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1.
Environ Monit Assess ; 193(2): 91, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33502597

RESUMO

Soil moisture content is a key factor affecting surface evaporation in the hydrologic cycle, with application in water resources management, early drought warning system, irrigation management, and estimation of crop yield. The subject of soil moisture content has long been of interest in hydrology, agriculture, forestry, and soil mechanics engineering. The cracking of surface soil due to dryness is often used to describe the drought condition of the land based on the certain relationship between soil cracking and moisture content. This study establishes the relation between fractal dimensions of soil cracking patterns and moisture content of surface soil. Sixteen soil samples were prepared and subjected to drying under different temperature levels to crack in the laboratory. Photographs of the cracks were digitized and an algorithm for calculating fractal dimensions of cracking patterns was developed. The results demonstrated that the fractal dimensions of cracking patterns are highly correlated with the surface soil moisture content; the lower the soil moisture content, the larger the fractal dimension is. Therefore, the surface soil moisture content-fractal dimension (DB-w) rating curves can be established. Once crack structures occur on surface soil, the moisture content of the surface soil can be estimated quickly and accurately by mean of remote sensing technique such as UAV together with the fractal analysis.


Assuntos
Fractais , Solo , Agricultura , Monitoramento Ambiental , Água/análise
2.
Nonlinear Dynamics Psychol Life Sci ; 25(1): 113-123, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33308392

RESUMO

Artistic technique and scientific discovery are superficially contradictory, but are unified at their core as products of creativity. I have always embraced both disciplines, but at some point during my academic journey, I lost my imagination and ability to dream creatively. For over a decade, I have remained passionate about perfecting a way to retrieve this intrinsic component of myself, and nurture it in my students and peers. We must think anew and act anew - bridge the gulf between the disciplines of art and science - if we are to rescue creativity in scientific discovery, and retain many of the bright minds that burn out and even leave academia in science. Surrealism and fractals in nature are such bridges, and offer a space for early career scientists to embrace the full breadth and cultural capacity of science. Here, I present a retrospective review of artworks I have produced over nearly two decades, in considering how they reflect my mindset and relationship with science at various stages of my academic journey.


Assuntos
Arte , Criatividade , Fractais , Ciência , Humanos , Estudos Retrospectivos , Estudantes
3.
J Environ Sci (China) ; 101: 168-176, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33334513

RESUMO

Structure properties of flocs (size, fractal dimension (Df), etc.) have a high impact on coagulation efficiency. In this work, the influences of three different additives (ferric salt (Fe), phosphate (P), and citric acid (CA)) on coagulation process/efficiency were investigated. Results showed that a small amount of extra Fe can facilitate the growth of Al flocs by providing more 'active sites'. Although zeta potential and Df showed a limited change, the average floc size increased apparently and the increment was more obvious when Fe was added after the formation of the flocs. In contrast, P addition during the rapid mixing period will decrease the final average floc size, while the influence is less significant when P was added after the growth of the flocs. In terms of CA, a more striking negative effect on the growth ability of the flocs was observed compared to P. The strong complexing/coordination interactions between CA and aluminum hydroxide is the main reason behind the influence. CA also significantly decreased the Df value of the flocs compared to P, and Df showed a comparatively higher decrease when P or CA was added during the rapid mixing stage compared to the addition after the flocs formation. These results indicated that the addition of CA or P during the rapid mixing stage 'inactivated' or occupied more 'active sites' on the preliminarily formed Al NPs during the hydrolysis process, and therefore presented stronger impact on the morphology/size of the formed flocs.


Assuntos
Purificação da Água , Hidróxido de Alumínio , Compostos Férricos , Floculação , Fractais
4.
Angle Orthod ; 90(6): 783-793, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378509

