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A consistent set of statistical-model input parameters, validated by analysis of various independent data, makes possible the assessment of an $$\alpha $$ α -particle optical model potential [Phys. Rev. C 90, 044612 (2014)] also for nucleon-induced $$\alpha $$ α -emission within the $$A \sim 60$$ A ∼ 60 mass-number range. The advantage of recent data for low-lying states feeding is taken as well. Consideration of additional reaction channels leading to increase of the $$\alpha $$ α -emission beyond the statistical predictions has concerned the pickup direct interaction and Giant Quadrupole Resonance similar features.

The cross sections of the $^{59}\mathrm{Co}(d,p)^{60m,g}\mathrm{Co},^{51}\mathrm{V}(d,p)^{52}\mathrm{V}$, and ${}^{\mathrm{nat}}\mathrm{V}{(d,xn)}^{51}\mathrm{Cr}$ reactions were accurately measured at the Soreq Applied Research Accelerator Facility in the energy range 2.7--5.4 MeV. The obtained results together with other data, available in the same region of the nuclear chart, were used for verifying the theoretical models. The consistent theoretical model calculation successfully reproduces the experimental results.

An extended discussion of the deuteron-induced reactions concerning full parametrization procedure as well as consideration of the theoretical models associated to the deuteron interaction process is carried out. The key role of direct interactions, i.e., breakup, stripping and pick-up processes is stressed out by comparison of the available experimental data with theoretical and evaluation predictions.

Further high-precision measurements of α-induced reactions on 64Zn, 108Cd, 113,115In, 121,123Sb, and 191,193Ir below the Coulomb barrier have been considered within statistical-model analyses using the previous optical potential. The focus of the work is on eventual uncertainties and/or systematic errors of the OMP assessment at low energies due to the limits in the knowledge of the rest of nuclear model parameters. These parameters were analyzed anyway in advance using independent data, particularly γ-ray strength functions, including their uncertainties.

Background: Further studies of high-precision measurements of alpha-induced reaction data below the Coulomb barrier have still raised questions about the alpha-particle optical model potential (OMP) within various mass ranges, i.e. for 64Zn, 108Cd, 113,115In, 121,123Sb, and 191,193Ir target nuclei. Purpose: The accuracy as well as eventual uncertainties and/or systematic errors of using a previous optical potential are much better considered by analysis of such accurate data. Method: Statistical model (SM) calculations of the (alpha,x) reaction cross sections have been carried out using model parameters which were previously obtained by analyzing independent data, particularly gamma-ray strength functions, and taking into account their uncertainties and questions of extrapolation for nuclei without similar data. Results: Consistent description of the recent alpha-induced reaction data is provided by the above-mentioned optical potential with no empirical rescaling factors of either its own parameters or the gamma and/or nucleon widths. Effects of still uncertain SM parameters on calculated alpha-induced reaction cross sections and conclusions on the alpha-OMP can be now discussed due to unprecedented precision of the new data. Conclusions: The alpha-particle optical potential has been confirmed at incident energies below the Coulomb barrier using statistical-model parameters validated through a former analysis of independent data., Comment: 14 pages, 6 figures

Background: Challenging questions of the $\alpha$-particle optical-model potential (OMP) are still pointed out by recent high-precision measurements of $\alpha$-induced reaction data below the Coulomb barrier. Moreover, the reliability of a previous OMP for $\alpha$-particles on nuclei within the mass number range 45$\leq$$A$$\leq$209 has been recently proved for emitted $\alpha$ particles as well, but only in the case of proton-induced reactions on Zn isotopes [Phys. Rev. C {\bf 91}, 064611 (2015), Paper I]. Purpose: Analysis of most recent $(\alpha,\gamma)$ reaction data for Ge and Zr isotopes, which provides an additional validation of the above-mentioned potential, is related to a further account of $\alpha$-particle emission in neutron-induced reactions on Zr isotopes, at the same time with a suitable description of all competitive processes. Methods: A consistent parameter set, established or validated by independent analysis of recent various data, particularly $\gamma$-ray strength functions, have been involved within model calculation of the $(\alpha,\gamma)$ as well as $(n,\alpha)$ reaction cross sections. The latter are part of the whole analysis of the neutron activation of Zr isotopes, in order to avoid any error compensation or latent ambiguity. Results: The aforesaid potential provides a consistent description of recent $\alpha$-induced reaction data with no empirical rescaling factors of the $\gamma$ and/or nucleon widths. On the other hand, its use leads to underestimated predictions of the pre-equilibrium emission and statistical models for the $(n,\alpha)$ reaction cross sections. Conclusions: An optical potential with a volume imaginary component seems to be needed to describe the low-energy $\alpha$-particle evaporation, while only surface absorption occurs in $\alpha$-induced reactions at similar energies.

