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Habitat structure and invertebrate assemblages on stream stones: A multivariate view from the riffle
Abstract Highly structured habitats, those with complex or heterogeneous physical structure, commonly contain more species than simply structured ones. However, tests of this relationship have been hampered by habitat-specific definitions and measurements of habitat structure and, in stream studies, by insufficient information on spatial variation in faunal abundances. We sampled the fauna of 90 stones collected from an order 4 section of the Taggerty and Steavenson Rivers, southeastern Australia. The spatially nested sampling design encompassed three spatial scales (sites within the same stream order, riffles at the same site and groups of stones within the same riffle) but no temporal replication, as we were only able to sample once. Habitat structure of stones was quantified by measuring the amount and type of epilithon on stones, together with stone shapes, sizes, textures and surface complexities. For the latter two attributes, we used a new method, involving image analysis, which can be used to quantify habitat structure in comparable ways in other systems. Species richness (S) was related to some measures of habitat structure, being higher on stones with a rough texture and weakly related to the amount of epilithon present. Total numbers of individuals (N) were also higher on rough stones, and faunal composition (as quantified by hybrid multidimensional scaling) was related to abundance of epilithon. However, flow environments, as quantified by water velocities and depths, were also related to faunal composition. Riffles varied in both faunal densities and near-bed flow environment, but not in any consistent way. Such variability means that individual riffles cannot be reasonably used to ‘represent’ stream sections or orders, an assumption commonly made in stream studies. Neglect of such issues has also resulted in poor conceptual integration between large- and small-scale studies in stream ecology. 相似文献
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Sidney Horenstein 《Evolution》2008,1(4):520-530
Cities large and small have a treasure trove of building stones both local as well as imported from various regions of the
country as well as foreign sources. Many of them contain fossils which are easily available for teachers to utilize for class
field trips. For some areas guidebooks exist which are listed in the attached appendix. Even for localities where no guidebook
exists these published guides can be helpful especially if they are illustrated. Field trips are a useful learning tool and
teachers are encouraged to create various lesson plans utilizing this generally unrecognized resource. 相似文献
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目的:总结一期行微通道经皮肾镜碎石术(microchannel percutaneous nephrolithotripsy,m PCNL)治疗上尿路感染性结石合并尿培养为耐碳青霉烯铜绿假单胞菌(carbapenem resistant pseudomonas aeruginosa,CRPA)的经验。方法:选择我院收治两例左肾结石合并尿培养为CRPA的患者,经积极抗感染治疗后,病例一行左侧经皮肾镜碎石术,病例二先行右肾穿刺造瘘术成功后行左侧经皮肾镜碎石术,观察分析两例患者术后结石清除情况,术中术后出现发热、腰痛、大出血、尿路损伤及肾功能衰竭等并发症情况。结果:两例患者术后复查双J管位置良好,结石基本清除;术中、术后均未出现发热、腰痛、大出血、尿路损伤及肾功能衰竭等并发症。结论:经过合适的围手术期处理,一期微通道经皮肾镜碎石术治疗感染性结石合并尿培养为耐药菌的患者是安全可行的。 相似文献
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Experiments on the colonization by macroinvertebrates of stones were performed in the Acheron and Toorongo Rivers, two upland rivers in south-eastern Australia. The three experiments were each about one month in duration. In the first experiment — Acheron I — and the third experiment — Toorongo — river stones were used. In the Acheron II experiment both river stones and quarry stones were used.The number of colonizing species with time in the Acheron I and Toorongo experiments fitted a logarithmic model with the colonization and elimination (extinction) rates both declining with time. The population densities of the total animals and of most of the common species fitted the power model (linear model on logarithmically transformed axes). In the Acheron II experiment the major difference between the colonization of river stones and quarry stones was the low numbers of scrapers on the quarry stones. The colonization of the stones in Acheron I and Toorongo by the various functional feeding groups is described. The colonization of stones in streams is a rapid process suggesting that the stream stone assemblage has a high resilience — an attribute of deterministic communities. 相似文献
