Computational Mechanism Design: A Call to Arms

Game theory has developed powerful tools for analyzing decision making in systems with multiple autonomous actors. These tools, when tailored to computational settings, provide a foundation for building multiagent software systems. This tailoring gives rise to the field of computational mechanism design, which applies economic principles to computer systems design

Decarboxylation of Hydrogencarbonatopentamminecobalt(III) in Aquo-organic solvent media

The decarboxylation of hydrogencarbonatopentaamminecobalt(III) has been investigated in aqueous, 99% D2O and aquo-organic solvent media (0-70 wt.% of cosolvent) at 15 ≤ t/°C ≤ 40 (I = 0.02 mol dm-3), using methanol, propan-2-01, tert-butyl alcohol, ethylene glycol, acetone, acetonitrile, DMSO and ethylene carbonate as cosolvents. The solvent isotope effects on rate (kH2O/kD2O=O 1.0 at 1535°C) and activation parameters (ΔH≠ = 77.7 ± 1.0, 77.8 ± 0.9 kJ mol-1 and ΔS≠ = 16 ± 3, 16 ± 3 J K-1 mol-1 for aqueous and 99% D,O media, respectively) were negligible. The decarboxylation rate constant increased with increasing mole fraction (Xorg) of the cosolvent and the effect was pronounced at relatively high values of Xorg for the dipolar aprotic cosolvents. This was attributed to a greater degree of destabilisation of the initial state as compared to the transition state with increasing mole fraction of the cosolvent. The In ks vs. 1/εs plots (ks is the rate constant and εs, the bulk relative permittivity) showed marked dependence on the nature of the cosolvents; the gradients of such plots generally increased with increasing dipole moment of the cosolvent molecules, indicating thereby that the solvation of the initial state and the transition state of the substrate is governed by the ion-dipole interactions between the water and cosolvent molecules. The relative transfer free energy of activation, [ΔΔGt≠](s←w), decreased linearly with Xorg for all mixed-solvent media, indicating that the preferential solvation effect is not significant. The activation enthalpy and entropy vs. Xorg plots displayed extrema suggesting that these thermodynamic parameters are sensitive to the structural changes in the bulk solvent phase. The solvent effects on ΔH≠ and ΔS≠ are mutually compensatory

Kinetics & Mechanism of Hydrolysis of cis-(Bromo) bis (ethylenediamine) (2-aminothiazole)cobalt(III) Cation

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Kinetics and mechanism of hydrolysis of cis-chlorobis(ethylenediamine)-(imidazole)cobalt(III) and cis-bromobis(ethylenediamine)(imidazole)cobalt(III) cations

The kinetics of hydrolysis of cis-[CoX(imH)(en)2]2+(imH = imidazole; en = ethylenediamine; X = Cl or Br) cations have been investigated in perchlorate medium of I= 0.3 mol dm-3. In the range pH 0.5-5.7 the rate law for aquation takes the form -dln[CoIII]/dt=k1+k2KNH[H+]-1 where k1 and k2 are the aquation rate constants of [CoX(en)2(imH)]2+ and [CoX(im)(en)2]+ respectively and KNH is the acid dissociation constant of the co-ordinated imidazole. At 50 ° C the values of k1,k2KNH, ΔH‡, and ΔS‡ for the k1 path are (1.21 ± 0.02)× 10-5 s-1, (4.95 ± 0.11)× 10-11 mol dm-3 s-1, 92.3 ± 1.2 kJ mol-1, -54 ± 3 J K-1 mol-1 for the chloro-, and (5.52 ± 0.10)× 10-5 s-1, (33.4 ± 0.7)× 10-11 mol dm-3 s-1, 94.5 ± 0.3 kJ mol-1, and -34 ± 1 J K-1 mol-1 for the bromo-complex respectively. Values of k2 obtained from the base-hydrolysis studies are (1.28 ± 0.17)× 10-2 and (2.46 ± 0.22)× 10-2 s-1 at 31.8 °C for the chloro- and bromo-complexes respectively, and the imido-complex [CoCl(im)(en)2]+ also undergoes second-order base hydrolysis with a rate constant of 5.1 ± 1.0 dm3 mol-1 s-1 at the same temperature. The labilizing action of imidazole and its conjugate base on the Co-X bond appears to be comparable to that of pyridine and hydroxide respectively. Co-ordinated imidazole is 105 times stronger as an acid than free imidazole. The sulphate- and mercury(II)-catalysed aquations of both the substrates have also been studied. The value of kip/k1, where kip and k1 are the rate constants of aquation of [CoX(imH)(en)2]2+, [SO4]2-and [CoX(imH)(en)2]2+ species respectively, is 2.3 ± 0.2 at 60 °C for X = Cl and 4.6 ± 0.1 at 50 °C for X = Br. The mercury(II)-catalysed aquation follows second-order kinetics, -dln[CoIII]/dt=kHg[Hg2+] : at 30.5 °C the rate constant (kHg]) and activation enthalpy and entropy are (3.48 ± 0.03)× 10-2 dm3 mol-1 s-2, 68.4 ± 0.7 kJ mol-1. and -48 ± 2 J K-1 mol-1for the chtoro- and 12.4 ±0.5 dm3 mol-1s-1, 53.4 ± 0.4 kJ mol-1, and -48 ± J K-1 mol-1 for the bromo-complex respectively

