984 resultados para Martins, Nabur, d. ca. 1454.
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Yields, correlation shapes, and mean transverse momenta p(T) of charged particles associated with intermediate-to high-p(T) trigger particles (2.5 < p(T) < 10 GeV/c) in d + Au and Au + Au collisions at root s(NN) = 200 GeV are presented. For associated particles at higher p(T) greater than or similar to 2.5 GeV/c, narrow correlation peaks are seen in d + Au and Au + Au, indicating that the main production mechanism is jet fragmentation. At lower associated particle pT < 2 GeV/c, a large enhancement of the near- (Delta phi similar to 0) and away-side (Delta phi similar to pi) associated yields is found, together with a strong broadening of the away-side azimuthal distributions in Au + Au collisions compared to d + Au measurements, suggesting that other particle production mechanisms play a role. This is further supported by the observed significant softening of the away-side associated particle yield distribution at Delta phi similar to pi in central Au + Au collisions.
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Balance functions have been measured for charged-particle pairs, identified charged-pion pairs, and identified charged-kaon pairs in Au + Au, d + Au, and p + p collisions at root s(NN) = 200 GeV at the Relativistic Heavy Ion Collider using the STAR detector. These balance functions are presented in terms of relative pseudorapidity, Delta eta, relative rapidity, Delta y, relative azimuthal angle, Delta phi, and invariant relative momentum, q(inv). For charged-particle pairs, the width of the balance function in terms of Delta eta scales smoothly with the number of participating nucleons, while HIJING and UrQMD model calculations show no dependence on centrality or system size. For charged-particle and charged-pion pairs, the balance functions widths in terms of Delta eta and Delta y are narrower in central Au + Au collisions than in peripheral collisions. The width for central collisions is consistent with thermal blast-wave models where the balancing charges are highly correlated in coordinate space at breakup. This strong correlation might be explained by either delayed hadronization or limited diffusion during the reaction. Furthermore, the narrowing trend is consistent with the lower kinetic temperatures inherent to more central collisions. In contrast, the width of the balance function for charged-kaon pairs in terms of Delta y shows little centrality dependence, which may signal a different production mechanism for kaons. The widths of the balance functions for charged pions and kaons in terms of q(inv) narrow in central collisions compared to peripheral collisions, which may be driven by the change in the kinetic temperature.
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We report a measurement of high-p(T) inclusive pi(0), eta, and direct photon production in p + p and d + Au collisions at root s(NN) = 200 GeV at midrapidity (0 < eta < 1). Photons from the decay pi(0) -> gamma gamma were detected in the barrel electromagnetic calorimeter of the STAR experiment at the Relativistic Heavy Ion Collider. The eta -> gamma gamma decay was also observed and constituted the first eta measurement by STAR. The first direct photon cross-section measurement by STAR is also presented; the signal was extracted statistically by subtracting the pi(0), eta, and omega(782) decay background from the inclusive photon distribution observed in the calorimeter. The analysis is described in detail, and the results are found to be in good agreement with earlier measurements and with next-to-leading-order perturbative QCD calculations.
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Rare-earth and lead ions (Eu3+, Tb3+, Dy3+, Pb2+) doped Ca2Y8 (SiO4)(6)O-2 and Ca2Gd8(SiO4)(6)O-2 thin films have been dip- coated on silicon and quartz glass substrates through the sol- gel route. X- Ray diffraction (XRD), TG- DTA, scanning electron microscopy (SEM), atomic force microscopy (AFM), FT- IR and luminescence excitation and emission spectra as well as luminescence decays were used to characterize the resulting films. The results of XRD reveal that these films remain amorphous below 700 degreesC, begin to crystallize at 800 degreesC and crystallize completely around 1000 degreesC with an oxyapatite structure. The grain structure of the film can be seen clearly from SEM and AFM micrographs, where particles with various shapes and average size of 250 nm can be resolved. Eu3+ and Tb3+ show their characteristic red (D-5(0)-F-7(2)) and green (D-5(4) - F-7(5)) emission in the films with a quenching concentration of 10 and 6 mol% (of Y3+), respectively. The lifetime and emission intensity of Eu3+ increase with the temperature treatment from 700 to 1100 degreesC, while those of Tb3+ show a maximum at 800 degreesC. Energy transfer phenomena have been observed by activating the oxyapatite film host- lattice Ca2Gd8(SiO4)(6)O-2 with Tb3+ (Dy3+). In addition, Pb2+ can sensitize the Gd3+ sublattice in Ca2Gd8(SiO4)(6)O-2.