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目的探讨钬激光在胆总管下段嵌顿性结石手术中的应用价值。方法通过腹腔镜下胆道镜工作通道,应用钬激光,功率为0.6—0.8J/10Hz,直径为200um光导纤维,在直视下接触结石,将嵌顿结石击碎后注水冲出,或用取石篮套出。结果11例均取石碎石成功,手术时间75—205min,平均95.5min,出血80—130ml,平均89.4ml。平均住院8.2d。术后无胆道出血,胆漏。术后2W照影无结石残留,胆总管下段通畅无胆道狭窄。术后肝功能2W恢复正常6例,5例1月均恢复正常。随访3—6月未见结石复发。结论钬激光治疗胆总管下段嵌顿结石,具有创伤小、恢复快、碎石确切、操作容易、安全有效等优点,为治疗复杂性胆总管结石开辟了一条新的治疗途径。 相似文献
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The Stone Brusher, a New Sampler for Submerged Epilithic Material in Shallow Streams and Lakes 总被引:1,自引:1,他引:0
The Stone Brusher is designed to take qualitative or semi-quantitative samples of material attached to stones at 7–50 cm depth
in running or stagnant waters. The epilithic material is dislodged from the stone surface with a rotating brush enclosed in
a chamber and the material is drawn up directly into the sample bottle with an air-cylinder. The operator takes a sample quickly
and without putting hands into the water. The sampling area is about 28 cm2. The sampler is made of plastic, stainless steel and aluminium and weighs 3.1 kg. The equipment is robust and easily handled
and it is constructed to meet the demand for standardized sampling for research and environmental monitoring and to improve
working conditions for sampling personnel. The equipment allows sampling from bedrock and large stones that cannot be lifted
from the bottom and it can be used for reliable sampling also in fast-flowing streams where the dislodged material is easily
flushed away. Using Near-Infrared Spectroscopy and diatom analyses, this new sampler is evaluated in comparison to the recognized
toothbrush method, which indicates that the Stone Brusher reduces sampling variability compared with the toothbrush method. 相似文献
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目的:考察内镜下逆行胰胆管造影术/十二指肠乳头括约肌切开术加腹腔镜胆囊切除术(endoscopic retrograde pancreatic angiography/endoscopic sphincterotomy-1 aparoscopic cholecystectomy,ERCP/EST-LC)对胆囊结石合并胆... 相似文献
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In this study, hard shell of apricot stones was selected from agricultural solid wastes to prepare effective and low cost adsorbent for the gold separation from gold-plating wastewater. Different adsorption parameters like adsorbent dose, particle size of activated carbon, pH and agitation speed of mixing on the gold adsorption were studied. The results showed that under the optimum operating conditions, more than 98% of gold was adsorbed onto activated carbon after only 3 h. The equilibrium adsorption data were well described by the Freundlich and Langmuir isotherms. Isotherms have been used to obtain thermodynamic parameters. Gold desorption studies were performed with aqueous solution mixture of sodium hydroxide and organic solvents at ambient temperatures. Quantitative recovery of gold ions is possible by this method. As hard shell of apricot stones is a discarded as waste from agricultural and food industries, the prepared activated carbon is expected to be an economical product for gold ion recovery from wastewater. 相似文献
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目的:探究金钱草颗粒对胆囊结石患者血清胆囊收缩素受体(CCK-A)和血管活性肠肽(VIP)含量的影响。方法:选取我院普
外科收治的胆囊结石患者218 例,采用双盲法将其分为实验组和对照组。对照组给予口服消炎利胆片和熊去氧胆酸片治疗,而实
验组给予金钱草颗粒和熊去氧胆酸片治疗。检测和比较两组患者治疗前后血清CCK-A 和VIP 含量以及胆囊结石数目、直径的变
化情况。结果:治疗后,两组患者胆囊结石数目、直径及血清VIP 含量均较治疗前显著减少或降低,且实验组显著低于对照组,差
异均具有统计学意义(P<0.05);而两组患者的血清CCK-A 含量均较治疗前明显升高,且实验组显著高于对照组,差异具有统计学
意义(P<0.05)。结论:金钱草颗粒可有效减少胆囊结石患者的结石大小和数目,这可能与其提高患者血清CCK-A 含量以及降低血
清VIP 含量有关。 相似文献
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目的:探讨内镜下逆行胰胆管造影术(ERCP)下塑料胆道支架引流术治疗复杂性胆总管结石的临床疗效和安全性。方法:回顾性分析2011年9月至2013年9月在我院经ERCP下胆道支架引流术治疗的32例复杂性胆总管结石患者的临床病例资料。结果:32例患者塑料胆道支架引流术全部成功,平均手术时间15-30分钟。术后,2例发生高淀粉酶血症,经禁食72小时后恢复正常,无穿孔、消化道大出血等ERCP严重并发症发生。术后1周,患者腹痛、发热消失,转氨酶及胆红素水平明显下降,平均住院时间6-15天。3个月复查B超,发现结石缩小19例,结石碎裂1例,支架脱落1例。术后7天、术后3个月的肝功能指标与术前比较均显著改善,差异均有统计学意义(P0.05)。结论:ERCP下塑料胆道支架引流术是一种复杂性胆总管结石安全有效的治疗方法,具有创伤小、风险较低、操作时间短、患者易耐受及手术成功率高等优点。 相似文献
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刘功海吴世东曾国华欧长伟范翰文何小鹏 《现代生物医学进展》2012,12(4):704-706
目的:比较药物治疗与布比卡因局部阻滞治疗输尿管上段结石所致的肾绞痛的临床疗效。方法:选择输尿管结石患者共120例。随机分成药物治疗组(M组)与局部阻滞组(B组)各60例,其中药物治疗组采用杜冷丁加阿托品治疗,局部阻滞组采用布比卡因行痛区局部阻滞,两组年龄、性别均无统计学差异,比较两组患者治疗的总有效率、不良反应、镇痛起效时间、缓解时间等疗效指标。结果:局部阻滞组治疗的总有效率大于药物治疗组,不良反应也比药物治疗组少。疼痛起效时间及缓解时间,局部阻滞组均明显短于药物治疗组。结论:布比卡因局部阻滞治疗输尿管上段结石所致的肾绞痛临床疗效明显优于以杜冷丁加阿托品为代表的药物治疗。 相似文献
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William F. Gale 《Journal of phycology》1975,11(4):472-473
