The role of melatonin on sperm function as well as its use as antioxidant for sperm conservation is analysed in this review. Melatonin has been included in the cooling/freezing media for the conservation of spermatozo...The role of melatonin on sperm function as well as its use as antioxidant for sperm conservation is analysed in this review. Melatonin has been included in the cooling/freezing media for the conservation of spermatozoa. Depending on the animal species, the best dose to improve sperm quality and fertile capacity is in the range from 0.01 mM to 3.00 mM. Since the work started on the use of melatonin as antioxidant for the conservation of spermatozoa (2011), a search for references was done on the subject using internet and our university libraries: journals, proceedings, thesis,etc. The search focused on animal spermatozoa, but a collection of papers on human spermatozoa was also carried out.展开更多
Land cover change can lead to slope instability by accelerating erosive processes associated with agriculture, forestry, and infrastructure. The Rio Chiquito-Barranca del Muerto subbasin has experienced an increase in...Land cover change can lead to slope instability by accelerating erosive processes associated with agriculture, forestry, and infrastructure. The Rio Chiquito-Barranca del Muerto subbasin has experienced an increase in land cover change due to government programs and the establishment of agricultural and urban areas. The aim of this study was to provide a model to map the susceptibility to gravitational processes along sites where anthropogenic land cover change has occurred.The method was based on the stratification of the subbasin according to landforms and cartographic variables. These variables were used in a multicriteria assessment to assign weights according to their contribution to the onset of new gravitational processes. Those weights were used to create a susceptibility map based on a weighted linear sum.The accuracy of the resulting map was validated in an error matrix with a random stratified design based on susceptibility classes per landform. The results produced a map of areas with susceptibility to gravitational processes due to land cover change; this susceptibility is very high in the undifferentiated pyroclastic slope and limestone mountain, where it derives not only from anthropogenic effects on natural vegetation cover, but also from steep slopes,weathered materials, low apparent density, high erosivity, and previous gravitational processes. The results support other studies that concluded that loss of vegetation is a triggering factor in the formation of gravitational processes, but also show that excessive reforestation can increase gravitational processes.展开更多
文摘The role of melatonin on sperm function as well as its use as antioxidant for sperm conservation is analysed in this review. Melatonin has been included in the cooling/freezing media for the conservation of spermatozoa. Depending on the animal species, the best dose to improve sperm quality and fertile capacity is in the range from 0.01 mM to 3.00 mM. Since the work started on the use of melatonin as antioxidant for the conservation of spermatozoa (2011), a search for references was done on the subject using internet and our university libraries: journals, proceedings, thesis,etc. The search focused on animal spermatozoa, but a collection of papers on human spermatozoa was also carried out.
基金PAPIIT IN102115 projectprogram Basic Science SEP-CONACYT(167495)+1 种基金CONACYT scholarship program(328294)Postgraduate Program in Geography,UNAM
文摘Land cover change can lead to slope instability by accelerating erosive processes associated with agriculture, forestry, and infrastructure. The Rio Chiquito-Barranca del Muerto subbasin has experienced an increase in land cover change due to government programs and the establishment of agricultural and urban areas. The aim of this study was to provide a model to map the susceptibility to gravitational processes along sites where anthropogenic land cover change has occurred.The method was based on the stratification of the subbasin according to landforms and cartographic variables. These variables were used in a multicriteria assessment to assign weights according to their contribution to the onset of new gravitational processes. Those weights were used to create a susceptibility map based on a weighted linear sum.The accuracy of the resulting map was validated in an error matrix with a random stratified design based on susceptibility classes per landform. The results produced a map of areas with susceptibility to gravitational processes due to land cover change; this susceptibility is very high in the undifferentiated pyroclastic slope and limestone mountain, where it derives not only from anthropogenic effects on natural vegetation cover, but also from steep slopes,weathered materials, low apparent density, high erosivity, and previous gravitational processes. The results support other studies that concluded that loss of vegetation is a triggering factor in the formation of gravitational processes, but also show that excessive reforestation can increase gravitational processes.
