Species duration and evolution: benthic foraminifera on the atlantic continental margin of north america

Average species durations were estimated for 131 commonly occurring modern species. The duration of species occurring at depths of less than 200 meters is 16 million years, while for those at greater than 200 meters and at all depths it is 25 to 26 million years. Species (less than 200 meters) distributed from Florida to Newfoundland and from Florida to Cape Hatteras have about the same durations (18 to 20 million years). The duration for species restricted to north of Cape Hatteras is only 7 million years. The data suggest that evolutionary rates are greater in shallower than in deeper depths and greatest in the shallower northern area.     

Venus: a contrast in evolution to Earth

Of the planets, Venus and Earth are by far the most similar in primary properties, yet they differ markedly in secondary properties. A great impact into Earth is believed to have created its moon and removed its atmosphere; the lack of such an impact into Venus apparently led to a greatly differing atmospheric evolution. The lack of an ocean on Venus prevents the recycling of volatiles and inhibits subduction, so that its crust is probably more voluminous than Earth's, although distorted and quite variable in thickness. Venus's upper mantle appears to be depleted in both volatiles and energy sources because, in addition to the lack of volatile recycling, melts of mantle rocks are more dense than their solid matrix at pressures above 8 gigapascals and hence sink if they occur at depths below 250 kilometers. Appreciable energy sources persist at great depths to sustain the few great mountain complexes. The greatest current problem is reconciling the likelihood of a voluminous crust with indications of considerable strength at shallow depths of 20 to 100 kilometers.     

Splashing of drops on shallow liquids

The events that follow the splashing of a drop on a liquid depend on the depth of the liquid. When the depth is less than about 5 millimeters the crown that is ejected is more unstable than that from a splash on a deep liquid. As the depth is decreased from 25 to 7 millimeters, there is an increase in the maximum height to which the Rayleigh jet rises, and in the number of drops that break away from the jet. With depths less than 7 millimeters these two quantities fall off sharply, and no jet drops are produced for depths less than about 3 millimeters.     

Radiolarian skeletons: solution at depths

Radiolarian skeletons were placed at several depths on the taut mooring wire of a buoy in the central Pacific for 4 months. Recent radiolarian sediment dissolved at appreciable rates at depths shallower than 2000 meters; solution was greatest near the surface and decreased with depth. This pattern correlates with bathymetric distributions of dissolved silicon and of temperature. Siliceous Radiolaria from planktonic samples appeared to dissolve about eight times faster than those from sediment. Tripyleans seemed to be less resistant than polycystins. Acantharia dissolved completely at all depths.     

沙埋和种子大小对沙蒿种子萌发及幼苗生长的影响

研究实验室条件下不同深度的沙埋和种子大小对沙蒿种子萌发及幼苗生长的影响。结果表明,沙埋深度对沙蒿的种子萌发率、休眠率、幼苗出土率及生物量均有显著影响。没有沙土覆盖时沙蒿种子即可萌发;0.5~5 cm的浅层沙埋下,种子萌发率、出苗率、幼苗存活率及生物量最高,休眠率最低;沙埋深度>5 cm 时,沙蒿的种子萌发率、出苗率、幼苗存活率及生物量随沙埋深度增加显著降低,而休眠率却显著升高;沙埋深度为12 cm时,种子不出苗,幼苗也不能存活。种子大小对沙蒿种子萌发率、出苗率、幼苗存活率及休眠率均无显著影响,但对幼苗生物量大小具有显著影响,在0~12 cm的沙埋深度中,除5 cm和7 cm深度下中粒种子和小粒种子萌发的幼苗的生物量间没有显著差异外,其他深度处理时,大粒种子萌发的幼苗的生物量显著高于同一沙埋深度下中粒种子萌发的幼苗生物量,后者又显著高于小粒种子萌发幼苗的生物量,因此研究认为,沙蒿种子最适宜沙埋深度为 1~ 3 cm的浅层沙埋。     

Ultradeep (greater than 300 kilometers), ultramafic upper mantle xenoliths

Geophysical discontinuities in Earth's upper mantle and experimental data predict the structural transformation of pyroxene to garnet and the solid-state dissolution of pyroxene into garnet with increasing depth. These predictions are indirectly verified by omphacitic pyroxene exsolution in pyropic garnet-bearing xenoliths from a diamondiferous kimberlite. Conditions for silicon in octahedral sites in the original garnets are met at pressures greater than 130 kilobars, placing the origin of these xenoliths at depths of 300 to 400 kilometers. These ultradeep xenoliths support the theory that the 400-km seismic discontinuity is marked by a transition from peridotite to eclogite.     

