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41.
42.
Baruah M Das M Sengupta S 《Journal of environmental biology / Academy of Environmental Biology, India》2001,22(4):315-317
The food and feeding behaviour of Amphiesma stolatum was studied. A total of 117 snakes were examined to analyse the diet composition. Ten live snakes were maintained in enclosure for evaluating the feeding habit, choice of food and rate of assimilation. The anurans constituted the major diet of the food spectrum. In captivity, fishes (fry), amphibians and reptiles were consumed by the snakes. A. stolatum exihibited Elaphe type of hunting behaviour. In most cases the snake struck the prey at its head. The assimilation rate with frog was highest. 相似文献
43.
Maiti SK Das PK Ray SK 《Journal of environmental biology / Academy of Environmental Biology, India》2003,24(4):465-470
Chronic fluoride toxicity in the form of dental fluorosis was observed in cattle from nine (9) villages under two (2) blocks of Nayagarh district of Orissa. Out of 1117 cattle, 221 (18.09%) showed the signs of dental fluorosis. In all affected villages, the prevalence of dental fluorosis in calves (< 1 year age) was greater than adults. There was significant difference in prevalence in respect to age. The commonly observed signs of dental fluorosis were brown discoloration, mottling, attrition or uneven wearing of teeth with or without pitting. None of the affected animals showed characteristic signs of osteofluorosis. The mean serum and urine fluoride concentration of affected animals were significantly (P < 0.05) higher than those of control animals. Fluoride levels (mean) of ground water and surface water in two blocks were 1.30 +/- 0.16 ppm, 0. 66 +/- 0.08 ppm and 1.12 +/- 0.19 ppm, 0. 48 +/- 0.05 ppm respectively. The fluoride content of grass samples of affected and control (non-endemic) area was comparable. There was a highly positive correlation (r = + 0.664) between prevalence of dental fluorosis and fluoride content of ground water. It was concluded that fluoride intake through the water especially ground water contributed to the development of fluorosis in cattle. 相似文献
44.
SANJIB Kumar Das DIBYENDU Biswas SUDIPTO Roy 《应用与环境生物学报》2007,13(5):662-667
The benthic macroinvertebrate communities of two lotic aquatic habitats,namely,the Churni River(C-R)and the Jalangi River(J-R)were compared in this study.One lotic aquatic system(C-R)was polluted by organic pollutants due to discharge of unprocessed sewage water,while the other(J-R)was not affected by such pollution.Evaluations of various physico-chemical properties of water,sediment and different macroinvertebrate communities of the two tropical lotic systems were done in a period from January,2002 to December,2003.A long term temporal change in the macroinvertebrate communities was recorded due to increase in sediment rH value.Sediment redox potential affected by the anthropogenic activities was found to be an important factor for alteration of macroinvertebrate communities in these aquatic ecosystems.A positive correlation has been established between rH and Margalef index in this study.Potassium and the total count of coliform bacteria in water showed significantly higher values for the polluted Churni River than those for the Jalangi River.Fig 3,Tab 4,Ref 34 相似文献
45.
Effects of chromium and nickel on germination and growth in tolerant and non-tolerant populations of Echinochloa colona (L.) Link 总被引:1,自引:0,他引:1
The tolerance of populations of a grass, Echinochloa colona, growing abundantly on chromite minewaste dumps, was tested in two separate experiments. Seed-based experiments indicate that the populations growing naturally on uncontaminated sites, germinated better in nutrient solutions without metal than those collected from minewaste dumps. Metal tolerance indices were greater in the plant populations derived from metal contaminated sites and better growth of these plants was noted on mine spoil soil-mix in the ratio of 1:1; the percentage of seed germination and the rate of seedling growth, however, declined in a soil compost containing 25% mine spoil and 75% uncontaminated (control) soil. Populations of Echinochloa colona occurring naturally on chromite mine spoils, therefore, appear to have developed metal tolerance. It is maintained by a balanced and stable genetic system built up and adjusted by natural selection. Such material is very suitable to be used in restoration work designed to produce an effective vegetation cover to improve the derelict land and to reduce erosion. This finding might be useful in revegetation programmes on metalliferous minewastes. 相似文献
46.
47.
