Heavy Grains Research Articles

Concentration distribution and assessment of heavy metals in surface sediments in the Zhoushan Islands coastal sea, East China Sea

In an effort to assess the potential contamination and determine the environmental risks associated with heavy metals, 51 surface sediment samples (0–4 cm) were collected in the Zhoushan Islands coastal sea of the East China Sea (ECS). The heavy metal concentrations, grain size and total organic carbon (TOC) contents of these surface sediments were comprehensively analyzed. The results showed that the order of the average concentrations of heavy metals is Zn > Cr > Cu > Pb > As > Cd > Hg. Zn, Cr, Cd and Hg exhibit similar distribution and which derived from a common source, however, Cu, Pb and As present different distribution. The metal enrichment factor (EF) and geoaccumulation index (Igeo) values both suggest that Cu and Cd likely pose environmental risks. The results of this study could provide scientific data to authorities in charge of sustainable marine management.

Automated Indicator Mineral Analysis of Fine-Grained Till Associated with the Sisson W-Mo Deposit, New Brunswick, Canada

Exploration under thick glacial sediment cover is an important facet of modern mineral exploration in Canada and northern Europe. Till heavy mineral concentrate (HMC) indicator mineral methods are well established in exploration for diamonds, gold, and base metals in glaciated terrain. Traditional methods rely on visual examination of >250 µm HMC material. This study applies mineral liberation analysis (MLA) to investigate the finer (<250 µm) fraction of till HMC. Automated mineralogy (e.g., MLA) of finer material allows for the rapid collection of precise compositional and morphological data from a large number (10,000–100,000) of heavy mineral grains in a single sample. The Sisson W-Mo deposit has a previously documented dispersal train containing the ore minerals scheelite, wolframite, and molybdenite, along with sulfide and other accessory minerals, and was used as a test site for this study. Wolframite is identified in till samples up to 10 km down ice, whereas in previous work on the coarse fraction of till it was only identified directly overlying mineralization. Chalcopyrite and pyrite are found up to 10 km down ice, an increase over 2.5 and 5 km, respectively, achieved in previous work on the coarse fraction of the same HMC. Galena, sphalerite, arsenopyrite, and pyrrhotite are also found up to 10 km down ice after only being identified immediately overlying mineralization using the >250 µm fraction of HMC. Many of these sulfide grains are present only as inclusions in more chemically and robust minerals and would not be identified using optical methods. The extension of the wolframite dispersal train highlights the ability of MLA to identify minerals that lack distinguishing physical characteristics to aid visual identification.

Silencing of an Ubiquitin Ligase Increases Grain Width and Weight in indica Rice

Many quantitative trait loci (QTLs) have been identified by molecular genetic studies which control grain size by regulating grain width, length, and/or thickness. Grain width 2 (GW2) is one such QTL that codes for a RING-type E3 ubiquitin ligase and increases grain size by regulating grain width through ubiquitin-mediated degradation of unknown substrates. A natural variation (single-nucleotide polymorphism at the 346th position) in the functional domain-coding region of OsGW2 in japonica rice genotypes has been shown to cause an increase in grain width/weight in rice. However, this variation is absent in indica rice genotypes. In this study, we report that reduced expression of OsGW2 can alter grain size, even though natural sequence variation is not responsible for increased grain size in indica rice genotypes. OsGW2 shows high expression in seed development stages and the protein localizes to the nucleus and cytoplasm. Downregulation of OsGW2 by RNAi technology results in wider and heavier grains. Microscopic observation of grain morphology suggests that OsGW2 determines grain size by influencing both cell expansion and cell proliferation in spikelet hull. Using transcriptome analysis, upregulated genes related to grain size regulation have been identified among 1,426 differentially expressed genes in an OsGW2_RNAi transgenic line. These results reveal that OsGW2 is a negative regulator of grain size in indica rice and affects both cell number and cell size in spikelet hull.

