Fast and Slow Components in the Crystallization of a Model Multicomponent System, NaKCa(NO₃): The Role of Composition Fluctuations

We use calorimetrically detected crystal nucleation and growth studies to broaden the discussion of fluctuation-induced nucleation processes to include composition fluctuations in ionic complex-forming systems. We use the model system Ca(NO3)2–KNO3 with NaNO3 introduced as a third component, so that crystallization kinetics can be controlled by change of alkali cation at constant mole fraction of Ca(NO3)2. At fixed NaNO3 content, we find separate and thermodynamically anomalous kinetics for the crystallization of NaNO3 and Ca(NO3)2,which we attribute to the importance of slow concentration fluctuations in the latter case. The “nose” of the time–temperature–transformation TTT curve for crystallization of the Ca(NO3)2 occurs at much higher temperatures and longer times than that for NaNO3 and the shape of the curve is different. Above the metastable liquidus surface of NaNO3, supercooled ternary melts can persist for long times. Suppression of the fast NaNO3 crystallization, by replacement of Na+ by K+, is a prerequisite for easy vitrification in this system

Open-field Y-shape trail-following bioassays with workers of <i>O. formosanus</i> at different nutrition levels.

<p>The sample arrangements were (3<i>Z</i>)-dodec-3-en-1-ol (DOE) in one branch and (3<i>Z</i>,6<i>Z</i>)-dodeca-3,6-dien-1-ol (DDE) in the base and in the other branch at the same concentration. Worker from I to III, the former was less fed than the latter. The same protocol was used as in footnote of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090906#pone-0090906-t003" target="_blank">Table 3</a>. Arm selection was calculated in ≥Base workers (that follow trails longer than the base branch). Significance of DDE arm selection was the statistical comparison between the total number of workers selected DDE arm and the number of workers going further than the base.</p

Dynamics of the walking speed, distance and number of workers in the searching and food-collecting process in <i>O. formosanus.</i>

<p>The error bar in each column indicates the standard deviation. (A) Typical performance of the four phases in the foraging process, using buckwheat powder (Bkw) as food. I phase with workers searching in fixed directions (arrows); G phase with the recruitment of workers after the food was discovered; S phase with workers going back and forth between the nest and the food under the protection of the mud shelters (MS); D phase with fewer workers collecting food under the mud shelters. (B) Speed dynamics of the searching workers in the first 30 min of each searching cycle. Number of searching termites tracked in the video file was 170 from 9 experiments. The walking speed of workers while searching forward (Fw) away from the nest increased linearly (<i>R²</i> = 0.61), and the speed of the workers returning to the nest (Bw) increases linearly (<i>R²</i> = 0.63). (C) Speed dynamics of the workers throughout the foraging process. <i>N</i> = 20 for each column; those columns marked with different small letters are significantly different (<i>P <</i>0.001). (D)Time-based increase of the trail length walked by each pioneer termite in the arena. In the analyzed 4 experiments (Exp 1 to 4), the trail lengths was extended by pioneer termites in exponential trends (From Exp 1 to 4, numbers of traced pioneer termites were 13, 8, 10, and 20, <i>R²</i> = 0.90, 0.97, 0.90, and 0.90, respectively). (E) The number of termites in the foraging arena in the I phase before the food was found (sampled every 5 min, from 10 experiments). If not disturbed, the number of searching termites in the arena increased logistically (<i>N</i> = 48, <i>R²</i> = 0.91) with an upper bound of 280. (F) Dynamics of the worker population before the mud shelters were built throughout the searching and food-collecting process in the presence of three types of food: Bkw, corncob (Cncb), or bark of the locust tree <i>Robinia pseudoacacia</i> (Blt). After the number of termites had increased logistically in the I phase, termites were recruited intensively with more worker encountered the food in G, S and D phase of foraging. The chaotic running was judged by the ratio of number of termites away from/on a trail. When the ratio was up to 30%, chaotic running was defined, and the phenomenon of chaotic running synchronized with surge of termite in S phase.</p

GC analysis of <i>O. formosanus</i> worker and soldier sternal gland extracts.

