检索结果-南通市图书馆

Testing carbonate chemostratigraphy across differentiated ancient shallow-platform environments(Early Kimmeridgian,S Iberia)

引用

Geoscience Frontiers 2019年第6期10卷 2203-2218页

作者： Rute Coimbra Beatriz Marques Federico Oloriz GeoBioTec Departamento de GeocienciasUniversidade de AveiroPortugal MARE Departamento de Ciencias da TerraUniversidade de CoimbraPortugal Faculdade de Ciencias e Tecnologia Universidade Nova de LisboaPortugal departamento de Estratigrafia y Palaeontologia Universidad de GranadaSpain

Shallow-platform settings with marked differences in paleoplatform bottom physiography influence the degree of connection with oceanic waters and overall circulation patterns,even when sharing the same palaeoclimatic *** Kimmeridgian shallow-marine settings have been explored to test the sensitivity and reliability of carbonate chemostratigraphy to detect such *** integrated overview of the obtained elemental trends depicted four major facies,shared along specific stratigraphic intervals of both depositional *** obliterated original geochemical signals only throughout the siliciclastics-rich interval,corresponding to the most landward *** the remaining facies,elemental features could be attributed to the differential action of forcing mechanisms operating along the south-Iberian paleomargin during Kimmeridgian *** highest degree of continental influence can be recognized by a strong relationship between Fe and Mn for the most proximal setting,which fades out along the mixed carbonate-fine siliciclastic rhythmic deposition in more open settings.A characteristic geochemical signature of progressively more positiveδ^(13)C values and significantly higher Sr content is identified for the interval dominated by biogenic sponge *** a local response is related to local forcing by upwelling in the surroundings of a coral *** geochemical signature of a hydrothermal origin can be clearly differentiated from the influence of mere terrigenous ***,the decoupling of Fe and Mn along marginal settings is the clue to detecting major events of palaeogeographic *** temporal variations in Mg content along both studied sections are attributed to tectonic activity influencing nearshore/coastal water *** integrating chemostratigraphic information and complementary evidence,the palaeoenvironmental mechanisms promoting differentiated sedimentary records along ancient subtropical,shallow

关键词： Palaeoenvironment Carbonate chemostratigraphy Shallow-water carbonates Diagenesis Kimmeridgian

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Host-parasite interactions under extreme climatic conditions

引用

Current Zoology 2011年第3期57卷 390-405页

作者： J. MARTINEZ S. MERINO departamento de Microbiologfa y Parasitologfa Facultad de Farmacia Universidad de Alcala Alcala de Henares Madrid Spain departamento de Ecologfa Evolutiva Museo Nacional de Ciencias Naturales Consejo Superior de Investigaciones Cientfficas Madrid Spain

The effect that climatic changes can exert on parasitic interactions represents a multifactor problem whose results are difficult to predict. The actual impact of changes will depend on their magnitude and the physiological tolerance of affected organisms. When the change is considered extreme （i.e. unusual weather events that are at the extremes of the historical distribution for a given area）, the probability of an alteration in an organisms＇ homeostasis increases dramatically. However, factors determining the altered dynamics of host-parasite interactions due to an extreme change are the same as those acting in response to changes of lower magnitude. Only a deep knowledge of these factors will help to produce more accurate predictive models for the effects of extreme changes on parasitic interactions. Extreme environmental conditions may affect pathogens directly when they include free-living stages in their life-cycles and indirectly through reduced resource availability for hosts and thus reduced ability to produce efficient anti-parasite defenses, or by effects on host density affecting transmission dynamics of diseases or the frequency of intraspecific contact. What are the consequences for host-parasite interactions？ Here we summarize the present knowledge on three principal factors in determining host-parasite associations; biodiversity, population density and immunocompetence In addition, we analyzed examples of the effects of environmental alteration of anthropogenic origin on parasitic systems because the effects are analogous to that exerted by an extreme climatic change [Current Zoology 57 （3）： 390405, 2011].

关键词： Biodiversity Climate change Immunocompetence Parasite-host interactions Pollution Population density

来源：

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

Inference for a truncated positive normal distribution

引用

Applied Mathematics(A Journal of Chinese Universities) 2018年第2期33卷 163-176页

作者： Hector J.Gomez Neveka M.Olmos Hector Varela Heleno Bolfarine departamento de Ciencias Matematicas y Ffsicas Facultad de IngenierlaUniversidad Catolica de TemucoTemucoChile departamento de Matematicas Facultad de Ciencias BasicasUniversidad de AntofagastaAntofagastaChile departamento de Estatfstica IMEUniversidade de Sao PauloSao PauloBrazil

The main object of this paper is to study an extension of the half normal distribution defined by adding a positive truncation to it. The new model is more flexible than the half-normal distribution and contains the half normal distribution as a special case. Properties of this distribution, such as moments, hazard function and entropy are studied and parameters estimation is dealt with by using inoinents and inaxiinuin likelihood. A real data application indicates good fit performance of the new model when compared to other competitors in litera- tures.

