Calmodulin resolution of multiple peaks of activity by preparative electrofocusing

Despite the popularity of the horizontal to vertical spectral ratio (HVSR) method in site effect studies, the origin of the H/V peaks has been controversial since this method was proposed. Many previous studies mainly focused on the explanation of the first or single peak of the H/V ratio, trying to distinguish between the two hypotheses &#8212; the S-wave resonance and ellipticity of Rayleigh wave. However, it is common both in numerical simulations and practical experiments that the H/V ratio exhibits multiple peaks, which is essential to explore the origin of the H/V peaks.The cause for the multiple H/V peaks has not been clearly figured out, and once was simply explained as the result of multi subsurface layers. Therefore, we adopted numerical method to simulate the ambient noise in various layered half-space models and calculated the H/V ratio curves for further comparisons. The peak frequencies of the H/V curves accord well with the theoretical frequencies of S-wave resonance in two-layer models, whose frequencies only depend on the S wave velocity and the thickness of the subsurface layer. The same is true for models with varying model parameters. Besides, the theoretical formula of the S-wave resonance in multiple-layer models is proposed and then supported by numerical investigations as in the cases of two-layer models. We also extended the S-wave resonance to P-wave resonance and found that its theoretical frequencies fit well with the V/H peaks, which could be an evidence to support the S-wave resonance theory from a new perspective. By contrast, there are obvious differences between the higher orders of the H/V ratio peaks and the higher orders of Rayleigh wave ellipticity curves both in two-layer and multiple-layer models. The Rayleigh wave ellipticity curves are found to be sensitive to the Poisson&#8217;s ratio and the thickness of the subsurface layer, so the variation of the P wave velocity can affect the peak frequencies of the Rayleigh wave ellipticity curves while the H/V peaks show slight change. The Rayleigh wave ellipticity theory is thus proved to be inappropriate for the explanation of the multiple H/V peaks, while the possible effects of the Rayleigh wave on the fundamental H/V peak still cannot be excluded.Based on the analyses above, we proposed a new evidence to support the claim that the peak frequencies of the H/V ratio curve, except the fundamental peaks, are caused by S-wave resonance. The relationship between the P-wave resonance and the V/H peaks may also find further application.

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Multiple peaks in human nerve action potentials

Electroencephalography and Clinical Neurophysiology ◽

10.1016/0013-4694(87)92216-4 ◽

1987 ◽

Vol 66 (5) ◽

pp. S112

Keyword(s):

Action Potentials ◽

Multiple Peaks ◽

Nerve Action ◽

Human Nerve

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The Behaviour and Ecology of Austrolittorina antipodum and Austrolittorina cincta: Models for Marine Reserve Connectivity Studies

10.26686/wgtn.16997680.v1 ◽

2021 ◽

Author(s):

◽

Jennifer Vander Veur

Keyword(s):

