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There are two allochthonous salt canopies within the central Scotian margin, one on the shelf and another in deeper waters on the Scotian slope. The Sable Shelf Canopy trends southwest-northeast and covers an area approximately 650 [km.sup.2]. Salt thickness within this canopy is generally Deux domes de sel allochtone se trouvent dans la bordure Scotian centrale, un sur la plateforme et l'autre dans les eaux plus profondes de la pente Scotian. Le dome de plateforme Sable a une tendance sud-ouest-nord-est et couvre une region d'environ 650 [km.sup.2]. L'epaisseur du sel dans ce dome est generalement inferieure a 1000 m. La recharge du sel a erode les bordures de ce dome, reduisant grandement son etendue. La tectonique du sel associee a ce dome a produit plusieurs des cibles d'exploration forees sur la plateforme. Le dome de pente Sable est cinquante kilometres vers l'interieur du bassin sur la pente Scotian. Ce dome est beaucoup plus grand, couvrant 12 700 [km.sup.2] et le sel allochtone atteint des epaisseurs de 3500 m. Bien que les deux domes soient separes par une distance importante, une surface commune de decollement les relie a plusieurs endroits. Des systemes d'extension se detachent dans le dome de plateforme Sable, deplacent les strates vers l'aval-pendage et expulsent le sable vers le dome de pente Sable. La plateforme externe et la region de la pente separant ces deux domes sont dominees par des systemes de decollement. Le terme Complexe du dome Sable a ete developpe pour decrire a la fois les deux domes de sel et la zone de decollement qui les separe. L'interpretation des donnees sismiques 2D et 3D a travers tout le Complexe du dome Sable a produit une carte detaillee du sel allochtone et de tous les elements connexes, incluant les systemes soudes, les diapirs de sel, les sutures et les mini-bassins. Quatre styles distincts d'expulsion contribuent du sel aux domes : les decollements dans le sel, les systemes contreregionaux, les hybrides et les diapirs de sel. Des explications possibles pour les variations dans les styles d'expulsion seraient les volumes variables d'apport de sediments, les positions paleogeographiques a la bordure et la longueur de la nappe de sel. [Traduit par la Redaction], Introduction Salt-sediment interactions on the Scotian margin have previously been documented by various authors: Wade and MacLean (1990), Kidston et al. (2002), Shimeld (2004), Ings and Shimeld (2006), Albertz and [...]

The parabolic surface profiles of the Hormuz and Namakdan salt diapirs in the Persian Gulf suggest that they have been extruding with Newtonian viscous rheologies for the last [10.sup.4] years. We derive velocity profiles for these diapirs, neglecting gravitational spreading and erosion/dissolution while assuming incompressible Newtonian rheology of the salt. Fitting known rates of extrusion at specific points in its elliptical cross-section, the dynamic viscosity of the salt of the Hormuz diapir is found to range between [10.sup.18] and [10.sup.21] Pa s. Approximating its sub-circular cross-section to a perfect circle, the range of viscosity of the salt of the Namakdan diapir is obtained as [10.sup.17]-[10.sup.21] Pa s. These calculated viscosities fall within the range for naturally flowing salts elsewhere and for other salt diapirs but are broader than those for salts with Newtonian rheology deforming at room temperatures. The salts of the Hormuz and Namakdan diapirs are expected to exhibit a broader range of grain size, which matches the limited existing data. Keywords: Hormuz diapir, Namakdan diapir, salt diapir, viscosity, Newtonian viscous fluid. doi: 10.1017/S001675680999077X

The majority (~70%) of surface buried in protein folding is hydrocarbon, whereas in DNA helix formation, the majority (~65%) of surface buried is relatively polar nitrogen and oxygen. Our previous quantification of salt exclusion from hydrocarbon (C) accessible surface area (ASA) and accumulation at amide nitrogen (N) and oxygen (O) ASA leads to a prediction of very different Hofmeister effects on processes that bury mostly polar (N, O) surface compared to the range of effects commonly observed for processes that bury mainly nonpolar (C) surface, e.g., micelle formation and protein folding. Here we quantify the effects of salts on folding of the monomeric DNA binding domain (DBD) of lac repressor (lac DBD) and on formation of an oligomeric DNA duplex, in accord with this prediction, no salt investigated has a stabilizing Hofmeister effect on DNA helix formation. Our ASA-based analyses of model compound data and estimates of the surface area buried in protein folding and DNA helix formation allow us to predict Hofmeister effects on these processes. We observe semiquantitative to quantitative agreement between these predictions and the experimental values, obtained from a novel separation of coulombic and Hofmeister effects. Possible explanations of deviations, including salt-dependent unfolded ensembles and interactions with other types of surface, are discussed. Hofmeister salts | m-values | thermodynamics doi: 10.1073/pnas.0913376107