RESUMO

OBJECTIVE: To evaluate the effects of functional appliance treatment on mandibular trabecular structure using fractal dimension (FD) analysis of dental panoramic radiographs. MATERIALS AND METHODS: This study was conducted using digital panoramic radiographs of 45 patients with Class II malocclusion treated with functional appliances (treatment group, mean age: 11.39 ± 0.97 years; 23 girls, 22 boys) acquired before (T0) and after (T1) treatment and the panoramic radiographs of 45 control subjects who had undergone no orthodontic treatment (control group, mean age: 11.31 ± 0.87 years; 23 girls, 22 boys). FD values in the condylar process, mandibular corpus, and mandibular angle were analyzed from the panoramic radiographs of both groups. RESULTS: Analysis of changes in FD between T0 and T1 revealed significant increases in the FD values of the right and left condylar processes and right mandibular corpus in the treatment group (P < .001) and in the right condylar process in the control group (P < .05). Between-group comparisons demonstrated that the treatment group showed greater changes in the condylar process (right, P < .001; left, P < .05) and right mandibular corpus (P < .05) compared to controls. Correlation analysis between the cephalometric and FD changes in the treatment group showed the right condylar process changes were negatively correlated with GoGn/SN angle (P < .05) and positively correlated with Co-Go (P < .05), although these correlations were weak. CONCLUSIONS: FD analysis demonstrated significant changes in trabeculation of the condyle and mandibular corpus in the treatment group compared to the control group. Functional appliance treatment may lead to skeletal correction by altering skeletal form and trabeculation of the mandibular bone.


Assuntos
Fractais , Má Oclusão de Angle Classe II , Cefalometria , Criança , Feminino , Humanos , Masculino , Má Oclusão de Angle Classe II/diagnóstico por imagem , Má Oclusão de Angle Classe II/terapia , Mandíbula/diagnóstico por imagem , Radiografia Panorâmica
5.
PLoS One ; 15(12): e0235802, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33332349

RESUMO

Sutures, the thin, soft tissue between skull bones, serve as the major craniofacial growth centers during postnatal development. In a newborn skull, the sutures are straight; however, as the skull develops, the sutures wind dynamically to form an interdigitation pattern. Moreover, the final winding pattern had been shown to have fractal characteristics. Although various molecules involved in suture development have been identified, the mechanism underlying the pattern formation remains unknown. In a previous study, we reproduced the formation of the interdigitation pattern in a mathematical model combining an interface equation and a convolution kernel. However, the generated pattern had a specific characteristic length, and the model was unable to produce a fractal structure with the model. In the present study, we focused on the anterior part of the sagittal suture and formulated a new mathematical model with time-space-dependent noise that was able to generate the fractal structure. We reduced our previous model to represent the linear dynamics of the centerline of the suture tissue and included a time-space-dependent noise term. We showed theoretically that the final pattern from the model follows a scaling law due to the scaling of the dispersion relation in the full model, which we confirmed numerically. Furthermore, we observed experimentally that stochastic fluctuation of the osteogenic signal exists in the developing skull, and found that actual suture patterns followed a scaling law similar to that of the theoretical prediction.


Assuntos
Suturas Cranianas/crescimento & desenvolvimento , Animais , Fractais , Humanos , Recém-Nascido , Camundongos , Modelos Biológicos , Modelos Teóricos , Morfogênese/fisiologia , Osteogênese/fisiologia
6.
Comput Math Methods Med ; 2020: 9214159, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33082843

RESUMO

Traditionally, the identification of parameters in the formulation and solution of inverse problems considers that models, variables, and mathematical parameters are free of uncertainties. This aspect simplifies the estimation process, but does not consider the influence of relatively small changes in the design variables in terms of the objective function. In this work, the SIDR (Susceptible, Infected, Dead, and Recovered) model is used to simulate the dynamic behavior of the novel coronavirus disease (COVID-19), and its parameters are estimated by formulating a robust inverse problem, that is, considering the sensitivity of design variables. For this purpose, a robust multiobjective optimization problem is formulated, considering the minimization of uncertainties associated with the estimation process and the maximization of the robustness parameter. To solve this problem, the Multiobjective Stochastic Fractal Search algorithm is associated with the Effective Mean concept for the evaluation of robustness. The results obtained considering real data of the epidemic in China demonstrate that the evaluation of the sensitivity of the design variables can provide more reliable results.


Assuntos
Betacoronavirus , Infecções por Coronavirus/epidemiologia , Modelos Estatísticos , Pandemias , Pneumonia Viral/epidemiologia , Algoritmos , China/epidemiologia , Biologia Computacional , Simulação por Computador , Fractais , Humanos , Pandemias/estatística & dados numéricos , Processos Estocásticos , Incerteza
7.
J Vis Exp ; (163)2020 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-33044462

RESUMO

Laminin-111 (Ln1) is an essential part of the extracellular matrix in epithelia, muscle and neural systems. We have previously demonstrated that the microstructure of Ln1 alters the way that it signals to cells, possibly because Ln1 assembly into networks exposes different adhesive domains. In this protocol, we describe three methods to generate polymerized Ln1.


