Early tertiary age of pitchstone in the northern black hills, South dakota

A block of pitchstone in the northern Black Hills, South Dakota, is Paleocene in age, according to potassium-argon dating of biotite and fission-track dating of zircon in the sample. These data invalidate published suggestions that the age is much younger. The pitchstone is not extrusive in its present position but instead is in a volcanic pipe with other fragments that came downward from as much as 1100 meters above the modern surface.     

Equatorius: a new hominoid genus from the Middle Miocene of Kenya

A partial hominoid skeleton just older than 15 million years from sediments in the Tugen Hills of north central Kenya mandates a revision of the hominoid genus Kenyapithecus, a possible early member of the great ape-human clade. The Tugen Hills specimen represents a new genus, which also incorporates all material previously referable to Kenyapithecus africanus. The new taxon is derived with respect to earlier Miocene hominoids but is primitive with respect to the younger species Kenyapithecus wickeri and therefore is a late member of the stem hominoid radiation in the East African Miocene.     

Terrestrial ages of four allan hills meteorites: consequences for antarctic ice

The terrestrial ages of three Allan Hills meteorites are between 3 x 10(4) and 3 x 10(5) years and one is (1.54(-0.28)(+0.14)) x 10(6) years old. The Antarctic ice sheet is therefore older than (1.54(-0.28)(+0.14)) x 10(6) years and the meteorite accumulation process at Allan Hills probably began between 3 x 10(4) and 3 x 10(5)years ago.     

Catch a falling star: meteorites and old ice

A model for the process of meteorite concentration in blue ice regions of the Antarctic ice sheet is proposed based on data from near the Allan Hills and the assumptions that both meteorite influx and glacial flow have been constant. The meteorite influx is calculated to be 60 x 10(-6) kilogram per square kilometer per year, and the age of the exposed ice to be 0 to 600,000 years, varying with distance from the Allan Hills. These results are in line with other estimates of influx rate and with measurements of the terrestrial ages of the meteorites, providing support for the assumption of steady flow and meteorite influx. This may be the oldest sequence of ice in stratigraphic order yet discovered, and the results imply that this part of the east Antarctic ice sheet has been approximately steady during this time interval.     

红花玉兰潜在引种气候适生区研究

红花玉兰Magnolia wufengensis是近年在湖北五峰发现的木兰科Magnoliaceae木兰属Magnolia植物新种,其树形高大,花被片内外纯红,具有极高的观赏价值,可作为城市绿化树种和山地景观树种。为科学合理开展红花玉兰引种,避免盲目和失败,需要对红花玉兰在中国的可能引种区域进行划分。根据植物引种气候相似性原理,选取年平均气温、最热月平均气温、最冷月平均气温、年极端最高气温、年极端最低气温、年平均降水量、年平均风速、年平均相对湿度、年日照时数等9个气候因子,采用模糊数学中的欧氏距离模糊相似优先比法,并结合层次分析法对红花玉兰进行气候适生区划分,确定了红花玉兰引种的适宜区、次适宜区和不适宜区。红花玉兰引种适宜区包括黄淮平原、长江中下游平原、江南丘陵、浙闽丘陵、四川盆地东南部、云贵高原东北部和两广丘陵北部地区。该区受亚热带季风影响,雨热同期,容易形成内涝和病虫害,因此,引种红花玉兰在夏季要及时做好圃地清理、病虫害防治及排水工作;红花玉兰引种次适宜区包括四川盆地西北部、云贵高原西南部、两广丘陵南部、雷州半岛、海南岛和台湾岛、晋冀鲁山地丘陵地带、华北平原、辽东半岛、黄土高原中部及青藏高原东南部地区。该区部分地区持续低温时间较长且极端气温较低,栽植苗龄为3~4年生及以下的红花玉兰易受冻害,应进行越冬防寒;红花玉兰引种不适宜区为东北平原、黄土高原西北部、青藏高原西北部、新疆、内蒙古等地。表 10参33     