Depositional process of the Byk‐E tephra bed in the Chiba section, central Japan: A marker bed defining the Global Boundary Stratotype Section and Point for the Chibanian Stage

AbstractThe global boundary stratotype section and point (GSSP) for the Chibanian Stage and Middle Pleistocene Subseries is present at the base of the Byk‐E tephra bed in the Chiba section, located in the central Boso Peninsula, Japan. The Byk‐E tephra bed, which erupted from the older Ontake Volcano, is a conspicuous marker bed in the Chiba section; therefore, it provides a clear local and regional marker for the GSSP. However, the sedimentological characteristics of the Byk‐E tephra bed have not been well documented. Here, we provide a detailed description and an isopach map of the Byk‐E tephra bed based on the lithofacies, grain‐size compositions, and grain orientations in the Chiba section and other localities in the Boso Peninsula. The lithofacies and grain size compositions of the tephra bed show that the lower part of the bed show no evidence of flow‐induced deposition. These results suggest that the Byk‐E tephra bed is most likely deposited as fallout deposits under a weak bottom current that could not direct the heavy mineral grains. Therefore, the Byk‐E tephra bed is not to erode the underlying bed during the deposition, indicating that there is no stratigraphic discontinuity. The isopach map drawn from the observed thickness of the fallout unit, show that the distribution of the Byk‐E tephra extends more than 260 km but a limited azimuthal range.

Bioturbation, heavy mineral concentration, and high gamma-ray activity in the Lower Cretaceous McMurray Formation, Canada

In the Lower Cretaceous McMurray Formation (Alberta, Canada), many intervals of intensely bioturbated (Bioturbation Index = 5–6) fine-grained sediments are characterized by high gamma-ray (GR) readings. Several methods, including sedimentary facies analysis, thin-section petrography, handheld spectral gamma-ray, portable X-ray fluorescence, X-ray diffraction, inductively coupled plasma-mass spectrometry, microprobe of K-feldspar, energy dispersive spectroscopy, and detrital zircon geochronology by laser ablation-inductively coupled plasma-mass spectrometry, were used to investigate the interval of interest in core samples. The mineralogical analysis shows that these intervals are enriched in heavy mineral grains, and particularly in zircons. The content of radioactive elements is variable. Thorium is commonly elevated up to three times, uranium nil to two times, and potassium content usually remains normal. The studied intervals consist of interbedded, bitumen-saturated cross-bedded and/or ripple cross-laminated sandstone (high-energy deposits) and light-gray bioturbated mudstone (low-energy deposits), commonly addressed as inclined heterolithic strata (IHS). IHS represent tidally influenced, brackish-water, upper point-bar deposits. The zircon grains become concentrated while hydraulic processes interact with bioturbation: the burrowing animals cause significant sediment mixing that allows the lightest sediment particles to go back into the suspension. Additionally, bioturbation increases the surface roughness along the sediment-water interface and, causes more turbulent flow, allowing for quartz and other light grains to be removed by traction and/or saltation, while dispersed heavier zircon grains become trapped and concentrated in open burrows.So far, this study is the first to demonstrate the importance of bioturbation in the enrichment of zircon grains in IHS. The interaction of bioturbation and hydraulic processes explains the apparently counter-intuitive enrichment of heavy minerals in a low-energy depositional setting. This scenario likely applies to numerous intervals characterized by similar GR and/or zirconium spikes across the McMurray Formation. Furthermore, it can be expected that in other sedimentary basins and stratigraphic units, similar studies will demonstrate that the proposed mechanism is universal.

Provenance, clastic composition and their impact on diagenesis: A case study of the Oligocene sandstone in the Xihu sag, East China Sea Basin

