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Diaspore banks are crucial for the maintenance and resilience of plant communities, but diaspore banks of bryophytes remain poorly known, especially from tropical ecosystems. This is the first study to focus on the role of diaspore banks of bryophytes in tropical rain forests. Our aim was to test whether microhabitat (substrate type) and species traits (breeding system, phylum) are important in explaining the diaspore bank composition. Using samples cultivated in the laboratory, we assessed the number of species and shoots emerging from bark, decaying wood and soil from two sites of the Atlantic rain forest (montane and sea level) in Brazil by comparing the contribution of species by phylum (mosses, liverworts) and breeding system (monoicous, dioicous). More species emerged from bark (68) and decaying wood (55) than from soil (22). Similar numbers of species were found at both sites. Mosses were more numerous in terms of number of species and shoots, and monoicous species dominated over dioicous species. Substrate pH had only weak effects on shoot emergence. Species commonly producing sporophytes and gemmae had a high contribution to the diaspore banks. These superficial diaspore banks represented the extant vegetation rather well, but held more monoicous species (probably short-lived species) compared to dioicous ones. We propose that diaspore bank dynamics are driven by species traits and microhabitat characteristics, and that short-term diaspore banks of bryophytes in tropical rain forests contribute to fast (re)establishment of species after disturbances and during succession, particularly dioicous mosses investing in asexual reproduction and monoicous mosses investing in sexual reproduction. [ABSTRACT FROM AUTHOR]

The factors responsible for the patterns of niche differentiation and narrow endemism have rarely been investigated in annual Mediterranean plants. This topic was addressed here by performing comparative studies on realized niches, regional occupancy, global biogeographical distribution and seed traits of a set of Arenaria (Caryophyllaceae) species inhabiting southern Provence (SE France), focusing in particular on Arenaria provincialis, a narrow endemic restricted to the hills and modest calcareous mountains around the city of Marseille. Field studies were carried out from 2008 to 2009 at 624 sites in the limestone mountains where Arenaria species are likely to occur. The Arenaria species occurring in southern Provence vary greatly in their patterns of regional occupancy and their biogeographical distribution. Multivariate analysis of the realized niche showed that they have some similar limiting environmental factors in common, but they do not all occupy the same habitats. Studies on the fruits and seeds showed that the endemic A. provincialis has a larger seed than its congeners and a capsule that remains closed and falls from the plant at maturity. This well-differentiated diaspore specific to A. provincialis may be responsible for the limited dispersal capacity of this species. Phylogenetic analyses showed that A. provincialis is not closely related to the other taxa inhabiting southern Provence, but rather to Arenaria occurring in highland areas in the south of France. The restricted pattern of distribution of A. provincialis is probably due to the past isolation event from which it originated and to its limited dispersal capacity, rather than resulting from its ecological niche range. [ABSTRACT FROM AUTHOR]

Abstract: The existed collector for the flotation of diasporic bauxite in China is poor in selectivity. To look for a collector with high selectivity and strong collecting capacity on the diaspore flotation, novel 4-alkyl-4,4-bis(hydroxycarbamoyl) carboxylic acids (ABHC) including 4,4-bis(hydroxycarbamoyl) dodecanoic acid (HCDA), 4,4-bis(hydroxycarbamoyl) tetradecanoic acid (HCTA), and 4,4-bis(hydroxycarbamoyl) hexadecanoic acid (HCHA) were designed and synthesized for the beneficiation of diasporic bauxite by selective flotation. The results of flotation experiments for the single minerals showed that by using these compounds as collectors, the pulp pH value has significant influence on their collecting performance as the floatability of diaspore varies sharply with its change. The appropriate pH value for the flotation of diaspore gets close to neutral condition at which diaspore presents good floatability while kaolinite and illite exhibit poor floatabilities. HCDA, HCTA, and HCHA, especially HCDA, show good selectivity for the flotation between diaspore and aluminosilicate around pH 7. A satisfactory mass ratio of Al2O3 to SiO2 (A/S) and recovery of Al2O3 were obtained from the flotation separation of artificially mixed minerals and the flotation desilication of diasporic bauxite by using HCDA as a collector, proving that the selectivity of HCDA is better than that of the traditional collector oleate. Moreover, adsorption amount, zeta-potential, DFT calculation, XPS, and FTIR were performed to study the mechanisms. The results indicated that the adsorption of HCDA on the surface of diaspore is dominantly chemisorption in the form of three chelate rings. The oxygen atoms contained in carboxyl and hydroxycarbamoyl of the polar group have the highly negative charges and stereo conditions to form five- to eight-membered ring, resulting in the coordination of carboxyl and hydroxycarbamoyl to the metal aluminum atoms to form chelate rings. By contrast, the adsorption of HCDA on the surface of kaolinite or illite is mainly physical adsorption. [Copyright &y& Elsevier]

We have measured the pressure-induced change in the lattice dynamics of diaspore, α-AlO(OH), by in situ Raman spectroscopy up to 25 GPa. The spectra are evaluated by density functional perturbation theory-based atomistic model calculations. The assignment of calculated to experimentally observed Raman bands is based on the calculation of Raman intensities. We discuss the accuracy of the approach employed for these calculations and explain the relative magnitudes of mode Grüneisen parameters. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Novel compounds of hydroxycarbamoyl carboxylic acids, including 2-hydroxycarbamoyl -3-methlcyclohexane carboxylic acid (HCMC), 2-hydroxycarbamoylmethyl decylen-4-yl carboxylic acid (HCDC) and 2-hydroxycarbamoylmethyl tridecylen-4-yl carboxylic acid (HCTC) were synthesized. The flotation behaviors of diaspore, kaolinite and illite using these compounds as collectors were investigated. The flotation results revealed that the floatability of the minerals was, in descending order, diaspore and kaolinite, followed by illite, and the ability to collect the minerals was, in ascending order, HCMC and HCDC, followed by HCTC. At a dosage of 2×10-4 mol/L, both HCDC and HCTC show a strong ability to collect diaspore and a weak ability to float kaolinite and illite. The flotation recovery of diaspore is over 90% and that of kaolinite and illite less than 30%. Moreover, Fourier transform infrared spectroscopy (FTIR) spectrum and zeta potential, as well as the adsorption amount, indicated that the adsorption interaction between HCTC and diaspore was primarily a kind of chemisorption in the form of chelate rings, while the interaction between the collector and aluminosilicate mineral was dominated by physisorption. It was concluded that the novel hydroxycarbamoyl carboxylic acid compounds are highly selective collectors for the flotation of diaspore vs. aluminosilicate minerals. [ABSTRACT FROM AUTHOR]

