期刊文献+
共找到1,104篇文章
< 1 2 56 >
每页显示 20 50 100
基于循序渐进方式的Python-turtle库教学设计
1
作者 尹建新 胡彦蓉 《中国信息技术教育》 2024年第8期71-75,共5页
本文针对turtle绘图一堂课的实践教学,以任务为驱动,全面覆盖turtle知识点,以循序渐进方式将内容综合融入其中,结合线上线下混合式课堂,引导学生找到解决问题的方法,极大地提高了学生的编程兴趣,培养了学生的创新思维。
关键词 任务驱动 循序渐进 线上线下混合课堂 turtle
下载PDF
Separation and Identification of Pathogens Causing Soft-shelled Turtle Fulminant Infectious Disease and Preparation of Anti-Aeromonas Serum
2
作者 高桂生 史秋梅 +2 位作者 张艳英 高光平 陈翠珍 《Agricultural Science & Technology》 CAS 2012年第10期2155-2158,2205,共5页
[Objective] This study aimed to isolate and identify the pathogens of soft-shelled turtle fulminant infectious disease,to provide the basis for the prevention and control of aquatic animal diseases.[Method] Commercial... [Objective] This study aimed to isolate and identify the pathogens of soft-shelled turtle fulminant infectious disease,to provide the basis for the prevention and control of aquatic animal diseases.[Method] Commercially available sick soft-shelled turtles were used as experimental materials,to isolate and identify the causative pathogens;pathogenicity test and toxin determination of the isolates were carried out;in addition,hyperimmune serum was prepared and its therapeutic effect was detected.[Result] Nine bacteria were isolated from the livers of sick soft-shelled turtles,including seven Aeromonas sobria strains(JA-1) and two A.caviae strains(JA-2).The median lethal dose(LD50) of JA-1 and JA-2 was 4.3×10^5/ml and 5.5×10^7/ml,respectively;the broth culture supernatant of the two bacteria contains a type of toxin with hemolytic activity,indicating that the soft-shelled turtle fulminant infectious disease is caused by A.sobria and A.caviae.Vaccine was prepared by using the two bacteria and rabbit immunization with immunopotentiator,showing a titer of 1:512 and a cure rate of 100%.[Conclusion] This study laid foundation for the prevention and control of aquatic animal diseases. 展开更多
关键词 turtle AEROMONAS SERUM
下载PDF
Tracking the Confiscated Green Sea Turtles in the South China Sea:Where Did They Come From?Where Will They Go?
3
作者 Min CHEN Tong HUANG +7 位作者 Dayi NIE Liu LIN Fang CHEN Jing WANG Jinyan YANG Jing ZHANG Tong LIU Yiqiong CUI 《Asian Herpetological Research》 SCIE CSCD 2024年第3期173-182,共10页
The population of the green sea turtle(Chelonia mydas)is under decline,threatened by bycatch and illegal acquisition despite worldwide protection efforts.However,the confiscation of illegally acquired sea turtles coul... The population of the green sea turtle(Chelonia mydas)is under decline,threatened by bycatch and illegal acquisition despite worldwide protection efforts.However,the confiscation of illegally acquired sea turtles could aid in tracking their origin and movement patterns,crucial for effective conservation strategies.Combining satellite tracking and genetic analysis offers an opportunity to investigate the relationship between the origins and migration directions of green sea turtles in the western Pacific.Here,we applied two methods to investigate the spatial ecology of 18 green turtles caught as bycatch in the South China Sea.Our results revealed the genetic origins and diverse movements of the turtles.Bayesian Mixed Stock Analysis(MSA)suggested that these turtles originated from the rookery of the Xisha Islands(49.6%),central Ryukyu(24.6%),NE Borneo(8%),and the Sulu Sea(5.2%),with other rookeries in meagre proportions(<2%each).Satellite tracking showed the ranges of their travel were smaller than the whole contributed rookery range,but diverse.The haplotype diversity of these turtles is high,and CmP19 stands out as both the most frequent and the most diverse haplotype in terms of swimming destinations.These results indicate that the South China Sea is likely an important transportation hub and mating spot for green turtles.Our findings provided evidence for the rehabilitation of these green turtles in the wild and illustrated the complexity of movement during the green turtle’s life history,and the“mixed backgrounds”of the green turtles also highlight the need for joint conservation efforts of neighbouring countries in the South China Sea. 展开更多
