894 resultados para Virgilio Marón, Publio, 70-19 a. C..
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Mencin de tomo tomada del pie de pág
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Mode of access: Internet.
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Académico - Licenciaturas
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Académico - Licenciaturas
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Entre los modelos literarios que, en las epopeyas quinientistas acerca de la conquista de México, sirven para dar forma épica a la materia histórica tomada de las crnicas, la Eneida de Virgilio desempeña un papel fundamental. En el presente artículo se pretende mostrar cómo la identificación de Jerónimo de Aguilar con el Aqueménides virgiliano, que se encuentra por primera vez en el Carlo famoso de Luis Zapata, reaparece en Francisco de Terrazas, en Gabriel Lobo Lasso de la Vega y en Antonio de Saavedra Guzmán, así como proponer algunas consideraciones acerca de las relaciones que se hayan podido dar entre las obras de estos poetas.
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Resumen: No momento em que a Eneida foi composta, entre os anos 29 e 19 a.C, a memória da divinizaão de César se fazia presente, lançando também a expectativa sobre a consecratio do próprio Imperador. No poema épico, o prenúncio da apoteose de Augusto surge na mesma profecia em que Júpiter assegura a Vênus a acolhida de seu filho, Enéias, entre os imortais (VIRGÍLIO, Eneida, I.259- 289). Este tema reaparece nas Metamorfoses de Ovídio cujas linhas finais do livro XV retratam a transformaão de Júlio César em astro – sidus - e mencionam o dia em que o Princeps deverá receber, nos céus, as preces de seus governados (OVÍDIO, Metamorfoses, XV.745-879). Tendo em vista a instituição do culto imperial, problematizaremos nas obras mencionadas as relaões entre mito, memória e poder no Principado.
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In a recent study, we demonstrated the immunogenic properties of a new malaria vaccine polypeptide based on a 19 kDa C-terminal fragment of the merozoite surface protein-1 (MSP1(19)) from Plasmodium vivax and an innate immunity agonist, the Salmonella enterica serovar Typhimurium flagellin (FliC). Herein, we tested whether the same strategy, based on the MSP1(19) component of the deadly malaria parasite Plasmodium falciparum, could also generate a fusion polypeptide with enhanced immunogenicity. The His(6)FliC-MSP1(19) fusion protein was expressed from a recombinant Escherichia coil and showed preserved in vitro TLR5-binding activity. In contrast to animals injected with His(6)MSP1(19), mice subcutaneously immunised with the recombinant His6FliC-MSP1(19) developed strong MSP1(19)-specific systemic antibody responses with a prevailing IgG1 subclass. Incorporation of other adjuvants, such as CpG ODN 1826, complete and incomplete Freund`s adjuvants or Quil-A, improved the IgG responses after the second, but not the third, immunising dose. It also resulted in a more balanced IgG subclass response, as evaluated by the IgG1/IgG2c ratio, and higher cell-mediated immune response, as determined by the detection of antigen-specific interferon-gamma secretion by immune spleen cells. MSP(19)-specific antibodies recognised not only the recombinant protein, but also the native protein expressed on the surface of P. falciparum parasites. Finally, sera from rabbits immunised with the fusion protein alone inhibited the in vitro growth of three different P. falciparum strains. In summary, these results extend our previous observations and further demonstrate that fusion of the innate immunity agonist FliC to Plasmodium antigens is a promising alternative to improve their immunogenicity. (c) 2010 Elsevier Ltd. All rights reserved.
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Deeply conflicting views on the political situation of Judaea under the Roman prefects (6-41 c.e.) have been offered. According to some scholars, this was a period of persistent political unrest and agitation, whilst according to a widespread view it was a quiescent period of political calm (reflected in Tacitus’ phrase sub Tiberio quies). The present article critically examines again the main available sources –particularly Josephus, the canonical Gospels and Tacitus– in order to offer a more reliable historical reconstruction. The conclusions drawn by this survey calls into question some widespread and insufficiently nuanced views on the period. This, in turn, allows a reflection on the non-epistemic factors which might contribute to explain the origin of such views.
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We present a method for differential ratiometric measurement of reflectance change due to molecular adsorption using a diffractive microstructure fabricated on a reflectance contrast enhancing substrate for bulk refractometry and surface molecular binding detection applications. The differential method suppresses signal fluctuations due to thermal or concentration gradients in the sample flow cell by more than 40x and enables the real-time measurement of molecular interactions on the surface with a noise floor of about 70 pm. (V)C 2012 American Institute of Physics. http://dx.doi.org/10.1063/1.4766190]
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Aldimines react with reducing agents, such as Grignards, phenylsilane or zinc in the presence of titanium(IV) isopropoxide to form amines and reductively coupled imines (diamines). Using deuterium labeled reagents, the mechanism of reduction to form amines is described. Reducing agents, such as the Grignard and zinc result in the formation of low valent titanium (LVT), which in turn reduces the imine. On the other hand, phenylsilane reacts by a distinctly different mechanism and where a hydrogen atom from silicon is directly transferred to the titanium coordinated imine. (c) 2014 Elsevier Ltd. All rights reserved.