<p>(A) Comparative analysis of a 50 sternal gland extract (top) and the tergal surface (bottom) of 50 D phase workers on an HP-5 column, showing that peaks A and B are glandular specific. (B) Comparative analysis of a 15 searching worker gland extract and a 15 soldier gland extract on a DB-WAX column, showing that only compound B was present in soldiers, whereas both compounds A and B were present in workers. (C) Co-injection of <i>n</i>-alkanes to calculate the linear retention indices (LRIs) on an HP-5 column. The chromatogram was generated from an extract from a total of 60 trailing workers. LRIs of A and B were 1449 and 1457, respectively.</p

GC-MS analysis of a 135 <i>O. formosanus</i> worker sternal glands extract on a DB-WAX column.

<p>(A) Co-injection of <i>n</i>-alkanes to calculate the linear retention indices (LRIs) on a DB-WAX column. LRIs of A and B were 1996 and 2047, respectively. (B) Mass spectra of peaks A and B separated corresponded to those of (3<i>Z</i>)-dodec-3-en-1-ol and (3<i>Z</i>,6<i>Z</i>)-dodeca-3,6-dien-1-ol, respectively. Other peaks were contaminants from air or cuticular hydrocarbons according to their mass spectra.</p

Open-field Y-shape trail-following bioassays with <i>O. formosanus</i> activated D phase workers showing preference to recruitment pheromone.

<p>The sample arrangements were 0.01 gnawing worker sternal gland extract (0.01 GWG/cm) laid in base and one arm, (3<i>Z</i>)-dodec-3-en-1-ol (DOE), (3<i>Z</i>,6<i>Z</i>)-dodeca-3,6-dien-1-ol (DDE), soldier sternal gland extract (SDG), and searching worker sternal gland extract (SWG) laid down in the other arm for contrast. The same protocol was used as in footnote of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090906#pone-0090906-t003" target="_blank">Table 3</a>.</p

Quantification of the trail pheromone in the foraging trail of <i>O. formosanus</i> with trail-following bioassays in choice test with sternal gland extracts (SG) and (3<i>Z</i>)-dodec-3-en-1-ol (DOE).

<p>Quantification of the trail pheromone in the foraging trail of <i>O. formosanus</i> with trail-following bioassays in choice test with sternal gland extracts (SG) and (3<i>Z</i>)-dodec-3-en-1-ol (DOE).</p

Component ratios of the trail pheromone in workers of <i>O. formosanus</i> under various behavior contexts.

<p>DDE indicates (3<i>Z</i>,6<i>Z</i>)-dodeca-3,6-dien-1-ol; DOE indicates (3<i>Z</i>)-dodec-3-en-1-ol. Numbers of workers used in each extraction are indicated by <i>N</i>; numbers of replicates are indicated by <i>M</i>. Columns marked with same letters are not significantly different (<i>LSD</i> multiple comparison, <i>P</i>>0.05). Asterisk indicates data obtained from freshly collected nests. Number that follows the ± sign is a standard devia­tion.</p

Y-shape trail-following bioassays using activated workers for active thresholds and synergistic effect.

<p>Samples were (3<i>Z</i>)-dodec-3-en-1-ol (DOE), (3<i>Z</i>,6<i>Z</i>)-dodeca-3,6-dien-1-ol (DDE), a blend of both compounds, a sternal gland extract (GEQ), an abdominal tergites extract (WEQ) in <i>O. formosanus</i> workers or soldiers. Hexane was used as control in the other branch. Selections were analyzed with a Mann-Whitney U-test with Continuity Correction (***<i>P</i><0.001; **<i>P<</i>0.01; ns, not significant, <i>P</i> > 0.05). The columns marked with the same small letter were not significantly different (<i>Diff</i>) (<i>P</i> > 0.05); <i>n</i> indicated the total number of termites used.</p

Open-field Y-shape trail-following bioassays with (3<i>Z</i>,6<i>Z</i>)-dodeca-3,6-dien-1-ol exposed <i>O. formosanus</i> workers.

<p>(3<i>Z</i>)-Dodec-3-en-1-ol (DOE) or (3<i>Z</i>,6<i>Z</i>)-dodeca-3,6-dien-1-ol (DDE) can be applied in the base and/or in one of the branches at the same concentration. The same protocol was used as in footnote of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090906#pone-0090906-t003" target="_blank">Table 3</a>. ≥ DDE base indicated the number of termites following a trail longer than the base and making a choice between the two branches. Significance of DDE base was the statistical comparison between the number of workers going further than the base and the total number of workers tested. Significance of arm was the statistical comparison between the number of termites choosing one or the other branch.</p