A bar clamp with a collecting cup attached was used to collect epilithic algae samples on stones 4–50 cm diam.; stones were sampled by wading in shallow water and by SCUBA diving in deep water. The collecting cup delimits the sampling area (a 22 mm diam. circle) for cleaning and protects it from cell loss and desiccation. On some stones, ultrasonic vibration removed large numbers of cells (up to 62% of the total) missed by scraping and brushing. 相似文献
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目的:观察分析经尿道前列腺电切(TURP)联合输尿管镜钬激光碎石术治疗前列腺增生症(BPH)合并膀胱结石的效果。方法:本组61例患者先行膀胱结石钬激光碎石,然后采用经尿道前列腺电切术(TURP)治疗前列腺增生症。结果:61例一次性治疗成功,术后结石无残留,排尿情况较前明显改善,IPSS评分均分由24.4分降到9.4分,最大尿流率由7.2 mL/s上升到19.5 mL/s。结论:钬激光碎石及TURP同期治疗前列腺增生合并膀胱结石是安全有效的方法。 相似文献
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PurposeThe classification of urinary stones is important prior to treatment because the treatments depend on three types of urinary stones, i.e., calcium, uric acid, and mixture stones. We have developed an automatic approach for the classification of urinary stones into the three types based on microcomputed tomography (micro-CT) images using a convolutional neural network (CNN).Materials and methodsThirty urinary stones from different patients were scanned in vitro using micro-CT (pixel size: 14.96 μm; slice thickness: 15 μm); a total of 2,430 images (micro-CT slices) were produced. The slices (227 × 227 pixels) were classified into the three categories based on their energy dispersive X-ray (EDX) spectra obtained via scanning electron microscopy (SEM). The images of urinary stones from each category were divided into three parts; 66%, 17%, and 17% of the dataset were assigned to the training, validation, and test datasets, respectively. The CNN model with 15 layers was assessed based on validation accuracy for the optimization of hyperparameters such as batch size, learning rate, and number of epochs with different optimizers. Then, the model with the optimized hyperparameters was evaluated for the test dataset to obtain classification accuracy and error.ResultsThe validation accuracy of the developed approach with CNN with optimized hyperparameters was 0.9852. The trained CNN model achieved a test accuracy of 0.9959 with a classification error of 1.2%.ConclusionsThe proposed automated CNN-based approach could successfully classify urinary stones into three types, namely calcium, uric acid, and mixture stones, using micro-CT images. 相似文献
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BackgroundEnvironmental lead (Pb) and cadmium (Cd) pollution has been considered a risk factor in the etiology of kidney stones. However, the association between Pb and Cd exposure and kidney stone incidence has yet to be determined.ObjectivesThis study aimed to determine a possible the association between kidney stones with Pb and Cd exposure (alone or combined) in a non-occupational population.MethodsPb and Cd contaminations in soil-plant system were determined by flame atomic absorption spectrophotometry. Health risk assessment of dietary Pb or Cd intake from rice and vegetables were calculated. Kidney stones were diagnosed with urinary tract ultrasonography. Urinary cadmium (UCd) and blood lead (BPb) levels were determined by graphite-furnace atomic absorption spectrometry. Multivariate logistic regression models were constructed.ResultsThe hazard indexes (HI) of Pb and Cd were 7.91 and 7.31. The odds ratio (OR) was 2.83 (95 %CI:1.38−5.77) in males with high BPb (BPb ≥ 100 μg/L), compared with those with low BPb (BPb<100 μg/L). Compared to those with low BPb and low UCd (BPb<100 μg/L and UCd<2 μg/g creatinine), the ORs were 2.58 (95 % CI:1.17−5.70) and 3.43 (95 % CI:1.21−9.16) in females and males with high BPb and high UCd (BPb ≥100 μg/L and UCd ≥2 μg/g creatinine), respectively. The OR was 3.16 (95 % CI:1.26−7.88) in males with high BPb and low UCd (BPb ≥ 100 μg/L and UCd <2 μg/g creatinine), compared to those with low BPb and low UCd.ConclusionsKidney stones incidence was increased by high Pb exposure in males, and by Pb and Cd co-exposure in males and females. 相似文献
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Bernardo T. Arriaza 《American journal of physical anthropology》1997,104(3):393-397
