713 resultados para N10


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Digital image

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Ancien possesseur : Argenson, Antoine-René de Voyer (1722-1787 ; marquis de Paulmy d')

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The orphan nuclear receptor Nur77/N10 has recently been demonstrated to be involved in apoptosis of T cell hybridomas. We report here that chronic expression of Nur77/N10 in thymocytes of transgenic mice results in a dramatic reduction of CD4+CD8+ double-positive as well as CD4+CD8- and CD4-CD8+ single-positive cell populations due to an early onset of apoptosis. CD4-CD8- double-negative and CD25+ precursor cells, however, are unaffected. Moreover, nur77/N10-transgenic thymocytes show increased expression of Fas ligand (FasL), while the levels of the Fas receptor (Fas) are not increased. The mouse spontaneous mutant gld (generalized lymphoproliferative disease) carries a point mutation in the extracellular domain of the FasL gene that abolishes the ability of FasL to bind to Fas. Thymuses from nur77/N10-transgenic mice on a gld/gld background have increased cellularity and an almost normal profile of thymocyte subpopulations. Our results demonstrate that one pathway of apoptosis triggered by Nur77/N10 in double-positive thymocytes occurs through the upregulation of FasL expression resulting in increased signaling through Fas.

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Installée dans la rade de Boulogne-sur-Mer et inaugurée le 25 novembre 2004, la station MAREL Carnot mesure toutes les 20 minutes la salinité, la température de l’eau et de l’air, la fluorescence, la turbidité, la concentration en oxygène dissous, le pourcentage de saturation en oxygène, le P.A.R., l’humidité relative, la direction et la vitesse du vent, la hauteur d’eau et toutes les 12 heures, la concentration en nitrate, en phosphate et en silicium. Ce rapport vise à présenter les principaux éléments utiles à l’utilisateur des données afin de pouvoir adapter son étude en fonction de la disponibilité des données, de leur qualité et bien entendu de son objectif. Les résultats des paramètres fluorescence, turbidité, concentration en oxygène, température de l’eau sont présentés de manière plus détaillée afin de mettre en évidence les cycles saisonniers caractéristiques, la variabilité inter-annuelle et les éventuelles tendances.

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Purpose: To compare subjective blur limits for cylinder and defocus. ---------- Method: Blur was induced with a deformable, adaptive-optics mirror when either the subjects’ own astigmatisms were corrected or when both astigmatisms and higher-order aberrations were corrected. Subjects were cyclopleged and had 5 mm artificial pupils. Black letter targets (0.1, 0.35 and 0.6 logMAR) were presented on white backgrounds. Results: For ten subjects, blur limits were approximately 50% greater for cylinder than for defocus (in diopters). While there were considerable effects of axis for individuals, overall this was not strong, with the 0° (or 180°) axis having about 20% greater limits than oblique axes. In a second experiment with text (equivalent in angle to N10 print at 40 cm distance), cylinder blur limits for 6 subjects were approximately 30% greater than those for defocus; this percentage was slightly smaller than for the three letters. Blur limits of the text were intermediate between those of 0.35 logMAR and 0.6 logMAR letters. Extensive blur limit measurements for one subject with single letters did not show expected interactions between target detail orientation and cylinder axis. ---------- Conclusion: Subjective blur limits for cylinder are 30%-50% greater than those for defocus, with the overall influence of cylinder axis being 20%.

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Mammals vary dramatically in lifespan, by at least two-orders of magnitude, but the molecular basis for this difference remains largely unknown. The bowhead whale Balaena mysticetus is the longest-lived mammal known, with an estimated maximal lifespan in excess of two hundred years. It is also one of the two largest animals and the most cold-adapted baleen whale species. Here, we report the first genome-wide gene expression analyses of the bowhead whale, based on the de novo assembly of its transcriptome. Bowhead whale or cetacean-specific changes in gene expression were identified in the liver, kidney and heart, and complemented with analyses of positively selected genes. Changes associated with altered insulin signaling and other gene expression patterns could help explain the remarkable longevity of bowhead whales as well as their adaptation to a lipid-rich diet. The data also reveal parallels in candidate longevity adaptations of the bowhead whale, naked mole rat and Brandt's bat. The bowhead whale transcriptome is a valuable resource for the study of this remarkable animal, including the evolution of longevity and its important correlates such as resistance to cancer and other diseases.