Assuntos
Laminina/metabolismo , Transdução de Sinais , Matriz Extracelular/metabolismo , Fractais , Laminina/química , Polimerização
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3371-3374, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018727

RESUMO

Microelectrodes are basic tools for investigating small-scale brain dynamics. Noble metals such as gold (Au), platinum (Pt), and iridium oxide (IrOx) have been used as an electrode material because of their biocompatibility and good charge transfer capability. Their main charge transfer mechanism is the Faradaic process with redox reactions. Unfortunately, the decrease in electrode size accelerates the irreversible electrochemical dissolution during electrical stimulation due to increased current density. The dissolution can be prevented by alternating the electrode material to capacitive charge injection materials such as titanium nitride (TiN). However, electrical conductivity of TiN is relatively lower than the noble metals, which results in a lower charge injection capability. Therefore, there is a need to increase the charge injection limit of TiN electrodes for a high-performing neurostimulation. Our previous work suggested that the Vicseck fractal design can increase the charge injection limit of the microelectrodes. In this work, the effects of the fractal design in capacitive charge injection material were experimentally investigated by using TiN microelectrodes with circular and fractal designs. We measured the cyclic voltammetry, electrochemical impedance spectroscopy, and voltage transients. In addition, the charge injection limits of theses microelectrodes were estimated to quantify the effects of planar geometry on TiN microelectrodes. Despite our previous results showing superior charge injection capability of fractal Pt microelectrodes, the TiN showed no significant improvements due to the fractal geometry. This may be because the increase in charge injection capability of fractal microelectrodes is due to increased Faradaic charge injection process, which is minimized for TiN materials. Thus, our data suggests that the material as well as the geometry of the microelectrodes play key roles in optimizing stimulation microelectrode performance.Clinical relevance-As with the Faradaic charge injection-dominant materials, the capacitive charge injection materials could also benefit from additional investigation to fully characterize effects of electrode geometry for improved neurostimulation performance.


Assuntos
Fractais , Titânio , Microeletrodos , Platina
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4089-4092, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018897

RESUMO

This paper reports on a novel transducer for wireless biochemical sensing. The bilayer transducer consists of a fractal piezoelectric membrane and pH-sensitive chemo-mechanical hydrogel, which overcomes many shortcomings in the chemical and biochemical sensing. The fractal design on the piezoelectric membrane enhances frequency response and linearity by employing periodically repeated pore architecture. As a basis of the pore, a Hilbert space-filling curve with modifications is used. On the surface of the fractal piezoelectric membrane, the hydrogel is laminated. When the bilayer transducer is introduced to a pH environment (e.g., pH = 4, 8, and 12), the hydrogel swells (or shrinks) and induces the curling of the bilayer transducer (10.47°/pH). The curvature then exhibits various ultrasound responses when the bilayer transducer was excited. The measured voltage outputs using an ultrasonic receiver were 0.393, 0.341, 0.250 mV/cm2 when curvature angles were 30°, 60°, and 120°, respectively. Overall pH sensitivity was 0.017 mV/cm2/pH. Ultimately, the biochemical sensing principle using a novel bilayer ultrasound transducer suggests a simple, low-cost, battery-less, and long-range wireless readout system as compared to traditional biochemical sensing.


Assuntos
Fractais , Hidrogéis , Transdutores , Ultrassonografia
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 276-279, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33017982

RESUMO

The aim of this study was to evaluate individual level of natural variability of electroencephalogram (EEG) based markers. Three linear: alpha power variability, spectral asymmetry index, relative gamma power and three nonlinear methods: Higuchi's fractal dimension, detrended fluctuation analysis, and Lempel-Ziv complexity were selected. The markers were evaluated over 15 sessions acquired in 14 months. The results indicate that individual natural variability for five of the selected markers is lower compared to differences between healthy and depressed groups of subjects in our previous studies. The results of the current study suggest that EEG based markers can be applied for evaluation of disturbances in brain activity at individual level.Clinical Relevance-The indicated stability in the current study of widely used EEG-based markers at individual level suggests a promising opportunity to apply EEG as a novel method in diagnoses of brain mental disorders in clinical practice.


