In this study, we examined the varia- tions between the difference method and the enzyme- hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal p...In this study, we examined the varia- tions between the difference method and the enzyme- hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal protein-containing diets. These methods were compared to the nitrogen-free （N-free） diet method. The difference method was based on soy- bean meal as the only protein source, with the experi- mental diets containing crude protein levels at 15% and 20%. The enzyme-hydrolyzed casein method was based on enzyme-hydrolyzed casein meal as the pro- tein source, with the experimental diet containing a crude protein level of 17.5%. The N-free diet was prepared with starches and paper fibers. In each meth- od,64 Tianfu meat drakes （7-weeks-old） with an av- erage body weight of 2.77±0.16 kg were used and divided into four groups, and fed four different diets. Each group contained four replicates of four drakes and they were force fed trial diets according to the Sirbald method for detecting their apparent amino aciddigestibility, endogenous amino acid loss and true a- mino acid digestibility. The results demonstrated that using the difference, enzyme-hydrolyzed casein and N-free diet methods, endogenous amino acid losses were 0. 9946,1. 2243 and 0. 9297 mg/g dry matter in- take （ DMI）, respectively. The true amino acid digest- ibility measured by the difference method was 88.93 %±4.43 %. Using the enzyme-hydrolyzed ca- sein method with two dietary crude protein levels of 15% and 20%, the digestibility was 91.15%±4.33% and 91.97%±4. 16%, respectively, and by the N-free diet methods with two dietary crude protein levels of 15% and 20% ,it was 88.55%±4.29% and 88.82 %±4.61%, respectively. The results suggested that when the dietary protein level was 15% to 20 %, the true amino acid digestibility and endogenous ami- no acid loss as determined by the difference method was more accurate than the values determined by the enzyme-hydrolyzed casein method.展开更多
The Drake formula is a statistical method of forecasting the possible number N of technically evolved extraterrestrial and galactic civilizations able to communicate with the human species. It is based on seven differ...The Drake formula is a statistical method of forecasting the possible number N of technically evolved extraterrestrial and galactic civilizations able to communicate with the human species. It is based on seven different factors that can be grouped into factors of type A, f<sub>A</sub> (“Astrophysicist”) and type B, f<sub>B</sub> (“Astrobiological”). The quantitative analysis of these factors at the time of the presentation of the formula was subjective and highly variable for both factors f<sub>A</sub> and f<sub>B</sub>. Current scientifical and technological development has made it possible to refine the quantitative estimates of the f<sub>A</sub> group whose definition is now less uncertain. In group f<sub>A</sub> the parameter n<sub>e</sub> is understood as the number of planets capable of sustaining life. By means of n<sub>e</sub> Drake defines this possibility exclusively from the geometric point of view. In particular, the planet’s orbit must be included in the circumstellar space in which the planetary temperature allows the presence of liquid water. This is not enough because, for liquid (and gaseous) water to be present on the planet’s surface, it is also essential that the planet has a magnetic field of adequate intensity to shield the flow of charged particles coming from its star (solar wind). The solar wind is able to break up and disperse the liquid and gaseous water molecules and any organic molecules in times much shorter than theoretically necessary for the formation of life and above all, except for singularities, than necessary for evolution to arrive at intelligent life. Here the planetary magnetic field parameter n<sub>m</sub> is introduced into the Drake formula and its statistical probability of existence is discussed.展开更多
