307 research outputs found

    Classification of images of wheat, ryegrass and brome grass species at early growth stages using principal component analysis

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    Wheat is one of the most important crops in Australia, and the identification of young plants is an important step towards developing an automated system for monitoring crop establishment and also for differentiating crop from weeds. In this paper, a framework to differentiate early narrow-leaf wheat from two common weeds from their digital images is developed. A combination of colour, texture and shape features is used. These features are reduced to three descriptors using Principal Component Analysis. The three components provide an effective and significant means for distinguishing the three grasses. Further analysis enables threshold levels to be set for the discrimination of the plant species. The PCA model was evaluated on an independent data set of plants and the results show accuracy of 88% and 85% in the differentiation of ryegrass and brome grass from wheat, respectively. The outcomes of this study can be integrated into new knowledge in developing computer vision systems used in automated weed management

    Role of graft oversizing in the fixation strength of barbed endovascular grafts

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    PurposeThe role of endovascular graft oversizing on risk of distal graft migration following endovascular aneurysm repair for abdominal aortic aneurysm is poorly understood. A controlled in vitro investigation of the role of oversizing in graft-aorta attachment strength for endovascular grafts (EVGs) with barbs was performed.MethodsBarbed stent grafts (N = 20) with controlled graft oversizing varying from 4-45% were fabricated while maintaining other design variables unchanged. A flow loop with physiological flow characteristics and a biosynthetic aortic aneurysm phantom (synthetic aneurysm model with a bovine aortic neck) were developed. The stent grafts were deployed into the aortic neck of the bio-synthetic aortic aneurysm phantom under realistic flow conditions. Computed tomography imaging of the graft-aorta complex was used to document attachment characteristics such as graft apposition, number of barbs penetrated, and penetration depth and angle. The strength of graft attachment to the aortic neck was assessed using mechanical pullout testing. Stent grafts were categorized into four groups based on oversizing: 4-10%; 11-20%; 21-30%; and greater than 30% oversizing.ResultsPullout force, a measure of post-deployment fixation strength was not different between 4-10% (6.23 ± 1.90 N), 11-20% (6.25 ± 1.84 N) and 20-30% (5.85 ± 1.89 N) groups, but significantly lower for the group with greater than 30% oversizing (3.67 ± 1.41 N). Increasing oversizing caused a proportional decrease in the number of barbs penetrating the aortic wall (correlation = −0.83). Of the 14 barbs available in the stent graft, 89% of the barbs (12.5 of 14 on average) penetrated the aortic wall in the 4-10% oversizing group while only 38% (5.25 of 14) did for the greater than 30% group (P < .001). Also, the stent grafts with greater than 30% oversizing showed significantly poorer apposition characteristics such as eccentric compression or folding of the graft perimeter. The number and depth of barb penetration were found to be positively correlated to pullout force.ConclusionGreater than 30% graft oversizing affects both barb penetration and graft apposition adversely resulting in a low pullout force in this in vitro model. Barbed stent grafts with excessive oversizing are likely to result in poor fixation and increased risk of migration.Clinical RelevanceMigration of the endovascular grafts in abdominal aortic aneurysm (AAA) patients continues to be a cause of long-term complication in patients. This study is an assessment of the role of graft oversizing, a key variable chosen by the physician, on the fixation strength of these implants to the parent aorta. The findings suggest caution when choosing stent grafts that are excessively oversized

    Morphometric and meristic study of Garra rufa populations in Tigris and Persian Gulf Basins

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    This study was conducted to determine morphometric and meristic characteristics of Garra rufa in 13 stations of Tigris and Persian Gulf basins. We caught 310 specimens during the year 2007-2008 using electro-shocker and sachok. Univariate analysis of variance (ANOVA) and principal component analysis were conducted and the ANOVA revealed significant differences in 28 morphometric and 9 meristic factors (P<0.05). Factor analysis showed that G. rufa of thirteen stations had 48.855% changes in 3 factors of the first morphometric characters (pectoral fin length, ventral fin length, depth of anal fin) and 71/611% changes in 3 factors of the first meristic characters (lateral line scales , circum peduncle scales, predorsal scales). Plotting the first and second principal component morphometric and meristic characters showed that the Mond River population was separated from the others but the other populations were overlapping with each other in the characteristics studied