Abstract: The flotation behaviors of kaolinite and diaspore were investigated using N,N-dipropyl dodecyl amine (PN). Maximum recoveries of kaolinite and diaspore were about 90% and 50%, respectively. Both recoveries of kaolinite and diaspore increased with the increasing dosage of PN. On the basis of the zeta potential and FT-IR spectra, the ionization of surface hydroxyl and the isomorphic exchange of surface ions account for the charging mechanisms of surfaces of kaolinite and diaspore. The adsorption mechanism of PN on the surface of two minerals was mainly electrostatic. After reacting with PN, the zeta potential of kaolinite and diaspore both increased, and comparing with the original zeta potentials, potential of kaolinite increased much more than that of diaspore, this can explain why recovery of kaolinite is higher than that of diaspore. [Copyright &y& Elsevier]

The article reports on the recovery of diaspore crystals near Pinarcik, Turkey. It mentions that the best crystals and groups of crystals share all the characteristics that have made the cut stones interesting. It indicates that mining and recovery have emphasized production of gem rough, not mineral specimens. It encourages production of mineral specimens from the deposit.

Abstract: The Paleogene aged metabauxite deposit in the Upper Cretaceous-Early Paleogene aged marble sequence within the southwestern Menderes Massif in the İlbir Mountains of the Milas (Muğla) region of SW Turkey comprises many initially karst unconformity-type bauxite horizons with unusual Al-mobility. Thus, it displays singular geochemical and mineralogical implications. The settling down of these horizons was syngenetic with limestone sedimentation, as evidenced by their lithologic associations. In the region, they are mainly found as karst unconformity diasporite-type upper bauxite horizons due to lower-graded burial metamorphism in the Küçükçamlık and Büyükçamlık hills, and also found as emery type lower bauxite horizons due to higher-graded burial metamorphism in the Meneviş and Kure streams. The main focus of this study was the upper bauxite horizons because they contain significant secondary Al- and Fe(Ti)-rich mineralization in the structurally-controlled open spaces (fracture zones) crosscutting the brittle bauxite horizons. This secondary mineralization is unique worldwide because the fracture zones contain coarse crystals of secondary minerals, such as gem-quality diaspore, muscovite, specular hematite, ilmenite, goethite, and chloritoid. These secondary metamorphic minerals were formed by high-temperature hydrothermal activity involving metamorphic remobilized reactions of extraction, mobilization, migration and re-crystallization, from the primary metamorphic mineral constituents in the metabauxite ore bodies. Thus, within the well known Mediterranean Bauxite Belt (MBB) in southern Europe trending from Portugal through Turkey, the metabauxite deposit in the İlbir Mountains is noteworthy for the coexistence of two serial phases of metamorphic mineralization which occurred when the metabauxite deposit was modified by late-stage Alpine tectono-metamorphism in the Menderes Massif. This study is mainly focused on the original primary metamorphic submicroscopic mineralization, including polycrystalline (overlapped) occurrences, and uses the comparative matching technique on X-ray diffraction patterns to confirm that the main constituents of the karst unconformity-type diasporic metabauxite (diasporite) ore were the main source for secondary metamorphic mineralization in the fracture zones. It was found that the submicroscopic mineral constituents in the original primary diasporite ore are diaspore, gibbsite, corundum, specular hematite, ilmenite, donbassite and chloritoid as major constituents, with goethite, ferroalluaudite and Fe–Mg-rich muscovite as minor constituents. It was concluded that the composition of the primary fine-grained mineralization in the unaltered (original) bauxite ore was adequate to serve as a source for the much coarser later mineralization in the fracture zones. [Copyright &y& Elsevier]

This study compares the success of vegetative diaspore establishment of the old forest lichens Lobaria pulmonaria and L. scrobiculata sown on Picea abies branches in boreal rainforests. The larger diaspores of L. pulmonaria (green algal photobiont) established more successfully, and showed a greater flexibility in ecological amplitude, than the smaller diaspores of L. scrobiculata (cyanobacterial photobiont). The establishment success apparently depended on species-specific differences in morphological and physiological traits of the diaspores. Both species established as well in young plantations as in old forests. Lobaria scrobiculata was most successful on short branches and small trees. In contrast, L. pulmonaria responded positively to trunk circumference in the old stands. The establishment success of both species decreases with increasing canopy openness, indicating that the soredia/isidioid soredia failed to establish on the most exposed branches. The probability of establishment did not change with bark-pH or with distance from the nearest stream. Despite a successful establishment in regeneration forests, the long-term survival in managed forests is still uncertain. [ABSTRACT FROM AUTHOR]

Hygroscopically active awns or 'bristles' have long intrigued scientists. Experimental evidence shows that they are important for diaspore burial in the correct orientation, thereby increasing successful seed germination and seedling survival. Despite these ecological advantages, 38 of the 280 species of grasses in Danthonioideae lack awns. We provide the first study of awns in a phylogenetic context and show that although the awnless state has arisen ca. 25 times independently, the ecological disadvantage of not having an awn also applies in an evolutionary context. Only in Tribolium and Schismus have awnless ancestors diversified to form a clade of primarily awnless descendents. Several of the awnless species in these genera are annual and we find a significant correlation between the evolution of awns and the evolution of life history. A suite of other diaspore traits accompany the awned or awnless states. We interpret the awn as being the visible constituent of a compound 'burial syndrome,' the two ecological extremes of which may explain the correlation between awns and life history and provide an explanation why awnless species in Tribolium and Schismus persist. [ABSTRACT FROM AUTHOR]