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Executive Summary: The western National Coastal Assessment (NCA-West) program of EPA, in conjunction with the NOAA National Ocean Service (NOS), conducted an assessment of the status of ecological condition of soft sediment habitats and overlying waters along the western U.S. continental shelf, between the target depths of 30 and 120 m, during June 2003. NCA-West and NOAA/NOS partnered with the West Coast states (Washington (WA), Oregon (OR), and California (CA)), and the Southern California Coastal Water Research Project (SCCWRP) Bight ’03 program to conduct the survey. A total of 257 stations were sampled from Cape Flattery, WA to the Mexican border using standard methods and indicators applied in previous coastal NCA projects. A key study feature was the incorporation of a stratified-random sampling design with stations stratified by state and National Marine Sanctuary (NMS) status. Each of the three states was represented by at least 50 random stations. There also were a total of 84 random stations located within NOAA’s five NMSs along the West Coast including the Olympic Coast NMS (OCNMS), Cordell Bank NMS (CBNMS), Gulf of Farallones NMS (GFNMS), Monterey Bay NMS (MBNMS), and Channel Islands NMS (CINMS). Collection of flatfish via hook-and-line for fish-tissue contaminant analysis was successful at 50 EMAP/NCA-West stations. Through a collaboration developed with the FRAM Division of the Northwest Fisheries Science Center, fish from an additional 63 stations in the same region and depth range were also analyzed for fish-tissue contaminants. Bottom depth throughout the region ranged from 28 m to 125 m for most stations. Two slightly deeper stations from the Southern California Bight (SCB) (131, 134 m) were included in the data set. About 44% of the survey area had sediments composed of sands (< 20% silt-clay), about 47% was composed of intermediate muddy sands (20-80% silt-clay), and about 9% was composed of muds (> 80% silt-clay). The majority of the survey area (97%) had relatively low percent total organic carbon (TOC) levels of < 2%, while a small portion (< 1%) had high TOC levels (> 5%), in a range potentially harmful to benthic fauna. Salinity of surface waters for 92% of the survey area were > 31 psu, with most stations < 31 psu associated with the Columbia River plume. Bottom salinities ranged only between 31.6 and 34.4 psu. There was virtually no difference in mean bottom salinities among states or between NMS and non-NMS stations. Temperatures of surface water (range 8.5 -19.9 °C) and bottom water (range 5.8 -14.7 °C) averaged several degrees higher in CA in comparison to WA and OR. The Δσt index of watercolumn stratification indicated that about 31% of the survey area had strong vertical stratification of the water column. The index was greatest for waters off WA and lowest for CA waters. Only about 2.6 % of the survey area had surface dissolved oxygen (DO) concentrations ≤ 4.8 mg/L, and there were no values below the lower threshold (2.3 mg/L) considered harmful to the survival and growth of marine animals. Surface DO concentrations were higher in WA and OR waters than in CA, and higher in the OC NMS than in the CA sanctuaries. An estimated 94.3% of the area had bottom-water DO concentrations ≤ 4.8 mg/L and 6.6% had concentrations ≤ 2.3 mg/L. The high prevalence of DO from 2.3 to 4.8 mg/L (85% of survey area) is believed to be associated with the upwelling of naturally low DO water across the