Romy Steenbeek Ruben C. Piek Marleen van Buul Jan A. R. A. M. van Hooff 《Behavioral ecology and sociobiology》1999,45(2):137-150
This study examines vigilance as a behavioural indicator of the importance of infanticide risk by comparing the infanticide
avoidance hypothesis with the predation avoidance and mate defence hypotheses for wild Thomas's langurs (Presbytis thomasi) in Sumatra. We found that all individuals were more vigilant in situations of high predation risk, i.e. lower in the trees
and in the absence of neighbours. Females were also more vigilant on the periphery of the group. However, there were variations
in vigilance levels that could not be accounted for by the predation avoidance hypothesis. Males without infants showed higher
levels of vigilance in areas of home range overlap than in non-overlap areas during the early phase of their tenure, strongly
suggesting mate defence. In these areas of home range overlap where Thomas's langur groups can interact, males may attack
females and infants, and so the infanticide risk for males and females with infants is likely to be high in these areas. Only
females with infants, but not males with infants or females without infants, showed higher vigilance levels in overlap areas
than in non-overlap areas; in addition, in overlap areas, females with an infant were more vigilant than females without an
infant, while this was not the case in non-overlap areas. Both females and males with infants were more vigilant high in the
trees than at medium heights in overlap areas but not elsewhere. These findings can only be explained by the infanticide avoidance
hypothesis. In contrast to predator attacks, infanticidal male attacks come from high in the canopy, and only occur in overlap
areas. There was a significant sex difference in vigilance, but males were only more vigilant than females without an infant,
and not more vigilant than females with an infant. We conclude that vigilance varied mainly in relation to the risk of predation
and infanticide. Mate competition only played a role for males during the early phase of their tenure. Predation risk seems
to offer the best explanation for vigilance for all individuals in the absence of infants. Both predation risk and infanticide
risk played a role for females and males with infants.
Received: 4 April 1998 / Accepted after revision: 6 September 1998 相似文献
48.
Introduction
This study presents a classification tree based alternative to crash frequency analysis for analyzing crashes on mid-block segments of multilane arterials.Method
The traditional approach of modeling counts of crashes that occur over a period of time works well for intersection crashes where each intersection itself provides a well-defined unit over which to aggregate the crash data. However, in the case of mid-block segments the crash frequency based approach requires segmentation of the arterial corridor into segments of arbitrary lengths. In this study we have used random samples of time, day of week, and location (i.e., milepost) combinations and compared them with the sample of crashes from the same arterial corridor. For crash and non-crash cases, geometric design/roadside and traffic characteristics were derived based on their milepost locations. The variables used in the analysis are non-event specific and therefore more relevant for roadway safety feature improvement programs. First classification tree model is a model comparing all crashes with the non-crash data and then four groups of crashes (rear-end, lane-change related, pedestrian, and single-vehicle/off-road crashes) are separately compared to the non-crash cases. The classification tree models provide a list of significant variables as well as a measure to classify crash from non-crash cases. ADT along with time of day/day of week are significantly related to all crash types with different groups of crashes being more likely to occur at different times.Conclusions
From the classification performance of different models it was apparent that using non-event specific information may not be suitable for single vehicle/off-road crashes.Impact on Industry
The study provides the safety analysis community an additional tool to assess safety without having to aggregate the corridor crash data over arbitrary segment lengths. 相似文献49.
Verma Sunirmit Das Ranjan 《Environmental science and pollution research international》2023,30(1):310-321
Environmental Science and Pollution Research - It is suggested by many works on solar stills that water thickness should be kept as low as possible to reduce its thermal inertia and obtain best... 相似文献
50.
Apurba Kumar Das Dilip Kumar Jha M. Prashanthi Devi Biraja Kumar Sahu N. V. Vinithkumar R. Kirubagaran 《Journal of Coastal Conservation》2014,18(3):249-255
The present study was carried out to determine the mangrove area water quality, mangrove diversity and density at Minnie Bay, Lalaji Bay and Aerial Bay (Andaman Islands, India). The physicochemical parameters such as salinity, nitrate, inorganic phosphate and total phosphorus varied significantly. Mangrove diversity was high at Minnie Bay while density at Aerial Bay. Rhizophora mucronata dominated at all three sites during the study period. Shannon-Wiener diversity index (H′?=?2.261) and Pielou’s evenness (J′?=?0.8348) were high at Minnie Bay. The higher species density cover (5.679 Nos./m2) was recorded at Aerial Bay. Bray-Curtis cluster analysis showed 63.35 % similarity and formed two clusters. Though uplift and subsidence of coastal land due to the Mw 9.3 Sumatra earthquake in 2004 has affected the mangrove vegetation, its rejuvenation was observed in the newly formed inter-tidal areas due to changes in coastal geomorphology. The comparative study on physicochemical parameters, mangrove coverage and conservation are discussed in detail. 相似文献