Using ITS nrDNA sequence data, the Caloplaca cerina group (Teloschistaceae) is defined here as a monophyletic, but internally richly branched lineage. The group is also characterized by a combination of morphological and anatomical characters. Its internal lineages are supported by phenotypic characters in addition to ecology and distribution. Within the large C. cerina group, we have found at least 20 phylospecies in the temperate zone of the Northern Hemisphere. Two species complexes do not produce any vegetative diaspores: the polyphyletic, corticolous Caloplaca cerina s. lat. (six separated cryptic or semi-cryptic species) and the monophyletic C. stillicidiorum s. lat. that grows mainly on plant debris, small shrubs and bryophytes and consists of at least four internal lineages. All lineages producing vegetative diaspores (soredia, blastidia, isidia or lobules) are phenotypically characteristic and represent fairly easily distinguishable species: C. chlorina, C. isidiigera, C. monacensis, C. subalpina, C. thracopontica, C. turkuensis and C. ulmorum. Only the North American sorediate C. pinicola possibly represents an aggregate of species. Caloplaca sterilis is described as a new species. A key to the phenotypically distinguishable species is provided.Lectotypes are designated for C. albolutea, Caloplaca cerina f. coronulata and for C. monacensis. The Australian C. hanneshertelii belongs to this group, but this and other possible species from the Southern Hemisphere are not treated here in detail. Some species traditionally placed in the C. cerina group due to their similar morphology are excluded here on the basis of our phenotype examinations and molecular data. Caloplaca albolutea, C. mydalaea and C. virescens are uncertain taxa and their identities still remain unclear. [ABSTRACT FROM AUTHOR]

Abstract: Highly branched waxy maize starch (WMS) was used to separate diaspore from artificial mixtures of diaspore and kaolinite by microflotation using dodecylamine (DDA) as collector. It was found that WMS depressed the diaspore flotation while activated the kaolinite flotation more or less. The adsorption of WMS on diaspore was examined through adsorption test, zeta potential measurement, infrared spectroscopy, and atomic force microscopy. It is suggested that both chemical interaction and intermolecular hydrogen bonding by hydroxyl groups of starch with surface Al–OH moieties occurred in the adsorption. Results obtained from the adsorption of DDA and WMS on diaspore showed that starch virtually enhanced the DDA adsorption. The depressant action of WMS can be rationalized primarily by the formation of hydrophilic adsorption layer enveloping the surface of diaspore and covering the collector. [ABSTRACT FROM AUTHOR]

Manycoastal plant species are widely distributed, including several pan-global species. Long-distance dispersal and physiological resilience of diaspores (i.e. the plant dispersal unit encompassing the seed and any additional surrounding or attached tissues at dispersal) to adverse environmental conditions are possible contributors to the presence of species over hundreds of kilometres of coastline. Dispersal by water (hydrochory) may occur in coastal habitats. This study investigated diaspore traits considered important for oceanic hydrochorous dispersal, including morphology, buoyancy and survival in seawater, and germination under saline conditions for 13 species common to Holocene dune communities in Western Australia. Of the diaspores of 13 species dominant in this coastal community, 11 floated in seawater, with 7 having >50% of diaspores buoyant after 14 days and some diaspores remaining buoyant for 70 days. Of the 10 species that germinated, diaspores of 9 survived exposure to seawater for up to 70 days. Germination of physiologically dormant seeds contained within indehiscent woody fruits and physically dormant seeds was least affected by time in seawater. The effects of varying concentrations of NaCl (0-500 mM) on germination differed between species, but most were able to recover and germinate when transferred to non-saline water. Three different patterns of salt response were observed. It appears likely a combination of diaspore traits, rather than a single factor, facilitate oceanic hydrochorous dispersal. [ABSTRACT FROM AUTHOR]

Flotation reagents are the critical technique in the flotation separation process for desilication. Aimed at the highly selective reagent for direct flotation of diasporic bauxite, a novel compound, dibenzo-1-(7-carboxyl-4-hydroxyl bicycle [2.2.2] octan-7,8-diyl) carboxamic acid (DBCA) with two functional groups carboxyl and hydroxamate in the same molecule, was synthesized through Diels-Alder reaction followed by oximation reaction. Subsequently, the floatability of diaspore, kaolinite, and illite was measured by using DBCA as a collector, the interaction mechanism between minerals and DBCA was investigated through zeta potential measurements and FT-IR spectrum, and the structure and property relationship of the collector were also discussed. The flotation experimental results showed that DBCA had a very strong collecting ability for diaspore, while poor activity was observed for kaolinite and illite. The interaction of DBCA on diaspore surfaces may be mainly dominated by chemical bonding as the formation of three chelation rings; however, those on the surfaces of kaolinite and illite are mainly hydrogen bonding or physical adsorption. Consequently, it is possible to separate diaspore from such aluminosilicates as kaolinte and illite employing DBCA as a collector. [ABSTRACT FROM AUTHOR]

Abstract: Remobilized-origin gem diaspore and related minerals occur as infill within structurally controlled voids that developed in the upper of two distinct karst unconformity-type metabauxite (diasporite) horizons in the İlbir Mountains area of the Milas-Muğla province, SW Turkey. Colour-change diaspore (trademarked as zultanite) and associated mineral specimens (greenish muscovite, chloritoid, donbassite, specular hematite, ilmenite, goethite, and younger calcite) occur in fracture zones (veins and open structures) that cross-cut the metabauxite horizons. The mineralized fracture zones do not extend into the enclosing marbles, probably because of the ductility contrast between the brittle bauxite and relatively plastic carbonate beds. Thick, white to light gray and dark gray limestone beds were deposited in the İlbir Mountains area during the Cretaceous (146–65Ma), and contain two stratigraphically distinct karst-fill bauxite horizons. Al-, Fe-, Si- and Ti-rich solutions that infiltrated the karstified limestone probably originated from altered schist and gneiss that surround the basin. The limestone beds (>2000m thick) were subjected to burial metamorphism, forming marble. Subsequently, the marble block was folded during nappe emplacement toward the SSW as part of late Alpine contractional deformation during the Paleogene (65–23.8Ma). The upper bauxite horizons within the folded block were cross-cut by fracture zones because of their relatively brittle rheology. At this time, increased pressure and temperature in the bauxite horizons resulted in remobilization of the primary constituents of the bauxite within an aqueous complex, resulting in the crystallization of coarse-grained assemblages in the cross-cutting structures. Ultimately, erosion and mineral exploration revealed the steeply dipping bauxite outcrops and mine workings evident today. This paper focuses on the mine geology of surface outcrops of diasporic bauxite, the upper bauxite horizon within underground mine galleries at elevations of 600, 632, 637, 642, 652, 657, and 702m, and in open pits at sites in the Küçükçamlık and Büyükçamlık hills, Milas-Muğla province, SW Turkey. [Copyright &y& Elsevier]

