By introducing a knowledge production function which combines both foreign technology imports and domestic research and development （R＆D） expenditure into an endogenous technological progress model, this paper exam...By introducing a knowledge production function which combines both foreign technology imports and domestic research and development （R＆D） expenditure into an endogenous technological progress model, this paper examines the mechanism that determines enterprises＇ R＆D intensity in developing countries, and explores how factors such as technological gap, technology absorptive capacity, innovation environment and innovation ability would impact Chinese enterprises＇decision made on R＆D intensity. Our results suggest that technological gap has no significant single impact on enterprises＇R＆D intensity, but rather influences enterprises＇decision on R＆D jointly with other factors such as degree of openness and human capital. A relative fall in efficiency of technology imitation recently has a negative effect on total R＆D intensity but helps to promote enterprises＇ independent R＆D. In addition, among factors related to R＆D innovation environment, industrial R＆D intensity has a significantly positive impact on enterprises＇ independent R＆D intensity, while regional economies of scale, proportion of large enterprises and proportion of government R＆D investment have some certain negative impacts.展开更多
Objective:The aim of this study is to compare the effect of Vitamin D and Vitamin E supplementations,alone,and in combination,on reducing the intensity and duration of dysmenorrhea in women who were referred to the Ko...Objective:The aim of this study is to compare the effect of Vitamin D and Vitamin E supplementations,alone,and in combination,on reducing the intensity and duration of dysmenorrhea in women who were referred to the Kowsar gynecological clinics of Shahid Motahari Hospital of Urmia University of Medical Sciences.Materials and Methods:A double-blinded clinical trial was conducted on 112 women with dysmenorrhea who were randomly allocated into the four study groups.Finally,100 women complete the study and received capsules containing a placebo(n=25),1000 IU of Vitamin D(n=25),400 mg of Vitamin E(n=25),and 1000 IU of Vitamin D+400 mg of Vitamin E(n=25)every 24 h for 2 consecutive months at the beginning of the menstrual period.The pain intensity and duration among groups were compared before and after the intervention.Results:The mean menstrual pain duration in all three experimental groups(Vitamin E,Vitamin D,and the combination of them)was lower than the placebo group(all P<0.05),and the mean pain intensity scores in all three experimental groups were significantly lower than the placebo group(all P<0.05).The results(means)for all of the drugs administered at the end of the 2nd month were better than the 1st month(all P<0.01).Conclusions:Vitamin E and Vitamin D,as well as their combination,are recommended as an effective and safe treatment for the management of the complications of dysmenorrhea.展开更多
This paper examines the effects of ownership types on firms＇ R＆D intensity and innovation performance, using a sample of 357,857 Chinese firms from 2005-2007. This study finds considerable divergence among Chinese d...This paper examines the effects of ownership types on firms＇ R＆D intensity and innovation performance, using a sample of 357,857 Chinese firms from 2005-2007. This study finds considerable divergence among Chinese domestic enterprises in terms of R＆D intensity and innovation performance. Firms owned by the central government are the key drivers for firms＇ R＆D activities, while local government, private and foreign ownerships are negatively related to both R＆D intensity and innovation performance. Significant divergence within government ownership category and argues that China＇s institutional changes generate varied government ownership groups with different levels of resource endowment, which in turn influence firms＇ R＆D activities.展开更多
Airblasts,as one common phenomenon accompanied by rapid movements of landslides or rock/snow avalanches,commonly result in catastrophic damages and are attracting more and more scientific attention.To quantitatively a...Airblasts,as one common phenomenon accompanied by rapid movements of landslides or rock/snow avalanches,commonly result in catastrophic damages and are attracting more and more scientific attention.To quantitatively analyze the intensity of airblast initiated by landslides,the Wangjiayan landslide,occurred in the Wenchuan earthquake,is selected here with the landslide propagation and airblast evolution being studied using FLUENT by introducing the Voellmy rheological law.The results reveal that:(1)For the Wangjiayan landslide,its whole travelling duration is only 12 s with its maximum velocity reaching 36 m/s at t=10 s;(2)corresponding to the landslide propagation,the maximum velocity,28 m/s,of the airblast initiated by the landslide also appears at t=10 s with its maximum pressure reaching594.8 Pa,which is equivalent to violent storm;(3)under the attack of airblast,the load suffered by buildings in the airblast zone increases to 1300 Pa at t=9.4 s and sharply decreased to-7000 Pa as the rapid decrease of the velocity of the sliding mass at t=10 s,which is seriously unfavorable for buildings and might be the key reason for the destructive collapse of buildings in the airblast zone of the Wangjiayan landslide.展开更多
