检索结果-南通市图书馆

Integrative Zoology 2017年第1期12卷 49-60页

作者： Francisco cARRO ramón c.soriguer Doñana Biological Station(cSIc) the Monitoring Team on Natural Resources and Processes of the Doñana Biological Station Ethology and Biodiversity conservation SevillaSpain

The Iberian hare(Lepus granatensis)is a widely distributed endemic species in the Iberian Peninsula.To improve our knowledge of its population dynamics,the relative abundance and population trends of the Iberian hare were studied in the autumns of 1995-2012 in a protected area(Doñana national Park)by spotlighting in 2 different habitats:marshland and ecotones.The average relative abundance was 0.38 hare/km(SD=0.63)in the marshland and 3.6 hares/km(SD=4.09)in ecotones.The Iberian hare population exhibited local interannual fluctuations and a negative population trend during the study period(1995-2012).The results suggest that its populations are in decline.The flooding of parts of the marshland in June,July and October favor hare abundance in the ecotone.Hare abundance in the marshland increases as the flooded surface area increases in October.These effects are more pronounced if the rains are early(October)and partially flood the marsh.By contrast,when marsh grasses and graminoids are very high and thick(as measured using the aerial herbaceous biomass[biomass marshland]as a proxy),the abundance of hares decreases dramatically as does the area of the marsh that is flooded(in november).

关键词： Doñana Iberian Peninsula Lepus granatensis population dynamics trends

Solution of the center Problem for a class of Polynomial Differential Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第7期40卷 1685-1696页

作者： chang Jian LIU Jaume LLIBRE Rafael ramíREZ Valentín ramíREZ School of Mathematics (Zhuhai) Sun Yat-sen University Departament de Matemàtiques Universitat Autònoma de Barcelona Departament d'Enginyeria Informàtica i Matemàtiques Universitat Rovira i Virgili

consider the polynomial differential system of degree m of the form ■ where μ and ν are real numbers such that（μ2+ ν2）(μ + ν（m-2）)（a1～2+ a2～2） ≠0, m > 2 and Ωm-1（x, y） is a homogenous polynomial of degree m-1. A conjecture, stated in J. Differential Equations 2019,suggests that when ν = 1, this differential system has a weak center at the origin if and only if after a convenient linear change of variable（x, y） →（X, Y） the system is invariant under the transformation（X, Y, t） →（-X, Y,-t）. For every degree m we prove the extension of this conjecture to any value of ν except for a finite set of values of μ.

关键词： center problem polynomial differential system 34c07 34c20

Early Phases of Star Formation: Testing chemical Tools

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第1期24卷 96-118页

作者： n.c.Martinez S.Paron cOnIcET-Universidad de Buenos Aires.Instituto de Astronomía y Física del Espacio Ciudad Universitaria(C1428EGA)Ciudad Autónoma de Buenos AiresArgentina

Star-forming processes strongly influence the ISM chemistry.nowadays,many high-quality databases are available at millimeter wavelengths.Using them,it is possible to carry out studies that review and deepen previous results.If these studies involve large samples of sources,it is preferred to use direct tools to study the molecular gas.With the aim of testing these tools such as the use of the Hcn/Hnc ratio as a thermometer,and the use of H^(13)cO^(+),Hc_(3)n,n_(2)H^(+) and c_(2)H as "chemical clocks," we present a molecular line study toward 55 sources representing massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDcs),highmass protostellar objects(HMPOs),hot molecular cores(HMcs) and ultracompact H II regions.We found that the use of the Hcn/Hnc ratio as a universal thermometer in the ISM should be taken with care because the Hcn optical depth is a big issue that can affect the method.Hence,this tool should be utilized only after a careful analysis of the Hcn spectrum,checking that no line,neither the main nor the hyperfine ones,presents absorption features.We point out that the analysis of the emission of H^(13)cO^(+),Hc_(3)n,n_(2)H^(+) and c_(2)H could be useful to trace and distinguish regions among IRDcs,HMPOs and HMcs.The molecular line widths of these four species increase from the IRDc to the HMc stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular clumps.Our results not only contribute with more statistics,acting as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.

