检索结果-南通市图书馆

Evaluation of the Level of Pollution by Heavy Metals of Market Garden Soils along the Chari River in Ndjamena: Case of the 9th and 7th Districts

引用

Agricultural.Sciences 2024年第8期15卷 939-961页

作者： Kotva Wana Mackaye Hassane Taisso Likius Andossa Béral.Djétenbé Laboratoire Gosciences Dpartement des Sciences de la Terre Facult des Sciences Universit de NDjamena NDjamena Chad Laboratoire Gosciences Dpartement des Sciences de la Terre Facult des Sciences Universit de Mongo Mongo Chad Laboratoire Sol et Environnement (LASEN) Dpartement des Sciences de la Terre Facult des Sciences Universit de Ngaoundr Ngaoundr Cameroun

The main aim of this study was to characterize the metal content of soils used for market gardening along the Chari river: the 7th and 9th districts of NDjaména. To achieve this, two sites were selected: Gassi and Walia, and two control sites (Gassi and Walia). A total of fifty (50) soil samples were taken (24 from the Gassi site, 24 from the Walia site and 2 as control soils) and then analyzed to determine a number of physico-chemical parameters (pH, OM and electrical conductivity) and heavy metal concentrations in the various soils. The TME content (As, Cd, Cu, Cr, Ni, Pb, Hg and Zn) of the soils was determined by plasma-coupled Atomic Emission Spectrometry. In order to assess the level of contamination in Gassi and Walia soils, the geoaccumulation index (GeoIndex), contamination factor and degree of contamination were calculated. Results for physico-chemical parameters revealed that pH ranged from acidic (4.6) to moderately neutral.(6.5), electrical conductivity was higher in cultivated soils (mean 292.14 μs/cm) than in control soils (mean 149.33 μs/cm), and soils were rich in organic matter. Overal., heavy metal concentrations in cultivated soils were higher than in control soils. The pollution estimate shows that soils in the area have no moderate contamination. The increase in TME concentrations in cultivated soils is thought to be due to the input of agricultural.inputs to the soil. However, these levels are below the Average shale reference and Canadian guidelines for agricultural.soil quality. Principal component analysis shows that metals are positively and significantly correlated with each other, and negatively and moderately significantly correlated with each other.

关键词： Contamination Agricultural.Soils City of N’Djaména ETM Gassi Walia

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

Spatial Variability and Cartography of Maximum Annual Daily Rainfall under Different Return Periods in Northern Algeria

引用

Journal of Mountain Science 2015年第6期12卷 1403-1421页

作者： MEDDI Mohamed toumi Samir National High School of Hydraulic (ENSH)

The estimation of precipitation quantiles has always been an area of great importance to meteorologists, hydrologists, planners and managers of hydrotechnical infrastructures. In many cases, it is necessary to estimate the values relating to extreme events for the sites where there is little or no measurement, as well as their return periods. A statistical approach is the most used in such cases. It aims to find the probability distribution that best fits the maximum daily rainfall values. In our study, 231 rainfall stations were used to regionalize and find the best distribution for modeling the maximum daily rainfall in Northern Algeria. The L-moments method was used to perform a regionalization based on discordance criteria and homogeneity test. It gave rise to twelve homogeneous regions in terms of LCoefficient of variation(L-CV), L-Skewness(L-CS) and L-Kurtosis(L-CK). This same technique allowed us to select the regional probability distribution for each group using the Z statistic. The general.zed extreme values distribution(GEV) was selected to model the maximum daily rainfall of 10 groups located in the north of the steppe region and the general.zed logistic distribution(GLO) for groups representing the steppes of Central.and Western Algeria. The study of uncertainty by the bias and RMSE showed that the regional approach is acceptable. We have also developed maximum daily rainfall maps for 2, 5, 10, 20, 50 and 100 years return periods. We relied on a network of 255 rainfall stations. The spatial variability of quantiles was evaluated by semi-variograms. All rainfall frequency models have a spatial dependence with an exponential model adjusted to the experimental semi-variograms. The parameters of the fitted semi-variogram for different return periods are similar, throughout, while the nugget is more important for high return periods. Maximum daily rainfall increases from South to North and from West to East, and is more significant in the coastal areas of ea

关键词： Annual maximum daily rainfall Regionalisation L-moments Mapping Northern Algeria

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

Reduced Sensitivity of Tropical Cyclone Intensity and Size to Sea Surface Temperature in a Radiative-Convective Equilibrium Environment

