952 resultados para Fractal dimension


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Abstract Background Using univariate and multivariate variance components linkage analysis methods, we studied possible genotype × age interaction in cardiovascular phenotypes related to the aging process from the Framingham Heart Study. Results We found evidence for genotype × age interaction for fasting glucose and systolic blood pressure. Conclusions There is polygenic genotype × age interaction for fasting glucose and systolic blood pressure and quantitative trait locus × age interaction for a linkage signal for systolic blood pressure phenotypes located on chromosome 17 at 67 cM.

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OBJECTIVE: To review scientific literature relating to the spiritual dimension of children and adolescents with cancer. METHODS: We conducted an integrative literature review in the LILACS, SciELO, PsycINFO and MEDLINE databases in the period between 1990 to 2011. RESULTS: Twenty-one studies were analyzed and grouped into thematic categories: quality of life and elements of spirituality; alternative and complementary therapies: spirituality as a therapeutic resource; spirituality as a coping strategy and spirituality as an attribute of existential transformations. It was found that spirituality is present at different stages of the disease experience and that its forms of expression may vary, according to age and cognitive development. CONCLUSION: There is a scarcity of specific scales for this age range and a need for scientific production relating to the spiritual dimension of children and adolescents with cancer. Descriptors: Neoplasms; Children; Adolescents; Spirituality

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OBJECTIVE: To assess the effects of rapid maxillary expansion on facial morphology and on nasal cavity dimensions of mouth breathing children by acoustic rhinometry and computed rhinomanometry. METHODS: Cohort; 29 mouth breathing children with posterior crossbite were evaluated. Orthodontic and otorhinolaryngologic documentation were performed at three different times, i.e., before expansion, immediately after and 90 days following expansion. RESULTS: The expansion was accompanied by an increase of the maxillary and nasal bone transversal width. However, there were no significant differences in relation to mucosal area of the nose. Acoustic rhinometry showed no difference in the minimal cross-sectional area at the level of the valve and inferior turbinate between the periods analyzed, although rhinomanometry showed a statistically significant reduction in nasal resistance right after expansion, but were similar to pre-treatment values 90 days after expansion. CONCLUSION: The maxillary expansion increased the maxilla and nasal bony area, but was inefficient to increase the nasal mucosal area, and may lessen the nasal resistance, although there was no difference in nasal geometry. Significance: Nasal bony expansion is followed by a mucosal compensation.

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In this work, we discuss some theoretical topics related to many-body physics in ultracold atomic and molecular gases. First, we present a comparison between experimental data and theoretical predictions in the context of quantum emulator of quantum field theories, finding good results which supports the efficiency of such simulators. In the second and third parts, we investigate several many-body properties of atomic and molecular gases confined in one dimension.

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Diese Arbeit besch"aftigt sich mit algebraischen Zyklen auf komplexen abelschen Variet"aten der Dimension 4. Ziel der Arbeit ist ein nicht-triviales Element in $Griff^{3,2}(A^4)$ zu konstruieren. Hier bezeichnet $A^4$ die emph{generische} abelsche Variet"at der Dimension 4 mit Polarisierung von Typ $(1,2,2,2)$. Die ersten drei Kapitel sind eine Wiederholung von elementaren Definitionen und Begriffen und daher eine Festlegung der Notation. In diesen erinnern wir an elementare Eigenschaften der von Saito definierten Filtrierungen $F_S$ und $Z$ auf den Chowgruppen (vgl. cite{Sa0} und cite{Sa}). Wir wiederholen auch eine Beziehung zwischen der $F_S$-Filtrierung und der Zerlegung von Beauville der Chowgruppen (vgl. cite{Be2} und cite{DeMu}), welche aus cite{Mu} stammt. Die wichtigsten Begriffe in diesem Teil sind die emph{h"ohere Griffiths' Gruppen} und die emph{infinitesimalen Invarianten h"oherer Ordnung}. Dann besch"aftigen wir uns mit emph{verallgemeinerten Prym-Variet"aten} bez"uglich $(2:1)$ "Uberlagerungen von Kurven. Wir geben ihre Konstruktion und wichtige geometrische Eigenschaften und berechnen den Typ ihrer Polarisierung. Kapitel ref{p-moduli} enth"alt ein Resultat aus cite{BCV} "uber die Dominanz der Abbildung $p(3,2):mathcal R(3,2)longrightarrow mathcal A_4(1,2,2,2)$. Dieses Resultat ist von Relevanz f"ur uns, weil es besagt, dass die generische abelsche Variet"at der Dimension 4 mit Polarisierung von Typ $(1,2,2,2)$ eine verallgemeinerte Prym-Variet"at bez"uglich eine $(2:1)$ "Uberlagerung einer Kurve vom Geschlecht $7$ "uber eine Kurve vom Geschlecht $3$ ist. Der zweite Teil der Dissertation ist die eigentliche Arbeit und ist auf folgende Weise strukturiert: Kapitel ref{Deg} enth"alt die Konstruktion der Degeneration von $A^4$. Das bedeutet, dass wir in diesem Kapitel eine Familie $Xlongrightarrow S$ von verallgemeinerten Prym-Variet"aten konstruieren, sodass die klassifizierende Abbildung $Slongrightarrow mathcal A_4(1,2,2,2)$ dominant ist. Desweiteren wird ein relativer Zykel $Y/S$ auf $X/S$ konstruiert zusammen mit einer Untervariet"at $Tsubset S$, sodass wir eine explizite Beschreibung der Einbettung $Yvert _Thookrightarrow Xvert _T$ angeben k"onnen. Das letzte und wichtigste Kapitel enth"ahlt Folgendes: Wir beweisen dass, die emph{ infinitesimale Invariante zweiter Ordnung} $delta _2(alpha)$ von $alpha$ nicht trivial ist. Hier bezeichnet $alpha$ die Komponente von $Y$ in $Ch^3_{(2)}(X/S)$ unter der Beauville-Zerlegung. Damit und mit Hilfe der Ergebnissen aus Kapitel ref{Cohm} k"onnen wir zeigen, dass [ 0neq [alpha ] in Griff ^{3,2}(X/S) . ] Wir k"onnen diese Aussage verfeinern und zeigen (vgl. Theorem ref{a4}) begin{theorem}label{maintheorem} F"ur $sin S$ generisch gilt [ 0neq [alpha _s ]in Griff ^{3,2}(A^4) , ] wobei $A^4$ die generische abelsche Variet"at der Dimension $4$ mit Polarisierung vom Typ $(1,2,2,2)$ ist. end{theorem}

