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Objective: Heart rate asymmetry is a phenomenon in which the contribution of heart rate decelerations to short-term heart rate variability is greater than that of accelerations, and the contribution of accelerations to long-term and total variability is greater than that of decelerations. This has been established for short, stationary recordings, so our aim is to do it for long recordings. Approach: In this paper, we analyze heart rate asymmetry in 87 long, 24 h electrocardiogram Holter recordings from healthy people. We show that in the whole recording all types of asymmetry are observable, clear and highly statistically significant. To analyze the local changes of asymmetry in time, we analyzed the recordings by disjoint jumping windows of 300 beats. Main results: This analysis revealed that the local, averaged measures of all types of asymmetry also demonstrate its presence which is highly statistically significant. Additionally, we introduce in this paper a statistical test for asymmetry in a single long recording, as opposed to the current approach in which whole groups are tested. We do this by introducing the proportion of time spent in asymmetry for each recording and using it in the binomial tests. Significance: We found that for all the recordings most of the time is spent in asymmetry. [ABSTRACT FROM AUTHOR]

Deep convective updraft invigoration via indirect effects of increased aerosol number concentration on cloud microphysics is frequently cited as a driver of correlations between aerosol and deep convection properties. Here, we critically evaluate the theoretical, modeling, and observational evidence for warm- and cold-phase invigoration pathways. Though warm-phase invigoration is plausible and theoretically supported via lowering of the supersaturation with increased cloud droplet concentration in polluted conditions, the significance of this effect depends on substantial supersaturation changes in real-world convective clouds that have not been observed. Much of the theoretical support for cold-phase invigoration depends on unrealistic assumptions of instantaneous freezing and unloading of condensate in growing, isolated updrafts. When applying more realistic assumptions, impacts on buoyancy from enhanced latent heating via fusion in polluted conditions are largely canceled by greater condensate loading. Many foundational observational studies supporting invigoration have several fundamental methodological flaws that render their findings incorrect or highly questionable. Thus, much of the evidence for invigoration has come from numerical modeling, but different models and setups have produced a vast range of results. Furthermore, modeled aerosol impacts on deep convection are rarely tested for robustness, and microphysical biases relative to observations persist, rendering many results unreliable for application to the real world. Without clear theoretical, modeling, or observational support, and given that enervation rather than invigoration may occur for some deep convective regimes and environments, it is entirely possible that the overall impact of cold-phase invigoration is negligible. Substantial mesoscale variability of dominant thermodynamic controls on convective updraft strength coupled with substantial updraft and aerosol variability in any given event are poorly quantified by observations and present further challenges to isolating aerosol effects. Observational isolation and quantification of convective invigoration by aerosols is also complicated by limitations of available cloud condensation nuclei and updraft speed proxies, aerosol correlations with meteorological conditions, and cloud impacts on aerosols. Furthermore, many cloud processes, such as entrainment and condensate fallout, modulate updraft strength and aerosol–cloud interactions, varying with cloud life cycle and organization, but these processes remain poorly characterized. Considering these challenges, recommendations for future observational and modeling research related to aerosol invigoration of deep convection are provided.