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海洋是驱动大气环流的主要“引擎”,海表温度(SST)又是揭示海洋环境变化的重要参数。利用有孔虫Mg/Ca值恢复SST具有较高精密度,是目前恢复SST较成功的方法之一。本论文旨在建立一套有效的有孔虫清洗方法和ICP-OES测试有孔虫Mg/Ca值的分析方法。 文中分析了53份西菲律宾海区(N18°40.23′,E135°37.11′;水深3225m)表层沉积物中浮游有孔虫Globigerinoides ruber(白色)Mg/Ca值。结合本研究区的特点,文中使用的清洗方法是有孔虫Mg/Ca值测试常用的“Mg”清洗方法,主要是由以下步骤构成:①用超纯水和甲醇在超声波水浴中清洗,②显微镜下剔除深色硅酸盐颗粒,③用氧化试剂去除有机质(加入30%H2O2和0.1M NaOH溶液在90℃左右的沸水浴中加热),④酸洗(250μl 0.001N HNO3 超声波水浴中清洗10S)。清洗干净的样品经超纯硝酸溶解成溶液后,利用电感耦合等离子体发射光谱(ICP-OES)对其进行Mg/Ca值的分析测试。仪器操作条件如下:辅助气流量(Ar)为0.5L/min(0.5L/min-1.5L/min),雾化器压力为0.2Mpa(0-0.4Mpa),泵速为20rpm(0-125rpm),高频输出功率(RF)为1150W(750W-1500W),火焰高度为15.5mm(8-21mm),通过多次重复测量一组Mg/Ca=3.333mmol/mol的标准溶液,其Mg/Ca期精密度<0.5%,长期精密度为1%。53份样品之间Mg/Ca值的RSD2.7%,利用Lea(2000)建立的太平洋地区浮游有孔虫G. ruber(白色)的Mg/CaSST的校正公式:Mg/Ca(mmol/mol) =0.30exp[0.089×SST(℃)],得到本研究区的SST为28℃±0.3℃。
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模拟高原低氧条件研究高原鼠兔肝细胞内质网(Endoplasmic reticulum , ER ) 和心肌肌浆网(Sarcoplasmic reticulum , SR) 钙泵功能变化。实验设对照组(海拔2 300 m ) 和两个低氧实验组(模拟海拔5 000m 和7 000m )。24 h 急性低氧时, 海拔5 000 m 组高原鼠兔ER 的Ca2+ 泵活性无变化, 海拔7 000 m 组高原鼠兔ER Ca2+泵活性下降29102%。7 d 亚急性低氧时高原鼠兔SR 的Ca2+泵活性无显著变化。高原鼠兔ER 的Ca2+泵活性在海拔5 000 m 组和7 000 m 组分别升高32.50% 和33.33%。25 d 慢性低氧时高原鼠兔ER , SR 的Ca2+ 泵活性均无显著变化.表明: 急性低氧对Ca2+泵功能有抑制作用, 低氧7 d 后抑制缓解, 至25 d 低氧时趋于恢复。
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本论文通过对贵州贵阳花溪杨中喀斯特山区的植被调查与土壤样品分析, 研究土壤-植被中CaMg、 K、P分布特征、变化规律及其影响因素,并在此基础上尝试Ca位素的预处理研究,以期为喀斯特地区土壤-植被中CaMg、 K、P(尤其是Ca的生物地球化学循环研究奠定基础,同时为植被演替、物质循环研究和退耕还林还草的人工恢复提供植物自身的营养依据。本次研究取得如下认识: 1.受石灰岩母岩控制,土壤样品元素含量的特征为:CaO>MgO>K2O> P2O5。同一元素沿海拔变化有一定的相关性,并且相关性随元素的不同存在差异:随海拔高度的增加CaO含量有升高的趋势,而MgO 、K2O、Na2O含量都有所降低。表层土壤中K2O-Na2O含量正相关变化,CaO-K2O含量负相关变化。并且从土壤表层到底层在剖面-1中随深度增加,CaO、MgO、K2O含量升高,而P2O5的含量则有上升的趋势。土壤中元素的上述分布特征主要与石灰岩的风化成土作用过程中不同分化程度土壤Ca淋失和来自高处的富钙雨水输入有关。 2.喀斯特生态环境富钙的这一特点对喀斯特灌丛植物的种类成分和营养元素含量有很大影响。地貌部位、海拔高度对植物CaMg 、K、P含量也有不同程度的影响。植物CaMg 、K、P含量由高到低依次为:Ca > K > Mg >P。苔藓与其它植物比较, CaMg、 K、P的含量都小于其它三类较高等的植物,这一现象与其自身的生物学特性有关:苔藓植物组织结构简单,不具备发达的输导组织,不具备真正的根系,不利于从土壤等基质中吸收营养。在、灌草、灌木、藤本三类植物营养元素之间Ca –P含量具有负相关变化,Mg –P含量具有正相关变化;在所分析的植物种,P- K含量变化呈正相关,并且植物叶片Ca/K比值随着P含量的增加而显著地以指数形式减小。这是因为植物体内的K和P对于Ca说起着平衡离子(counter ion)的作用。 3. 生境中基岩裸露和土体浅薄的特点,极大地制约了喀斯特灌丛的发育,喀斯特生境的富含钙的特点对喀斯特灌丛植物的种类成分和元素含量有很大的影响。但是杨中灌丛群落植物CaMg、K、P含量和对应土壤CaO、MgO、K2O和P2O5含量相关性不明显。植物CaMg、K、P元素虽主要来源于土壤,但因其含量受元素地球化学性质、植物种类、土壤元素对植物有效态的含量等因素的制约,而使植物元素含量和土壤元素的含量没有明显的相关性. 4.从Ca位素的预处理研究来看,离子交换分离法对去除样品中的杂质效果较好。在以后测定过程中,有利于增强离子流稳定性和强度, 提高测量精度和准确度,与沉淀法相比较,此法适宜作为钙同位素样品的前处理方法。 关键词: 喀斯特 石灰土-灌丛系统 CaMg、K、P含量分布 钙同位素 环境地球化学