引用

Advances in Atmospheric Sciences 2018年第8期35卷 85-97页

作者： Shuai WANG ral. toumi State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography Space and Atmospheric Physics Group Department of PhysicsImperial College London

It has been challenging to project the tropical cyclone （TC） intensity, structure and destructive potential changes in a warming climate. Here, we compare the sensitivities of TC intensity, size and destructive potential to sea surface warming with and without a pre-storm atmospheric adjustment to an idealized state of Radiative-Convective Equilibrium （RCE）. Without RCE, we find large responses of TC intensity, size and destructive potential to sea surface temperature （SST） changes, which is in line with some previous studies. However, in an environment under RCE, the TC size is almost insensitive to SST changes, and the sensitivity of intensity is also much reduced to 3% ~C-1-4% ~C-1. Without the pre-storm RCE adjustment, the mean destructive potential measured by the integrated power dissipation increases by about 25% ~C-1 during the mature stage. However, in an environment under RCE, the sensitivity of destructive potential to sea surface warming does not change significantly. Further analyses show that the reduced response of TC intensity and size to sea surface warming under RCE can be explained by the reduced thermodynamic disequilibrium between the air boundary layer and the sea surface due to the RCE adjustment. When conducting regional-scale sea surface warming experiments for TC case studies, without any RCE adjustment the TC response is likely to be unrealistically exaggerated. The TC intensity-temperature sensitivity under RCE is very similar to those found in coupled climate model simulations. This suggests global mean intensity projections under climate change can be understood in terms of a thermodynamic response to temperature with only a minor contribution from any changes in large-scale dynamics.

关键词： tropical cyclone sea surface temperature radiative-convective equilibrium intensity size destructive potential

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

SIMPLE PROOFS OF THE CAUCHY-SCHWARTZ INEQUALITY AND THE NEGATIVE DISCRIMINANT PROPERTY IN ARCHIMEDEAN ALMOST f-ALGEBRAS

引用

Analysis in Theory and Applications 2009年第2期25卷 117-124页

作者： Adel toumi Mohamed Ali toumi Nedra toumi Laboratoire de Physique des Liquides Critiques Département de Physique Faculté des Sciences de Bizerte 7021 Zarzouna Bizerte Tunisia Département des Mathématiques Faculté des Sciences de Bizerte 7021 Zarzouna Bizerte Tunisia

The paper presents simple proofs of the Cauchy-Schwartz inequality and the negative discriminant property in archimedean almost f-algebras^[5], based on a sequence approximation.

关键词： Cauchy-Schwartz inequality f-algebra almost f-algebra positive square g-algebra

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

Complex Interpolation of Weighted Besov and Lizorkin–Triebel Spaces

引用

Acta Mathematica Sinica,English Series 2014年第8期30卷 1297-1323页

作者： Winfried SICKEL Leszek SKRZYPCZAK Jan VYBíral Friedrich-Schiller-Universitt Jena Mathematisches InstitutErnst-Abbe-Platz 207743 JenaGermany Adam Mickiewicz University Poznan Faculty of Mathematics and Computer ScienceUl.Umultowska 8761-614 PoznańPoland Technical University Berlin Department of MathematicsSecretary office MA 4-1Street of 17.June 13610623 BerlinGermany

We study complex interpolation of weighted Besov and Lizorkin–Triebel *** used weights w0,w1 are local Muckenhoupt weights in the sense of *** a first step we calculate the Calder′on products of associated sequence ***,as a corollary of these investigations,we obtain results on complex interpolation of radial subspaces of Besov and Lizorkin–Triebel spaces on Rd.

关键词： Muckenhoupt weights local Muckenhoupt weights weighted Besov and Lizorkin-Triebel spaces radial subspaces of Besov and Lizorkin-Triebel spaces complex interpolation Calderon products

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

Lightning activity on the central.Tibetan Plateau and its response to convective available potential energy

引用

Chinese Science Bulletin 2003年第3期48卷 296-299页

作者： QIEXiushu R.toumi 等 ColdandAridRegionsEnvironmentalandEngineeringResearchInstitute.ChineseAcademyofSciences Lanzhou730000China ColdandAridRegionsEnvironmentalandEngineeringResearchInstitute.ChineseAcademyofSciences Lanz