This study reports the findings of complete bilateral separation of the neural arch (spondylolysis) in 176 inhumations from the Hyatt Site, Tumon Bay, which is located on the west side of the island of Guam. Skeletons were excavated and analyzed by the Paul H. Rosendahl Inc. (PHRI) team in 1989–1990. The inhumations were associated with the pre-European Latte Period (circa 1,200–1,521 A.D.). This period was characterized by the use of large stone pillars, called latte sets, for the construction of houses. Of the 176 individuals, only 38 adult skeletons had complete spines, and 21% (8/38) of these had evidence of spondylolysis in their lumbar vertebrae, particularly in L-5. The age of the eight individuals range from 30 to 50 years. No children were found with spondylolysis. Of the males 29.4% (5/17) had spondylolysis, as did 14.3% (3/21) of the females. However, the difference between the sexes was not statistically significant. Though the sample is small, it is suggested that the high incidence of lumbar spondylolysis found in these ancient Chamorros was related to lower back traumatic events. The transport of latte stones, involving hyperextension and torque of the lower back, while dragging the stones, probably contributed to the development of microfractures in the spine and subsequent spondylolysis. If this hypothesis is correct, then both males and females appear to have been participants in an organized community labor force. It is predicted that similar frequencies of spondylolysis will be found at other Latte sites. Am J Phys Anthropol 104:393–397, 1997. © 1997 Wiley-Liss, Inc. 相似文献
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目的:探讨中国近10年胰管结石的流行病学特征和诊疗经验的Meta分析.方法:联合检索中国知网和维普数据库有关胰管结石的文章,提取文章内有关数据输入特定excel表格,然后分类计算人数、性另q比例、百分比,分析胰管结石的流行病学特征和诊治经验.结果:中国从2000.1.1至2010.7.1共报道1841例胰管结石,男女比例为2.16:1,有准确年龄及平均年龄报道1585例,平均年龄45.68岁,平均年龄在35~55岁之间占总病例数81.86%.12.66%病例分布在浙江,为各省最多,96.91%的病人有腹痛表现.胰管切开取石,胰管空肠Roux-en-Y吻合术是最主要的治疗手段.结论:胰管结石男性好发,以中青年为主.浙江省病例最多,胰管切开取石,胰管空肠Roux-en-Y吻合术为主要治疗手段. 相似文献
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A comparative study of four dredges used for sampling benthic macroinvertebrates in rivers 总被引:1,自引:0,他引:1
SUMMARY. After considering the large number of dredges described in the literature, four light-weight dredges were chosen for manual operation from a small boat or the bank: Irish triangular dredge, small Fast dredge, medium-sized and large Naturalist's dredges. The dredges were tested in a series of trials at three sites in two rivers. A stratified random sample (number of sampling units, n = 5) was taken at each site and the modal particle sizes at sites 1–3 were 1–2 mm (fine gravel), 64–128 mm (larger stones) and 128–256 mm, respectively. The dredges usually took a similar range of stone sizes at each site but the design of the Fast dredge excluded larger stones (>16 mm). The Irish dredge sometimes failed to operate correctly. Variations in the volume of substrata taken with each dredge were large, both between sampling units in the same sample and between samples. The latter differences were partially due to the increase in the modal size of the stones, especially between sites 1 and 2, the different sampling areas of the dredges and the depth of penetration into the substratum. Penetration depth was probably greatest for the two Naturalist's dredges, smaller for the Fast dredge and smallest for the Irish dredge. In field trials, the relative abundances of major taxa were similar for most dredges at each site; major exceptions were the Fast dredge at site 2 and the Irish dredge at site 3. There was a high variability between sampling units in the same sample and therefore a lack of precision in the estimates of the mean number of invertebrates per sample. Therefore, the dredges cannot be used as quantitative samplers for the estimation of population density. Their adequacy as qualitative samplers for the estimation of total number of taxa per sample varied considerably and maximum estimates of their efficiencies for a small sample (n= 5) were <40% for the Irish and Fast dredges, >57% for the medium-sized Naturalist's dredge and >76% for the large Naturalist's dredge. There was a clear relationship between the number of taxa and the number of invertebrates taken at each site and this relationship was well described by a power law with an exponent within the range 0.18–0.53. The number of sampling units in the sample had no significant effect on the power-law equations for each site. The power-law equation was very similar for most of the dredges at each site, the only major exception being the Fast dredge at site 1. The implications of this relationship are discussed. 相似文献