The Gouméré region is located in the North-East of Côte d’Ivoire and is located in the South-West of the Bui furrow. In order to highlight the geology of the area studied, 14 samples were taken for stu...The Gouméré region is located in the North-East of Côte d’Ivoire and is located in the South-West of the Bui furrow. In order to highlight the geology of the area studied, 14 samples were taken for studies using petrographic, geochemical and metallogenic methods. The study of macroscopic and microscopic petrography made it possible to highlight two major lithological units: 1) a volcano-plutonic unit, formed of gabbros, basalt, volcaniclastics and rhyodacite;2) a sedimentary unit (microconglomerate). From a geochemical point of view, the results obtained indicate that the plutonites are gabbro and gabbro diorite while the volcanics have compositions of basaltic andesites, rhyolite and dacites. The sediments have a litharenitic to sublitharenitic character. The metallogenic study made it possible to highlight hydrothermal alterations and metalliferous paragenesis on the formations studied. Hydrothermal alteration is characterized by the presence of carbonation, silicification, sericitization, sulfidation and to a lesser degree chloritization. Metalliferous paragenesis consists of pyrite, chalcopyrite, hematite and magnetite.展开更多
Climate change is an alarming global challenge, particularly affecting the least developed countries (LDCs) including Liberia. These countries, located in regions prone to unpredictable temperature and precipitation c...Climate change is an alarming global challenge, particularly affecting the least developed countries (LDCs) including Liberia. These countries, located in regions prone to unpredictable temperature and precipitation changes, are facing significant challenges, particularly in climate-sensitive sectors such as mining and agriculture. LDCs need more resilience to adverse climate shocks but have limited capacity for adaptation compared to other developed and developing nations. This paper examines Liberia’s susceptibility to climate change as a least developed country, focusing on its exposure, sensitivity, and adaptive capacity. It provides an overview of LDCs and outlines the global distribution of carbon dioxide emissions. The paper also evaluates specific challenges that amplify Liberia’s vulnerability and constrain sustainable adaptation, providing insight into climate change’s existing and potential effects. The paper emphasizes the urgency of addressing climate impacts on Liberia and calls for concerted local and international efforts for effective and sustainable mitigation efforts. It provides recommendations for policy decisions and calls for further research on climate change mitigation and adaptation.展开更多
基金This study has been supported by “Research on Chinese Enterprises＇ R＆D Efficiency and Its Influencing Factors” under National Natural Science Foundation of China （70902002）, “Research on Beijing Enterprises＇ R＆D Efficiency and Its Influencing Factors： Analysis Based on Cutting-edge” under Beijing Natural Science Foundation （9102019）, together with “Program for New Century Excellent Talents in University” under the Ministry of Education and Key Project under the “211 Project” for Central University of Finance and Economics.
文摘By introducing a knowledge production function which combines both foreign technology imports and domestic research and development （R＆D） expenditure into an endogenous technological progress model, this paper examines the mechanism that determines enterprises＇ R＆D intensity in developing countries, and explores how factors such as technological gap, technology absorptive capacity, innovation environment and innovation ability would impact Chinese enterprises＇decision made on R＆D intensity. Our results suggest that technological gap has no significant single impact on enterprises＇R＆D intensity, but rather influences enterprises＇decision on R＆D jointly with other factors such as degree of openness and human capital. A relative fall in efficiency of technology imitation recently has a negative effect on total R＆D intensity but helps to promote enterprises＇ independent R＆D. In addition, among factors related to R＆D innovation environment, industrial R＆D intensity has a significantly positive impact on enterprises＇ independent R＆D intensity, while regional economies of scale, proportion of large enterprises and proportion of government R＆D investment have some certain negative impacts.