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了解过去是认识现在和预测未来的基础。晚全新世是PAGES研究的目标时段之一。寻找和解译最近2000年连续、高分辨率自然记录是古气候研究的热点与难点。本项研究有针对性地选择程海、草海和青海湖开展湖泊沉积物环境记录的精细研究,结合14C、210Pb和137Cs定年,系统探讨了碳酸盐碳氧同位素、纤维素碳氧同位素、有机质碳同位素以及介形虫壳体Li/Ca值指标的古环境指示意义。 通过研究,本论文取得了如下成果和新的认识: 1. 建立了一套有效的四阶段湖泊沉积物有机质纤维素提取方法(5%NaOH碱洗、5%HCl酸洗、亚氯酸钠和冰醋酸混合溶液漂白以及17.5%NaOH碱洗),红外光谱鉴定提取物为纯的α-纤维素,表明该实验方法是可行的,为今后广泛开展湖泊沉积物纤维素稳定同位素研究打下了坚实基础。 2. 多指标综合辨识了程海和草海沉积物碳酸盐主要是自生碳酸盐。程海和草海沉积物有机质C/N比值结合有机质碳同位素结果表明两湖的有机质分别源于水生植物藻类和大型水草。程海和草海沉积物碳酸盐含量主要反映了湖区温度的变化。 3. 程海、草海沉积物碳酸盐与青海湖沉积物介形虫壳体氧同位素组成均反映了湖区降水/蒸发比。降水/蒸发比大的湿润期,碳酸盐δ18O值小;降水/蒸发比小的干旱期,碳酸盐δ18O值大。程海沉积物碳酸盐碳同位素组成影响因素复杂,除了受大气与湖水之间的CO2交换影响外,还受水生植物光合/吸收作用的影响;草海沉积物碳酸盐碳同位素组成更大的变化范围,反映了湖区水生植物光合/吸收作用的影响,其异常的正值可能指示了湖区细菌参与有机质碳同位素分馏过程。 4. 利用草海沉积物有机质纤维素氧同位素定量恢复了湖水氧同位素组成变化。在此基础上,结合碳酸盐氧同位素组成初步恢复了草海地区过去500年来温度变化历史:草海地区在过去500年明显存在四个冷期,包括1550-1610年,1670-1730年,1770-1870年和1890-1920年冷期,其中前三个发生在传统意义上的现代小冰期时段。与其它记录研究结果的一致性表明纤维素氧同位素结合碳酸盐氧同位素是恢复古温度变化的最有效途径之一,同时也为现代小冰期在中国西南地区的存在提供了湖泊沉积学方面的证据。 5. 不同类型水生植物湖泊,湖泊沉积物有机质δ13C值对湖泊初级生产力变化的响应过程不同。大型水草为主的湖泊(草海),其沉积物有机质δ13C值随湖泊生产力的增大呈现增加的变化趋势;藻类为主的湖泊(程海),其沉积物有机质δ13C随湖泊生产力的增大呈现减小的变化趋势,藻类易降解是导致δ13C值随湖泊生产力的增大呈现减小变化趋势的主要原因。 6. 程海沉积物碳酸盐和有机质碳同位素组成的正相关变化以及草海沉积物碳酸盐和有机质碳同位素组成的负相关变化.表明湖泊生产力变化并不是导致碳酸盐和有机质碳同位素正相关变化的主要原因,湖泊水生植物类型以及湖泊大小均起着重要作用。湖泊沉积物碳酸盐与有机质之间的碳同位素分馏(△δ13C)是一种有效的湖泊生产力指示剂,即使是在有微生物参与有机质碳同位素分馏过程的草海,△δ13C值也反映了湖泊生产力的变化过程。 7. 青海湖沉积物单一种属介形虫壳体胖真星介(Eucypris inflata)Li/Ca值与气象记录以及邻近地区都兰和祁连山树轮宽度指数恢复的古温度变化序列的对比研究揭示,介形虫壳体Li/Ca值与温度呈明显的负相关变化(Li/Ca值高,温度低;Li/Ca值低,温度高),表明介形虫壳体Li/Ca值是一种有效的古温度代用指标。 8. 青海湖沉积物单一种属介形虫壳体胖真星介(Eucypris inflata)Li/Ca值、氧同位素与反映太阳活动的大气14C含量和冰芯10Be含量的一致性变化表明青海湖地区温度和降雨量的同步变化主要受太阳活动控制。
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Publikacja (…) jest zbiorem tekstów poświęconych zagadnieniu autonomii w dydaktyce języków obcych. Teksty te – w obecnej postaci artykułów – stanowią zapis referatów wygłoszonych na konferencji poświęconej temu właśnie, niezwykle istotnemu dla nowoczesnej dydaktyki zagadnieniu. Konferencje tego typu nigdy dotąd w Polsce się nie odbywały. Jest to więc novum na naszym terenie i wielki tytuł do chwały dla uczelni, która podjęła się organizacji takiego wydarzenia i publikacji artykułów opracowanych na podstawie wygłoszonych tam referatów. Dlatego publikację uważam za niezwykle ważną i potrzebną. (z recenzji wydawniczej Prof. dr hab. Hanny Komorowskiej)
