Showing papers by "North Eastern Hill University published in 2006"

Biodiversity conservation in sacred groves of Manipur, northeast India: population structure and regeneration status of woody species

Abstract: Sacred groves are forest patches conserved by the local people intertwined with their socio-cultural and religious practice. These groves harbour rich biodiversity and play a significant role in the conservation of biodiversity. Population structure and regeneration status of woody species were studied during 2001–2002 in the four sacred groves of Manipur, a state in north east India. A total of 96 woody species was recorded from the four groves, the highest being Konthoujam Lairembi sacred grove (55 species) and lowest in Heingang Marjing sacred grove having 42 species. The density-diameter distribution of woody species in the four groves showed highest stand density and species richness in the lowest girth class (30–60 cm) and decreased in the succeeding girth classes. Overall population structure of the groves based on the number of tree seedlings, saplings and adults, displayed a greater proportion of seedlings followed by saplings and adults while for the selected tree species it varied seasonally and recruitment of species increased during rainy season attaining peak during June. Regeneration status of the four sacred groves based on strength of different age groups in their population showed good regeneration. High occurrence of ‘additional species’ to the groves may be due to the invasion through dispersal from other areas. Possibly, the prevailing favourable microenvironmental conditions contributed to their establishment and growth in the groves. Absence of seedlings and saplings of some of the species in the groves may be due to their poor seed germination and establishment of seedlings in the forest.

Global Patterns in Human Mitochondrial DNA and Y-Chromosome Variation Caused by Spatial Instability of the Local Cultural Processes

Abstract: Because of the widespread phenomenon of patrilocality, it is hypothesized that Y-chromosome variants tend to be more localized geographically than those of mitochondrial DNA (mtDNA). Empirical evidence confirmatory to this hypothesis was subsequently provided among certain patrilocal and matrilocal groups of Thailand, which conforms to the isolation by distance mode of gene diffusion. However, we expect intuitively that the patterns of genetic variability may not be consistent with the above hypothesis among populations with different social norms governing the institution of marriage, particularly among those that adhere to strict endogamy rules. We test the universality of this hypothesis by analyzing Y-chromosome and mtDNA data in three different sets of Indian populations that follow endogamy rules to varying degrees. Our analysis of the Indian patrilocal and the matrilocal groups is not confirmatory to the sex-specific variation observed among the tribes of Thailand. Our results indicate spatial instability of the impact of different cultural processes on the genetic variability, resulting in the lack of universality of the hypothesized pattern of greater Y-chromosome variation when compared to that of mtDNA among the patrilocal populations.

Some new test functions for global optimization and performance of repulsive particle swarm method

Abstract: In this paper we introduce some new test functions to assess the performance of global optimization methods. These functions have been selected partly because several of them are aesthetically appealing and partly because a few of them are really difficult to optimize, while all the functions are multi-modal. Each function has been graphically presented to appreciate its geometrical appearance. To optimize these functions we have used the Repulsive Particle Swarm (RPS) method. We have also appended a computer program of the RPS method. Except two functions, namely the 'crowned cross' and the 'cross-legged table' functions all other new test functions are optimized by the RPS program.The program has also been tested with success on a number of well-established benchmark functions. However, the program fails miserably in optimizing the Bukin and a couple of other functions. Note: Readers should beware of the plagiarism by one Mr. Sanjeev K Singh, Tezpur University, Assam, who, in his article "A Comparative Study of Genetic Algorithm, Improved-Repulsive Particle Swarm Optimization and Simulated Annealing" published in the proceedings of Advances in Computational Optimization and Analysis of Systems (COSA 2007), 6-9 February, 2007 Outreach Centre, IIT, Kanpur, attributes introduction of some new functions (Bird function, Penholder function, Cross function, etc) and the improved Particle Swarm method to himself.

