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中国化肥需求弹性计算

上海农业学报 2012年第1期28卷 86-90页

作者：黄文芳 john k.dagsvik 复旦大学环境科学与工程系上海200433 挪威统计局研究部

为了分析国家政策对化肥消费的影响,选取1998-2007年不同省份单位面积化肥消费量、化肥价格指数以及农民纯收入为变量,对化肥支出函数进行了回归分析,计算出10年间不同省份化肥需求的价格弹性和收入弹性。结果表明:目前我国农业发展的... 详细信息

为了分析国家政策对化肥消费的影响,选取1998-2007年不同省份单位面积化肥消费量、化肥价格指数以及农民纯收入为变量,对化肥支出函数进行了回归分析,计算出10年间不同省份化肥需求的价格弹性和收入弹性。结果表明:目前我国农业发展的化肥基本消费量为0.35 t/hm^2,部分省份化肥消费过度;化肥市场还没有真正建立,价格对需求的影响较小。这表明化肥是农业经济发展的必需品,化肥施用量随农民收入的增加而增加,国家政策对化肥价格的干预是其需求不断上升的根本原因之一。这也在一定程度上说明仅通过环境税方式来改变农民化肥消费的政策效果有限,还需要转变现有的单纯促进农业经济发展的政策,朝着依据农民施肥方式是否有利于环境给予差异性补贴转变。

关键词：化肥价格需求弹性收入需求弹性

Surgical treatment of inflammatory bowel disease:From the gastroenterologist’s stand-point

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World Journal of Gastrointestinal Surgery 2024年第5期16卷 1235-1254页

作者： john k Triantafillidis Inflammatory Bowel Disease Unit “Metropolitan General”HospitalHolargos 15562AtticaGreece Hellenic Society of Gastrointestinal Oncology Haidari 12461AthensGreece

Treatment of ulcerative colitis(UC)and Crohn’s disease(CD)represents,in the majority of cases,a real challenge to the gastroenterologist’s abilities and skills as well as a clinical test concerning his/her levels of medical knowledge and *** the last two decades,our pharmaceutical arsenal was significantly strengthened,especially after the introduction of the so-called biological agents,drugs which to a large extent not only improved the results of conservative treatment but also changed the natural history of the ***,colectomy is still necessary for some patients with severe UC although smaller compared to the past,precisely because of the improvements achieved in the available conservative ***,surgeries to treat colon dysplasia and cancer are increasing to some *** the same time,satisfactory improvements in surgical techniques,the pre-and post-operative care of patients,as well as the selection of the appropriate time for performing the surgery have been *** patients with CD,the improvement of conservative treatment did not significantly change the need for surgical treatment since two-thirds of patients need to undergo surgery at some point in the course of their *** the other hand,the outcome of the operation has improved through good preoperative care as well as the wide application of more conservative surgical techniques aimed at keeping as much of the bowel in situ as *** article discusses the indications for surgical management of UC patients from the gastroenterologist’s point of view,the results of the emerging new techniques such as transanal surgery and robotics,as well as alternative operations to the classic ileo-anal-pouch *** author also discusses the basic principles of surgical management of patients with CD based on the results of the relevant *** self-evident is emphasized,that is,to achieve an excellent therapeutic result in patients with se

关键词： Inflammatory bowel disease Ulcerative colitis Crohn’s disease Surgery Treatment Ileo-anal-pouch anastomosis Indications Techniques

Immunotherapy of gastric cancer:Present status and future perspectives

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World Journal of Gastroenterology 2024年第8期30卷 779-793页

作者： john k Triantafillidis Manousos M konstadoulakis Apostolos E Papalois Inflammatory Bowel Disease Unit “Metropolitan General”HospitalHolargos 15562AtticaGreece.Hellenic Society for Gastrointestinal Oncology354 Iera OdosChaidari 12461AtticaGreece Second Department of Surgery University of Athens School of MedicineAretaieion HospitalAthens 11528AtticaGreece Unit of Surgical Research and Training Second Department of SurgeryUniversity of AthensSchool of MedicineAretaieion HospitalAthens 11528AtticaGreece