This paper presents a novel methodology to use direct numerical simulation (DNS) to study the impact of isotropic homogeneous turbulence on the condensational growth of cloud droplets. As shown by previous DNS studies, the impact of turbulence increases with the computational domain size, that is, with the Reynolds number, because larger eddies generate higher and longer-lasting supersaturation fluctuations that affect growth of individual cloud droplets. The traditional DNS can only simulate a limited range of scales because of the excessive computational cost that comes from resolving all scales involved, that is, from large scales at which the turbulent kinetic energy (TKE) is introduced down to the Kolmogorov microscale, and from following every single droplet. The novel approach is referred to as the “scaled-up DNS”. The scaling up is done in two parts, first by increasing both the computational domain and the Kolmogorov microscale and second by using super-droplets instead of real droplets. To ensure proper dissipation of TKE and scalar variance at small scales, molecular transport coefficients are appropriately scaled up with the grid length. For the scaled-up domains, say, meters and tens of meters, one needs to follow billions of real droplets. This is not computationally feasible, and so-called super-droplets are applied in scaled-up DNS simulations. Each super-droplet represents an ensemble of identical real droplets, and the number of real droplets represented by a super-droplet is referred to as the multiplicity attribute. After simple tests showing the validity of the methodology, scaled-up DNS simulations are conducted for five domains, the largest of 643 m3 volume using a DNS of 2563 grid points and various multiplicities. All simulations are carried out with vanishing mean vertical velocity and with no mean supersaturation, similarly to past DNS studies. As expected, the supersaturation fluctuations as well as the spread in droplet size distribution increase with the domain size, with the droplet radius variance increasing in time t as t1∕2 as identified in previous DNS studies. Scaled-up simulations with different multiplicities document numerical convergence of the scaled-up solutions. Finally, we compare the scaled-up DNS results with a simple stochastic model that calculates supersaturation fluctuations based on the vertical velocity fluctuations updated using the Langevin equation. Overall, the results document similar scaling to previous small-domain DNS simulations and support the notion that the stochastic subgrid-scale model is a valuable tool for the multi-scale simulation of droplet spectral evolution applying a large-eddy simulation model.

Abstract Herein we describe the moist dynamics formulation implemented within the graphics processing unit‐resident large‐eddy simulation FastEddy® model, which includes a simple saturation adjustment scheme for condensation and evaporation processes. Two LES model intercomparison exercises for non‐precipitating shallow cumulus clouds are simulated in order to validate this model extension, including a static forcing and a time‐dependent forcing case. Overall, we find our dynamical, thermodynamical and microphysical quantities, along with turbulence variability and fluxes, to be commensurate with the corresponding model intercomparison results. In addition, sensitivities to specific model settings are investigated. Among these settings, it is shown that boundary layer and cloud layer structure and characteristics are sensitive to use of higher‐order advection schemes impacting the vertical distribution of cloud content and associated turbulence statistics. Increasing the timescale of the saturation scheme leads to enhanced liquid water presence and decreases vertical velocity variance within the cloud deck. In some cases, these sensitivities agree with the model‐to‐model variability reported in the intercomparison exercises, highlighting the important role of specific model implementation choices in the context of shallow cumulus convection simulations. These analyses and findings also provide the basis for future extensions and applications of FastEddy® for modeling moist convection and precipitation scenarios.

Thermodynamic soundings for pre-monsoon and monsoon seasons from the Indian subcontinent are analysed to document differences between convective environments. The pre-monsoon environment features more variability for both near-surface moisture and free-tropospheric temperature and moisture profiles. As a result, the level of neutral buoyancy (LNB) and pseudo-adiabatic convective available potential energy (CAPE) vary more for the pre-monsoon environment. Pre-monsoon soundings also feature higher lifting condensation levels (LCLs). LCL heights are shown to depend on the availability of surface moisture, with low LCLs corresponding to high surface humidity, arguably because of the availability of soil moisture. A simple theoretical argument is developed and showed to mimic the observed relationship between LCLs and surface moisture. We argue that the key element is the partitioning of surface energy flux into its sensible and latent components, that is, the surface Bowen ratio, and the way the Bowen ratio affects surface buoyancy flux. We support our argument with observations of changes in the Bowen ratio and LCL height around the monsoon onset, and with idealized simulations of cloud fields driven by surface heat fluxes with different Bowen ratios.

