Showing papers by "North Eastern Hill University published in 1989"
TL;DR: Selective feeding by earthworms on organically rich substrates, which break down during passage through the gut, is likely to be responsible for the higher microbial populations and greater enzyme activity in the casts.
Abstract: Total populations of bacteria and fungi, dehydrogenase activity (as a measure of total potential microbial activity), and urease and phosphatase activities were determined in earthworm casts and surrounding laterite soils planted to pineapple. The casts contained higher microbial populations and enzyme activities than the soil. Except for fungal populations, statistically significant (P = 0.05) increases were found in all other parameters. Microbial populations and enzyme activities showed similar temporal trends with higher values in spring and summer and lower values in winter. The earthworm casts contained higher amounts of N, P, K and organic C than the soil (P = 0.05). Selective feeding by earthworms on organically rich substrates, which break down during passage through the gut, is likely to be responsible for the higher microbial populations and greater enzyme activity in the casts.
161 citations
TL;DR: The earlier suggestion that active ureogenesis through a functional o-u cycle does exist in some freshwater, air-breathing teleosts is strengthened.
Abstract: The ureogenic potential of five species of freshwater, air-breathing teleosts was studied. The activity of all five enzymes of the ornithine-urea (c-u) cycle could be assayed in four out of the five species. The enzymatic activities were generally high. Physiological levels of ammonia and urea and of enzymes of the o-u cycle have been considered to be associated with the potential for terrestrial life in different species. The species having an efficient o-u cycle had low levels of ammonia and high levels of urea in various tissues. Ammonia was the major excretory product in the aquatic medium in all five air-breathing species. However, the rate of excretion of urea was greater than that of exclusively freshwater teleosts reported earlier. There was apparently no diurnal variation in the rates of excretion of ammonia. The rate of excretion of urea was significantly higher during the night than during the day in only two of the species examined, namely, Heteropneustes fossilis and Anabas testudineus. These observations strengthen our earlier suggestion that active ureogenesis through a functional o-u cycle does exist in some freshwater, air-breathing teleosts.
104 citations
TL;DR: A new rapid air-drying technique which gives results comparable to critical point‐drying is described for scanning electron microscopy, using a trematode parasite, Homalogaster paloniae, as a test specimen.
Abstract: SUMMARY
A new rapid air-drying technique which gives results comparable to critical point-drying is described for scanning electron microscopy, using a trematode parasite, Homalogaster paloniae, as a test specimen.
85 citations
TL;DR: The urea uptake system was studied with regard to its repression and derepression in the cyanobacterium, Anabaena doliolum, suggesting that ammonium itself was the repressor signal.
Abstract: The urea uptake system was studied with regard to its repression and derepression in the cyanobacterium, Anabaena doliolum. The uptake of urea was energy-dependent and was repressed in ammonia grown cells. Repression of the urea uptake by ammonium did not require ammonium assimilation or de novo protein synthesis, suggesting that ammonium itself was the repressor signal. The derepression of the urea uptake system, however, required de novo protein synthesis and glutamine synthetase activity.
46 citations
TL;DR: In this paper, a systematic analysis of the IR and Raman spectra of tartaric acid (TA) [HOOC(CHOH)2 COOH], based on standard frequency correlations, deuteration shift and typical characteristics (with respect to intensity and width) of bands due to different modes, is reported.
Abstract: A systematic analysis of the IR and Raman spectra of tartaric acid (TA) [HOOC(CHOH)2 COOH], based on standard frequency correlations, deuteration shift and typical characteristics (with respect to intensity and width) of bands due to different modes, is reported. Almost all the vibrational modes of TA appear with two or more split components. The doublet structure of the νCH, νCO and δ modes arises mainly owing to crystallographically distinguishable sites for two identical oscillators. The splitting of other modes [viz. νCO, βCH, ν, ν and τCOOH] originates from differences in the crystallographic fields around the two identical oscillators and resonance interactions between such oscillators. The doublet of δ arises mainly from resonance interactions between two identical oscillators of two identical groups in TA.
34 citations
TL;DR: Nitrogenase was localized in heterocysts, with vegetative cells showing a label intensity comparable to the background, and Rubisco protein showed a comparable distribution pattern, but the average number of carboxysomes per vegetative cell was about 4 times higher.