In this editorial,we comment on the article entitled“Advances and key focus areas in gastric cancer immunotherapy:A comprehensive scientometric and clinical trial review(1999-2023),”which was published in the recent issue of the World Journal of *** focused on the results of the authors’bibliometric analysis concerning gastric cancer immunotherapy,which they analyzed in depth by compiling the relevant publications of the last 20 *** that,we briefly describe the most recent data concerning the epidemiological parameters of gastric cancer(GC)in different countries,attempting to give an interpretation based on the etiological factors involved in the etiopathogenesis of the *** then briefly discuss the conservative treatment(chemotherapy)of the various forms of this malignant *** describe the treatment of resectable tumors,locally advanced neoplasms,and unresectable(advanced)*** attention is given to modern therapeutic approaches with emphasis on immunotherapy,which seems to be the future of GC treatment,especially in combination with *** is also a thorough analysis of the results of the study under review in terms of the number of scientific publications,the countries in which the studies were conducted,the authors,and the scientific centers of origin,as well as the clinical studies in ***,an attempt is made to draw some conclusions and to point out possible future directions.

关键词： Gastric cancer Chemotherapy Immunotherapy Immune checkpoint inhibitors Bibliometrics Scientometrics

Combination treatment of inflammatory bowel disease:Present status and future perspectives

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World Journal of Gastroenterology 2024年第15期30卷 2068-2080页

作者： john k Triantafillidis Constantinos G Zografos Manousos M konstadoulakis Apostolos E Papalois Inflammatory Bowel Disease Unit "Metropolitan General"HospitalHolargos 15562AtticaGreece Hellenic Society for Gastrointestinal Oncology 354 Iera OdosChaidari 12461AtticaGreece The 2^(nd)Department of Surgery University of AthensSchool of MedicineAretaieion HospitalAthens 11528Greece Unit of Surgical Research and Training The 2^(nd)Department of SurgeryUniversity of AthensSchool of MedicineAretaieion HospitalAthens 11528Greece

The treatment of patients with inflammatory bowel disease(IBD),especially those with severe or refractory disease,represents an important challenge for the clinical *** seems to be no exaggeration to say that in these patients,not only the scientific background of the gastroenterologist is tested,but also the abundance of“gifts”that he should possess(insight,intuition,determ-ination,ability to take initiative,etc.)for the successful outcome of the *** daily clinical practice,depending on the severity of the attack,IBD is treated with one or a combination of two or more pharmaceutical *** combin-ations include not only the first-line drugs(e.g.,mesalazine,corticosteroids,antibiotics,etc)but also second-and third-line drugs(immunosuppressants and biologic agents).It is a fact that despite the significant therapeutic advances there is still a significant percentage of patients who do not satisfactorily respond to the treatment ***,a part of these patients are going to *** recent years,several small-size clinical studies,reviews,and case reports have been published combining not only biological agents with other drugs(e.g.,immunosuppressants or corticosteroids)but also the combination of two biologi-cal agents simultaneously,especially in severe *** our opinion,it is at least a strange(and largely unexplained)fact that we often use combinations of drugs in a given patient although studies comparing the simultaneous administration of two or more drugs with monotherapy are very *** mentioned above,there is a timid tendency in the literature to combine two biological agents in severe cases unresponsive to the applied treatment or patients with severe extraintestinal *** appropriate dosage,the duration of the administration,the suitable timing for checking the clinical and laboratory outcome,as well as the treatment side-effects,should be the subject of intense clinical research *** this

关键词： Biologics for immune-mediated conditions Dual-targeted treatment Combination treatment Inflammatory bowel disease Crohn’s

Extractable and kerogen-bound hopanoids from typical Eocene oil shales in China

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Energy Geoscience 2024年第2期5卷 171-179页

作者： Changbo Zhai Zhirong Zhang john k.Volkman Hong Lu Yan'e Chen SINOPEC key Laboratory of Petroleum Accumulation Mechanisms Wuxi Institute of Petroleum GeologySINOPEC2060 Lihu RoadWuxiJiangsu213126China SINOPEC Petroleum Exploration and Production Research Institute 31 Xueyuan RoadBeijing100083China State key Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of ScienceGuangzhou510640GuangdongChina