Lightning flash activities on the central.Tibetan Plateau have been studied by using the satellite-based Light-ning Imaging Sensor (LIS) database from January 1998 to July 2002. The lightning activity shows a clear diurnal varia-tion on the central.Plateau. The peak lightning activity ap-pears at about 17︰00 which is 3 h earlier than that in Jing-zhou, Hubei in the same latitude belt nearby, indicating that the lightning activity is a sensitive indicator of solar heating on the Plateau. The lightning discharge is weaker on the Plateau than Jingzhou, Hubei and other low-altitude conti-nental regions because of the lower convective available po-tential energy (CAPE) on the Plateau. The CAPE on the Plateau is 12 times lower than that in Jingzhou, Hubei, and 20 times lower than that in the sea-level region, such as Guangzhou and Florida. However, the sensitivity of lightning activity to CAPE changes on the Plateau is up to 30 times more sensitive than other prominent low-altitude regions.

关键词：青藏高原中部闪电活动对流性电势能卫星图片气候资料

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

Existence and Global Asymptotic Behavior of Positive Solutions for Sublinear and Superlinear Fractional Boundary Value Problems

引用

Chinese Annals of Mathematics,Series B 2016年第1期37卷 1-28页

作者： Imed BACHAR Habib MAAGLI Faten toumi Zagharide ZINE EL ABIDINE Mathematics Department College of Science King Saud University P.O.Box 2455 Riyadh 11451 Saudi Arabia. Department of Mathematics College of Sciences and Arts Rabigh Campus King Abdulaz University P.O.Box 344 Rabigh 21911 Saudi Arabia. Departement de Mathematiques Faculte des Sciences de Tunis Campus Universitalre 2092 Tunis Tunisia.

In this paper, the authors aim at proving two existence results of fractional differential boundary value problems of the form （Pa,bα）{D^au（x）＋f（x,u（x））=0,x∈（0,1）,u（0）=u（1）=0,D^a-3u（0）=a,u^（1）=-6where 3 ≤ a 〈 4, D^ is the standard Riemann-Liouville fractional derivative and a, b are nonnegative constants. First the authors suppose that f（x, t） = -p（x）t^σ, with cr ~ （-1, 1） and p being a nonnegative continuous function that may be singular at x - 0 or x - 1 and satisfies some conditions related to the Karamata regular variation theory. Combining sharp estimates on some potential functions and the Sch^uder fixed point theorem, the authors prove the existence of a unique positive continuous solution to problem （P0,0）. Global estimates on such a solution are also obtained. To state the second existence result, the authors assume that a, b are nonnegative constants such that a ＋ b 〉 0 and f（x, t） -= tφ（x, t）, with φ（x, t） being a nonnegative continuous function in （0, 1） × [0, ∞） that is required to satisfy some suitable integrability condition. Using estimates on the Green＇s function and a perturbation argument, the authors prove the existence and uniqueness of a positive continuous solution u to problem （Pa,b）, which behaves like the unique solution of the homogeneous problem corresponding the existence results. to （Pa,b）. Some examples are given to illustrate the existence results.,

关键词： Fractional differential equation Positive solution Fractional Green's function Karamata function Perturbation arguments Sch/iuder fixad point theorem

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

Importance of Air-Sea Coupling in Simulating Tropical Cyclone Intensity at Landfall

引用

Advances in Atmospheric Sciences 2022年第10期39卷 1777-1786页

作者： Charlie C.F.LOK Johnny C.L.CHAN ral. toumi School of Energy and Environment City University of Hong KongHong KongChina Department of Physics Imperial CollegeLondon SW72AZUK

An atmosphere-only model system for making seasonal prediction and projecting future intensities of landfalling tropical cyclones(TCs)along the South China coast is upgraded by including ocean and wave models.A total of 642 TCs have been re-simulated using the new system to produce a climatology of TC intensity in the South China *** comparisons of the simulations from the atmosphere-only and the fully coupled systems reveal that the inclusion of the additional ocean and wave models enable differential sea surface temperature responses to various TC characteristics such as translational speed and *** particular,interaction with the ocean does not necessarily imply a weakening of the TC,with the coastal bathymetry possibly playing a role in causing a near-shore intensification of the *** results suggest that to simulate the evolution of TC structure more accurately,it is essential to use an air-sea coupled model instead of an atmosphere-only model.