Global Optimization by Differential Evolution and Particle Swarm Methods: Evaluation on Some Benchmark Functions

Abstract: In this paper we compare the performance of the Differential Evolution (DE) and the Repulsive Particle Swarm (RPS) methods of global optimization. To this end, seventy test functions have been chosen. Among these test functions, some are new while others are well known in the literature; some are unimodal, the others multi-modal; some are small in dimension (no. of variables, x in f(x)), while the others are large in dimension; some are algebraic polynomial equations, while the other are transcendental, etc. FORTRAN programs of DE and RPS have been appended. Among 70 functions, a few have been run for small as well as large dimensions. In total, 73 optimization exercises have been done. DE has succeeded in 65 cases while RPS has succeeded in 55 cases. In almost all cases, DE has converged faster and given much more accurate results. The convergence of RPS is much slower even for lesser stringency on accuracy. Some test functions have been hard for both the methods. These are: Zero-Sum (30D), Perm#1, Perm#2, Power-sum, and Bukin-6 functions. From what we find, one cannot reach at the definite conclusion that the DE performs better or worse than the RPS. None could assure a supremacy over the other. Each one faltered in some cases; each one succeeded in some others. However, DES is unquestionably faster, more accurate and more frequently successful than the RPS. It may be argued, nevertheless, that alternative choice of adjustable parameters could have yielded better results in either method's case. The protagonists of either method could suggest that. Our purpose is not to join with the one or the other. We simply want to highlight that in certain cases they both succeed, in certain other case they both fail and each one has some selective preference over some particular type of surfaces. What is needed is to identify such structures and surfaces that suit a particular method most. It is needed that we find out some criteria to classify the problems that suit (or does not suit) a particular method. This classification will highlight the comparative advantages of using a particular method for dealing with a particular class of problems.

Cambial activity and annual rhythm of xylem production of elephant apple tree (Dillenia indica Linn.) in relation to phenology and climatic factor growing in sub-tropical wet forest of northeast India

Abstract: The interrelationship between phenological events, climatic factors, periodicity of cambial activity and seasonal production of xylem was examined in Dillenia indica L. (Dilleniaceae) growing in sub-tropical wet forest of Meghalaya state, India. The reactivation of cambial activity was seen in the first week of May, 15 days after sprouting of new leaves and buds. The activity of cambium and xylem production gradually declined toward December and ceased from January to April end. There was correlation between leaf fall and cambial dormancy. It was evident from the correlation and regression analysis, the relationship between cambial activity, xylem production with climatic factors, the monthly mean minimum temperature plays an important role for the cambial activity and xylem production rather than influence by rainfall and relative humidity in D. indica L. The data were discussed in the light of cambial activity, xylem production and phenological events.

Photocount distribution of photons emitted from three sites of a human body.

Abstract: Spontaneous photon emission from 30 sites on the skin of a live human subject is measured at different times and on different days. Signals from three representative sites of low, intermediate and high intensities are selected for further analysis. Fluctuations in these signals are measured by the probabilities of detecting different numbers of photons in a bin. The probabilities have non-classical features and are well described by the signal in a quantum squeezed state of photons. Measurements with bins of three sizes yield same values of three parameters of the squeezed state. A procedure for making correction due to background noise is developed. The correction changes the parameters of the quantum state. The new state appears more like a coherent state of photons.

Surplus Labour, Social Structure and Rural to Urban Migration: Evidence from Indian Data

Abstract: This paper examines the empirical implications of the Lewis Model with respect to the relationship between the phenomenon of surplus labour in rural areas and out-migration from these areas to urban areas. It does so by using a micro-economic data set of migrants and non-migrants for India. We find strong empirical support for the key prediction of the Lewis Model that rural-urban migration will be influenced by the existence of surplus labour in the rural areas where the migrants originate. We also find that the phenomenon of rural-urban migration is more complex than viewed within a simple Lewis framework. Social structure and the possession of human capital are important determinants of rural-urban migration – individuals from scheduled castes and scheduled tribes and those with little or no education are less likely to migrate to urban areas. Given that scheduled castes and scheduled tribe households along with households with low levels of educational attainment are more likely to be poor, our findin...

Repulsive Particle Swarm Method on Some Dicult Test Problems of Global Optimization

Abstract: In this paper we test a particular variant of the (Repulsive) Particle Swarm method on some rather difficult global optimization problems. A number of these problems are collected from the extant literature and a few of them are newly introduced. First, we introduce the Particle Swarm method of global optimization and its variant called the 'Repulsive Particle Swarm' (RPS) method. Then we endow the particles with some stronger local search abilities - much like tunneling - so that each particle can make a search in its neighborhood to optimize itself. Next, we introduce the test problems, the existing as well as the new ones. We also give plots of some of these functions to help appreciation of the optimization problem. Finally, we present the results of the RPS optimization exercise and compare the results with those obtained by using the Genetic algorithm (GA)and/or Simulated annealing (SA) method. We append the (Fortran) computer program that we have developed and used in this exercise. Our findings indicate that neither the RPS nor the GA/SA method can assuredly find the optimum of an arbitrary function. In case of the Needle-eye and the Corana functions both methods perform equally well while in case of Bukin's 6th function both yield the values of decision variables far away from the right ones. In case of zero-sum function, GA performs better than the RPS. In case of the Perm #2 function, both of the methods fail when the dimension grows larger. In several cases, GA falters or fails while RPS succeeds. In case of N#1 through N#5 and the ANNs XOR functions the RPS performs better than the Genetic algorithm. It is needed that we find out some criteria to classify the problems that suit (or does not suit) a particular method. This classification will highlight the comparative advantages of using a particular method for dealing with a particular class of problems.

