ABSTRACT
Coastal zones are usually composed of coastlines and coastal wetlands and are among the most productive and dynamic ecosystems. However, the deltas are seldom detected and compared in detail at the continental scale to investigate the spatiotemporal evolution of coastline migration and coastal wetlands. Here we detected and compared the spatiotemporal changes in coastlines, wetlands, and ecosystem services in major deltas in Asia, including the Yellow River Delta (YRD), Yangtze River Delta (YAD), Pearl River Delta (PRD), Red River Delta (RRD), Mekong River Delta (MERD), Chao Phraya River Delta (CPRD), Mahanadi River Delta (MARD), Krishna River Delta (KRD), and Indus River Delta (IRD). We used time series remote sensing images from 1990 to 2019 to derive coastline and wetland information for the nine coastal zones. The ecosystem service value coefficients were applied to explore the ecosystem services characteristics of wetland changes in coastal areas. We found that the coastlines of the deltas in the study area changed less in the bedrock and sandy coasts, while the coastlines in the silty delta coasts changed more from 1990 to 2019. The interannual dynamics of coastal wetland areas in nine major deltas over the nearly 30 years can be divided into three periods: decreasing variability (1990-2005), increasing variability (2005-2015), and increasing volatility (2015-2019). Ecosystem services had an overall downward trend. These findings complement the official database of coastal planning and have substantial guiding implications for adjusting coastal management regulation policies.
Subject(s)
Ecosystem , Wetlands , Rivers , Asia , ChinaABSTRACT
The aim of this study was to evaluate the effect of soft tissue thickness of upper lip on lip retraction in orthodonticaltreated females and identify the ratio of maxillary incisor retraction to upper lip retraction. Pre- and post-treatment lateral cephalograms of 100 adults were examined to measure the lip thickness in upper lip and establish the classification standard. All subjects were treated with 4 first premolar extractions followed by upper central incisors retraction. Pre- and post-treatment lateral cephalograms of 19 patients were reviewed to determine the changes of the upper lip and incisor positions through landmarks displacement. An independent-samples t test and one-way analysis of variance were performed. The correlations between maxillary incisor retraction and upper lip retraction were explored by the Pearson correlation method. P-values<0.05 were considered statistically significant. The lip thickness of adult male patients was greater than that of adult female patients. The average ratio of maxillary incisor retraction to upper lip repositioning was 1.6:1,1.9:1 and 2.2:1 in the thin lips group, normal lips group and thick lips group, respectively. Gender differences exist in the thickness of upper lip. Horizontal changes of the maxillary incisor showed a significant correlation to horizontal changes of the upper lip (P<0.001).There were negative correlations between the thickness of upper lip and the ratio between change in maxillary incisor protrusion and change in upper lip protrusion.
El objetivo de este estudio fue evaluar el efecto del grosor de los tejidos blandos del labio superior, sobre la retracción del labio en mujeres tratadas con ortodoncia e identificar la proporción de retracción del diente incisivo maxilar con respecto a la retracción del labio superior. Se examinaron cefalogramas laterales, previos y posteriores al tratamiento de 100 adultos, para medir el grosor del labio superior y establecer un estándar de clasificación. Todos los sujetos fueron tratados con 4 extracciones de los primeros premolares seguidas de retracción de los incisivos centrales superiores. Se revisaron los cefalogramas laterales, previos y posteriores al tratamiento de 19 pacientes, para determinar los cambios del labio superior y las posiciones de los incisivos a través del desplazamiento de los puntos de referencia. Se realizó una prueba t de muestras independientes y un análisis de varianza de una vía. Las correlaciones entre la retracción del incisivo maxilar y la retracción del labio superior se exploraron mediante el método de correlación de Pearson. Los valores de p<0,05 fueron considerados estadísticamente significativos. El grosor de los labios de los pacientes adultos masculinos fue mayor que el de las pacientes adultas. La relación promedio de la retracción del incisivo maxilar al reposicionamiento del labio superior fue de 1,6:1,1; 9:1 y 2,2:1 en el grupo de labios delgados, grupo de labios normales y grupo de labios gruesos, respectivamente. Existen diferencias de sexo en el grosor del labio superior. Los cambios horizontales del incisivo maxilar mostraron una correlación significativa con los cambios horizontales del labio superior (P<0,001). Hubo correlaciones negativas entre el grosor del labio superior y la relación entre el cambio en la protuberancia del incisivo maxilar y el cambio en la protrusión del labio superior.