Characterization of mean stem density,fibre length and lignin from two Acacia species and their hybrid

The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz.Acacia mangium Willd.and Acacia auriculiformis A.Cunn.Ex Benth.and their hybrid.Acid insoluble lignin content(Klason),mean stem density and fibre length differed considerably among the species and hybrids.A.mangium possessed a high percent of lignin content compared to A.auriculiformis and the Acacia hybrid.However,mean stem density of A.auriculiformis was higher than A.mangium and the hybrid.Fibre length of heartwood tissues was generally shorter than that of sapwood tissues.The hybrid had longer fibres than the parent species.Lignin was negatively correlated with mean stem density.Generally,the wood properties of the hybrid were superior to its parent species.The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species.Considering thedifficulty involved in accurately measuring the lignin content compared to mean stem density,selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.

THE SYSTEMS WITH ALMOST BANACH-MEAN EQUICONTINUITY FOR ABELIAN GROUP ACTIONS

In this paper,we present the concept of Banach-mean equicontinuity and prove that the Banach-,Weyl-and Besicovitch-mean equicontinuities of a dynamic system of Abelian group action are equivalent.Furthermore,we obtain that the topological entropy of a transitive,almost Banach-mean equicontinuous dynamical system of Abelian group action is zero.As an application of our main result,we show that the topological entropy of the Banach-mean equicontinuous system under the action of an Abelian groups is zero.

Efficiency of Slit Dam Prevention against Non-Viscous Debris Flow

This paper describes an experimental work in order to assess the efficiency of slit dam on non-viscous debris flow. Some results have been acquired as follows： （1） there are three kinds of blocking type; Total-blocking, opening and part-blocking. The blocking conditions of slit dam are closely link to b/dmax （the ratio of slit width to maximum diameter of solid matter）, as b/dmax is less than 0. 739, the slit dam is total- blocking; and b/dmax is more than 1. 478, the slit dam will be opening; whereas b/dma ranges from 0. 739 to 1. 478, the slit dam is part-blocking. （2） Variation of the mean density passing through slit dam is the most obvious as b/dmax ranges from 0. 739 to 1. 232. （2） According to experimental results, slit dams have been shown to be effective in reducing debris flow density while slit density ∑ b/B （B is slit dam width） ranges from 0.2 to 0. 5.

Forest Carbon Storage and Tree Carbon Pool Dynamics under Natural Forest Protection Program in Northeastern China

The Natural Forest Protection(NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting and restoring the structures and functions of the natural forests through sustainable forest management. However, the role of forest carbon storage and tree carbon pool dynamics since the adoption of the NFP remains unknown. To address this knowledge gap, this study calculated forest carbon storage(tree, understory, forest floor and soil) in the forest region of northeastern(NE) China based on National Forest Inventory databases and field investigated databases. For tree biomass, this study utilized an improved method for biomass estimation that converts timber volume to total forest biomass; while for understory, forest floor and soil carbon storage, this study utilized forest type-specific mean carbon densities multiplied by their areas in the region. Results showed that the tree carbon pool under the NFP in NE China functioned as a carbon sink from 1998 to 2008, with an increase of 6.3 Tg C/yr, which was mainly sequestrated by natural forests(5.1 Tg C/yr). At the same time, plantations also acted as a carbon sink, reflecting an increase of 1.2 Tg C/yr. In 2008, total carbon storage in forests covered by the NFP in NE China was 4603.8 Tg C, of which 4393.3 Tg C was stored in natural forests and 210.5 Tg C in planted forests. Soil was the largest carbon storage component, contributing 69.5%–77.8% of total carbon storage; followed by tree and forest floor, accounting for 16.3%–23.0% and 5.0%–6.5% of total carbon storage, respectively. Understory carbon pool ranged from 1.9 to 42.7 Tg C, accounting for only 0.9% of total carbon storage.

Prevalence and risk factors associated with malaria infection among pregnant women in a semi-urban community of north-western Nigeria

Background:Malaria during pregnancy remains a serious public health problem,with substantial risks for the mother,her foetus and the newborn.The aim of this study was to determine the prevalence of malaria and possible risk factors for malaria infection among pregnant women in a semi-urban area in north-western Nigeria.Pregnant women are among the most susceptible to malaria infection.Knowledge of their malaria infection status is an important yardstick to measure the effectiveness of any malaria control programme.Methods:We conducted a cross sectional study in the semi-urban area of Argungu,Kebbi State Nigeria.Two hundred and fifty five pregnant women were included in the study after informed verbal consent was obtained.For each participant,the socio-demographic profile,stage of pregnancy and attitude to the use of insecticide-treated nets(ITNs)were investigated using a questionnaire.Peripheral blood samples were collected and thick blood smears were prepared and stained with Giemsa stains to check for malaria parasitaemia.The associations between age,education level and use of ITNs with occurrence of malaria infection during pregnancy were analysed using the chi-square test.Results:One hundred and six(41.6%)out of 255 pregnant women were infected with malaria parasites,with a mean parasite density of 800 parasitesμl−1.It was found that prevalence and parasite density decreased as age increased.The chi-square test indicated that a lack of education and non-usage of ITNs were significantly associated with malaria infection.Conclusion:Malaria is still a major public health issue among pregnant women mainly due to illiteracy and non-compliance to using ITNs.Increasing awareness about malaria preventive measures and early attendance of antenatal care services will help to reduce malaria and,consequently,its associated morbidities and mortalities.