关键词 conservation GENETICS green sea turtle(Chelonia mydas) movement rookery satellite tracking
下载PDF
The first record of dermochelyid turtles in the Eocene of Tierra del Fuego:new insights on the evolution of the Weddellian faunas
4
作者 Paula BONA Juliana STERLI +3 位作者 Marcelo Saúl de la FUENTE Eduardo OLIVERO Marta S.FERNÁNDEZ Marcelo REGUERO 《Advances in Polar Science》 CSCD 2024年第1期63-77,共15页
The Antarctic Paleogene marine fossil record has been the key to reconstructing the evolution of the Weddellian Sea and final dismemberment of Southern Gondwana.In this context,Eocene marine vertebrates from Seymour(M... The Antarctic Paleogene marine fossil record has been the key to reconstructing the evolution of the Weddellian Sea and final dismemberment of Southern Gondwana.In this context,Eocene marine vertebrates from Seymour(Marambio)Island have provided valuable information.We present the first Eocene record of marine reptiles from the southern Atlantic Coast of South America.This corresponds to several postcranial turtle remains represented by a proximal end of the right humerus,three caudal and one thoracic vertebrae,a fragment of the left pubis,and ten ossicles of the dorsal carapace,coming from the Leticia Formation(late-mid Eocene)at Cabo Tiburones,Tierra del Fuego,Argentina.These materials show severalfeatures such as the size and general morphology of the humerus and vertebrae,and the presence of relatively small,irregular,smooth,and unkeeled ossicles,which allow us to assign them to Dermochelyidae indet.Dermochelyids are a cosmopolitan group ofcryptodiran turtles,registered from the late Cretaceous up to the recent,with some physiological-biological peculiarities(e.g.,endothermy and an exclusive jellyfish-based diet)and characterized by the presence of an osseous carapace formed by ossicles.The new finding from the Leticia Formation is an addition to the scarce and extremely fragmentary record of Eocene dermochelyids from the southern seas like those from the La Meseta and Submeseta formations(Antarctica)and the Waihao and Burnside formations(New Zealand).This new information allows us to discuss the presence of these turtles in such high latitudes in the past and its implication in the evolution of the Weddellian fauna. 展开更多
关键词 marine reptiles sea turtles Dermochelyidae PALEOGENE La Meseta Formation Submeseta Formation Leticia Formation
下载PDF
White-spot disease of Chinese soft-shelled turtles (Trionyx sinens) caused by Paecilomyces lilacinus 被引量:8
5
作者 Xiao-liang LI Chu-long ZHANG +1 位作者 Wei-huan FANG Fu-cheng LIN 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2008年第7期578-581,共4页
Chinese soft-shelled turtles (Trionyx sinens) in culture farms using an artificial warming system in Zhejiang, China, often show typical signs of white-spot disease such as white spots on their bodies, skin lesions,... Chinese soft-shelled turtles (Trionyx sinens) in culture farms using an artificial warming system in Zhejiang, China, often show typical signs of white-spot disease such as white spots on their bodies, skin lesions, anorexia and eventually death. The sick turtles were mostly 5-80 g in weight. A suspected fungal pathogen was isolated from the sick turtles and verified as Paecilomyces lilacinus by sequence analysis of the internal transcribed spacer (ITS) of its ribosomal DNA (rDNA). Detailed morphological examinations were also conducted to confirm the white-spot disease. 展开更多
