检索结果-南通市图书馆

On the non-evolution of the dependence of black hole masses on bolometric luminosities for QSOs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2012年第3期12卷 249-259页

作者： martín López-Corredoira Carlos m. Gutirrez Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna

There are extremely luminous quasi stellar objects （QSOs） at high redshift which are absent at low redshift. The lower luminosities at low redshifts can be understood as the external manifestation of either a lower Eddington ratio or a lower mass. To distinguish between both effects, we determine the possible dependence of masses and Eddington ratios of QSOs with a fixed luminosity as a function of redshifts; this avoids the malmquist bias or any other selection effect. For the masses and Eddington ratios derived for a sample of QSOs in the Sloan Digital Sky Survey, we model their evolution by a double linear fit separating the dependence on redshifts and luminosities. The validity of the fits and possible systematic effects were tested by the use of different estimators of masses or bolometric luminosities, and possible intergalactic extinction effects. The results do not show any significant evolution of black hole masses or Eddington ratios for equal luminosity QSOs. The black hole mass only depends on the bolometric luminosity without significant dependence on the redshift as （m BH/10 9 m ）≈ 3.4 （L bol/10 47 erg s-1）0.65 on average for z ≤ 5. This must not be confused with the possible evolution in the formation of black holes in QSOs. The variations of the environment might influence the formation of the black holes but not their subsequent accretion. It also leaves a question to be solved： Why are there not QSOs with very high mass at low redshift？ A brief discussion of the possible reasons for this is tentatively pointed out.

关键词： accretion—methods: statistical—quasars: general

Evaluation of glial cell proliferation with non-invasive molecular imaging methods after stroke

在线全文

学校读者我要写书评

暂无评论

neural Regeneration Research 2021年第11期16卷 2209-2210页

作者： Ana Joya Abraham martín Achucarro Basque Center for neuroscience LeioaSpain CIC biomaGUnE Basque Research and Technology Alliance(BRTA)PaseoSpain Ikerbasque Basque Foundation for Science BilbaoSpain

Glial proliferation:For the last decades,glial cells have been wrongly believed to have a mere passive supporting role for ***,this notion has clearly changed and it is now admitted that these cells are essential for the correct development and regulation of the nervous *** cell population are commonly subdivided in astrocytes,oligodendrocytes and *** the development,neural stem cells(nSCs)(called neuroepithelial progenitor cells or nPCs)transform into radial glia,the primary progenitor cells for neurons,astrocytes and oligodendrocytes(Zuchero and Barres,2015).microglial cells,however,derive from a mesenchymal precursor infiltration,meaning that during brain development,precursors generated in the bone narrow invade the nervous parenchyma and differentiate into microglial cells(Zuchero and Barres,2015).This proliferative capacity is preserved in the adult mammalian brain,and neurogenic nSCs are stored in two restricted regions of the central nervous system(CnS),the forebrain subventricular zone(SVZ)and the hippocampal dentate gyrus(subgranular zone).These cells continue to produce neurons and glial cells during the adulthood,being activated after certain signals and leaving the quiescent state(Urbán et al.,2019).This process,in which glial progenitor cells differentiate into mature glia during development and in the adult brain to maintain and regulate brain function,is called gliogenesis(Ardaya et al.,2020).

关键词： admitted maintain supporting

One-neutron stripping process in the^(209)Bi(^(6)Li,^(5)Li)^(210)Bi*reaction reaction

