A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions,...A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions, the mechanisms associated with fathers＇ structural characteristics of work that produce divergent labor market outcomes are less well understood. The authors leveraged the cases of productivity and specialization, family and responsibility, and compensating differentials and examined the impacts of work context and occupational characteristics on the pay gap between fathers and non-fathers Based on joint data from the 1997-2015 National Longitudinal Survey of Youth （NLSY97） and Occupational Information Network （O＇NET） （n -- 37,138）, the authors used fixed-effects models to estimate the associations between job features and the fatherhood premium. The regression results showed that occupations entailing competition and requiring on-the-job training are associated with more wage bonus; occupations offering inflexible schedule are associated with less wage gain These work-related characteristics further emphasize fathers＇ work structure and context, human capital accumulation, and work-family conflict. Overall, these findings are consistent with the theoretical perspectives of productivity and specialization and compensating differentials, adding new evidences to the structural explanations of the fatherhood premium.展开更多
Calopogonium mucunoides （calopo） is one of forage legumes as protein and mineral sources for ruminant livestock in the tropics. However, most of the land in Indonesia that used for forage crops production characteri...Calopogonium mucunoides （calopo） is one of forage legumes as protein and mineral sources for ruminant livestock in the tropics. However, most of the land in Indonesia that used for forage crops production characterized by acid pH, low in nitrogen and phosphorus. Phosphorus fertilizers have been used widely to improve soil fertility in Indonesia. As the high cost of superphosphate （SP）, the focus is now on rock phosphate （RP） fertilizer which relatively cheaper than SP, and it has high solubility in acid condition. Combination between nitrogen and phosphorus fertilizer from difference sources may be a promising technique to overcome those problems. A field experiment was conducted on a latosolic soil （low pH, nitrogen and low available Bray II extractable P）. The objective of the research is to evaluate the effect of combination between nitrogen and phosphorus fertilizer from difference sources on dry matter production and digestibility, nitrogen and phosphorus uptake of Calopogonium mucunoides （calopo）. Completely randomized block design with 9 treatments in 3 replicates was used in this experiment. The treatments were TO （control）, TI （SP）, T2 （RP）, T3 （urea）, T4 （ZA）, T5 （SP ＋ urea）, T6 （SP ＋ ZA）, T7 （RP ＋ urea）, T8 （RP ＋ ZA）. Size of plot was 2 m × 3 m, fertilized with 50 kg N/ha and 200 kg P2O5/ha, according to the assigned treatment. All plot received basal fertilizer of KCI （100 kg KzO/ha） and goat manure （5 ton/ha）. Calopogonium mucunoides was defoliated and nutritive value. Result showed that dry matter production on 90 days after planting and analyzed for dry matter production and nutritive value significantly influenzed by the treatments. Combination between N （ZA, urea） and P （SP, RP） fertilizer resulted dry matter production, nutrient uptake, and dry matter digestibility significantly higher compared to control, and NP fertilization separatedly. Combination of RP and N （urea, ZA） resulted in dry matter production, nutrient uptake, and dry matter digestibility non-significantly different compared to SP in combination with N （urea, ZA）. Therefore, RP could replace SP if combined with urea or ZA to increase production and nutritive value of Calopogonium mucunoides in acid latosolic soil.展开更多
