Sequential Basal faults in devonian dolomite, nopah range, death valley area, california

Dolomite crystals from the Lost Burro Formation (Devonian) in the Nopah Range, eastern California, display basal stacking disorder as evidenced by transmission electron microscopy. Satellites in electron diffraction patterns indicate that stacking of anions and cations is different from that in ideal dolomite. This example conforms to the model of basal defects proposed by Goldsmith and Graf in 1958 to explain nonstoichiometry in dolomite. This dolomite from the Nopah Range was formed by deep burial replacement of micritic limestone, and its peculiar superstructure is tentatively attributed to the late diagenetic conditions during replacement.     

Earthquakes, active faults, and geothermal areas in the imperial valley, california

A dense seismograph network in the Imperial Valley recorded a series of earthquake swarms along the Imperial and Brawley faults and a diffuse pattern of earthquakes along the San Jacinto fault. Two known geothermal areas are closely associated with these earthquake swarms. This seismicity pattern demonstrates that seismic slip is occurring along both the Imperial-Brawley and San Jacinto fault systems.     

Spasmodic tremor and possible magma injection in long valley caldera, eastern california

Intensive microearthquake swarms with the appearance of volcanic tremor have been observed in the southwest part of Long Valley caldera, southeastern California. This activity, possibly associated with magma injection, began 6 weeks after several strong (magnitude 6+) earthquakes in an area south of the caldera and has continued sporadically to the present time. The earthquake sequence and magmatic activity are part of a broad increase in tectonic activity in a 15,000-square-kilometer region surrounding the "White Mountains seismic gap," an area with high potential for the next major earthquake in the western Great Basin.     

Magmatic resurgence in long valley caldera, california: possible cause of the 1980 mammoth lakes earthquakes

Changes in elevation between 1975 and October 1980 along a leveling line across the Long Valley caldera indicate a broad (half-width, 15 kilometers) uplift (maximum, 0.25 meter) centered on the old resurgent dome. This uplift is consistent with reinflation of a magma reservoir at a depth of about 10 kilometers. Stresses generated by this magmatic resurgence may have caused the sequence of four magnitude 6 earthquakes near Mammoth Lakes in May 1980.     

High photosynthetic capacity of a winter annual in death valley

Camissonia claviformis, a winter annual of Death Valley, California, that fixes carbon dioxide by the C(3) mechanism, has an in situ photosynthetic rate at midday in spring of nearly 6 nanomoles of carbon dioxide per square centimeter per second-an exceptionally high rate. Camissonia fixes absorbed noon sunlight in the 400- to 700-nanometer region into chemical energy with an efficiency of 8.5 percent, which is 80 percent of that theoretically possible for intact leaves. This performance is primarily due to an unusual capacity to utilize high irradiances. Factors associated with this include a high stomatal conductance to carbon dioxide and high levels of soluble protein and ribulose-1,5-diphosphate carboxylase.     

干热河谷牛角瓜苗期光合生理特性的种源间差异

为了解干热河谷不同种源牛角瓜Calotropis gigantea苗期的光合生理特性,比较分析了牛角瓜幼苗净光合速率(P_n),气孔导度(G_s),胞间二氧化碳摩尔分数(C_i),蒸腾速率(T_r),水分利用效率(W_UE),光能利用效率(L_UE),瞬时羧化效率(C_E)和气孔限制值(l_s)在元江、红河、个旧、建水、元阳等种源间的日变化动态与日均值差异。牛角瓜5个种源的P_n日变化动态均呈双峰曲线,但在不同时刻的数值存在种源间差异。牛角瓜对高温具有极强的适应性,它通过增加气孔导度和蒸腾作用来提高光合同化效率。干热河谷的极端高温不是影响牛角瓜幼苗光合作用与羧化反应的限制因素,而正午的强光辐射显著抑制了牛角瓜幼苗的光合作用与水分利用。干热河谷牛角瓜不同种源间的光合生理参数日均值具有显著差异(P＜0.05),红河种源的P_n,T_r,L_UE和C_E显著高于其他4个种源(P＜0.05),个旧种源表现出“高光合、低蒸腾”的显著特点,具有最高的W_UE和较高的P_n,L_UE和C_E,因此筛选出红河、个旧为具有高水平光合生产与水分利用潜力的干热河谷牛角瓜种质资源。图3表1参43     

