Identification and purification of tRNAs containing N6-(delta 2-isopentenyl) adenosine using antibodies specific for N6-(delta-isopentenyl) adenosine

Antibodies specific for the modified nucleoside N6-(delta 2-isopentenyl) adenosine (i6A) were employed to identify the tRNAs containing i6A from an unfractionated tRNA mixture by a nitrocellulose filter binding assay. When radioactive aminoacyl-tRNAs were incubated with i6A-specific antibodies and filtered through nitrocellulose membrane filters, the tRNAs possessing i6A (tRNAtyr and tRNAser) remained on the filters. tRNAarg and tRNAlys which do not contain i6A showed no binding. This finding will be useful as a very simple and rapid assay of such RNAs under a variety of conditions. Purification of i6A containing tRNAs from an unfractionated tRNA mixture was achieved by affinity chromatography of the tRNAs on an i6A antibody-Sepharose column. Nonspecific binding of tRNAs to the column was avoided by the use of purified antibodies.

Partial Flow Sensitivity

Compiler optimizations need precise and scalable analyses to discover program properties. We propose a partially flow-sensitive framework that tries to draw on the scalability of flow-insensitive algorithms while providing more precision at some specific program points. Provided with a set of critical nodes — basic blocks at which more precise information is desired — our partially flow-sensitive algorithm computes a reduced control-flow graph by collapsing some sets of non-critical nodes. The algorithm is more scalable than a fully flow-sensitive one as, assuming that the number of critical nodes is small, the reduced flow-graph is much smaller than the original flow-graph. At the same time, a much more precise information is obtained at certain program points than would had been obtained from a flow-insensitive algorithm.

OOCs, Partial Relative Difference Families and a Conjecture of Golomb

The cyclic difference sets constructed by Singer are also examples of perfect distinct difference sets (DDS). The Bose construction of distinct difference sets, leads to a relative difference set. In this paper we introduce the concept of partial relative DDS and prove that an optical orthogonal code (OOC) construction due to Moreno et. al., is a partial relative DDS. We generalize the concept of ideal matrices previously introduced by Kumar and relate it to the concepts of this paper. Another variation of ideal matrices is introduced in this paper: Welch ideal matrices of dimension n by (n - 1). We prove that Welch ideal matrices exist only for n prime. Finally, we recast an old conjecture of Golomb on the Welch construction of Costas arrays using the concepts of this paper. This connection suggests that our construction of partial relative difference sets is in a sense, unique

LZW Based Distance Measures for Spoken Language Identification

We present a new approach to spoken language modeling for language identification (LID) using the Lempel-Ziv-Welch (LZW) algorithm. The LZW technique is applicable to any kind of tokenization of the speech signal. Because of the efficiency of LZW algorithm to obtain variable length symbol strings in the training data, the LZW codebook captures the essentials of a language effectively. We develop two new deterministic measures for LID based on the LZW algorithm namely: (i) Compression ratio score (LZW-CR) and (ii) weighted discriminant score (LZW-WDS). To assess these measures, we consider error-free tokenization of speech as well as artificially induced noise in the tokenization. It is shown that for a 6 language LID task of OGI-TS database with clean tokenization, the new model (LZW-WDS) performs slightly better than the conventional bigram model. For noisy tokenization, which is the more realistic case, LZW-WDS significantly outperforms the bigram technique

Collocated and Distributed STBCs with Partial Interference Cancellation Decoding, Part I: Full-Diversity Criterion

Low complexity decoders called Partial Interference Cancellation (PIC) and PIC with Successive Interference Cancellation (PIC-SIC), which include the Zero Forcing (ZF) and ZF-SIC receivers as special cases, were given by Guo and Xia along with sufficient conditions for a Space-Time Block Code (STBC) to achieve full diversity with PIC/PIC-SIC decoding for point-to-point MIMO channels. In Part-I of this two part series of papers, we give new conditions for an STBC to achieve full diversity with PIC and PIC-SIC decoders, which are equivalent to Guo and Xia's conditions, but are much easier to check. We then show that PIC and PIC-SIC decoders are capable of achieving the full cooperative diversity available in wireless relay networks and give sufficient conditions for a Distributed Space-Time Block Code (DSTBC) to achieve full diversity with PIC and PIC-SIC decoders. In Part-II, we construct new low complexity full-diversity PIC/PIC-SIC decodable STBCs and DSTBCs that achieve higher rates than the known full-diversity low complexity ML decodable STBCs and DSTBCs.

Collocated and Distributed STBCs with Partial Interference Cancellation Decoding, Part II: Code Construction

In this second part of a two part series of papers, we construct a new class of Space-Time Block Codes (STBCs) for point-to-point MIMO channel and Distributed STBCs (DSTBCs) for the amplify-and-forward relay channel that give full-diversity with Partial Interference Cancellation (PIC) and PIC with Successive Interference Cancellation (PIC-SIC) decoders. The proposed class of STBCs include most of the known full-diversity low complexity PIC/PIC-SIC decodable STBCs as special cases. We also show that a number of known full-diversity PIC/PIC-SIC decodable STBCs that were constructed for the point-topoint MIMO channel can be used as full-diversity PIC/PIC-SIC decodable DSTBCs in relay networks. For the same decoding complexity, the proposed STBCs and DSTBCs achieve higher rates than the known low decoding complexity codes. Simulation results show that the new codes have a better bit error rate performance than the low ML decoding complexity codes available in the literature.