Anticestodal efficacy of Psidium guajava against experimental Hymenolepis diminuta infection in rats.

Abstract: Objective: To investigate the anticestodal efficacy of Psidium guajava L. leaf extract. Materials and Methods: Anticestodal efficacy was evaluated using experimental Hymenolepis diminuta infection in rats. The leaf extract was administered orally to different groups of experimentally infected H. diminuta infections in rats. The efficacy was adjudged in terms of parasite eggs/g (EPG) of faeces count before and after treatment, direct count of surviving worms remaining in small intestines after completion of treatment and by host clearance of parasite. In all the experiments, the effect of leaf extract was compared with a standard anticestodal drug, praziquantel (PZQ). Results: The leaf extract showed reduction in parasite EPG of faeces count in a dose-dependent manner. It further showed comparatively low recovery of worms including scolices in the small intestine and host clearance of parasite in a dose dependent manner. In all the experimental models the anticestodal efficacy of leaf extract was significantly comparable with that of PZQ. Conclusion: The leaf extract of P. guajava possesses anticestodal efficacy. Study supports its folk medicinal use in the treatment of intestinal-worm infections in northeastern part of India.

Theoretical study of the substituent effects on the S-H bond dissociation energy and ionization energy of 3-pyridinethiol: Prediction of novel antioxidant.

Abstract: The S-H bond dissociation enthalpies [BDE(S-H)] of a set of 5-X- and 6-X-3-pyridinethiols (X ) F, Cl, CH3, OCH3 ,N H 2, N(CH3)2 ,C F 3, CN, and NO2) have been computed using the density functional theory based (RO)B3LYP procedure with 6-311++G(2df,2p) basis set. The effects of substituents on the BDE(SH), proton affinity of the pyridinethiol anion [PA(S - )] and ionization energy (IE) are analyzed and their correlations with Hammett’s substituent constants are examined. Subsequently, a series of 6-substituted 3-pyridinethiols have been explored to find out their antioxidant potentials. Finally, a number of 3-pyridinethiol based compounds are theoretically proposed as novel antioxidants.

The effects of cyclophosphamide alone and in combination with ascorbic acid against murine ascites Dalton's lymphoma

Abstract: Objective : To evaluate the therapeutic activity of cyclophosphamide alone and in combination with ascorbic acid against murine ascites Dalton's lymphoma. Materials and Methods: Cyclophosphamide (CP) is an anticancer drug with immunosuppressive activity, while ascorbic acid (AA) is an antioxidant. Ascites Dalton's lymphoma (DL) was maintained by intraperitoneal (i.p.) transplantation of tumor cells in Swiss albino mice. Tumor transplanted mice were divided into four groups. Group-I mice received normal saline only and served as control. Group-II mice were given 1% ascorbic acid through drinking water from the 5th to the 10th day. Group-III mice were injected i.p. with a single dose of CP (200 mg/kg) on the 10th day of tumor transplantation. Group IV mice received 1% ascorbic acid from the 5th day onwards and, then, a single dose of CP, i.p., on the 10th day of tumor transplantation. In groups III and IV, after 24, 48, 72, and 96 h of CP treatment the liver, kidneys, spleen, and tumor tissue were collected for biochemical determinations. In group II, which received AA only from the 5th to the 10th day, the same tissues were collected on the 10th day of tumor transplantation. The changes in reduced glutathione (GSH) and carbohydrate in tumor cells as well as the liver, kidney, and spleen of tumor-bearing mice in relation to the antitumor activity of CP alone or in combination with AA were evaluated. The quantitative changes in sialic acid level of DL cells under these treatment conditions were also determined. Results: AA and CP combination in tumor-bearing mice was found to be more effective against DL as it caused a 257% increase in life span compared with control, while it was 106% with AA and 188% with CP alone (ANOVA, P 0.001). The reduced glutathione (GSH) level increased in DL cells with tumor growth. Compared with CP alone, the combination treatment (AA + CP) resulted in a more pronounced effect causing decreases in non-protein thiol (NPSH) as well as sialic acid levels in DL cells (ANOVA, P 0.001). Conclusion: The drug-mediated lowering of GSH levels in DL cells may be involved in the cytotoxicity due to CP (group-III) as well as AA + CP combination (group-IV). An overall decrease in the sialic acid content of DL cells after combination treatment may also play a role to bring about alterations in the tumor cells, cell-cell interaction and enhanced tumor regression.

