Convergent evolution?
The more Dr. Lewis watched firefly courtship, the clearer it became that the females were carefully choosing mates. They start dialogues with up to 10 males in a single evening and can keep several conversations going at once. But a female mates with only one male, typically the one she has responded to the most.
Carl Zimmer, “Blink Twice if You Like Me”, New York TImes, 30 June 2009, p. D1.
Men and women are rotated to meet each other over a series of short “dates”, usually lasting from 3 to 8 minutes depending on the organization running the event. At the end of each interval, the organizer rings a bell or clinks a glass to signal the participants to move on to the next date. At the end of the event participants submit to the organizers a list of who they would like to provide their contact information to.
“Speed Dating”, Wikipedia, 25 June 2009.
On the occasion of arriving in Paris for the summer, a special edition of Journal Paper of the Day.
G. Vázquez, F. Chenlo, R. Moreira, A. Costoyas, “The Dehydration of Garlic. I. Desorption Isotherms and Modelling of Drying Kinetics” and “The Dehydration of Garlic. II. The Effects of Pretreatments on Drying Kinetics”, in Drying Technology, Vol. 17, No. 6, 1999, pp. 1095–1108 and pp. 1109–1120.
Key words and phrases: drying of sliced garlic (Allium sativum. L.); desorption isotherms; diffusional kinetic model; variation in volume; rehydration ratio; blanching; solutions of potassium carbonate; potassium carbonate and olive oil; sodium hydroxide or sodium metabisulfile.
Key quotes:
“There is very little published work on the drying of garlic” (p. 1096).
“Fresh heads of garlic (Allium sativum. L.) were purchased from a local market” (ibid).
Key equation:
The solution obtained for diffusion within a planar slab under the assumption that moisture transfer is unidirectional, that the initial moisture is uniformly distributed in the substrate, that external resistance to heat and mass transfer is negligible, and that the volume of the substrate and the effective diffusion coefficient of moisture in it are constant throughout the drying process:
![\displaystyle X^{*} = \dfrac{X-X_e}{X_0-X_e} = \dfrac{8}{\pi^2} \sum^{\infty}_{n=0} \dfrac{1}{(2n+1)^2} e^{\Biggl[\displaystyle -(2n+1)^2 \dfrac{\pi^2D_{\text{eff}}t}{L^2}\Biggr]}](http://s.wordpress.com/latex.php?latex=%5Cdisplaystyle%20X%5E%7B%2A%7D%20%3D%20%5Cdfrac%7BX-X_e%7D%7BX_0-X_e%7D%20%3D%20%5Cdfrac%7B8%7D%7B%5Cpi%5E2%7D%20%5Csum%5E%7B%5Cinfty%7D_%7Bn%3D0%7D%20%5Cdfrac%7B1%7D%7B%282n%2B1%29%5E2%7D%20e%5E%7B%5CBiggl%5B%5Cdisplaystyle%20-%282n%2B1%29%5E2%20%5Cdfrac%7B%5Cpi%5E2D_%7B%5Ctext%7Beff%7D%7Dt%7D%7BL%5E2%7D%5CBiggr%5D%7D&bg=ffffff&fg=000000&s=0 "\displaystyle X^{*} = \dfrac{X-X_e}{X_0-X_e} = \dfrac{8}{\pi^2} \sum^{\infty}_{n=0} \dfrac{1}{(2n+1)^2} e^{\Biggl[\displaystyle -(2n+1)^2 \dfrac{\pi^2D_{\text{eff}}t}{L^2}\Biggr]}")
Where X* is the dimensionless moisture content, Xt, X0 and Xe are the moisture contents in kg of water per kg dry mass at time t (in s), at t = 0 (initial value) and at equilibrium, respectively; Deff the effective diffusion coefficient (in m2s-1); and L is the half-thickness of the slab (in m). Planar slab geometry is justified by geometrical considerations and by structural properties of garlic because the slices were obtained with the natural external wall (less permeable to water) as the cylindrical wall allowing, practically, to remove the water though both planar faces.
In the same issue of the journal can be found a technical note on the drying of chopped spring onion.