海南黑牛体型外貌测定与杂交效果初探

海南黑牛是利用良种日本黑毛和牛的冷冻精液与海南黄牛(雷琼黄牛)母牛进行人工授精所产的杂交后代.通过对海南黑牛进行外貌观察和体尺测量,研究其体型外貌与双亲的差异.结果表明,海南黑牛的多项体尺指标与母、父本相比都发生了变化.其外貌主要特征表现为头小颈短、面部清秀,体躯紧凑,背腰平直,无肩峰,毛呈黑色;而体尺测量除管围和管围指数外,体重、体高、胸围、体长等指标均比海南黄牛要小.即在外貌特征上,海南黑牛总体表现双亲的特性,毛色呈现日本和牛黑毛,体型接近海南黄牛小而清秀,但前期生长发育缓慢,表现出当地小型黄牛的特性.     

Fantasy and reality: The black farmer's place in American agriculture

The shared hopes of farm ownership in America motivated many Black farmers and educators during the nineteenth and early twentieth centuries. Although an independent Black yeomanry was not to be, and a host of factors have combined to remove Black Americans from farming, the quest has not been a vain one. Black land-grant institutions continue to redefine their mission in a changing world and in the process maintain their relevancy.     

关于黑土分类和分布问题的探讨

黑土的分布面积在文献中有不同的记载,这主要是由于不同的分类体系产生的,论述了在国内有影响的五个土壤分类体系对黑土的界定,并说明不同分类体系黑土的面积。     

瘦肉型杂交猪肥育、屠宰效果的研究

本研究是《推广瘦肉型杂交猪》重点科技承包项目的重点配套研究课题。1987—1989年分别对杜×甘白、杜×甘黑、汉×甘白、汉×甘黑、长×甘白、长×甘黑、大约×甘白(杜:杜洛克猪;汉:汉普夏猪;长:长白猪;大约:大约克夏猪;甘黑:甘肃黑猪;甘白:甘肃白猪。)的七个杂交组合和甘白×甘白、甘黑×甘黑、甘白×甘黑三个母本专试组进行了测定。育肥试猪共178头,屠宰试猪共114头。结果表明,杂交组合的肥育和屠宰各项指标均高于母本纯繁对照,日增重高55.18克相似文献   

The African American experience in agriculture

Shrinking enrollments in the agricultural programs of the 1890 schools can be partly explained by negative attitudes of Blacks toward agriculture. This attitude has roots in the historical experiences of African Americans and has negative implications for the agricultural programs of the 1890 schools. A collection of data from a sample of Black Louisiana Farmers lends credence to the claim that Black Farmers are not encouraging their children to go into farming. To counter the impact on the 1890 schools, an active recruiting program should be undertaken, partly to show Black students that career openings in various agricultural fields offer excellent opportunities for Black students. These fields extend beyond the traditional farmgate.     

Speciation of Black-necked Crane

1　Introduction　　 The latest crane species to be discribed was the Black- necked Crane (Grus nigricollis) ofthe Qinghai- Tibetan Plateau.It was first located in1 876 at Qinghai Lake,China,since thenChinese scientists have conducted extensive research on this species,especially on its popula-tion status and distribution(Yao and L iao1 984) ,population structure(L i and Zhou1 987) ,wintering ecology(L u1 983,Wu1 985) ,and breeding ecology(Lu and Yao1 980 ,Yao and Liao1 984) .However,li…     

Dynamics of liquefaction during the 1987 superstition hills, california, earthquake

Simultaneous measurements of seismically induced pore-water pressure changes and surface and subsurface accelerations at a site undergoing liquefaction caused by the Superstition Hills, California, earthquake (24 November 1987; M = 6.6) reveal that total pore pressures approached lithostatic conditions, but, unexpectedly, after most of the strong motion ceased. Excess pore pressures were generated once horizontal acceleration exceeded a threshold value.     