This study conducted a comparative analysis of extractable hopanoid hydrocarbons and those released via stepwise pyrolysis of typical Eocene immature oil shales in China,namely the Huadian,Maoming,and Fushun *** the Huadian and Maoming shales exhibit immature indicators in extractable and kerogen-bound hopanoids(notably,high abundance of C_(29)to C_(32)17β,21β-hopanes and unsaturated hopenes).In contrast,the Fushun oil shale's hopanoids from extracts and pyrolyzates suggest a higher maturity *** absence of neohopenes in the pyrolyzates of the shales underpins that the kerogenbound hopanoid skeletons resist ***,the Huadian oil shale's asymmetric distribution of C_(29)and C_(30)hopenes and neohopenes hints at the presence of an additional *** unsaturated hopenes,such as hop-20(21)-enes,identified in pyrolyzates of the three kerogens at various pyrolysis temperatures,reveal the occurrence of double bonds in kerogen-bound hopanoid skeletons without methyl *** absence of hop-20-(21)-ene in extracts suggests that it might act as an intermediate of these novel hopenes during the epimerization of hopanoid skeletons within *** extractable and pyrolytic hopanoids'stereochemical alignment indicates that epimerization may occur in both ring systems and alkyl side chains of kerogen-bound hopanoid *** stepwise pyrolysis proves to be a quick screening method for geological hopanoids without causing any significant alteration to the original skeletons even when cracking multiple covalent bonds is necessary.

关键词： Hopanoid Hopane Hopene Neohopene Stepwise pyrolysis kerogen Eocene oil shale

Early-onset gastrointestinal cancer:An epidemiological reality with great significance and implications

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 583-597页

作者： john k Triantafillidis konstantinos Georgiou Manousos M konstadoulakis Apostolos E Papalois Department of IBD and GI Endoscopy Metropolitan General HospitalHolargos 15562AthensGreece.Hellenic Society for Gastrointestinal Oncology354 Iera OdosChaidari 12461AtticaGreece 2nd Department of Surgery University of Athens School of MedicineAretaieion HospitalAthens 11528Greece

During the last few years,epidemiological data from many countries suggest that the incidence and prevalence of many cancers of the digestive system are shifting from the older to the younger ages,the so-called“early-onset cancer”.This is particularly evident in colorectal cancer and secondarily in other malignant digestive neoplasms,mainly stomach and in a lesser degree pancreas,and biliary *** should be emphasized that data concerning digestive neoplasms,except for those referring to the colon and stomach,could be characterized as rather *** exact magnitude of the shift in younger ages is expected to become clearer shortly,as long as relevant epidemiological data from many parts of the world would be *** most important question concerns the etiology of this phenomenon,since its magnitude cannot be explained solely by the better diagnostic methodology and the preventive programs applied in many *** existing data support the assumption that a number of environ-mental factors may play a primary role in influencing carcinogenesis,sometimes from *** that have appeared in the last decades related mainly to eating habits,consistency of gut microbiome and an increase of obese people interacting with genetic factors,ultimately favor the process of *** these factors however,are not entirely sufficient to explain the age-related changes in the frequency of digestive *** of the individual effect of each of the already known factors or factors likely to be involved in the etiology of this phenomenon and studies using state-of-the-art technologies to accurately determine the degree of the population exposure to these factors are *** this article,we attempt to describe the epidemiological data supporting the age-shifting of digestive malignancies and their possible ***,we propose some measures regarding the attitude of the scientific community to this alarming phenomenon.

关键词： Gastrointestinal cancer Endoscopy Epidemiology Early-onset Environment

Experimental and analytical investigation on friction resistance force between buried coated pressurized steel pipes and soil

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 615-629页

作者： Shaurav ALAM Tanvir MANZUR john MATTHEWS Chris BARTLETT Erez ALLOUCHE Brent kEIL john kRAFT Department of Civil Engineering and Construction Engineering Technology Louisiana Tech UniversityRustonLA 71270USA Department of Civil Engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh Georgia Tech Research Institute AtlantaGA 30332USA Stantec Inc. Edmonton T5J0K4Canada North West Pipe Company VancouverWA 98684USA