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In this thesis, the influence of composition changes on the glass transition behavior of binary liquids in two and three spatial dimensions (2D/3D) is studied in the framework of mode-coupling theory (MCT).The well-established MCT equations are generalized to isotropic and homogeneous multicomponent liquids in arbitrary spatial dimensions. Furthermore, a new method is introduced which allows a fast and precise determination of special properties of glass transition lines. The new equations are then applied to the following model systems: binary mixtures of hard disks/spheres in 2D/3D, binary mixtures of dipolar point particles in 2D, and binary mixtures of dipolar hard disks in 2D. Some general features of the glass transition lines are also discussed. The direct comparison of the binary hard disk/sphere models in 2D/3D shows similar qualitative behavior. Particularly, for binary mixtures of hard disks in 2D the same four so-called mixing effects are identified as have been found before by Götze and Voigtmann for binary hard spheres in 3D [Phys. Rev. E 67, 021502 (2003)]. For instance, depending on the size disparity, adding a second component to a one-component liquid may lead to a stabilization of either the liquid or the glassy state. The MCT results for the 2D system are on a qualitative level in agreement with available computer simulation data. Furthermore, the glass transition diagram found for binary hard disks in 2D strongly resembles the corresponding random close packing diagram. Concerning dipolar systems, it is demonstrated that the experimental system of König et al. [Eur. Phys. J. E 18, 287 (2005)] is well described by binary point dipoles in 2D through a comparison between the experimental partial structure factors and those from computer simulations. For such mixtures of point particles it is demonstrated that MCT predicts always a plasticization effect, i.e. a stabilization of the liquid state due to mixing, in contrast to binary hard disks in 2D or binary hard spheres in 3D. It is demonstrated that the predicted plasticization effect is in qualitative agreement with experimental results. Finally, a glass transition diagram for binary mixtures of dipolar hard disks in 2D is calculated. These results demonstrate that at higher packing fractions there is a competition between the mixing effects occurring for binary hard disks in 2D and those for binary point dipoles in 2D.

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It is not well known if the size of the ascending thoracic aorta at presentation predicts features of presentation, management, and outcomes in patients with acute type B aortic dissection. The International Registry of Acute Aortic Dissection (IRAD) database was queried for all patients with acute type B dissection who had documentation of ascending thoracic aortic size at time of presentation. Patients were categorized according to ascending thoracic aortic diameters ≤4.0, 4.1 to 4.5, and ≥4.6 cm. Four hundred eighteen patients met inclusion criteria; 291 patients (69.6%) were men with a mean age of 63.2 ± 13.5 years. Ascending thoracic aortic diameter ≤4.0 cm was noted in 250 patients (59.8%), 4.1 to 4.5 cm in 105 patients (25.1%), and ≥4.6 cm in 63 patients (15.1%). Patients with an ascending thoracic aortic diameter ≥4.6 cm were more likely to be men (p = 0.01) and have Marfan syndrome (p <0.001) and known bicuspid aortic valve disease (p = 0.003). In patients with an ascending thoracic aorta ≥4.1 cm, there was an increased incidence of surgical intervention (p = 0.013). In those with an ascending thoracic aorta ≥4.6 cm, the root, ascending aorta, arch, and aortic valve were more often involved in surgical repair. Patients with an ascending thoracic aorta ≤4.0 were more likely to have endovascular therapy than those with larger ascending thoracic aortas (p = 0.009). There was no difference in overall mortality or cause of death. In conclusion, ascending thoracic aortic enlargement in patients with acute type B aortic dissection is common. Although its presence does not appear to predict an increased risk of mortality, it is associated with more frequent open surgical intervention that often involves replacement of the proximal aorta. Those with smaller proximal aortas are more likely to receive endovascular therapy.