Abstract: The qualitative distribution and quantitative estimates of nitrogenase (EC 1.7.99.2), glutamine synthetase (EC 6.3.1.2), phycoerythrin and ribulose 1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) were studied in the cyanobacterium Nostoc residing in internal cephalodia of the tripartite lichen Nephroma arcticum L. Polyclonal antisera, raised in rabbit against the proteins, and goat anti-rabbit IgG conjugated to 10 nm gold were used as probes to detect the antigens by transmission electron microscopy. Western blot analyses demonstrated the monospecificity of the antisera. Nitrogenase was localized in heterocysts, with vegetative cells showing a label intensity comparable to the background. Distribution of the antigen within the heterocysts was uniform. Glutamine synthetase labelling was very low, but appeared to be distributed in both cell types. An intense phycoerythrin labelling was associated with the thylakoid region of the vegetative cells, whereas a much lower labelling was observed in the heterocyst. No significant differences were found between cyanobionts in younger and older cephalodia except for the nitrogenase labelling, which was higher in heterocysts of the cyanobiont in younger cephalodia. Most of the ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) label was present in vegetative cells. The Rubisco label was pronounced in the carboxysomes, whereas the label in the cytoplasm, on a unit area basis, was much lower. Heterocysts showed a label intensity similar to that of the vegetative cell cytoplasm. In Nostoc of the bipartite lichen Peltigera canina L., the Rubisco protein showed a comparable distribution pattern, but the average number of carboxysomes per vegetative cell was about 4 times higher.
29 citations
TL;DR: Fourteen hundred and ninety-six domestic pigs from a sub-tropical and high-rainfall area of India were examined over a period of 18 months to ascertain their nematode parasite spectrum, finding Ascaris suum, the most prevalent species, is presumably of zoonotic importance.
29 citations
TL;DR: In this paper, the intermolecular distance, tilt angle, orientational distribution function and the orientational order parameters have been calculated for hexyl, octyl and decyl members of the homologous series bis-(4′-nalkoxybenzal)-2-chloro-1,4-phenylinediamine.
Abstract: The hexyl, octyl and decyl members of the homologous series bis-(4′-n-alkoxybenzal)-2-chloro-1,4-phenylinediamine have been studied by X-ray diffraction at different temperatures under various magnetic fields. The intermolecular distance the tilt angle, the orientational distribution function and the orientational order parameters have been calculated. The intermolecular distance, tilt angle and the ‘degree of ordering’ is found to depend on magnetic field strength. Order parameters 〈P 2〉 and 〈P 4〉 are found to be slightly lower for BHeCP, more or less equal for BOCP, and slightly higher for BDeCP than those predicted by mean field theory. 〈P 2〉 values for BHeCP snd BOCP agree well with the values obtained from refractive-index measurements, but for BDeCP our 〈P 2〉 values are higher.
24 citations
TL;DR: In this article, the effects of hill slope, terrace and valley agriculture were investigated for two cropping seasons, where the valleys and terraces were kept flooded during each cropping season while the hill slopes were cultivated with dryland practices, and a positive correlation was observed between dehydrogenase and urease activity and soil moisture content.
Abstract: Dehydrogenase activity (a measure of microbial biomass), urease activity and CO2 evolution were measured in soils planted to rice (Oryza sativa L.) under three different agricultural practices prevalent in hill regions. The effects of hill slope, terrace and valley agriculture were investigated for two cropping seasons. The valleys and terraces were kept flooded during each cropping season while the hill slopes were cultivated with dryland practices. The type of agricultural practice and the date of observation had a significant influence on enzyme activity and CO2 evolution. A positive correlation was observed between dehydrogenase and urease activity and soil moisture content. Dehydrogenase and urease activity and soil respiration were positively correlated among themselves. The activity of both enzymes and CO2 evolution were highest in valley soils followed by terrace and hill-slope sites.
23 citations
TL;DR: Interesting modifications with low-mass {ital W}{sub {ital R}}{sup {plus minus}} gauge bosons are found to be possible if the superheavy masses are nondegenerate, but satisfy the Coleman-Weinberg constraint.