关键词 White-spot disease Chinese soft-shelled turtles Paecilomyces lilacinus ZHEJIANG
下载PDF
Effects of Brown Fish Meal Replacement with Fermented Soybean Meal on Growth Performance, Feed Efficiency and Enzyme Activities of Chinese Soft-shelled Turtle, Pelodiscus sinensis 被引量:7
6
作者 ZOU Yurong AI Qinghui +3 位作者 MAI Kangsen ZHANG Wenbing ZHANG Yanjiao XU Wei 《Journal of Ocean University of China》 SCIE CAS 2012年第2期227-235,共9页
A 120-day feeding experiment was conducted to investigate the effects of partial replacement of brown fish meal (BFM) by fermented soybean meal (FSBM) in diets of Chinese soft-shelled turtle (Pelodiscus sinensis). The... A 120-day feeding experiment was conducted to investigate the effects of partial replacement of brown fish meal (BFM) by fermented soybean meal (FSBM) in diets of Chinese soft-shelled turtle (Pelodiscus sinensis). The turtles (initial mean body weight, (115.52 ± 1.05) g) were fed with three experimental diets, in which 0%, 4.72% and 9.44% BFM protein was replaced by 0%, 3% and 6% FSBM, respectively. Results showed that the feeding rate (FR), specific growth rate (SGR) and feed efficiency ratio (FER) of turtles fed with the diet containing 3% FSBM were not significantly different from the control group (0% FSBM) (P > 0.05). However, FR, SGR and FER of turtles fed with the diet containing 6% FSBM were significantly lower than those of the control group (P < 0.05). No significant differences were observed in the activities of serum glutamic-oxalacetic transaminase and glutamicpyruvic transaminase among dietary treatments (P > 0.05). However, the uric acid concentration in turtles fed with the diet containing 3% or 6% FSBM was significantly lower than that in the control group (P < 0.05). There were no significant differences in the activities of lysozyme, alkaline phosphatase and total superoxide dismutase among dietary treatments (P > 0.05). The results suggested that FSBM could replace 4.72% BFM protein in turtle diets without exerting adverse effects on turtle growth, feed utilization and measured immune parameters. 展开更多
关键词 Chinese soft-shelled turtle Pelodiscus sinensis brown fish meal REPLACEMENT fermented soybean meal
下载PDF
Effects of ration level and feeding frequency on digestibility in juvenile soft-shelled turtle, Pelodiscus sinensis 被引量:1
7
作者 LEI Si-jia 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2006年第7期580-585,共6页
The effects of ration level and feeding frequency on digestibility in juvenile soft-shelled turtle, Pelodiscus sinensis, were investigated. Four ration levels 1.5%, 2.5%, 4.0% and satiation (6.0% BW/d) were used. Ap... The effects of ration level and feeding frequency on digestibility in juvenile soft-shelled turtle, Pelodiscus sinensis, were investigated. Four ration levels 1.5%, 2.5%, 4.0% and satiation (6.0% BW/d) were used. Apparent digestibility (AD) of dry matter (DMAD), protein (PAD) and protein real digestibility (PRD) were significantly affected by ration level, but not by feeding frequency when the ration level was similar. However, the feeding frequency affected the AD, DMAD, PAD and PRD significantly when the turtles were fed to satiation. The relationship between fecal protein content (Y) and protein intake (At) can be expressed as a quadric equation: Y=-0.1742+0.1476X-0.0003X^2 (r^2=0.876, n=27, F=93.92, P〈0.01). 展开更多