Assuntos
Encéfalo , Eletroencefalografia , Estudos de Casos e Controles , Fractais , Reprodutibilidade dos Testes
11.
Clin Ter ; 171(5): e385-e392, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32901779

RESUMO

BACKGROUND: Marginal bone loss (MBL) represents an important indicator of peri-implant health and the measure of its level is considered a determining factor in the evaluation of the quality of survival. Aim of this study is to compare radiographic changes in the fractal and mesial/distal vertical dimensions of peri-implant trabecular bone of dental implants with a laser-ablated micron-scale modication (LAM) of collar surface after a 5-year follow-up period. MATERIALS AND METHODS: Thirty-four implants with LAM of collar surface (test group = TG) and 31 implants without LAM of collar surface (control group = CG) were placed in 45 non-smoking, periodontally healthy patients. Fractal and vertical dimensions of peri-implant trabecular bone were measured by comparing radiographs taken immediately after prosthesis delivery with those taken 3 years and 5 years after functional loading. RESULT: At the end of the 5-year follow-up, the MBL in the TG was 0.87±0.21 and 0.75±0.25 mm at the mesial and distal aspects, respectively, while a MBL of 2.05±0.25 mm at the mesial aspect and 2.01±0.34 mm at the distal site was recorded in the CG. A statistically significant difference was noted. In the TG the mean fractal dimension before loading was 1.4213±0.0525. It increased significantly to 1.4329±0.0479 at 3 years after loading and remained almost stable at 5 years after loading (1.4327±0.0291). In the CG the mean fractal dimension before loading was 1.4119±0.0414. It increased significantly to 1.4282±0.0324 at 3 years after loading and decreased significantly to 1.4111±0.0624 at 5 years after loading. At the end of the follow-up, differences between both study groups were statistically significant. CONCLUSION: The increased fractal dimension and the reduced MBL around TG implants after 5 years of functional loading indicates a positive effect of a laser-ablated micron-scale modication of collar surface on peri-implant trabecular bone remodeling.


Assuntos
Osso Esponjoso/cirurgia , Implantes Dentários , Terapia a Laser , Adulto , Osso Esponjoso/diagnóstico por imagem , Feminino , Seguimentos , Fractais , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia , Estudos Retrospectivos , Propriedades de Superfície
12.
Bioresour Technol ; 318: 124050, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32889118

RESUMO

Enzymatic hydrolysis of three pre-treated lignocellulosic biomasses -LCB- (wheat straw-WS-, corn stover-CSV- and cardoon stems -CS-) is studied. These biomasses were pre-treated by two methods: diluted sulfuric acid and acid ethanol-water extraction at six severity levels (H values). Pretreated solid fractions were hydrolyzed with commercial enzyme cocktails at standard conditions. A first-order kinetic fractal model was fitted to the experimental results. This model accurately describes the hydrolysis of all biomasses at all pre-treatment conditions studied. The results show that the formal first-order kinetic constant k depends on the biomass nature. The hydrolysis rate increases as the pre-treatment severity does, while the fractal exponent value h decreases. With these pre-treatments, and in terms of k and h, WS is highly reactive and, at medium H with EW pretreatment, highly accessible; CSV has a low reactivity and high accessibility and CS has the lowest reactivity and an increasing accessibility as severity rises.


Assuntos
Celulase , Biomassa , Fractais , Hidrólise , Lignina
13.
Nonlinear Dynamics Psychol Life Sci ; 24(4): 389-402, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32960754