Sandstone composition, heavy mineral analysis, and bulk rock geochemistry analyses were used to investigate the provenance lithotypes and sediment transport pathways of the third, fourth, and fifth (E3h3, E3h4 and E3h5) members of the E3h Formation at the gas–reservoir scale in the Xihu sag, East China Sea Basin. In addition, the diagenetic features and porosity of the metamorphic-sourced and volcanic-sourced sandstones were investigated. The provenance lithotypes of the E3h3, E3h4, and E3h5 were mainly medium–low grade metamorphic rocks and felsic to intermediate volcanic rocks. The sediment transport pathways were from northeast to southwest and from east to west, indicating that the E3h3, E3h4 and E3h5 members had two sediment provenance, namely, the metamorphic rocks of the northern Hupijiao Rise and the volcanic rocks of the eastern Diaoyudao Rise. Then the sedimentary microfacies distribution of the E3h3, E3h4, and E3h5 members and its relationship with the dual provenance sedimentary system were determined by using the heavy mineral assemblages, ZTR index, grain sizes, lithic fragments and quartz content. The initial porosity values of the metamorphic-sourced medium-grained and fine-grained sandstones were 35.35% and 35.22%, respectively; while the initial porosity values of the volcanic-sourced medium-grained and fine-grained sandstones were 34.09% and 34.97%, respectively. The average porosity compaction loss percentages were mainly 80.2% and 86.91% for the metamorphic-sourced medium–grained and fine–grained sandstones, and 86.95% and 87.23% for the volcanic-sourced medium–grained and fine–grained sandstones. The contact types of mineral grains in the metamorphic-sourced sandstones were mainly punctual, linear and concave-convex contacts; while the contact types of mineral grains in the volcanic-sourced sandstones were mainly linear, concave-convex, and sutured contacts. The metamorphic-sourced sandstone mainly developed chlorite coats; while the volcanic-sourced sandstones mainly contained pore-filling chlorite. The average quartz cement contents were 0.83% and 0.61% for the metamorphic-sourced medium–grained and fine–grained sandstones, and 0.67% and 0.43% for the volcanic-sourced medium–grained and fine–grained sandstones. The illite, mixed-layer illite/smectite and calcite cement reduced the sandstone porosity by filling pores. The metamorphic–sourced sandstones mainly developed primary intergranular pores and intergranular dissolved pores; while the volcanic–sourced sandstones mainly developed intergranular dissolved pores, intragranular dissolved pores, and moldic pores. The metamorphic-sourced sandstones had a higher porosity than the volcanic-sourced sandstones with the same grain size, which the difference in their porosities reached 1–3%.

The Effect of Photoperiod Genes and Flowering Time on Yield and Yield Stability in Durum Wheat.

This study analysed the effect of flowering time as influenced by photoperiod sensitivity genes on yield and yield stability in durum wheat. Twenty-three spring genotypes harbouring different allele combinations at Ppd-A1 and Ppd-B1 were grown in 15 field experiments at three sites at latitudes from 41° to 19° N (Spain, Mexico-North and Mexico-South). Low temperature and solar radiation before flowering and long day length during grain-filling characteristic for the Spanish site resulted in high grain number/m2 (GN) and yield (GY), while a moderate GN combined with high solar radiation during grain-filling at Mexico-North led to heavier grains. Allele combination GS100-Ppd-A1a/Ppd-B1a reduced the flowering time up to nine days when compared with Ppd-A1b/Ppd-B1a. Differences in flowering time caused by Ppd-A1/Ppd-B1 allele combinations did not affect yield. Combinations GS105-Ppd-A1a/Ppd-B1b and Ppd-A1b/Ppd-B1b resulted in the highest GN, linked to spikelets/spike, which was higher in GS105-Ppd-A1a/Ppd-B1b due to more grains/spikelet. Flowering time caused by Eps had a minor effect on GN, spikes/m2 and grains/spike, but late flowering resulted in reduced grain weight and GY. Allele combinations harbouring alleles conferring a similar photoperiod sensitivity response at Ppd-A1 and Ppd-B1 resulted in greater yield stability than combinations that carry alleles conferring a different response. Allele combination GS100-Ppd-A1a/Ppd-B1a was the most suitable in terms of yield and yield stability of durum wheat cultivated under irrigation within the studied latitudes.