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Malignant astrocytoma includes anaplastic astrocytoma (grade III) and glioblastoma (grade IV). Among them, glioblastoma is the most common primary brain tumor with dismal responses to all therapeutic modalities. We performed a large-scale, genome-wide microRNA (miRNA) (n=756) expression profiling of 26 glioblastoma, 13 anaplastic astrocytoma and 7 normal brain samples with an aim to find deregulated miRNA in malignant astrocytoma. We identified several differentially regulated miRNAs between these groups, which could differentiate glioma grades and normal brain as recognized by PCA. More importantly, we identified a most discriminatory 23-miRNA expression signature, by using PAM, which precisely distinguished glioblastoma from anaplastic astrocytoma with an accuracy of 95%. The differential expression pattern of nine miRNAs was further validated by real-time RT-PCR on an independent set of malignant astrocytomas (n-72) and normal samples (n=7). Inhibition of two glioblastoma-upregulated miRNAs (miR-21 and miR-23a) and exogenous overexpression of two glioblastoma-downregulated miRNAs (miR-218 and miR-219-5p) resulted in reduced soft agar colony formation but showed varying effects on cell proliferation and chemosensitivity. Thus we have identified the miRNA expression signature for malignant astrocytoma, in particular glioblastoma, and showed the miRNA involvement and their importance in astrocytoma development. Modern Pathology (2010) 23, 1404-1417; doi:10.1038/modpathol.2010.135; published online 13 August 2010

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In bacteria, alternate mechanisms are known to synthesize N-10-formyltetrahydrofolate (N10-formyl-THF) and formyl glycinamide ribotide (fGAR), which are important in purine biosynthesis. In one of the mechanisms, a direct transfer of one carbon unit from formate allows Fhs to convert tetrahydrofolate to N-10-formyl-THF, and PurT to convert glycinamide ribotide (GAR) to fGAR. Our bioinformatics analysis of fhs and purT genes (encoding Fhs and PurT) showed that in a majority of bacteria (similar to 94%), their presence was mutually exclusive. A large number of organisms possessing fhs lacked purT and vice versa. The phenomenon is so penetrating that even within a genus (Bacillus) if a species possessed fhs it lacked purT and vice versa. To investigate physiological importance of this phenomenon, we used Escherichia coli, which naturally lacks fhs (and possesses purT) as model. We generated strains, which possessed fhs and purT genes in singles or together. Deletion of purT from E. coli in the presence or absence of fhs did not confer a detectable growth disadvantage in pure cultures. However, growth competition assays revealed that the strains possessing either of the single genes outcompeted those possessing both the genes suggesting that mutual exclusion of purT and fhs in organisms confers fitness advantage in mixed cultures.

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El presente compendio ha sido elaborado como texto básico para la asignatura EQUIPOS E INSTALACIONES PECUARIAS que se imparte en el séptimo semestre de la carrera ingeniería en Zootecnia, el cual pretende ser un auxiliar de consulta y autoestudio. Este trabajo está dedicado a exponer, en primera instancia los principios, la importancia y las atenciones previos a la consideración y el diseño de los alojamientos e instalaciones ganaderas. En Nicaragua una de las principales dificultades es la inadecuación de los alojamientos e instalaciones por falta de un análisis, de un estudio profesional y serio, de las necesidades reales de la crianza de animales domésticos1 en lo que a estos conceptos se refiere teniendo en cuenta la especie que se pretende explotar, dentro de ella el tipo de animal que se va a criar, el sistema de explotación que se pretende desarrollar y el conjunto de técnicas de producción que se desea aplicar. De forma expositiva se aborda los alojamientos e instalaciones bovinas, porcinas, ovicaprinas, avícolas, equinas y cunícolas. Debe quedar claro, que el presente compendio únicamente intenta ser una exposición introductoria al complejo tema que se aborda aquí. Por eso, estimados estudiantes es mi propósito contribuir en vuestra formación, con los temas desarrollados a continuación, y asesorarlos con técnicas correctas para el buen desarrollo de la ganadería en Nicaragua.

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En el presente trabajo se presenta una propuesta para la elaboración de un prototipo de silo prensa de palanca manual para ser utilizado para el proceso de ensilaje de forraje, el cual partió de un modelo comercial que se encuentra en el mercado internacional. Se plantearon las modificaciones que se realizarían al modelo para obtener un prototipo. Se describió el diseño de máquina y su construcción, además se realizaron pruebas de funcionamiento al prototipo, se utilizó pasto cubano CT-115 (P. purpureum x P. thyphoides), el material fue picado y compactado con el prototipo para la elaboración de ensilaje. Se describen las pruebas realizadas para determinar el tamaño y diámetro de silo obtenidos (82.2 cm x 83 cm) y el tiempo (36.2 min a 20 min) que le tomaría a un operario o dos elaborar una silo bolsa. Se obtuvo el peso promedio de los silos elaborados (100.2 kg). Para medir la eficiencia de la máquina se comparó su funcionamiento con un silo barril tradicional obteniendo un rendimiento de 0.3 ton h-1, contra un 0.14 ton h-1 respectivamente. El costo de elaboración de la máquina fue de $ 289.66, sin embargo este costo puede variar por que la máquina es de fácil construcción y puede ser elaborada por el mismo productor y con materiales no utilizados que se pueden encontrar en la finca

