Strategic management researchers often encounter problems obtaining objective measures of selected aspects of organizational performance that are reliable and valid. With privately-held firms, such data are frequently unavailable. With conglomerate business units, all or parts of such data are inextricab(y interwoven with corporafe-wide data. This paper examines the usefulness ofsubjective performance measures, obtained from top management teams, when problems are encountered in obtaining accurate performance data. 0 143-2095/84/030265-09$01 .OO
Hyperpolarization-activated cation currents, termed If, Ih, or Iq, were initially discovered in heart and nerve cells over 20 years ago. These currents contribute to a wide range of physiological functions, including cardiac and neuronal pacemaker activity, the setting of resting potentials, input conductance and length constants, and dendritic integration. The hyperpolarization-activated, cation nonselective (HCN) gene family encodes the channels that underlie Ih. Here we review the relation between the biophysical properties of recombinant HCN channels and the pattern of HCN mRNA expression with the properties of native Ih in neurons and cardiac muscle. Moreover, we consider selected examples of the expanding physiological functions of Ih with a view toward understanding how the properties of HCN channels contribute to these diverse functional roles.
This study examined the moderating role of planning sophistication on the strategy-performance relationship in 97 manufacturing firms representing 60 different industries. Cluster analysis was used to group the firms according to their strategic orientation. Five groups emerged. Significant differences in performance across selected groups were found establishing a 'baseline' strategy-performance relationship. Strategic orientations emphasizing product innovation or those incorporating 'eficiency' and 'differentiation' patterns of strategic behavior were associated with significantly higher performance levels than two other groups. The nature of each firm's planning process was then introduced via a two-way ANOVA procedure to determine if 'process sophistication' moderated the strategy-performance 'baseline'. Level of planning sophistication was found to significantly moderate the previously established strategy-performance baseline.
HCN cation channel mRNA expression was determined in the rabbit heart and neonatal and adult rat ventricle using RNase protection assays. In the rabbit SA node, the dominant HCN transcript is HCN4, representing >81% of the total HCN message. HCN1 is also expressed, representing >18% of the total HCN mRNA. Rabbit Purkinje fibers contained almost equal amounts of HCN1 and HCN4 transcripts with low levels of HCN2, whereas rabbit ventricle contained predominantly HCN2. The SA node contained 25 times the total HCN message of Purkinje fibers and 140 times the total HCN message of ventricle. No reports of hyperpolarization-activated current (If) exist in rabbit Purkinje fibers, and we could not record If in rabbit ventricular myocytes. To investigate the possible role of isoform switching in determining the voltage dependence of If, we determined the prevalence of HCN isoforms in neonatal and adult rat ventricle. We had previously determined the threshold for activation of If to be approximately -70 mV in neonatal rat ventricle and -113 mV in adult rat ventricle. In both neonatal and adult rat ventricle, only HCN2 and HCN4 transcripts are present. The ratio of HCN2 to HCN4 is approximately 5:1 in the neonate and 13:1 in the adult. Taken together, these results suggest that different cardiac regions express different isoforms of the HCN family. The HCN1 and HCN4 isoforms are most closely associated with a depolarized threshold for If activation, whereas the HCN2 isoform is associated with a more negative activation curve.
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