Radar soundings of the subsurface of Mars   总被引：2，自引：0，他引：2  

Picardi G  Plaut JJ  Biccari D  Bombaci O  Calabrese D  Cartacci M  Cicchetti A  Clifford SM  Edenhofer P  Farrell WM  Federico C  Frigeri A  Gurnett DA  Hagfors T  Heggy E  Herique A  Huff RL  Ivanov AB  Johnson WT  Jordan RL  Kirchner DL  Kofman W  Leuschen CJ  Nielsen E  Orosei R  Pettinelli E  Phillips RJ  Plettemeier D  Safaeinili A  Seu R  Stofan ER  Vannaroni G  Watters TR  Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.  相似文献   

1986—1995年我国造纸科学论文作者统计分析     

雷阿莉  李宁 《西北林学院学报》1996,11(3):91-95

本文利用数理统计的方法，得出１９８６～１９９５年间我国造纸科学论文作者服从洛特卡分布的结论，又根据普赖斯以发文量多少确定科学家的原理，确定出了我国造纸科学的活跃著者群，并对此进行了分析  相似文献   

Reduction to homozygosity of genes on chromosome 11 in human breast neoplasia   总被引：28，自引：0，他引：28  

I U Ali  R Lidereau  C Theillet  R Callahan 《Science (New York, N.Y.)》1987,238(4824):185-188

The somatic loss of heterozygosity for normal alleles occurring in human tumors has suggested the presence of recessive oncogenes. The results presented here demonstrate a loss of heterozygosity of several genes on chromosome 11 in primary breast tumors. Restriction fragment length polymorphism analysis of these DNAs further suggests that the most frequent loss of sequences in breast tumors occurs between the beta-globin and parathyroid hormone loci on the short arm of chromosome 11. The loss of heterozygosity for chromosome 11 loci has a significant association with tumors that lack estrogen and progesterone receptors, grade III tumors, and distal metastasis.  相似文献   

Phosphorylation and regulation of Akt/PKB by the rictor-mTOR complex   总被引：2，自引：0，他引：2  

Sarbassov DD  Guertin DA  Ali SM  Sabatini DM 《Science (New York, N.Y.)》2005,307(5712):1098-1101

Deregulation of Akt/protein kinase B (PKB) is implicated in the pathogenesis of cancer and diabetes. Akt/PKB activation requires the phosphorylation of Thr308 in the activation loop by the phosphoinositide-dependent kinase 1 (PDK1) and Ser473 within the carboxyl-terminal hydrophobic motif by an unknown kinase. We show that in Drosophila and human cells the target of rapamycin (TOR) kinase and its associated protein rictor are necessary for Ser473 phosphorylation and that a reduction in rictor or mammalian TOR (mTOR) expression inhibited an Akt/PKB effector. The rictor-mTOR complex directly phosphorylated Akt/PKB on Ser473 in vitro and facilitated Thr308 phosphorylation by PDK1. Rictor-mTOR may serve as a drug target in tumors that have lost the expression of PTEN, a tumor suppressor that opposes Akt/PKB activation.  相似文献   

Estimation of the rootzone depth above a gravel layer (in wild blueberry fields) using electromagnetic induction method     

Fahad S. Khan  Qamar U. Zaman  Young K. Chang  Aitazaz A. Farooque  Arnold W. Schumann  Ali Madani 《Precision Agriculture》2016,17(2):155-167

Wild blueberry (Vaccinium angustifolium Ait.) fields in the north east Canada are naturally grown in a course textured thin layer of soil and below this layer is a soilless layer of gravel. The root zone depth of this crop varies from 10 to 15 cm. Investigating the depth to the gravel layer below the course textured soil is advantageous, as it affects the water holding capacity of the root zone. Water and nutrient management are the two primary determinants of crop yield and the amount of leaching. The objective of this study was to estimate the depth to the gravel layer using DualEM-2 instrument. A C++ program written in Visual Studio 2010 was used to develop mathematical models for estimating the depth to the gravel layer from the outputs of DualEM-2 sensor. Two wild blueberry fields were selected in central Nova Scotia, Canada to evaluate the performance of DualEM-2 instrument in estimating the rootzone depth above the gravel layer. The mid points of squares created by grid lines were used as the sampling points at each experimental site. The actual depth to the interface was measured manually at selected grid points (n = 50). The apparent ground conductivity (EC_a) values of DualEM-2 were recorded and the depth to the interface was estimated for the same sampling points within the selected fields. The fruit yield samples were also collected from the same grid points to identify the impact of the depth to the gravel layer on crop yield. After calibrations, comprehensive surveys were conducted and the actual and estimated depths to the interface were established. The interpolated maps of fruit yield, and the actual (z_in) and estimated (\( {\text{z}}_{\text{in}}^{*} \)) depths to the interface were created in ArcGIS 10 software. Results indicated that the z_in was significantly correlated with \( {\text{z}}_{\text{in}}^{*} \) for the North River (R ² = 0.73; RMSE = 0.27 m) and the Carmel (R ² = 0.45; RMSE = 0.20 m) sites. Results revealed that the areas with shallow depth to the gravel layer were low yielding, indicating that the variation in the depth to the gravel layer can have an impact on crop productivity. Non-destructive estimations of the depth to the gravel layer can be used to develop erosion control strategies, which will result in an increased crop production.  相似文献   