Lithologic Control of the Depth of Earthquakes in Southern California

The depth distribution of southern California earthquakes indicates that areas underlain by schist basement rocks have a shallower (4 to 10 kilometers) maximum depth of earthquakes than do areas with other types of basement rocks. The predominant minerals in the schists become plastic at lower temperatures, and thus at shallower depths, than the minerals in the other basement rocks. The lateral variations in lithology will control the depth extent (and thus the magnitudes) of potential future earthquakes; these depths can be determined from the depth of the current background seismicity.     

Irradiation history of Itokawa regolith material deduced from noble gases in the Hayabusa samples

Noble gas isotopes were measured in three rocky grains from asteroid Itokawa to elucidate a history of irradiation from cosmic rays and solar wind on its surface. Large amounts of solar helium (He), neon (Ne), and argon (Ar) trapped in various depths in the grains were observed, which can be explained by multiple implantations of solar wind particles into the grains, combined with preferential He loss caused by frictional wear of space-weathered rims on the grains. Short residence time of less than 8 million years was implied for the grains by an estimate on cosmic-ray-produced (21)Ne. Our results suggest that Itokawa is continuously losing its surface materials into space at a rate of tens of centimeters per million years. The lifetime of Itokawa should be much shorter than the age of our solar system.     

关中地区不同耕作方式对冬小麦产量及土壤蓄水保水能力影响

2020-2021年在陕西省泾阳县设置3个深松深度和2个深翻深度,研究了不同深度的机械深松、深翻对土壤蓄水保水能力及产量影响。结果表明：深松和深翻处理在一定程度上有利于提高深层土壤的蓄水保水能力,播前深翻30 cm和深松30 cm处理80～200 cm各深度平均土壤含水率较对照分别高1.27%和1.64%,冬前、返青期和收获期3个深松深度和2个深翻深度处理80～200 cm各深度平均土壤含水率较对照提高0.13%～3.98%。在深松3个处理中30 cm深度处理产量最高为8 257.5 kg/hm²,较CK增产6.0%,处理之间差异极显著;在深翻2个处理中25 cm深度处理产量最高为8 017.5 kg/hm²,较CK增产3.0%,处理之间差异显著。深松和深翻处理对冬小麦产量的影响与处理深度密切相关,深松以30 cm深度处理,深翻以25 cm深度处理为最佳。     

丹参地下害虫种类与垂直分布的初步研究

[目的]为了提高丹参的产量与质量。[方法]对陕西商洛地区丹参地下害虫进行初步研究。[结果]结果表明:丹参地下害虫种类有11种,隶属于3目6科;蛴螬在地面到地下60 cm的垂直分布存在一定差异,其中在地下20~40 cm区域的分布明显多于其他区域;金针虫在地面到地下60 cm的垂直分布差异不显著。[结论]该研究为防治丹参地下害虫提供了理论基础,并可促进丹参栽培的可持续发展。     

设施鱼塘冬春季水温日变化特点及其与外界气温的统计模式

为了开展设施鱼塘水温的气象预报和预警,对2007年12月6日至2008年5月20日设施大棚鱼塘水温与气象站气温同步观测资料进行数理统计分析,结果表明：冬、春季大棚不同深度的水温均比气温高6．1～8．3℃;多云及晴天较阴雨天明显偏高。不同深度最低水温除春季多云和晴天比气象站最低气温出现时间早0～1h外,其他时间均晚1～2h。水温日较差与气温类似,为晴天〉多云〉阴天〉雨天,但水温日变化幅度较气温缓和。水温垂直变化不明显,不同深度水温与气温均存在显著的相关性。     

