Search results for "Twins"
showing 10 items of 236 documents
Heritability of refractive astigmatism: a population-based twin study among 63- to 75-year-old female twins.
2013
PURPOSE: To examine the heritability of refractive astigmatism in older women. METHODS: Astigmatism was measured with an autorefractor in 88 monozygotic and 82 dizygotic female twin pairs aged 63 to 75 years. The prevalence and distribution of astigmatism and polar values J0 and J45 were estimated by standard statistical methods. Bivariate maximum likelihood model fitting was used to estimate genetic and environmental variance components using information from both eyes. RESULTS: Mean astigmatism of the more astigmatic eye was 0.93 diopters (D; SD ±0.58). Astigmatism of at least 0.25 D, 0.5 D, 0.75 D, or 1.0 D in either eye was present in 99.7%, 88.5%, 66.5%, and 46.2% of cases, respectivel…
Longitudinal changes in genetic and environmental influences on older women's walking ability
2009
This study examined the stability and change over time in genetic and environmental influences on walking ability among older women. Maximal walking speed over 10 m and 6-min walking endurance test were measured under standard conditions at baseline and 3 years later. At both times, 63 monozygotic (MZ) and 67 dizygotic (DZ) twin pairs were measured for walking speed and 58 MZ and 56 DZ pairs for walking endurance. Participants were twin sisters reared together and aged 63-75 years at baseline. Genetic and environmental influences were examined using longitudinal genetic modelling. The results showed that walking speed was preserved from baseline to follow-up. Genetic influences on walking s…
Human digital twins and cognitive mimetic
2021
Digital twins – digital models of technical systems and processes – have recently been introduced to work with complex industrial processes. Yet should such models concern only physical objects (as definitions of them often imply), or should users and other human beings also be included? Models that include people have been called human digital twins (HDTs); they facilitate more accurate analyses of technologies in practical use. The cognitive mimetic approach can be used to describe human interactions with technologies. This approach analyses human information processes such as perceiving and thinking to mimic how people process information in order to design intelligent technologies. The …
A Digital Twin predictive maintenance framework of air handling units based on automatic fault detection and diagnostics
2022
The building industry consumes the most energy globally, making it a priority in energy efficiency initiatives. Heating, ventilation, and air conditioning (HVAC) systems create the heart of buildings. Stable air handling unit (AHU) functioning is vital to ensuring high efficiency and extending the life of HVAC systems. This research proposes a Digital Twin predictive maintenance framework of AHU to overcome the limitations of facility maintenance management (FMM) systems now in use in buildings. Digital Twin technology, which is still at an initial stage in the facility management industry, use Building Information Modeling (BIM), Internet of things (IoT) and semantic technologies to create…
Progetto Digital Twins: un sopralluogo analogico e digitale a Gratosoglio. Lo sguardo da Palermo
2022
The description of an ongoing project has the value of establishing some points of reflection useful to adjust the shot for the next phases of an experiment. In this paper, we are describing an ongoing project between Politecnico di Milano and Università degli Studi di Palermo. The feature on which this experimentation focuses is the analog/ digital survey, which tries to generate a “satellite” point of view, (a group of people physically in the analyzed area), and a “remote” one. The paper, firstly underlines the importance of surveys in urban planning, secondly displays the techniques, operators and equipment which are needed and it concludes with some considerations.
Pacemaker therapy in premature children with high degree AV block.
1998
The smallest pacemaker pulse generator and a steroid-eluting bipolar epicardial lead were implanted in two premature children with symptomatic AV block. Stable capture threshold and high amplitude evoked response electrogram resulted in normal function of the pacemaker Autocapture algorithm, which adjusts output 0.3 V above the measured capture threshold. Autocapture had previously been used only with endocardial leads. Longer-term observation is required.
On the family of $r$-regular graphs with Grundy number $r+1$
2014
International audience; The Grundy number of a graph $G$, denoted by $\Gamma(G)$, is the largest $k$ such that there exists a partition of $V(G)$, into $k$ independent sets $V_1,\ldots, V_k$ and every vertex of $V_i$ is adjacent to at least one vertex in $V_j$, for every $j < i$. The objects which are studied in this article are families of $r$-regular graphs such that $\Gamma(G) = r + 1$. Using the notion of independent module, a characterization of this family is given for $r=3$. Moreover, we determine classes of graphs in this family, in particular the class of $r$-regular graphs without induced $C_4$, for $r \le 4$. Furthermore, our propositions imply results on partial Grundy number.
Influence of Twinning Microstructure of Crystals with Low Tetragonality on a X-Ray Diffraction
2001
The intensity distributions of the X-rays scattered in the tetragonal single crystal, which represent a complex of the twin domains separated by the coherent parallel boundaries, are simulated. The calculations are performed by using the Monte Carlo method within the framework of a kinematical approach. The thickness distributions of the twin domains are defined according to the geometrical, Gaussian and log normal functions. ‘Critical’ effects of the X-ray scattering are found, namely there is transformation of the tetragonal doublet into singlet or multiplet. As demonstrated, each of characteristics of the tetragonal doublet profile depends on a few parameters of the twin microstructure o…
Genetics in restless legs syndrome
2004
Several studies on Restless leas syndrome (RLS) have suggested a substantial genetic contribution in the etiology of this sleep disorder. Clinical surveys of idiopathic RLS patients have shown that up to 60% report a positive family history. Investigations of single families with RLS have suggested an autosomal dominant mode of inheritance with variable expressivity, and some families show possible anticipation. At present, only one twin study is available, showing a high concordance rate (83.3%) between identical twins. Despite several reports suggesting a genetic contribution to the etiology of idiopathic RLS, few molecular genetic studies have been carried out attempting to identify gene…
Genetic influences on adult body mass index followed over 29 years and their effects on late-life mobility: a study of twin sisters.
2009
Background: The rise in body mass index (BMI) during adulthood increases the risk for metabolic disorders, functional limitations and disability in old age. This twin study examined prospectively whether genetic and environmental influences on women’s BMI also account for mobility 29 years later. Methods: The sample consisted of 103 monozygotic and 114 dizygotic pairs of twin sisters reared together. Body mass index was initially evaluated in 1975, when the women were aged 42.6±3.4 years, and was followed-up in 1981, 1990, 2001 and 2004. Mobility was evaluated using the standardised 6-minute walking test in 2001, when the women were aged 68.6±3.2 years, and followed-up 3 years later. An inv…