Abstract: Hydrolyzate of hogwash oil (HHO) was prepared at ambient pressure using hogwash oil that was collected from the dietary industry as a raw material by means of non-pressurized multistage hydrolyzation. Before hydrolyzation, the collected hogwash oil was subject to pre-treatment that included deposition edulcoration, acidification degumming and deodorization by digestion as well as vacuum dewatering. Components of the synthesized products were detected by gas chromatography and the results indicated that unsaturated fatty acids are the major components. Using HHO as a collector, the flotation behavior of diaspore and kaolinite was investigated. The reaction mechanisms of diaspore and kaolinite with HHO are discussed based on a zeta potential test. The results showed that a concentrate with a mass ratio of Al2O3 to SiO2 of 14.42 and an Al2O3 recovery of 81.80% can be obtained at a feed mass ratio of Al2O3 to SiO2 of 5. This indicated that the HHO is a potential collector for separating diaspore from aluminosilicate minerals in bauxite. The results also suggested a possible way to reuse discarded hogwash oil to avoid environmental pollution. [Copyright &y& Elsevier]

Abstract: The İlbirdağı diasporic metabauxite (diasporite) deposit of the Milas (Muğla) region of Turkey is a unique deposit including both metamorphic (primary) and hydrothermal-remobilized (secondary) diaspore that formed during different geological periods. Microscopic diaspore crystals with a metamorphic origin are common and are the main constituent of the metabauxite ore, which was metamorphosed during from the Late Cretaceous to Late Paleocene Periods. However, secondary macroscopic diaspore crystals filling fracture zones that crosscut the metabauxite ore formed during the Late Paleocene, Eocene and Oligocene Periods as the result of later hydrothermal solutions that remobilized constituents of the metabauxite. The macroscopic diaspore crystals can be distinguished from the metamorphosed microscopic diaspore crystals, based on size, appearance, occurrence, and origin. Approximately 60% of the macroscopic diaspore crystals have an opaque appearance and pale green coloration and are not considered attractive. By contrast, the other 40% are gem quality and exhibit a marked change in color under different types of illumination. The crystals are mostly olive-green and soil-brown in daylight. A small number of the crystals display color-change, such as green in daylight or equivalent illumination and carmine in low-wattage tungsten lights. X-ray diffraction (XRD) study, using a comparative matching technique, reveals that these Anatolian diaspore (zultanite) crystals [AlO(OH)] are polycrystalline and that their X-ray spectrum includes the overlapped XRD peaks of some mineral inclusions consisting of donbassite [Al5.33Si3O10(OH)8] (di-di-octahedral sheeted Al-rich chlorite), corundum (Al2O3), boehmite [AlO(OH)], quartz (SiO2), ilmenite (FeTiO3), goethite [FeO(OH)] and chloritoid [(Fe, Mg, Mn)2Al4Si2O10(OH)4]. We label these unusual inclusions as sub-microscopic inclusions, because they cannot be seen with a polarizing microscope. Polarizing microscope (PM), scanning electron microscope (SEM), optical absorption (OA), Fourier transform-infrared (FT-IR) and simultaneous differential-thermogravimetric analysis (DTA/TGA) investigations were performed to reveal the mineralogical characteristics of the Anatolian diaspore crystals. [Copyright &y& Elsevier]

Abstract: Three novel carboxyl hydroxamic acids including ortho-carboxyl tetrachlorobenzohydroxamic acid (OCB), ortho-carboxyl hexahydrobenzohydroxamic acid (OHB) and ortho-carboxyl tetrahydrobenzohydroxamic acid (OTB), were synthesized and tested as collectors for flotation of diaspore, kaolinite and illite contained in diasporic bauxite from China. Subsequently, their flotation mechanism to diaspore and aluminosilicate minerals was investigated by zeta potential measurements and FT-IR spectrum checking. The results of flotation experiments show that by using carboxyl hydroxamic acid as collectors, the pulp pH value has significant influence on their collecting performance as the floatability of either diaspore or aluminosilicates varies sharply with their change, and the appropriate pH value for the flotation of diaspore gets close to neutral condition where diaspore presents good floatability while kaolinite and illite exhibits poor performances. Additionally, the floatability of diaspore and aluminosilicates is in the descending order of diaspore, kaolinite, and illite in the presence of three collectors, and their collecting capacity to three minerals is in the ascending order of OTB, OHB and OCB. Of three synthesized carboxyl hydroxamic acids, OCB has the strongest collecting capability to diaspore while relatively weak to aluminoscilicate minerals, whose good selectivity for the flotation between diaspore and aluminosilicates is possibly suited for direct flotation desilication of diasporic bauxite. Moreover, the optimum pH value for diaspore flotation associated with FT-IR spectrum and zeta potentials indicate that the adsorption interaction between the synthesized collectors and diaspore is dominantly a kind of chemical bonding one in the form of three cycle chelate rings due to the coordination of carboxyl and hydroxamate to the metal aluminum atoms, where the oxygen atoms contained in carboxyl and hydroxamate of the polar group have the stereo conditions to form five to seven membered rings. By contrast, the adsorption interactions of the carboxyl hydroxamic acid on the surfaces of aluminosilicate minerals are mainly dominated by means of hydrogen bonds. [Copyright &y& Elsevier]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Jajarm’s bauxite deposits are mainly diasporic, and they have a low mass ratio of Al2O3/SiO2. It is necessary to increase the run-of-mine mass ratio before feeding the material to the Bayer process. Chemical analysis indicated that the low-grade bauxite sample from Jajarm contained 43.9wt% Al2O3 and 13.35wt% SiO2, resulting in a mass ratio of 3.29. According to mineralogical studies, the presence of aluminosilicate minerals such as kaolinite, illite, and quartz was the main reason for the decrease of the mass ratio. Microscopic observations revealed that, with the size reduction from −1000+710 to −38 μm, the liberation degree of diaspore increased from 10% to 60%, and that of aluminosilicates increased from 20% to 85%. Heavy liquids with the densities of 2.8, 3.0, 3.2, and 3.4 g/cm3 were used to evaluate the heavy media separation in three sizes, i.e., −3350+710, −710+212, and −212+125 μm. Laboratory studies confirm that the density of 3.2 g/cm3 can produce the concentrates (in sunk fractions) with recoveries of 89.09%, 91.24%, and 84.68% with the Al2O3/SiO2 mass ratios of 5.03, 5.16, and 5.15 for the −3350+710, −710+212, and −212+125 μm sizes, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Ecoscience (Ecoscience) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The contribution of morphological features of parent thalli, substrate and climatic factors, and their seasonal fluctuations to variation in the viability of vegetative diaspores has been studied on the model of epiphytic lichen Hypogymnia physodes. Seasonal trends in viability have been revealed only in certain types of biotopes. Hygrothermal conditions and substrate properties in the biotope have proved to have a significant effect on the viability of soredia. [ABSTRACT FROM AUTHOR]