The so-called 'simple salt approximation' is used to calculate the lattice energies of double salts (compounds that contain two or more different types of ions). Enthalpies and Gibbs energies of dissolution based upon these lattice energies are then used to estimate the solubilities of hydroxyl sulfates, hydroxyl carbonates, hydroxyl nitrates, hydroxyl chlorides, and hydroxyl phosphates. Based on the solubilities, general rules are postulated for the relative stabilities of double salts that have the same cations and anions, but in different stoichiometries. These observations provide an understanding of the relative stabilities of many minerals and guidance for the design of synthetic methods, and have been used to prepare likasite [[Cu.sub.3]N[O.sub.3][(OH).sub.5] x [2H.sub.2]O], the zinc analog [[Zn.sub.3]S[O.sub.4][(OH).sub.4]] of antlerite [[Cu.sub.3]S[O.sub.4][(OH).sub.4]], and [Cu.sub.5][(S[O.sub.4]).sub.2][(OH).sub.6] x 4[H.sub.2].). Keywords: Thermodynamics, solubility, stoichiometry, lattice energy DOI: 10.2138/am.2010.3244

A photogeologic and physical modeling study indicates that Hebes Chasma, Mars, formed by collapse of the megaregolith. Local heating facilitated drainage of ~10s km3 of brines and entrained particulates through fractures in the chasma floor and into a regional aquifer. A megaregolith rich in salts and water is implied by massive, low-gradient allochthonous flows that terminate in deep pits and troughs, by emergent diapirs, and by arching of Hebes Mensa. These structures are consistent with plastic and viscous deformation but inconsistent with collapse of basalt flows and/or tephra. Spectral measurements confirm that hydrated sulfate salts are spatially associated with allochthonous flows from depth and light-toned deposits. Collapse features and flows are present in many other chasmata in Valles Marineris, suggesting that widespread salt tectonics and dissolution may have shaped the region.

Artifacts in two-dimensional electrophoresis (2-DE) caused by the presence of salts in isoelectric focusing (IEF) have been previously described as a result of increasing conductivity and inducing electroosmosis. However, electrolysis induced by the presence of salts should not be disregarded. In this study, electrolytic reduction-oxidation reaction (redox) was found to be enhanced in the presence of salts in IEF. The consequence of the electrolytic redox leads to acidification of the low-pH region and alkalization of the high-pH region within the immobilized pH gradient (IPG) strip. As a result, a breakdown of immobilized pH buffer near the high pH region of IPG strips along with reduction of basic proteins resulted in uncharacterized artifacts in 2-DE. Electrolytic reduction in the presence of alkali and alkaline metal ions was demonstrated to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), protein disulfide bonds, and protein carboxylic acids. Importantly, semipreparative electrolytic reduction of proteins can be carried out in the presence of sodium ions in a homemade electrolytic apparatus. These findings give additional explanations to the observed artifacts in 2-DE and reveal the unknown effects of salts in IEF. Moreover, we have provided a method with the potential to convert proteins or peptides to corresponding modified products containing aldehyde groups that can be used for conjugation with amine-containing compounds.

In secondary ion mass spectrometry, the molecular environment from which a sample is analyzed can influence ion formation, affecting the resulting data. With the recent surge in studies involving examination of biological specimens, a better understanding of constituents commonly found in biological matrixes is necessary. In this article we discuss results from an investigation directed at understanding the role of salts doped as alkali chlorides in a model biological environment, arginine. The data show that addition of salt to the model system causes ion suppression of all the major mass spectral peaks attributed to arginine, with KCl having the largest suppression effect. Potential causes for the suppression effects are briefly discussed in relation to collected data. These theories include sample degradation, formation of salt adduct peaks, and anion neutralization. Investigation of the arginine salt data in comparison with data collected from pure salt systems indicates that suppression of the positive secondary ions is likely caused by a neutralization process involving the salt counteranion, chloride. To address the suppression issue, various procedures were performed on the arginine films such as sample washing with a cleaning solution (ammonium formate, ethanol, water) and analysis of films in a frozen-hydrated state. We present data from the analysis of the frozen-hydrated samples that shows both an ion yield enhancement and a significant amelioration of the salt suppression effects when compared to the samples run under standard conditions, demonstrating that it is a helpful approach to dealing with salt suppression.