Gene Flow ◽

Larval Mortality ◽

Marine Reserve ◽

Sex Ratios ◽

Marine Conservation ◽

Population Connectivity ◽

Adult Density ◽

Population Surveys ◽

Multiple Peaks ◽

High Shore

Determining the magnitude of dispersal and connectivity between populations has important implications for marine conservation. Species with limited dispersal capabilities exhibit restricted gene flow leading to isolation and, ultimately, differentiated populations. In this ecological study I investigated the gastropods Austrolittorina antipodum (Philippi, 1847) and Austrolittorina cincta (Quoy and Gaimard, 1833) to determine how ecology and behaviour influence the dispersal and connectivity of these species. The aim of this study was to determine population size and structure, settlement, fecundity, and adult movement rates. Methodologies included: population surveys, deployment of settlement pads and adult density manipulations, dissections, and a tagging study. These elements of a species ecology and behaviour can enhance or restrict population connectivity by: cohort partitioning resulting from habitat requirements, fluctuating settlement due to variable larval mortality or adult densities impacting dispersal, skewed sex ratios and effective populations sizes altering larval production, and adult movement leading to behavioural isolation or facilitating gene flow, along with other possible effects. Population surveys revealed both species had a Vermeij (1972) "type 1 distribution" (shell size increasing from the low to high shore), with the highest density of individuals on the low shore and the majority of mature adults on the high shore. Overall, A. antipodum was 16 times more abundant than A. cincta. Shifts to a smaller mean size of both species, along all shore heights following periods of peak settlement indicates settlers are potentially triggering competitive interactions or ontogenetic migrations in other cohorts.Settlement surveys revealed that peak settlement for Austrolittorina spp. was from February to April, declining at the beginning of March. Multiple peaks in settlement may act as a buffer limiting the potential of stochastic events to hinder dispersal during reproductive seasons. Settlement rates were not affected by adult density in control treatments; however, settlement was higher on pads deployed within adult populations compared to pads deployed adjacent to adult populations, suggesting the presences of adults has some effect on settlement. Fecundity results revealed A. antipodum to have more mature females than A. cincta, with males of both species reaching sexual maturity before females. Sex ratios of both species were skewed towards more females, with effective population sizes that included approximately 88% of each species population. A. antipodum’s larger population may be due to variation between the species' demographics, such as the distribution of mature females and juveniles leading to greater spawning success and juvenile survivorship. Tagging transplant/translocation experiments used to examine movement revealed that both species traveled similar distances. On average A. antipodum traveled 24.1m (±23.5m) and A. cincta traveled 18.7m (±16m) in eight months. There was no evidence of behavioural isolation occurring between low and high shore individuals. The wide ranging movements of adults indicated adults have the potential to maintain population connectivity on small scales. The findings of this study suggest both species facilitate dispersal with multiple peaks in settlement, large effective populations, and high adult mobility. Behavioural variation between the species appears to affect population connectivity, with the distribution of A. antipodum demographics potentially enhancing connectivity.

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Microheterogeneity of adenosine cyclic monophosphate-dependent protein kinases from mouse brain and heart

Biochemical Journal ◽

10.1042/bj1750367 ◽

1978 ◽

Vol 175 (2) ◽

pp. 367-375 ◽

Cited By ~ 11

Author(s):

A M Malkinson ◽

A J Gharrett ◽

L Hogy

Keyword(s):

Protein Kinase ◽

Cyclic Amp ◽

Mouse Brain ◽

Deae Cellulose ◽

Type I ◽

Type Ii ◽

Catalytic Subunits ◽

Multiple Peaks ◽

Dependent Protein ◽

Brain Cytosol

1. DEAE-cellulose chromatography of mouse brain cytosol indicated the presence of only the type II isoenzyme of cyclic AMP-dependent protein kinase. Mouse heart cytosol contained approximately equal amounts of the type I and type II isoenzymes. 2. Both brain and heart type II isoenzymes reassociated after a transient exposure to cyclic AMP, but the heart type I isoenzyme remained dissociated. 3. Elution of brain cytosol continuously exposed to cyclic AMP resolved multiple peaks of protein kinase and cyclic AMP-binding activities. A single peak of kinase and multiple peaks of cyclic AMP-binding activities were found under the same conditions with heart cytosol. Various control experiments suggested that the heterogeneity within the brain type II isoenzymic class had not been caused by proteolysis. 4. Kinetic experiments with unfractionated brain cytosol showed that the binding of cyclic AMP, the dissociation of cyclic AMP from protein and the rate of heat denaturation of the cyclic AMP-binding activity gave results consistent with the presence of multiple binding species. 5. It concluded that the type II isoenzymic peak obtained by DEAE-cellulose chromatography of mouse brain cytosol represents a class of enzymes containing multiple regulatory and catalytic subunits. The two heart cytosol isoenzymes contain a common catalytic subunit. The degree of protein kinase ‘microheterogeneity”, defined as the presence of multiple regulatory and/or catalytic subunits within a single isoenzymic class, appears to be tissue-specific.

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