Abstract: Fire opal (SiO2·nH2O) and diaspore [Al(OH)O] are two different precious and rare mineral species with high water content. While these species are being cut and polished to make gems, defect-induced weaknesses such as fragility, splintering, and cracking become apparent since the temperature of the mineral species may be increased to high temperatures during the process. These deformations may be broadly related to water loss (molecular (H2O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals. In this study, thermal properties and thermal stability as dehydratial behaviors of both gem quality fire opal (SiO2·nH2O) from the Şaphane region (Kütahya, Turkey) and gem quality diaspore (AlOHO) from the Milas region (Mug˘la, Turkey), including some associated mineral inclusions, were studied by means of X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform-Infrared absorption (FTIR) spectroscopy and thermal analysis (DTA/TGA). During heating to 1400°C, DTA/TGA patterns indicated that the weight losses of the fire opal and diaspore were due to the water loss only, and that these losses occur in the temperature ranges between about 342 and 722°C in fire opal, and between about 592 and 718°C in diaspore. In addition, after making some corrections concerning the mass gain observed, being due to the drift with buoyancy effect of the atmosphere, in their TGA curves, the fire opal shows a mass loss of 7.942%, and one distinctive sharp endotherm at 1089.99°C and seven weaker endotherms, whereas the diaspore shows a mass loss of about 13.826%, and one distinctive sharpest endotherm at 650.47°C and four weaker endotherms. [Copyright &y& Elsevier]

The Jajarm bauxite deposit, northeast Iran, is the largest such deposit in Iran. The deposit is sandwiched between the Triassic Elika formation and the Jurassic Shemshak formation, housed within karstic features developed within the former unit. The deposit generally shows an internal layering defined by the following four distinct horizons (from bottom to top): (a) a lower argillaceous horizon, approximately 50-80 cm thick, is mainly composed of clay minerals that directly overlies the carbonate footwall (Elika formation); (b) a bauxitic clay layer approximately 2-3 m thick that consists mainly of hematite, kaolinite, anatase, and diaspore; (c) a red bauxite layer (the main high-grade ore), about 5 m thick and composed of diaspore, kaolinite, anatase, and hematite; and (d) an upper kaolinitic layer that is 20- 50 cm thick, composed mainly of kaolinite, and overlain by the Shemshak formation. Detailed petrographic studies reveal diagenetic alteration of the bauxitic protolith. The main observed bauxite textures are microgranular, oolitic, pisolitic, fluidal-collomorphic, and microclastic. Microgranular and microclastic textures associated with the residual fractured and corroded quartz grains, as well as feldspar grains are almost completely replaced by platy diaspore. Geochemical analyses of the red bauxite reveal enrichment of less mobile elements (Nb, Th, Zr, Mo, Ga, and Cr) and depletion of mobile elements (Rb, K, Na, Sr, La, Mg, and Pb); the opposite result is obtained for the bauxitic clay. Chondrite-normalized REE (Rare Earth Element) patterns for the upper kaolinite layer are similar to those for the underlying red bauxite, and the patterns obtained for the lower argillaceous layer are similar to those for the overlying argillaceous bauxite horizon. Ce shows a positive anomaly in the red bauxite and a negative anomaly in the bauxitic clay. The correlation coefficients calculated between REE and other elements demonstrate that the likely REE-bearing minerals are oxides of Ti and Nb, clay minerals, and zircon. In contrast to the present diasporic mineralogical composition of the Jajarm bauxite, the geochemical and mineralogical data indicate an original gibbsitic composition. Finally, the observed mineralogical and textural evidence, combined with the evidence provided by variation diagrams and REE patterns, indicates a mixed origin for the Jajarm bauxite from both basic igneous and sedimentary rocks. In fact, bauxitization was initiated on basic source rocks and continued during reworking and replacement within the karstic features. [ABSTRACT FROM AUTHOR]

Background and Aims: Initial release height and settling speed of diaspores are biologically controlled components which are key to modelling wind dispersal. Most Sphagnum (peat moss) species have explosive spore liberation. In this study, how capsule and spore sizes affect the height to which spores are propelled were measured, and how spore size and spore number of discharged particles relate to settling speed in the aspherical Sphagnum spores. [ABSTRACT FROM PUBLISHER]

Abstract  Several m-thick, karst-unconformity-type metabauxite horizons in the İlbir Mountains of SW Turkey host open-space mineralization of gem-quality diaspore (trademarked as zultanite), associated with muscovite, hematite, ilmenite, chloritoid, and younger calcite. The hydrothermal-metamorphogenic mineralization occurs in fracture zones (veins and open structures) that crosscut the metabauxite horizons, but does not extend into the marble host rocks. The white to dark gray marble sequence (over 2,000 m in thickness) is of Cretaceous depositional age and was affected by Alpine (Paleogene) tectonometamorphism which caused the hydrothermal remobilization of primary bauxite components into crosscutting structures. [ABSTRACT FROM AUTHOR]

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Bryophyte diaspore banks are a potential source of reproductive propagules that may be able to colonize newly available habitat after forest harvesting. However, their role and the factors influencing the successful establishment of species remain poorly understood. To investigate these aspects of diaspore banks, we obtained mineral soil samples from mixed and coniferous stands of boreal mixed-wood forest in northern Alberta, Canada, which had recently experienced a range of harvesting intensities. Samples were germinated in growth cabinets under two light regimes. The composition of germinated bryophyte species was compared among forest types, harvesting intensities, and light levels, and also related to edaphic conditions and geographic location of the sample site. Germinated species composition was not related to forest type or harvesting intensity, but was associated with measured edaphic variables and geographic space, indicating that similarity in species composition reflected similarity in edaphic conditions and spatial proximity. This was partly because of spatial dependence of edaphic variables. Light intensity had a significant influence on the development of species assemblages and individual species responses. Richness and cover of acrocarpous mosses (fugitive, colonist, and shuttle life-history strategies) were significantly reduced under low light conditions, but pleurocarpous mosses (perennial strategy) were not affected. Shannon diversity and the frequency of reproduction were significantly greater with high light. Pleurocarpous mosses that are characteristic of intact forests germinated frequently, suggesting that diaspore banks may influence their recovery after disturbance. Diaspore banks are a repository of species at sites affected by forest harvesting; however, diaspore germination and establishment will be constrained by the local environment, including edaphic conditions and light intensity. [ABSTRACT FROM AUTHOR]