West Coast shelf. Mean TSS and transmissivity in surface waters (excluding OR due to sample problems) were slightly higher and lower, respectively, for stations in WA than for those in CA. There was little difference in mean TSS or transmissivity between NMS and non-NMS locations. Mean transmissivity in bottom waters, though higher in comparison to surface waters, showed little difference among geographic regions or between NMS and non-NMS locations. Concentrations of nitrate + nitrite, ammonium, total dissolved inorganic nitrogen (DIN) and orthophosphate (P) in surface waters tended to be highest in CA compared to WA and OR, and higher in the CA NMS stations compared to CA non-sanctuary stations. Measurements of silicate in surface waters were limited to WA and CA (exclusive of the SCB) and showed that concentrations were similar between the two states and approximately twice as high in CA sanctuaries compared to OCNMS or nonsanctuary locations in either state. The elevated nutrient concentrations observed at CA NMS stations are consistent with the presence of strong upwelling at these sites at the time of sampling. Approximately 93% of the area had DIN/P values ≤ 16, indicative of nitrogen limitation. Mean DIN/P ratios were similar among the three states, although the mean for the OCNMS was less than half that of the CA sanctuaries or nonsanctuary locations. Concentrations of chlorophyll a in surface waters ranged from 0 to 28 μg L-1, with 50% of the area having values < 3.9 μg L-1 and 10% having values > 14.5 μg L-1. The mean concentration of chlorophyll a for CA was less than half that of WA and OR locations, and concentrations were lowest in non-sanctuary sites in CA and highest at the OCNMS. Shelf sediments throughout the survey area were relatively uncontaminated with the exception of a group of stations within the SCB. Overall, about 99% of the total survey area was rated in good condition (<5 chemicals measured above corresponding effect range low (ERL) concentrations). Only the pesticides 4,4′-DDE and total DDT exceeded corresponding effect range-median (ERM) values, all at stations in CA near Los Angeles. Ten other contaminants including seven metals (As, Cd, Cr, Cu, Hg, Ag, Zn), 2-methylnaphthalene, low molecular weight PAHs, and total PCBs exceeded corresponding ERLs. The most prevalent in terms of area were chromium (31%), arsenic (8%), 2-methylnaphthalene (6%), cadmium (5%), and mercury (4%). The chromium contamination may be related to natural background sources common to the region. The 2-methylnaphthalene exceedances were conspicuously grouped around the CINMS. The mercury exceedances were all at non-sanctuary sites in CA, particularly in the Los Angeles area. Concentrations of cadmium in fish tissues exceeded the lower end of EPAs non-cancer, human-health-risk range at nine of 50 EMAP/NCA-West and nine of 60 FRAM groundfish-survey stations, including a total of seven NMS stations in CA and two in the OCNMS. The human-health guidelines for all other contaminants were only exceeded for total PCBs at one station located in WA near the mouth of the Columbia River. Benthic species richness was relatively high in these offshore assemblages, ranging from 19 to 190 taxa per 0.1-m2 grab and averaging 79 taxa/grab. The high species richness was reflected over large areas of the shelf and was nearly three times greater than levels observed in estuarine samples along the West Coast (e.g NCA-West estuarine mean of 26 taxa/grab). Mean species richness was highest