Abstract: We investigate possible modifications of SO(10) predictions due to superheavy components of Higgs scalars, needed for the spontaneous symmetry breaking of the grand unified theory to effective gauge theories, where parity and SU(2){sub {ital R}} breakings are decoupled. Interesting modifications with low-mass {ital W}{sub {ital R}}{sup {plus minus}} gauge bosons are found to be possible if the superheavy masses are nondegenerate, but satisfy the Coleman-Weinberg constraint. With the single intermediate symmetry, SU(3){sub {ital C}}{times}SU(2){sub {ital L}} {times}SU(2){sub {ital R}}{times}U(1){sub {ital B}{minus}{ital L}}, even a factor of 10 nondegeneracy is found to lower the {ital W}{sub {ital R}}{sup {plus minus}} and {ital Z}{sub {ital R}} mass prediction by 4 orders, compared to earlier results, yielding {ital M}{sub {ital R}}{approx equal}100 TeV for sin{sup 2}{theta}{sub W}{approx equal}0.235. In the presence of the second intermediate symmetry, SU(3){sub {ital C}}{times}SU(2){sub {ital L}} {times}U(1){sub {ital R}}{times}U(1){sub {ital B}{minus}{ital L}}, which could survive down to {ital M}{sub {ital Z}{sub {ital R}}}{approx equal}500 GeV, we obtain 1 TeV{lt}{ital M} {sub {ital W}{sub {ital R}}}{lt}80 TeV for 0.238{gt}sin{sup 2}{theta}{sub {ital W}}{gt}0.231. The values of sin{sup 2}{theta}{sub {ital W}} can be lowered further if the nondegeneracy factor is allowed to be larger.
22 citations
TL;DR: The maximum values for the prevalence and overall mean eggs g-1 of faeces (EPG) were observed after the heavy rainfall season and remained at a relatively high level from July to December and the role of climatic factors in their prevalence is discussed.
01 Feb 1989
TL;DR: Growth and population dynamics of different cohorts of a serious exotic weedParthenium hysterophorus L. were studied for two years and growth and reproductive effort of the plant in surviving cohorts were adversely influenced by the density of their own cohorts as well as by the other cohort.
Abstract: Growth and population dynamics of different cohorts of a serious exotic weedParthenium hysterophorus L. were studied for two years. The seedlings were recruited in 3 successive cohorts in the beginning of rainy season. The density, survivorship and half life declined in successive cohorts. Although all the cohorts suffered heavy mortality during seedling stage, it was 100% in cohort III. Cohort I showed better growth than cohort II. Growth and reproductive effort of the plant in surviving cohorts were adversely influenced by the density of their own cohorts as well as by the other cohort. The established cohort strongly influenced the growth of the newly recruited plants through resource competition and/or allelochemics.
01 Mar 1989-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this paper, a simple nuclear track technique has been described to measure energy loss rate of any heavy ion in any medium and the results obtained from their measurements of energy-loss rate of 17.0 MeV/u 132 Xe ions in lead using special zinc phosphate (ZnP) glass detector.
Abstract: A simple nuclear track technique has been described to measure energy-loss rate of any heavy ion in any medium. Here we present the results obtained from our measurements of energy-loss rate of 17.0 MeV/u 132 Xe ions in lead using special zinc phosphate (ZnP) glass detector. The errors in measurement range from 5–10%. Experimental energy-loss data has been compared with calculated values. The significance of the results and scope of the track technique is discussed.
TL;DR: In this article, a new general synthesis of 3- and 3-4-substituted 4a-q, 3,4-annelated 7a-d and condensed tricyclic 9a-e thiophenes has been developed through Simmons-Smith reaction on the respective α-oxoketene dithioacetals.
TL;DR: The crystal and molecular structures of the nematogen 5-(trans-4-ethylcyclohexyl)-2-(4-cyanophenyl)-pyrimidine have been determined by direct methods.
Abstract: The crystal and molecular structures of the nematogen 5-(trans-4-ethylcyclohexyl)-2-(4-cyanophenyl)-pyrimidine have been determined by direct methods. The crystal belongs to the monoclinic system with space group P2/a, a = 18.437, b = 7.1027, c = 15.342 ° β = 106.07° and Z = 4. Least squares refinement leads to R = 0.049 (Rw = 0.048) for 2246 observed reflections. The molecules are in an almost fully extended conformation. Phenyl and pyrimidine rings are highly planar and lie almost in the ac plane. The cyclohexane ring is in chair form. Pairs of molecules related by a centre of symmetry are packed into sheets in the ac plane and these sheets are stacked along the b-axis. The structure is of a common type for a nematogen and the transition to the mesophase is a simple displacive type. The pairing of molecules resulting from the interaction between opposed dipoles of cyano-groups exists in both the crystalline and the nematic state.
TL;DR: Darzen's condensation of lithiobromoacetate with α-oxoketene dithioacetals affords the title furans 4 in moderate to good yields.
TL;DR: The addition of a six-dimensional operator is found to allow only high unification masses M/sub U/approx.(0.1--1)M/sub C/, and the grand-unification coupling constant is also found to be significantly smaller.