Abstract: Among the 17 genera in the southern African tribe Arctotideae (Asteraceae), only the three genera of subtribe Gorteriinae (Cuspidia, Gorteria and Didelta) have capitula that function as diaspores. The feature is reported here also in the genus Hirpicium for the first time. The discovery supports recent phylogenetic studies of the group that Hirpicium integrifolium and H. alienatum are more closely related to Gorteria than to the rest of the Hirpicium species. [Copyright &y& Elsevier]

Abstract: A new environmentally friendly design for low-grade diasporic-bauxite processing which is different from the Bayer and sintering processes was proposed in this paper. In the redesign of alumina production technology, a mixture of bauxite ore and sodium hydroxide solution was heated at a higher temperature for the purpose of complete decomposition of bauxite. The products were then extracted by water; the resulting sodium aluminate solution was further purified and used for the gibbsite precipitation, the residue being reacted with a caustic liquor to recover sodium oxide and alumina. The experimental results show that during the new process bauxite decomposition rates approach 100% and the residues can be easily recovered. When diasporic ores with mass ratio of alumina to silica of approximately 5:1 are treated, total alumina recovery efficiency of 86% and a sodium oxide presence below 1.5% in the final red mud will be achieved. This new design surpasses previous approaches in terms of high resource efficiency and low environmental impact. [Copyright &y& Elsevier]

The removal rates of fruits (the diaspore) were assessed in exclusion experiments in three shrubby species of Darwinia, endemic to the Sydney Basin of south-eastern Australia. There was a clear pattern of fruit removal in just a few days by small species of ants from the genera Iridomyrmex, Crematogaster and Pheidole. When only ants had access to fruits an average of 41% of fruits were removed, whereas when only vertebrates had access an average of 13% of fruits were removed. There was some variation in the number of fruits removed both between species and within species across study sites or annual seed crops. When ants had access to seeds this variation in removal amounted to 10–80% over 1–4 days. Uniquely in Darwinia, it is the old petals (which remain attached to the fruit) that are attractive to the ants, rather than a specific lipid body. This likely represents a case of successful ecological fitting by Darwinia to take advantage of the widespread presence of myrmecochory in the Australian flora. [ABSTRACT FROM AUTHOR]

Abstract: The utilization of a non-toxic natural polysaccharide, soluble starch, in the flotation of diaspore and kaolinite with emphasis on depression of diaspore in the reverse flotation of bauxite ores by using a Gemini cationic collector, is reported in this work. Firstly, the depressant effect of soluble starch was studied by pure mineral micro-flotation of diaspore and kaolinite as functions of the depressant dosage and pulp pH. The results show that soluble starch depresses diaspore much better than kaolinite. When pH is over 10, a satisfactory separation of the alumina and the silicate minerals can be approached. Moreover, micro-flotation tests of artificial mixed minerals and bench scale reverse flotation of the diasporic bauxite ore was complementing conducted. The non-charged starch is highly proved to be an effective and selective depressant for the reverse flotation of diaspore from the gangue minerals like kaolinite. By zeta potential measurement, adsorption studies and D-IR spectra analysis, the mechanism of interaction between starch and the diaspore surfaces is established, which is the formation of a five membered ring complexes on mineral substrates. The number of broken Al–O bonds of diaspore is much more than that of kaolinite, so the selectivity separation of diaspore from kaolinite in this system is feasible. [Copyright &y& Elsevier]

Epizoochory is the mode of seed dispersal where a diaspore (disseminating plant propagule) is disseminated on the external surface of an animal. While the structures that facilitate diaspore adherence are diverse, epizoochory is considered to be relatively rare (approximately 10% of angiosperms), but is commonly utilized by several invasive plant species. We experimentally sought species specific associations between the adherence and retention of eight common plant species' diaspores and five mammalian furs, plus human clothing. We sought relationships between both fur and diaspore characteristics in both the adherence and retention of diaspores. Diaspores of Geum aleppicum were the only ones interacting significantly better with one kind of substrate (mouse fur) than diaspores of all other plant species by being retained well in mouse fur. Alternatively, bison fur behaved as a "generalist" disperser, by consistently accommodating the adherence and retention of a wide range of diaspore morphologies. Finally, exotic plant species displayed a higher tendency than natives to adhere to a variety of mammal fur types, indicating a more flexible dispersal strategy for the invasive habit. [ABSTRACT FROM AUTHOR]

Comprehensive studies have established that ShPDM-45 refractory produced by OAO Zaporozhogneupor exhibits good anticorrosion properties towards the action of electrolysis bath corrosive extraneous components. The degree of degradation of ShPDM-45 refractory after two years of service is 10%. The average concentration of entry of Nag and Ftot into ShPDM-45 refractory through hearth blocks with 50% graphite is correspondingly 4.08 × 10–4 and 3.32 × 10–4 g-mole/day. It is established that ShPDM-45 refractory is a more reliable barrier material than unmolded aluminosilicate mixes. The penetration rate of corrosive components of the electrolysis bath into unmolded aluminosilicate materials is greater by a factor of 10 – 30 than for ShPDM-45 refractory. It is shown that the protective function of titanium-containing components and glass phase in an electrolyzer lining develops as a result of forming fluoride, subfluoride and oxyfluoride titanium compounds. Industrial approval of ShPDM-45 refractory under OAO Zaporozhe Aluminum Combine conditions has shown that it exhibits good operating properties in electrolyzers with hearth blocks with 50% graphite [ABSTRACT FROM AUTHOR]

In the attempt to ensure long-term-conservation of flood meadows along the northern Upper Rhine transfer of seed-containing plant material was successfully applied since 2000. In this highly dynamic habitat, many typical plant species rely on a persistent seed bank for re-establishment after disturbance. But in contrast to the re-established above ground vegetation, seed bank composition remains unknown. Thus the main aims of the study were to elucidate the current seed bank composition and to assess patterns of seed and species traits. To this end we sampled above ground vegetation and seed bank on plant material plots and on control plots left to natural recruitment. Although the seed bank was still dominated by agrestal and ruderal plant species, it already contained seeds of transferred species. Analyses revealed that on the plant material plots seed density of plant material species declined significantly with soil depth, just as similarity between above ground vegetation and seed bank declined. In contrast, the seed bank on control plots comprised significantly lower numbers of transferred species. We found a vertical pattern of seed bank composition: in general, the upper seed bank layer comprised more elongated and large seeds of long-lived, competitive species able to build up transient seed bank. The lower soil layer was dominated by seeds of short-lived, agrestal and ruderal species, producing small, round and long-term persistent seeds. The present study shows that the build up of a seed bank typical of flood meadows is a time-consuming process. Thus restorative management in the early phase of vegetation development should focus on fostering high seed production of transferred species. [Copyright &y& Elsevier]