关键词： stars:formation ISM:molecules ISM:clouds

Impact of STAT-signaling pathway on cancer-associated fibroblasts in colorectal cancer and its role in immunosuppression

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2024年第5期16卷 1705-1724页

作者： Damián Sánchez-ramírez Mónica G Mendoza-Rodríguez Omar R Alemán Fernando A candanedo-González Miriam Rodríguez-Sosa Juan JoséMontesinos-Montesinos Mauricio Salcedo Ismael Brito-Toledo Felipe Vaca-Paniagua Luis I Terrazas Unidad de Investigacion en Biomedicina Facultad de Estudios Superiores IztacalaUniversidad Nacional Autonoma de MexicoTlalnepantla 54090Estado de MexicoMexico Department of Biology Facultad de QuimicaUniversidad Nacional Autonoma de MexicoCiudad UniversitariaMexico City 04510Mexico Department of Pathology National Medical Center Century XXIInstituto Mexicano del Seguro SocialMexico City 06720Mexico Laboratorio de células Troncales Mesenquimales Unidad de Investigación Médica en Enfermedades OncológicasHospital de Oncología Centro Medico Nacional Siglo XXIInstituto Mexicano del Seguro SocialMexico City 06720Mexico Unidad de Investigacion en Biomedicina y Oncologia Genomica Instituto Mexciano del Seguro SocialMexico City 07300Mexico Servicio de colon y Recto Hospital de Oncología Centro Medico Nacional Siglo XXIInstituto Mexicano del Seguro SocialMexico City 06720Mexico Laboratorio nacional en Salud Facultad de Estudios Superiores IztacalaUniversidad Nacional Autónoma de MéxicoTlalnepantla 54090Estado de MexicoMexico

colorectal cancer(cRc)remains one of the most commonly diagnosed and deadliest types of cancer worldwide.cRc displays a desmoplastic reaction(DR)that has been inversely associated with poor prognosis;less DR is associated with a better prognosis.This reaction generates excessive connective tissue,in which cancer-associated fibroblasts(cAFs)are critical cells that form a part of the tumor microenvironment.cAFs are directly involved in tumorigenesis through different mechanisms.However,their role in immunosuppression in cRc is not well understood,and the precise role of signal transducers and activators of transcription(STATs)in mediating cAF activity in cRc remains unclear.Among the myriad chemical and biological factors that affect cAFs,different cytokines mediate their function by activating STAT signaling pathways.Thus,the harmful effects of cAFs in favoring tumor growth and invasion may be modulated using STAT inhibitors.Here,we analyze the impact of different STATs on cAF activity and their immunoregulatory role.

关键词： cancer-associated fibroblasts Signal transducer and activator of transcription signaling colorectal cancer Immunity Immunosuppression

chitosan nanoparticles as Biostimulant in Lettuce (Lactuca sativa L.) Plants

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2024年第4期93卷 777-787页

作者： Silvia c.ramírez-Rodríguez Pablo Preciado-Rangel Marcelino cabrera-De La Fuente Susana González-Morales Hortensia Ortega-Ortiz Tecnológico nacional de México Instituto Tecnológico de TorreónEjido AnaTorreónCoahuila27170México Departamento de Horticultura Universidad Autónoma Agraria Antonio NarroSaltillo25315México Departamento de Materiales Avanzados Centro de Investigación en Química AplicadaSaltilloCoahuila25294México

Biodegradable nanoparticles such as chitosan nanoparticles (cSnPs) are used in sustainable agriculture since theyavoid damage to the environment;cSnPs have positive effects such as the accumulation of bioactive compoundsand increased productivity in plants. This study aimed to investigate the impact of applying cSnPs on lettuce,specifically focusing on enzymatic activity, bioactive compounds, and yield. The trial was conducted using a completelyrandomized design, incorporating cSnPs: 0, 0.05, 0.1, 0.2, 0.4, and 0.8 mg mL−1. The doses of 0.4 mg mL−1improve yields up to 24.6% increases and 0.1 mg mL−1 of cSnPs increases total phenols by 31.2% and antioxidantcapacity by 34.6%. In addition, when low concentrations of cSnPs (0.05 and 0.1 mg L−1) were applied, anincrease in catalase was determined. The cSnPs represent a good alternative to be used as a biostimulant in sustainableagriculture because they improve the yield and quality of lettuce by increasing the bioactive compounds.