在线全文

学校读者我要写书评

暂无评论

nuclear Science and Techniques 2024年第6期35卷 120-129页

作者： Gao-Long Zhang Zhen-Wei Jiao Guang-Xin Zhang E.n.Cardozo B.Paes Shi-Peng Hu Jian-Qiang Qian Daniele mengoni Wei-Wei Qu Cong-Bo Li Yun Zheng Huan-Qiao Zhang Hui-Bin Sun nan Wang Chun-Lei Zhang J.J.Valiente-Dobón D.Testov m.mazzocco A.Gozzelino C.Parascandolo D.Pierroutsakou m.La Commara A.Goasduff D.Bazzacco D.R.napoli F.Galtarossa F.Recchia A.Illana S.Bakes I.Zanon S.Aydin Gde Angelis m.Siciliano R.menegazzo S.m.Lenzi S.Akkoyun L.F.Canto J.Lubian School of Physics Beihang UniversityBeijing 100191China Sino-French Institute of nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China Instituto de Física Universidade Federal Fluminense24210-340 NiteróiRio de JaneiroBrazil Laboratorio TAnDAR Comisión Nacional de Energía AtómicaBKNA1650 San MartíınArgentina Institute for Advanced Study in nuclear Energy and Safety Shenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Research and manufacture of High Purity Germanium materials and Fetectors Shenzhen UniversityShenzhen 518060China InFn Sezione di PadovaPaduaItaly Dipartimento di fisica Astronomia dell’Universita di padova PaduaItaly State Key Laboratory of Radiation medicine and Protection School of Radiation Medicine and ProtectionSoochow UniversitySuzhou 215123China China Institute of Atomic Energy Beijing 102413China The Key Laboratory of Beam Technology and material modification of ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Laboratori nazionali di Legnaro INFN35020 LegnaroItaly InFn Sezione di Napoli80126 NaplesItaly Dipartimento di Farmacia Universitàdi Napoli“Federico II”80131 NaplesItaly Department of natural and mathematical Sciences Faculty of EngineeringTarsus University33480 MersinTurkey Physics Division Argonne National LaboratoryLemontILUSA Department of Physics Sivas Cumhuriyet UniversitySivasTurkey Instituto de Física Universidade Federal do Rio de JaneiroRio de Janeiro CP 6852821941-972Brazil

One-neutron stripping process between^(6)Li and^(209)Bi was studied at 28,30,and 34 meV using the in-beamγ-ray spectroscopy ***γ-γcoincident analysis clearly identified twoγ-rays feeding the ground and long-lived isomeric states,which were employed to determine the cross *** one-neutron stripping cross sections were similar to the cross sections of complete fusion in the^(6)Li+^(209)Bi system,but the one-neutron stripping cross sections decreased more gradually at the sub-barrier region.A coupled-reaction-channel calculation was performed to study the detailed reaction mechanism of the one-neutron stripping process in^(6)*** calculations indicated that the first excited state of 5 Li is critical in the actual one-neutron transfer mechanism,and the valence proton of 209Bi can be excited to the low-lying excited state in(^(6)Li,^(5)Li)reaction,unlike in the(d,p)reaction.

关键词： Transfer reaction Weakly bound nuclei Cross section

Using lysosomal membrane stability of haemocytes in Ruditapes philippinarum as a biomarker of cellular stress to assess contamination by caffeine, ibuprofen, carbamazepine and novobiocin

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第7期25卷 1408-1418页

作者： Gabriela V. Aguirre-martínez Sara Buratti Elena Fabbri Angel T. DelValls m. Laura martín-Díaz Unitwin/Unesco/WiCoP Physical Chemistry Department University of Cdiz Faculty of Marine and Environmental SciencesPolígono Río San Pedro s/n 11510 Puerto Real Cdiz Spain Andalusian Center for marine Science and Technology (CACYTmAR) Campus Universitariode Puerto Real11510 Puerto Real Cdiz Spain University of Bologna Interdepartment Centre for Research in Environmental Sciences (CIRSA)via S. Alberto 16348123 Ravenna Italy

Although pharmaceuticals have beendetected in the environment only in the range from ng/L to μg/L, it has beendemonstrated that they can adversely affect the health status of aquatic organisms. Lysosomal membrane stability （LmS） has previously been applied as an indicator of cellularwell-being todetermine health status in bivalve mussels. The objective of this study is to evaluate LmS in Ruditapes philippinarum haemolymph using the neutral red retention assay （nRRA）. Clamswere exposed in laboratory conditions to caffeine （0.1, 5, 15, 50 μg/L）, ibuprofen （0.1, 5, 10, 50 μg/L）, carbamazepine and novobiocin （both at 0.1, 1, 10, 50 μg/L） for35days. Results show adose-dependent effect of the pharmaceuticals. The neutral red retention time measured at the end of the bioassaywas significantly reduced by 50% after exposure to environmental concentrations （p 〈 0.05）（caffeine = 15 μg/L; ibuprofen = 10 μg/L; carbamazepine = 1 μg/L and novobiocin = 1 μg/L）, compared to controls. Clams exposed to these pharmaceuticalswere considered to present adiminished health status （retention time 〈45 min）, significantlyworse than controls （96 min）（p 〈 0.05）. The predicted no environmental effect concentration （PnEC） results showed that these pharmaceuticals are very toxic at the environmental concentrations tested. measurement of the alteration of LmS has been found to be a sensitive technique that enables evaluation of the health status of clams after exposure to pharmaceuticals under laboratory conditions, thus representing a robust Tier-1 screening biomarker.

