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Extreme Value Statistics and the Lorenz Attractor

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Extreme Value Statistics and the Lorenz Attractor

Response of tropical avifauna to visitor recreational disturbances: a case study from the Sinharaja world Heritage Forest, Sri Lanka

第二十三届中国控制会议

作者： S.Sugathadasa Douglas A.Smith Kishore C.Mehta w.p.dayawansa Department of Mathematics and Statistics Texas Tech University Lubbock TX 79409USA Department of Civil Engineering and the wind Science and Engineering Research Center Texas Tech University Lubbock TX 79409USA Department of Civil Engineering and the wind Science and Engineering Research Center Texas Tech University Lubbock TX 79409USA Department of Mathematics and Statistics Texas Tech University Lubbock TX 79409-1042USA

＜正＞ Extreme value statistics is anticipated to play an increasingly important role in systems theory research. There are two reasons behind this;one is that the number of actuators and sensors in systems envisioned today, e.g. micro-electromechanical arrays and nanotechnology, biomimetic control, molecular computing, etc. will contain hundreds of thousands of actuators and sensors, and the other is the increasing attention paid by systems theorists to natural and environmental systems in which one needs to forecast extremes in wind speed, temperature, rain fall etc. for safe and reliable design. Theory of extreme value statistics is based upon several rather stringent assumptions. An open question is whether physical models such as wind, rainfall etc. satisfy such assumptions. Since there does not appear to be any way to answer this question is a direct way, here we attempt to device an indirect, and somewhat anecdotal, way to test the hypothesis that one may make long term forecasts from medium term data series. we choose the Lorenz system as a simple model to test the predictive capability of extreme value statistics. This choice is motivated by the fact that the Lorenz model is often quoted as an example of a system that has the same qualitative characteristics as the weather patterns. Our main conclusion is that one must be a bit circumspect in using this methodology to make long term forecasts.

关键词： Extreme value statistics large scale systems Lorenz System

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Chinese Birds 2016年第3期7卷 142-154页

作者： Nilusha S.Alwis priyan perera Nihal p.dayawansa Department of Forestry and Environmental Science University of Sri Jayewardenepura Department of Zoology University of Colombo

Background: we investigated the impact of human recreational disturbances on the distribution of birds along a popular nature trail in Sinhararja world Heritage Forest, Sri Lanka. It was hypothesized that visual and noise stimuli caused by the presence of humans affect the distribution of avifauna associated with this nature ***: Nine circular plots of 25 m fixed-radius laid along the trail(0 m), and 18 plots laid perpendicular to the trail at 75 and 150 m intervals, were studied from March 2013 to January 2014. The degree of human recreational disturbances was assessed in terms of visitor group size(visual disturbance) and their noise level(sound disturbance). These disturbances were categorized along a four-point scale(no human disturbance, low, medium and high disturbance). The relationship between disturbance levels and the abundance of birds was statistically ***: ANOVA results revealed that the abundance of birds differed significantly under various intensities of recreational disturbances at each distance level. A significant negative correlation between abundance of birds and intensity of disturbance at 0 m distance suggests an avoidance of edge habitats by birds in the presence of humans. Abundance of birds increased at the 75 and 150 m distance levels with increasing disturbances occurring at the trail. Significant negative correlations were further observed between disturbance level and the abundance of birds in ground/understory and sub-canopy vertical strata of the forest at 0 m ***: Under high levels of recreational disturbance occurring at this trail, the abundance of birds near the trail declined significantly, while bird abundance in the interior of the forest increased. The sensitivity of individual bird species to visitor disturbances varied with the vertical stratum of the forest they usually occupy. Birds occupying the ground, understory and sub-canopy are particularly sensitive to recreational disturbances

关键词： Recreational disturbances Ecotourism Tropical birds Sinharaja world Heritage Forest Habituation

Approximation of a switched linear system by a nonswitched homogeneous polynomial system

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控制理论与应用（英文版） 2006年第1期4卷 3-10页

作者： p. C. pERERA w. p. dayawansa Department of Engineering Mathematics University of peradeniya peradeniya Sri Lanka Department of Mathematics and Statistics Texas Tech University Lubbock Texas 79409 U.S.A.

