A new CMOS balanced output transconductor is presented. The circuit is based on applying the dynamic biasing technique on the floating current source to extend its linearity range. The difference in the biasing currents is compensated to maintain the two output currents balanced by subtracting it at the output nodes. The proposed transconductor is suitable for high frequency applications requiring a wide dynamic range. Rail-to-rail operation is achieved with THD of −33.64 dB. The bandwidth achieved by the transconductor is 240 MHz, and the supply voltage used is ±1.5 V.

Decontamination of beef by spraying with solutions of lactic acid is common practice in North America and is to be permitted in the EU. Validation of each such treatment is necessary for HACCP purposes. The utility of validation by reference to reduction in numbers of Escherichia coli naturally present on beef is questioned. This is because reductions of E. coli generally might be greater than reductions of the main target organism, E. coli O157:H7, which can be more acid tolerant. To investigate the effects of lactic acid sprays on the two types of E. coli on beef surfaces, slices of beef with cut muscle, fat or membrane surfaces were prepared. The surfaces were inoculated with a five strain cocktail of acid-adapted E. coli O157:H7 or with a not-acid-adapted strain of E. coli at number of 5, 1 or −1 log cfu/cm2. Inoculated slices were not treated or were sprayed with water or 2% or 5% lactic acid at 0.5 ml/cm2. For each slice of lactic acid-treated meat the numbers of E. coli or E. coli O157:H7 recovered on agars that allowed resuscitation of injured cells or did not allow resuscitation were similar. The differences in the log mean numbers (log A) and in the log total numbers (N) of bacteria recovered from slices that were not treated or treated with acid were calculated. Differences in log A and N for bacteria recovered from slices treated with water or acid were calculated also. Means of the differences indicated that each acid treatment gave similar reductions in the numbers of E. coli or E. coli O157:H7. However, reductions were somewhat greater with 5% than with 2% lactic acid. The findings suggest that the E. coli or E. coli O157:H7 that survived acid treatments of meat surfaces were protected from exposure to injurious concentrations of undissociated acid. Consequently, strains of E. coli that are or are not relatively tolerant of acid conditions will be inactivated to similar extents by solutions of lactic acid applied to beef surfaces.

This paper considers first-order autoregressive panel model which is a
simple model for dynamic panel data (DPD) models. The generalized
method of moments (GMM) gives efficient estimators for these models.
This efficiency is affected by the choice of the weighting matrix which has
been used in GMM estimation. The non-optimal weighting matrices have
been used in the conventional GMM estimators. This led to a loss of
efficiency. Therefore, we present new GMM estimators based on optimal or
suboptimal weighting matrices. Monte Carlo study indicates that the bias
and efficiency of the new estimators are more reliable than the
conventional estimators.