关键词 DIGESTIBILITY Ration level Feeding frequency Juvenile soft-shelled turtle Pelodiscus sinensis
下载PDF
Physiological responses in vitamin C system during hibernation in juvenile Chinese soft-shelled turtle Pelodiscus sinensis 被引量:1
8
作者 CHEN Bojian NIU Cuijuan +1 位作者 YUAN Lin ZHANG Wenyi 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2019年第2期767-776,I0001-I0011,共11页
Vitamin C (Vc) is an important antioxidant that helps turtles tolerating stressful environment. This work quantified changes in tissue Vc levels during winter hibernation in the soft-shelled turtle Pelodiscus sinensis... Vitamin C (Vc) is an important antioxidant that helps turtles tolerating stressful environment. This work quantified changes in tissue Vc levels during winter hibernation in the soft-shelled turtle Pelodiscus sinensis , to reveal the stress response pattern of tissue Vc during hibernation and contribute basic data for turtle culture. We sampled juvenile soft-shelled turtles at pre-hibernation (17.0°C mud temperature;MT), during hibernation (5.8°C MT) and after arousal (20.1°C MT) in the field. The transcript levels of the gene encoding L-gulonolactone oxidase (GLO), the key enzyme for Vc synthesis, decreased significantly during hibernation. However, GLO activity did not match the GLO transcription patterns and remained stable during hibernation, and showed temperature-dependent kinetic characteristics. Vitamin C levels in the brain, liver, kidney, and spleen (but not muscle) all decreased significantly during hibernation, but recovered to pre-hibernation levels or even higher levels after arousal. The soft-shelled turtle endured 5 months of hibernation with no significant oxidative damage in most tissues, except in the spleen. Splenic Vc was nearly exhausted during hibernation, accompanied by a significantly elevated malonaldehyde (MDA) level. Although the high level of oxidative damage quickly decreased after arousal, the potential tissue damage in the spleen during hibernation might account for the weakened immune capacity of turtles after hibernation. 展开更多
关键词 CHINESE soft-shelled turtle HIBERNATION reactive oxygen species (ROS) L-gulonolactone OXIDASE oxidative stress
下载PDF
Effects of Dietary Soy Protein Concentrate on Growth, Digestive Enzymes Activities and Target of Rapamycin Signaling Pathway Regulation in Juvenile Soft-Shelled Turtle, <i>Pelodiscus sinensis</i> 被引量:3
9
作者 Fan Zhou Yaqin Wang +3 位作者 Li Tang Yong Huang Xueyan Ding Zhongyang He 《Agricultural Sciences》 2015年第3期335-345,共11页
Soft-shelled turtle, Pelodiscus sinensis is important aquatic species in China, and searching for alternatives protein resources to fish meal (FM)-based feeds in feed has become urgent and important for its sustainabi... Soft-shelled turtle, Pelodiscus sinensis is important aquatic species in China, and searching for alternatives protein resources to fish meal (FM)-based feeds in feed has become urgent and important for its sustainability development. The present study was conducted to assess the effects of dietary soy protein concentrate (SPC) on growth, digestive enzymes and target of rapamycin (TOR) signaling pathway of juvenile P. sinensis (4.56 ± 0.09 g). SPC was applied to replace FM protein at 0%, 15%, 30% and 60% (designated as T0, T15, T30 and T60, respectively), and each diet was fed to triplicate groups. The results showed that there was no significant difference in growth performance and feed utilization except of the turtles fed with T60 diet, of which showed poorer daily weight gain and feed conversion rate. The pepsin/trypsin and Na+-K+ ATP-ase activities decreased dramatically when SPC level increased, and lipase activities in liver and intestinal tract also showed decline tendency. However, amylase activities were unaffected. No significant differences were observed in TOR, S6K1 and 4E-BP1 genes mRNA expression level of TOR signaling pathway among the treatments. However, the relative phosphorylated level of these proteins decreased significantly when SPC level increased. The present study indicated that high SPC substitution level would suppress digestive enzymes and TOR signaling pathway proteins phosphorylated level and eventually result in growth reduction of P. sinensis. 展开更多