THE IMPACT OF SEASONAL CHANGES ON HEAVY MINERALS CONCENTRATION FROM A PART OF EAST COAST OF INDIA

Pre and post monsoonal changes in the environment have led to a noticeable variation in sediment characteristics, heavy mineral concentrations and their distribution. The current study aimed to find out the effect of seasonal fluctuations on the concentration of heavy minerals along the coast and the variations in sediment textures and distribution. The study has revealed the effect of seasons on the sediments supply and its distribution along coast in the study area. The total heavy minerals concentrations are more in post monsoon than in pre monsoon and the concentration also increases from south to north in parts of the study area because of seasonal circulation of currents from south to north along the shore. The micro textural study of the heavy mineral grains from different locations in the study area revealed the mechanical and chemical erosions on the grain surfaces.

Response of M5 wheat (Triticum aestivum L.) mutant to low altitude growing condition

This study aims to study the adaptability of wheat mutant lines in the lowlands and determine the growth and production of the mutant lines. The research was conducted from September to December 2017 at Teaching Farm, Faculty of Agriculture, Hasanuddin University, Makassar, South Sulawesi Province. The study was carried out in the form of experiments arranged based on Randomized Block Design and further tested using orthogonal contrast. The treatments given were five M5 mutant genotypes and two convergent breeding genotypes. Three wheat varieties Dewata, Munal, and Selayar were used as comparisons. The results showed that the convergent breeding line (CB 145) showed good genetic traits on plant height parameters and the number of empty floret. Dewata, Munal, and Selayar varieties showed more average number of tillers (6.00 tillers) and 100 heavier grain weight (4.07 g) compared to the mutant genotypes. Dewata variety showed good genetic characteristics on panicle length parameter (6.50 cm) and grain weight per panicle (0.34 g). CB 169 genotype showed good genetic characteristics on the parameter number of grain per panicle which only produced the number of seeds per panicle (8.33 seeds).

MicroRNAs as potential targets for improving rice yield via plant architecture modulation: Recent studies and future perspectives

Ensuring agricultural food security is a major concern for the future world, and being the second most consumed crop, rice yield needs an urgent upliftment. Grain yield is a pleiotropic trait that employs a plethora of genes functioning in complex signalling cascades. The yield related genes are controlled by various regulatory factors including the microRNAs (miRNAs), the small 20-22 nucleotide (nt) non-coding RNAs, which have emerged as the master ribo-regulators of eukaryotic genes. Plant miRNAs can bind to highly complementary sequences in the target messenger RNAs (mRNAs) and negatively regulate gene expression to coordinate the various biological processes involved in plant development. In rice, an ideal plant architecture (IPA) has been regarded as the key to attain high yield and several miRNAs have been deciphered to play important roles in orchestrating vital regulatory procedures for achieving optimum plant morphological yield related traits like less unproductive tillers, more panicle branches and heavier grains. In this review, we present and discuss the various genetic engineering strategies undertaken to manipulate the miRNA-mRNA expression levels in order to achieve improved grain output by modulation of rice plant architecture and recent advances made in this regard.

Genetic and epistatic effects for grain quality and yield of three grain-size QTLs identified in brewing rice (Oryza sativa L.).

Rice (Oryza sativa L.) in Japan is not only a food staple but also an important material for the Japanese alcoholic beverage, sake. The grain used in sake brewing has different characters from the cooking rice grain, including a large grain size and high white-core expression rate (WCE). Because large-sized grains often have a heavy grain weight and higher yield, this trait is also important for cooking rice. Chalky grains, such as white-core or white-belly grains, are not ideal as cooking rice. Here, we report that three grain-size quantitative trait loci (QTLs; qGL4-2, qGWh5, qGWh10), derived from the brewing cultivar, Yamadanishiki, affect grain shape, chalky grain rate, and yield, using near isogenic and pyramiding lines in the genetic background of the cooking cultivar, Koshihikari. First, these QTLs influenced multiple components of grain shape, where epistatic effects were detected between qGL4-2 and qGWh5, for grain width and thickness, and between qGL4-2 and qGWh10, for grain length. Therefore, these QTLs may coordinate to control grain shape. Second, lines harboring qGWh5 or qGWh10 at the Yamadanishiki allele exhibited increased WCE, whereas lines with qGL4-2 and qGWh10 exhibited decreased white-belly grain rate (WBR). Thus, grain shape is associated with the occurrence of chalky grain, where the chalky type depends on the QTL. Finally, we used total panicle weight of plants as a simplified rice yield index, and a promising line pyramiding qGL4-2 and qGWh5 emerged. In conclusion, qGL4-2 would be useful for the breeding of cooking rice, to decrease WBR, while qGWh5 and qGWh10 were definitely more beneficial for that of brewing rice, to increase grain weight and WCE.