It is shown that given a switched linear control system which satisfy the controllability rank condition, it is possible to construct a non-switched homogenous polynomial control system in such a way that the trajecto... 详细信息

关键词： Switching systems Approximation of trajectories Homogeneous systems Controllability

Simultaneous Erb's and Klumpke's palsy: Case report

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world Journal of Clinical Cases 2015年第12期3卷 984-987页

作者： Ashley Dawson Eliana Vasquez David Garrett Jr Frank S Harris Ibrahim M El Nihum Samantha dayawansa Jason H Huang Soren Singel Faculty of Medicine Texas A and M University Department of Neurosurgery Baylor Scott and White Health Care

Mapping nerve deficits during a physical exam after trauma to the upper extremity can help determine not only if the brachial plexus was injured but also which nerve roots were involved. A 28-year-old male presented with simultaneous signs and symptoms of Erb's(C5) and Klumpke's(C8, T1) palsy, with sparing of the C6 and C7 roots. The patient presented several months ago to his local emergency room with shortness of breath, which was determined to be caused by left diaphragmatic paralysis through clinical and radiographical evidence. However, the etiology of the current nerve dysfunction in the upper extremity remained unknown. with persistent questioning and establishing the patient's trust in the caregivers, it was revealed that the patient had attempted suicidal hanging. we describe the clinical features and the likely mechanism of injury leading to this previously unreported combination of brachial plexus injuries. The unique injuries to this patient's brachial plexus can be explained by the sequence of events during the attempted suicidal hanging. The upper brachial plexus was injured during the initial moments where the neck was excessively stretched and the lower brachial plexus was injured due to the patient reaching up and holding himself by his arm for an extended period of time.

关键词： Erb’s palsy Klumpke’s palsy Hanging injury

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索管节点应力集中系数的足尺模型试验研究

钢结构 2009年第2期24卷 85-85,52页

作者： F.R.Mashiri p.dayawansa

对4个索管节点进行足尺模型试验,确定索管节点的应力集中系数。在节点的内部和外部均安装了量表以测量焊缝脚部与根部的应力分布。在两种荷载下测量了应力集中系数,一种是沿着主索方向的拉、压力,另一种是垂直支撑上沿着斜撑反作用力方... 详细信息

对4个索管节点进行足尺模型试验,确定索管节点的应力集中系数。在节点的内部和外部均安装了量表以测量焊缝脚部与根部的应力分布。在两种荷载下测量了应力集中系数,一种是沿着主索方向的拉、压力,另一种是垂直支撑上沿着斜撑反作用力方向上的拉、压力。提出了焊缝焊脚和焊根与相应应力集中系数的关系。用硅痕技术和接触式量表测量的焊缝形状和焊根缺口,为将来的有限元模拟以及采用有效切口应力方法研究焊根的破坏提供参考。

关键词：应力集中系数管节点拉索疲劳

Stereotactic radiosurgery for haemorrhagic cerebral cavernous malformation:a multi-institutional,retrospective study

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Stroke & Vascular Neurology 2024年第3期9卷 221-229,I0130,I0131页