关键词 soft-shelled turtle P. sinensis Soy Protein Concentrate GROWTH Performance DIGESTIVE Enzymes Target of Rapamycin Signaling Pathway
下载PDF
基于Python语言的Turtle库绘图实例 被引量:2
10
作者 林晓芬 《电脑知识与技术》 2023年第3期97-98,102,共3页
Python语言语法简洁、清晰、易读。学生在学习Python语言时,学习难度起点低,容易入门。国内许多高校都开设了Python程序设计课程。Python语言的Turtle库设计巧妙,作图模型简单强大。初学者能很快编写出趣味生动的作图程序,极大地提高了... Python语言语法简洁、清晰、易读。学生在学习Python语言时,学习难度起点低,容易入门。国内许多高校都开设了Python程序设计课程。Python语言的Turtle库设计巧妙,作图模型简单强大。初学者能很快编写出趣味生动的作图程序,极大地提高了学习者的兴趣和积极性。 展开更多
关键词 PYTHON语言 turtle
下载PDF
A Meta-analysis of the spirit turtle eight method Acupuncture Therapy for Insomnia
11
作者 CHEN Bo-xin ZENG Nian-peng +1 位作者 KUANG Yu-lian ZHAO Cai-jiao 《Journal of Hainan Medical University》 CAS 2023年第7期61-68,共8页
Objective:To systematically evaluate the efficacy and safety of the spirit turtle eight method acupuncture therapy in the treatment of insomnia,to better serve the clinic and provide reference ideas for the treatment ... Objective:To systematically evaluate the efficacy and safety of the spirit turtle eight method acupuncture therapy in the treatment of insomnia,to better serve the clinic and provide reference ideas for the treatment of insomnia.Methods:Search CNKI,CBM,Wanfang,Weipu,China Clinical Trial Registry databases on the use of the spirit turtle eight method compared with others interventions to treat insomnia.The search period is from the library until August 1,2021,two researchers will conduct independent quality evaluation and effect size extraction on the literature,and use STATA16.0 and Review5.3 to conduct Meta analysis and quality evaluation on the literature.Through screening,a total of 18 eligible documents participated in the meta-analysis,with a total of 1583 cases.Results:①The effective rate of the spirit turtle eight method in the treatment of insomnia is higher than the control group[RR=1.213,95%CI(1.155,1.274),Z=7.71,P<0.01];②The Pittsburgh Sleep Quality Index(PSQI)score is lower than other acupuncture treatments[WMD=-2.33,95%CI(-2.75,-1.91),Z=10.97,P<0.01];③The one-month follow-up PSQI score after the treatment of insomnia by the spirit turtle eight method is lower than the control group[WMD=-3.263,95%CI(-3.446,-3.080),Z=34.96,P<0.01];④No studies have reported serious adverse reactions in the treatment group and control group.Conclusion:Based on the current research,the spirit turtle eight method are better than the control group in the treatment of insomnia,and are suitable for clinical application.However,more high-quality clinical studies are still needed to prove its efficacy. 展开更多
关键词 Spirit turtle eight method Acupuncture Treatment INSOMNIA Meta Analysis
下载PDF
利用Python语言的Turtle库绘制正多变形 被引量:3
12
作者 林晓芬 《电脑知识与技术》 2020年第22期111-113,共3页
Python语言是目前最接近自然语言的通用编程语言,目前受关注度非常高,国内许多高校都开设了Python程序设计课程。Python语言的Turtle库是一个简单、易用的绘图库,可以用作Python语言学习的入门库。通过选取一些有趣的绘图案例,来增强学... Python语言是目前最接近自然语言的通用编程语言,目前受关注度非常高,国内许多高校都开设了Python程序设计课程。Python语言的Turtle库是一个简单、易用的绘图库,可以用作Python语言学习的入门库。通过选取一些有趣的绘图案例,来增强学生学习语言的兴趣。 展开更多
关键词 PYTHON语言 turtle
下载PDF
Turtle海龟画图之螺旋线 被引量:2
13
作者 林晓芬 《电脑知识与技术》 2020年第32期199-201,共3页