We report the development of a novel Lagrangian microphysics methodology for simulations of warm ice-free clouds. The approach applies the traditional Eulerian method for the momentum and continuous thermodynamic fields such as the temperature and water vapor mixing ratio, and uses Lagrangian super-droplets to represent condensed phase such as cloud droplets and drizzle or rain drops. In other applications of the Lagrangian warm-rain microphysics, the super-droplets outside clouds represent unactivated cloud condensation nuclei (CCN) that become activated upon entering a cloud and can further grow through diffusional and collisional processes. The original methodology allows for the detailed study of not only effects of CCN on cloud microphysics and dynamics, but also CCN processing by a cloud. However, when cloud processing is not of interest, a simpler and computationally more efficient approach can be used with super-droplets forming only when CCN is activated and no super-droplet existing outside a cloud. This is possible by applying the Twomey activation scheme where the local supersaturation dictates the concentration of cloud droplets that need to be present inside a cloudy volume, as typically used in Eulerian bin microphysics schemes. Since a cloud volume is a small fraction of the computational domain volume, the Twomey super-droplets provide significant computational advantage when compared to the original super-droplet methodology. Additional advantage comes from significantly longer time steps that can be used when modeling of CCN deliquescence is avoided. Moreover, other formulation of the droplet activation can be applied in case of low vertical resolution of the host model, for instance, linking the concentration of activated cloud droplets to the local updraft speed. This paper discusses the development and testing of the Twomey super-droplet methodology, focusing on the activation and diffusional growth. Details of the activation implementation, transport of super-droplets in the physical space, and the coupling between super-droplets and the Eulerian temperature and water vapor field are discussed in detail. Some of these are relevant to the original super-droplet methodology as well and to the ice phase modeling using the Lagrangian approach. As a computational example, the scheme is applied to an idealized moist thermal rising in a stratified environment, with the original super-droplet methodology providing a benchmark to which the new scheme is compared.

Abstract A direct numerical simulation (DNS) with the decaying turbulence setup has been carried out to study cloud‐edge mixing and its impact on the droplet size distribution (DSD) applying thermodynamic conditions observed in monsoon convective clouds over Indian subcontinent during the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX). Evaporation at the cloud‐edges initiates mixing at small scale and gradually introduces larger‐scale fluctuations of the temperature, moisture, and vertical velocity due to droplet evaporation. Our focus is on early evolution of simulated fields that show intriguing similarities to the CAIPEEX cloud observations. A strong dilution at the cloud edge, accompanied by significant spatial variations of the droplet concentration, mean radius, and spectral width, are found in both the DNS and in observations. In DNS, fluctuations of the mean radius and spectral width come from the impact of small‐scale turbulence on the motion and evaporation of inertial droplets. These fluctuations decrease with the increase of the volume over which DNS data are averaged, as one might expect. In cloud observations, these fluctuations also come from other processes, such as entrainment/mixing below the observation level, secondary CCN activation, or variations of CCN activation at the cloud base. Despite large differences in the spatial and temporal scales, the mixing diagram often used in entrainment/mixing studies with aircraft data is remarkably similar for both DNS and cloud observations. We argue that the similarity questions applicability of heuristic ideas based on mixing between two air parcels (that the mixing diagram is designed to properly represent) to the evolution of microphysical properties during turbulent mixing between a cloud and its environment.

In this study, we examine the diurnal cycle of rainfall over New Guinea using a series of convection-permitting numerical simulations with the Weather Research and Forecasting (WRF) model. We focus our simulations on a period of suppressed regional-scale conditions (February 2010) during which local diurnal forcings are maximised. Additionally, we focus our study on the occurrence and dynamics of offshore-propagating convective systems that contribute to the observed early-morning rainfall maximum north-east of New Guinea.In general, modelled diurnal precipitation shows good agreement with satellite-observed rainfall, albeit with some timing and intensity differences. The simulations also reproduce the occurrence and variability of overnight convection that propagate offshore as organised squall lines north-east of New Guinea. The occurrence of these offshore systems is largely controlled by background conditions. Days with offshore-propagating convection have more middle tropospheric moisture, larger convective available potential energy, and greater low-level moisture convergence. Convection has similar characteristics over the terrain on days with and without offshore propagation.The offshore-propagating convection manifests via a multi-stage evolutionary process. First, scattered convection over land, which is remnant of the daytime maximum, moves towards the coast and becomes reorganised near the region of coastal convergence associated with the land breeze. The convection then moves offshore in the form of a squall line at ∼ 5 ms−1. In addition, cool anomalies associated with gravity waves generated by precipitating land convection propagate offshore at a dry hydrostatic gravity wave speed (of ∼ 15 ms−1) and act to destabilise the coastal/offshore environment prior to the arrival of the squall line. Although the gravity wave does not appear to initiate the convection or control its propagation, it should contribute to its longevity and maintenance. The results highlight the importance of terrain and coastal effects along with gravity waves in contributing to the diurnal cycle over the Maritime Continent, especially the offshore precipitation maxima adjacent to quasi-linear coastlines.