The factorial productivity components of peas with leafless and leafy morphotypes

The research work was carried out in the conditions of the southeast of the Voronezh region in the fields of the Research Institute of Agriculture of the Central-Blackearth area named after V. V. Dokuchaev in 2015-2017. The weather conditions during the years of the trial were quite favorable. The water and thermal regimes provided optimal conditions for the growth and development of pea plants, 1.3 in 2015, 1.2 in 2016 and 1.1 in 2017. The purpose of the study was to identify the factorial components that determine the productivity of peas belonging to different morphotypes. There were selected highly productive lines as objects of study. Before harvesting there was selected a material for analysis, and there were determined the following indicators: plant height, number of productive nodes, number of beans per plant, number of grains in a bean, number of grains per plant, 1000 grains weight, grain weight per plant. The grain productivity was determined after harvesting with a combine in terms of 14% moisture content. As a result of the analysis, there was found that the formation of grain productivity in peas of a leafy morphotype in comparison with a leafless morphotype was provided by a greater number of fruiting nodes: 3.31 and 2.53 pcs/plant. respectively (+0.78 pcs/plant); beans per plant: 5.27 and 4.19 pcs/plant. (+1.08 pcs/plant); and grains per plant: 18.6 and 17.5 pcs/plant (+1.1 pcs/plant). The productivity of the samples with a leafless morphotype was due to a larger number of grains per bean: 4.24 and 3.61 pieces/bean (+0.63 pieces/ bean) and heavier grains: 236 and 228 g (1000 grain weight +8 d). Differences in the trait “number of grains per plant” and “1000 grain weight” were within the experimental error.

Physical properties of parboiled milled local rice varieties marketed in South-East Nigeria.

Physical properties of rice grain is important for mechanisation and proper post-harvest handling operations to prevent post-harvest loss and achieve high head-rice grains. Knowledge on the physical properties of Nigeria's local rice is limited which has led to losses and production of low quality grains characterised by large amount of brokens and poor appearance. Physical properties of 18 local and 3 imported rice varieties (control), were evaluated using standard methods. The physical properties evaluated were grain dimensions, Arithmetic mean diameter, (AMD) geometric mean diameter (GMD), square mean diameter (SMD), sphericity, aspect ratio, surface area, general appearance, dockage and aroma. Most (77.78%) of the local rice varieties were long grain rice, 50% were slender grains and 50% were bold grains, 77.78% of the local rice varieties were heavy grains. The AMD, GMD and SMD of local rice grains ranged from 3.29-3.86mm, 8.02-10.36mm and 4.75-5.82mm, respectively. The sphericity, aspect ratio and surface area were in the range of 51.25-59.23%, 0.31-0.46 and 21.87-29.44mm2, respectively. A significant percentage (50%) of the local rice were grey coloured and unappealing in appearance. All the local rice varieties had dockage (5-70%) while the imported rice varieties had no dockage and possessed translucent light-cream to yellow shades and were appealing in appearance. These data are important for correct coupling and adjustment of post-harvest processing machine to prevent losses and produce high head-rice with appealing appearance.

