Head size

Stadler C and Sohmid F 1999 Phase behavior of grafted ohain moleoules influenoe of head size and ohain length J. Chem. Phys. 110 9697... 

Simulations of monolayers have focused on internal phase transitions, e.g., between the expanded phase and the condensed phases, between different tilted phases, etc. These phenomena cannot be reproduced by models with purely repulsive interactions. Therefore, Haas et al. [148,149] represent the amphiphiles as stiff Lennard-Jones chains, with one end (the head bead) confined to move in a plane. In later versions of the model [150-152], the head bead interactions differ from those of the tail beads they are taken to be purely repulsive, and the head size is variable. 

Stadler et al. [150,151] have performed Monte Carlo simulations of this model at constant pressure and calculated the phase behavior for various different head sizes. It turns out to be amazingly rich. The phase diagram for chain length N = 1 and heads of size 1.2cr (cr being the diameter of the tail beads) is shown in Fig. 8. A disordered expanded phase is found as well as... 

The modulated phase disappears for head sizes smaller than 1.14c7. Modulations of this kind have not been observed in experiments so far. 

Both the stability and curvature of the emulsions are dependent on the head sizes as is indicated from the following figures for the stability and mean diameter of benzene-water emulsions emulsified with various metallic oleates. 

Note The presence of fatty acids may be determined as follows Add oo a 250ml beaker about 200ml of water and place a pin-head size grain of camphor on the surface. (The beaker should be perfectly clean (greaseless) and should not be touched on the inside with the fingers). If the water is free of grease, -the camphor will start to move m a rotary manner. Add a few ml of the glycerol o be tested and observe the behavior of the camphor. If it stops and remains motionless, it indicates the presence of fatty acids. Mineral oils are without effect... 

Fig. 5 Britain and Ireland aerosol overview (location shown in the inset), (a) Histograms of N10o concentration in both stations, (b) Mace Head size distributions, showing 16th, median (thick line), and 83rd percentiles of size distribution functions...

Vavrova, K., et al. 2003. L-serine and glycine based ceramide analogues as transdermal permeation enhancers Polar head size and hydrogen bonding. Bioorg Med Chem Lett 14 2351. 

Proportion. Included in proportion is the visual agreement of relative parts, such as a head size compared to a body size or furniture size compared to room size, and also agreeable relationships of intangible features such as the intensity of a blue color as compared to yellow in a sunset painting. In addition, it is often stated that odd... 

Microbore systems are intended for use with column diameters ranging up to 2 mm. The narrow column diameter and small size of the packing material decree relatively low flow rates for the pumping system, from 1 to 250 /il/min. As the minimum head size for reciprocating pumps is around 25 /A, smooth, reliable operation at flow rates less than 10 jul/min is difficult. 

During the 3 months following their birth, both sisters sustained recurrent upper respiratory illnesses. These were more severe in Elizabeth, who required frequent hospitalizations. Physical examination of both infants during this period disclosed poor feeding habits, failure to thrive, floppiness, microcephaly (small head size), and delayed developmental milestones. They were below the fifth percentile for weight and height. These findings were more pro-... 

Hack, M., Breslau, N., Weissman, B., Aram, D., Klein, N., Borawski, E. (1991). Effect of very low birth weight and subnormal head size on cognitive abilities at school age. N. Engl. J. Med. 325 231-7. 

Dessens AB, Cohen-Kettenis PT, Mellenbergh GJ, Koppe JG, van De Poll NE, Boer K. Association of prenatal phenobarbital and phenytoin exposure with small head size at birth and with learning problems. Acta Paediatr 2000 89(5) 533-41. 

Head size as a correlated proxy for brain size (0.65). 

Humphrey I want to come back to the question of correlation and causation. It s tempting of course to assume that a relation between two variables is causal when we can see how it would work, but to assume it s a mere correlation when we can t see it. So, when we find that IQ correlates with brain size or head size, we think that s probably because large brains do indeed cause high IQ. But when we find IQ... 

Detterman Related to that, has anyone ever looked at head size as being a factor in attractiveness ... 

Gangestad It seems that smaller heads on males might be more attractive. Body size and head size do not scale isomorphically, so it might be that smaller heads represent larger body size. Statues tend to have smaller heads. 

---