Variation of the partial thermodynamic properties of oxygen with composition in YBa2Cu3O7−δ

The variation of equilibrium oxygen potential with oxygen concentration inYBa 2Cu3O7-δhas been measured in the temperature range of 773 to 1223 K. For temperatures up to 1073 K, the oxygen content of theYBa 2Cu3O7-δsample, held in a stabilized-zirconia crucible, was altered by coulometric titration. The compound was in contact with the electrolyte, permitting direct exchange of oxygen ions. For measurements above 1073 K, the oxide was contained in a magnesia crucible placed inside a closed silica tube. The oxygen potential in the gas phase above the 123 compound was controlled and measured by a solid-state cell based on yttria-stabilized zirconia, which served both as a pump and sensor. Pure oxygen at a pressure of 1.01 × 105 Pa was used as the reference electrode. The oxygen pressure over the sample was varied from 10-1 to 105 Pa. The oxygen concentrations of the sample equilibrated with pure oxygen at 1.01 × 105 Pa at different temperatures were determined after quenching in liquid nitrogen by hydrogen reduction at 1223 K. The plot of chemical potential of oxygen as a function of oxygen non-stoichiometry shows an inflexion at δ ∼ 0.375 at 873 K. Data at 773 K indicate tendency for phase separation at lower temperatures. The partial enthalpy and entropy of oxygen derived from the temperature dependence of electromotive force (emf ) exhibit variation with composition. The partial enthalpy for °= 0.3, 0.4, and 0.5 also appears to be temperature dependent. The results are discussed in comparison with the data reported in the literature. An expression for the integral free energy of formation of YBa2Cu3O6.5 is evaluated based on measurements reported in the literature. By integration of the partial Gibbs’ energy of oxygen obtained in this study, the variation of integral property with oxygen concentration is obtained at 873 K.

Gibbs energy of formation of CaCu3Ti4O12 and phase relations in the system CaO-CUO/CU2O-TiO2

he standard Gibbs energy of formation of CaCu3Ti4O12 (CCTO) from CaTiO3, CuO and TiO2 has been determined as a function of temperature from 925 to 1350 K using a solid-state electrochemical cell with yttria-stabilized zirconia as the solid electrolyte. Combining this result with information in the literature on CaTiO3, the standard Gibbs energy of formation of CCTO from its component binary oxides, CaO, CuO and TiO2, has been obtained: View the MathML source (CaCu3Ti4O12)/J mol−1 (±600) = −125231 + 6.57 (T/K). The oxygen chemical potential corresponding to the reduction of CCTO to CaTiO3, TiO2 and Cu2O has been calculated from the electrochemical measurements as a function of temperature and compared on an Ellingham diagram with those for the reduction of CuO to Cu2O and Cu2O to Cu. The oxygen partial pressures corresponding to the reduction reactions at any chosen temperature can be read using the nomograms provided on either side of the diagram. The effect of the oxygen partial pressure on phase relations in the pseudo-ternary system CaO–CuO/Cu2O–TiO2 at 1273 K has been evaluated. The phase diagrams allow identification of secondary phases that may form during the synthesis of the CCTO under equilibrium conditions. The secondary phases may have a significant effect on the extrinsic component of the colossal dielectric response of CCTO.

Identification and optimization of ammonia reactors through hybrid simulation

A hybrid simulation technique for identification and steady state optimization of a tubular reactor used in ammonia synthesis is presented. The parameter identification program finds the catalyst activity factor and certain heat transfer coefficients that minimize the sum of squares of deviation from simulated and actual temperature measurements obtained from an operating plant. The optimization program finds the values of three flows to the reactor to maximize the ammonia yield using the estimated parameter values. Powell's direct method of optimization is used in both cases. The results obtained here are compared with the plant data.

Carnatic music analysis: Shadja, swara identification and rAga verification in AlApana using stochastic models

We analyze the AlApana of a Carnatic music piece without the prior knowledge of the singer or the rAga. AlApana is ameans to communicate to the audience, the flavor or the bhAva of the rAga through the permitted notes and its phrases. The input to our analysis is a recording of the vocal AlApana along with the accompanying instrument. The AdhAra shadja(base note) of the singer for that AlApana is estimated through a stochastic model of note frequencies. Based on the shadja, we identify the notes (swaras) used in the AlApana using a semi-continuous GMM. Using the probabilities of each note interval, we recognize swaras of the AlApana. For sampurNa rAgas, we can identify the possible rAga, based on the swaras. We have been able to achieve correct shadja identification, which is crucial to all further steps, in 88.8% of 55 AlApanas. Among them (48 AlApanas of 7 rAgas), we get 91.5% correct swara identification and 62.13% correct R (rAga) accuracy.