Python语言是目前最接近自然语言的通用编程语言,目前受关注度非常高,国内许多高校都开设了Python程序设计课程。Python语言的Turtle库是一个简单、易用的绘图库,可以用作Python语言学习的入门库。通过选取一些有趣的绘图案例,来增强学... Python语言是目前最接近自然语言的通用编程语言,目前受关注度非常高,国内许多高校都开设了Python程序设计课程。Python语言的Turtle库是一个简单、易用的绘图库,可以用作Python语言学习的入门库。通过选取一些有趣的绘图案例,来增强学生学习Python编程语言的兴趣。 展开更多
关键词 PYTHON语言 turtle
下载PDF
Python语言的Turtle库简介
14
作者 林晓芬 《电脑编程技巧与维护》 2022年第9期40-41,73,共3页
Python语言语法简洁、清晰、易读。学生在学习Python语言时,学习难度起点低,容易入门,国内许多高校都开设了Python程序设计课程。Python语言的Turtle库设计巧妙,作图模型简单强大。初学者很快能编写出趣味生动的作图程序,极大地提高了... Python语言语法简洁、清晰、易读。学生在学习Python语言时,学习难度起点低,容易入门,国内许多高校都开设了Python程序设计课程。Python语言的Turtle库设计巧妙,作图模型简单强大。初学者很快能编写出趣味生动的作图程序,极大地提高了学习者的兴趣和积极性。 展开更多
关键词 PYTHON语言 turtle
下载PDF
Effects of Pesticide Exposure on Embryonic Development and Hatchling Traits of Turtles 被引量:5
15
作者 Baofeng WU Liang LIANG +1 位作者 Liang MA Weiguo DU 《Asian Herpetological Research》 SCIE CSCD 2016年第1期28-33,共6页
Deltamethrin is a widespread environmental hormone with endocrine-disrupting properties, but its effect on embryonic development of reptiles is largely unexplored. We investigated the effects of deltamethrin on embryo... Deltamethrin is a widespread environmental hormone with endocrine-disrupting properties, but its effect on embryonic development of reptiles is largely unexplored. We investigated the effects of deltamethrin on embryonic development and offspring traits in two turtle species, one with parchment-shelled eggs and the other with rigidshelled eggs. Deltamethrin exposure during egg incubation did not affect hatching success and hatchling body size in either species. However, embryonic exposure to deltamethrin resulted in reduced hatchling locomotor performance in the red-eared slider turtle(Trachemys scripta) with parchment-shelled eggs, but not in the Chinese three-keeled pond turtle(Chinemys reevesii) with rigid-shelled eggs. These results suggest that parchment-shelled eggs are likely more vulnerable to deltamethrin than rigid-shelled eggs. 展开更多
关键词 Parchment-shelled eggs Rigid-shelled eggs Red-eared slider turtle Trachemys scripta Chinese threekeeled pond turtle Chinemys reevesii Embryo Environmental hormone
下载PDF
Captive Breeding of the Four-eyed Turtle(Sacalia quadriocellata) 被引量:2
16
作者 HE Bin LIU Yuxiang +8 位作者 SHI Haitao ZHANG Jie HU Maogui MA Yonggang FU Lirong HONG Meiling WANG Jichao Fong J.Jonathan Parham F.James 《Asian Herpetological Research》 SCIE 2010年第2期111-117,共7页
In 1998,a study on forty-five four-eyed turtles(Sacalia quadriocellata) was initiated to gather preliminary biological data of this species and to investigate the feasibility of its captive reproduction.In the followi... In 1998,a study on forty-five four-eyed turtles(Sacalia quadriocellata) was initiated to gather preliminary biological data of this species and to investigate the feasibility of its captive reproduction.In the following six years,no courtship behavior was found occurring in males and no oviposition in females.From 2004 to 2007,two successful techniques were applied to initiate reproductive behavior:1) injecting exogenous reproductive hormones; and 2) reducing the stress of living in captivity.As a result of the hormone treatments,courtship behavior and copulation were observed during September and October,2005.However,no courtship displays were seen from the CK males,which were not treated with hormones.Ovulation occurred between December and March,and the correlation was not significant between behavior of ovulation and food intake.Females laid only one clutch of eggs each year,with 2.47 eggs(n=34,range=1–4) at average,and 84 eggs were totally obtained,of which 13 were damaged,52 were infertile and 19 fertile.Of the fertile eggs,nine were hatched with mean incubation period of 105.9 days(n=9,range=89–122 days) at temperature ranging from 24 to 27℃. 展开更多