The impacts of opening the Drake Passage(DP) on the oceanic general circulation are examined.When the DP is open,wind stress at mid-and high latitudes gives rise to a wind-driven gyre,which induces a meridional heat e...The impacts of opening the Drake Passage(DP) on the oceanic general circulation are examined.When the DP is open,wind stress at mid-and high latitudes gives rise to a wind-driven gyre,which induces a meridional heat exchange between mid-and high latitudes in the Southern Ocean.After the opening of the DP,the Antarctic Circumpolar Current(ACC) forms and its associated strong temperature front blocks the heat transport from mid-latitudes to high latitudes.A simple box model is formulated,in which the effects of the wind stress(for the case of DP closed) and the thermal front(for the case of DP open) on the variability of Antarctic Bottom Water(AABW) and North Atlantic Deep Water(NADW) are explored.The sensitivity experiments demonstrate that:(1) When the DP is closed,the enhancement of the wind-driven gyre leads to the decline of AABW formation in the Southern Ocean and the increase of NADW formation in the North Atlantic.As a result,water in high latitudes of the Southern Ocean becomes warmer,so does the bottom water of global ocean.(2) When the DP is open,there is no formation of AABW until the intensity of thermal front along ACC exceeds a threshold value(it is 4.03℃ in our model).Before the formation of AABW,temperature in most of the oceans is higher than that after the formation of AABW,which usually leads to the cooling of high latitudes of the Southern Hemisphere and the bottom water in global ocean.When the strength of the thermal front is lower than the critical value,there is no AABW formation,and temperature in most of the oceans is slightly higher.These results demonstrate that during the opening of the DP,changes in wind stress and the formation of the thermal front in the Southern Ocean can substantially affect the formation of AABW and NADW,thus changing the state of meridional overturning circulation in the global ocean.展开更多
The Drake Passage is the seaway between South America and Antarctica. It is widely believed that the thermal isolation effects caused by the opening of the Drake Passage played an important role in the abrupt cooling ...The Drake Passage is the seaway between South America and Antarctica. It is widely believed that the thermal isolation effects caused by the opening of the Drake Passage played an important role in the abrupt cooling that occurred at the Eocene-Oligocene boundary in the Cenozoic. These effects are also thought to be independent of the geometry of the passage. Here, the authors demonstrate that the climate impacts of the Drake Passage depend on the passage geometry by comparing the climate's sensitivity to the opening of the Drake Passage under the present and the Early Eocene land-sea configurations. These experiments show that the thermal isolation effects caused by the passage are much stronger under the present land-sea configuration. In comparison, under the Early Eocene land-sea configuration, the weak anomalies in heat transport caused by the opening of the narrow and shallow Drake Passage are not strong enough to thermally insulate Antarctica. The climate effects of the Drake Passage on the Cenozoic cooling have been overestimated in previous sensitivity studies carried out using the present land-sea configuration. Thus, it is unlikely that the opening of the Drake Passage played an essential role in the abrupt Cenozoic cooling, especially in the abrupt cooling at the Eocene-Oligocene boundary.展开更多
嘻哈已死?不不不,是Auto Tune已死,嘻哈复兴,而且它在变得更加具有生命力。嘻哈与电子,摇滚,流行甚至民谣等曲风的跨界合作以及融合,边说边唱的讨好曲风,新生代逐渐接过老炮的枪,这些发展趋势让2010年无疑成为嘻哈音乐复兴的大年,也使...嘻哈已死?不不不,是Auto Tune已死,嘻哈复兴,而且它在变得更加具有生命力。嘻哈与电子,摇滚,流行甚至民谣等曲风的跨界合作以及融合,边说边唱的讨好曲风,新生代逐渐接过老炮的枪,这些发展趋势让2010年无疑成为嘻哈音乐复兴的大年,也使得嘻哈音乐占据了53届格莱美的半壁江山。Eminem凭借《Recovery》重新复苏,勇夺10项格莱美提名领跑众将;Jay-Z也不甘示弱凭借与Alicia Keys合唱的《Empire State of Mind》通知各项单曲奖提名。展开更多
项目地址美国曼哈顿设计单位Drake Desion AssociatesOne57是美国Extell地产开发公司在近期推出的90层公寓楼项目,大楼由获得了普利兹克建筑大奖的法国著名建筑师Christian de Portzamparc设计,楼高1004英尺,毗邻卡内基音乐厅,是美国排...项目地址美国曼哈顿设计单位Drake Desion AssociatesOne57是美国Extell地产开发公司在近期推出的90层公寓楼项目,大楼由获得了普利兹克建筑大奖的法国著名建筑师Christian de Portzamparc设计,楼高1004英尺,毗邻卡内基音乐厅,是美国排名第十四高的建筑,同时也是纽约的最高公寓楼。近日,纽约顶尖设计大师Jamie Drake完成了One57第58层的一间公寓的室内设计。开发商希望公寓采用素净大方的风格,以吸引一群潜在客户。同时,他们也提出设计师可以大胆用色,但要避免因太多且杂的色彩而影响空间调性。展开更多
Identifying home ranges—those areas traversed by individuals in their normal foraging,mating,and parenting activities—is an important aspect of cetacean study.Understanding these ranges facilitates identification of...Identifying home ranges—those areas traversed by individuals in their normal foraging,mating,and parenting activities—is an important aspect of cetacean study.Understanding these ranges facilitates identification of resource use and conservation.Fin and humpback whales occur in Antarctica during the austral summer,but information regarding their home ranges is limited.Using opportunistically collected whale sighting data from eight consecutive summer seasons spanning 2010–2017,we approximate the home ranges of humpback and fin whales around Drake Passage(DRA),West of Antarctic Peninsula(WAP),South Shetland