198 research outputs found
Modeling of Power Losses Caused by Hidden Tree-Related High Impedance Faults
The great majority of overhead distribution systems in urban and rural areas of countries such as Australia, Iran and etc., are in interfering with vegetation. This phenomena leads to high impedance faults (HIFs) which not produce enough fault current to be detectable and consequently causes electrical energy losses. In this paper, according to experimental data obtained from measurements, the effective factors in power losses caused by trees are studied and a new numerical model of power loss is presented so as to reflect the effects of environmental conditions and biological classification. The base of this method is according to Samuelson theory. In proposed algorithm, the impacts of species, short-term environmental conditions (temperature and humidity) and long-term environmental conditions (Seasonal variations in physiology) on the power loss estimation are fully considered. Experimental investigations on a real low voltage (380 V) and medium voltage (20 kV) distribution network verify the algorithm\u27s operation
[Formian 2 and a Formian Function for Processing Polyhedric Configurations]
The work began in October 1994 with the following objectives: (1) to produce an improved version of the programming language Formian; and (2) to create a means for computer aided handling of polyhedric configurations including the geodesic forms of all kinds. A new version of Formian, referred to as Formian 2, is being implemented to operate in the Windows 95 environment. It is an ideal tool for configuration management in a convenient and user-friendly manner. The second objective was achieved by creating a standard Formian function that allows convenient handling of all types of polyhedric configurations. In particular, the focus of attention is on polyhedric configurations that are of importance in architectural and structural engineering fields. The natural medium for processing of polyhedric configurations is a programming language that incorporates the concepts of 'formex algebra'. Formian is such a programming language in which the processing of polyhedric configurations can be carried out using the standard elements of the language. A description of this function is included in a chapter for a book entitled 'Beyond the Cube: the Architecture of space Frames and Polyhedra'. A copy of this chapter is appended
Dust-Charge Variation Effects on Dust ion Acoustic Shock Waves in Four Component Quantum Plasma
The behavior of nonlinear quantum dust ion acoustic (QDIA) shock waves in a collisionless, unmagnetized plasma consisting of inertialess quantum electrons and positrons, classical cold ions and stationary negatively charged dust grains with dust charge variation is investigated using quantum hydrodynamic (QHD) equations. The propagation of small amplitude QDIA shock waves is governed by Burgers equation. It is shown that the dust charge variation plays an important role in the formation of such QDIA shock structures. The dependence of the shock waves amplitude and thickness on the chemical potential is investigated. The present theory is applicable to analyze the formation of nonlinear structures at quantum scales in dense astrophysical objects
Molekyylinmallinnusohjelma
Työn tavoitteena on suunnitella ja toteuttaa käyttökelpoinen molekyylinmallinnus-ohjelma, jota voisi mahdollisesti hyödyntää koulujen kemianopetuksessa tavanomaisen oppimisen ohella. Projektin idea lähti tekijän omasta mielenkiinnosta aiheeseen, ja käyttötarpeen selvittäminen sekä mahdollinen käyttöönotto on tarkoitus aloittaa vasta työn päättymisen jälkeen.
Työn etenemiseen riitti teorian kannalta lukiossa opitut kemian sekä pitkän matematiikan taidot, joita jouduttiin kuitenkin kertaamaan internetlähteitä hyödyntäen. Ohjelma toteutettiin Unity-pelimoottorilla, joka on suunniteltu erilaisten ohjelmien helppoon tuottamiseen ja jonka käyttöönottokynnys on suhteellisen matala.
Työn ohjelmointipuolen hankaluudesta johtuen sen jää kesken, joten jatkokehitystä on tehtävä, ennen kuin ohjelman käyttöä voidaan harkita opetuksessa.The aim of the thesis was to design and implement a 3D molecule modelling application that could be used in schools to help visualize molecules alongside with the traditional teaching methods. It remains to be seen whether the program will actually see any use, as the marketing side of the project was intentionally left out of the thesis work and will be conducted on a later date.
For this thesis it was enough to know the basics of molecular chemistry and maths learned in high school, even though some rehearsing was necessary. The software was made using the Unity-engine, which is designed for easy developing of software. Its deployment has also been made simple, which helped in choosing it for this work.