The high–precision recent measurements of α-particle induced–reaction data below the Coulomb barrier make possible the understanding of actual limits and possible improvement of the α-particle optical–model potentials. An updated optical potential is thus provided for α-particles on nuclei within the mass number range 45 ⩽ A ⩽ 197 , below the Coulomb barrier. The results that could be obtained by using this potential within analysis of the α-particle emission in fast–neutron induced reaction at low energies are moreover discussed.

A competition of the low-energy Coulomb excitation (CE) with the compound nucleus (CN) formation in α-induced reactions below the Coulomb barrier has recently been assumed in order to make possible the description of the latter as well as the α-particle emission by the same optical model (OM) potential. However, we show in the present work that the corresponding partial waves and integration radii provide evidence for the distinct account of the CE cross section and OM total-reaction cross section σR. Thus the largest contribution to CE cross section comes by far from partial waves larger than the ones contributing to the σR values. Finally, effects of statistical model parameters are comparatively discussed.

Background: Recent high-precision measurements of alpha-induced reaction data below the Coulomb barrier have pointed out questions of the alpha-particle optical-model potential (OMP) which are yet open within various mass ranges. Purpose: The applicability of a previous optical potential and eventual uncertainties and/or systematic errors of the OMP assessment at low energies can be further considered on this basis. Method: Nuclear model parameters based on the analysis of recent independent data, particularly gamma-ray strength functions, have been involved within statistical model calculation of the (alpha,x) reaction cross sections. Results: The above-mentioned potential provides a consistent description of the recent alpha-induced reaction data with no empirical rescaling factors of the and/or nucleon widths. Conclusions: A suitable assessment of alpha-particle optical potential below the Coulomb barrier should involve the statistical-model parameters beyond this potential on the basis of a former analysis of independent data., Comment: 12 pages, 8 figures. Updated citations. Minor correction

Recent measurements of $\ensuremath{\alpha}$-particle induced reactions on the $^{64}\mathrm{Zn}$ nucleus, below and around the Coulomb barrier, are analyzed simultaneously with $\ensuremath{\alpha}$-particle emission at similar energies in proton-induced reactions on Zn isotopes. All open reaction channels, particularly the $\ensuremath{\gamma}$ decay, are calculated using consistent input parameters. Additionally, we check a previous optical-model potential for $\ensuremath{\alpha}$ particles on nuclei within the mass number range $45\ensuremath{\le}A\ensuremath{\le}209$ [Avrigeanu et al., Phys. Rev. C 90, 044612 (2014)] and prove its correctness in the outgoing channel at least for the present case involving $^{64}\mathrm{Zn}$ and nearby nuclei. The reliability of this potential for incident as well as emitted low-energy $\ensuremath{\alpha}$ particles is supported by the successful reproduction of high-precision measured data, using no empirical rescaling factor of the $\ensuremath{\gamma}$ and/or particle widths.

An extended analysis of the nuclear reaction mechanisms involved within deuteron interaction with nuclei, namely the breakup, stripping, pick-up, pre-equilibrium emission, and evaporation from fully equilibrated compound nucleus, is presented in order to highlight the importance of the direct mechanisms still neglected in the analysis of deuteron-induced surrogate reactions. Particularly, the dominance of the breakup mechanism at low energies around the Coulomb barrier should be considered in the case of (d,x) surrogate reactions on actinide target nuclei.

An updated optical potential is thus provided for α-particles on nuclei within the mass number range 45≤A≤209, below the Coulomb barrier (B), on the basis of recent high-precision measurements of α-particle induced reaction data below B that made possible the understanding of actual limits and possible improvement of the α-particle optical-model potentials. The main revision concerns actually only the surface imaginary potential depth at the lowest α-particle energies well below B, and in fact only for the mass range above A∼130. A further regional point is the underestimation of reaction cross sections for the rare-earth nuclei by using the spherical optical potential unless a 7% larger value of the surface imaginary potential radius is taken into account. Involvement of this potential for further description of both the scattering and α-particles induced reactions is moreover discussed in the present work, of equal interest for nuclear astrophysics and nuclear technology for fusion devices.