This paper discusses cloud simulations aiming at quantitative assessment of the effects of cloud turbulence on rain development in shallow ice-free convective clouds. Cloud fields from large-eddy simulations (LES) applying bin microphysics with the collection kernel enhanced by cloud turbulence are compared to those with the standard gravitational collection kernel. Simulations for a range of cloud condensation nuclei (CCN) concentrations are contrasted. Details on how the parameterized turbulent collection kernel is used in LES simulations are presented. Because of the disparity in spatial scales between the bottom-up numerical studies guiding the turbulent kernel development and the top-down LES simulations of cloud dynamics, we address the consequence of the turbulence intermittency in the unresolved range of scales on the mean collection kernel applied in LES. We show that intermittency effects are unlikely to play an important role in the current simulations. Highly-idealized single-cloud simulations are used to illustrate two mechanisms that operate in cloud field simulations. First, the microphysical enhancement leads to earlier formation of drizzle through faster autoconversion of cloud water into drizzle, as suggested by previous studies. Second, more efficient removal of condensed water from cloudy volumes when a turbulent collection kernel is used leads to an increased cloud buoyancy and enables clouds to reach higher levels. This is the dynamical enhancement. Both mechanisms operate in the cloud field simulations. The microphysical enhancement leads to the increased drizzle and rain inside clouds in simulations with high CCN. In low-CCN simulations with significant surface rainfall, dynamical enhancement leads to a larger contribution of deeper clouds to the entire cloud population, and results in a dramatically increased mean surface rain accumulation. These results call for future modeling and observational studies to corroborate the findings.

This paper presents application of the Weather Research and Forecasting (WRF) model to limited-area modeling of atmospheric processes over the subtropical south-eastern Pacific, with the emphasis on the stratocumulus-topped boundary layer. The simulations cover a domain from the VAMOS (Variability of the American Monsoon Systems) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) field project conducted in the subtropical south-eastern Pacific in October and November 2008. We focus on a day where the UK's BAe-146 research aircraft encountered Pockets of Open Cells (POCs) at the very western edge of its flight track, rather than on the entire campaign as investigated in previous limited-area modeling studies. Model results are compared to aircraft observations with the main conclusion that the simulated stratocumulus-topped boundary layer is significantly too shallow. This appears to be a combination of an already too shallow boundary layer in the dataset used to provide initial and lateral boundary conditions, and the inability of the WRF model to increase the boundary-layer height. Several sensitivity simulations, applying different subgrid-scale parameterizations available in the model, a larger computational domain and longer simulations, as well as a different dataset providing initial and lateral boundary conditions were all tried to improve the simulation. These changes appeared to have a rather small effect on the results. The model does simulate the formation of mesoscale cloud-free regions that one might consider similar to Pockets of Open Cells observed in nature. However, formation of these regions does not seem to be related to drizzle-induced transition from open- to closed-cell circulations as simulated by LES models. Instead, the cloud-free regions appear to result from mesoscale variations of the lower-tropspheric vertical velocity. Areas of negative vertical velocity with minima (a few cm s−1) near the boundary layer top seem to induce direct evaporation of the cloud layer. It remains to be seen in LES studies whether the mechanism seen in the model is realistic or if it is simply an artifact of interactions between resolved and parameterized processes.