文摘Objective:The aim of this study is to compare the effect of Vitamin D and Vitamin E supplementations,alone,and in combination,on reducing the intensity and duration of dysmenorrhea in women who were referred to the Kowsar gynecological clinics of Shahid Motahari Hospital of Urmia University of Medical Sciences.Materials and Methods:A double-blinded clinical trial was conducted on 112 women with dysmenorrhea who were randomly allocated into the four study groups.Finally,100 women complete the study and received capsules containing a placebo(n=25),1000 IU of Vitamin D(n=25),400 mg of Vitamin E(n=25),and 1000 IU of Vitamin D+400 mg of Vitamin E(n=25)every 24 h for 2 consecutive months at the beginning of the menstrual period.The pain intensity and duration among groups were compared before and after the intervention.Results:The mean menstrual pain duration in all three experimental groups(Vitamin E,Vitamin D,and the combination of them)was lower than the placebo group(all P<0.05),and the mean pain intensity scores in all three experimental groups were significantly lower than the placebo group(all P<0.05).The results(means)for all of the drugs administered at the end of the 2nd month were better than the 1st month(all P<0.01).Conclusions:Vitamin E and Vitamin D,as well as their combination,are recommended as an effective and safe treatment for the management of the complications of dysmenorrhea.
基金This research is supported by National Natural Science Foundation of China （No. 71373010）.
文摘This paper examines the effects of ownership types on firms＇ R＆D intensity and innovation performance, using a sample of 357,857 Chinese firms from 2005-2007. This study finds considerable divergence among Chinese domestic enterprises in terms of R＆D intensity and innovation performance. Firms owned by the central government are the key drivers for firms＇ R＆D activities, while local government, private and foreign ownerships are negatively related to both R＆D intensity and innovation performance. Significant divergence within government ownership category and argues that China＇s institutional changes generate varied government ownership groups with different levels of resource endowment, which in turn influence firms＇ R＆D activities.
基金supported by the National Natural Science Foundation of China(42322702,42177131)。
文摘Airblasts,as one common phenomenon accompanied by rapid movements of landslides or rock/snow avalanches,commonly result in catastrophic damages and are attracting more and more scientific attention.To quantitatively analyze the intensity of airblast initiated by landslides,the Wangjiayan landslide,occurred in the Wenchuan earthquake,is selected here with the landslide propagation and airblast evolution being studied using FLUENT by introducing the Voellmy rheological law.The results reveal that:(1)For the Wangjiayan landslide,its whole travelling duration is only 12 s with its maximum velocity reaching 36 m/s at t=10 s;(2)corresponding to the landslide propagation,the maximum velocity,28 m/s,of the airblast initiated by the landslide also appears at t=10 s with its maximum pressure reaching594.8 Pa,which is equivalent to violent storm;(3)under the attack of airblast,the load suffered by buildings in the airblast zone increases to 1300 Pa at t=9.4 s and sharply decreased to-7000 Pa as the rapid decrease of the velocity of the sliding mass at t=10 s,which is seriously unfavorable for buildings and might be the key reason for the destructive collapse of buildings in the airblast zone of the Wangjiayan landslide.
文摘The Gouméré region is located in the North-East of Côte d’Ivoire and is located in the South-West of the Bui furrow. In order to highlight the geology of the area studied, 14 samples were taken for studies using petrographic, geochemical and metallogenic methods. The study of macroscopic and microscopic petrography made it possible to highlight two major lithological units: 1) a volcano-plutonic unit, formed of gabbros, basalt, volcaniclastics and rhyodacite;2) a sedimentary unit (microconglomerate). From a geochemical point of view, the results obtained indicate that the plutonites are gabbro and gabbro diorite while the volcanics have compositions of basaltic andesites, rhyolite and dacites. The sediments have a litharenitic to sublitharenitic character. The metallogenic study made it possible to highlight hydrothermal alterations and metalliferous paragenesis on the formations studied. Hydrothermal alteration is characterized by the presence of carbonation, silicification, sericitization, sulfidation and to a lesser degree chloritization. Metalliferous paragenesis consists of pyrite, chalcopyrite, hematite and magnetite.
文摘Climate change is an alarming global challenge, particularly affecting the least developed countries (LDCs) including Liberia. These countries, located in regions prone to unpredictable temperature and precipitation changes, are facing significant challenges, particularly in climate-sensitive sectors such as mining and agriculture. LDCs need more resilience to adverse climate shocks but have limited capacity for adaptation compared to other developed and developing nations. This paper examines Liberia’s susceptibility to climate change as a least developed country, focusing on its exposure, sensitivity, and adaptive capacity. It provides an overview of LDCs and outlines the global distribution of carbon dioxide emissions. The paper also evaluates specific challenges that amplify Liberia’s vulnerability and constrain sustainable adaptation, providing insight into climate change’s existing and potential effects. The paper emphasizes the urgency of addressing climate impacts on Liberia and calls for concerted local and international efforts for effective and sustainable mitigation efforts. It provides recommendations for policy decisions and calls for further research on climate change mitigation and adaptation.