The consequences which the suitable consideration of direct interaction, namely the breakup, stripping and pick-up processes, may have for the analysis of the deuteron surrogate reacions as well as for studies of nuclear-level density models on the basis of nucleon spectra analysis in deuteron-induced reactions are discussed. An increased attention is paid to the deuteron breakup which is the dominant mechanism for the interaction processes at low incident energies around Coulomb barrier, particularly on actinides.

The high precision of recent measurements for low-energy α-particle elastic-scattering as well as induced-reaction data makes possible the understanding of actual limits and possible improvement of the global optical model potentials parameters. Involvement of recent optical potentials for reliable description of both the elastic scattering and emission of α-particles, of equal interest for nuclear astrophysics (NA) and nuclear technology (NT) for fusion devices, is discussed in the present work.

Different energy dependences of the single-hole and excited-particle state densities, of Fermi-gas model type and a linear dependence respectively, are adopted in accordance with recent proofs of accurate shell-model Hamiltonian eigenvalues. The respective different values at the Fermi level also make possible both the correct prediction of the bound nucleon number, for a Fermi energy value of 40 MeV, and the agreement with the average neutron resonance spacing data. An attempt to distinguish between the surface effects and the influences attributable to the energy dependence of the single-particle state density is made within the geometry-dependent hybrid model of the pre-equilibrium emission. Comparisons with the large amount of data existing for fast-neutron reactions on the 51V and 56Fe target nuclei at incident energies up to 20 MeV support the model assumptions.

Recent accurate data obtained for the isomeric cross section of the $^{197}$Au$(n,2n)$ reaction provide a valuable opportunity to consider the question of the effective moment of inertia of the nucleus within a local consistent model analysis of all available reaction data for the $^{197}$Au target nucleus. Thus, a definite proof of a moment of inertia equal to that of the rigid--body has been obtained for $^{196}$Au nucleus while an inference of the half rigid--body value is suggested for the $^{194}$Ir nucleus. The usefulness of further measurements at incident energies up to $\ge$40 MeV has also been proved., 5 pages, 5 figures

The n TOF collaboration operates a Total Absorption Calorimeter (TAC) [1] for measuring neu- tron capture cross-sections of low-mass and/or radioactive samples. The results obtained with the TAC have led to a substantial improvement of the capture cross sections of 237Np and 240Pu [2]. The experience acquired during the rst measurements has allowed us to optimize the performance of the TAC and to improve the capture signal to background ratio, thus opening the way to more complex and demanding measurements on rare radioactive materials. The new design has been reached by a series of detailed Monte Carlo simulations of complete experiments and dedicated test measurements. The new capture setup will be presented and the main achievements highlighted.

Novel measurements of ({alpha},{gamma}) and ({alpha},n) reaction cross sections on the target nucleus {sup 151}Eu, close to the reaction thresholds, support the choice of recently proposed parameters of the {alpha}-particle optical model potential below the Coulomb barrier. A better understanding of the {alpha}-particle optical potential at these energies leads to a statistical model analysis of additional partial cross sections that were measured but not considered within a former model analysis. On this basis we have tentatively assigned a modified J{sup {pi}}=9{sup -} spin and parity to the 22.7-h isomer in {sup 154}Tb.

International audience; The "Neutrons for Science" (NFS) facility will be a component of SPIRAL‐2, the future accelerator dedicated to the production of very intense radioactive ion beams, under construction at GANIL in Caen (France). NFS will be composed of a pulsed neutron beam for in‐flight measurements and irradiation stations for cross‐section measurements and material studies. Continuous and quasi‐monokinetic energy spectra will be available at NFS respectively produced by the interaction of deuteron beam on thick a Be converter and by the 7Li(p,n) reaction on a thin converter. The flux at NFS will be up to 2 orders of magnitude higher than those of other existing time‐of‐flight facilities in the 1 MeV to 40 MeV range. NFS will be a very powerful tool for physics and fundamental research as well as applications like the transmutation of nuclear waste, design of future fission and fusion reactors, nuclear medicine or test and development of new detectors.