This paper presents an analytical approach for estimating frictional resistance to pipe movement at soil and external pipe surface of buried coated pressurized steel pipes relative to the internal thrust *** proposed analytical method was developed based on 36 experiments,which involved three coating types(cement mortar(CM),polyurethane type-I(PT-I),prefabricated plastic tape(PPT))on pipes’surfaces,three different soils(pea-gravel(PG),sand(S),silty-clay(SC)),and four simulated over burden depths above the pipe’s *** showed frictional resistance decreased with increasing over burden depth above the pipe’s *** degree of frictional resistance at the pipe-soil interface was found to be in the order of PG>SC>S for all coating variations and overburden *** coated pipe buried in all three types of soil produced significantly higher frictional resistance as compared to other coating *** on experimental data,the developed analytical introduced a dimensionless factor“Z”,which included effects of types of coatings,soil,and overburden depths for simplified rapid *** showed that the method provided a better prediction of frictional resistance forces,in comparison to previous analytical methods,which were barely close in predicting friction resistance for different coating variations,soil types,and overburden *** resistance force values reported herein could be considered conservative.

关键词： friction resistance force thrust force coated pressurized steel pipe soil type overburden depth

Exploring Heat Sources Using Gravimetric Data: A Case Study of Magadi Geothermal Prospect, kenya

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Journal of Geoscience and Environment Protection 2024年第5期12卷 147-161页

作者： Evance Odero john Githiri Maurice k’Orowe Department of Physics Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

Understanding the location of the subsurface heat sources is crucial for efficient geothermal resource exploration and exploitation. This study aimed to investigate the faults and the depth to heat sources for a geothermal system in Magadi, southern Rift Valley, through the integration of gravity mapping, 3D Euler deconvolution, and spectral analysis. Gravity mapping is a powerful geophysical method widely used to infer subsurface density variations, which are indicative of geological structures and volcanic intrusions that can be potential heat sources. The Volcano-Tectonic and Fluvial-Deltaic Sedimentation process of the kenyan rift which encompasses the Magadi basin are responsible for geomorphic and geologic processes in the area. Alkali lava sheets of Magadi plateau trachytes covered with lacustrine sediments characterize 80% of the area. Deeper is the Tanzanian craton basement, overlain by Pliocene to Miocene volcanic and sedimentary rocks. A gravity survey with a data density of 2.375 stations/km2 produced high-resolution anomaly and total horizontal derivative maps showing gravity highs between −180 mGals to −174 mGals along the eastern zone of the study area. A buried major fault trending N-S was delineated in the mid-upper region of the area by Euler solutions at an average depth of 350 meters. Deeper features associated with possible volcanic dykes and sills gave Euler depth ranges of 0.7 km to 2.2 km. Radial average spectral analysis showed depth to the top of shallow and deep features at 2.4694 km and 5.827 km respectively. The correlation between gravity anomalies, geological structures, and present hot springs supports the hypothesis that volcanic processes have played a significant role in the development of the geothermal system in the study area.

关键词： Gravity Mapping 3D Euler Spectral Analysis Geothermal Magadi

Study of hybrid nanofluid flow in a stationary cone-disk system with temperature-dependent fluid properties

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 677-694页

作者： A.S.john B.MAHANTHESH G.LORENZINI Center for Mathematical Needs Department of MathematicsCHRIST(Deemed to be University)Karnataka 560029India School of Mathematical and Statistical Sciences The University of Texas Rio Grande ValleyTexas 78539U.S.A. Department of Engineering and Architecture University of ParmaParma 43124Italy

Cone-disk systems find frequent use such as conical diffusers,medical devices,various rheometric,and viscosimetry *** this study,we investigate the three-dimensional flow of a water-based Ag-Mg O hybrid nanofluid in a static cone-disk system while considering temperature-dependent fluid *** the variable fluid properties affect the dynamics and heat transfer features is studied by Reynolds's linearized model for variable viscosity and Chiam's model for variable thermal *** single-phase nanofluid model is utilized to describe convective heat transfer in hybrid nanofluids,incorporating the experimental *** model is developed as a coupled system of convective-diffusion equations,encompassing the conservation of momentum and the conservation of thermal energy,in conjunction with an incompressibility condition.A self-similar model is developed by the Lie-group scaling transformations,and the subsequent self-similar equations are then solved *** influence of variable fluid parameters on both swirling and non-swirling flow cases is ***,the Nusselt number for the disk surface is *** is found that an increase in the temperature-dependent viscosity parameter enhances heat transfer characteristics in the static cone-disk system,while the thermal conductivity parameter has the opposite effect.

关键词： hybrid nanofluid cone-disk system laminar flow variable fluid property Nusselt number