关键词 four-eyed turtle Sacalia quadriocellata captive breeding HORMONE STRESS CONSERVATION
下载PDF
Structure and Function of the Gastrointestinal Tract of the Green Turtle(Chelonia mydas) Hatchling 被引量:1
17
作者 Hualing CHEN Mingbin YE +3 位作者 Yuyan LU Jinxia DUAN Pipeng LI Hexiang GU 《Asian Herpetological Research》 SCIE CSCD 2015年第4期317-330,共14页
The gastrointestinal tracts of four Chelonia mydas hatchlings were examined at the anatomical, histological and ultrastructural level. Our results show that the gastrointestinal tract(GI) is composed by esophagus, s... The gastrointestinal tracts of four Chelonia mydas hatchlings were examined at the anatomical, histological and ultrastructural level. Our results show that the gastrointestinal tract(GI) is composed by esophagus, stomach, small intestine(SI) and large intestine(LI), and histologically of mucosa, submucosa, muscularis externa(ME) and serosa. The esophagus is marked by conical papillae lined by keratinized stratified squamous epithelium, whereas the remaining GI by simple columnar epithelium; esophageal diverticulum is absent. The stomach covered with mucous granule cells, contains cardia, fundic regions and pylorus, which are separately characterized by cardiac glands, fundic glands and pyloric glands, and have the thickest submucosa and ME of the GI. The ME of the esophagus mainly consist of one layer of circular smooth muscle whereas the rest of GI of two layers, inner circular muscle and outer longitudinal muscle. The SI is slightly longer than the LI and the GI is approximately 5.11 times of the carapace length. The SI is lined with longitudinal zigzag folds and characterized by absorptive cells with longer and denser microvilli, whereas the LI by transversal folds, goblet cells and lymphoid nodules. Only intestinal glands appear in duodenum. Endocrine cells are observed in all sections of the GI and accounted for the largest proportion in duodenum. The results demonstrate a perfect combination of the structure and function of the GI and reveal that the digestion and absorption primarily occurs in the foregut. C. mydas hatchling may prefer carnivorous diet. 展开更多
关键词 ANATOMY HISTOLOGY ULTRASTRUCTURE digestive tract DIET sea turtle
下载PDF
Effect of Incubation Temperature on the Somatic Development of the Snail-Eating Turtle Malayemys macrocephala 被引量:1
18
作者 Rangsima PEWPHONG Jirarach KITANA Noppadon KITANA 《Asian Herpetological Research》 SCIE 2013年第4期254-262,共9页
The rising average global temperature can lead to changes both in the physical and biological environments and affect the survival of organisms. Freshwater turtles are considered to be susceptible species since their ... The rising average global temperature can lead to changes both in the physical and biological environments and affect the survival of organisms. Freshwater turtles are considered to be susceptible species since their development is dependent on incubation temperature. In Thailand, although several species of freshwater turtle are present, the extent of their susceptibility to temperature change is unknown due to the lack of information on their developmental patterns. This research, therefore, is aimed at examining the effects of temperature on somatic development in Malayemys macrocephala, a native species and the most common freshwater turtle in Thailand. Turtle eggs were collected from rice fields in the central part of Thailand during December 2011 to February 2012 inclusive. Eggs (237-238 per condition) were incubated in microprocessor-controlled incubators at three different