Islands(SSI),an area northwest of the Weddell Sea(WED),and around the South Orkney Islands(SOI).Approximate home ranges are identified using Kernel Density Estimation(KDE).Most fin whales occurred north and northwest of the SOI,which suggests that waters near these islands support concentrations of this species.Most humpback whales were observed around the SSI,but unlike fin whales,their distributions were highly variable in other areas.KDE suggests spatial segregation in areas where both species exist such as SOI,SSI,and WPA.Partial redundancy analysis(pRDA)suggests that the distributions of these species are more affected by spatial variables(latitude,longitude)than by local scale variables such as sea surface temperature and depth.This study presents a visual approximation of the home ranges of fin and humpback whales,and identifies variation in the effects of space and environmental variables on the distributions of these whales at different spatial scales.展开更多
文摘In this study, we examined the varia- tions between the difference method and the enzyme- hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal protein-containing diets. These methods were compared to the nitrogen-free （N-free） diet method. The difference method was based on soy- bean meal as the only protein source, with the experi- mental diets containing crude protein levels at 15% and 20%. The enzyme-hydrolyzed casein method was based on enzyme-hydrolyzed casein meal as the pro- tein source, with the experimental diet containing a crude protein level of 17.5%. The N-free diet was prepared with starches and paper fibers. In each meth- od,64 Tianfu meat drakes （7-weeks-old） with an av- erage body weight of 2.77±0.16 kg were used and divided into four groups, and fed four different diets. Each group contained four replicates of four drakes and they were force fed trial diets according to the Sirbald method for detecting their apparent amino aciddigestibility, endogenous amino acid loss and true a- mino acid digestibility. The results demonstrated that using the difference, enzyme-hydrolyzed casein and N-free diet methods, endogenous amino acid losses were 0. 9946,1. 2243 and 0. 9297 mg/g dry matter in- take （ DMI）, respectively. The true amino acid digest- ibility measured by the difference method was 88.93 %±4.43 %. Using the enzyme-hydrolyzed ca- sein method with two dietary crude protein levels of 15% and 20%, the digestibility was 91.15%±4.33% and 91.97%±4. 16%, respectively, and by the N-free diet methods with two dietary crude protein levels of 15% and 20% ,it was 88.55%±4.29% and 88.82 %±4.61%, respectively. The results suggested that when the dietary protein level was 15% to 20 %, the true amino acid digestibility and endogenous ami- no acid loss as determined by the difference method was more accurate than the values determined by the enzyme-hydrolyzed casein method.
文摘The Drake formula is a statistical method of forecasting the possible number N of technically evolved extraterrestrial and galactic civilizations able to communicate with the human species. It is based on seven different factors that can be grouped into factors of type A, f<sub>A</sub> (“Astrophysicist”) and type B, f<sub>B</sub> (“Astrobiological”). The quantitative analysis of these factors at the time of the presentation of the formula was subjective and highly variable for both factors f<sub>A</sub> and f<sub>B</sub>. Current scientifical and technological development has made it possible to refine the quantitative estimates of the f<sub>A</sub> group whose definition is now less uncertain. In group f<sub>A</sub> the parameter n<sub>e</sub> is understood as the number of planets capable of sustaining life. By means of n<sub>e</sub> Drake defines this possibility exclusively from the geometric point of view. In particular, the planet’s orbit must be included in the circumstellar space in which the planetary temperature allows the presence of liquid water. This is not enough because, for liquid (and gaseous) water to be present on the planet’s surface, it is also essential that the planet has a magnetic field of adequate intensity to shield the flow of charged particles coming from its star (solar wind). The solar wind is able to break up and disperse the liquid and gaseous water molecules and any organic molecules in times much shorter than theoretically necessary for the formation of life and above all, except for singularities, than necessary for evolution to arrive at intelligent life. Here the planetary magnetic field parameter n<sub>m</sub> is introduced into the Drake formula and its statistical probability of existence is discussed.