off CA (94 taxa/grab) and lower in OR and WA (55 and 56 taxa/grab, respectively). Mean species richness was very similar between sanctuary vs. non-sanctuary stations for both the CA and OR/WA regions. Mean diversity index H′ was highest in CA (5.36) and lowest in WA (4.27). There were no major differences in mean H′ between sanctuary vs. nonsanctuary stations for both the CA and OR/WA regions. A total of 1,482 taxa (1,108 to species) and 99,135 individuals were identified region-wide. Polychaetes, crustaceans and molluscs were the dominant taxa, both by percent abundance (59%, 17%, 12% respectively) and percent species (44%, 25%, 17%, respectively). There were no major differences in the percent composition of benthic communities among states or between NMSs and corresponding non-sanctuary sites. Densities averaged 3,788 m-2, about 30% of the average density for West Coast estuaries. Mean density of benthic fauna in the present offshore survey, averaged by state, was highest in CA (4,351 m-2) and lowest in OR (2,310 m-2). Mean densities were slightly higher at NMS stations vs. non-sanctuary stations for both the CA and OR/WA regions. The 10 most abundant taxa were the polychaetes Mediomastus spp., Magelona longicornis, Spiophanes berkeleyorum, Spiophanes bombyx, Spiophanes duplex, and Prionospio jubata; the bivalve Axinopsida serricata, the ophiuroid Amphiodia urtica, the decapod Pinnixa occidentalis, and the ostracod Euphilomedes carcharodonta. Mediomastus spp. and A. serricata were the two most abundant taxa overall. Although many of these taxa have broad geographic distributions throughout the region, the same species were not ranked among the 10 most abundant taxa consistently across states. The closest similarities among states were between OR and WA. At least half of the 10 most abundant taxa in NMSs were also dominant in corresponding nonsanctuary waters. Many of the abundant benthic species have wide latitudinal distributions along the West Coast shelf, with some species ranging from southern CA into the Gulf of Alaska or even the Aleutians. Of the 39 taxa on the list of 50 most abundant taxa that could be identified to species level, 85% have been reported at least once from estuaries of CA, OR, or WA exclusive of Puget Sound. Such broad latitudinal and estuarine distributions are suggestive of wide habitat tolerances. Thirteen (1.2%) of the 1,108 identified species are nonindigenous, with another 121 species classified as cryptogenic (of uncertain origin), and 208 species unclassified with respect to potential invasiveness. Despite uncertainties of classification, the number and densities of nonindigenous species appear to be much lower on the shelf than in the estuarine ecosystems of the Pacific Coast. Spionid polychaetes and the ampharetid polychaete Anobothrus gracilis were a major component of the nonindigenous species collected on the shelf. NOAA’s five NMSs along the West Coast of the U.S. appeared to be in good ecological condition, based on the measured indicators, with no evidence of major anthropogenic impacts or unusual environmental qualities compared to nearby nonsanctuary waters. Benthic communities in sanctuaries resembled those in corresponding non-sanctuary waters, with similarly high levels of species richness and diversity and low incidence of nonindigenous species. Most oceanographic features were also similar between sanctuary and non-sanctuary locations. Exceptions (e.g., higher concentrations of some nutrients in sanctuaries