    Obstructive sleep apnea syndrome and non-arteritic anterior ischemic optic neuropathy: A case control study

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    Background: Sleep apnea is temporary cessation or absence of breathing during sleep. Significant increase in blood pressure is clinically seen in apneic episodes. The aim of this study was to examine sleep apnea syndrome as a risk factor for non- arthritic anterior ischemic optic neuropathy (NAION) in a case control study. Methods: Nineteen NAION patients (9 men and 10 women) and 31 age and sex matched control participants (18 men and 13 women) were evaluated for obstructive sleep apnea syndrome (OSAS). Full night polysomnography was performed and proportion of OSAS was compared between the NAION patients and the control group. Other risk factors for NAION such as hypertension, diabetes, hyperlipidemia, ischemic heart disease and tobacco consumption were also evaluated. Chi square test and independent samples t-test were used for statistical analysis. Results: OF the 19 NAION patients, 18 (95) had OSAS, and of the control group 13 (41.9) had OSAS. The frequency of OSAS was significantly higher among NAION patients compared to the controls (p < 0.001). The Mean Respiratory Disturbance Index (RDI) was 37.65/h SD = 37.61/h in NAION patients and it was 15.05/h SD = 11.97/h (p = 0.018) in controls. The frequency of diabetes and hypertension was significantly higher in the NAION patients than in controls. Conclusion: based on the results of this study, it seems that there is an association between NAION and OSAS

    Minimally invasive treatments for lower urinary tract symptoms in men with benign prostatic hyperplasia : a network metaanalysis (Protocol)

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    A C K N O W L E D G E M E N T S We are very grateful to Cochrane Urology, especially the Managing Editor Robert Lane, as well as Cochrane Urology Korea for supporting this review. Furthermore, we are grateful to Gretchen Kuntz for revising and providing feedback on the search strategies. We also thank Marco Blanker, Sevann Helo, and Murad Mohammad for their peer-review input of the protocol. S O U R C E S O F S U P P O R T Internal sources • Instituto Universitario Hospital Italiano, Argentina Salary support for Juan Franco, Luis Garegnani, Camila Micalea Escobar Liquitay • Department of Urology, Yonsei University Wonju College of Medicine, Korea, South Salary support for Jae Hung Jung • Minneapolis VA Health Care System, USA Salary support for Philipp Dahm • Department of Urology, University of Minnesota, USA Support in kind for Philipp DahmPeer reviewedPublisher PD

    Minimally invasive treatments for benign prostatic hyperplasia : a Cochrane network meta-analysis

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    Acknowledgements This project was funded by the National Institute for Health Research (NIHR) [Cochrane Incentive Award (NIHR130819)]. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. We are very grateful to Cochrane Urology, especially Managing Editor Robert Lane, as well as Cochrane Urology Korea, for supporting this review. We are also grateful for the constructive feedback from the Cancer Network and the Methods Support Unit. We also thank Gretchen Kuntz for revising and providing feedback on the search strategies; Marco Blanker, Sevann Helo, and Murad Mohammad for their peer review input of the protocol; Dominik Abt, Bilal Chughtai, and Ahmed Higazy for providing details on the outcomes of their trials, for them to be incorporated accurately in our review; Marc Sapoval, Deepak Agarwal, Cameron Alexander, Harris Foster, and Mitchell Humphreys for their peer review input of the review. Juan Víctor Ariel Franco is a PhD candidate in the Programme of Methodology of Biomedical Research and Public Health, Universitat Autònoma de Barcelona (Spain)Peer reviewedPostprin