Asian and non-Asian origins of Mon-Khmer- and Mundari-speaking Austro-Asiatic populations of India.

Abstract: In the present study, we analyzed 1,686 samples from 31 tribal populations of India for the mitochondrial DNA 9-base-pair deletion/insertion polymorphism, and characterized them based on the relevant mitochondrial DNA coding-region single nucleotide polymorphisms and hypervariable region I motifs, to test the genetic origins of the ethnically and linguistically heterogeneous Austro-Asiatic tribes of India. A comparative analysis of our results with the existing data suggests multiple origins of Austro-Asiatic tribes in India, and particularly the Asian and non-Asian origins of the Mon-Khmer and the Mundari populations. We also identified a novel subclade of haplogroup B in the Mon-Khmer Khasi tribes that distinguishes them from the Nicobarese, indicating two different waves of migration of the Mon-Khmer tribes in India.

Intramolecular proton transfer in 4-methyl-2,6-diformyl phenol and its derivative studied by femtosecond transient absorption spectroscopy

Abstract: Dynamics of excited state intramolecular proton transfer (ESIPT) and solution phase fluorescence properties of 4-methyl-2,6-diformyl phenol (MFOH) and its derivative, 4-methyl-2,6-diacetyl phenol (MAOH), have been monitored by nanosecond time correlated single photon counting and femtosecond transient absorption techniques. Time evolution of the transient absorption data reveals that both the compounds undergo an ultrafast proton transfer, yet with a significantly slower rate constant of about 4–5 × 10 12 s −1 compared to the other intramolecularly hydrogen bonded systems reported recently. This is explained on the basis of large skeletal rearrangement necessary for the proton transfer to occur. The ultrafast ESIPT process is followed by rapid intramolecular vibrational relaxation (IVR) with a time constant of few picoseconds before fluorescence emission occurs from the proton transferred keto structure in the excited state potential energy surface.

Seed Size as a Predictor of Germination Success and Early Seedling Growth in ‘Hollong’ (Dipterocarpus macrocarpus Vesque)

Abstract: In species with seeds losing viability shortly after dispersal and exhibiting inherently low germination, quick decisions are required with respect to seeds that should be selected to maximize germination success and vigorous growth of seedlings. In ‘hollong’ (Dipterocarpus macrocarpus Vesque), I address the following questions: (a) are seeds that germinate randomly distributed within a seed population, (b) are subpopulations of viable and non-viable seeds separable, (c) does seed size predict which seeds germinate and (d) does seed size predict time required for germination and seedling vigour? Two estimators of seed size, diameter and weight, demonstrated a significant positive linear relationship endorsing assumption that accumulation of mass increases with increase in diameter of seeds. A threshold for selection of potential seeds for germination could not be derived from diameter measurements since seeds in an entire range of diameter did or did not germinate. All seeds <11 g did not germinate, but this threshold lies at the far lower end of the weight range and allows rejection of only a few seeds and acceptance of many seeds that will not germinate. A risk of potential seeds being rejected or non-viable seeds being picked exists if selection was derived from either diameter or weight. However, viable seeds could be better predicted from a scatter-plot of diameter on x-axis and weight on y-axis. Seeds showed a fan-shaped scatter and those developing the lower blade of the fan did not germinate while those following the handle were successful. Hence, two subpopulations segregated, but with a fuzzy edge. Mean diameter and mean weight of germinated seeds were significantly greater than those of ungerminated seeds. Most ungerminated seeds were those that had relatively smaller weight compared to their diameter. Although some large diameter seeds with small weight did germinate, but failed to develop into seedlings. Germination time and seedling vigour parameters (height, leaf number and collar diameter) were correlated both with diameter and weight. However, weight appears to have mattered more than diameter in germination success and early seedling growth.