along the CA coast) appeared to be attributable to natural upwelling events in the area at the time of sampling. In addition, sediments within the sanctuaries were relatively uncontaminated, with none of the samples having any measured chemical in excess of ERM values. The ERL value for chromium was exceeded in sediments at the OCNMS, but at a much lower percentage of stations (four of 30) compared to WA and OR non-sanctuary areas (31 of 70 stations). ERL values were exceeded for arsenic, cadmium, chromium, 2- methylnaphthalene, low molecular weight PAHs, total DDT, and 4,4′-DDE at multiple sites within the CINMS. However, cases where total DDT, 4,4′-DDE, and chromium exceeded the ERL values were notably less prevalent at CINMS than in non-sanctuary waters of CA. In contrast, 2-methylnaphthalene above the ERL was much more prevalent in sediments at the CINMS compared to non-sanctuary waters off the coast of CA. While there are natural background sources of PAHs from oil seeps throughout the SCB, this does not explain the higher incidence of 2-methylnaphthalene contamination around CINMS. Two stations in CINMS also had levels of TOC (> 5%) potentially harmful to benthic fauna, though none of these sites exhibited symptoms of impaired benthic condition. This study showed no major evidence of extensive biological impacts linked to measured stressors. There were only two stations, both in CA, where low numbers of benthic species, diversity, or total faunal abundance co-occurred with high sediment contamination or low DO in bottom water. Such general lack of concordance suggests that these offshore waters are currently in good condition, with the lower-end values of the various biological attributes representing parts of a normal reference range controlled by natural factors. Results of multiple linear regression, performed using full model procedures to test for effects of combined abiotic environmental factors, suggested that latitude and depth had significant influences on benthic variables regionwide. Latitude had a significant inverse influence on all three of the above benthic variables, i.e. with values increasing as latitude decreased (p< 0.01), while depth had a significant direct influence on diversity (p < 0.001) and inverse effect on density (p <0.01). None of these variables varied significantly in relation to sediment % fines (at p< 0.1), although in general there was a tendency for muddier sediments (higher % fines) to have lower species richness and diversity and higher densities than coarser sediments. Alternatively, it is possible that for some of these sites the lower values of benthic variables reflect symptoms of disturbance induced by other unmeasured stressors. The indicators in this study included measures of stressors (e.g., chemical contaminants, eutrophication) that are often associated with adverse biological impacts in shallower estuarine and inland ecosystems. However, there may be other sources of humaninduced stress in these offshore systems (e.g., bottom trawling) that pose greater risks to ambient living resources and which have not been captured. Future monitoring efforts in these offshore areas should include indicators of such alternative sources of disturbance. (137pp.) (PDF contains 167 pages)