Abstract: Following the recent method due to Hill, Shafi, and Wetterich, we investigate the impact of higher-dimensional operators (dgreater than or equal to5) induced by gravity and compactification of extra dimensions, on the minimal SU(5) grand unified theory. Modifications caused by the d = 5 operator alone seem to be ruled out, even if the compactification scale M/sub C/ is as low as 10/sup 17/ GeV, as they require sin/sup 2/theta/sub W/less than or equal to0.203 in conflict with the present world average. The addition of a six-dimensional operator is found to allow only high unification masses M/sub U/approx.(0.1--1)M/sub C/, with M/sub C/ = 10/sup 17/--10/sup 19/ GeV and sin /sup 2/theta/sub W/approx. =0.22--0.24. The grand-unification coupling constant is also found to be significantly smaller.
TL;DR: In this article, the coordination of uranylnitrate with 5-Azoxines containing different substituents in the aniline fragment has been studied and it was shown that the chelation of azoxines occurred exclusively in the oxinate moiety through the O and N atoms.
Abstract: Coordinative interaction of uranylnitrate with 5-Azoxines containing different substituents in the aniline fragment have been studied. Infrared data suggests that the chelation of azoxines occurred exclusively in the oxinate moiety through the O and N atoms. These complexes have been characterised by spectral, magnetic measurements and elemental analysis.
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TL;DR: In this paper, the independence of the set of bordism classes of non-bounding Dold manifolds of a fixed dimension was discussed. And the condition in terms of m and n under which a Dold manifold P (m, n ) bounds is given.
TL;DR: In this paper, a systematic analysis of the IR and Raman spectra of dipotassium tartrate hemihydrate (K2C4H4O6 · ½H2O) in terms of the standard frequency correlations, deuteration shift and typical nature (with respect to intensity and width) of bands due to different modes is reported.
Abstract: A systematic analysis of the IR and Raman spectra of dipotassium tartrate hemihydrate (K2C4H4O6 · ½H2O) in terms of the standard frequency correlations, deuteration shift and typical nature (with respect to intensity and width) of bands due to different modes is reported. The bands due to the internal modes (excluding some skeletal modes) of the C4H4O ion appear as doublets. For certain modes (e.g. βCH, νC(OH) and δCOO), doublets arise due to interaction between two identical oscillators of two identical groups in COO(HO)HCCH(OH)COO2−, whereas for other modes (e.g. νCH, ν, ν, δCOH, and τCOO) they arise due to crystallographically distinguishable sites for two identical oscillators.
01 Oct 1989
TL;DR: In this article, the toxicity of a culture suspension of Anabaena doliolum as whole oil or aqueous extract was investigated and the hierachy of toxicity of the test oils was diesel > furnace oil > petrol > kerosene > crude, whereas reverse trend was obtained in case of other oils.
Abstract: Assam crude, kerosene, petrol, diesel and furnace oil administered into the culture suspension ofAnabaena doliolum as whole oil or aqueous extract exerted concentration dependent toxic effects. The hierachy of toxicity of the test oils was diesel > furnace oil > petrol > kerosene > crude. The oils rich in aromatics were most toxic and therefore estimation of this fraction might enable prediction of toxicity of an oil. Growth rate was a more sensitive criterion of oil toxicity as compared of final standing crop. In case of crude and kerosene, the whole oil application was more inhibitory than their respective aqueous extracts, whereas reverse trend was obtained in case of other oils. The study recommends toxicological evaluation of whole oils as well as their aqueous extracts for meaningful results.
TL;DR: Of the various criteria tested for possible relationships with the level of pollutants, species richness, Shannon diversity and biomass showed significant relationships, demonstrating the usefulness of algal criteria for monitoring oil pollution in running waters.
Abstract: Changes in epilithic algal communities colonizing introduced substrata were determined in a stream polluted with oil refinery effluent at Digboi (Assam, India). The number of algal taxa was reduced but the growth of blue-green algae, particularly two species ofOscillatoria, was encouraged. Epilithic biomass (as chlorophylla) also declined at polluted stations. The algal community of the upstream station was markedly different from the community occurring just after the confluence of effluent; however, the differences were gradually reduced downstream, indicating improvement in water quality. Of the various criteria tested for possible relationships with the level of pollutants, species richness, Shannon diversity and biomass showed significant relationships. The study demonstrates the usefulness of algal criteria for monitoring oil pollution in running waters.