Climate-related, long-term faunal changes in a california rocky intertidal community

Changes in the invertebrate fauna of a California rocky intertidal community between the period 1931 to 1933 and the period 1993 to 1994 indicate that species' ranges shifted northward, consistent with predictions of change associated with climate warming. Of 45 invertebrate species, the abundances of eight of nine southern species increased and the abundances of five of eight northern species decreased. No trend was evident for cosmopolitan species. Annual mean shoreline ocean temperatures at the site increased by 0.75 degrees C during the past 60 years, and mean summer maximum temperatures from 1983 to 1993 were 2.2 degrees C warmer than for the period 1921 to 1931.     

Catastrophic storms, el nino, and patch stability in a southern california kelp community

Strong winter storms in southern California destroyed most of the canopy ofthe giant kelp Macrocystis pyrifera but not the patches of understory kelps in the Point Loma kelp forest near San Diego. Subsequent massive recruitment of Macrocystis juveniles and adults that survived the storms had low survival in the summer during the California El Ni?o of 1983. The combined disturbance may have long-lasting structural consequences for this community because, once established, the understory patches can resist invasion by Macrocystis.     

玉米大面积高产综合技术研究与作物全息栽培学的应用

介绍了作物全息栽培学的概念、原理及其对全息栽培学的理解与在作物大面积高产综合技术研究中的应用     

干热河谷区覆盖方式对夏玉米农田土壤温度的影响

对西南干热河谷地区夏玉米农田土壤在不同覆盖方式下其温度变化影响进行了研究,结果表明,不同覆盖方式下,旱地玉米农田土壤温度变化情况呈现出差异性。在0~25 cm土层范围内,夏玉米生育前期秸秆覆盖土壤日均温度比裸地要低,而地膜覆盖土壤日均温度要高于裸地,到了生育后期,不同覆盖方式下的土壤温度日均差异明显降低,其中以地膜覆盖方式下的土壤目平均温度变化最小;土壤温度随土层加深变化幅度逐渐减小,且不同覆盖方式下的温度变化逐渐趋于一致,其中地膜覆盖的增温缓温作用优于秸秆覆盖;土壤温度的变化与气温的相关函数均呈正向相关性,但随土壤深度增加,相关性减弱;最后通过比较产量数据,得出稳定的土壤温度有利于提高夏玉米产量,且地膜覆盖方式在增产增收方面具有显著优势。     

Barium in southern california coastal waters: a potential indicator of marine drilling contamination

The present barium content of Southern California coastal waters was determined to be 11 to 22 micrograms per kilogram of seawater. These values may be used as base-line concentrations to monitor marine contamination during future off-shore oil and gas explorations.     

Photosynthetic performance of switchgrass and its relation to field productivity:A three-year experimental appraisal in semiarid Loess Plateau

To reveal photosynthetic characteristics and biomass yield is important for evaluating introduced species adaptation to local environments. A field experiment was conducted over three consecutive years(2011–2013) to evaluate photosynthetic characteristics, soil water content, aboveground biomass accumulation, and water use efficiency(WUE) in switchgrass(Panicum virgatum L.) populations exposed to three row spacing(20, 40 and 60 cm) treatments in two growth months(June and August) on the semiarid Loess Plateau of China. Results indicated that net photosynthetic rate(P_n), transpiration rate(T_r), instantaneous water use efficiency(WUEi) and plant height of switchgrass showed an increased trend, but aboveground biomass production and WUE showed an decreased trend with enlarged row spacings over the three years. The maximum daily mean Pn values(17.9, 18.4 and 19.7 μmol CO_2 m~(-2) s~(-1)) were observed in 2011, and the highest aboveground biomass production(67 771.8, 6 976.8 and 6 609.2 kg ha~(-1)) were recorded in 2012 for 20, 40 and 60 cm, respectively. A close correlation between tiller numbers and aboveground biomass production(r=0.907) was observed. Pn was positively and significantly correlated with biomass per tiller, but it showed a negative correlation with aboveground biomass production. Our results confirm that wide row spacing is beneficial for single plant development, while narrow row spacing favors biomass production and water use of switchgrass in the region. It also implies that single leaf growth and performance could explain the switchgrass community density differences, while fails to account for the aboveground biomass production.     