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Celem publikacji jest podjęcie próby przeanalizowania polityki, jaką Turcja prowadzi wobec obcokrajowców poszukujących schronienia na jej terytorium. O ważkości zagadnienia zadecydowała w ostatnich latach przede wszystkim tocząca się w Syrii wojna domowa, w wyniku której na terytorium Turcji znalazło się ponad 700 tysięcy Syryjczyków. Szczególne w tym kontekście kontrowersje budzi fakt stosowania przez Turcję podwójnych standardw w przedmiocie nadawania imigrantom konwencyjnego statusu uchodcy. Państwo to, jako jedno z czterech na świecie, w momencie przystępowania do Konwencji dotyczącej statusu uchodców i Protokołu nowojorskiego zastrzegło sobie prawo do stosowania w tej materii tzw. kryterium geograficznego. W efekcie, o ile status uchodcy nadany być może osobom przybywającym zza zachodnich granic Turcji, o tyle uciekinierzy z państw takich, jak Syria, Iran, czy Irak z formalnego punktu widzenia są „poszukującymi schronienia” (tur. sığınmacı). To zaś oznacza brak ich konwencyjnej ochrony. Celem artykułu jest jednak nie tylko przeanalizowanie prawnego i rzeczywistego położenia, w jakim znajdują się ofiary syryjskiej wojny domowej, przybywające na terytorium Turcji, a także próba przewidzenia scenariusza rozwoju tejże sytuacji. Celem uczynienia analizy możliwie najbardziej rzetelną, odwołano się zarówno do anglo, jak i tureckojęzycznych materiałów źródowych.
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The aim of the article is to outline the key issues surrounding legal notions of film authorship. For scholars interested in studying the process of production it is extremely important to analyze the status and scope of power of its participants as well as their position in the hierarchy – one of the main sources of priveleges is the fact of being recognized by the law as the author of the work produced. The article depicts the benefits of such situation, but its main aim is to descibe the legal rules of granting the status of the author. Outlined are the issues emerged from the two radically different legal system – european droit d`auteur tradition and american copyright. The first one honours the artists while the other focuses mostly on providing the certainty of the economics, so the actual authors of the work are not that important. The paper points to the fact that – especially in the case of american copyright – the actual (determined by law) situation of a creator may differ significantly from the character of their contribution to the process of producing a film. Analysis of the rules and principles of the law is essential to the understanding of the structural determinants of film production and deserves no less attention than social, political and economic factors.