关键词： tropical cyclone intensity tropical cyclone landfall seasonal prediction air-sea coupling

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

Synergistic combination of colistin with imipenem, amikacineor ciprofloxacin against Acinetobacter baumannii andPseudomonas aeruginosa carbapenem-resistant isolated inAnnaba hospital Algeria

引用

BIOCELL 2020年第2期44卷 175-182页

作者： SAIDA MELIANI SOUMAYA toumi HEYTHEM DJAHOUDI KHALED DEGHDEGH KAMEL AMOURA ABDELGHANI DJAHOUDI Department of Biochemistry Faculty of SciencesLaboratory of MicrobiologyBadji Mokhtar UniversityAnnabaAlgeria Department of Biochemistry Eco-biology Laboratory for Marine and Coastal AreasFaculty of SciencesBP 12 El-HadjarBadjiMokhtar UniversityAnnabaAlgeria Faculty of Medicine Pulmonology Service Badji Mokhtar UniversityAnnabaAlgeria Faculty of Medicine CHU AnnabaBadji Mokhtar UniversityAnnabaAlgeria Department of Pharmacy Faculty of MedicineLaboratory of MicrobiologyBadji Mokhtar UniversityAnnabaBP 205Algeria

Objective:The aim of this study is to detect in vitro the synergetic activity of colistin in combination with imipenem,amikacin or ciprofloxacin,at sub-inhibitory concentrations,against carbapenems-resistant(CR)Acinetobacter baumannii and Pseudomonas aeruginosa strains isolated from various wards in Annaba teaching hospital in eastern *** and Methods:The minimal inhibitory concentrations(MIC)were determined by broth macrodilution(BMD).Carbapenemase encoding genes were screened using polymerase chain reaction(PCR).The activity of colistin in combination with second antibiotic was evaluated by the Checkerboard ***:39 CR *** and 21 CR *** strains where *** MIC values ranging from(0.25 to 4μg/ml)to colistin,≥16μg/ml for imipenem,≥4μg/ml to amikacin and≥8μg/ml *** PCR reveals the presence of the genes blaOXA23(n=12),blaOXA24(n=6),blaNDM1(n=3)in *** and blaVIM2(n=12)in *** combination of colistin with imipenem showed synergistic effect on 57.14%and 46.15%of *** and *** isolates,*** colistin and amikacin,the synergistic effect is detected in 28.6%of *** and 30.8%of *** colistin and ciprofloxacin showed synergy on 14.29%and 15.38%of *** and *** isolates,***:CR *** and *** remain the most prevalent infection agents in patients from high-risk wards at Annaba *** associated with imipenem or with amikacin at sub-inhibitory concentrations gives very encouraging results allowing better management of infections caused by this type of bacteria.

关键词： Carbapenemases Colistin Combination GNB-NF Sub-inhibitory concentration

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

Thermoluminescent response of gamma irradiated Na^(+)–Cu^(+) ionexchanged silicate glass in large dose range

引用

Nuclear Science and Techniques 2023年第5期34卷 22-32页

作者： Safa toumi Khaled Farah Laboratoire de Physico‑Chimie des Matériaux Département de PhysiqueFacultédes Sciences de MonastirUniversitéde MonastirMonastirTunisia Institut Supérieur du Transport et de la Logistique de Sousse Universitéde Sousse4023 SousseTunisia Laboratoire de Recherche en Energie et Matière Développement des Sciences Nucléaires(LR16CNSTN02)Centre National des Sciences et Technologies Nucléaires2020 Sidi‑ThabetTunisia

The introduction of metals into vitreous matrices is the origin of various interesting phenomena;in particular,the presence of copper ions in glass has been the subject of considerable research because of its numerous *** ion-exchange process is primarily used to introduce copper ions into glass *** thermoluminescence(TL)of silicate glass was studied to evaluate its potential as gamma-sensitive material for dosimetric applications;the effect of copper doping on the thermoluminescent sensitivity was investigated using the Cu-Na ion-exchange technique for different concentrations and doping conditions,over a wide dose range of 10 mGy to 100 *** results showed that Cu doping significantly improved the sensitivity of the glasses to gamma *** the ion-exchange,two peaks appeared in the glow curves at approximately 175 and 230°C,respectively,which possibly originated from the Cu^(+) centers,along with a weak TL peak at around 320℃.We also attempted to explain the origin of the observed thermoluminescence by exploiting the Electron paramagnetic resonance(EPR)*** results clearly show quenching of the TL emission with increasing copper *** present work indicates that the thermoluminescence response of these glasses to gamma rays can be reasonably measured in the range of 0.001-100 *** study also facilitates the understanding of the basic TL mechanism in this glass system.

关键词： Cu-Na ion-exchange Silicate glass Thermoluminescence Gamma irradiation Electron paramagnetic resonance

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：