On the linear growth rates of the long-wave modes in Bénard–Marangoni convection

1997 ◽  
Vol 9 (8) ◽  
pp. 2455-2457 ◽  
Author(s):  
S. K. Wilson ◽  
A. Thess
1955 ◽  
Vol 33 (5) ◽  
pp. 416-428 ◽  
Author(s):  
D. E. Etheridge

Cultures of Fames annosus originating in Europe could not be distinguished from those originating in North America either by colony appearance, growth rate, pH optimum, or cellulolytic activity. Three growth rate types on 2.5% malt agar were recognized and these are ascribed to individual variation rather than to host or geographical influences. Successive subculturing produced variants that fell into three growth classes. Half of the isolates displayed spontaneous, but reversible, changes in growth rate and colony appearance during subculturing and this is discussed from the standpoint of genetical and environmental influences. Cultures displaying different morphological characteristics and linear-growth rates differed little metabolically; each had a similar pH optimum ranging from 4.6 to 5.5, and each proved capable of altering the initial acidity of the medium to a reaction which was more suitable for growth. Two cultures were characterized by double pH optima at 4.6 and 5.5. Cultures having different linear-growth rates produced about the same dry-weight of mycelium on a cellulose substrate in a semisynthetic nutrient solution. On the basis of a statistical analysis of cellulose utilization by representative isolates it was impossible to distinguish between North American and European cultures.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Sydney Olson ◽  
Marniker Wijesinha ◽  
Annalise Panthofer ◽  
William Blackwelder ◽  
Gilbert R Upchurch ◽  
...  

Objective: Small abdominal aortic aneurysms (AAAs) have a low risk of rupture. Intervention is indicated when diameters exceed established thresholds. This study assessed the growth rates and patterns of AAAs over 2 years as documented on serial CT scans from the Non-Invasive Treatment of AAA Clinical Trial. Methods: 254 patients, 35 females with baseline AAA maximum transverse diameter (MTD) between 3.5-4.5 cm and 219 males with baseline MTD 3.5-5.0 cm, were included in this study. Linear regressions and segmental growth rates were used to model growth rates and patterns. Results: The yearly growth rates of AAA MTDs had a median of 0.17 cm/yr and mean of 0.19 cm/yr ± 0.14 (Figure 1). 10% of AAA displayed minimal to no growth (< 0.05 cm/yr), 62% low growth (0.05-0.25 cm/yr), 28% high growth (> 0.25 cm/yr). Baseline AAA diameter accounted for only 5.4% of growth rate variance (P<0.001, R 2 0.05). Most AAAs displayed linear growth (70%); large variations in interval growth rates occurred infrequently (3% staccato growth, 4% exponential growth); a minority of subjects’ growth patterns were not clearly classifiable (11% indeterminate-not growing, 12% indeterminate-growing) (Figure 2). No patients with baseline MTD < 4.25 cm exceeded sex-specific repair thresholds (males 0 / 92, [95% CI, 0.00-0.06]; females 0 / 25 [95% CI, 0.00-0.25]) in the course of follow-up for as long as two years. Conclusions: The majority of small AAAs exhibit linear growth; large intra-patient growth rate variations were infrequently observed over 2 years. AAA < 4.25 cm can be followed with a CT scan in 2 years with little chance of exceeding interventional MTD thresholds of 5.5 cm for men.


1988 ◽  
Vol 192 ◽  
pp. 287-312 ◽  
Author(s):  
N. F. Smyth

The effect of dissipation on the flow of a stratified fluid over topography is considered in the weakly nonlinear, long-wave limit for the case when the flow is near resonance, i.e. the basic flow speed is close to a linear long-wave speed for one of the long-wave modes. The two types of dissipation considered are the dissipation due to viscosity acting in boundary layers and/or interfaces and the dissipation due to viscosity acting in the fluid as a whole. The effect of changing bottom topography on the flow produced by a force moving at a resonant velocity is also considered. In this case, the resonant condition is that the force velocity is close to a linear long-wave velocity for one of the long-wave modes. It is found that in most cases, these extra effects result in the formation of a steady state, in contrast to the flow without these effects, which remains unsteady for all time. The flow resulting under the action of boundary-layer dissipation is compared with recent experimental results.


2020 ◽  
Vol 2 (1) ◽  
pp. 15
Author(s):  
Matteo Postacchini ◽  
Lorenzo Melito ◽  
Alex Sheremet ◽  
Joseph Calantoni ◽  
Giovanna Darvini ◽  
...  

We illustrate recent findings on the upriver propagation of long waves entering the mouth of the Misa River (Senigallia, Italy). Such a microtidal environment has been recently studied to understand river–sea interactions: it has been found that the river forcing dominates over the marine actions in winter, especially during storms. However, upriver wave propagation is not negligible with low-frequency waves propagating upriver for distances of the order of kilometers. With the aim to better understand the behavior of low-frequency waves propagating upriver, the analysis of the present work builds on field data collected by instruments installed close to the mouth and along the final reach of the Misa River: a tide gauge, two hydrometers and an acoustic Doppler sensor. It has been here observed that the tidal forcing (periods of the order of hours/days) is significantly strong at a distance of more than one kilometer from the river mouth, while shorter waves, like seiches (periods of some hours), are less important and are supposed to largely dissipate at the estuary, although their role could be of importance during relatively short events (e.g., floods).


1997 ◽  
Vol 29 (1) ◽  
pp. 91-96 ◽  
Author(s):  
M. Webster ◽  
D. H. Brown

AbstractPeltigera canina thalli have been successfully transplanted onto soil in a garden and in flowerpots. Garden samples showed marked seasonality and achieved growth rates of 6·4 cm per year. Pot-grown samples showed variation in the growth of individual thallus lobes and established that, under different soil hydration regimes, permanently hydrated thalli could sustain considerable linear growth rates for at least 140 days.


1981 ◽  
Vol 34 (9) ◽  
pp. 1845 ◽  
Author(s):  
LH Cohen ◽  
Jr W Klement

Differential thermal analyses have located the transitions between low-temperature I and high-temperature II phases in AgNO3 powder and single crystals under hydrostatic pressures </~0.7 GPa, with heating/cooling rates in the range 0.1-1.5 K s-1. Isobaric transition temperatures plot linearly against heating/cooling rates and, extrapolated to zero rate, show hystereses between I → II and II → I transition temperatures which are comparable with the 'regions of indifference' of Bridgman's isothermal experiments. The present results suggest an initial slope of -0.090 μK Pa-1 and zero initial curvature for the I-II phase boundary. Greater hystereses are observed for the I-II transitions near intersection with the II-II' λ transition at </~0.7 GPa. An improved, quantitative description is achieved for the Kennedy-Schultz data on the linear growth rates of II,II? → I at 0.1 MPa. For II' (with ordered NO3- ions) → I the growth rates show temperature dependence markedly different than growth rates for II(with disordered NO3-) → 1 and I → II.


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