Employing nature to combat floods: some experiences from Malaysia

Natural undisturbed systems possess inherent mechanisms and their own ways and means of maintaining system stability. Forests and floodplains, also commonly known as wetlands, are nature's way of controlling floods. Forests and wetland forests control floods by controlling rainfall at source, a concept only recently adopted by flood control agencies. Layered and densely forested areas intercept a significant amount of rainfall and regulate the flow of rain down branches, trunks and roots before reaching the river. Interception, the amount of rainfall caught in the forest crown, is about 10 - 15% of total rainfall. Least interception occurs when forests are thinned and exposed due to clearing, while maximum interception (often reaching 100 %) occurs with dense virgin forests made up of evergreen trees. During heavy rainstorms, rainwater commences to drift as mists or droplets to earth as "throughfall" which averages about 75 - 85% of rain in humid climates like Malaysia. Runoff from upstream also has to penetrate the forest before reaching the river, hence increasing lead time. Wetland forests along rivers, estuaries and coastal areas also give runoff from precipitation (which eventually gets into rivers) a place to spread out, serving as natural retention basins. Wetland forests act like sponges soaking and absorbing a lot of water down into the ground and then releasing it slowly over time. As much as 2.3 million litres of water is absorbed per hectare, depending on the nature of the soil. Forests hold the water and release it slowly. When forests are cleared or destroyed, all the rainwater gets into rivers at a relatively rapid time, resulting in flash floods. The concentration of water into the main river channel over a much shorter period of time dramatically increases flooding. It is vital for engineers and all scientists to work with natural systems rather than against them. In this respect, the JPS Malaysia has initiated the mandatory Manual for Environmentally Friendly Drainage for all development projects, indicating an all-important change of mindset from conventional engineering approach to a more comprehensive multi¬disciplinary approach that taps on the expertise of all disciplines

Predicting Raccoon, Procyon lotor, Occurrence Through the Use of Microhabitat Variables

Recent increases in Raccoon (Procyon lotor) abundance have been implicated for decreased nesting success of songbirds and transmission of rabies. Understanding the relationship between occurrence and microhabitat factors should be helpful in managing this species, though our current understanding of this relationship is inadequate. Therefore, we conducted a study in western Tennessee during 2000–2002 to determine this association. Occurrence (capture) data were assessed from results of live trapping at 176 and 112 trap sites during winter and summer, respectively, at three sites. A maximum of 26 habitat variables were measured at each trap location; all grids were combined for statistical analyses to account for varying relationships between occurrence and microhabitat factors across different landscapes. Univariate and stepwise logistic-regression analyses were used to assess associations among microhabitat variables and occurrence. Resulting models were validated through the jackknife procedure. Predictive equations were constructed from logistic-regression models to compute capture probabilities. Univariate analyses yielded numerous significant variables with those representing forest characteristics and proximity to water generally the most significant. Strong concordance was observed between winter and summer seasons for most variables though several differed (number of large hardwood snags, ground dens, and plant food species, distance to potential water and roads). Such temporal variability was expected due to seasonal differences in habitat components and biological needs of Raccoons. Variables included in derived models were similar to those scoring highest in univariate analyses; classification rates for models (winter = 72%; summer = 78%) were among the highest recorded for generalist species. By accounting for landscape attributes and replicating across sites, more accurate and useful models were developed. Such models should provide the information required to effectively manage this species

A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

We established a method on measuring the \dzdzb mixing parameter $y$ for BESIII experiment at the BEPCII $e^+e^-$ collider. In this method, the doubly tagged $\psi(3770) \to D^0 \overline{D^0}$ events, with one $D$ decays to CP-eigenstates and the other $D$ decays semileptonically, are used to reconstruct the signals. Since this analysis requires good $e/\pi$ separation, a likelihood approach, which combines the $dE/dx$, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of $y$ to be 0.007 based on a $20fb^{-1}$ fully simulated MC sample.Comment: 6 pages, 7 figure

Descope of the ALIA mission

The present work reports on a feasibility study commissioned by the Chinese Academy of Sciences of China to explore various possible mission options to detect gravitational waves in space alternative to that of the eLISA/LISA mission concept. Based on the relative merits assigned to science and technological viability, a few representative mission options descoped from the ALIA mission are considered. A semi-analytic Monte Carlo simulation is carried out to understand the cosmic black hole merger histories starting from intermediate mass black holes at high redshift as well as the possible scientific merits of the mission options considered in probing the light seed black holes and their coevolution with galaxies in early Universe. The study indicates that, by choosing the armlength of the interferometer to be three million kilometers and shifting the sensitivity floor to around one-hundredth Hz, together with a very moderate improvement on the position noise budget, there are certain mission options capable of exploring light seed, intermediate mass black hole binaries at high redshift that are not readily accessible to eLISA/LISA, and yet the technological requirements seem to within reach in the next few decades for China

Management of flood disasters in the Jianghan Plain, China

This study examines the causes of flood disasters in Jianghan Plain, China and provides practical solutions to mitigate them. Results from this study indicate that both historical archives and more recent recorded data point to an increasing frequency in flood disasters since 1961. Furthermore, damage and losses from flood disasters have also increased significantly in the region. By analyzing the physical geographic factors and human activities, this study found that the main causative factors contributingto increasingflood disasters are landform/topography, climate elements, reduced drainage capacity of rivers in contrast to increased flood discharge, and human activities. Finally, the study examines various practical solutions to mitigate flood disasters in the Jianghan Plain. © MCB University Press

An assessment of microhabitat variables and capture success of striped skunks (Mephitis mephitis)

The association of microhabitat variables and capture (= occurrence) of striped skunks (Mephitis mephitis) was assessed at 3 sites in western Tennessee. Sixteen features were included in univariate and stepwise logistic regressions to investigate relationships between occurrence and habitat factors and to construct models predictive of occurrence. Accuracy of models was examined using jackknife procedures, and maps predictive of occurrence were developed through semivariance and kriging analyses. Average height of stand, hardwood snags \u3e35 cm diameter at breast height, number of stems, distance to permanent water sources, and distance to open areas were among the habitat features most frequently found to be related to occurrence. Models derived from logistic regression predicted occurrence of the species at varying levels (56% to 75%). Overall, classification percentages appeared to be at a level useful for predicting the occurrence of M. mephitis, and mapping procedures sufficient for illustrating the association between occurrence and habitat