Infrared spectral emittance in geological mapping: airborne spectrometer data from pisgah crater, california

Measurements of spectral emittance in the infrared region from 6.8 to 13.3 micrometers were made with an airborne spectrometer at a rate of six spectra per second, on flights 650 meters above the olivine basalt flows at Pisgah Crater in the southern Californian desert. The spectra show chemical and mineralogical differences that can be related to differences in the terrain below the aircraft.     

Remote sensing of soybean canopy as a tool to map high pH, calcareous soils at field scale

Soybean (Glycine max Merr.) is extensively grown in areas of the US Corn Belt where soils often range from relatively acid (pH < 6) to alkaline, calcareous. Iron availability decreases with increase in pH, consequently, soybean can suffer from iron deficiency chlorosis on high pH, calcareous areas of the field. The extent of those areas sometimes can be significant, but they often occur in complex and discontinuous patterns. The objective of the research was to explore how remote sensing of soybean canopies and GIS technologies could be used to map and quantitatively describe the extent of high pH, calcareous soils at field scale. Aerial images that consisted of visible red, green, blue, and near infrared bands were used to calculate green normalized difference vegetative index (GNDVI) and to guide plant and soil sampling at 10 fields during 2003 and 2004 growing seasons. Ten to 18 sampling areas were selected on each field to include a wide range in GNDVI values. Soil samples were analyzed for pH and calcium carbonate equivalent (CCE). Plant samples were used to estimate grain yields. Soil pH and CCE were significantly correlated with GNDVI values in eight and seven sites, respectively. A previously developed alkalinity stress index (ASI), which combines pH and CCE in one value, was significantly related to GNDVI at all 10 sites. Remote sensing of soybean canopy was shown to be a promising tool that can be used to quantitatively describe distribution of alkaline soils at field scale.     

Fault zone connectivity: slip rates on faults in the san francisco bay area, california

The slip rate of a fault segment is related to the length of the fault zone of which it is part. In turn, the slip rate of a fault zone is related to its connectivity with adjoining or contiguous fault zones. The observed variation in slip rate on fault segments in the San Francisco Bay area in California is consistent with connectivity between the Hayward, Calaveras, and San Andreas fault zones. Slip rates on the southern Hayward fault taper northward from a maximum of more than 10 millimeters per year and are sensitive to the active length of the Maacama fault.     

高产、多抗、广适、优质小麦新品种信阳234的选育

信阳 2 34是信阳市农业科学研究所针对豫南稻茬麦区小麦生育期间持续低温、阴雨寡照、湿害渍害重、多种病害频繁交错发生且较重、后期高温高湿逼熟的生态环境 ,采取杂交育种与系谱法选择相结合的方法选育而成的小麦新品种。具有产量潜力大、商品品质好、抗多种病害、适应性广、生长繁茂、群体自身调节能力强、耐旱耐湿、耐肥抗倒、耐后期高温高湿环境、落黄好等特点。 2 0 0 3年通过河南省农作物品种审定委员会审定。1　亲本来源与选育过程通过对国内外数百份种质资源进行观察鉴定和综合评价分析 ,应用性状互补原理和亲本选配原则 ,于 1 992…     

高压静电场在香葱种子分选上的应用初探

香葱种子落入高压静电场中 ,受场强的作用 ,沿电场方向产生位移 ,根据种子粒重不同 ,分布的区域也不同 ,位移距离较小的种子粒重较大 ,种子活力高 ,电导率低。随着分布区间不同 ,种子活力呈现有规律的变化。因此 ,利用高压静电场选种可作为香葱种子分选的一种有效途径。