关键词： neutral red pharmaceuticals bioassay haemolymph bivalves health status manila clam

mobility of Arsenic and Heavy metals in a Sandy-Loam Textured and Carbonated Soil

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第2期19卷 166-175页

作者： I. GARC íA m. DIEZ F. mart ín m. SImón C. DORROnSORO Departamento Edafologia y Quimica Agricola CITE IIB Carretera Sacramento s/n 04120 University of Almeria (Spain) Departamento Edafologia y Quimica Agricola Campus Fuentenueva s/n 18002 University of Granada (Spain)

The continued effect of the pyrite-tailing oxidation on the mobility of arsenic, lead, zinc, cadmium, and copper was studied in a carbonated soil under natural conditions, with the experimental plot preserved with a layer of tailing covering the soil during three years. The experimental area is located in Southern Spain and was affected by a pyrite-mine spill. The climate in the area is typically mediterranean, which determines the rate of soil alteration and element mobility. The intense alteration processes that occurred in the soil during three years caused important changes in its morphology and a strong degradation of the main soil properties. In this period, lead concentrated in the first 5 mm of the soil, with concentrations higher than 1500 mg kg?1, mainly associated to the neoformation of plumbojarosite. Arsenic was partially leached from the first 5 mm and mainly concentrated between 5–10 mm in the soil, with maximum values of 1239 mg kg-1; the retention of arsenates was related to the neoformation of iron hydroxysulfates (jarosite, schwertmannite) and oxyhydroxides (goethite, ferrihydrite), both with a variable degree of crystallinity. The mobility of Zn, Cd, and Cu was highly affected by pH, producing a stronger leaching in depth; their retention was related to the forms of precipitated aluminium and, in the case of Cu, also to the neoformation of hydroxysulfate.

关键词： arsenic heavy metals oxidation pyrite-tailing soil

Security-constrained model for integrated power and natural-gas system

在线全文

学校读者我要写书评

暂无评论

Journal of modern Power Systems and Clean Energy 2017年第3期5卷 326-336页

作者： Carlos m.CORREA-POSADA Pedro SánCHEZ-martín Sara LUmBRERAS Xm Compania de Expertos en MercadosMedellı´nColombia Technological Research Institute(IIT) ICAI School of EngineeringComillas Pontifical UniversityMadridSpain

One of the main factors impacting the reliability of energy systems nowadays is the growing interdependence between electricity and gas networks due to the increase in the installation of gas-fired units. Securityconstrained unit commitment(SCUC) models are used to economically schedule generating units without compromising the system reliability. This paper proposes a novel SCUC formulation that includes dynamic gas constraints,such as the line pack, and transmission contingencies in power and gas networks for studying the integrated system reliability. A Benders’ decomposition with linear programming techniques is developed to be able to study large systems. By including dynamic gas constraints into the SCUC, the proposed model accounts for the flexibility and reliability that power systems require from gas systems in the short term. Case studies of different size and complexity are employed to illustrate how the reliability of one system is affected by the reliability of the other. These experiments show how both systems operate in a secure way(by including contingencies) increases operating costs by approximately 9% and also show how these costs can vary by 24% depending on the line pack scheduling.