An analysis of all available $\ensuremath{\alpha}$-particle-induced reaction cross sections on nuclei within the mass number range $121\ensuremath{\leqslant}A\ensuremath{\leqslant}197$, below the Coulomb barrier, is carried out. This analysis leads to an optical potential that describes the $\ensuremath{\alpha}$-particle elastic scattering at low energies as well and both elastic-scattering and reaction data for $45\ensuremath{\leqslant}A\ensuremath{\leqslant}124$. The energy dependence of the surface imaginary potential depth is proved to be essential for understanding $\ensuremath{\alpha}$-particle interaction behavior below the Coulomb barrier.

New results of $(\ensuremath{\alpha},\ensuremath{\gamma})$ and $(\ensuremath{\alpha},n)$ reaction cross section measurements close to the reaction thresholds support the setting up of recent parameters of the $\ensuremath{\alpha}$-particle optical model potential (OMP) below the Coulomb barrier. Particular features of the $\ensuremath{\alpha}$-particle optical potential at energies below the Coulomb barrier explain the failure of using the OMP parameters obtained by analysis of only $\ensuremath{\alpha}$-particle elastic scattering at higher energies.

The results of two recent papers concerning ({alpha},{gamma}) and ({alpha},n) reaction cross sections close to the reaction thresholds are discussed with regard to predictions of a recent {alpha}-particle regional optical potential. It is found that the new measured cross sections are rather well described especially for the dominant reaction channels. Particular features of the {alpha}-particle optical potential at energies below the Coulomb barrier explain the failure of a former regional potential obtained by analysis of {alpha}-particle elastic scattering alone at higher energies. Additional limitations of statistical model calculations for minor reaction channels are also discussed.

Thermal and chemical stability of pentoxifylline from modified release tablets were studied. This experimental study observed the influence of temperature and humidity on the stability of pentoxifylline from the proposed formulations. The paper describes the HPLC determination of pentoxifylline from new controlled release tablets with hydrophilic matrix (HPMC, HPC, HEC). A C18 column with a mobile phase containing water : acetonitrile 70:30 (V/V) and UV detection at 280 nm was used. The "in vitro" dissolution test was carried out regarding the officinal stipulations of USP; the machine nr.2 was used (with paddles); as dissolution environment 1000 ml water, a constant temperature of 37 plusmn 0.5degC was kept. In all experiences, the rotation speed was 50 rpm. The studied tablets were kept in the stability chamber at a temperature of 40 plusmn 2degC and a relative humidity of 75 plusmn 5%. At different time intervals (a month, three months, six months), samples were prelevated to accomplish the dissolution test and the quantitative determination of pentoxifylline. From the evaluation of the experimental results, we observed the stability of pentoxifylline from all the prepared tablets.

Consistent pre-equilibrium emission and statistical model calculations of fast neutron induced reaction cross sections are used to validate nuclear level densities for excitation energies up to 40 MeV in the mass regionA ≃50. A “composed” level density approach has been employed by using the back-shifted Fermi gas model for excitation energies lower than 12 MeV and a realistic analytical formula for higher excitations. In the transition region from the BSFG model range to that of full applicability of the realistic formula, an interpolation between the predictions of the two models is adopted. The interpolation rule, suggested by microscopic level density calculations, has been validated through the comparison of the calculated and experimental cross sections.

An analysis of the elastic scattering of deuterons on 6,7 Li, 27 Al, 54,56,58 Fe, 63,65 Cu, and 93 Nb for energies from 3 to 60MeV has been carried out using a semi-microscopic optical potential which consists of a Coulomb term, a real double-folding (DF) potential, a phenomenological imaginary potential and a spin-orbit component. No normalization constant was involved in this work for the DF real potential, in order to emphasize the effects of further corrections requested by a satisfactory description of the experimental data. Moreover, an empirical non-locality correction to the microscopic real potential has been added in the case of the d + 6 Li scattering. By taking into account also the dispersion correction, a good agreement of the experimental and semi-microscopic elastic scattering angular distribution has been obtained. The imaginary and spin-orbit potential parameters obtained by the semi- microscopic data analysis have been kept fixed within a second step of the present analysis, in order to obtain a full phenomenological optical potential needed for applications. As a global result, one may note differences of about 10-15% between the deuteron reaction cross sections corresponding to the present improved optical potential and those obtained using the default input parameters within the TALYS code, while enlarged changes are shown by the calculated elastic-scattering angular distributions. The differences with respect to the evaluated total reaction cross sections of the ACSELAM library are about 25-30%.