Salts that accumulate near the soil surface with subsurface drip irrigation (SDI) can hinder the establishment of succeeding direct-seeded crops. To prevent crop loss or yield reduction, producers rely on sprinklers for germination, which is often expensive and requires added capital inputs. Predicting salt movement and accumulation with SDI will allow producers to anticipate the need for sprinkler irrigation for salt control. The HYDRUS-2D model was used to model salt accumulation from an SDI system on successive crops of cantaloupe (Cucumis melo L. ssp. melo var. cantalupensis Naudin) and broccoli (Brassica oleracea L. var. italica Plenck) with two tape depths (18 and 25 cm), different germination practices (germination with SDI and with sprinklers), and water salinity (1.5 and 2.6 dS [m.sup.-1]). Predicted saturated-paste electrical conductivity (ECe) values from HYDRUS-2D were significantly correlated with actual ECe data obtained from field experiments ([r.sup.2] = 0.08-0.93). After Season 1, the correlation coefficients were highly variable, with the majority of model ECe values being higher than field data. Season 2 results indicated a much stronger relationship, with [R.sup.2] values as high as 0.93. Model predictions for Season 2 showed underprediction of ECe when compared with actual ECe. Relationships between model-predicted ECe and actual ECe resulted in a slope of nearly 1.0 for all treatments and a y intercept close to -1 dS [m.sup.-1]. A better understanding of the processes that occur at the field scale, such as root growth, root distribution, and plant water uptake, is essential for modeling water and solute transport with SDI. A better characterization of evapotranspiration from SDI is required to accurately model salt accumulation. Abbreviations: ECe, electrical conductivity of saturated paste extract; ECw, electrical conductivity of water; ET, evapotranspiration; Kc, crop evapotranspiration coefficient; SDI, subsurface drip irrigation.

The crystal chemistry of six crystals of general formula [K.sub.2] [[M.sup.2+][([H.sub.2]O).sub.6]][(S[O.sub.4).sub.2], with [M.sup.2+] = Mg, Fe, Co, Ni, Cu, and Zn, was investigated by single-crystal structure analysis to determine the effects of the chemical variation of [M.sup.2+] on the structural environment surrounding K, M, and S sites. Results indicate that the distortion in the S[O.sub.4] tetrahedron and the M[O.sub.6] octahedron is very small, except for Cu[O.sub.6] where it is pronounced because of the Jahn-Teller effect. The K[O.sub.8]-octacoordinate polyhedron has the highest degree of distortion, and its idealized shape may be referred to as a bicapped trigonal prism. The S[O.sub.4] size is not affected by changes in cation occupancies at the adjacent M site. In contrast, changes in the K[O.sub.8] size, which are accompanied by changes in the bond valence sum at K, depend on interaction with the first and second coordination sphere of M. This interaction results by changes in M-O individual lengths, by expansion of the second coordination sphere of M, and by changes in the distribution of the bond strengths over the O atoms coordinated to K. The M[O.sub.6] size follows the expected trend from the increased ionic radius at the M site. The latter is also correlated with the unit-cell volume except for the Cu- and Mg-phase, which show a larger cell volume with respect to that expected. Although the relevant octahedral distortion around the [Cu.sup.2+] cation explains the volume excess in the Cu-phase, an expansion of the second coordination sphere of [Mg.sup.2+], compared to those of cations of larger ionic radius (such as Zn and Co), explains the excess of the unit-cell volume in the Mg-phase. As the Cu[O.sub.6] distortion can be caused by the Jahn-Teller effect, the higher ionicity of the Mg atom could be the cause for its anomalous behavior observed in Tutton's salts. This stereochemical behavior of the Mg atom seems to be consistent with the weakening of the hydrogen bonds in the structure connected to differences in the bonding character of Mg and transition metals when coordinated by water molecules. Keywords: Crystal synthesis, Tutton's salts, crystal structure, bond valence