Microalgae lipids/oils are a promising feedstock for biodiesel production. The desired lipids are triacylglycerols. These can either be transesterified to biodiesel or decarboxylated to ＂green diesel＂. Increasing mi...Microalgae lipids/oils are a promising feedstock for biodiesel production. The desired lipids are triacylglycerols. These can either be transesterified to biodiesel or decarboxylated to ＂green diesel＂. Increasing microalgae lipids production by thermal stressing is important in improving the economics of biodiesel production, but its effectiveness needs to be determined. This paper focuses on the effect of cooling stressing lipid triggering on the microalgae production and lipids yield. Two microalgae species were studied, Chlorella sp. and Dunaliella. In each case, microalgae were grown in two identical 2 L PBRs （photobiorectors） at room temperature. At the end of the exponential growth phase, one PBR was placed in a cold environment while the other PBR was left at room temperature. Microalgae was harvested, freeze dried and the algae oil was extracted. Measurements show that cooling stressing slightly increased the biomass of algae （11% for C2 and 13% for Dunaliella）, but it decreased the lipids content of the microalgae, 62% for Chlorella sp. and 13% for Dunaliella. The net effect is a decrease in the lipid production rate （mg lipid/L-day） 58% in case of Chlorella sp., and 2% in case of Dunaliella.展开更多
Animal nutrition is one of the most important limiting factors in animal production, especially in ruminants, providing proteins being the main constraint, due to the limited availability and high cost of protein sour...Animal nutrition is one of the most important limiting factors in animal production, especially in ruminants, providing proteins being the main constraint, due to the limited availability and high cost of protein sources （oilseed meals）. Currently in the dam ＂El lnfiernillo＂ in Michoacan Mexico, has a large population of devil fish （Pterygoplichthys spp.）, which is an economic and ecological problem, because it is not consumed by humans and causes pollution to be discarded directly into the environment. For that reason the objective of this study was to evaluate the use of silage acid devil fish （SADF） in fattening beef cattle as a protein supplement. SADF is defined as a product semi-liquid or pasty mixed with formic acid, which leads to a decrease in pH to near 4.0. Used 18 young bulls （Bos taurus × Bos indicus） for 60 days with a starting weight of 278.9 ± 51.2 kg, housed in individual pens with food and water ad libitum were randomly assigned to three treatments with different levels of inclusion SADF （0%, 12% and 18%）. They were weighed to the beginning of the experiment and later every 30 days, previous fasting of 24 hours. To determine the food consumption, weigh every day the offered food and the surplus. There were no significant differences （P 〈 0.05） among treatments with different levels of inclusion of SADF with respect to daily weight gain, with values of 952 ± 324, 927 ±322 and 854 ± 307 g/day, respectively. The dry matter intake （DMI） was 8.9, 9.3 and 7.7 kg/day to 0%, 12% and 18% of SADF, respectively. In the same values for feed conversion were 9.34, 10.03 and 9.01 kg DMI/kg of weigh live, and carcass yield of 60.6%, 60.3% and 58.5%, respectively. It is concluded that fish silage acid devil is an excellent alternative in feeding beef cattle as a protein supplement.展开更多
文摘A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions, the mechanisms associated with fathers＇ structural characteristics of work that produce divergent labor market outcomes are less well understood. The authors leveraged the cases of productivity and specialization, family and responsibility, and compensating differentials and examined the impacts of work context and occupational characteristics on the pay gap between fathers and non-fathers Based on joint data from the 1997-2015 National Longitudinal Survey of Youth （NLSY97） and Occupational Information Network （O＇NET） （n -- 37,138）, the authors used fixed-effects models to estimate the associations between job features and the fatherhood premium. The regression results showed that occupations entailing competition and requiring on-the-job training are associated with more wage bonus; occupations offering inflexible schedule are associated with less wage gain These work-related characteristics further emphasize fathers＇ work structure and context, human capital accumulation, and work-family conflict. Overall, these findings are consistent with the theoretical perspectives of productivity and specialization and compensating differentials, adding new evidences to the structural explanations of the fatherhood premium.