Experimental cross sections are compared with the results of calculations including all activation channels for the stable isotopes of Mn and Cu, for neutron incident energies below 20MeV as well as up to 40-50MeV. It results that within the former energy range, the model calculations are most sensitive to the parameters related to nuclei in the early stages of the reaction, while the model assumptions are better proved by analysis of the data in the latter energy range.

We show that the new experimental data reported by Galaviz et al. [Phys. Rev. C 71, 065802 (2005)] can be used to improve a previous optical potential global parameter set, employing the corresponding former local parameter basis as well as the parameter sets obtained through a similar analysis of the new data.

In order to reduce the deviation of calculated‐to‐experimental activity (C/E) following benchmark experiments with pure W irradiated by 14‐MeV neutrons, of interest for safety aspects and waste management of power plants, a detailed analysis of the activation cross sections was carried out using the computer codes EMPIRE‐II and TALYS as well as local parameter sets within the STAPRE‐H code. The sensitivity of the calculated cross sections to various model parameters is derived and discussed in connection with improving the C/E of the benchmark experiment.

An extended analysis of reaction mechanisms involved in deuterons interaction with target nuclei from 27Al till 231Pa, at incident energies up to 60 MeV, is presented. Increased attention is devoted to direct processes, concerning the breakup, stripping, and pickup contributions to the deuteron activation cross sections. Finally, the pre-equilibrium and evaporation cross sections, corrected for the initial flux leakage towards direct processes, have completed the deuteron interaction analysis. The overall agreement of the measured data and model calculations proves the correctness of nuclear mechanism description.

Excitation functions of the ${}^{58}\mathrm{Ni}{(n,p)}^{58}{\mathrm{Co}}^{m,g}$ reactions were measured in the energy range from 2 to 15 MeV. The energy dependence of the isomeric cross-section ratio $R={\ensuremath{\sigma}}_{m}/({\ensuremath{\sigma}}_{m}+{\ensuremath{\sigma}}_{g})$ is deduced from the measured data. The shape and magnitude of the ${R(E}_{n})$ function are described by model calculations using a consistent parameter set. Questions of the input level scheme were solved based on the accurate isomeric ratio measured at low energy region. The measured R-value prefers the mixing ratio value of $\ensuremath{-}2.3$ for the transition of the 52.8 keV state to the 24.9 keV state, over the $\ensuremath{-}0.33$ value. The transition has predominantly $E2$ multipolarity.

The experimental cold-fission yields for the systein 23'~(n,h ,f) are analyzed as function of the effective total excitation energy (TXE). The nuclear level density effect is taken into account at higher TXE, in order to benefit by the lower experimental data uncertainty as well as to avoid the quantitative account of the level densities close to fragment ground states. In this way the odd-even staggering which appears in the yields extrapolated at Zero excitatiori energy by using the level densities, vanishes. We conclude that the cold nuclear fragmentatioii theory including the dynamical model desciibes well the experimental data.

A set of global optical model parameters has been derived starting from alpha-particle elastic scattering with energies higher than 80 MeV where the continuous ambiguities in the optical model analyses are eliminated. The geometry and mass number dependence derived by Nolte et al.1 and the energy dependence found by Put and Paans2 were thus adopted. Moreover, variation of the imaginary well depth at lower energies has been adopted by taking into account results derived from the study of the elastic scattering on 90Zr2 and 24Mg3.

Studies of nucleosynthesis in evolving stars and Supernovae rely heavily on reaction cross sections computed by means on nuclear models. A broad range of nuclear parameters and even model assumptions are required in this respect, and the most elaborated evolution models still suffer from major both astrophysical and nuclear physics uncertainties1. The statistical model of nuclear reactions is largely used to calculate the host of unmeasured reaction rates involved in the modeling of neon, oxygen, and silicon burning. Especially non-explosive as well as explosive Si burning comprises a very complex pattern of nuclear reactions, when the full nuclear statistical equilibrium is reached between all the nuclear species of the medium resulting in the production of the iron peak nuclei. The accuracy of the calculated cross sections for nucleon and alpha-particle induced reactions on 1f 7/2 shell nuclei is discussed in this work.

