Oldest Asian Record of Snapping Shrimps (Malacostraca: Alpheidae) from the Kutch Basin, Western India and Associated Biota: Biostratigraphic, Paleoenvironmental and Paleoecological Significance

The oldest Asian record of alpheid shrimps, assigned to genus Alpheus, based on snapping claw fingertips from the Miocene Khari Nadi Formation in the Kutch Basin, western India reported herein, extends the fossil record of the family Alpheidae from Asia by ~22 million years. An early Miocene (Aquitanian) age is estimated based on the associated assemblage of calcareous nannofossils, Sphenolithus disbelemnos, Cyclicargolithus floridanus, and Reticulofenestra haqii. The co-occurring microbiota includes bony fish otolith remains, identified as “genus Gobiidarum”, isolated teeth of Dasyatis rays, Sphyrna sharks, and teleosts, ctenoid and placoid scales, ostracods, belonging to the genera Paractinocythereis, Alocopocythere, Ruggieria? Aglaiocypris, Bairdoppilata, and echinoid spines. Taken together, the microfossil assemblage and data from chemical analyses using Energy Dispersive Spectroscopy, X-Ray Diffraction and Wavelength Dispersive X-Ray Fluorescence of host and associated lithologies suggests prevalence of a shallow (neritic) to coastal marine (intertidal) depositional paleoenvironment.     

AN EVALUATION OF ACTUAL EVAPOTRANSPIRATION IN TROPICAL EAST AFRICA

Monthly actual evapotranspiration (AET) for four humid catchments in Kenya, East Africa was evaluated using the Morton and Grindley models. The area of each catchment was less then 100 km² and all catchments lie around the equator. Three of the catchments are chiefly vegetated with pasture, annual and perennial crops, whereas one is largely under forest. The AET estimates from the aforementioned models were compared with those based on a water balance analysis. A total of 34 data years for daily rainfall and run off for all the catchments were used for analysis. The results indicated that both models tended to overestimate AET in relation to the water balance-based values. The Grindley model (AET_G) overestimated such that the estimates were either equal or close to the Penman potential evapotranspiration (PET) values in all the catchments. The Morton model (AET_M) performed better, and AET estimates by this method, although marginally higher, were closer to the water balance-based estimates. The overall overprediction by the Grindley model on a monthly basis was of the order of 32% whereas by the Morton model it was only 8%. Although the mean values from the Morton model are only 8% higher than the water balance values on a monthly basis, values of the RMSE (root mean square error) range between 25 and 47 mm. The additional merit of the Morton model lies in its ability to provide estimates of AET based solely on meteorological data, which are readily available in Kenya, East Africa. © 1997 by John Wiley & Sons, Ltd.     

尼泊尔Andhi Khola河研究参照点的识别及确认

参照条件是开展河流生态学研究的基础,这些条件不受或很少受到人为干扰。为研究尼泊尔Andhi Khola河上一处河坝的生态影响,采用野外快速生物筛分（RFB）法预先划分出2个研究参照点或最少干扰参照点,于2013年1月和2月采集了生物学样品（大型脊椎动物）和物理-化学样品。对大型无脊椎动物区系使用多栖息地采样（MHS）法。通过一些指标对预选的研究点进行了确认,这些指标是：尼泊尔生物评价法（NEPBIOS）、生物监测评价法（BMWP）、兴都库什喜马拉雅生物评价法（HKHBIOS）、Hilsenhoff法（HILSENHOFF）,以及国家卫生基金会水质指标法（NSFWQI）。NEPBIOS、HKHBIOS、HILSENHOFF、RFB以及NSFWQI指标预测2个参照点的河水水质都比较好,达到II级水准。只有BMWP/ASPT水质指标预测2个参照点的河水水质都很好,达到I级水准。如此,预选的这2个水质较好的点（II级）被确认为研究参照点。本研究表明,多度量法适用于即将修建水利工程的河流的监测与评价。     

