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4种水鸟途经北京的新记录 总被引:2,自引:1,他引:1
自 1 987年《北京鸟类志》出版以来 ,陆续又有一些北京地区鸟类的新分布记录。 2 0 0 3~ 2 0 0 4年 ,我们在开展“北京地区生物多样性现状与可持续发展规划方案研究”项目研究时又发现了 4种北京地区尚未记述过的鸟类。现报道如下。1 .阔嘴鹬 (Limicolafalcinellus)2 0 0 3年 9月 1 8日约 1 5 :0 0时 ,在北京市延庆野鸭湖湿地自然保护区记录到 1只亚成体水鸟。该鸟体型似滨鹬类 ,但喙基宽阔 ,喙长而尖端下弯 ;羽色似沙锥 ,具白色眉纹和黑色过眼纹。经照片鉴定 ,该鸟为阔嘴鹬的亚成体。阔嘴鹬繁殖于欧亚大陆北部 ,越冬于地中海、红海、印度… 相似文献
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2018年12月31日,于陕西省渭南市大荔县黄河湿地观鸟时,在一鱼塘(110°12’15. 69″E,34°56’43. 99″N,海拔339 m)内观察到1只鸻鹬(图1)在泥滩上与鹤鹬Tringa erythropus、反嘴鹬Recurvirostra avosetta和绿翅鸭Anas crecca等水鸟一同觅食。使用单反相机(NIKON D810与SIGMA S150-600变焦镜头)拍照,观察到其嘴黑褐色,长且直,基部偏黄绿色,虹膜褐色,全身呈灰色,具淡色的眉纹和深色的贯眼纹,背、肩和两翼覆羽具深色羽轴,尾及尾下覆羽具黑色横斑,腹部白色,脚黄绿色。 相似文献
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西藏墨脱县发现长尾阔嘴鸟 总被引:3,自引:2,他引:1
正2015年10月21日,在西藏自治区墨脱县德兴乡(29°20′9.97″N,95°19′13.20″E,海拔780 m)观察到阔嘴鸟2只,该鸟体长约25 cm,顶冠及颈背黑色,头顶具蓝色小点斑,喙呈黄绿色,脸及喉部呈黄色,眼后有一黄色点斑,体呈绿色且两翼有蓝斑,尾呈楔形(图1),经鉴定为长尾阔嘴鸟(Psarisomus dalhousiae)。MacK innon等(2000)认为该鸟种分布于西藏东南部,而Bruce(2003)在《世界鸟类手册》中引用了前者的描述。然而,因缺乏实际观察记录,之后我国鸟类学者的著作中均未将长尾阔嘴鸟列为在西藏有分布的鸟类(郑光美2011)。虽 相似文献
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<正>笔者于2012年5月5日11∶48,在黑龙江省大庆市龙凤湿地自然保护区(51°23'28.2″N,122°03'32.9″E)拍摄到1只长嘴半蹼鹬Limnodromus scolopaceus,经查阅《黑龙江省鸟类志》《东北鸟类》《东北鸟类图鉴》《中国鸟类区系纲要》《吉林省野生动物图鉴(鸟类)》《辽宁省动物志(鸟类)》《中国鸟类分布与分布名录(第2版)》等文献资料后认定,长嘴半蹼鹬为东北地区的鸟类新纪录。拍摄时该鸟正在觅食。该鸟体长约30 cm。嘴长而直,约9 cm,黑色,嘴基部较前端颜色略淡一些。具白色眼圈、黑棕色贯眼纹。背部呈黑、褐色 相似文献
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Masamitsu Doi Yoshinori Nishi Susumu Uchiyama Yuji Nishiuchi Hideki Nishio Takashi Nakazawa Tadayasu Ohkubo Yuji Kobayashi 《Journal of peptide science》2005,11(10):609-616
For the rational design of a stable collagen triple helix according to the conventional rule that the pyrrolidine puckerings of Pro, 4-hydroxyproline (Hyp) and 4-fluoroproline (fPro) should be down at the X-position and up at the Y-position in the X-Y-Gly repeated sequence for enhancing the triple helix propensities of collagen model peptides, a series of peptides were prepared in which X- and Y-positions were altogether occupied by Hyp(R), Hyp(S), fPro(R) or fPro(S). Contrary to our presumption that inducing the X-Y residues to adopt a down-up conformation would result in an increase in the thermal stability of peptides, the triple helices of (Hyp(S)-Hyp(R)-Gly)(10) and (fPro(S)-fPro(R)-Gly)(10) were less stable than those of (Pro-Hyp(R)-Gly)(10) and (Pro-fPro(R)-Gly)(10), respectively. As reported by B?chinger's and Zagari's groups, (Hyp(R)-Hyp(R)-Gly)(10) which could have an up-up conformation unfavorable for the triple helix, formed a triple helix that has a high thermal stability close to that of (Pro-Hyp(R)-Gly)(10). These results clearly show that the empirical rule based on the conformational preference of pyrrolidine ring at each of X and Y residues should not be regarded as still valid, at least for predicting the stability of collagen models in which both X and Y residues have electronegative groups at the 4-position. 相似文献
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A novel blue‐emitting Sr3.5Y6.5O2(PO4)1.5(SiO4)4.5:Eu2+ phosphor was synthesized via a solid‐state reaction. Powder X‐ray diffraction (XRD) analysis demonstrated that the Sr3.5Y6.5O2(PO4)1.5(SiO4)4.5 host had a hexagonal crystal structure in the space group P63/m and unit cell parameters a = 9.418 Å, c = 6.900 Å. The as‐prepared phosphor showed a blue emission and all the main emission peaks were located at around 466 nm for different excitation wavelengths of 297, 333 and 391 nm. The temperature dependence of the photoluminescence property was investigated in the range 20–250 °C, and the emission intensity decreased to 71% of the initial value at room temperature on increasing the temperature to 150 °C. According to the classical theory of fluorescent thermal quenching, the activation energy (ΔE) for the thermal quenching luminescence of the as‐prepared Sr3.45Y6.5O2(PO4)1.5(SiO4)4.5:0.05Eu2+ phosphor was determined to be 0.20 eV. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Pérez-Pantoja D Guzmán L Manzano M Pieper DH González B 《Applied and environmental microbiology》2000,66(4):1602-1608
