reaction rate and C5+ productivity as compared with larger pellets.The small pellets reached steady state conditions just 20 h after starting the reaction.Whereas for larger pellets,CO conversion,FT reaction rate and C5+ productivity increased gradually,and reached steady state and maximum values after 120 h of operation.The results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst activation.Also the results indicate that some effects of mass transfer limitations in activation step,can be compensated in the reaction step.The results can be used for better design of iron based catalyst to improve the process economy. 展开更多
关键词 FISCHER-TROPSCH mass transfer limitation activation catalyst GTL
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A joint inventory–finance model for coordinating a capital‑constrained supply chain with financing limitations 被引量:1
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作者 Faranak Emtehani Nasim Nahavandi Farimah Mokhatab Rafiei 《Financial Innovation》 2021年第1期115-153,共39页
Faced with economic recession,firms struggle to find ways to stay competitive and maintain market share.Effective coordination of the supply chain can solve this problem,but this may fail if existing capital constrain... Faced with economic recession,firms struggle to find ways to stay competitive and maintain market share.Effective coordination of the supply chain can solve this problem,but this may fail if existing capital constraints and financial flows are ignored.This study addresses the challenge by exploiting coordination through joint decision-making on the physical and financial flows of a capital-constrained supply chain.We also consider the capital-constrained member’s financing limitations that lead to lost sales.Two scenarios based on non-coordinated and coordinated structures are modeled in the form of bi-objective optimization problems that simultaneously optimize system costs and service levels.The models are solved using the-constraint method.The results indicate that the non-coordinated model cannot satisfy more than about 50%of the demand due to capital shortage and financing limitations,while the coordinated model can satisfy all of the demand via internal financing.Furthermore,the proposed coordination scheme leads to cost reduction for the members and the total system.To motivate all members to accept the proposed coordination scheme,a cost-sharing mechanism is applied to the coordination procedure.Finally,a sensitivity analysis concerning financial parameters is provided for validating the coordination model. 展开更多
关键词 Supply chain coordination Inventory-finance model Capital shortage Financing limitation Service level Bi-objective optimization
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The Limitations of Polygenic Hypothesis and Theorizing about Dual Multiple Factors and Three Normal Distributions 被引量:2
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作者 Tingzhen Zhang Xiaoming Jia Zhao Xu 《Applied Mathematics》 2016年第9期912-919,共8页
The original data of Nilsson-Ehle experiment in wheat were analyzed with existent genetic knowledge. It indicated that the core of polygenic hypothesis from this experiment was that a character similarity produced by ... The original data of Nilsson-Ehle experiment in wheat were analyzed with existent genetic knowledge. It indicated that the core of polygenic hypothesis from this experiment was that a character similarity produced by additive effect of multiple genes was the basis of continuous variation. Its precondition was for effective genes to have equal effect, to show merodominance and binomial distribution  and  to inherit independently. In fact, quantitative characters were determined by many genes with different property, effect and behavior. So it was difficult to solve all problems of continuous variation by the aid of polygenic hypothesis. The researchers should seek new ways. With Mendelian group as research object and by means of Lyapunov central limit theorem it was proved that both genotypic value G and the environmental effect in a niche E were subordinated to the normal distribution and respectively. According to additivity of the normal distribution the phenotype P = G + E also obeyed the normal distribution P = G + E ~  and quantitative characters showed continuous variation, whether or not the linkage was presented, whether or not every gene effect was equal, whether or not there were dominance and what kind of dominance between alleles. Moreover it was discussed that the quantitative characters in self-fertilized organism and clone were submitted to the normal distribution and presented continuous variation too. 展开更多
关键词 Inheritance of Quantitative Character Mendelian Population Central Limit Theorem Genotypic Value G Environmental Effect E Phenotype P Normal Distribution
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