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本文对北京怀柔汤河口、北京云蒙山、西山以及河北省石家庄地区元氏县的荆条灌丛的群落学特征及其生物量进行了较为详细的研究,并着重研究了汤河口、云蒙山、西山三个亲地的荆条群落的地球化学特征和元素循环特征,对西山的荆条群落中荆条叶片枯落物的分解过程进行了详细的比较研究,最后,对汤河口和西山的两个荆条灌丛的相对稳定性进行了探讨,并和昭田真的演替度进行了比较,期望对荆条灌丛的现况有个较全面和深入的了解,为合理的改造利用广阔的华北落叶灌丛提供理论依据。 本研究设置了四个样地。样地1在北京市怀柔县汤河口乡,样地2在汤河口以南40公里的云蒙山林场,下设两个小样地2a2b,分别经过8年和3年的封山保护。样地3在北京海淀区的西山上,样地4位于河北省元氏县。四个样地的地理位置,地形、立地条件及所受的人为干扰的程度各不相同。DCA析对样地的排序图中从左到右样地的顺序为样地2b,2a样地3,样地1,样地4。 6个样地的荆条滋丛中计有高等植物49种,分属24科47属。其中样地1 8科14种,样地2a 15科24种,样地2b 13科18种,样地3 9科14种,样地4a 11科18种,样地4b 7科11种。以禾本科植物最多(8种),菊科植物6种次之,蔷薇科植物4种,居第三。6个样地中常见植物种(存在度60%以上)有11个,较1965年调查时的常见种数(16种)显著减少。 生活型谱分析表明样地1和2a生活型谱介于热带和温带类型之间。样地2b的生活型谱是较典型的温带类型,样地3则较偏向荒漠类型;样地4a4b的生活型谱则较偏向热带和荒漠的类型。 植物区系分析表明,样地2b带有最明显的中生性,而样地4a含有最多的热带和亚热带分布种而最为干燥。样地依干燥度增加的顺序为2b,2a3,1,4b,4a这个顺序恰好和DCA样地的排序结果完全吻合,同时,它还是温度升高的梯度。 荆条灌丛中荆条地上部生物量,以样地2a2b为最高,分别为3571,9和3285.8公斤/公顷,其次为样地3,达2445.7公斤/公顷,余下的顺序为样地1,样地4a4b。这个顺序和DCA样地的排序结果一致,即荆条地上部生物量随着样地干燥程度的增加和温度的增加而减少。相关分析表明,热量(年日照时数)是控制荆条生长的最主要因素,且荆条的生长受土壤中砾石的很大的制约。 荆条灌丛中荆条之外的其它植物种类,作为一个组分,其地上部生物量除样地1外,和荆条地上部生物量的大小顺序一致,这些植物地上部生物量随人为干扰程度的增强而极显著的减少,且随海拔高度的增加而极显著的增加,说明这些植物较适于生长在海拔较高的地区,且它们随人为干扰的能力很弱。 荆条灌丛群落地上部总生物量,作为上述两个组分的综合,较多的受灌丛中其它植物地上部生物量的影响,而且与海拔高度呈现显著的相关性。群落地上部总生物量与年蒸发量、无霜期、人为干扰程度均表现极显著的负相关,与≥10'C年积温也显著的负相关。这些特点,都表明荆条灌丛一个总趋势,即较低的温低更适合该群落的生长。 荆条地下部生物量在样地l达9641.8公斤,公顷顾(1986) 和l0996.6公斤/公顷(1987),其中各有51.1%和28.90%是根球的生物量,在样地3则1988年为2306.1公斤/公顷,l989年增至5442.2公斤/公顷,两个样地中,地下部生物量为枝条生物量的6.29和5.44倍(样地1),以及2.10和1.23倍《样地3),根枝比的分析表明样地1年龄大于样地3,且样地1比样地3.干燥,荆条的根枝比大于其它灌术种类的根枝比,这是荆条对砍伐的适应.就象灌丛栎(根枝比6.23)对火灾的适应一样。 样地1荆条灌丛的总生物量,1986年为13.44吨/公顷,87年为l6.4吨/公顷,增加了22.2%,群落年净第一性生产量为3.96吨/公顷•年。在群落总生物量中,荆条的生物量占绝大部分,分别达90.4%和86.3%,而在群落年净第一性生产量中,荆条的贡献达3.00吨/公顷•年,占75.8%。 样地3的总生物量88年为9.90砘/公顷.89年猛增至21.17砘/公顷,增加了113.9%,群落年净第一性生产量为12.62砘/公顷•年,是样地1的3.19倍。群落总生物量中,荆条所占的比例在1988年为48.0%,89年增大为58.5%,和样地1的变化趋势相反,表明两个样地的荆条灌丛处于不同的发育阶段。在群落的年净第一性生产量中,荆条的贡献和样地1相似,达71.1%。 和不同类型的灌丛地上部生物量比较的结果表明荆条灌丛小于同地区的落叶灌丛(绒毛绣线菊、荆条、蚂蚱腿子灌丛),更小于同地区的乔木树种的萌生灌丛如辽东栎萌生丛.以及其他地区的矮针叶树栎灌丛,群落总生物量的比较结果也表明荆条灌丛的生物量还有很大的发展潜力。 荆条灌丛地上部生产量已经超过一些成熟乔木种类的林地的生产量,且荆条灌丛中生长最快的群落(样地3)的地上部生产量已接近一些乔木种类的幼龄林地的生产量说明荆条灌丛有较高的生长速度。 生物量累积比作为植物或群落衰老程度的指标,说明荆条灌丛较之其它原生灌丛还是较”年轻”的,样地1的生物量累积比较大,是该群落遭受频繁砍伐的反映。 由荆条灌丛立地的潜在生产量的分析可知样地1的荆条灌丛离其”成熟类型”的生产量还差距很大,而样地3的生产量正接近其”成熟类型”。结合前面的分析,可以推测在人类活动频繁和强度的干扰下,样地l的荆条灌丛没有继续向其成熟类型发育,而在中途衰退了。 西山荆条灌丛中,在代谢活动较旺盛的部位,N和K的含量较高,Hg,P和Zn也表现相似的倾向,A1和Fe则表现了相反的趋势,即代谢活动较强的部位,含量较低。Mn,CaHa是介于中问的一种类型。比较各组分中元素的含量值,Mg是较均匀的类型,其余元素在不同组分间含量的差异都较悬殊。西山荆条灌丛中,Mn,Mn, Mg,CaAI五个元素都以土壤中的含量为最高,N的含量则以上壤为最低,而植物组分中 K的含量一直保持较高的水平。 多数元素在荆条根球中的含量最低,包括Fe,Hn,Zn,(CaP和AI。随着年龄的增大,各组分中K的含量有增加的趋势(其增加量大于其它元素的增加量),在西山荆条灌从中,植物组分以及及土壤里各元素除p外,其含量均与两个以上元素的含量呈显著相关性(图11).而P的含量只与N的含量具极显著相关性,,在植物组分中,灰分含量与Fe,Mn,CaP,AI的含量均具极显著的相关性。荆条内部各组分的元寨岔登之间全部晕缀显著相关,而绝大部分植物组分中元素含量与土壤中相应元素的含量值无相关性。 植物组分中,其它植物地上部,其它植物地下部和羽叶是元素积累量最大的三个组分。荆枝中的CaHa荆根球和荆根中的Zn和Mg以及荆根中的Al,它们的含量与其积累量之间具有较明显的补偿现象,即它们的积累量并不随生物量的增减而发生显著的变化。 西山荆条灌丛中荆条和其它植物对10种元素的吸收总量基本相等。在荆条的总吸收量中,K,N,Ca吸收量占88.5%,其余7种元素的吸收量只占11.5%。在其它植物中,则以CaN和Al的吸收量占多数,达73.9%。在荆条和其它植物中,K和Al的吸收可能存在着拮抗关系。 西山荆条灌丛中荆条对K的吸收量最大,但对Mn的利用系数最大。10种元素中最大和最小吸收量之间在荆条中相差339倍(K和Zn之间),但荆条对各元素的利用系数却相差不多,平均为0.775±0.09。其它植物对10种元素的利用系数较荆条稍高,平均为0.826±0.07,整个西山荆条灌丛群落对元素的利用系数以Mn为最高,Na最低。 若以土壤中元素的垒量的贮量计算,荆条对N的吸收系数最大,Al最小。若以土壤中元素的有效含量(可溶性或可代换性量)汁,则荆条的吸收系数以Al最大,Ca小 (表21)。土壤元素(全量)的周转时间,Al最长,达2603.2年,多数元素在450-600年 之间,只有N,P,K三个元素的周转时间最短,分别只有35.4,151.9,和109.l年。 西山荆条灌丛中荆条以凋落物形式归还土壤的元素量在其吸收量中所占的比例(归 还率),Zn (26.5%),Mg (36.1%),Ca (36.1%),P(21.3%)和N(25.0%)属较高的类型, Al (13.5%),Na14.6%)和K(13.1%)居中,Mn (8.5%)和Fe(8.0%)最低。灌丛群落中 元素的归还率除Mn最小(12.1%)外,其余在21.3%-37.9%之间。 西山荆条灌丛中,荆条和其它植物所吸收的元素量在群落总吸收量中所占的比例, 各元素之间显著不同,均匀的类型有N,Zn,Mg和Na即荆条和其它植物的吸收量相当。 K是唯一以荆条的吸收量占优势的元素,荆条吸收的K占群落总吸收量的80.7%。其余 元素,Mn,P,Al,Fe和Ca是其它植物的吸收量显著大于荆条的吸收量(表22,图45)。 荆条所吸收的无素量,在其内部各组分中的分配(存留)格局,普遍规律是将绝大 部分用于其叶片的生长(或存留于叶片)中.Mn是唯一例外的元素,荆条将其吸收量的 最大部分存留于其枝条中。