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A diagnostic survey of the incidence of mayfly (Povilla sp.) infestation of wooden infrastructures of the artisanal fishers in ten (10) lagoons and marine fishing villages of Ogun States (Nigeria) was carried out through the application of structured questionnaire and participatory Rural Appraisal interviews. The demographic, infrastructural and socioeconomic characteristics of the ten fishing villages sampled were derived and analyzed. The infestation which occurs all year round is found to be most prevalent (70%) in the wet season, increasing proportionally with salinity from 56% (brackish water); to 63% (marine water). The life-span of Povilla sp. is reduced from 55% to 62% (freshwater); 41% (brackish water) and 38% (marine water). Annual financial loss of N10,000.00 per fisher or N80,000,000.00 to the 8000 artisanal fishers affected in Ogun State is discussed. It is recommended that fishers should preferably use non-wood crafts and infrastructures while adopting appropriate management strategies for containing the existing infestation

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The study focused on men and women involved in artisanal fisheries in some selected areas of Ikorodu Local government in Lagos State. The random sampling technique was used to select 50 fishermen each at Ibeshe and Baiyeku sites. The results revealed that majority of the fishermen were male, christian, semi-illiterate, and married. Data were collected on capital sources, labour used, income, gear techniques and type of fish caught. Analysis showed that the highest sources of capital were from personal savings (50%). Majority of labour used were hired labour, 44% at Ibeshe and 50% at Baiyeku. Highest monthly income ranged between N10, 000 - N25, 000 at both sites. Planks were mostly used at both sites for fishing boats as well as means of transport (Ibeshe 68%, Baiyeku 72%). Common fishing gear was the gill net, The fishes caught were found to be of various tyupes. Ethalmalosa fimbriata constituted the highest fish species caught by weight and number at both sites (50%). However, the problems of capital source were most peculiar coupled with high cost of fishing materials and labour scarcity

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  氮素作为陆地生态系统生产力主要的限制因子,对生态系统过程的调控有着重要的意义。净氮矿化是有机氮素到无机氮素的转变过程,该过程决定了土壤氮素的可利用性。准确估计土壤的供氮能力可以为确定最佳施肥量和施肥时间提供理论依据,并将影响着土地的可持续发展和管理政策。氮矿化潜力N0被定义为在最适温度和湿度下,土壤氮素在无限时间内所能矿化的最大量。由于氮矿化潜力是土壤供氮能力很好的指示值,所以对氮矿化潜力的研究能够使我们更好地了解土壤的氮素矿化动态和其供氮潜力。   为更好地了解天然草原氮素矿化对全球氮沉降背景以及草原施肥管理模式的响应,我们从2000年起在内蒙古羊草草原开展了长期的氮素添加实验,分别设置对照(N0)、添加5g N•m-2(N1.75)、30g N•m-2(N10.5)和80g N•m-2(N28)四个氮肥添加梯度以及对照(control)、添加100g有机肥•m-2(O100)、添加500g有机肥•m-2(O500)、添加1000g有机肥•m-2(O1000)四个有机肥添加梯度。氮肥添加在相邻并同时进行施肥的两个生态系统类型中展开,即成熟羊草草原(A区,1979年围封)和退化的羊草草原(B区,1999年围封),有机肥添加也同时在与之相邻的C区中展开(C区的土地利用历史与B区一致)。 2002年和2006年,从A、B区中进行氮肥处理后的土壤取样;有机肥处理的土壤样品从2002年C区中获得。土样在最佳温度(25℃)和湿度(60%田间持水量(WHC))下进行了5周室内培养,并用阶段淋溶方法来测定氮肥添加和有机肥添加对土壤氮矿化动态的影响。   氮肥添加显著降低了土壤的pH值,但累积氮矿化量与土壤pH值、有机碳、全氮均没有显著的相关性。在两个区内,氮素添加都显著改变了土壤的累积氮矿化量。最高氮素处理N28相对应于最低的累积氮矿化量,而低氮素处理N1.75却使得累积氮矿化量最高。同时,在N0和N1.75处理中硝态氮的含量高于铵态氮,但在N28处理中却表现出相反趋势。实验还表明大多数氮素添加强度处理在A区比B区有更高的土壤累积氮矿化量。   有机肥添加也显著改变了土壤5周内的累积氮矿化量,并且累积氮矿化量随有机肥添加强度的升高而显著增加。培养5周末时土壤的累积铵态氮的含量与有机肥施加强度之间并没有相关性,但是累积硝态氮的含量有随着有机肥施加强度的上升而增加的趋势。   基于前5周土壤培养所得到的结果,我们选择了氮肥添加的N0,N1.75, N28处理以及有机肥添加的control、O100、O1000处理继续进行了长达15周的培养。培养数据与描述土壤氮矿化动态的一级动力学模型--first-order kinetics: Nm=N0(1-exp(-kt))拟合良好( R2=0.893~0.97)。无论是氮肥添加还是有机肥添加都显著增加了土壤的氮矿化潜力N0,并且N0随着氮肥或者机肥添加强度的增加而增加。对于氮肥处理的土壤来说, N0与氮矿化速率常数k之间反向相关,但是在有机氮处理的土壤中N0与k之间却没有相关性。总的结果显示,经有机肥添加的土壤比经氮肥添加的土样有着更大的氮矿化潜力N0值以及氮矿化速率常数k值,较大的k值暗示着土壤氮素较快的周转速率。