Question: Does shifting cultivation contribute to plant diversity in an Afrotropical semi-deciduous forest lacking large-scale natural disturbance? Location: Sanaimbo forest, Côte d'lvoire (Ivory Coast). Methods: We surveyed species assemblages, structural attributes of diversity, and life-history traits along a 30-year chronosequence of abandoned fields, comparatively to old- growth and selectively logged forest stands. Results: Patterns of species assemblages strongly changed with fallow area age, with respect to species' light requirements, suggesting niche partitioning along the successional gradient. Species richness, diversity and equitability were all increasing along this gradient. There were clear shifts in life-history traits spectra as the forest recovered, especially regarding leaf shape, lifespan and hairiness, diaspore dispersal, seed size, resprouting capacity, and life forms. Early colonization by the invasive Chromolaena odorata did not appear to impair secondary succession. Soil type influenced old-growth forest vegetation but not fallow vegetation. After 30 years of forest regrowth, plant communities exhibited endemism rates similar to those of ancient forests. Conclusions: Shifting cultivation appears to be a sustainable land use when small-sized fields are embedded in a forest matrix and when agriculture lasts only one to few years, preserves remnant trees, excludes fire and keeps several years between two clearing episodes. It may even contribute to the high biodiversity maintenance at the whole forest scale, by conserving the successional mosaic. However, conservation of old-growth forest patches is required for a number of climax tree species. [ABSTRACT FROM AUTHOR]

Several expected correlations among followed internal plant traits were confirmed using the dataset of 492 herbaceous species from the temporal zone of Central Europe. Average diaspore weight (seed mass), reproductive capacity of population (number of produced diaspores), species height, and ability of lateral spread were the plant traits considered. The evident correlations were confirmed among all investigated traits: (i) The reproductive capacity of population negatively correlated with diaspore weight, plant height, and vegetative propagation. The diaspore weight and their number are closely correlated and co-adapted. (ii) Bigger plant species produce bigger diaspores. These trends are obvious at the inter- and intra-family levels. (iii) Larger plant species showed higher ability to vegetative propagation. [ABSTRACT FROM AUTHOR]

Abstract: The high-pressure elasticity of diaspore (AlOOH) has been determined by Brillouin spectroscopy to 12GPa in diamond anvil cells. Experiments were carried out using a 16:3:1 methanol–ethanol–water mixture as pressure medium, and ruby as pressure standard. Acoustic velocities were measured in three roughly orthogonal planes at ambient and eight elevated pressures. The nine individual elastic stiffness constants of the orthorhombic crystal were obtained by fitting the velocity data to Christoffel''s equation. Aggregate elastic moduli and pressure derivatives were calculated from the C ij s by fits to Eulerian finite strain equations, yielding: , G 0 =117.2(5)GPa, for the Voigt–Reuss–Hill average. All individual C ij s increase with pressure but C 23 and C 55 exhibit anomalously low pressure derivatives. From calculated linear compressibilities, the a-axis is the most compressible. The b-axis becomes the least compressible axis at high pressures. Over the examined pressure range, the azimuthal P-wave anisotropy decreased from 22% to 16%, while the azimuthal S-wave anisotropy increased from 15% to 21%. Both volume and axial compression curves calculated using our Brillouin results are in good agreement with the results from static compression studies. High-pressure sound velocities in diaspore exceed those of other hydrous minerals as well as many anhydrous phases relevant to Earth''s upper mantle. [Copyright &y& Elsevier]

Abstract: The effect of cationic groups on performance of 12-carbon chain collectors in flotation separation of diaspore from kaolinite, pyrophyllite and illite has been investigated by flotation tests and explained by density functional computations. The flotation test results indicated that the separation of diaspore from these aluminosilicate minerals was feasible at strong alkaline conditions by using cationic collectors, dodecylamine chloride (DDAC), dodecyl trimethyl ammonium chloride (DTAC) or dodecylguanidine sulfate (DDGS), respectively. In strong alkaline conditions, these three collectors showed excellent selectivity against diaspore, however, DDGS returned superior collecting ability for aluminosilicate minerals compared with DDAC and DTAC. By using the density functional theory (DFT), we calculated some properties such as the H and N atomic charges and cationic group charges which are related to the reactive behavior of 12-carbon chain collectors at B3LYP/6-31G (D) level. The results of calculations indicated that the efficiencies of these three cationic collectors depend on the investigated parameters, and DDGS is better than DDAC and DTAC as a collector agent. The theoretically obtained results are consistent with the flotation tests. [Copyright &y& Elsevier]

The relationship between biodiversity and habitat productivity has been a fundamental topic in ecology. Although the relationship between these parameters may exhibit different shapes, the unimodal shape has been frequently encountered. The decrease in diversity at high productivity has usually been attributed to competitive exclusion. We suggest that evolutionary history and dispersal limitation may be even more important in shaping the diversity–productivity relationship. On a global scale, unimodal diversity–productivity relationships dominate in temperate regions, whereas positive relationships are more common in the tropics. This difference can be accounted for by contrasting evolutionary history. Temperate regions have smaller species pools for productive habitats since these habitats have been scarce historically for speciation, while the opposite is true for the tropics. In addition, dispersal within a region may limit diversity either due to the lack of dispersal syndromes at low productivity or the low number of diaspores at high productivity. Thereafter, biotic interactions (competition and facilitation) can shape the relationship. All these processes can act independently or concurrently. We recommend that the common approach to examining empirical diversity–environmental relationships should start with the role of large-scale processes such as evolutionary history and dispersal limitation, followed by influences associated with ecological interactions. [ABSTRACT FROM AUTHOR]

Abstract  Thermogravimetric analysis (TGA) testing was used to measure the change in weight of polished samples of Al–XSi (X = 0 and 1.2 mass%) alloys. The samples were heated at 843 K for 6 h in dry air or nitrogen gas. X-ray diffraction was used to monitor the formation of the oxide films on the surface of the samples. The surface oxide films were more compact after the Al alloy samples were heated in air, and the oxide films showed some cracks after being heated in nitrogen gas. The thermally formed surface oxide films on the Al–1.2 mass% Si alloy samples heated in air and in nitrogen gas possessed loose structures, which comprised mainly γ-alumina, diaspore, and gibbsite, along with metallic silicon and/or aluminum. The weight variation curve of the films appeared serrated; this can be attributed to chain reactions (3Si + 3O2 → 3SiO2 + 4Al → 3Si + 2Al2O3) that occurred within the film. [ABSTRACT FROM AUTHOR]