其余9个元素.荆条对其叶片存留后剩下的那部分元素量的 分配方式可以区分出三种类型:将剩余部分中的多数存留于其枝条的元素有AI,Fe,Zn, Mg;将剩余部分中的多数存留于其地下部的元素有P,Na 和Ca;而K和N则属于中间 的类型,即用于叶片后的剩余的K和N在荆枝和荆条地下部(根球和艉)中较均匀的分配 (表22,图46). 西山荆条灌丛中元素循环的强度和速度都显著大于汤河口荆条灌丛,两个样地的元 素循环特征的最显著差异是汤河口荆条灌丛中荆条将其吸收的元素量中的最大部分存留 于其地下部,和西山样地完全相反,这可能是两个样地荆条灌丛元素循环特征的最本质 的区别。其原因,可能是汤河口样地中荆条对其地上部遭受频繁砍伐的一种适应方式, 也可能是汤河口荆条滋丛衰老的反映。 西山灌丛中荆条落叶分解过程中其失重率曲线呈双S形,其失重率最大增长速度出现在第166-299天之间。经过539天的分解作用,荆条枯落叶损失了其于重的53.3%,其中分解期(千重损失50%所用时间)为514.1天。 与干重失重率相对应,荆条枯落叶的平均腐解率的最高值出现在299和364天,而区 间腐解率的最大值则出现在第66—227天和第227 - 299天之间,比平均腐解率的最高值 出现的早,这与其总失重率曲线是非常吻合的,因为第166 - 227天及第227 - 299天之间 的高腐解率导致了其后高失重率的出现。 平均腐解率与平均气温之间具显著相关性(P<0.0S),而与平均降水量只在90%置信区间内有相关性,区间腐解率也只在90%置信区内与平均气温有相关性。 以平均腐解率计算,荆条枯落叶干重的95%被分解所需的时间为6.37年,比同一地区的侧柏、元宝槭、黄栌、山杏、刺槐,油讼和栓皮栎短,说明荆条叶片枯落物的分解速率是较快的。 荆条枯落叶分解过程中的失重主要由于有机物被分解引起的,且有机C可溶性糖 和粗纤维的分解决定了失重率变化的总趋势。 各有机物含量程分解过程中的变化各不相同。就浓度而言,以可溶性糖的浓度降低 速度最快,丹宁的浓度也显著的下降,粗脂肪和有机C度属于平缓下降的类型,而木 质素和粗纤维属另一极端的类型,其浓度持续升高。各有机物在枯落叶中的总量以不同 的速率减少。经过539天的分解作用,各有机物的损失率大小的顺序为可溶性糖(97.90%)>丹宁(95. 92%)>粗脂肪(70.83%)>有机C(61.59%)>粗纤维(37.36%)>木质素( 31,97%)。此外,不同的有机物的含量以不同的规律变化,其中可溶性糖和木质素在第105天内即被大量的分解而损失(分别损失63.66%和19.67%)。丹宁和有机C损失率的变化是较际准的S形曲线,粗纤维的损失率变化曲线为右抛物线的上半部,而粗脂肪类似S形曲线,但最不规则. 荆条枯落叶分解过程中矿质元素浓度和含董的变化很不规则。灰分含量作为大部分矿质元素含量的总和,其浓度在分解过程中稳定升高,而其总量则持续下降,所研究的10种矿质元素的浓度和总量的变化很不一致,在浓度变化方面,K是星下降趋势的唯一元素,其余元素(包括N,CaNaMg,P,Fe,Zn,Mn和Al)的浓度均随分解过程呈升高的趋势。从元素的总量方面可以区别出两种类型:即N,CaNaK,P5个元素属于减少的类型,而Fe,Mn,Zn,Mg和Al的总量则有所增加。 西山和汤河口两个样地的荆条灌丛都是渐近稳定的,且离其稳定态尚有一定距离,相对稳定性指数没有显示两个样地的稳定性具有显著的差异。 西山荆条灌丛的演替度大于汤河口灌丛,这和它们所受的人为干扰的强度的差异有紧密联系。
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浮游动物在海洋生态系统物质循环和能量流动中起着至关重要的作用。浮游动物物种组成、生物量和次级生产力的变化会改变生态系统的结构和功能。在黄海生态系统中如何描述这个过程,并使它易于模拟是本论文的研究目的。生物量和生产力是海洋生态系统食物网的基础。谁是浮游动物生物量和次级生产力的基础?哪些种类在生态系统中起关键作用?这些问题在黄海这样的温带陆架边缘海区很难回答,原因是物种组成、生物量和生产力的季节变化显著。因此,在对黄海食物产出的关键过程进行模拟时,需要应用既准确又简便的方法来对浮游动物群落的生态过程进行模拟。在对黄海浮游动物群落结构和物理海洋学特征进行充分的分析之后,浮游动物功能群的方法被确定用来进行黄海生态系统结构和功能的模拟。 根据浮游动物的粒径、摄食习性和营养功能,黄海浮游动物被分为6个功能群:大型浮游甲壳动物功能群(Giant crustacean,GC、大型桡足类功能群(Large copepods, LC、小型桡足类功能群(Small copepods,SC、毛颚类功能群(Chaetognaths)、水母类功能群(Medusae)和海樽类功能群(Salps)。GCLCSC按照粒径大小而划分的功能群,他们是高营养层次的主要食物资源。毛颚类和水母类是两类胶质性的肉食性浮游动物功能群,他们与高营养层次竞争摄食饵料浮游动物;海樽类与其他浮游动物种类竞争摄食浮游植物,而本身的物质和能量却不能有效的传递到高营养层次。本文研究报道了浮游动物各功能群的时空分布、基于浮游动物动能群的黄海生态区划分、饵料浮游动物功能群的生产力、毛颚类对浮游动物的摄食压力以及中华哲水蚤(Calanus sinicus)的摄食生态学。 春季,浮游动物生物量为2.1 g m–2,GCLCSC生物量的贡献率分别为19, 44 和 26%。高生物量的LCSC能群主要分布于山东半岛南岸的近岸海域,而GC要分布在远岸站位。夏季,浮游动物的生物量为3.1 g m–2,GC献了73%。GCLCSC要分布在黄海的中部海域。秋季,浮游动物生物量为1.8 g m–2,GCLCSC贡献率相似,分别为36, 33和23%,高生物量的GCLC布在黄海中部,而SC要分布在远岸站位。GCLC冬季浮游动物生物量(2.9 g m–2)的优势功能群,分别贡献率了57%和27%,高生物量的GCLCSC分布在黄海的中部海域。与GCLCSC比,毛颚类生物量较低,主要分布于黄海的中北部海域。水母类(本文中指小型水母类)和海樽类斑块分布明显,主要分布于黄海沿岸和北部海域。属于不同功能群的约10个种类为浮游动物的优势种,控制着浮游动物群落的动态。 春季,黄海可以被分成4个浮游动物生态区,浮游动物生物量的分布中心位于山东半岛南岸近岸海域,与第一个生态区相对应,LCSC分布中心起主要的控制作用;夏、秋和冬季,黄海分别被分成3、4和3个生态区,浮游动物生物量的分布中心均位于黄海的中部海域,均与各季节的第一个生态区相对应,GCLC分布中心生态区的优势功能群,对分布中心起主要的控制作用。黄海冷水团(YSCBW)在GCLCSC空间分布模式中起着重要的作用。黄海不同季节浮游动物生态区的空间分布模式及生态区中起控制作用的优势功能群类别有着重要的生态学意义。 我们将饵料浮游动物功能群细化为0.16–0.25 mm、0.25–0.5 mm、0.5–1 mm、1–2 mm和 >2 mm5个粒径组。应用生物能量学的方法研究了不同粒径浮游动物的生产力。结果表明:浮游动物次级生产力5月份最高,为91.9 mg C m–2 d–1,其次是6月和9月,分别为75.6 mg C m–2 d–1和65.5 mg C m–2 d–1,8月、3月和12月较低,仅为42.3 mg C m–2 d–1、35.9 mg C m–2 d–1和27.9 mg C m–2 d–1。根据这些结果,黄海浮游动物年次级生产力为18.9 g C m–2 year–1。0.16–0.25 mm和 0.25–0.5 mm 两个粒径组对浮游动物次级生产力的贡献率为58–79%,即相对应的SC能群的周转率(P/B, 0.091–0.193 d–1)要高于GCLC 黄海毛颚类功能群的优势种类为强壮箭虫(Sagitta crassa、纳嘎箭虫(S. nagae)、肥胖箭虫(S. enflata和百陶箭虫(S. bedoti)。我们对这四种箭虫的生产力和对浮游动物生物量和生产力的摄食压力进行了研究。结果表明:黄海毛颚类总的生物量为98–217 mg m–2,总的生产力为1.22–2.36 mg C m–2 d–1。黄海毛颚类的生物量占浮游动物总生物量的6.35–14.47%,而生产力仅占浮游动物总生产力的2.54–6.04%。