A large set of rising adiabatic parcel simulations is executed to investigate the combined diffusional and accretional growth of cloud droplets in maritime and continental conditions, and to assess the impact of enhanced droplet collisions due to small-scale cloud turbulence. The microphysical model applies the droplet number density function to represent spectral evolution of cloud and rain/drizzle drops, and various numbers of bins in the numerical implementation, ranging from 40 to 320. Simulations are performed applying two traditional gravitational collection kernels and two kernels representing collisions of cloud droplets in the turbulent environment, with turbulent kinetic energy dissipation rates of 100 and 400 cm2 s−3. The overall result is that the rain initiation time significantly depends on the number of bins used, with earlier initiation of rain when the number of bins is low. This is explained as a combination of the increase of the width of activated droplet spectrum and enhanced numerical spreading of the spectrum during diffusional and collisional growth when the number of model bins is low. Simulations applying around 300 bins seem to produce rain at times which no longer depend on the number of bins, but the activation spectra are unrealistically narrow. These results call for an improved representation of droplet activation in numerical models of the type used in this study. Despite the numerical effects that impact the rain initiation time in different simulations, the turbulent speedup factor, the ratio of the rain initiation time for the turbulent collection kernel and the corresponding time for the gravitational kernel, is approximately independent of aerosol characteristics, parcel vertical velocity, and the number of bins used in the numerical model. The turbulent speedup factor is in the range 0.75–0.85 and 0.60–0.75 for the turbulent kinetic energy dissipation rates of 100 and 400 cm2 s−3, respectively.

Objectives: The Covid-19 pandemic changed daily routines and forced people to develop various coping methods. University students were a social group that suffered due to a drastic change in their daily routine. The analysis of adaptation to chronic stress may help in developing more individualized care for people affected by it., Methods: The examination of coping methods and aggression level was conducted using Brief COPE and STAXI-2 questionnaires on a group of 283 participants, extracted from the initial group of 906 tested students. The study was conducted between the second and the third wave of pandemic in Poland., Results: The positive coping methods were dominant among the examined group. The most used were active coping, use of informational support and planning. The negative coping methods were inextricably linked to a higher aggression level, and were more prevailing in the female students., Conclusions: The first symptoms of maladaptive behaviors may be hidden in presumably usual activities and attitudes. It is important to be aware of them in order to provide support for students and other social groups affected by chronic stress.

Relative consistency is a notion related to entropic parameters, most notably to Approximate Entropy and Sample Entropy. It is a central characteristic assumed for e.g., biomedical and economic time series, since it allows the comparison between different time series at a single value of the threshold parameter r . There is no formal proof for this property, yet it is generally accepted that it is true. Relative consistency in both Approximate Entropy and Sample entropy was first tested with the M I X process. In the seminal paper by Richman and Moorman, it was shown that Approximate Entropy lacked the property for cases in which Sample Entropy did not. In the present paper, we show that relative consistency is not preserved for M I X processes if enough noise is added, yet it is preserved for another process for which we define a sum of a sinusoidal and a stochastic element, no matter how much noise is present. The analysis presented in this paper is only possible because of the existence of the very fast NCM algorithm for calculating correlation sums and thus also Sample Entropy.