关键词： Biostimulant bioactive compounds enzymatic activity

Photosynthetic Gas Exchange and nitrogen Assimilation in Green Bean Plants Supplied with Two Sources of Silicon

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2024年第5期93卷 963-980页

作者： Julio c.Anchondo-Páez Esteban Sánchez carlos A.ramírez-Estrada Alondra Salcido-Martínez Erick H.Ochoa-chaparro Department of Plant Physiology Centro de Investigación en Alimentación y DesarrolloCiudad Delicias33089México

Beans contain a wide range of vitamins,proteins,calcium,and zinc which make them an important food source for many countries.To meet the demand for bean production worldwide,large amounts of fertilizers and pesticides are used.However,the cost of production and environmental impact increases.To produce food sustainably,the use of beneficial nutrients such as silicon as a biostimulant has been proposed.However,information about the effect of different sources of silicon on the metabolism of bean plants is scarce.Bean plants cv.Strike were grown in pots for 60 days and the effect of foliar application of silicon nanoparticles and the silicon-based biostimulant codasilat 4 concentrations(0,1,2,and 4 mM)on total biomass,yield,photosynthetic pigment concentration,photosynthetic activity,stomatal conductance,transpiration rate,chlorophyll fluorescence,and nitrogen assimilation were evaluated.The results obtained showed that the supply of silicon at a dose of 1 mM functioned as a biostimulant,favoring gas exchange and nitrogen assimilation within the plant,which stimulated growth and yield.The results of this research work allowed a better comprehension of the effects of silicon application through silicon nanoparticles and the biostimulant codasilon the physiology of green bean plants.

关键词： nanoparticles silicon Phaseolus vulgaris L.

Airway management of a patient with linear immunoglobulin A bullous dermatosis:A case report

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of clinical cases 2024年第13期12卷 2263-2268页

作者： Olga c nin Robert Hutnik neil n chheda David Hutchinson Department of Anesthesiology University of Florida College of MedicineGainesvilleFL 32610United States Department of Otolaryngology University of Florida College of MedicineGainesvilleFL 32610United States

BAcKGROUnD There is limited literature on managing the airway of patients with linear immunoglobulin A(IgA)bullous dermatosis,a rare mucocutaneous disorder that leads to the development of friable bullae.careful clinical decision making is necessary when there is a risk of bleeding into the airway,and a multidisciplinary team approach may lead to decreased patient morbidity during these high-risk scenarios,especially when confronted with an unusual cause for bleeding.cASE SUMMARY A 45-year-old African American female presented to our ambulatory surgical center for right corneal transplantation due to corneal perforation after blunt trauma in the setting of cicatricial conjunctivitis and diffuse corneal neovascularization from linear IgA bullous dermatosis.The diagnosis of IgA dermatosis was recent,and the patient had been lost to follow-up.The severity of the disease and extent of airway involvement was unknown at the time of the surgery.Significant airway bleeding was noticed upon intubation and the otorhinolaryngology team had to be called to the operating room.The patient required transfer to the intensive care unit where a multidisciplinary team was involved in her case.The patient was extubated on postoperative day 4.cOncLUSIOn A multidisciplinary approach to treating this disease is the best course of action before a surgical procedure.In our case,key communication between the surgery,anesthesia,and dermatology teams led to the quick and safe treatment of our patient’s disease.Ambulatory surgery should not be considered for these cases unless they are in full remission and there is no mucous membrane involvement.

关键词： Airway management Bleeding risk Linear immunoglobulin A bullous dermatosis Multidisciplinary approach Outpatient procedure case report

nanoparticle Exsolution on Perovskite Oxides:Insights into Mechanism,characteristics and novel Strategies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

nano-Micro Letters 2024年第2期16卷 312-346页

作者： Yo Han Kim Hyeongwon Jeong Bo‑ram Won Hyejin Jeon chan‑ho Park Dayoung Park Yeeun Kim Somi Lee Jae‑ha Myung Department of Materials Science and Engineering Incheon National UniversityIncheon 22012Republic of Korea

Supported nanoparticles have attracted considerable attention as a promising catalyst for achieving unique properties in numerous applications,including fuel cells,chemical conversion,and batteries.nanocatalysts demonstrate high activity by expanding the number of active sites,but they also intensify deactivation issues,such as agglomeration and poisoning,simultaneously.Exsolution for bottomup synthesis of supported nanoparticles has emerged as a breakthrough technique to overcome limitations associated with conventional nanomaterials.nanoparticles are uniformly exsolved from perovskite oxide supports and socketed into the oxide support by a one-step reduction process.Their uniformity and stability,resulting from the socketed structure,play a crucial role in the development of novel nanocatalysts.Recently,tremendous research efforts have been dedicated to further controlling exsolution particles.To effectively address exsolution at a more precise level,understanding the underlying mechanism is essential.This review presents a comprehensive overview of the exsolution mechanism,with a focus on its driving force,processes,properties,and synergetic strategies,as well as new pathways for optimizing nanocatalysts in diverse applications.