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The genetics and biochemistry involved in the biodegradation of styrene and the production of polyhydroxyalkanoates in Pseudomonas putida CA-3 have been well characterised to date. Knowledge of the role played by global regulators in controlling these pathways currently represents a critical knowledge gap in this area. Here we report on our efforts to identify such regulators using mini-Tn5 transposon mutagenesis of the P. putida CA-3 genome. The library generated was subjected to phenotypic screening to identify mutants exhibiting a reduced sensitivity to the effects of carbon catabolite repression of aromatic pathway activity. Our efforts identified a clpX disrupted mutant which exhibited wild-type levels of growth on styrene but significantly reduced growth on phenylacetic acid. RT-PCR analysis of key PACoA catabolon genes necessary for phenylacetic acid metabolism, and SDS-PAGE protein profile analyses suggest that no direct alteration of PACoA pathway transcriptional or translational activity was involved. The influence of global regulators affecting the accumulation of PHAs in P. putida CA-3 was also studied. Phenotypic screening of the mini-Tn5 library revealed a gacS sensor kinase gene disruption resulting in the loss of PHA accumulation capacity in P. putida CA-3. Subsequent SDS-PAGE protein analyses of the wild type and gacS mutant strains identified post-transcriptional control of phaC1 synthase as a key point of control of PHA synthesis in P. putida CA-3. Disruption of the gacS gene in another PHA accumulating organism, P. putida S12, also demonstrated a reduction of PHA accumulation capacity. PHA accumulation was observed to be disrupted in the CA-3 gacS mutant under phosphorus limited growth conditions. Over-expression studies in both wild type CA-3 and gacS mutant demonstrated that rsmY over-expression in gacS disrupted P. putida CA-3 is insufficient to restore PHA accumulation in the cell however in wild type cells, over-expression of rsmY results in an altered PHA monomer compositions.
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p.317-323
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p.133-137