关键词： half-normal distribution maximum likelihood truncation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Distribution of the related weevil species Sitophilus oryzae and S. zeamais in Brazil

引用

Insect Science 2013年第6期20卷 763-770页

作者： Alberto S. Correa Luiz Orlando de Oliveira Lucas S. Braga Raul Narciso C. Guedes departamento de Entomologia Universidade Federal de Vicosa Vicosa Brazil departamento de Bioquimica e Biologia Molecular Universidade Federal de Vicosa Vicosa Brazil

The genus Sitophilus （Coleoptera： Curculionidae） encompasses species of great economic importance as stored grain pests worldwide. Among these species, the maize and the rice weevils （Sitophilus zeamais and Sitophilus oryzae, respectively） are partic- ularly important in warmer climates. These two weevils exhibit closely morphological and ecological resemblance making difficult their proper identification and recognition of their distribution in grain-producing regions. Both species are recorded in South America and particularly in Brazil, but their respective distribution and prevalence were not yet assessed in the region. Therefore, several insect samples throughout Brazil were collected and subjected to morphological identification using male genitalia and also using molec- ular identification with species-specific primers designed for clear recognition of both the species. The primers were designed for the specific amplification of a gene fragment of the cytochrome oxidase subunit I, which exhibited high specificity during our prelimi- nary experiments with insects from six populations of known species （either S. zeamais or S. oryzae）. Both identification strategies provided the same results indicating preva- lence of the maize weevil S. zeamais throughout the country. Two hypotheses may explain such prevalence：（i） the likely host preference ofS. zeamais for maize because this is the most cultivated cereal in Brazil, and （ii） the prevalence ofS. zeamais in tropical regions as compared with S. oryzae, which is more disseminated in subtropical and temperate regions.

关键词： cytochrome oxidase subunit I distribution maize weevil rice weevil South America

来源：

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

Environmental parameters and tree physiology in two semiarid land use systems in Brazil

引用

Journal of Forestry Research 2019年第2期30卷 397-407页

作者： Marlete Moreira Mendes Ivanov Claudivan Feitosa de Lacerda Francisco Eden Fernandes Paiva Ana Clara Rodrigues Cavalcante Teogenes Senna de Oliveira departamento de Biologia Universidade Federal do Piaui departamento de Engenharia Agricola Campus do PiciUniversidade Federal do Ceara Embrapa Caprinos e Ovinos departamento de Solos Universidade Federal de Vicosa

To determine if reduced tree densities(number of trees per unit area) lead to changes in micro-meteorological and tree physiological characteristics, two areas with different tree densities were assessed. One was an agrosilvopastoral system(AGP) with low tree density, and the other, a secondary forest(SF) with greater tree numbers, both located in a semiarid region of Brazil. Data were collected simultaneously by two automated weather stations: rainfall, air(T_a) and soil temperatures(T_(s5 cm)), relative humidity(RHair), photosynthetically active radiation(PAR), soil moisture at two depths(M_(s30 cm)and M_(s50 cm)),and wind velocity(Vw). Net photosynthesis in Cordia oncocalyx Allema?o trees was measured with an infrared gas analyzer in February, March, May, July, August and September 2011, which encompasses a rainy period followed by a dry period. Average values of Ta, T_(s5 cm), Vwand PAR were greater and average values of RHairand M_(s50 cm) were lesser in the AGP. Photosynthetic rates were greater in plants growing under the AGP at the onset of the dry season when Vw, PAR and T_(s5 cm)were greater and M_(s50 cm) was lesser. Photosynthetic rates correlated strongly with physical parameters during the dry season, especially under SF. Differences in tree numbers between AGP and SF led to differences in physical environmental parameters;however, the latter had less influence on photosynthetic rates in C. oncocalyx during the rainy season. During the dry season, all physical parameters had an impact on net photosynthesis under SF but not under AGP. This indicates a certain independence of plants in AGP.

