10,559 research outputs found

    MLD Relations of Pisot Substitution Tilings

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    We consider 1-dimensional, unimodular Pisot substitution tilings with three intervals, and discuss conditions under which pairs of such tilings are locally isomorhphic (LI), or mutually locally derivable (MDL). For this purpose, we regard the substitutions as homomorphisms of the underlying free group with three generators. Then, if two substitutions are conjugated by an inner automorphism of the free group, the two tilings are LI, and a conjugating outer automorphism between two substitutions can often be used to prove that the two tilings are MLD. We present several examples illustrating the different phenomena that can occur in this context. In particular, we show how two substitution tilings can be MLD even if their substitution matrices are not equal, but only conjugate in GL(n,Z)GL(n,\mathbb{Z}). We also illustrate how the (in our case fractal) windows of MLD tilings can be reconstructed from each other, and discuss how the conjugating group automorphism affects the substitution generating the window boundaries.Comment: Presented at Aperiodic'09 (Liverpool

    Empirical Analysis of Causes of Income Inequality: A Level Playing Field for Children at the Start of School Career

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    Numerous and countless factors have been theorized to be causes of inequality. This paper started with identifying the most important determinants of income inequality through theoretical research. Among the various theories of causes of inequality, I hypothesized creating a level playing for children at the very start of their career as students as an important determinant. In order to test the hypothesis that a level playing field is important to help fight inequality, a regression tailored for this question is created. I develop a regression model using the variable public expenditure on primary education as the variable to be tested while controlling for other important determinants of inequality including public expenditure per student on all stages of education, unemployment rate, GDP per capita, GDP growth, and governance indicator. The empirical model confirms theory that quality of primary education is highly beneficial for students. I conduct further theoretical research concerning ways to improve the quality of primary education and included them in policy recommendation section

    A discrete methodology for controlling the sign of curvature and torsion for NURBS

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    This paper develops a discrete methodology for approximating the so-called convex domain of a NURBS curve, namely the domain in the ambient space, where a user-specified control point is free to move so that the curvature and torsion retains its sign along the NURBS parametric domain of definition. The methodology provides a monotonic sequence of convex polyhedra, converging from the interior to the convex domain. If the latter is non-empty, a simple algorithm is proposed, that yields a sequence of polytopes converging uniformly to the restriction of the convex domain to any user-specified bounding box. The algorithm is illustrated for a pair of planar and a spatial Bézier configuration

    Intractable Haematuria in Pregnancy: Challenges of Management Case Report and Review of Literature

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    Background: Intractable haematuria is a life threatening and challenging urological emergency. It is more so when it occurs in pregnancy as the lives of both mother and baby are at risk. The safety in pregnancy of most agents or methods used in treatment of this condition is unknown.Materials & methods: A 24 years old pregnant woman at 29 weeks gestation complained of total painless haematuria for days. Ultrasound scan revealed a bladder mass and a viable intrauterine gestation. She was admitted and managed with continuous saline irrigation of the bladder, and repeated blood transfusions as well as fetal monitoring. After 4 weeks, absent fetal heart tone was noticed. She went into spontaneous labour and was delivered of a fresh still born. She then had bladder irrigation with 1% alum solution. The bleeding stopped within 48 hours of treatment and she was discharged 72 hours later.Conclusion: Intravesical alum irrigation is an effective method of treatment, its safety profile in pregnancy is unknown thus more studies in this regard are needed to prevent adverse maternal or perinatal outcomes

    Dynamic Triaxial and Vibratory In-Situ Behavior of Cohesive Soil

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    In-situ and laboratory shear modulus data are presented and compared. In-situ tests included the cross-hole seismic survey at a stiff marl site, while laboratory tests included the cyclic triaxial test on undisturbed specimens obtained from the same site. The cyclic triaxial device presented in this investigation has been developed and improved so that the reliable response of soil can be measured directly from the specimen over a large range of strain (from 10-6 to 10-2 ). A series of cyclic triaxial tests were performed under stress controlled condition over a range of frequency from 0,5 to 10 Hz on marl samples consolidated anisotropically. Values of shear modulus and damping ration determined for shearing strain amplitude between 10-6 and 10-2 and compared with published results proposed by Seed and Idriss (1970) and Hardin and Drnevich (1972). At low strains, the shear modulus values measured by in-situ and laboratory methods were in a good agreement, but the values from the Hardin-Black\u27s equation were underestimated. The influence of consolidation stress, frequency, and number of load cycles on the shear modulus have also been investigated

    Case Report - Analgesic nephropathy as a cause of end‑stage renal disease in a 55 year‑old Nigerian

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    Analgesic nephropathy is a subtle but significant cause of chronic renal failure. There is paucity of data on analgesic nephropathy in Nigeria. This case presentation is to highlight the need to have high index of suspicion in patients at risk of developing analgesic nephropathy. In March 2009 a 55‑year‑old businessman was referred to the renal unit on account of azotemia by the hematologist who had hitherto managed the patient as a case of refractory anemia. The patient had osteoarthritis for over 10 years and was managed with several analgesic drugs over the same period. He was found to have features suggestive of analgesic nephropathy and had end‑stage renal disease. He was commenced on appropriate therapy, and he had a live related kidney transplant six months later. Analgesic nephropathy is preventable and morbidity/mortality can be remarkably reduced with appropriate and prompt intervention