强壮箭虫和纳嘎箭虫是黄海毛颚类功能群的绝对优势种,控制着黄海毛颚类群落的动态。黄海毛颚类总的摄食率为4.24–8.18 mg C m–2d–1,对浮游动物现存量和生产力总的摄食压力分别为为0.94%和12.56%。黄海冬季,浮游动物的现存量和生产力为0.4 g C m–2和0.026 g C m–2d–1,而毛颚类的摄食压力却达到了全年的最大值,为1.4%和20.94%。因此,毛颚类的摄食可能对冬季浮游动物群落结构造成重要的影响。通过不同体长组箭虫的摄食率可以推断,黄海毛颚类全年主要摄食小型桡足类,对SC能群的摄食压力最大。但是在夏季黄海冷水团形成的月份,毛颚类对前体长为2 mm的LC能群中的种类摄食压力也较大,但此时,由于优势种中华哲水蚤进入滞育阶段,因此毛颚类的摄食会对其种群数量造成严重的影响。 中华哲水蚤在春、秋季的摄食率分别为2.08–11.46和0.26–3.70 µg C female–1 day–1,与微型浮游生物的现存量呈显著的正相关。春季,在黄海的北部,中华哲水蚤通过摄食微型浮游生物吸收的碳量能够满足其代谢和繁殖需求,而在黄海的南部和秋季黄海冷水团锋区附近,中华哲水蚤必须通过摄食其他类型的食物资源来维持其代谢和生殖需求。较低的摄食率、无产卵以及种群中CV桡足幼体占优势表明,秋季中华哲水蚤在黄海冷水团区域内处于滞育状态。中华哲水蚤优先摄食微型原生动物,并且春季中华哲水蚤总的生长效率(GGE, 3–39%)与食物中微型原生动物的比例呈显著的正相关,表明微型原生动物具有较高的营养价值。但是,因较低的产卵率(0.16–12.6 eggs female–1 day–1)而导致的中华哲水蚤较低的总生长效率(13.4%),可能就是由于其食物中的必需营养成分含量不足(或缺乏)造成的。 本文从生物量的角度,对黄海浮游动物各功能群的时空分布、生态区划分进行了研究报道,对GCLCSC能群的生产力、毛颚类对浮游动物的摄食压力和中华哲水蚤的摄食生态学进行了较为深入的研究,这些结果为黄海食物产出的关键过程的模拟提供了基础资料。今后的研究重点应搞清楚黄海水母类对浮游动物次级生产力的摄食压力和海樽类在食物产出模型中产生的负效应的程度,浮游动物各功能群的组成、季节变化和空间分布模式的长期变化,尤其是在气候变化和人类活动的影响下,将是今后研究的重点。
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The new Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2011 document recommends a combined assessment of chronic obstructive pulmonary disease (COPD) based on current symptoms and future risk.
A large database of primary-care COPD patients across the UK was used to determine COPD distribution and characteristics according to the new GOLD classification. 80 general practices provided patients with a Read code diagnosis of COPD. Electronic and hand searches of patient medical records were undertaken, optimising data capture.
Data for 9219 COPD patients were collected. For the 6283 patients with both forced expiratory volume in 1 s (FEV1) and modified Medical Research Council scores (mean¡SD age 69.2¡10.6 years, body mass index 27.3¡6.2 kg?m-2), GOLD 2011 group distributions were: A (low risk and fewer symptoms) 36.1%, B (low risk and more symptoms) 19.1%, C (high risk and fewer symptoms) 19.6% and D (high risk and more symptoms) 25.3%. This is in contrast with GOLD 2007 stage classification: I (mild) 17.1%, II (moderate) 52.2%, III (severe) 25.5% and IV (very severe) 5.2%. 20% of patients with FEV1 o50% predicted had more than two exacerbations in the previous 12 months. 70% of patients with FEV1 ,50% pred had fewer than two exacerbations in the previous 12 months.
This database, representative of UK primary-care COPD patients, identified greater proportions of patients in the mildest and most severe categories upon comparing 2011 versus 2007 GOLD classifications. Discordance between airflow limitation severity and exacerbation risk was observed.
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Establecer la prevalencia de síntomas osteomusculares en el personal operativo de la empresa Emermédica S.A. durante los últimos 3 meses. Se realizó un estudio de corte trasversal en la empresa Emermédica S.A. de Bogotá en el ao 2012, tomando una muestra de 75 trabajadores entre médicos, enfermeros y conductores del área operativa, a los cuales se les aplicó un instrumento de morbilidad sentida basada en el Cuestionario Nórdico y la Encuesta Europea, en búsqueda de síntomas osteomusculares asociados a la actividad desempeñada y a factores como edad, género, horas de trabajo por turno, tipo de vehículo, actividad deportiva, equipos utilizados y posturas adoptadas durante el desarrollo de sus actividades. Para el análisis de la información se creó una base de datos a partir de los cuestionarios contestados válidos y se utilizó el programa estadístico SPSS.