Anion analysis is of great importance to many scientific areas of interest. Problems with negative mode ESI-MS prevent researchers from achieving sensitive detection for anions. Recently, we have shown that cationic reagents can be paired with anions, such that detection can be done in the positive mode, allowing for low limits of detections for anions using ESI-MS. In this analysis, we present the use of 16 newly synthesized flexible linear tricationic ion-paring reagents for the detection of 11 divalent anions. These reagents greatly differ in structure from previously reported trigonal tricationic ion-pairing agents, such that they are far more flexible. Here we present the structural features of these linear trications that make for good ion-pairing agents as well as show the advantage of using these more flexible ion-pairing reagents. In fact, the limit of detection for sulfate using the best linear trication was found to be 25 times lower than when the best rigid trication was used. Also, MS/MS experiments were performed on the trication--dianion complex to significantly reduce the detection limit for many dianions. Limits of detection in this analysis were as low as 50 fg.

Salt is abundant in biological samples and can cause problems in capillary electrophoresis (CE) due to excessive Joule heating and electrodispersion. Desalting with solid phase minibeds is currently most compatible with the small sample volumes of CE. They are however difficult to prepare and suffer from poor bed-to-bed reproducibility. Alternatively, enrichment of proteins and peptides was developed using CE, by trapping them at their isoelectric points with a discontinuous buffer of mismatched pH. Ionic salts, such as sodium chloride, do not possess isoelectric points and therefore are not retained by the discontinuous buffer. In this work, the removal of ionic salt during protein enrichment using CE with discontinuous buffers was investigated. Nonbuffering ions were found to electromigrate through the pH junction without disrupting the enrichment process and were eventually removed from the capillary. Mass spectral data obtained from the enriched and desalted sample confirmed a significant signal enhancement. Finally, a strong acid was introduced to remove the pH junction and thus facilitated a subsequent capillary zone electrophoresis separation. An integrated procedure of enrichment, desalting, and separation was demonstrated on a mixture of three protein standards.

Excessive salt can reduce soybean yield [Glycine max (L.) Merr.] in grower fields. Salt-tolerant cultivars are needed to prevent field yield losses where excess salt is a problem. Soybean genotypes have primarily been evaluated for reaction to salt in the greenhouse using a labor-intensive and costly hydroponics method. A reliable, inexpensive method to screen soybean lines for salt tolerance would be useful in breeding programs. A simple, inexpensive method of exposing V2 to V3 plants growing in a sandy soil in plastic cone-tainers (PC method) was compared to the hydroponics method to evaluate soybean genotypes for salt tolerance in the greenhouse. Fourteen soybean genotypes including checks 'Hutcheson' (sensitive), and 'S-100' and 'Forrest' (tolerant)were exposed to 100 mM salt solution at the V2 to V3 growth stage. Genotypes responded similarly to the screening methods except leaf scorch, an indicator of salt damage, appeared up to 4 d sooner in the PC method. The PC method was highly correlated with the hydroponics method for leaf scorch score and chloride content in soybean leaves among the 14 genotypes evaluated. Exposure of roots at the V2 to V3 growth stage to salt solution using the PC method was less labor intensive, consumed less time, was less costly, and gave similar results compared with the hydroponics method. Thus, the PC method is an easy, reliable method to screen soybean genotypes for salt tolerance.

Salinity has been recognized as a constraint for soybean [Glycine max (L.) Merr.] production in many regions worldwide. Fortunately, genetic variation in salt tolerance is available in the soybean germplasm bank. However, current screening methodologies for salt-tolerant genotypes are time-consuming and often ineffective because of their limitations in detecting and measuring plant response to salinity. The objective of this study was to develop a rapid visual method for screening soybean genotypes in response to salt stress based on foliar symptoms. Soybean seedlings were grown in hydroponics with 0, 40, 80, 120, or 160 mM NaCl. Visual foliar symptoms of excessive NaCl were evident at 26 d after planting (14 d in 120 and 160 mM NaCl treatment). The NaCl level of 120 mM was most effective for salt-tolerance screening based on visual foliar symptoms on a group of differential genotypes. Chloride includers ('Williams', 'Clark', 'HBK R4924', and 'Dare') exhibited interveinal chlorosis, while CI excluders ('S-100', 'Lee 68', and 'HBK R5525') showed no chlorosis at the 120 mM NaCl level. At this critical selection level (120 mM NaCl), average leaf Na and [Cl.sup.-] contents were 2.64 and 1.96 times higher, respectively, for Cl includers than for Cl excluders. Plant damage was more evident at 120 and 160 mM NaCl, as demonstrated by the decreased shoot and root biomass and near maximum accumulation of Na and [Cl.sup.-] in the tissue. There was a significant and negative correlation (r = -0.69, p = 0.0006) between relative root dry weight and [Cl.sup.-] concentration in the leaf. This methodology is simple, rapid, and effective for selection of Cl tolerant genotypes with a minimum investment of cost and time.