关键词： Agrosilvopastoral system Net photosynthesis Secondary forest Tree density

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

ＣＯＭＰＬＥＸＩＴＹＯＦＬＡＲＧＥＴＩＭＥＢＥＨＡＶＩＯＵＲＯＦＥＶＯＬＵＴＩＯＮＥＱＵＡＴＩＯＮＳＷＩＴＨＢＯＵＮＤＥＤＤＡＴＡ

引用

Chinese Annals of Mathematics,Series B 2002年第2期23卷 293-310页

作者： J.L.VZQUEZ E.ZUAZUA departamento de Matematicas Universidad AutonomaDepartamento de Matematica AplicadaUniversidadComplutense 28049MadridSpain28040 M

The authors study the asymptotic behaviour of solutions of the heat equation and a number of evolution equations using scaling techniques. It is proved that in the framework of bounded data stabilization need not occur and the general asymptotic behaviour is complex. This behaviour reflects for large times, even on compact sets, the complexity of the initial data at infinity.

关键词： Asymptotic behaviour Scaling Omega-limit Heat equation Hyperbolic conservation laws

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fibonacci Sequences and the Multiperiodicity of the Variable Star UW Herculis

引用

Chinese Journal of Astronomy and Astrophysics 2003年第3期3卷 235-240页

作者： Juan Garcia Escudero departamento de Fisica Universidad de Oviedo 33007 Oviedo Spain

We present an application of the methods recently developed for the study of quasicrystal structures to the analysis of multiperiodicity of semiregular variables. A light curve analysis of UW Her shows frequencies that can be included within the general scheme characterizing the Fourier spectra of Fibonacci quasiperiodic sequences. The analysed data come from the BAA Variable Star Section computerised archive.

关键词： stars: variables

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Integrated Groups and Smooth Distribution Groups

引用

Acta Mathematica Sinica,English Series 2007年第1期23卷 57-64页

作者： Pedro J.MIANA departamento de Matemáticas Universidad de Zaragoza50009Spain

In this paper, we prove directly that α-times integrated groups define algebra homomorphisms. We also give a theorem of equivalence between smooth distribution groups and α-times integrated groups.

关键词： integrated groups distribution groups Weyl fractional calculus

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Glutamine is highly effective in preventing in vivo cobalt-induced oxidative stress in rat liver

引用

World Journal of Gastroenterology 2005年第23期11卷 3533-3538页

作者： Soledad Gonzales Ariel H.Polizio María A.Erario María L.Tomaro departamento de Química Biológica

AIM: To evaluate the in vivo effect of glutamine on cobaltgenerated oxidative stress and (HO-1) induction in rat ***: Fasted female Wistar rats received a single injection of cobalt chloride (375 μmol/kg body weight) and then were killed at different times. Lipid peroxidation and soluble and enzymatic antioxidant defense system (reduced glutathione (GSH), catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD)) were measured in liver homogenates. Ferritin and ferritin iron contents as well as heme oxygenase-1 (HO-1) activity and expression were also determined. The antioxidant properties of glutamine (Gin) were also evaluated. RESULTS: Cobalt chloride increased lipid peroxidation (50% over control values) 1 h after treatment. GSH reached a minimum at 3 h (40%) increasing thereafter. Twelve hours after CoCl2 injection, the antioxidant enzymes CAT, GSH-Px and SOD also diminished by about 30%. Heme oxygenase-1 induction was observed 6 h after treatment reaching a maximum value of 14-fold over the controls, 12 h after cobalt treatment. A 1.7-fold increase in ferritin and ferritin-bound iron 24 h after treatment were also obtained. Administration of glutamine (300 mg/kg body weight) by gavage 24 h before CoCl2 treatment entirely prevented the increase in thiobarbituric acid reactive substances (TBARS) content, the decrease in GSH levels, and partially reverted heme oxygenase-1 induction. CONCLUSION: These results suggested that a natural product such as glutamine prevents glutathione depletion and consequently heme oxygenase induction.

关键词： Oxidative stress Heme oxygenase Glutathione Glutamine Iron Liver

来源：

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

A Note on Tropical Triangles in the Plane

引用

Acta Mathematica Sinica,English Series 2009年第11期25卷 1775-1786页

作者： M.ANSOLA M.J.de la PUENTE departamento de Algebra Facultad de Matemáticas Universidad Complutense

We define transversal tropical triangles （affine and projective） and characterize them via six inequalities to be satisfied by the coordinates of the vertices. We prove that the vertices of a transversal tropical triangle are tropically independent and they tropically span a classical hexagon whose sides have slopes ∞, 0, 1. Using this classical hexagon, we determine a parameter space for transversal tropical triangles. The coordinates of the vertices of a transversal tropical triangle determine a tropically regular matrix. Triangulations of the tropical plane are obtained.

关键词： tropical triangles tropical triangulation linear inequalities convexity tropical semi-field

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：