Due to the difficulties encountered during the development process the application was not made to the point originally planned. Further development is however planned for it and is needed before it can be considered to be used for teaching in schools
Hemoglobin Q-Iran detected in family members from Northern Iran: a case report
<p>Abstract</p> <p>Introduction</p> <p>Hemoglobin Q-Iran (α75Asp→His) is an important member of the hemoglobin Q family, molecularly characterized by the replacement of aspartic acid by histidine. The first report of hemoglobin Q-Iran and the nomenclature of this hemoglobinopathy dates back to 1970. Iran is known as a country with a high prevalence of α- and β-thalassemia and different types of hemoglobinopathy. Many of these variants are yet to be identified as the practice of molecular laboratory techniques is limited in this part of the world. Applying such molecular methods, we report the first hemoglobin Q-Iran cases in Northern Iran.</p> <p>Case presentation</p> <p>An unusual band was detected in an isoelectric focusing test and cellulose acetate electrophoresis of a sample from a 22-year-old Iranian man from Mazandaran Province. Capillary zone electrophoresis analysis identified this band as hemoglobin Q. A similar band was also detected in his mother's electrophoresis (38 years, Iranian ethnicity). The cases underwent molecular investigation and the presence of a hemoglobin Q-Iran mutation was confirmed by the amplification refractory mutation system polymerase chain reaction method. Direct conventional sequencing revealed a single guanine to cytosine missense mutation (c.226G > C; <it>G</it>AC ><it>C</it>AC) at codon 75 in the α-globin gene in both cases.</p> <p>Conclusion</p> <p>The wide spectrum and high frequency of nondeletional α-globin mutations in Mazandaran Province is remarkable and seem to differ considerably from what has been found in Mediterranean populations. This short communication reports the first cases of patients with hemoglobin Q found in that region.</p
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Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
Background
The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk–outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk–outcome pairs, and new data on risk exposure levels and risk–outcome associations.
Methods
We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk–outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017.
Findings
In 2017, 34·1 million (95% uncertainty interval [UI] 33·3–35·0) deaths and 1·21 billion (1·14–1·28) DALYs were attributable to GBD risk factors. Globally, 61·0% (59·6–62·4) of deaths and 48·3% (46·3–50·2) of DALYs were attributed to the GBD 2017 risk factors. When ranked by risk-attributable DALYs, high systolic blood pressure (SBP) was the leading risk factor, accounting for 10·4 million (9·39–11·5) deaths and 218 million (198–237) DALYs, followed by smoking (7·10 million [6·83–7·37] deaths and 182 million [173–193] DALYs), high fasting plasma glucose (6·53 million [5·23–8·23] deaths and 171 million [144–201] DALYs), high body-mass index (BMI; 4·72 million [2·99–6·70] deaths and 148 million [98·6–202] DALYs), and short gestation for birthweight (1·43 million [1·36–1·51] deaths and 139 million [131–147] DALYs). In total, risk-attributable DALYs declined by 4·9% (3·3–6·5) between 2007 and 2017. In the absence of demographic changes (ie, population growth and ageing), changes in risk exposure and risk-deleted DALYs would have led to a 23·5% decline in DALYs during that period. Conversely, in the absence of changes in risk exposure and risk-deleted DALYs, demographic changes would have led to an 18·6% increase in DALYs during that period. The ratios of observed risk exposure levels to exposure levels expected based on SDI (O/E ratios) increased globally for unsafe drinking water and household air pollution between 1990 and 2017. This result suggests that development is occurring more rapidly than are changes in the underlying risk structure in a population. Conversely, nearly universal declines in O/E ratios for smoking and alcohol use indicate that, for a given SDI, exposure to these risks is declining. In 2017, the leading Level 4 risk factor for age-standardised DALY rates was high SBP in four super-regions: central Europe, eastern Europe, and central Asia; north Africa and Middle East; south Asia; and southeast Asia, east Asia, and Oceania. The leading risk factor in the high-income super-region was smoking, in Latin America and Caribbean was high BMI, and in sub-Saharan Africa was unsafe sex. O/E ratios for unsafe sex in sub-Saharan Africa were notably high, and those for alcohol use in north Africa and the Middle East were notably low.
Interpretation
By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health plannin
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