Abstract: Beneficiation of a diasporic-bauxite ore by selective flocculation with sodium polyacrylate (PAS) was studied. Flocculation behaviors of diaspore, kaolinite, illite and pyrophyllite in the presence of PAS were also investigated by sedimentation tests. PAS shows good selectivity for the flocculation separation of diaspore from silicates in the range of pH 8–12. A concentrate with Al2O3/SiO2 ratio 8.9 and the recovery of Al2O3 87.0% was obtained from a diasporic-bauxite ore with Al2O3/SiO2 ratio 5.7 with the addition of sodium carbonate 5kg/t and PAS 7g/t. Micro-photogram, zeta potential and FTIR measurements were then performed to study the mechanisms. It was observed that the zeta potentials of diaspore shifted to negative value strongly and the isoelectric point (IEP) of diaspore was also changed from about pH 6–4, and the flocs of diaspore were larger and denser than that of kaolinite in the presence of PAS. A new band at 1640cm−1 was found in the infrared spectrum of the diaspore after interaction with PAS, and this new band matched the characteristic peak at 1624cm−1 in the infrared spectrum of the reaction products of PAS and AlCl3. The adsorption of PAS on diaspore is concluded to be chemisorption caused by the chemical reaction between carboxylate group and the exposed Al sites on diaspore surface. [Copyright &y& Elsevier]

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4- anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2·nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on AI (hydr)oxides [diaspore (α-AIOOH) and corundum (α-AI2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (Mössbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). Mössbauer measurements revealed that the Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redoxproducton corundum was similar to Tc(IV) oxyhydroxide, TcO2·nH2O. [ABSTRACT FROM AUTHOR]

The adsorption of Cu(II) and Cr(VI) on diaspore was studied with the help of X-ray diffraction analysis, BE measurement, zeta potential measurement and atomic adsorption spectrometry. The adsorption equilibrium almost reaches within 60 min. The adsorption isotherms of Cu(II) and Cr(VI) could be well described by the Langmuir equation. The adsorption capacities o Cu(II) and Cr(VI) are 1.944 and 1.292 mg/g, respectively. The adsorption percentage of Cr(II) increases with the increment solution pH, but the adsorption percentage of Cr(VI) decreases. This could be explained by zeta potential theoretical and electrostatic attraction between metal ions and diaspore surface. [ABSTRACT FROM AUTHOR]

1. The role of collisions with vegetation elements in seed dispersal by wind has been examined only anecdotally. In particular, the idea that the effect of collisions in dispersal may depend on the aerodynamic class of the diaspore has not been broached. 2. We adapted a collision model for small particles to predict the probability of a winged or plumed seed colliding with a vegetation element as a function of the Stokes number (a dimensionless parameter which quantifies inertial tendency and includes diaspore terminal velocity, wind speed and diameter of the target element). 3. We performed experimental releases of seeds upwind of tree boles in two deciduous forest types (temperate and dry tropical) for 10 mid-latitude and tropical species to test the collision model. The model was a reasonable expression of collision efficiency. At higher Stokes numbers, collisions were far more likely for seeds than for water droplets or other small particles. 4. Experimental releases were used in both forests to determine the effect of collisions with boles on distance travelled for several species. Seeds of the three species with asymmetric wings had significantly reduced dispersal following collisions; the single species with plumed seeds did not. 5. In a leafless tropical forest, we experimentally determined the frequency distribution of collisions per metre of travel for seeds released from a canopy. Approximately one collision occurred for every 2 m of flight through the volume occupied by branches and lianas. Distance achieved by asymmetric samaras was relatively unaffected by collisions with small vegetation elements, because the samaras quickly readopted stable autorotation. Conversely, bilaterally symmetric samaras had their dispersal greatly reduced. 6. Synthesis. The effect of collisions on dispersal depends on aerodynamic type. Collisions with small vegetation elements in forests should be more common for samaras than for plumed seeds, because plumed seeds generally have lower terminal velocities. Among winged seeds, collisions with branches will not seriously reduce dispersal except for bilaterally symmetric diaspores, because they are unable to rapidly regain stable autorotation. Reduction in dispersal due to collisions with boles will be unimportant because bole collisions, unlike branch collisions, are rare. [ABSTRACT FROM AUTHOR]

Tertiary amine was synthesized from fatty amine and formaldehyde. And then the synthesized tertiary amine was used to react with benzyl chloride to synthesize hexadecyl dimethyl benzyl ammonium chloride (1627) at ambient pressure. Using the synthesized 1627 as collector, the flotation properties of diaspore and kaolinite were investigated by single mineral and mixed mineral test. The flotation mechanism of diaspore, kaolinite and 1627 was discussed based on FTIR spectra. The results show that the mass ratio of aluminum to silicate achieves 15.02 and the recovery of alumina in concentrate is 43.07% using 1627 as a collector. The 1627 is found to be a more effective and a promising collector for reverse flotation to remove aluminum-silicate minerals from bauxite. [ABSTRACT FROM AUTHOR]

Propagule banks are assumed to be able to store considerable genetic variability. Bryophyte populations are expected to rely more heavily on stored propagules than those of seed plants due to the vulnerability of the haploid gametophyte. This reliance has important implications for the genetic structure and evolutionary potential of surface populations. A liverwort, Manniafragrans, was used to test whether the bryophyte diaspore bank functions as a "genetic memory." If a diaspore bank is capable of conserving genetic variability over generations, the levels of genetic diversity in the soil are expected to be similar or higher than at the sur- face. Surface and diaspore bank constituents of two populations of M. fragrans were investigated. Genetic structure and diversity measured as unbiased heterozygosity were analyzed using three ISSR markers. Similar genetic diversities were found in the soil (H~ = 0.067) and at the surface (H~= 0.082). However, more haplotypes and specific haplotype lineages were present in soil samples. The results suggest that the bryophyte diaspore bank has an important role in accumulating genetic variability over generations and seasons. It is postulated that the role of the diaspore bank as a "genetic memory" is especially important in species of temporarily available habitats that have long-lived spores and genetically variable populations. [ABSTRACT FROM AUTHOR]