孙陶然与他的拉卡拉

“给老爸老妈送了一个拉卡拉，老爸老妈很快就自己完成安装并学会使用，他们还告诉我：特别方便、实用!这下很多交费跑腿的麻烦都省啦!”这是前段时间著名体育评论员黄健翔在微博上发的一条小段子。结果却被人认为是在帮人做广告，黄健翔索性又发了几条微博，强调这个东西的确很有用。

The Origin of Tar AI-Say＇ed and Tar AI-Najaf, Karbala-Najaf Vicinity, Central Iraq

In central part of Iraq within the vicinity of Karbala-Najaf, two cliffs called ＂Tar Al-Say＇ed＂ and ＂Tar Al-Najaf＂ form conspicuous geomorphological forms between the Mesopotamia Plain and the Western and Southern Deserts. The top surface between the two cliffs （tars） is covered by alluvial fan sediments, laid down by A1-Khir Valley when merging in a large depression due to the drop in the gradient of the valley. Consequently, the depression was divided into two parts, to the left is called Al-Razzazah Depression, whereas to the right is called Bahir Al-Najaf. This affected the course of the River Euphrates. The deposition stopped due to an uplift movement which caused the elevation of the two cliffs which are covered by alluvial fan sediments. The two cliffs had and are still suffering from retreating, due to lateral erosion by wave actions in Al-Razzazah Depression. Springs located along a straight line, sag pond, deflected drainage, shutter ridges and pressure ridges can be noticed in the area. The age of both cliffs is estimated to be upper Late Pleistocene--early Holocene.

Morphotaxonomy and seasonal distribution of planktonic and benthic Prorocentrales in Karachi waters,Pakistan Northern Arabian Sea

Morphotaxonomy and seasonal abundance of dinoflagellates of the genera Prorocentrum and Mesoporos （Prorocentrales） were studied from nutrient-rich waters, Karachi Harbor and the mouth of the Manora Channel, Pakistan during May 2002-July 2003. Using both light and scanning electron microscopy, 13 species of Prorocentrales were identified according to cell shape, size, ornamentation of thecal plates, and architecture of apical platelets, apical pore area, marginal pores, and intercalary bands. P. sigmoides, P. arcuatum, P. scutellum, P. donghaiense, P. balticum, P. minimum, P. emarginatum, P. lima, P. faustiae, and Mesoporos perforatus constitute new records for sindh coast of Pakistan. The most abundant species were P. minimum/P, balticum （4.5x103 cells/L）, P. micans （1.1~103 cells/L）, P. gracile/P, sigmoides （2.5 x 102 cells/L） and P. donghaiense （6.6 x 103 cells/L） at temperatures of 29-31 ~C and salinities of 35-40. Maximum abundance was observed in winter and lower abundance in summer. There was no significant change in the distribution of species between stations except for the benthic species which occurred close to Karachi Harbor waters. Significant positive correlations were observed between Prorocentrum spp. and temperature （R2=0.27） and negative correlations with salinity （R2=-0.32） except for P. minimum and P. emarginatum which has negative correlation with temperature （R2=-0.24） and positive with salinity （R2=0.08, 0.19）. The finding of potential okadaic-acid producing species of benthic Prorocentrum call for monitoring for possible human health problems in this region.

Interactions of carrageenan or its degradation product with R15K by affinity capillary electrophoresis

V3 loop of HIV-1 envelop protein gp120 plays a pivotal role in the entry process of HIV-1 into target cells. R15K, the relatively conserved region of V3 loop, can be used in binding studies instead of recombinant gp120 molecule. Polyanionic compounds, such as carrageenan, possess antiviral activity through disrupting gp120-CD4 interaction, and chemical modifications have been performed to improve such activity. In this work, we, for the first time, analyzed the interactions between carrageenan or its degradation and R15K by affinity capillary electrophoresis （ACE）. Our results revealed that depolymerized carrageenan rather than carrageenan could bind to R15K. The binding constant of depolymerized carrageenan was （2.94±0.57）× 10^6 mol/L. Our finding indicated that the depolymerized carrageenan could be R15K antagonist, and it might inhibit the infection of HIV-1 through the entry process.

Satellite Image-based Monitoring of Urban Land Use Change and Assessing the Driving Factors in Pokhara and Bharatpur Metropolitan Cities, Gandaki Basin, Nepal

Urban growth is a key indicator of economic development.At the same time,haphazard urban growth creates serious socioeconomic,environmental and urban land management problems.In this context,understanding the process of urban landscape change is important for guiding the sustainable growth of urban areas.This study analyzes the urban land changes during 1990–2018 in two metropolitan cities of Gandaki basin:Pokhara and Bharatpur.Landsat satellite images were analyzed using supervised classification methods.The results revealed that the built-up area has increased significantly by 300%in Pokhara and by nearly 500%in the Bharatpur during the past 28 years.Population growth,migration from surrounding areas due to urban facilities and the easy lifestyle in cities were found to be major determinants of urban growth within the study area.In addition,the changing urban definition and expansion of municipal boundaries are key factors for rapid urban growth.Both cities are likely to grow in the future as they are both located in areas that encompass the high levels of commercial activity and modern service facilities.The haphazard urban growth should be minimized through planning and policies for sustainable urban development.