关键词： Benders’decomposition natural gas Reliability Security-constrained unit commitment

Classification of anemia for gastroenterologists

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2009年第37期15卷 4627-4637页

作者： Jose Antonio moreno Chulilla maria Soledad Romero Colás martín Gutiérrez martín Department of Hematology University Hospital "Lozano Blesa" University of Zaragoza C/San Juan Bosco 15 Zaragoza 50009 Spain

most anemia is related to the digestive system by dietary deficiency, malabsorption, or chronic bleeding. We review the World Health Organization definition of anemia, its morphological classifi cation (microcytic, macrocytic and normocytic) and pathogenic classi-fication (regenerative and hypo regenerative), and integration of these classifications. Interpretation of laboratory tests is included, from the simplest (blood count, routine biochemistry) to the more specific (iron metabolism, vitamin B12, folic acid, reticulocytes, erythropoietin, bone marrow examination and Schilling test). In the text and various algorithms, we propose a hierarchical and logical way to reach a diagnosis as quickly as possible, by properly managing the medical interview, physical examination, appropriate laboratory tests, bone marrow examination, and other comple-mentary tests. The prevalence is emphasized in all sections so that the gastroenterologist can direct the diagnosis to the most common diseases, although the tables also include rare diseases. Digestive diseases potentially causing anemia have been studied in preference, but other causes of anemia have been included in the text and tables. Primitive hematological diseases that cause anemia are only listed, but are not discussed in depth. The last section is dedicated to simplifying all items discussed above, using practical rules to guide diagnosis and medical care with the greatest economy of resources and time.

关键词： Anemia microcytic anemia Iron Deficiency diseases macrocytic anemia normocytic anemia

Supercritical synthesis of platinum-modified titanium dioxide for solar fuel production from carbon dioxide

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2017年第4期38卷 636-650页

作者： Susana Tostón Rafael Camarillo Fabiola martínez Carlos Jiménez Jesusa Rincón University of Castilla‐La mancha Department of Chemical Engineering Faculty of Environmental Sciences and Biochemistry Avda. Carlos III s/n 45071 Toledo Spain

This paper investigates the properties of TiO2‐based photocatalysts synthesised under ***,the characteristics of Pt dispersed on TiO2catalysts obtained in supercriticalCO2are discussed and compared with those of commercial *** photocatalytic activity of thesynthesised catalysts in the CO2photoreduction reaction to produce solar fuel is *** mainconclusion of the study is that photocatalysts with better or similar features,including high surfacearea,crystallisation degree,hydroxyl surface concentration,pore volume,absorbance in the visiblerange and methane production rate,to those of commercial TiO2may be produced for the reductionof CO2to fuel by synthesis in supercritical media.

关键词： Titanium dioxide Platinum Photocatalyst metal dispersion Carbon dioxide photoreduction

Proteomic profile of human monocytic cells infected with dengue virus

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2016年第11期6卷 914-923页

作者： Viviana martínez-Betancur marleín martínez-Gutierrez Programa de Estudio y Control de Enfermedades Tropicales-PECET Universidad de Antioquia Grupo de Investigación en Ciencias Animales-GRICA Facultad de Medicina Veterinaria y Zootecnia Universidad Cooperativa de Colombia

Objective: To identify the changes in the proteome of U937 cells infected with dengue virus(DEnV).methods: In this study, differentiated U937 cultures were infected with two DEnV-2strains, one of which was associated with dengue(DEnV-2/nG) and the other one with severe dengue(DEnV-2/16681), with the aim of determining the cellular proteomic profiles under different infection conditions. Cellular proteins were extracted and separated by two-dimensional electrophoresis, and those proteins with differential expression profiles were identified by mass spectrometry. The obtained results were correlated with cellular viability, the number of infectious viral particles, and the viral DnA/protein ***: In comparison with non-infected cultures, in the cells infected with the DEnV-2/nG strain, nine proteins were expressed differentially(five were upregulated and four were downregulated); in those cultures infected with the DEnV-2/16681 strain, six proteins were differentially expressed(two were downregulated and four were upregulated). The downregulated proteins included fatty acid-binding protein, heterogeneous nuclear ribonucleoprotein 1, protein disulfide isomerase, enolase 1, heat shock 70 k Da protein 9, phosphotyrosyl phosphatase, and annexin IV. The upregulated proteins included heat shock 90 k Da protein AA1, tubulin beta, enolase 1, pyruvate kinase,transaldolase and phospholipase ***: Because the monocyte/macrophage lineage is critical for disease pathogenicity, additional studies on these proteins could provide a better understanding of the cellular response to DEnV infection and could help identify new therapeutic targets against infection.

关键词： Dengue virus Proteomic macrophages monocytes U937 cells