关键词： Supported nanoparticle Exsolution In situ growth Mechanism Perovskite oxide catalyst

Twenty years of population dynamics in European beech-oak forest at their rear range margin anticipate changes in its structure and composition

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2024年第3期11卷 358-370页

作者： álvaro Rubio-cuadrado Iciar Alberdi Isabel canellas Fernando Montes Jesús Rodríguez-calcerrada Rosana López Guillermo G.Gordaliza María Valbuena-carabana nikos nanos ramón Perea Luis Gil Departamento de dinamica y gestion forestal Instituto de Ciencias Forestales(ICIFOR-INIA)CSICCtra.La Coruna km 7.528040MadridSpain Departamento de Sistemas y Recursos naturales Escuela Tecnica Superior de Ingeniería de MontesForestal y del Medio NaturalUniversidad Politecnica de Madrid.Ciudad Universitaria s/n28040MadridSpain School of Forestry and natural Environment Aristotle University of ThessalonikiUniversity Campus54124ThessalonikiGreece

There is an increasing interest in restoring degraded forests,which occupy half of the forest areas.Among the forms of restoration,passive restoration,which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management,is gaining attention.natural dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions,composition and abundance of species,and the successional character of these species.Here,we study the natural dynamics of a mixed forest located in central Spain,which maintained an open forest structure,due to intensive use,until grazing and cutting were banned in the 1960s.The most frequent woody species in this forest are Fagus sylvatica,Quercus petraea,Quercus pyrenaica,Ilex aquifolium,Sorbus aucuparia,Sorbus aria and Prunus avium,with contrasting shade and drought tolerance.These species are common in temperate European deciduous forest and are found here near their southern distribution limit,except for Q.pyrenaica.In order to analyze forest dynamics and composition,three inventories were carried out in 1994,2005 and 2015.Our results show that,despite the Mediterranean influence,the natural dynamics of this forest has been mainly determined by different levels of shade tolerance.After the abandonment of grazing and cutting,Q.pyrenaica expanded rapidly due to its lower shade tolerance,whereas after canopy closure and forest densification,shade-tolerant species gained ground,particularly F.sylvatica,despite its lower drought and late-frost tolerance.If the current dynamics continue,F.sylvatica will overtake the rest of the species,which will be relegated to sites with shallow soils and steep slopes.Simultaneously,all the multi-centennial beech trees,which are undergoing a rapid mortality and decline process,will disappear.

关键词： Forest succession Secondary forest Woodland Mixed forest competition Recruitment

Empirical model for fusion cross sections of ca-induced reactions

在线全文

学校读者我要写书评

暂无评论

chinese Physics c 2024年第3期48卷 126-132页

作者： Reddi Rani.L n.Sowmya K.n Sridhar H c.Manjunatha M.M.Armstrong Arasu Department of Physics St.Joseph's College(Autonomous)Affiliated to Bharathidasan UniversityTiruchirappalli620002TNIndia Department of Physics Govt.First.Grade CollegeChikkaballapur-562101KarnatakaIndia Department of Physics Govt.First.Grade CollegeMalur-563160KarnatakaIndia Department of Physics Govt.First.Grade CollegeDevanahalli-562110KarnatakaIndia

A new empirical formula for the astrophysical S-factor has been suggested as a function of the coulomb interaction parameter,center of mass energy,and barrier height.About 22 fusion reactions with ^(40,48)ca as projectiles were considered for different targets,leading to compound nuclei with atomic and mass numbers varying between 40≤Z≤≤Z≤112 and 88≤A≤27888≤A≤278,respectively.The fusion cross-sections have been estimated using the geometric factor,the Gamow-Sommerfield factor,and the empirical formula for the S-factor.This study's findings showed better agreement with those of available experiments when compared to Wong's formula.The present work leads to a smaller standard deviation value than Wong's formula when used to correlate the experimental data of calcium-induced fusion reactions.Wong's formula provides a good approximation of fusion cross-sections when the center of mass energy is below the fusion barrier when compared to above the fusion barrier.

关键词： fusion cross-sections Wong formula Gamow-Sommerfield-factor Geometric-factor S-factor