RESUMO

This article presents the geometrical-fractal text-tree model of speech and writing, the development of which is part of a project with the long-term goal to answer the question whether Artificial Intelligence and the corresponding human intelligence are principally different or not. Text-tree models consist of word-shrubs 'glued' together by syntax. Word-shrubs are designed by means of two principles, one is the dictionary or semantic principle that we can explain all verbal meanings by the meanings of other words. The other is the initiator-generator procedure, used to develop geometrical fractals. The structure of the word-shrub grows from the root-word when the meaning of the root-word, the generator, is connected as a branch to the root-word which is first initiator. Then all generator words are redefined as new initiators and connected to their meaning, the second generators. But the words or these are redefined as new initiators, each then being connected to its generator-meaning. This is repeated ad infinitum. Each new layer of generators represents a branching level. Consistency of verbal meaning is achieved by fixing the number of branching levels of the word-shrub. Wobbling consistency occurs when the talking or writing person shifts between levels of branching. We develop the M-method, important for most of the results, because it allows differences in verbal meaning to be estimated numerically. An interesting property of the text-tree model is revealed by showing that there must exist a cloud of unexperienced meaning variants of human texts. Most interesting, perhaps, is the demonstration of what we call the lemma of incompleteness which states that humans cannot prove beyond doubt, that they understand correctly what they say and write. This lemma seems to be a distant barrier for the expansion of human understanding and of relevance for understanding human versus artificial intelligence.


Assuntos
Inteligência Artificial , Fractais , Humanos , Semântica
14.
Artigo em Inglês | MEDLINE | ID: mdl-32751316

RESUMO

Although mandatory in most high-risk industries, the safety management system (SMS) is often criticized as burdensome and complex. Through its requirement to formalize all main activities, the SMS is perceived as bureaucratic and a vehicle for pure compliance and Safety I (one). Furthermore, the SMS is often detached from an organization's core activities, goes against local practice and does not deliver the safe performance that was hoped for. By comparing the model behind SMS with specific requirements for process capability, this paper identifies a safety fractal that reflects the basic requirements that are needed to control safety related activities at all levels within an organization. It is further argued that the constituent elements of this safety fractal are particularly suitable to organize resilient performance, provided that resilience is explicitly identified as the safety strategy to follow and, as such, consequently implemented. This approach is then positioned against common safety management concepts as management system maturity, leadership and safety culture, leading to a systematic and a more comprehensive view on how to measure safety performance and resilience.


Assuntos
Fractais , Gestão da Segurança , Liderança , Organizações
15.
PLoS One ; 15(8): e0234169, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810131

RESUMO

Toxoplasma gondii is an obligate intracellular parasite infecting up to one third of the human population. The central event in the pathogenesis of toxoplasmosis is the conversion of tachyzoites into encysted bradyzoites. A novel approach to analyze the structure of in vivo-derived tissue cysts may be the increasingly used computational image analysis. The objective of this study was to quantify the geometrical complexity of T. gondii cysts by morphological, particle, and fractal analysis, as well as to determine if it is impacted by parasite strain, cyst age, and host type. A total of 31 images of T. gondii brain cysts of four type-2 strains (Me49, and local isolates BGD1, BGD14, and BGD26) was analyzed using ImageJ software. The parameters of interest included diameter, circularity, packing density (PD), fractal dimension (FD), and lacunarity. Although cyst diameter varied widely, its negative correlation with PD was observed. Circularity was remarkably close to 1, indicating a perfectly round shape of the cysts. PD and FD did not vary among cysts of different strains, age, and derived from mice of different genetic background. Conversely, lacunarity, which is a measure of heterogeneity, was significantly lower for BGD1 strain vs. all other strains, and higher for Me49 vs. BGD14 and BGD26, but did not differ among Me49 cysts of different age, or those derived from genetically different mice. The results indicate a highly uniform structure and occupancy of the different T. gondii tissue cysts. This study furthers the use of image analysis in describing the structural complexity of T. gondii cyst morphology, and presents the first application of fractal analysis for this purpose. The presented results show that use of a freely available software is a cost-effective approach to advance automated image scoring for T. gondii cysts.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Toxoplasma/citologia , Toxoplasmose Animal/patologia , Toxoplasmose Animal/parasitologia , Animais , Encéfalo/parasitologia , Encéfalo/patologia , Cistos/parasitologia , Cistos/patologia , Feminino , Fractais , Interações Hospedeiro-Parasita , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Toxoplasma/patogenicidade , Toxoplasma/ultraestrutura
16.
Water Res ; 185: 116287, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32810744