    Accurate inference of shoot biomass from high-throughput images of cereal plants

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    Extent: 11p.With the establishment of advanced technology facilities for high throughput plant phenotyping, the problem of estimating plant biomass of individual plants from their two dimensional images is becoming increasingly important. The approach predominantly cited in literature is to estimate the biomass of a plant as a linear function of the projected shoot area of plants in the images. However, the estimation error from this model, which is solely a function of projected shoot area, is large, prohibiting accurate estimation of the biomass of plants, particularly for the salt-stressed plants. In this paper, we propose a method based on plant specific weight for improving the accuracy of the linear model and reducing the estimation bias (the difference between actual shoot dry weight and the value of the shoot dry weight estimated with a predictive model). For the proposed method in this study, we modeled the plant shoot dry weight as a function of plant area and plant age. The data used for developing our model and comparing the results with the linear model were collected from a completely randomized block design experiment. A total of 320 plants from two bread wheat varieties were grown in a supported hydroponics system in a greenhouse. The plants were exposed to two levels of hydroponic salt treatments (NaCl at 0 and 100 mM) for 6 weeks. Five harvests were carried out. Each time 64 randomly selected plants were imaged and then harvested to measure the shoot fresh weight and shoot dry weight. The results of statistical analysis showed that with our proposed method, most of the observed variance can be explained, and moreover only a small difference between actual and estimated shoot dry weight was obtained. The low estimation bias indicates that our proposed method can be used to estimate biomass of individual plants regardless of what variety the plant is and what salt treatment has been applied. We validated this model on an independent set of barley data. The technique presented in this paper may extend to other plants and types of stresses.Mahmood R Golzarian, Ross A Frick, Karthika Rajendran, Bettina Berger, Stuart Roy, Mark Tester and Desmond S Lu

    Percutaneous Transabdominal Approach for the Treatment of Endoleaks after Endovascular Repair of Infrarenal Abdominal Aortic Aneurysm

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    OBJECTIVE: The purpose of this study was to evaluate the technical feasibility and clinical efficacy of percutaneous transabdominal treatment of endoleaks after endovascular aneurysm repair. MATERIALS AND METHODS: Between 2000 and 2007, six patients with type I (n = 4) or II (n = 2) endoleaks were treated by the percutaneous transabdominal approach using embolization with N-butyl cyanoacrylate with or without coils. Five patients underwent a single session and one patient had two sessions of embolization. The median time between aneurysm repair and endoleak treatment was 25.5 months (range: 0-84 months). Follow-up CT images were evaluated for changes in the size and shape of the aneurysm sac and presence or resolution of endoleaks. The median follow-up after endoleak treatment was 16.4 months (range: 0-37 months) RESULTS: Technical success was achieved in all six patients. Clinical success was achieved in four patients with complete resolution of the endoleak confirmed by follow-up CT. Clinical failure was observed in two patients. One eventually underwent surgical conversion, and the other was lost to follow-up. There were no procedure-related complications. CONCLUSION: The percutaneous transabdominal approach for the treatment of type I or II endoleaks, after endovascular aneurysm repair, is an alternative method when conventional endovascular methods have failedope

    Uterine Fibroid Embolisation for Symptomatic Uterine Fibroids: A Survey of Clinical Practice in Europe

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    Item does not contain fulltextPURPOSE: To assess current uterine fibroid embolisation (UFE) practice in European countries and determine the clinical environment for UFE in different hospitals. MATERIAL AND METHODS: In May 2009, an invitation for an online survey was sent by e-mail to all members of the Cardiovascular and Interventional Radiologic Society of Europe, representing a total number of 1,250 different candidate European treatment centres. The survey covered 21 questions concerning local UFE practice. RESULTS: A total of 282 respondents completed the questionnaire. Fifteen questionnaires were excluded because they were doubles from centres that had already returned a questionnaire. The response rate was 267 of 1,250 centres (21.4%). Ninety-four respondents (33%) did not perform UFE and were excluded, and six centres were excluded because demographic data were missing. The remaining 167 respondents from different UFE centres were included in the study. Twenty-six percent of the respondents were from the United Kingdom (n = 43); 16% were from Germany (n = 27); 11% were from France (n = 18); and the remaining 47% (n = 79) were from other European countries. Most centres (48%, n = 80) had 5 to 10 years experience with UFE and performed 10 to 50 procedures annually (53% [n = 88]) of respondents). Additional demographic data, as well as specific data on referral of patients, UFE techniques used, and periprocedural and postprocedural, care will be provided. CONCLUSION: Although UFE as an alternative treatment for hysterectomy or myomectomy is widespread in Europe, its impact on the management of the patient with symptomatic fibroids seems, according to the overall numbers of UFE procedures, somewhat disappointing. Multiple factors might be responsible for this observation
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