文摘Calopogonium mucunoides （calopo） is one of forage legumes as protein and mineral sources for ruminant livestock in the tropics. However, most of the land in Indonesia that used for forage crops production characterized by acid pH, low in nitrogen and phosphorus. Phosphorus fertilizers have been used widely to improve soil fertility in Indonesia. As the high cost of superphosphate （SP）, the focus is now on rock phosphate （RP） fertilizer which relatively cheaper than SP, and it has high solubility in acid condition. Combination between nitrogen and phosphorus fertilizer from difference sources may be a promising technique to overcome those problems. A field experiment was conducted on a latosolic soil （low pH, nitrogen and low available Bray II extractable P）. The objective of the research is to evaluate the effect of combination between nitrogen and phosphorus fertilizer from difference sources on dry matter production and digestibility, nitrogen and phosphorus uptake of Calopogonium mucunoides （calopo）. Completely randomized block design with 9 treatments in 3 replicates was used in this experiment. The treatments were TO （control）, TI （SP）, T2 （RP）, T3 （urea）, T4 （ZA）, T5 （SP ＋ urea）, T6 （SP ＋ ZA）, T7 （RP ＋ urea）, T8 （RP ＋ ZA）. Size of plot was 2 m × 3 m, fertilized with 50 kg N/ha and 200 kg P2O5/ha, according to the assigned treatment. All plot received basal fertilizer of KCI （100 kg KzO/ha） and goat manure （5 ton/ha）. Calopogonium mucunoides was defoliated and nutritive value. Result showed that dry matter production on 90 days after planting and analyzed for dry matter production and nutritive value significantly influenzed by the treatments. Combination between N （ZA, urea） and P （SP, RP） fertilizer resulted dry matter production, nutrient uptake, and dry matter digestibility significantly higher compared to control, and NP fertilization separatedly. Combination of RP and N （urea, ZA） resulted in dry matter production, nutrient uptake, and dry matter digestibility non-significantly different compared to SP in combination with N （urea, ZA）. Therefore, RP could replace SP if combined with urea or ZA to increase production and nutritive value of Calopogonium mucunoides in acid latosolic soil.
文摘Microalgae lipids/oils are a promising feedstock for biodiesel production. The desired lipids are triacylglycerols. These can either be transesterified to biodiesel or decarboxylated to ＂green diesel＂. Increasing microalgae lipids production by thermal stressing is important in improving the economics of biodiesel production, but its effectiveness needs to be determined. This paper focuses on the effect of cooling stressing lipid triggering on the microalgae production and lipids yield. Two microalgae species were studied, Chlorella sp. and Dunaliella. In each case, microalgae were grown in two identical 2 L PBRs （photobiorectors） at room temperature. At the end of the exponential growth phase, one PBR was placed in a cold environment while the other PBR was left at room temperature. Microalgae was harvested, freeze dried and the algae oil was extracted. Measurements show that cooling stressing slightly increased the biomass of algae （11% for C2 and 13% for Dunaliella）, but it decreased the lipids content of the microalgae, 62% for Chlorella sp. and 13% for Dunaliella. The net effect is a decrease in the lipid production rate （mg lipid/L-day） 58% in case of Chlorella sp., and 2% in case of Dunaliella.
文摘Animal nutrition is one of the most important limiting factors in animal production, especially in ruminants, providing proteins being the main constraint, due to the limited availability and high cost of protein sources （oilseed meals）. Currently in the dam ＂El lnfiernillo＂ in Michoacan Mexico, has a large population of devil fish （Pterygoplichthys spp.）, which is an economic and ecological problem, because it is not consumed by humans and causes pollution to be discarded directly into the environment. For that reason the objective of this study was to evaluate the use of silage acid devil fish （SADF） in fattening beef cattle as a protein supplement. SADF is defined as a product semi-liquid or pasty mixed with formic acid, which leads to a decrease in pH to near 4.0. Used 18 young bulls （Bos taurus × Bos indicus） for 60 days with a starting weight of 278.9 ± 51.2 kg, housed in individual pens with food and water ad libitum were randomly assigned to three treatments with different levels of inclusion SADF （0%, 12% and 18%）. They were weighed to the beginning of the experiment and later every 30 days, previous fasting of 24 hours. To determine the food consumption, weigh every day the offered food and the surplus. There were no significant differences （P 〈 0.05） among treatments with different levels of inclusion of SADF with respect to daily weight gain, with values of 952 ± 324, 927 ±322 and 854 ± 307 g/day, respectively. The dry matter intake （DMI） was 8.9, 9.3 and 7.7 kg/day to 0%, 12% and 18% of SADF, respectively. In the same values for feed conversion were 9.34, 10.03 and 9.01 kg DMI/kg of weigh live, and carcass yield of 60.6%, 60.3% and 58.5%, respectively. It is concluded that fish silage acid devil is an excellent alternative in feeding beef cattle as a protein supplement.