Kinetics of conversion of air bubbles to air hydrate crystals in antarctic ice

The depth dependence of bubble concentration at pressures above the transition to the air hydrate phase and the optical scattering length due to bubbles in deep ice at the South Pole are modeled with diffusion-growth data from the laboratory, taking into account the dependence of age and temperature on depth in the ice. The model fits the available data on bubbles in cores from Vostok and Byrd and on scattering length in deep ice at the South Pole. It explains why bubbles and air hydrate crystals coexist in deep ice over a range of depths as great as 800 meters and predicts that at depths below approximately 1400 meters the AMANDA neutrino observatory at the South Pole will operate unimpaired by light scattering from bubbles.     

复方白头翁胶囊对腹泻犬小肠绒毛长度和隐窝深度的影响

探明复方白头翁胶囊（白头翁、秦皮、三七等）对腹泻犬小肠绒毛高度、隐窝深度和绒毛高度与隐窝深度比值（V/C）的影响,为进一步研究中药复方制剂治疗腹泻的机制提供形态学依据。选用体重（3.0±0.5）kg左右的健康幼犬30只,随机分为3个组：A组（阴性对照组）,B组（阳性对照组,大肠杆菌攻毒）,C组（中药治疗组,大肠杆菌攻毒＋白头翁胶囊治疗）,每组10只。实验期为3 d,第四天取小肠各段组织,并制作石蜡切片。测量肠绒毛高度、隐窝深度和V/C值,用组织学方法研究肠绒毛形态极其变化。结果表明：（1）中药治疗组小肠各段绒毛高度均显著高于阳性对照组（P〈0.05）,小于阴性对照组（P〉0.05）;（2）中药治疗组各段肠隐窝深度均小于阳性对照组（P〉0.05）,大于阴性对照组（P〉0.05）;（3）各组V/C值大小依次为阴性对照组,中药治疗组和阳性对照组,且各组间差异显著（P〈0.05）。结果提示,复方白头翁胶囊对大肠杆菌性腹泻具有的治疗作用与保护肠绒毛和促进肠上皮细胞生长有关。     

Soil temperature estimation at different depths,using remotely-sensed data

Soil temperatures at different depths down the soil profile are important agro-meteorological indicators which are necessary for ecological modeling and precision agricultural activities. In this paper, using time series of soil temperature(ST) measured at different depths(0, 5, 10, 20, and 40 cm) at agro-meteorological stations in northern China as reference data, ST was estimated from land surface temperature(LST) and normalized difference vegetation index(NDVI) derived from AQUA/TERRA MODIS data, and solar declination(Ds) in univariate and multivariate linear regression models. Results showed that when daytime LST is used as predictor, the coefficient of determination(R~2) values decrease from the 0 cm layer to the 40 cm layer. Additionally, with the use of nighttime LST as predictor, the R~2 values were relatively higher at 5, 10 and 15 cm depths than those at 0, 20 and 40 cm depths. It is further observed that the multiple linear regression models for soil temperature estimation outperform the univariate linear regression models based on the root mean squared errors(RMSEs) and R~2. These results have demonstrated the potential of MODIS data in tandem with the Ds parameter for soil temperature estimation at the upper layers of the soil profile where plant roots grow in. To the best of our knowledge, this is the first attempt at the synergistic use of LST, NDVI and Ds for soil temperature estimation at different depths of the upper layers of the soil profile, representing a significant contribution to soil remote sensing.     

Surveyor v: television pictures

Surveyor V landed in a small crater, 8.5 meters wide and 12.5 meters long, which was probably formed by drainage of surficial fragmental debris into a subsurface fissure. The lunar surface debris layer is exposed in the walls of this crater. At depths below about 10 centimeters, the debris appears to be composed mainly of shock-compressed aggregates, ranging from a few millimeters up to 3 centimeters in diameter, set in a matrix of less-coherent finer particles. Rocky chips and fragments larger than a millimeter are dispersed as a subordinate constituent of the debris.     