    Penerapan Infrared Remote Control Dalam Mengoperasikan Aplikasi Pada Sistem Operasi Windows Xp

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    In the 20th century the technology associated with the collection. Processing and distribution of information have evolved considerably . Other technologies are experiencing rapid growth is utilizing the computer as a device that is versatile and can be especially helpful in facilitating human work .The development of computers from generation to generation until today more optimal performance, such as one of the advantages of multimedia, can steady MP3 songs. The development of electronic technology raises human tendency to make activities easier and practical , one of which is a wireless controller . On a computer that has a standard multimedia device , the operation should be done with a keyboard and mouse on the computer, so the user must always close and interact with both the input device. Because each piece of equipment has a different coding standards so users who use several different tools brand using multiple controllers. Based on the above introduction, the authors examine how to operate the application on the Windows XP operating system by using the infrared remote control

    Effect Of Seasonal Rainfall And Other Environmental Changes, On Snail Density And Infection Rates With Schistosoma mansoni Fifteen Years After The Last Snails\' Study In Kigungu, Entebbe, Uganda

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    Background: The last study on snail population density in relation to rainfall pattern in Kigungu canoe landing and recreational sites on Lake Victoria shore was earlier carried out about fifteen years ago. This study also reviewed the influence of other environmental factors on the snails\' infection rate. Objective: To reassess the density dynamic of Biomphalaria (B) choanomphala and Biomphalaria (B) pfeifferi, which act as the intermediate host for S. mansoni and Bulinus (B) globosus, and Bulinus (B) tropicus, which act as intermediate host for S. haematobium. Design: Retrospective study. Setting: Busy canoe landing sites along Lake Victoria in Kigungu fishing village were selected for the snail sampling. Results: Nine thousand one hundred and ninety four B. choanomphala were collected over the study period. The numbers of B. choanomphala collected in each year was 4742 (51.6%) and 4452 (48.4%) in 2004 and 2005 respectively. Of the 4742 B.Choanomphala collected in 2004, 82 (1.7%) shed human cercariae and 329 (6.7%) shed non-human cercariae. Whereas in 2005, out of 4452 B. choanomphala collected 302 (6.85%) shed non-human cercariae and 82 (1.8%) shed human cercariae. Similarly, 4173 B. pfeifferi were also collected in the same period. Out of which 2224 (53.3%) were collected in 2004 and 1949 (46.7%) in 2005. For B. pfeifferi, 42 (1.9%) out of 2224 snails collected in 2004 shed human cercariae and 246 (11.1%) shed non-human cercariae. While in 2005, 33 out of 1949 snails (1.7%) shed human cercariae and 159 (8.2%) shed non-human cercariae. Other snails of medical importance collected included 292 B. globosus and 3094 B. tropicus. None of the Bulinus spp. collected shed any human cercariae but 37 (2.1%) and 30 (2.3%) B. tropicus shed non-human cercariae in 2004 and 2005 respectively. In 2004 and 2005, the area received, 1729mm and 1959mm of rainfall respectively. The mean rainfall during the year was 144.05 mm and 163.3 mm in 2004 and 2005 respectively. There was a negative correlation between rainfalls and snail density dynamic. Conclusion: We have found in this study that in spite of the bush clearing of the papyrus swamps which originally was the major habitats for B. choanomphala, B. pfeifferi and the Bulinus spp the intermediate host for schistosome at all canoe landing sites at Kigungu, these snails are still present. Moreover, that their population density dynamic and infection rate are inversely proportional to the rainfall pattern. East African Medical Journal Vol. 85 (11) 2008: pp. 556-56

    Pollution des eaux superficielles et des nappes en milieu urbain : cas de la zone industrielle de Douala-Bassa (Cameroun)

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    Une étude a été menée dans la zone industrielle de Douala-Bassa afin d'évaluer l'ampleur de la pollution des cours d'eau et des nappes superficielles et de prédire la vulnérabilité de ces dernières. L'étude est basée sur l'analyse des eaux issues de deux campagnes de terrain portant chacune sur 7 prélèvements dans les eaux de surface et 8 dans les eaux souterraines. Outre les analyses physico-chimiques de base, la particularité de l'étude a porté sur la caractérisation de la matière organique et la dynamique de métaux lourds, notamment le plomb, lenickel et le cuivre. Les résultats montrent que les eaux de surface sont neutres (pH 6,2), peu minéralisées (conductivité moyenne 262 mS/cm) et peu turbides (7 NTU) à l'amont. Elles s'enrichissent ensuite dans leréseau où elles deviennent acides (pH 5,8), plus minéralisées (623 à 818 mS/cm) suite aux apports générés par les activités industrielles et domestiques. Les eaux de surface sont polluées (carbonique organique total, 13,0 mg/l ; turbidité 168 NTU). Une source potentielle de pollution au nickel et en matière organique est observée dans les eaux souterraines qui compromet l'exploitation durable de cette ressource en eau
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