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本论文以沈阳张士污灌区土壤为例,首次采用传统微生物生态学与现代微生物分子生态学相结合的研究方法系统地研究了污灌区长期重金属污染胁迫下原位农田土壤微生物特征。结果表明,虽然已经停止污灌十多年,张士灌区土壤耕作层(0~30 cm)仍然存在普遍的Cd污染,灌区土壤Cd含量高达1.75~3.89 mg kg-1。部分区域土壤Cd呈现向下迁移的趋势,且同时伴随有Cu、Zn复合污染。灌区土壤Cd含量较高时清水灌溉能降低土壤表层Cd含量,灌区土壤Cd含量下降到一定程度(约2 mg kg-1)后,清水灌溉对消除土壤表层Cd污染的作用消失。重金属元素中Cd对土壤微生物的影响最突出,在三个不同季节中土壤Cd与土壤微生物生物量(MBC)和微生物商(qM)呈显著负相关,与土壤微生物代谢商(qCO2)呈显著正相关。所检测的微生物指标中qM和qCO2与多种重金属元素呈显著相关性,可作为评价一定程度重金属污染的微生物指标。土壤营养元素(除P外)与微生物特征呈显著正相关性,土壤营养元素对微生物的刺激作用有可能在某种程度上掩盖了重金属对土壤微生物的负面影响。 用16S rDNA-PCR-DGGE方法,研究了不同浓度Cd胁迫下土壤Cd抗性细菌群落结构的动态变化,结果表明在Cd的胁迫下Cd抗性细菌多样性显著增加,不同土壤样品中Cd抗性细菌群落结构向相似的方向偏移,群落结构最终将可能趋向一致。Cd胁迫使敏感菌Pontibacter消失,而伯克氏菌(Burkholderia)、罗尔斯通氏菌(Ralstonia)、芽孢杆菌(Bacillus)和节杆菌(Arthrobacter)则富集成为优势菌。 从张士灌区Cd污染土壤中分离出32株Cd抗性细菌,研究了Cd抗性细菌和Cd抗性基因cadA的分布特征。这32株Cd抗性细菌分别归属于拟杆菌门(Bacteroidetes)(37.5%)、变形菌门(Proteobacteria) (37.5%)、放线菌门(Actinobacteria)(9.4%) 和厚壁菌门(Firmicutes)(15.6%)。在液体LB培养基中对Cd的抗性浓度都大于2 mmol L-1,对Zn抗性浓度介于5~13 mmol L-1。首次从Cetobacillus属的Cd抗性菌株S1基因组DNA中扩增出cadA基因的部分片断。在芽孢杆菌属(Bacillus)的4株菌N7,N9,N10和N11的基因组DNA中扩增出cadA基因的部分片断。序列分析结果表明这5株菌的cadA基因序列相似性为99%~93%,它们与坚强芽孢杆菌(Bacillus firmus) cadA 基因序列(M90750)相似性为94%~92%。系统发育分析结果表明这5株菌的cadA都与Bacillus firmus cadA 基因有着较近的亲缘关系。不同属的Cd抗性细菌间cadA基因的高度相似性揭示了cadA基因能在不同种属间转移的特性。