Objectives: Neurosurgical audits are an important part of improving the safety, efficiency and quality of care but require considerable resources, time, and funding. To that end, the advent of the Artificial Intelligence-based algorithms offered a novel, more economically viable solution. The aim of the study was to evaluate whether the algorithm can indeed outperform humans in that task., Patients & Methods: Forty-six human students were invited to inspect the clinical notes of 45 medical outliers on a neurosurgical ward. The aim of the task was to produce a report containing a quantitative analysis of the scale of the problem (e.g. time to discharge) and a qualitative list of suggestions on how to improve the patient flow, quality of care, and healthcare costs. The Artificial Intelligence-based Frideswide algorithm (FwA) was used to analyse the same dataset., Results: The FwA produced 44 recommendations whilst human students reported an average of 3.89. The mean time to deliver the final report was 5.80 s for the FwA and 10.21 days for humans. The mean relative error for factual inaccuracy for humans was 14.75 % for total waiting times and 81.06 % for times between investigations. The report produced by the FwA was entirely factually correct. 13 out of 46 students submitted an unfinished audit, 3 out of 46 made an overdue submission. Thematic analysis revealed numerous internal contradictions of the recommendations given by human students., Conclusion: The AI-based algorithm can produce significantly more recommendations in shorter time. The audits conducted by the AI are more factually accurate (0 % error rate) and logically consistent (no thematic contradictions). This study shows that the algorithm can produce reliable neurosurgical audits for a fraction of the resources required to conduct it by human means., Competing Interests: Declaration of Competing Interest The authors report no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Introduction: Arterial hypertension is among the most important risk factors of atherosclerosis and associated cardiovascular pathology with a prevalence rate estimated at 20-30% of the adult population. Nowadays, it is recommended to perform an individual assessment of cardiovascular risk in a patient and to determine the threshold value for arterial hypertension, even though blood pressure classification values according to the European Society of Hypertension and the European Society of Cardiology (ESH/ESC), as well as the Polish Society of Hypertension (PTNT) have remained unchanged., Aim of Study: To determine what nurses with a Bachelor of Nursing degree know about the prevalence and classification of arterial blood pressure, as well as sequellae of arterial hypertension., Materials and Methods: This study was done in 116 qualified nurses (112 females, 4 males; age 21-50; seniority 0-29 years). The research period was from June 2007 to January 2008. The research tool was a questionnaire devised by the authors., Results: We found that half (on the average) of those questioned have an up-to-date knowledge regarding classification of blood pressure and prevalence of arterial hypertension but just one out of three respondents (on the average) was able to describe its sequellae. Relatively less known among nurses with a Bachelor of Nursing degree were aspects of "white coat hypertension". Statistically significant differences regarding correct answers were noted depending on seniority (p = 0.002), place of work p < 0.001), or position (p < 0.001). There were no differences depending on age, place of residence, marital status, or form of postgraduate education of nurses with a Bachelor of Nursing degree., Conclusion: It is necessary to improve knowledge among students of nursing (BN degree) about current classification of blood pressure, as well as prevalence of arterial hypertension and its sequellae.

Introduction: Alcohol abuse is one of the main causes of arterial hypertension. Alcohol is responsible for a few to more than ten percent of all cases of primary hypertension, particularly in persons consuming more than 20-30 g of alcohol per day. The aim of this study was to find out what Bachelor of Nursing degree holders know about alcohol consumption styles and the effects of alcohol on blood pressure, as well as on the risk of arterial hypertension in adults., Material and Methods: The study group comprised 116 qualified nurses (112 females, 4 males; age 21-50 years; work seniority 0-29 years). The study was done between June 2007 and January 2008 with the use of the diagnostic poll technique based on a questionnaire developed by the authors., Results: We found that 8.62% of participants were informed about screening tools used for evaluating styles of alcohol consumption while 41.38% gave the correct definition of the standard portion of alcohol. The alcohol consumption threshold above which the risk of hypertension becomes significant was known to 58.62% of respondents. The influence of alcohol (drunk directly before blood pressure measurement) on blood pressure was known to 89.66% of the nurses. We observed a statistically significant effect of work experience (p = 0.002), place of work (p < 0.001), and position held (p < 0.001) on the number of correct answers. No statistically significant differences depending on age, place of residence, family status or type of postgraduate education were noted., Conclusion: It is necessary to increase awareness among nurses regarding the risk of arterial hypertension associated with alcohol consumption and to improve the effectiveness of undergraduate and postgraduate education aimed at early recognition of problems caused by alcohol consumption which are important for the prevention of arterial hypertension.