temperatures (26 ℃, 29℃ and 32℃) with a relative humidity in excess of 80%. Each week, until the remaining eggs hatched, eggs were randomly selected, removed and dissected to reveal the developing embryo to screen for developmental stage and any abnormalities. The incubation period (lay to hatch) was not significantly different among the three temperatures (115 ±11.3 d, 115 ±20.3 d and 109±17.8 d, respectively), but the growth patterns, as indicated by the stages of development and carapace lengths, were significantly different. At a high temperature (32℃), turtle embryos showed a significantly faster growth rate than at the intermediate and low temperatures (29 ℃and 26 ℃), but had a significantly (over 3.3-fold) higher incidence of developmental abnormalities (especially deformed bodies) than at the lower temperatures. Overall, the results indicate that incubation temperature is an important variable affecting the somatic development of this tropical freshwater turtle species, whilst abnormalities in the embryonic body may be a sensitive indicator of extreme thermal stress. 展开更多
关键词 ABNORMALITY egg incubation embryonic stage freshwater turtle growth
下载PDF
The Effect of the Cyp19a1 Gene Methylation Modification on Temperature-dependent Sex Determination of Reeves' Turtle(Mauremys reevesii) 被引量:1
19
作者 Wenxiu RU Liushuai HUA +6 位作者 Yufeng WEI Weiye LI Dainan CAO Yan GE Hong CHEN Xianyong LAN Shiping GONG 《Asian Herpetological Research》 SCIE CSCD 2017年第3期213-220,共8页
Temperature-dependent sex determination(TSD) is a type of environmental sex determination in which the sex of the embryos depends on the ambient temperature; however,the molecular mechanisms governing this process r... Temperature-dependent sex determination(TSD) is a type of environmental sex determination in which the sex of the embryos depends on the ambient temperature; however,the molecular mechanisms governing this process remain unknown.Aromatase,encoded by the cyp19a1 gene,which converts androgens into estrogens in animals,was considered to be the key gene for TSD.In this study,the 5'-flanking region of the cyp19a1 gene in Reeves' turtle(Mauremys reevesii) was cloned,and the promoter region was identified using the luciferase reporter assay.Then the eggs of Reeves' turtle were incubated at different temperatures(26°C: male-biased temperature; 29°C: non-sex-biased temperature and 32°C: female-biased temperature).During the thermosensitive period,the adrenal kidney gonad complexes(AKG) were sampled.DNA methylation analysis of the AKG samples showed that the promoter region of the cyp19a1 gene was significantly de-methylated in the female-biased temperature regime(P&lt;0.01).Quantitative analysis of the cyp19a1 gene and estrogen by q PCR and Elisa assay showed that the expression level of the cyp19a1 gene and estrogen content were both upregulated significantly at the female-biased temperature(P&lt;0.01).These results indicated that the de-methylation response of the cyp19a1 gene to incubation temperature,especially at the female-biased temperature,could lead to temperature-specific expression of aromatase and increased estrogen levels,which may further determine gonadal development in Reeves' turtle.These findings provide insights into the genetic mechanisms underlying TSD. 展开更多
关键词 Reeves' turtle Mauremys reevesii temperature-dependent sex determination (TSD) cyp19a1 gene methylation
下载PDF
基于Python-turtle库的程序设计图例教学法与实践 被引量:2
20
作者 刘旭 马文彬 吴茜 《计算机教育》 2020年第3期101-104,108,共5页
针对目前程序设计类课程对控制结构的讲解存在的问题,分析根本原因,提出基于Pythonturtle库的程序设计图例教学法,列举顺序结构、选择结构和循环结构3种控制结构,阐述图例教学法的教学要点。
关键词 PYTHON语言 turtle 程序设计 控制语句
下载PDF
上一页 1 2 56 下一页 到第
使用帮助 返回顶部