A drought frequency formula

Abstract

The important elements of a drought phenomenon are the longest duration and the largest severity for a desired return period. These elements form a basis for designing water storage systems to cope with droughts. At times, a third element, drought intensity, is also used and is defined as the ratio of severity to duration. The commonly available statistics for the causative drought variables such as annual rainfall or runoff sequences are the mean, the coefficient of variation and the lag one serial correlation coefficient, and occasionally some indication of the probability distribution function (pdf) of the sequences. The extremal values of the duration and severity are modelled in the present paper using information on the aforesaid parameters at the truncation level equal to the mean of the drought sequence, which is generally taken as the truncation level in the analysis of droughts. The drought severity has been modelled as the product of the duration and intensity with the assumption of independence between them. An estimate of drought intensity has been realized from the concept of the truncated normal distribution of the standardized form of the drought sequences in the normalized domain. A formula in terms of the extremal severity and the T-year return period has been suggested similar to the flood frequency formulae, commonly cited in hydrological texts.     

Flash flood of July 1979 in the Luni basin—a rare event in the Indian desert

ABSTRACT

A well marked low pressure monsoon depression caused unprecedented heavy rainfall of five days duration (15–19 July 1979) in the Luni basin in the India arid zone. It caused the worst flash flood in living memory. Saturated antecedent soil moisture conditions, thin soil cover underlain by bed rock or hardpan, a larger area of exposed rocks in the basin and failure of the earthen reservoirs further worsened the flood effect. During flooding, suspended sediment concentrations rose from 0.86 to 40.2 g 1^?1 downstream due to bank scouring, erosion and high transmission losses of the runoff volume in the alluvial channels. The dilution effect of flooding caused lower concentrations of the total dissolved solids which increased with downstream travel. Social effects of this flood and consequences on future planning in the Luni basin have also been discussed.     

QUANTITATIVE ANALYSIS OF TRACE ELEMENTS IN GEOLOGICAL MATERIALS BY LASER ABLATION ICPMS: INSTRUMENTAL OPERATING CONDITIONS AND CALIBRATION VALUES OF NIST GLASSES

A UV laser ablation microprobe coupled to an ICPMS has been used to determine trace element concentrations in solids with a spatial resolution of 50 microns and detection limits ranging from 2 μg/g for Ni to 50 ng/g for the REE, The, and U. Experiments designed to optimize laser operating conditions show that pulse rates of 4 Hz produce a steady state signal with less inter-element fractionation per unit time than higher pulse rates (10–20 Hz). Comparisons of laser microprobe analyses of garnets and pyroxenes using the NIST 610 and 612 glasses as calibration standards, with proton microprobe, solution ICPMS, INAA and XRF data show no significant matrix effects. Laser microprobe analyses of the NIST 610 and 612 glasses have a precision and accuracy of 2–5%, and error analysis shows that counting statistics and the precision on the internal standard concentration accounts for the analytical uncertainty. The NIST glasses appear to be useful calibration materials for trace element analysis of geological materials by laser microprobe.     

BICUBIC SPLINE INTERPOLATION: A QUANTITATIVE TEST OF ACCURACY AND EFFICIENCY*

Two different methods for the construction of an approximation to bicubic splines for interpolating irregularly spaced two-dimensional data are described. These are referred to as the least squares line (LSL) and linear segment (LINSEG) construction procedures. A quantitative test is devised for investigating the absolute accuracy and efficiency of the two spline interpolation procedures. The test involves (i) laying of artificial flight lines on the analytically known field of a model, (ii) interpolation of field values along the flight lines and their subtraction from the original field values to compute the residuals. This test is applied on fields due to four models (three prism models and one dyke model) placed at different depths below the flight lines, and for each case the error estimates (the mean error, the maximum error and the standard deviation) are tabulated. An analysis of the error estimates shows in all cases the LSL interpolation to be more accurate than the LINSEG, although the latter is about 50% faster in computer time. The relative accuracy and efficiency of the LSL interpolation is also tested against a recent method based on harmonization procedure, which shows the latter to be more precise, though much slower in speed.