1. When cardiac preparations are rewarmed following prolonged hypothermia a transient hyperpolarization occurs in K-containing media. This hyperpolarization is correlated with the active Na efflux. It might be due to electrogenic Na pumping or to extracellular K depletion brought about by the activity of an electroneutral Na-K exchange pump. In order to distinguish between these mechanisms the effect of various extracellular K concentrations ([K](o)) on the membrane potential of guineapig atria was studied before and after hypothermia.2. The membrane potential increased with decreasing [K](o) before cooling. It reached values of -64 and -92 mV at 10.8 and 0 mM-K, respectively.3. The membrane hyperpolarized transiently after hypothermia beyong the potential observed before cooling. Maximal values of about -94 mV were obtained during rewarming in solutions containing 0.4-2.7 mM-K. The membrane potential was significantly lower (-88 mV) in K-free media. It was also diminished at [K](o) higher than 2.7 mM and was measured to be -74 mV at 10.8 mM-K.4. The hyperpolarization of the cell membrane during the first 20 min of rewarming was maximal at 2.7 mM-K and yielded 15.5 mV. The hyperpolarization amounted to 7.2 and 10 mV at 0.4 and 10.8 mM-K, respectively. No hyperpolarization occurred in K-free solutions.5. The rate of decline of the transient hyperpolarization increased with [K](o).6. Variations of membrane input resistance after changes in [K](o) were measured in rewarmed atrial trabecula. The measurements revealed an increase in membrane resistance in lower [K](o).7. It is concluded that the transient hyperpolarization of the cardiac cell membrane during rewarming is due to the activation of an electrogenic Na pump.8. The (relative) strength of the pump current at various [K](o) was derived from the observed dependence of the hyperpolarization and of the membrane input resistance on [K](o). The current is estimated to be half-maximal at about 1.5 mM-K.

1 In spontaneously active Purkinje fibres of young cows the dose-response curves of the action of isoprenaline upon different electrophysiological parameters were measured.2 The increase in slope of diastolic depolarization could roughly be described by a one-for-one binding curve with a half maximum effect near 10(-8) M and the increase in the height of the plateau level by a two-for-one binding curve with a half maximum effect near 10(-7) M (-)-isoprenaline.3 These dose-response curves were similar to those of two parameters measured under voltage clamp conditions by other authors. The increase in slope of diastolic depolarization behaved like the shift of the activation curve for the pacemaker potassium current towards positive potentials and the growth in plateau height like the increase in the slow inward current mainly carried by Ca ions. From this conformity we propose that the parameters evaluated by us from action potential records could be used for a qualitative analysis of the action of catecholamines on pacemaker potassium current and Ca influx.4 The effects of the isomers of a new drug, 1-isopropylamino-3(4'hydroxyphenoxy)-propan-2-ol (IHP), were evaluated in the same way as those of isoprenaline. The (-)-isomer was at optimal concentrations (10(-5) M) nearly half as effective as isoprenaline in increasing frequency and slope of diastolic depolarization but caused no increase in plateau height. An identical relationship, but at 5 to 10 times higher concentrations, was obtained with the (+)-isomer.5 When 10(-4) M(-)-IHP was added to a preparation equilibrated with a maximum dose of (-)-isoprenaline (10(-6) M), frequency and plateau height declined. This result together with the observation that the effects of IHP could be blocked by the specific beta-antagonist propranolol, revealed the beta-agonistic nature of the new drug. Its inefficiency in increasing the plateau height and thus the slow (Ca) inward current was explained by its relatively low potency and intrinsic activity.

Twenty-five radiographic studies representative of the spectrum of trauma cases that might present to an emergency department were selected from actual cases presenting at Brooke Army Medical Center (BAMC) in San Antonio, Texas. The studies were then transmitted from a local television studio via satellite back to BAMC and three other Army hospitals. A panel of 29 physicians (11 radiologists, 7 emergency physicians, and 11 others from various specialty areas) viewed the images on commercial grade television sets and attempted to make a diagnosis. The diagnostic accuracy of the radiologists (86%) was significantly better than that of the other two groups (77% each). However, given the overall expense of a teleradiology network, this difference in accuracy - especially when translated into clinically significant errors - might not justify the establishment of such a network in terms of cost-effectiveness.