RESUMO

Although a combination of aggregate characteristics dictate particle settling, it is commonly assumed that large particles have higher terminal velocities. This simplifying assumption often leads to overprediction of large aggregate settling velocities which in turn negatively impacts on estimates of sedimentation clarification efficiency. Despite its importance, little attention has been given to large aggregates with slow-settling velocities. This paper addresses this gap by investigating slow-settling velocities of large, heterodisperse and multi-shape Al-kaolin aggregates using non-intrusive methods. A particle image velocimetry technique (PIV) was applied to track aggregate velocity and a non-intrusive image technique was used to determine aggregate characteristics, including size (df), three-dimensional fractal dimension (Df), density (ρf), aggregate velocity (Vexp) and Reynolds number (Re). Results showed no strict dependence of settling velocity on large aggregate size, shape and density, as Al-kaolin aggregates with the same size exhibited different settling velocities. A comparison of the results with the well-known Stokes' law for velocity modified by a shape factor showed that the settling velocities measured here can vary from 2 to 14 fold lower than the predicted values for perfect sphere-shape aggregates with the same density and size. Furthermore, results have also shown large Al-kaolin aggregate's drag coefficient (Cd) to be around 56/Re, for average fractal aggregate sphericity of around 0.58.


Assuntos
Fractais , Caulim , Floculação , Tamanho da Partícula , Reologia
17.
PLoS One ; 15(8): e0237304, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780754

RESUMO

The COVID-19 pandemic has already had a shocking impact on the lives of everybody on the planet. Here, we present a modification of the classical SI model, the Fractal Kinetics SI model which is in excellent agreement with the disease outbreak data available from the World Health Organization. The fractal kinetic approach that we propose here originates from chemical kinetics and has successfully been used in the past to describe reaction dynamics when imperfect mixing and segregation of the reactants is important and affects the dynamics of the reaction. The model introduces a novel epidemiological parameter, the "fractal" exponent h which is introduced in order to account for the self-organization of the societies against the pandemic through social distancing, lockdowns and flight restrictions.


Assuntos
Betacoronavirus , Infecções por Coronavirus/epidemiologia , Fractais , Pneumonia Viral/epidemiologia , Infecções por Coronavirus/virologia , Humanos , Cinética , Pandemias , Pneumonia Viral/virologia , Análise de Componente Principal , Quarentena/métodos , Sociedades
18.
Nature ; 584(7822): 589-594, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32814899

RESUMO

The inner surfaces of the human heart are covered by a complex network of muscular strands that is thought to be a remnant of embryonic development1,2. The function of these trabeculae in adults and their genetic architecture are unknown. Here we performed a genome-wide association study to investigate image-derived phenotypes of trabeculae using the fractal analysis of trabecular morphology in 18,096 participants of the UK Biobank. We identified 16 significant loci that contain genes associated with haemodynamic phenotypes and regulation of cytoskeletal arborization3,4. Using biomechanical simulations and observational data from human participants, we demonstrate that trabecular morphology is an important determinant of cardiac performance. Through genetic association studies with cardiac disease phenotypes and Mendelian randomization, we find a causal relationship between trabecular morphology and risk of cardiovascular disease. These findings suggest a previously unknown role for myocardial trabeculae in the function of the adult heart, identify conserved pathways that regulate structural complexity and reveal the influence of the myocardial trabeculae on susceptibility to cardiovascular disease.


Assuntos
Doenças Cardiovasculares/genética , Fractais , Predisposição Genética para Doença , Coração/anatomia & histologia , Coração/fisiologia , Miocárdio/metabolismo , Adulto , Idoso , Animais , Doenças Cardiovasculares/fisiopatologia , Citoesqueleto/genética , Citoesqueleto/fisiologia , Técnicas de Inativação de Genes , Loci Gênicos/genética , Estudo de Associação Genômica Ampla , Coração/embriologia , Hemodinâmica , Humanos , Pessoa de Meia-Idade , Miocárdio/citologia , Oryzias/embriologia , Oryzias/genética , Fenótipo
19.
Caracas; Observatorio Nacional de Ciencia, Tecnología e Innovación; ago. 2020. 91-110 p. ilus, tab.(Observador del Conocimiento. Revista Especializada en Gestión Social del Conocimiento, 5, 2).
Monografia em Espanhol | LILACS, LIVECS | ID: biblio-1118176