盐胁迫对扁桃砧木营养器官离子吸收的影响     

克热木·伊力  买合木提·卡热  侯江涛 《新疆农业大学学报》2007,30(4):46-51

温室条件下,用NaCl和Na2SO4处理石头扁桃、桃扁桃和毛桃,处理浓度为0,75,150,300和350 mmol/L,处理10,20 d分别取叶、根和茎,测定各器官中离子吸收与分布变化规律。研究结果表明,盐胁迫下,3种砧木根、茎、叶中Na ,Cl-,SO42-含量及Na /K 比均随盐浓度的增加和处理时间的延长而增加,K 含量变化规律不稳定,但桃扁桃根、茎和叶片中K 略高于其他两个品种;石头扁桃根、茎、叶片中Na /K 比值高于其它两个品种,桃扁桃中Na /K 比值最低。桃扁桃根部Na ,Cl-和SO42-含量高于石头扁桃和毛桃,而叶片和茎中Na ,Cl-和SO42-含量却低于石头扁桃和毛桃。桃扁桃根部能够积累较多的Na ,阻止和减少了Na 向地上部的运输,从而减轻了Na2SO4对它的伤害,进而表明了桃扁桃耐盐能力较强。  相似文献   

盐胁迫对扁桃砧木叶片SOD、POD和CAT活性的影响   总被引：4，自引：0，他引：4  

买合木提&#;卡热  克热木&#;伊力  吾甫尔&#;巴拉提 《西北农业学报》2005,14(6):96-101

以温室盆栽的3种扁桃砧木为材料,研究了不同浓度的NaCl、Na2SO4和不同胁迫时间对其叶片活性氧代谢变化的影响.结果表明:NaCl和Na2SO4胁迫下,石头扁桃,桃扁桃和毛桃叶片中POD、CAT活性均随盐浓度的增加而升高,而随着盐胁迫时间的延长其活性有所下降,但都高于对照.SOD活性均随盐浓度的增加先升高后下降,而且后期下降幅度很大.与NaCl胁迫相比,Na2SO4胁迫下这3种砧木叶片中POD、CAT和SOD活性低.从2种盐胁迫下POD、CAT和SOD活性变化规律初步判断这3种砧木的抗盐能力强弱为桃扁桃＞毛桃＞石头扁桃.  相似文献   

Physico-chemical characteristics of apricot (Prunus armeniaca L.) grown in Northern Areas of Pakistan     

Sartaj Ali  Tariq Masud  Kashif Sarfraz Abbasi 《Scientia Horticulturae》2011

In order to ascertain physico-chemical, functional and geometrical traits of apricot fruit from Northern Areas of Pakistan, six predominantly grown varieties namely, Alman, Habi, Khakhas, Mirmalik, Neeli and Shai were selected in this study. Proximate composition as crude fat (2.1–3%), crude protein (6.18–8.7%), crude fiber (11.85–13.6%), ash (9.45–12.1%) and total sugars (56.8–64.9%) were determined on dry weight basis. The data showed variations among the investigated parameters in all varieties. Functional properties of apricot fruit viz. ascorbic acid (67.39–90.94 mg/100 g), total phenolic compounds (4590–7310 mgGAE/100 g), total carotenoids (10.09–18.13 mg/100 g β-carotene) and antioxidant activity (56.84–82.33%) were also recorded. The data pertaining to mineral contents (mg/100 g) revealed K as the predominant element (2040–3000) followed by P, Mg, Ca, Na and Fe among all the tested samples. Furthermore, geometrical characters of apricot varieties were also determined as important sensory and technological attributes on fresh weight basis. The result from the present study showed that all the tested varieties are highly nutritious and rich in functional components.  相似文献   

Molecular analysis of Iranian seedless barberries via SSR     

Mehdi Rezaei  Ali Ebadi  Stefanie Reim  Reza Fatahi  Ahmad Balandary  Naser Farrokhi  Magda-Viola Hanke 《Scientia Horticulturae》2011

  相似文献   

Preference and performance of <Emphasis Type="Italic">Plutella xylostella</Emphasis> (L.) (Lepidoptera: Plutellidae) on canola cultivars     

Seyed Ali Asghar Fathi  Maryam Bozorg-Amirkalaee  Rana Muhammad Sarfaraz 《Journal of pest science》2011,84(1):41-47

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is an important insect pest of canola, Brassica napus L., in Ardabil, Iran. Host plant resistance is an essential component of integrated management of P. xylostella. We investigated the preferences and performance of P. xylostella on nine commercial cultivars of canola, namely Zarfam, RGS003, Adder, Okapi, Opera, Hyola401, Ebonite Option500 and Elite under greenhouse conditions at 23 ± 1°C, 50 ± 5% RH and 14L:10D. In free-choice situation, oviposition was lowest on Opera (23.5) and highest on Zarfam (44.7). In the life table study, fecundity of new generation female moths was lowest on Opera (95.4) and highest on Adder (145.7). Survival from egg to adult was significantly lower on Opera, Option500 and Hyola401 than on other tested cultivars. The intrinsic rate of natural increase (r _m) and population growth rate (λ) were lowest on Opera and highest on Zarfam. The generation time (T) was shortest on Zarfam (17.2 days) and longest on Hyola401 (19.9 days) whereas doubling time (DT) was longest on Opera (3.9 days) and shortest on Zarfam (3.0 days). Our results clearly suggest that Opera was the most resistant host among the tested cultivars and has the potential to be used in the integrated management of P. xylostella.  相似文献