Recent high-precision measurements α-particle elastic scattering and (α,x) reaction cross sections has motivated the extension of a previous semi-microscopic analysis for the mass-region 50

An extended analysis of the reaction mechanisms involved in the deuterons interaction with light and medium nuclei, 27Al and 63,65Cu, at incident energies from 3 to 60 MeV starting with elastic scattering until the evaporation from fully equilibrated compound system is presented. An increased attention is devoted to the breakup mechanism, all its components, the elastic, inelastic (fusion), and total breakup, being carefully analysed. Moreover, the corresponding stripping mechanism contribution to the (d, p) and (d, n) reaction cross sections through population of the discrete levels of the residual nuclei, was calculated. Finally, following the decay path, the pre-equilibrium and evaporation cross sections, corrected for the breakup and stripping decrease of the total reaction cross section, have completed the deuteron activation cross sections analysis. The overall agreement between the measured data and model calculations proves the correctness of nuclear mechanism description taken into account for the deuteron-nucleus interaction.

Correlations of the isotope effect for the (n,p) and (n,α) reaction cross sections at 14.7 MeV, and significant quantities of both the statistical and preequilibrium emission models are made by means of Hauser-Feshbach and Geometry-Dependent Hybrid calculated cross sections. The accuracy of the nuclear model predictions has been proved by extensive comparison to experimental fast neutron reactions data for the stable isotopes of Ti, V, Cr, Mn, Fe, Co and Ni. The calculated cross sections have been furthermore used to discuss the applicability of the Qgg — systematics of the deep inelastic collisions between complex nuclei to fast neutron reactions. Consequences of accurate low-lying discrete levels on confident statistical model calculations are analyzed and necessity of microscopical level schemes is pointed out.

The reaction 73Ge(16O,3n) at 52.0 MeV incident energy was used to populate excited states of 86Zr. Lifetimes of several of these states were determined with the aid of the recoil-distance Doppler-shift method. The resulting gamma ray transition probabilities are discussed in connection with the existing values in other Zr isotopes.

(n, p), (n, n'p) and (n,2n) reaction cross-sections for stable titanium isotopes in the energy range from threshold up to 20 MeV have been calculated. An improved prequilibrium approach, allowing an unitary use of preequilibrium and equilibrium emission parameters, has increased the agreement between calculated and experimental cross-sections.

The experimentally well known (n, p), (n, α) and (n, 2n) reaction excitation functions, from threshold to 20 MeV incident energy, and neutron and proton emission spectra at 14.8 MeV from54,56Fe targets are calculated in the frame of the Geometry-Dependent Hybrid pre-equilibrium emission model, including angular momentum and parity conservation, and the Hauser-Feshbach statistical model. Use of a consistent statistical model parameter set enables the validation of the pre-equilibrium emission model. Moreover, an enhanced pre-equilibrium emission from higher spin composite system states, associated with higher incoming orbital momenta, has been evidenced. Higher orbital momenta involved also in the emergent channels of the process are suggested by calculations of the residual nuclei level populations.

Mean lives and excitation energies of the lowest levels in 64 Ni, 66 Zn and 68 Zn were measured with the aid of the (α, α′γ) and (α, pγ) reactions. The γ-rays were detected in coincidence with the outgoing particles. The following mean lives were determined from DSA measurements: 400 ± 150 fs for the level at E x = 1.35 MeV in 64 Ni; 270 ± 100, 210 ± 110, 330 ± 200, 80 ± 70 fs for the levels at E x = 1.87, 2.45, 2.83, 2.94 MeV in 66 Zn, and 1300 ± 300, > 160, 600 ± 200 fs for the levels at E x = 1.08, 1.89 and 2.76 MeV in 68 Zn, respectively.

In order to study the role of myocardial hypertrophy and of the intramural tension as determinants of the increased voltage in concentric left ventricular hypertrophy, the amplitude of intracellular action potentials in frog and rat myocardium and of monophasic action potentials recorded in dogs by suction electrodes were studied. Increased amplitudes of intracellular action potentials were seen neither in experimental LVH in rats nor during stretch in frog and rat myocardium. The increased intramural tension in dog heart during norepinephrine perfusion or in heart-lung preparation during increased peripheral resistance does not increase the amplitude of monophasic action potentials. The abrupt hypertension induced by norepinephrine is an inadequate model for the study of the effect of increased intramural tension. The increase of the voltage in LVH cannot be accounted for by the increase of action potentials of each hypertrophied fibre. Many factors cooperate in producing increased voltage of LV in LVH.