Search results for "Sound"

Estudio de fracciones en contextos sonoros

2016

En este ensayo resaltamos los vínculos cognitivos entre las matemáticas y la música, que pueden favorecer procesos de enseñanza y aprendizaje de las fracciones en la matemática escolar. Las actividades exhibidas provienen de una investigación que promueve experiencias sensoriales en el campo rítmico para favorecer la construcción de nociones matemáticas. Dichas actividades posibilitan un engranaje armónico entre las matemáticas y la música convergentes en el tiempo y el sonido como los objetos de estudio común entre éstas disciplinas. El análisis de la investigación que aquí reportamos es producto de la aplicación de las actividades en diferentes programas de formación de profesorado de Méx…

Application of ultrasound as clean technology for extraction of specialized metabolites from stinging nettle (Urtica dioica L.)

2022

Nettle is a highly valued medicinal plant that is still largely neglected, both in terms of nutrition and use for pharmacological purposes. Tinctures, i.e., alcoholic extracts, are becoming increasingly popular nettle products, mainly because they allow better availability of phytochemicals and their stability over a longer period of time. The production of alcoholic extracts is a chemically demanding process that is still usually carried out using conventional techniques, which have numerous drawbacks. The use of green technologies such as ultrasound-assisted extraction (UAE), which is characterized by high efficiency of phytochemical extraction, shorter treatment time, and a much lower en…

Classification of Heart Sounds Using Convolutional Neural Network

2020

Heart sounds play an important role in the diagnosis of cardiac conditions. Due to the low signal-to-noise ratio (SNR), it is problematic and time-consuming for experts to discriminate different kinds of heart sounds. Thus, objective classification of heart sounds is essential. In this study, we combined a conventional feature engineering method with deep learning algorithms to automatically classify normal and abnormal heart sounds. First, 497 features were extracted from eight domains. Then, we fed these features into the designed convolutional neural network (CNN), in which the fully connected layers that are usually used before the classification layer were replaced with a global averag…

Ultrasonic mensuration of fetal limb bones in the second and third trimesters

1987

Growth of fetal limb bones has been examined in a prospective cross-sectional study in 530 patients between 13 and 42 weeks of gestation by ultrasound. The length of the femur, tibia, humerus, and radius were measured in all cases, and fibula and ulna in 393 cases. For each week of gestation mean lengths (+/- 2 standard deviations) were calculated. All limb bones showed linear growth from 13 weeks to 25 weeks of gestation, after which the growth curve appeared nonlinear. A strong linear relationship (r greater than 0.98) between the BPD and bone length was found for each bone. In five aborted fetuses, prenatal sonographic measurements of the ossified diaphyses were compared with the postnat…

Value of the electronic scalpel (cut mode) in the evaluation of the fetal face

2000

Objectives To evaluate the improvement of image quality and diagnostic value of fetal face examinations using the electric scalpel. Methods A total of 232 cases were examined. The fetuses were separated into two groups: Group A, including normal fetuses (n = 152) and Group B, fetuses with facial pathology (n = 80). The fetuses were divided into eight subgroups according to gestational age (9–12 weeks, 13–16 weeks, 17–20 weeks, 21–24 weeks, 25–28 weeks, 29–32 weeks, 33–36 weeks and 37–40 weeks). Results The number of cutting steps for the improvement of image quality ranged from 1 to 9 (mean value 3) in the group of normal fetuses and from 1 to 10 (mean value 3) in the group of fetuses with …

An anatomical fetal brain structure and a normal variant mimicking anomalies on routine neurosonographic imaging: report of two cases

2004

We present two cases in which an anatomical structure, the calcar avis, and a normal variant, a bifid choroid plexus, mimicked abnormalities on routine prenatal ultrasound examination. To the best of our knowledge these pitfalls have only been described in neonates. A familiarity with these false images is important to avoid erroneous diagnoses.

Biometry of the fetal corpus callosum by three-dimensional ultrasound

2013

Objectives To construct reference ranges of quantitative characteristics of the fetal corpus callosum. Methods Women referred to a tertiary center for sonographic examination were recruited to undergo a detailed fetal scan from 17 to 41 weeks of gestation. Three-dimensional (3D) sonographic volumes of normal fetal brains were acquired and analyzed offline. We obtained three different measurements of the corpus callosal length, as well as the height (/thickness) of its segments, namely the rostrum, genu, body and splenium. Results Initially we recruited 604 pregnant women, of whom 138 were excluded because of various disorders/abnormalities, multiple pregnancy or gestational age < 18 weeks. …

Entwicklung eines Wachstumsmodells für fetale Kopf- und Rumpfmaße

1987

Head parameters BPD, FOD and HC and abdomen parameters ATD, APD and AC have been ascertained in a prospective cross-sectional study in 515 healthy single fetuses between 13 and 40 weeks of gestation by ultrasound. In all cases ultrasound velocity was 1540 m/sec. From these data, a growth model was achieved for each parameter and corresponding growth curves with 5%, 10%, 50%, 90% and 95% percentiles were established.

P01.46: The incidence and characteristics of first-trimester fetal lateral neck cysts

2006

Application of transvaginal and abdominal three-dimensional ultrasound for the detection or exclusion of malformations of the fetal face

1997

In a total of 618 pregnant women between 9 and 37 weeks' gestation, the fetal face was evaluated by two-dimensional and three-dimensional ultrasound imaging as part of a level III screening evaluation for fetal anomalies. A three-dimensional endovaginal probe (5 MHz) was used for examinations at between 9 and 15 weeks, and an abdominal three-dimensional probe (3.5 MHz) was used after 15 weeks. Three different three-dimensional image display modes were employed: (1) the orthogonal display; (2) the surface display; and (3) the transparent display. When we studied the three-dimensional orthogonal displays in 125 cases evaluated by abdominal ultrasound, we found that the facial profile shown in…