The enzymes chlorocatechol-1,2-dioxygenase, chloromuconate cycloisomerase, dienelactone hydrolase, and maleylacetate reductase allow Ralstonia eutropha JMP134(pJP4) to degrade chlorocatechols formed during growth in 2,4-dichlorophenoxyacetate or 3-chlorobenzoate (3-CB). There are two gene modules located in plasmid pJP4, tfdC(I)D(I)E(I)F(I) (module I) and tfdD(II)C(II)E(II)F(II) (module II), putatively encoding these enzymes. To assess the role of both tfd modules in the degradation of chloroaromatics, each module was cloned into the medium-copy-number plasmid vector pBBR1MCS-2 under the control of the tfdR regulatory gene. These constructs were introduced into R. eutropha JMP222 (a JMP134 derivative lacking pJP4) and Pseudomonas putida KT2442, two strains able to transform 3-CB into chlorocatechols. Specific activities in cell extracts of chlorocatechol-1,2-dioxygenase (tfdC), chloromuconate cycloisomerase (tfdD), and dienelactone hydrolase (tfdE) were 2 to 50 times higher for microorganisms containing module I compared to those containing module II. In contrast, a significantly (50-fold) higher activity of maleylacetate reductase (tfdF) was observed in cell extracts of microorganisms containing module II compared to module I. The R. eutropha JMP222 derivative containing tfdR-tfdC(I)D(I)E(I)F(I) grew four times faster in liquid cultures with 3-CB as a sole carbon and energy source than in cultures containing tfdR-tfdD(II)C(II)E(II)F(II). In the case of P. putida KT2442, only the derivative containing module I was able to grow in liquid cultures of 3-CB. These results indicate that efficient degradation of 3-CB by R. eutropha JMP134(pJP4) requires the two tfd modules such that TfdCDE is likely supplied primarily by module I, while TfdF is likely supplied by module II. 相似文献
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R M Wartell 《Biopolymers》1972,11(4):745-759
Helix–coil transition curves are calculated for poly (dA) poly(dT) and poly (dA-dT) poly (dA-dT) using the integral equation approach of Goel and Montroll.5 The transitions are described by the loop entropy model with the exponent of the loop entropy factor, k, remaining an arbitrary constant. The theoretical calculations are compared with experimental transition curves of the two polymers. Results indicate that the stacking energies for these two polymers differ by about 1 kcal/mole of base pairs. Also, a fit between theory and experiment was not possible for k > 1.70. 相似文献
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We analysed the endogenous cytokinin levels of Dendrobium Madame Thong-In seedlings grown in vitro during vegetative and flowering-inductive periods. HPLC was used to fractionate the extracts and radioimmunoassay (RIA) was used for assay of zeatin (Z), dihydrozeatin (DZ), N(6)-(Delta(2)-isopentenyl)-adenine (iP) and their derivatives. Coconut water used in experiments was found to contain high level (>136 pmol ml(-1)) of zeatin riboside (ZR). Protocorms and seedlings cultured in medium with coconut water were found to contain 0.5-3.9 pmol g(-1) FW of the cytokinins analysed. Seedlings (1.0-1.5 cm) cultured in flowering-inductive liquid medium containing 6-benzyladenine (BA, 4.4 muM) and coconut water (CW, 15%) contained up to 200 and 133 pmol g(-1) FW of iP and iPA, respectively. These levels were significantly higher than all other cytokinins analysed in seedlings of the same stage and were about 80- to 150-folds higher than seedlings cultured in non-inductive medium. During the transitional (vegetative to reproductive) stage, the endogenous levels of iP (178 pmol g(-1) FW) and iPA (63 pmol g(-1) FW) were also significantly higher than cytokinins in the zeatine (Z) and dihydrozeatin (DZ) families in the same seedlings. Seedlings that grew on inductive medium but remained vegetative contained lower levels of iPA. The importance of the profiles of iP and its derivatives in induction of in vitro flowering of D. Madame Thong-In is discussed. 相似文献
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The biology of the fruit fly Bactrocera tau, an important horticultural pest, was studied under laboratory conditions at 25°C and 60–70% relative humidity on Cucurbita maxima. The duration of mating averaged 408.03 ± 235.93 min. After mating, the female fly had a preoviposition period of 11.7 ± 4.49 days. The oviposition rate was 9.9 ± 8.50 eggs and fecundity was 464.6 ± 67.98 eggs/female. Eggs were elliptical, smooth and shiny white, turning darker as hatching approached, and measured 1.30 ± 0.07 mm × 0.24 ± 0.04 mm. The chorion has polygonal microsculpturing and is species-specific with polygonal walls. The egg period lasts for 1.3 ± 0.41 days. The duration of the larval period is 1.2 ± 0.42, 1.7 ± 0.48 and 4.0 ± 0.94 days for first, second and third instars, respectively. Pupation occurs in the sand or soil and pupal periods are 7.0 ± 0.47 days. The life cycle from egg to adult was completed in 14.2 ± 1.69 days; the longevity of mated females and males was 130.33 ± 14.18 and 104.66 ± 31.21 days, respectively. At least two to three generations were observed from June 2008 to June 2009. 相似文献
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Nageswara Raju C Adinarayana Reddy C Sailaja S Seo HJ Sudhakar Reddy B 《Luminescence》2012,27(5):334-340
This article reports on the optical properties of Er3+ ions doped CdO–Bi2O3–B2O3 (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd–Ofelt theory, the intensity parameters Ωλ (λ = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er3+:CdBiB glasses. The concentration quenching and energy transfer from Yb3+–Er3+ were explained. The stimulated emission cross‐section, full width at half maximum (FWHM) and FWHM × values are also calculated for all the Er3+:CdBiB glasses. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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The formation of cationic palladium(II)complexes [TrpyPdII]+X− by salt metathesis of the respective trifluoroacetates with different salts of weakly coordinating anions X− was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear complexes are observed depending on the nature of the anion X− and the solvent. The mononuclear cations, which are only formed with X = BArF, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of PdII. When treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base adducts [TrpyPdIIL]+ with L = CH3NC, tBuNH2, PMe3, PEt3 and PiPr3 and [TrpyPdIIL2]+ with L = PMe3 were prepared from the mononuclear cations [TrpyPdII]+BArF−. From structural studies it becomes apparent, that the formation of stable five coordinate PdII species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the strain, which is induced on the TrpyPdII unit. 相似文献