TL;DR: In this article, the synthesis of complex difluorodihydroxomonoperoxothorates (IV), A 2 [Th(O 2 )F 2 (OH) 2 ]· n H 2 O (A = NH 4, n = 3; A = Na or K, n = 1) have been achieved from the reaction of hydrated thorium oxide, ThO 2 · n H2 O, with 30% H 2O 2 2 and 48% hydrofluoric acid in the concentration ratio of Th:H 2 O 2 :HF as
01 Mar 1989
TL;DR: The extent of damage to the intestine caused by the caryophyllid cestodes,ytocestus indicus, Djombangia penetrans, and by multiple infections comprising several species of cariesophyllids in the cat fish, Clarias batrachus L. is studied.
Abstract: The extent of damage to the intestine caused by the caryophyllid cestodes,Lytocestus indicus, Djombangia penetrans, and by multiple infections comprising several species of caryophyllids in the cat fish,Clarias batrachus L. is studied.Djombangia penetrans produced large nodules in the intestinal wall.Lytocestus indicus, being less deeply penetrative, caused ulceration of the affected tissue, with hyperplasia of the muscularis in severe cases of infection. Pathogenicity due to multiple infections was minimu, apparently limited to denudation of the mucosal folds.
TL;DR: It is found, for the first time, that such a scale and small Majorana neutrino masses are allowed when gravity-induced corrections due to a five-dimensional operator, arising out of spontaneous compactification of extra dimensions, are included.
Abstract: Signatures of quark-lepton unification can be experimentally verified by rare-kaon-decay processes provided the SU(4)/sub C/-breaking scale M/sub C//similar to/10/sup 5/--10/sup 6/ GeV. With the single intermediate symmetry, SU(2)/sub L/ x U(1)/sub R/ x SU(4)/sub C/ in SO(10), we find, for the first time, that such a scale and small Majorana neutrino masses are allowed when gravity-induced corrections due to a five-dimensional operator, arising out of spontaneous compactification of extra dimensions, are included. For such lower values of M/sub C/, the predicted proton lifetime is large depending upon the value of sin/sup 2/theta/sub W/ in the range 0.22--0.24. For still larger values of M/sub C/, neutrino masses and proton lifetime decrease, and the latter saturates the Irvine-Michigan-Brookhaven limit when M/sub C//similar to/10/sup 11/--10/sup 12/ GeV.
TL;DR: In this paper, the reaction of uranyl nitrate hexahydrate with salicylaldehyde, and acyl-and aroyl-dihydrazines in a 1:4:2 molar ratio in ethanol medium results in complexes of the composition [UO2(H3L2)2]·nH2O (n = 0, 2).
TL;DR: A detailed temperature-dependent Raman study of oriented single crystals of ammonium ions in the lattice-mode region from 10 to 300 K is reported, which provides deeper insight into the dynamics of ammonia ions inThe lattice.
Abstract: We report a detailed temperature-dependent Raman study of oriented single crystals of ${\mathrm{NH}}_{4}$${\mathrm{ClO}}_{4}$ and ${\mathrm{ND}}_{4}$${\mathrm{ClO}}_{4}$ in the lattice-mode region from 10 to 300 K. Based on the deuterium shift, characteristic changes in bandwidth with temperature, structural information, etc., we have assigned the Raman bands in the lattice-mode region, which provides deeper insight into the dynamics of ammonium ions in the lattice. We have observed temperature-dependent sidebands by \ifmmode\pm\else\textpm\fi{}19 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ (10 K) from the main bands associated with some of the internal and lattice modes of the ${\mathrm{NH}}_{4}^{+}$ ion below 30 K. These spectral features have been explained in terms of a model in which the ${\mathrm{NH}}_{4}^{+}$ ion rotates almost freely about one of the axes coinciding with the N-H(2)...O(1) bond while it performs librational motion about the two perpendicular axes below 30 K.
TL;DR: The data unequivocally support the contention that the buffalo-enzyme is similar to cathepsin B from other tissues with respect to these properties.
Abstract: Purification of cathepsin B from buffalo-spleen, a hitherto unstudied system has been achieved by a simple procedure developed by incorporating suitable modifications in the existing methods for isolation of the enzyme from other sources. The purified enzyme has a molecular weight of 25 KDa and its Stokes radius was found to be 2·24 nm. Effects of several reducing agents, urea and thiol-protease inhibitors such as leupeptin and antipain, have been studied and the data unequivocally support the contention that the buffalo-enzyme is similar to cathepsin B from other tissues with respect to these properties.
TL;DR: In this article, the Diels-Alder cycloadditions of the acyclic and cyclic vinylketene dithloacetals were studied and the dienes 4a-e and 4h-i were found to be unreactive towards weaker dienophiles like acrylonitrile,ethylacrylate and methylvinyl ketones.