Applications for nuclear phenomena generated by ultra-intense lasers     

Ledingham KW  McKenna P  Singhal RP 《Science (New York, N.Y.)》2003,300(5622):1107-1111

The amplification of laser light to generate powers large enough to affect the nucleus has been the desire of scientists since the invention of the laser 40 years ago. Many lasers, including tabletop varieties, now have pulse powers greater than the electrical power generated by all the world's power plants combined. When this power is focused to dimensions of a few microns, laser-driven nuclear phenomena can occur. Here we review the developments in this research field and describe the potential of laser produced proton, neutron, and heavy ion beams, together with isotope and isomer production.  相似文献   

Antifilarial activity of Azadirachta indica on cattle filarial parasite Setaria cervi     

Mishra V  Parveen N  Singhal KC  Khan NU 《Fitoterapia》2005,76(1):54-61

Alcohol and aqueous extracts of flowers of Azadirachta indica were tested in vitro for their potential antifilarial activity against whole worm, nerve muscle (n.m.) preparation and microfilariae of Setaria cervi. The effects of alcohol and aqueous extracts were similar in nature on the spontaneous movements of whole worm and nerve muscle preparation. On the whole worm, the response was characterized by initial increase in tone, rate and amplitude of contractions followed by reversible paralysis. The initial stimulant effect is likely to be due to irritant effect on the cuticle. Nerve muscle preparation responded to both extracts by inhibition of spontaneous movements followed by reversible paralysis; initial stimulation phase was absent. The inhibition was concentration related. Alcohol and aqueous extracts had almost similar lethal effect on the microfilariae of S. cervi, the LC50 being 15 and 18 ng/ml, respectively.  相似文献   

Economic contribution of wild edible mushrooms to a forest fringe ethnic community in some eastern lateritic parts of India     

Sumit Manna  Anirban Roy 《Journal of Forest Research》2014,19(1):52-61

Dry deciduous forests of the eastern lateritic part of India are a typical case where forest valuation is yet to be integrated with the non-timber forest products like wild edible mushrooms (WEMs), which have a wide use in subsistence and cash income. A detailed accounting of the production and utilization of WEMs harvested from that region was made to highlight the economic worth of WEMs to the Santal community of this region. The WEMs production in the forest was in a polynomial pattern during the monsoon period. The net present value of revenues from WEMs was estimated to be contributing 9.83 and 10.29 % of total annual income of a Santal family of the Choupahari and Gonpur forests, respectively. The ecological footprint of the Santal communities on WEMs was higher in the forest area which was closer to the local markets than did the distant ones. Forest areas of the eastern lateritic part of India have a strong potentiality to produce WEMs that may be helpful for socio-economic upliftment of local tribal communities through the development of entrepreneurship and policy making.  相似文献   

Phenology,pollination and breeding system of <Emphasis Type="Italic">Aegle marmelos</Emphasis> (Linn.) correa (Rutaceae) from India     

Vijay Kumar Singhal  Atula Salwan  Puneet Kumar  Jaspreet Kaur 《New Forests》2011,42(1):85-100

Studies on reproductive biology are difficult but useful in species like Aegle marmelos (Linn.) Correa which is of considerable socio-economic importance and possess morphogenetic variation and qualities of wider adaptability to different soils. Cytology, phenology, pollination, breeding system and natural regeneration of wild and cultivated trees from India revealed the existence of diploid (2n = 18) and tetraploid trees (2n = 36) in Pachmarhi hills and only diploid trees in Punjab plains and Shiwalik hills. The diploid and tetraploid trees showed normal meiosis and high pollen fertility. Phenological events which included leaf fall, leaf emergence, floral bud break, flowering and fruiting are nearly the same in wild and cultivated trees. Natural pollen transfer in the species was highly efficient. Levels of fruit set following open pollination was quite high and is reduced considerably following hand pollination probably due to some injury caused to stigma during experiments. Inspite of synchronous nature of anther dehiscence and stigmatic receptivity, selfing in a flower was avoided due to herkogamy. Some selfing, however, occurred through geitonogamous mode as bagging of panicles yielded 12.21 ± 0.99 to 14.12 ± 0.91% fruit set. High pollen ovule ratio (9,250–10,600) indicated toward the obligate outbreeding nature. The species suited to insect and wind mode of pollination. High amount of air borne pollen grains deposited on glycerine smeared glass microscopic slides suggested towards the wind mode of pollination. Though flowers are dull coloured a variety of insects visited the flowers due to sweet fragrance and stamen/pollen as food reward. Among insect pollinators, honey bee (Apis dorsata) was the major and legitimate pollinator while the rest were either minor pollinators or mere visitors. Inspite of high fruit/seed set, natural regeneration through seeds was poor as fallen fruits were destroyed by fungal pathogens and white ants. The species also propagated vegetatively through coppices and root suckers. It lacks agamospermy as bagging of emasculated flowers yielded no fruit. It is inferred that ‘bael’ which lacks agamospermy reproduced successfully through gamospermy (xenogamy and geitonogamy) and vegetative mode (coppices and root suckers). We also concluded that tetraploid trees growing in the Pachmarhi hills with large sized fruits possessed better potentialities in horticulture if planted through root suckers or coppices.  相似文献   

Estimation of Deposition Velocities for 85Sr, 131I, 137Cs on Spinach,Radish and Beans Leaves in a Tropical Region Under Simulated Fallout Conditions     