和田黑鸡与三黄鸡血浆蛋白及血象指标的比较研究

应用常规的血液学指标测定方法,测定了和田黑鸡与三黄鸡血液学指标。结果表明:和田黑鸡雌雄个体之间血浆总蛋白、血浆白蛋白和血浆球蛋白无显著差异（P>0.05）,其中白蛋白与球蛋白之比小于1。和田黑鸡的血浆总蛋白、血浆白蛋白和血浆球蛋白极显著（P<0.01）高于三黄鸡。和田黑鸡WBC雄性高于雌性,但差异不显著（P>0.05）;而RBC、HGB表现为雌性高于雄性,其中HGB差异不显著（P>0.05）,RBC雌性为(4.52±0.041×10¹²/L,雄性为（3.78±0.12）×10¹²/L,雌性显著高于雄性（0.01相似文献   

黑熊肩胛骨、臂骨解剖特性的观察与比较

以黑熊为研究对象,应用解剖学的方法和理论知识,阐明肩胛骨、臂骨的分辨方法及特殊形态结构,根据测量学的理论基础对黑熊前肢骨的30多项指标、指数进行测量与计算,并与大熊猫进行比较,发现两者形态结构基本相似,但黑熊明显区别于大熊猫之处,就是没有内上髁孔.     

寓动于山，健体于林——谈徐州市凤凰山、泰山山景公园规划

城市公园以其特有的开放性和优良的绿地资源成为市民重要的活动场所;在公园中进行运动健身成为休闲行为主流。以徐州市凤凰山、泰山山景公园规划为例,从现状调研、规划理念、总体布局、林相改造等方面探讨如何营造宜于市民健身休闲活动的城市公园。     

黑熊股骨、胫骨和腓骨解剖特性的观察与比较

对黑熊股骨、胫骨和腓骨的近百项指标进行全面测量,并计算各项指数,再通过查找资料,与人、大熊猫、牛和狗的测量结果进行对比.结果表明,黑熊与大熊猫指数差异较小,人和其他动物与黑熊指数差异较大.     

山东省地方畜禽品种资源的保护与利用研究

山东省地方畜禽品种资源丰富。有地方畜禽品种32个,已对烟台黑猪、莱芜黑猪等5个猪种、鲁西黄牛、德州驴、小尾寒羊、洼地绵羊、黑耳兔等19个畜种资源按照标准进行了主产地、分布区域、群体规模的描述。采集耳组织、血细胞样本800余个,并对这些样本进行了DNA提取和基因组学的分析,初步建立了山东地方家畜遗传资源库。利用地方良种历经10余年已经培育出了鲁烟白猪新品种和鲁农Ⅰ号猪配套系。     

Black sea: recent sedimentary history

Three distinct sedimentary units, which can be correlated throughout the basin, occur in cores collected from the Black Sea. Carbon-14 ages help to define the recent sedimentary history of the Black Sea.     

红花尔基保护区黑琴鸡越冬初期生境选择

为了探讨黑琴鸡越冬初期的生境选择策略,2006—2009年的10月中旬,利用样方法、因子测定法、卡方检验等方法对内蒙古红花尔基樟子松林国家级自然保护区的黑琴鸡越冬初期的生境选择进行了调查分析。研究结果表明:越冬初期,黑琴鸡觅食、栖息的生境具有以下特征:对草地—樟子松林和较开阔的草地选择性较高(75.4%),海拔较低(多为700~800 m),坡度在20°以下的中下坡位,而距离村镇的距离比较远,多在8~12 km,距公路的距离多大于2 km,而距林缘的距离则多选择在40 m以内。     

11个鸭种(群)遗传变异的微卫星标记分析

利用9个微卫星标记对高邮鸭、金定鸭、荆江麻鸭、山麻鸭、白羽番鸭、黑羽番鸭（纯黑）、黑羽番鸭（白头）、苏牧麻鸭、苏牧白羽鸭、苏牧黑鸭及龙白鸭11个鸭种（群）的平均基因杂合度、平均多态信息含量进行了分析。结果表明：11个鸭种（群）在9个微卫星座位上的基因频率存在一定差异．其平均基因杂合度为0．6599.平均多态信息含量为0．5966。其中．黑羽番鸭（白头）平均基因杂合度最高．为0．6948．遗传多样性最丰富;荆江麻鸭平均遗传杂合度最低,为0．5757。