Evidence of 1D behaviour of He4^4 confined within carbon-nanotube bundles

We present the first low-temperature thermodynamic investigation of the controlled physisorption of He$^{4}$ gas in carbon single-wall nanotube (SWNT) samples. The vibrational specific heat measured between 100 mK and 6 K demonstrates an extreme sensitivity to outgassing conditions. For bundles with a few number of NTs the extra contribution to the specific heat, C$_{ads}$, originating from adsorbed He$^{4}$ at very low density displays 1D behavior, typical for He atoms localized within linear channels as grooves and interstitials, for the first time evidenced. For larger bundles, C$_{ads}$ recovers the 2D behaviour akin to the case of He$^{4}$ films on planar substrates (grafoil).Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

EFFECT OF SULPHUR DIOXIDE ON GROWTH, CHLOROPHYLL AND SULPHUR CONTENTS OF TOMATO (SOLANUM LYCOPERSICUM L.)

The direct toxic effect of atmospheric pollutant such as sulphur dioxide on plants has been well documented. It is essentially a potent phytotoxic gas and its toxicity to plant is manifested in typical chronic or acute foliar symptom injury. The mode and extent of damage caused by this pollutant to tomato has not been precisely and systematically studied. Under such circumstances, the present investigation was undertaken under simulating condition to find out the possible extent of adaptability of tomato in SO2 emission of our state. The effect of varying levels of sulphur dioxide (0.25, 0.5 and 1.0 ppm) fumigated for 1 hour, 2 hours and 3 hours under simulated conditions on tomato revealed that the important traits like leaf number, leaf area, fresh weight, dry weight and chlorophyll content in leaves were adversely affected, the latter treatment (SO2 1.0 ppm with 3 hours exposure) being more uninnocuous in this regards. However, no significant variation was seen amongst the treatments in respect of tissue fresh and dry weight when compared with that of control (ambient SO2). On the other hand, sulphur content in tissues increase progressively with increasing levels of SO2 and time of fumigation and the variation observed within treatments was significant to each other. It is suggested that the lowest concentration of SO2 (0.25 ppm) used in this study is more than sufficient to bring about a significant changes in most of the parameters studied

Computational-Mechanism Design: A Call to Arms

Game theory has developed several powerful tools for analyzing decision making in systems composed of multiple autonomous actors. Given this fact, AI practitioners would like to exploit these tools when building software systems containing multiple agents. However, to do this, the tools must be tailored to computational settings. To this end, the authors provide an overview of computational-mechanism design, which deals with the application of economic principles in computer systems design. Moreover, because many complex systems are inherently distributed, they also present initial results from the relatively new field of distributed-computational-mechanism design and outline the key challenges involved in making the ideas practicable.Engineering and Applied Science

A hospital-based study of severe anemia in adults in Eastern India

Background: Anemia remains a crucial health problem in developing countries. Cardiac compromise and fatal complications usually occur at Hb of <5g/dL. The aim of the study was to determine possible etiologic and clinical profile in adult patients with very severe anemia (Hb of <5g/dL).Methods: A prospective observational study was conducted in a teaching hospital of Odisha over a period of 12months. A total of 70 patients of both men and non-pregnant women admitted to the medicine wards were included after exclusion. Detailed history, clinical examination and investigation findings were recorded. Independent ‘t’ test, Wilcoxon rank sum test, Pearson chi-square test and Fisher exact test were used as applicable, to compare the variables.Results: The mean Hb (g/dL) was 3.73 ±0.85 and the mean age of the study group was 53.34±17.75years. No significant difference was observed in the severity of anemia between the female (mean Hb of 3.56±0.93) and male patients (mean Hb of 3.87±0.77) (p=0.130). The most frequent etiology found was absolute iron deficiency (44.3%, n=31) and mostly (41.9%) found in the age group of ≥65years (p<0.001). Congestive cardiac failure was found in 20% (n=14) of patients and majority of patients (64.2%, n=9) were males (p<0.001).Conclusions: Iron deficiency is the principal cause of very severe anemia in adults rather than malignancy or anemia of chronic disease and only about one fourth of patients develop heart failure even with very severe anemia