Performance of Differential Evolution and Particle Swarm Methods on Some Relatively Harder Multi-Modal Benchmark Functions

Abstract: This paper aims at comparing the performance of the Differential Evolution (DE) and the Repulsive Particle Swarm (RPS) methods of global optimization. To this end, some relatively difficult test functions have been chosen. Among these test functions, some are new while others are well known in the literature. We use DE method with the exponential crossover scheme as well as with no crossover (only probabilistic replacement). Our findings suggest that DE (with the exponential crossover scheme) mostly fails to find the optimum in case of the functions under study. Of course, it succeeds in case of some functions (Perm #2, Zero-sum) for very small dimension, but begins to falter as soon as the dimension is increased. In case of DCS function, it works well up to dimension=5. When we use no crossover (only probabilistic replacement) we obtain better results in case of several of the functions under study. In case of Perm #1, Perm #2, Zero-sum, Kowalik, Hougen and Power-sum functions, a remarkable advantage is there. Whether crossover or no crossover, DE falters when the optimand function has some element of randomness. This is indicated by the functions: Yao-Liu #7, Fletcher-Powell, and "New function #2". DE has no problems in optimizing the "New function #1". But the "New function #2" proves to be a hard nut. However, RPS performs much better for such stochastic functions. When the Fletcher-Powell function is optimized with non-stochastic vector, DE works fine. But as soon as is stochastic, it becomes unstable. Thus, it may be observed that an introduction of stochasticity into the decision variables (or simply added to the function as in Yao-Liu #7) interferes with the fundamentals of DE, which works through attainment of better and better (in the sense of Pareto improvement) population at each successive iteration. The paper concludes: (1) for different types of problems, different schemes of crossover (including none) may be suitable or unsuitable, (2) Stochasticity entering into the optimand function may make DE unstable, but RPS may function well.

Expression of ornithine-urea cycle enzymes in early life stages of air-breathing walking catfish Clarias batrachus and induction of ureogenesis under hyper-ammonia stress.

Abstract: The air-breathing walking catfish Clarias batrachus is a potential ureogenic teleost with having a full complement of ornithine–urea cycle (OUC) enzymes expressed in various tissues. The present study was aimed at determining the pattern of nitrogenous waste excretion in the form of ammonia-N and urea-N along with the changes of tissue ammonia and urea levels, and the expression of OUC enzymes and glutamine synthetase (GSase) in early life stages of this teleost, and further, to study the possible induction of ureogenesis in 15-day old fry under hyper-ammonia stress. The ammonia and urea excretion was visible within 12 h post-fertilization (hpf), which increased several-fold until the yolk was completely absorbed by the embryo. Although all the early developing stages were primarily ammoniotelic, they also excreted significant amount of nitrogen (N) in the form of urea-N (about 35–40% of total N). Tissue levels of ammonia and urea also increased along with subsequent developmental stages at least until the yolk absorption stage. All the OUC enzymes and GSase were expressed within 4–12 hpf showing an increasing trend of activity for all the enzymes until 350 hpf. There was a significant increase of activity of GSase, carbamyl phosphate synthetase III (CPSase III) and argininosuccinate lyase enzymes (ASL), accompanied with significant increase of enzyme protein concentration of at least two enzymes (GSase and CPSase III) in the 15-day old fry following exposure to 10 mM NH4Cl as compared to respective controls kept in water over a period of 72 h. Thus, it appears that the OUC enzymes are expressed in early life stages of walking catfish like other teleosts, but at relatively high levels and remain expressed all through the life stages with a potential of stimulation of ureogenesis throughout the life cycle as a sort of physiological adaptation to survive and breed successfully under hyper-ammonia and various other environmental-related stresses.

Synthesis, characterization and crystal structures of triorganotin(IV) complexes of 4‐[(E)‐2‐(3‐formyl‐4‐ hydroxyphenyl)‐1‐diazenyl]‐ and 4‐{(E)‐4‐hydroxy‐3‐[(E)‐4‐(aryl)iminomethyl]phenyldiazenyl}‐benzoic acids and toxicity studies of their tri‐n‐butyltin(IV) derivatives on the Aedes aegypti and Anopheles stephensi mosquito larvae

