In recent years, the incidence of placenta previa has been increasing. According to the literature, it is mainly related to induced labor, artificial abortion, cesarean section, high aging pregnancy, multipara or smok...In recent years, the incidence of placenta previa has been increasing. According to the literature, it is mainly related to induced labor, artificial abortion, cesarean section, high aging pregnancy, multipara or smoking. The placenta previa is the chief cause of bleeding in late pregnancy and threatens the lives of mother and infant, resulting in a high risk problem in obstetrics. This article studies 322 cases of placenta previa from my hospital and Dalian Obstetrics and Gynecological Hospital from January, 2002 to July, 2009, on the basis of clinicretrospective analysis, in order to deepen our understanding and art of treating placenta previa. The study revealed that: 1. With 322 cases of placenta previa, the incidence was 0.73%. It was higher than the incidence 0.3% reported abroad and lower than the incidence 0.94% reported in our country. The data were from sampling survey and did not prove relations between placenta previa and ages, different from the result obtained abroad in which placenta previa had relation with pregnancy ages. The outcome needs further study. But artificial abortion, induced labor, cesarean section and multipara clearly influence the incidence. The study did not analyze the relation between smoking and placenta previa, but there was external data proving that smoking was related to placenta previa; 2. Ultrasound-B is a better method for examination at present; 3. In cases of vaginal childbirth there was a higher incidence of lateral placenta previa and partial placenta previa. The conservative temporization and timely cesarean section can greatly decrease the mortality of mother and infant.展开更多
The choice of employment destination is the basis of migrant workers＇ spatial flow, the study on the choice of employment destination is helpful to understand the spatial law of migrant workers＇ flow from a micro pe...The choice of employment destination is the basis of migrant workers＇ spatial flow, the study on the choice of employment destination is helpful to understand the spatial law of migrant workers＇ flow from a micro perspective. Through the case study on 11 sample villages generated by the random stratified sampling in Henan Province, authors of this paper find that the distribution of destinations is dispersed in a large area while concentrated in certain places. Most of the destinations are in counties and outside Henan Province. Migrant workers are mainly concentrated in the economically more developed eastern provinces. The central, though a big source of migrant workers, has not formed a core employment area for migrant workers. The main factors influencing migrant workers＇ choice of employment distances include age, family size, per capita arable land, the village＇s economic development level, the village terrain, transportation, its distance from the nearest city, and workers＇ relationship networks. From the perspective of employment destinations, on a provincial scale, the employment attraction coefficient based on the destination＇s level of economic development and the employment distance, efficiently explains farmers＇ choice of destinations, that is, destinations with a more developed economy and a shorter employment distance are the top choice for migrant workers.展开更多
文摘In recent years, the incidence of placenta previa has been increasing. According to the literature, it is mainly related to induced labor, artificial abortion, cesarean section, high aging pregnancy, multipara or smoking. The placenta previa is the chief cause of bleeding in late pregnancy and threatens the lives of mother and infant, resulting in a high risk problem in obstetrics. This article studies 322 cases of placenta previa from my hospital and Dalian Obstetrics and Gynecological Hospital from January, 2002 to July, 2009, on the basis of clinicretrospective analysis, in order to deepen our understanding and art of treating placenta previa. The study revealed that: 1. With 322 cases of placenta previa, the incidence was 0.73%. It was higher than the incidence 0.3% reported abroad and lower than the incidence 0.94% reported in our country. The data were from sampling survey and did not prove relations between placenta previa and ages, different from the result obtained abroad in which placenta previa had relation with pregnancy ages. The outcome needs further study. But artificial abortion, induced labor, cesarean section and multipara clearly influence the incidence. The study did not analyze the relation between smoking and placenta previa, but there was external data proving that smoking was related to placenta previa; 2. Ultrasound-B is a better method for examination at present; 3. In cases of vaginal childbirth there was a higher incidence of lateral placenta previa and partial placenta previa. The conservative temporization and timely cesarean section can greatly decrease the mortality of mother and infant.
文摘The choice of employment destination is the basis of migrant workers＇ spatial flow, the study on the choice of employment destination is helpful to understand the spatial law of migrant workers＇ flow from a micro perspective. Through the case study on 11 sample villages generated by the random stratified sampling in Henan Province, authors of this paper find that the distribution of destinations is dispersed in a large area while concentrated in certain places. Most of the destinations are in counties and outside Henan Province. Migrant workers are mainly concentrated in the economically more developed eastern provinces. The central, though a big source of migrant workers, has not formed a core employment area for migrant workers. The main factors influencing migrant workers＇ choice of employment distances include age, family size, per capita arable land, the village＇s economic development level, the village terrain, transportation, its distance from the nearest city, and workers＇ relationship networks. From the perspective of employment destinations, on a provincial scale, the employment attraction coefficient based on the destination＇s level of economic development and the employment distance, efficiently explains farmers＇ choice of destinations, that is, destinations with a more developed economy and a shorter employment distance are the top choice for migrant workers.