基金supported by National Basic Research Program of China(Grant No.2012CB957802)the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes(Grant No.CHINARE2012-04-04)+1 种基金Program of International Science and Technology Cooperation(Grant No.S2011GR0348)National Natural Science Foundation of China(Grant No.41176029)
文摘The impacts of opening the Drake Passage(DP) on the oceanic general circulation are examined.When the DP is open,wind stress at mid-and high latitudes gives rise to a wind-driven gyre,which induces a meridional heat exchange between mid-and high latitudes in the Southern Ocean.After the opening of the DP,the Antarctic Circumpolar Current(ACC) forms and its associated strong temperature front blocks the heat transport from mid-latitudes to high latitudes.A simple box model is formulated,in which the effects of the wind stress(for the case of DP closed) and the thermal front(for the case of DP open) on the variability of Antarctic Bottom Water(AABW) and North Atlantic Deep Water(NADW) are explored.The sensitivity experiments demonstrate that:(1) When the DP is closed,the enhancement of the wind-driven gyre leads to the decline of AABW formation in the Southern Ocean and the increase of NADW formation in the North Atlantic.As a result,water in high latitudes of the Southern Ocean becomes warmer,so does the bottom water of global ocean.(2) When the DP is open,there is no formation of AABW until the intensity of thermal front along ACC exceeds a threshold value(it is 4.03℃ in our model).Before the formation of AABW,temperature in most of the oceans is higher than that after the formation of AABW,which usually leads to the cooling of high latitudes of the Southern Hemisphere and the bottom water in global ocean.When the strength of the thermal front is lower than the critical value,there is no AABW formation,and temperature in most of the oceans is slightly higher.These results demonstrate that during the opening of the DP,changes in wind stress and the formation of the thermal front in the Southern Ocean can substantially affect the formation of AABW and NADW,thus changing the state of meridional overturning circulation in the global ocean.
基金supported by the National Natural Science Foundation of China under Grant 40902054the Earth System Model Modeling project supported by Statoil, Norway
文摘The Drake Passage is the seaway between South America and Antarctica. It is widely believed that the thermal isolation effects caused by the opening of the Drake Passage played an important role in the abrupt cooling that occurred at the Eocene-Oligocene boundary in the Cenozoic. These effects are also thought to be independent of the geometry of the passage. Here, the authors demonstrate that the climate impacts of the Drake Passage depend on the passage geometry by comparing the climate's sensitivity to the opening of the Drake Passage under the present and the Early Eocene land-sea configurations. These experiments show that the thermal isolation effects caused by the passage are much stronger under the present land-sea configuration. In comparison, under the Early Eocene land-sea configuration, the weak anomalies in heat transport caused by the opening of the narrow and shallow Drake Passage are not strong enough to thermally insulate Antarctica. The climate effects of the Drake Passage on the Cenozoic cooling have been overestimated in previous sensitivity studies carried out using the present land-sea configuration. Thus, it is unlikely that the opening of the Drake Passage played an essential role in the abrupt Cenozoic cooling, especially in the abrupt cooling at the Eocene-Oligocene boundary.
文摘嘻哈已死?不不不,是Auto Tune已死,嘻哈复兴,而且它在变得更加具有生命力。嘻哈与电子,摇滚,流行甚至民谣等曲风的跨界合作以及融合,边说边唱的讨好曲风,新生代逐渐接过老炮的枪,这些发展趋势让2010年无疑成为嘻哈音乐复兴的大年,也使得嘻哈音乐占据了53届格莱美的半壁江山。Eminem凭借《Recovery》重新复苏,勇夺10项格莱美提名领跑众将;Jay-Z也不甘示弱凭借与Alicia Keys合唱的《Empire State of Mind》通知各项单曲奖提名。
基金This work was conducted with logistical and financial support of the Instituto Antártico Argentino.
文摘Identifying home ranges—those areas traversed by individuals in their normal foraging,mating,and parenting activities—is an important aspect of cetacean study.Understanding these ranges facilitates identification of resource use and conservation.Fin and humpback whales occur in Antarctica during the austral summer,but information regarding their home ranges is limited.Using opportunistically collected whale sighting data from eight consecutive summer seasons spanning 2010–2017,we approximate the home ranges of humpback and fin whales around Drake Passage(DRA),West of Antarctic Peninsula(WAP),South Shetland Islands(SSI),an area northwest of the Weddell Sea(WED),and around the South Orkney Islands(SOI).Approximate home ranges are identified using Kernel Density Estimation(KDE).Most fin whales occurred north and northwest of the SOI,which suggests that waters near these islands support concentrations of this species.Most humpback whales were observed around the SSI,but unlike fin whales,their distributions were highly variable in other areas.KDE suggests spatial segregation in areas where both species exist such as SOI,SSI,and WPA.Partial redundancy analysis(pRDA)suggests that the distributions of these species are more affected by spatial variables(latitude,longitude)than by local scale variables such as sea surface temperature and depth.This study presents a visual approximation of the home ranges of fin and humpback whales,and identifies variation in the effects of space and environmental variables on the distributions of these whales at different spatial scales.