Singhal  R. K.  Narayanan  U.  Gurg  R. P. 《Water, air, and soil pollution》2004,158(1):181-192

Poly dispersive aerosols of SrCl₂, NaI, CsCl having a size distribution of 2.33 m (Activity Median Aerodynamic Diameter, [AMAD]) with a geometric standard deviation of 1.83 m are used for the determination of deposition velocity for ⁸⁵Sr, ¹³¹I and ¹³⁷Cs aerosols on tropical spinach (Spinicia olericia), radish (Raphanous sative) and beans (Phasolous valugeries) plant leaves. The experiments were carried out in a specially designed exposure chamber to simulate deposition under accidental releases of radioactivity in tropical environment. The rates of particles deposition are expressed as a function of plant surface area and of plant dry weight. The deposition velocities obtained are in the range of 10^–6 to 10^–7 m/s. These values differ significantly from those in temperate regions. The lower values for deposition velocities (v _g) for the tropical environment is attributed due to high humidity. Therefore, the deposition of suspended aerosols on leaf surfaces caused by impaction and Brownian diffusion becomes slower in tropical environment and resulted into lower value of deposition velocities.  相似文献   

Automatic analysis, theme generation, and summarization of machine-readable texts   总被引：1，自引：0，他引：1  

Salton G  Allan J  Buckley C  Singhal A 《Science (New York, N.Y.)》1994,264(5164):1421-1426

Vast amounts of text material are now available in machine-readable form for automatic processing. Here, approaches are outlined for manipulating and accessing texts in arbitrary subject areas in accordance with user needs. In particular, methods are given for determining text themes, traversing texts selectively, and extracting summary statements that reflect text content.  相似文献   

Heterochromatic silencing and HP1 localization in Drosophila are dependent on the RNAi machinery     

Pal-Bhadra M  Leibovitch BA  Gandhi SG  Rao M  Bhadra U  Birchler JA  Elgin SC 《Science (New York, N.Y.)》2004,303(5658):669-672

Genes normally resident in euchromatic domains are silenced when packaged into heterochromatin, as exemplified in Drosophila melanogaster by position effect variegation (PEV). Loss-of-function mutations resulting in suppression of PEV have identified critical components of heterochromatin, including proteins HP1, HP2, and histone H3 lysine 9 methyltransferase. Here, we demonstrate that this silencing is dependent on the RNA interference machinery, using tandem mini-white arrays and white transgenes in heterochromatin to show loss of silencing as a result of mutations in piwi, aubergine, or spindle-E (homeless), which encode RNAi components. These mutations result in reduction of H3 Lys9 methylation and delocalization of HP1 and HP2, most dramatically in spindle-E mutants.  相似文献   

Comparison of hemodynamic, clinicopathologic, and gastrointestinal motility effects and recovery characteristics of anesthesia with isoflurane and halothane in horses undergoing arthroscopic surgery     

Durongphongtorn S  McDonell WN  Kerr CL  Neto FJ  Mirakhur KK 《American journal of veterinary research》2006,67(1):32-42

OBJECTIVE: To compare hemodynamic, clinicopathologic, and gastrointestinal motility effects and recovery characteristics of halothane and isoflurane in horses undergoing arthroscopic surgery. ANIMALS: 8 healthy adult horses. PROCEDURE: Anesthesia was maintained with isoflurane or halothane (crossover study). At 6 intervals during anesthesia and surgery, cardiopulmonary variables and related derived values were recorded. Recovery from anesthesia was assessed; gastrointestinal tract motility was subjectively monitored for 72 hours after anesthesia. Horses were administered chromium, and fecal chromium concentration was used to assess intestinal transit time. Venous blood samples were collected for clinicopathologic analyses before and 2, 24, and 48 hours after anesthesia. RESULTS: Compared with halothane-anesthetized horses, cardiac index, oxygen delivery, and heart rate were higher and systemic vascular resistance was lower in isoflurane-anesthetized horses. Mean arterial blood pressure and the dobutamine dose required to maintain blood pressure were similar for both treatments. Duration and quality of recovery from anesthesia did not differ between treatments, although the recovery periods were somewhat shorter with isoflurane. After isoflurane anesthesia, gastrointestinal motility normalized earlier and intestinal transit time of chromium was shorter than that detected after halothane anesthesia. Compared with isoflurane, halothane was associated with increases in serum aspartate transaminase and glutamate dehydrogenase activities, but there were no other important differences in clinicopathologic variables between treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with halothane, isoflurane appears to be associated with better hemodynamic stability during anesthesia, less hepatic and muscle damage, and more rapid return of normal intestinal motility after anesthesia in horses undergoing arthroscopic procedures.  相似文献   

Erratum to: Phenology,pollination and breeding system of <Emphasis Type="Italic">Aegle marmelos</Emphasis> (Linn.) Correa (Rutaceae) from India     

Vijay Kumar Singhal  Atula Salwan  Puneet Kumar  Jaspreet Kaur 《New Forests》2012,43(3):395-395

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Contribution of NTFPs on livelihood of forest-fringe communities in Jaldapara National Park,India     

Lakpa Doma Lepcha  Nazir Ahmad Pala  Vineeta  Prabhat Kumar Pal  Sumit Chakravarty 《Journal of Sustainable Forestry》2019,38(3):213-229

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