Of all the technologies being developed for solar thermal power generation, central receiver systems (CRSs) are able to work at the highest temperatures and to achieve higher efficiencies in electricity production. The combination of this concept and the choice of molten salts as the heat transfer fluid, in both the receiver and heat storage, enables solar collection to be decoupled from electricity generation better than water/steam systems, yielding high capacity factors with solar-only or low hybridization ratios. These advantages, along with the benefits of Spanish legislation on solar energy, moved SENER to promote the 17 [MW.sub.e] Solar TRES plant. It will be the first commercial CRS plant with molten-salt storage and will help consolidate this technology for future higher-capacity plants. This paper describes the basic concept developed in this demonstration project, reviewing the experience accumulated in the previous Solar TWO project, and present design innovations, as a consequence of the development work performed by SENER and CIEMAT and of the technical conditions imposed by Spanish legislation on solar thermal power generation. [DOI: 10.1115/1.2807210] Keywords: solar power plant, CRS, central tower, molten salt, tube receiver, solar TRES

Molten salt technology represents nowadays the most cost-effective technology for electricity generation for stand-alone solar power plants. Although this technology can be applied to both concentrating technologies, parabolic through and central receiver systems (CRSs), CRS technology can take advantages from its higher concentration, allowing to work at higher temperatures and therefore with a reduction in the size and cost of the storage system. The receiver system is the 'door' for which the energy passes from the field collector to the thermal-electric cycle; it represents, therefore, the core of the CRS and its performance directly affects plant production. Starting from the published lessons from SOLAR TWO receiver technology, the validation of an improved receiver for molten salt technology was assumed as part of the SOLAR TRES solar thermal power commercial plant development. Main challenges for the new receiver were to increase its allowable peak flux up to 1 MW/[m.sup.2] in order to maximize the thermal efficiency of the CRS solar power plant, and to improve its safe life without limiting the incident fluxes that the field of heliostats is able to deliver with an optimized pointing strategy. Several advanced features in geometric and thermodynamic aspects and in its material selection have been implemented on the receiver. With the results of a sensitivity analysis carried out with an own code developed by SENER (SENREC), a prototype receiver panel was designed, fabricated, and installed in a proper test bed at the PSA. Test validation on this panel was carried out in 2007. The initial test results show a very good behavior of the prototype receiver, which allows to anticipate that the objectives of its design can be fulfilled. SENER and CIEMAT have joined forces to face up the challenge of sizing and designing a new molten salt receiver of high thermal efficiency, able to operate at high fluxes without compromising its durability (at least 25 years). Main challenges for the new receiver design were to optimize the receiver dimensions and receiver tube sizes and material selection to surpass the operating conditions in the new plants with respect to SOLAR TWO. [DOI: 10.1115/1.2884576] Keywords: central receiver, high flux, solar power plant, new generation

Protein N-glycosylation in the endoplasmic reticulum (ER) and in the Golgi apparatus is an essential process in eukaryotic cells. Although the N-glycosylation pathway in the ER has been shown to regulate protein quality control, salt tolerance, and cellulose biosynthesis in plants, no biological roles have been linked functionally to N-glycan modifications that occur in the Golgi apparatus. Herein, we provide evidence that mutants defective in Nglycan maturation, such as complex glycan 1 (cgl1), are more salt-sensitive than wild type. Salt stress caused growth inhibition, aberrant root-tip morphology, and callose accumulation in cgl1, which were also observed in an ER oligosaccharyltransferase mutant, staurosporin and temperature sensitive 3a (stt3a). Unlike stt3a, cgl1 did not cause constitutive activation of the unfolded protein response. Instead, aberrant modification of the plasma membrane glycoprotein KORRIGAN 1/RADIALLY SWOLLEN 2 (KOR1/RSW2) that is necessary for cellulose biosynthesis occurred in cgl1 and stt3a. Genetic analyses identified specific interactions among rsw2, stt3a, and cgl1 mutations, indicating that the function of KOR1/RSW2 protein depends on complex N-glycans. Furthermore, cellulose deficient rswl-1 and rsw2-1 plants were also salt-sensitive. These results establish that plant protein Nglycosylation functions beyond protein folding in the ER and is necessary for sufficient cell-wall formation under salt stress. complex N-glycans | endoplasmic reticulum stress | salt stress