作者： Chloe Dumot Georgios Mantziaris Sam dayawansa Zhiyuan Xu Stylianos pikis Selcuk peker Yavuz Samanci Gokce D Ardor Ahmed M Nabeel wael A Reda Sameh R Tawadros Khaled Abdelkarim Amr M N El-Shehaby Reem M Emad Eldin Ahmed H Elazzazi Nuria Martínez Moreno Roberto MartínezÁlvarez Roman Liscak Jaromir May David Mathieu Jean-Nicolas Tourigny Manjul Tripathi Akshay Rajput Narendra Kumar Rupinder Kaur piero picozzi Andrea Franzini Herwin Speckter wenceslao Hernandez Anderson Brito Ronald E warnick Juan Alzate Douglas Kondziolka Greg N Bowden Samir patel Jason Sheehan Department of Neurological Surgery Hospices Civils de LyonLyonFrance Department of Neurological Surgery University of VirginiaCharlottesvilleVirginiaUSA Department of Neurosurgery Koc University School of MedicineIstanbulTurkey Gamma-knife Center Nasser institute HospitalCairoEgypt Neurosurgery Department Benha UniversityBenhaEgypt Departments of Neurosurgery Ain Shams UniversityCairoEgypt Department of Clinical Oncology Ain Shams UniversityCairoEgypt Department of Radiation Oncology National Cancer InstituteCairo UniversityGizaEgypt Faculty of Medicine Extended Modular ProgramAin Shams UniversityCairoEgypt Department of Radiosurgery Rúber Internacional HospitalMadridSpain Department of Stereotactic and Radiation Neurosurgery Na Homolce HospitalPragueCzech Republic Neurosurgery Centre de recherche du CHUSUniversitéde SherbrookeSherbrookeQuebecCanada Neurosurgery PGIMERChandigarhChandigarhIndia Radiation Therapy PGIMERChandigarhChandigarhIndia Neurosurgery IRCCS Istituto Clinico HumanitasRozzanoMilanItaly Dominican Gamma Knife Center and Radiology Department CEDIMATSanto DomingoDominican Republic Gamma Knife Center Mayfield ClinicThe Jewish Hospital-Mercy HealthCincinnatiOhioUSA Neurosurgery NYU Langone HealthNew YorkNew YorkUSA Neurosurgery University of AlbertaEdmontonAlbertaCanada Division of Radiation Oncology Department of OncologyUniversity of AlbertaEdmontonAlbertaCanada

Background Cerebral cavernous malformations(CCMs)frequently manifest with *** radiosurgery(SRS)has been employed for CCM not suitable for *** effect on reducing haemorrhage risk is still *** aim of this study was to expand on the safety and efficacy of SRS for haemorrhagic *** This retrospective multicentric study included CCM with at least one haemorrhage treated with single-session *** annual haemorrhagic rate(AHR)was calculated before and after *** event analysis and Cox regression were used to evaluate factors associated with *** radiation effects(AREs)and occurrence of new neurological deficits were *** The study included 381 patients (median age:37.5 years(Q1–Q3:25.8–51.9))with 414 *** AHR from diagnosis to SRS excluding the first haemorrhage was 11.08 per 100 CCM-years and was reduced to 2.7 per 100 CCM-years after *** recurrent event analysis,SRS,HR 0.27(95%CI 0.17 to 0.44),pwas associated with a decreased risk of haemorrhage,and the presence of developmental venous anomaly(DVA)with an increased risk,HR 1.60(95%CI 1.07 to 2.40),p=*** cumulative risk of first haemorrhage after SRS was 9.4%(95%CI 6%to 12.6%)at 5 years and 15.6%(95%CI%9 to 21.8%)at 10 *** doses>13 Gy,HR 2.27(95%CI 1.20 to 4.32),p=0.012 and the presence of DVA,HR 2.08(95%CI 1.00 to 4.31),p=0.049 were factors associated with higher probability of post-SRS ***-SRS haemorrhage was symptomatic in 22 out of 381(5.8%)patients,presenting with transient(15/381)or permanent(7/381)neurological *** occurred in 11.1%(46/414)CCM and was responsible for transient neurological deficit in 3.9%(15/381)of the patients and permanent deficit in 1.1%(4/381)of the *** doses>13 Gy and CCM volume>0.7 cc were associated with increased risk of ARE.

关键词： doses haemorrhagic diagnosis