RESUMO

La novedosa pandemia por coronavirus, etiquetada por la Organización Mundial de la Salud OMS, 2020) como la covid-19, se reportó por primera vez en Wuhan, China, el 31 de diciembre de 2019 y a la fecha, según estimaciones de la misma OMS (2020), en la medida en que se ha extendido a nivel planetario, ha infectado a más de 9,2 millones de personas, de las cuales se reportan más de 500.000 fallecidos y 5.2 millones de pacientes recuperados. En este estudio, aplicaremos el exponente de Hurst (1951) asociado con la estadística fractal para simular la propagación de la covid-19, considerando series temporales de fluctuaciones de nuevos casos diarios de la enfermedad, disponibles a través de un sitio web de referencia de la República Bolivariana de Venezuela, como lo es el Observatorio Nacional de Ciencia, Tecnología e Innovación (ONCTI). Se parte de la hipótesis de que la propagación de la covid-19, puede analizarse en función de las fluctuaciones del crecimiento de nuevos casos diarios de contagio. Para ello, se empleó un método de rango reescalado R/S que permitió calcular el Exponente de Hurst, parámetro estocástico cuyo valor permitió inferir sobre la presencia de correlaciones de largo alcance en la transmisión del virus entre la población. Estudiaremos los efectos de correlación en la propagación de COVID-19 en Venezuela mediante el análisis de las series temporales de nuevos casos después del decreto de Alerta dictado por el Ejecutivo Nacional que convocó a la ciudadanía a "quedarse en casa" mediante una cuarentena social obligatoria. Simularemos el comportamiento a mediano plazo (180 días) considerando las fluctuaciones de los nuevos casos de contagio diarios sobre la base de dos factores: los casos de contagio importados y los contagios comunitarios. En consecuencia, inicialmente examinaremos el origen de correlaciones con grandes fluctuaciones, y posteriormente analizaremos en base a las series de tiempo de nuevos casos diarios de la covid-19 en Venezuela, para luego establecer las correlaciones de largo alcance e inferir sobre la posible la persistencia o antipersistencia de la misma(AU)


The novel coronavirus pandemic, labeled by the World Health Organization (WHO) as Covid-19, was first reported in Wuhan, China, on December 31, 2019. To date, according to the WHO's estimates, it has infected more than 9.2 million people, of whom more than 500,000 are reported dead, and 5.2 million patients have recovered. To deepen in its study, we apply the Hurst exponent, associated with fractal statistics to simulate the spread of Covid-19, considering time series of fluctuations of new daily cases, which are available in a site reference website of the Bolivarian Republic of Venezuela, such as the National Observatory for Science, Technology, and Innovation (ONCTI). This work starts from the hypothesis that the spread of Covid-19 can be analyzed based on the fluctuations in the increase of new daily cases. For this, an R / S rescaled range method was used that allowed calculating the Hurst Exponent, a stochastic parameter whose value allowed inferring the presence of long-range correlations in the virus transmission among the population. We will study the correlation effects in the spread of COVID-19 in Venezuela by analyzing the time series of new cases after the alert decree issued by the Executive branch, which called on citizens to "stay at home" through a mandatory social quarantine. Consequently, initially, we will examine the origin of correlations with large fluctuations, followed by an analysis based on the time series of new daily cases of Covid-19 in Venezuela, in order to establish the long-range correlations and infer about the possible persistence or anti persistence of it(AU)


Assuntos
Humanos , Venezuela , Quarentena , Infecções por Coronavirus , Pandemias , Estudos de Séries Temporais , Fractais
20.
PLoS One ; 15(6): e0235257, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32589641

RESUMO

There is extensive evidence today linking exposure to natural environments to favorable changes in mental and even physical health. There is also a growing body of work indicating that there are specific geometric properties of natural scenes that mediate these effects, and that these properties can also be found in artificial structures like buildings, especially those designed before the emergence of modernism. These geometries are also associated with aesthetic preference-we seem to like what is good for us. Here, using a questionnaire-based survey, we have tried to elucidate some of the parameters that play a role in formulating a preference for one form over the other. The images used were nature scenes from the Alpine landscape with various manipulations to alter their complexity, or with additions of computer graphics or various buildings. In all cases, the presence of a natural scaling hierarchy and of either fractal graphics or of ornate, non-local pre-modern buildings was always preferable to the alternative. We discuss these findings under the light of recent evidence in the field and conclude that they support the idea of the existence of a preference of our perceptive system for certain types of visual organization.


Assuntos
Estética , Fractais , Processamento de Imagem Assistida por Computador , Inquéritos e Questionários
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