The simple salt approximation for the lattice energy of double salts is used to provide an estimate of their molar solubilities. These calculations are compared with solubilities obtained from literature thermodynamic data and are within an order of magnitude for about 75% of the 81 minerals and other double salts examined. The solubilities of about two-thirds of the double salts are similar to the solubilities of the less soluble simple salt 'constituents,' and the solubilities of the other one-third lie between the solubilities of the 'constituents.' In general, the solubilities of a series of salts with different stoichiometries containing the same ions are dependent on both the stoichiometry of the salt and the proportion of the less soluble constituent. This generalization is rationalized with the simple salt approximation and is used to explain the observed stoichiometries of a variety of minerals. Keywords: Thermodynamics, solubility, stoichiometry, lattice energy

Human beings have been continuously exposed to natural radioactive rays since their existence in the world. From the end of the 19th century, besides natural sources, mankind has been exposed inevitably to artificial radioactive sources with the development of technology. Radiation has beneficial effects on human beings but also can have harmful consequences if overexposed. Therefore, it is important for both public and governmental institutions to know radioactivity levels, particularly in foodstuffs, for human health. There have been rumours among the public that the level of radioactivity in salt minerals exported from abroad is high. In this study, the radioactivity levels of imported and domestic salts on the market shelves have been determined by using gamma spectrometry units with HPGe detector. Key words: salt, natural radioactivity, HPGe detector, committed effective dose. Depuis toujours, les humains ont ete exposes a la radioactivite naturelle. A partir de la fin du 19e siecle, des sources artificielles sont venues s'ajouter au bilan suite au developpement de la technologie. La radiation peut etre benefique a l'humain, mais peut aussi etre nocive, surtout en cas de surdose. Par consequent, il est important pour les institutions publiques et gouvernementales de connaitre le niveau de radioactivite, particulierement dans la nourriture destinee aux humains. Il y a des rumeurs dans le public que le niveau de radioactivite dans des sels mineraux importes est eleve. Dans cette etude, nous utilisons la spectrometrie gamma utilisant un detecteur HPGe pour determiner le niveau de radioactivite de sels domestiques et importes trouves sur les tablettes. [Traduit par la Redaction] Mots-cles: sel, radioactivite naturelle, detecteur HPGe, dose efficace engagee, concentration d'activite., 1. Introduction Humans have been continuously irradiated by gamma rays from the natural radioactive substances found in the Earth and from cosmic rays. According to the UNSCEAR Report [1], the [...]

A method that enables students to visualize the differences in solubility between salts is discussed. The effect of acid-base equilibria on solubility is demonstrated through the use of copper compounds.

A novel synthetic method is developed for a salt of 2-{[2-(3,4-dichlorophenyl)-ethyl]propylamino}-1-pyridin-3-ylethanol and the dynamic and conformational properties of its salt form are characterized. The results have shown a diastereomeric effect in the salt form of a racemic tertiary arylalkylamine and some NMR spectroscopic evidence are provided to demonstrate the mechanisms underlying this effect.

The synthesis, structure, and physical properties of BIS(ethylenedithio)tetrathiafulvalene Ni(1,2,5-thiadiazole-3,4-dihiolate)2 [(BEDT-TTF)[Ni(tdas)2], which is the first example of a salt containing monomeric [Ni(tdas)2](super -) monoanions, are reported. It can be concluded that the unpaired electron lies on the [Ni(tdas)2](super -) anions.

Impurities in water are behind the ripples seen around an icicle's circumference. Ripples or ribs form naturally in icicles, an effect that previous theories attributed to surface tension in the [...]