Abstract: Triorganotin(IV) complexes of 4-[(E)-2-(3-formyl-4-hydroxyphenyl)-1-diazenyl]- and 4-{(E)-4-hydroxy-3-[(E)-4-(aryl)iminomethyl]phenyldiazenyl}-benzoic acids (aryls = 4-CH3, 4-Br, 4-Cl, 4-OCH3) have been synthesized. The structures have been characterized by 1H, 13C, 119Sn NMR, IR and 119mSn Mossbauer spectroscopies. The crystal structures of Ph3Sn[O2CC6H4{NN(C6H3-4-OH[C(H)NC6H4CH3-4])}-p] and nBu3Sn[O2CC6H4{NN(C6H3-4-OH[C(H)NC6H4Br-4])}-p] are also reported. The 119Sn Mossbauer and 119Sn NMR data indicate that the tri-n-butyltin(IV) and triphenyltin(IV) complexes have a tetrahedral geometry in the solid state as well as in solution. Toxicity studies of the tri-n-butyltin(IV) complexes on the second larval instar of the Aedes aegypti and Anopheles stephensi mosquito larvae indicated that the complexes are effective larvicides. The LC50 values range from 1.21 to 3.38 µM for the Ae. aegypti and from 0.83 to 2.31 µM for the An. stephensi. Copyright © 2006 John Wiley & Sons, Ltd.

Global Optimization by Particle Swarm Method:A Fortran Program

Abstract: Programs that work very well in optimizing convex functions very often perform poorly when the problem has multiple local minima or maxima. They are often caught or trapped in the local minima/maxima. Several methods have been developed to escape from being caught in such local optima. The Particle Swarm Method of global optimization is one of such methods. A swarm of birds or insects or a school of fish searches for food, protection, etc. in a very typical manner. If one of the members of the swarm sees a desirable path to go, the rest of the swarm will follow quickly. Every member of the swarm searches for the best in its locality - learns from its own experience. Additionally, each member learns from the others, typically from the best performer among them. Even human beings show a tendency to learn from their own experience, their immediate neighbours and the ideal performers. The Particle Swarm method of optimization mimics this behaviour. Every individual of the swarm is considered as a particle in a multidimensional space that has a position and a velocity. These particles fly through hyperspace and remember the best position that they have seen. Members of a swarm communicate good positions to each other and adjust their own position and velocity based on these good positions. The Particle Swarm method of optimization testifies the success of bounded rationality and decentralized decisionmaking in reaching at the global optima. It has been used successfully to optimize extremely difficult multimodal functions. Here we give a FORTRAN program to find the global optimum by the Repulsive Particle Swarm method. The program has been tested on over 90 benchmark functions of varied dimensions, complexities and difficulty levels.

Syntheses of (η6-p-cymene)ruthenium(II) piano-stool amine complexes: molecular structure of [(η6-C10H14)RuCl2(H2N-C6H4-p-Cl)]

Abstract: The dimeric complex [{(η6-p-cymene)Ru(μ-Cl)Cl}2] (1) reacts with S,N-donor Schiff base ligands, para-substituted S-(thiophen-2-ylmethylene)phenylamines in methanol to give mononuclear amine complexes of the type [(η6-p-cymene)RuCl2(NH2–C6H4–p-X)] {X = H (2a); X = CH3 (2b); X = OCH3 (2c); X = Cl (2d); Br (2e) X = NO2 (2f), respectively} by hydrolysis of the imine group of the ligand after coordination to the metal. The complexes were characterized by analysis and IR and NMR spectroscopy. The molecular structure of [(η6-C10H14)RuCl2(H2N–C6H4–p-Cl)] (2d) was established by a single-crystal X-ray diffraction study.

Methyl and phenyl substitution effects on the proton affinities of hydrides of first and second row elements and substituent effects on the proton affinities of ring carbons in benzene: a DFT study.

Abstract: Theoretical calculations using B3LYP density functional theory (DFT) with the 6-311++G(d,p) basis set have been performed to determine proton affinities (PAs) of a series of H-X compounds and the corresponding methyl- (H 3 C-X) and phenyl- (Ph-X) substituted derivatives with a variety of proton acceptor atoms, such as C, O, N, F, Si, P, S, Cl, etc. Our results illustrate an interesting substituent effect on PAs. The PAs of ring carbon atoms for a series of monosubstituted benzene molecules (Y-C 6 H 5 ; Y = F, Cl, CH 3 , OCH 3 , NH 2 , PH 2 , OH, SH, SiH 3 , CN, CF 3 , and NO 2 ) have also been estimated. Correlations between proton affinities of H-X, H 3 C-X, and Ph-X and substituent effects on the PAs of the ring carbon atoms for a series of monosubstituted benzene molecules have been studied. It has been observed that substituent effects on the PAs of the ring carbon atoms follow a good Hammett-type correlation.