Seismic evidence for deep-water transportation in the mantle

We report seismic evidence for the transportation of water into the deep mantle in the subduction zone beneath northeastern Japan. Our data indicate that water is released from the hydrated oceanic crust at shallow depths (< approximately 100 kilometers) and then forms a channel of hydrated mantle material on top of the subducting plate that is the pathway for water into the deep mantle. Our result provides direct evidence that shows how water is transported from the ocean to the deep mantle in a cold subduction zone environment.     

The temporal distribution of seismic radiation during deep earthquake rupture

The time history of energy release during earthquakes illuminates the process of failure, which remains enigmatic for events deeper than about 100 kilometers. Stacks of teleseismic records from regional arrays for 122 intermediate (depths of 100 to 350 kilometers) and deep (depths of 350 to 700 kilometers) earthquakes show that the temporal pattern of short-period seismic radiation has a systematic variation with depth. On average, for intermediate depth events more radiation is released toward the beginning of the rupture than near the end, whereas for deep events radiation is released symmetrically over the duration of the event, with an abrupt beginning and end of rupture. These findings suggest a variation in the style of rupture related to decreasing fault heterogeneity with depth.     

免耕条件下不同秸秆覆盖量的土壤有机碳红外光谱特征

【目的】研究不同秸秆覆盖量免耕条件下不同剖面深度土壤的红外光谱特征,探讨免耕对土壤有机碳组成的影响及秸秆来源土壤有机碳在不同土层的分布特征。【方法】以吉林省梨树县黑土秸秆覆盖免耕长期定位试验区不同层次土壤为研究对象,对比分析无秸秆覆盖（CK）、33%秸秆覆盖、67%秸秆覆盖、100%秸秆覆盖4种处理土壤红外光谱特征。【结果】连续5年秸秆覆盖免耕种植后的土壤,红外光谱吸光值随着剖面层次的加深而降低;差减土壤矿物光谱后的谱图表明：0—5 cm土层土壤红外基团吸收明显增加,芳香碳、脂肪碳、烷基碳较之下层土壤具有明显的吸收峰。【结论】秸秆覆盖有利于有机碳在表层的累积,显著增加秸秆来源的芳香碳、脂肪碳及烷基碳含量。     

科尔沁沙地杨树深栽技术初报

通过对钻孔深栽技术和普通造林技术比较研究表明，成活率二者无显著差异，但在高径生长量上差异较大。进一步研究表明，钻孔深栽是科尔沁沙地适宜的造林技术，特别是地下水位较低地类。研究了０．７－３．０ｍ７个深度的成活率和高径生长量表明，１．３ｍ－３．０ｍ５个深度之间成活率、高径生长量无显著差异，０．７ｍ－１．３ｍ之间差异显著（α＜０．０５）。１．３深度造林成活率已达９８％，因此１．３ｍ深度应是生产实践中推广使用深度。对３×３ｍ、４×４ｍ、５×５ｍ、６×６ｍ和６×９ｍ５个密度的６年高径生长量和第１０年蓄积量预测研究表明，５×５ｍ密度的蓄积量均大于其它密度，进而指出，科尔沁沙地适合的深栽造林密度为５×５ｍ。本文对深栽利用的苗木贮藏方式和造林时间进行分析研究得出，造林时间春秋两季皆宜，秋季造林宜早，春季造林可早可晚；春季造林苗木必须冬贮（平放、埋深１ｍ）。     

Seasonality and interaction of biogenic and lithogenic particulate flux at the panama basin

Time-series sediment traps were deployed for an entire year at three depths (890, 2590, and 3560 meters) at a deepwater station (3860 meters) in the Panama Basin. The amount of horizontal and lithogenic particulate material arriving at the three depths was seasonally pulsed and directly reflected changes in surface primary production. Two spikes of organic flux were simultaneously recorded at all three depths: (i) a period of high productivity during regional upwelling in February through March and (ii) an unusual bloom of a single species of coccolithophorid during June through July. This latter spike delivered approximately 25 grams of coccolith per square meter of area at a depth of 3860 meters during less than 60 days. The flux of lithogenic particles increased with increasing depth and was seasonally correlated to surface production and current direction, and not to the detritus discharged in river flow. The data suggest that suspended clays are efficiently scavenged from the water column by rapidly sinking organic aggregates.