Adaptability, stability, and agronomic performance of cowpea lines in Mato Grosso, Brazil

This work was carried out to evaluate adaptability and stability, agronomic performance, and phenotypic correlation between the characters of erect/semi-erect cowpea lines in Mato Grosso, Brazil. The trials were conducted in the municipalities of Nova Ubiratã-MT, Primavera do Leste-MT and Sinop-MT in 2014 and 2015. A total of 15 lines and five commercial controls were evaluated using a randomized complete block design (RBD) with four replications. Cultivation value, plant lodging, pod mass, pod length, number of grains per pod, grain mass, mass of 100 grains, grain index and grain yield were evaluated. Data were subjected to analysis of variance and yield adaptability and stability were estimated. Phenotypic correlations among characters were also estimated. The L22, L24, L25, L27, L31, L34 and L35 lines presented good performance for the evaluated characters and good yield adaptability and stability. Estimates of phenotypic correlations indicated that upright plants with smaller lodging presented smaller and lighter pods, with fewer grains per pod and heavier grains.

Multivariate Statistical and Multiproxy Constraints on Earthquake-Triggered Sediment Remobilization Processes in the Central Japan Trench.

Understanding the impact of earthquakes on subaqueous environments is key for submarine paleoseismological investigations seeking to provide long‐term records of past earthquakes. For this purpose, event deposits (e.g., turbidites) are, among others, identified and stratigraphically correlated over broad areas to test for synchronous occurrence of gravity flows. Hence, detailed spatiotemporal petrographic and geochemical fingerprints of such deposits are required to advance the knowledge about sediment source and the underlying remobilization processes induced by past earthquakes. In this study, we develop for the first time in paleoseismology a multivariate statistical approach using X‐ray fluorescence core scanning, magnetic susceptibility, and wet bulk density data that allow to test, confirm, and enhance the previous visual and lithostratigraphic correlation across two isolated basins in the central Japan Trench. The statistical correlation is further confirmed by petrographic heavy grain analysis of the turbidites and additionally combined with our novel erosion model based on previously reported bulk organic carbon 14C dates. We find surficial sediment remobilization, a process whereby strong seismic shaking remobilizes the uppermost few centimeters of surficial slope sediment, to be a predominant remobilization process, which partly initiates deeper sediment remobilization downslope during strong earthquakes at the Japan Trench. These findings shed new light on source‐to‐sink transport processes in hadal trenches during earthquakes and help to assess the completeness of the turbidite paleoseismic record. Our results further suggest that shallow‐buried tephra on the slope might significantly influence sediment remobilization and the geochemical and petrographic fingerprints of the resulting event deposits.

Control of Grain Size and Weight by the GSK2-LARGE1/OML4 Pathway in Rice.

Regulation of grain size is crucial for improving crop yield and is also a basic aspect in developmental biology. However, the genetic and molecular mechanisms underlying grain size control in crops remain largely unknown despite their central importance. Here, we report that the MEI2-LIKE PROTEIN4 (OML4) encoded by the LARGE1 gene is phosphorylated by GLYCOGEN SYNTHASE KINASE2 (GSK2) and negatively controls grain size and weight in rice (Oryza sativa). Loss of function of OML4 leads to large and heavy grains, while overexpression of OML4 causes small and light grains. OML4 regulates grain size by restricting cell expansion in the spikelet hull. OML4 is expressed in developing panicles and grains, and the GFP-OML4 fusion protein is localized in the nuclei. Biochemical analyses show that the GSK2 physically interacts with OML4 and phosphorylates it, thereby possibly influencing the stability of OML4. Genetic analyses support that GSK2 and OML4 act, at least in part, in a common pathway to control grain size in rice. These results reveal the genetic and molecular mechanism of a GSK2-OML4 regulatory module in grain size control, suggesting that this pathway is a suitable target for improving seed size and weight in crops.

Gene action that controlling some characters on F2 generation derived from the crossing of Silopuk red rice with Fatmawati superior variety

An F2 population is a segregated population where recombinant characters emergence. To selection these recombinant characters, it is important to know their genetic parameters. The purpose of this study was to determine the action of genes controlling the number of productive tillers, the total number of grains per panicle, the percentage of grain-filled per panicle, weight of one thousand filled grains and total grain weight per hill of F2 generations. Silopuk cultivar with red rice characteristic but has weakness such as long harvest age, high plants, and medium grain size, while superior Fatmawati has early maturity, semidwarf plant n thickness, big grain size, and white grain color. The character can be improved by the plant breeding method using hybridization. The research method used is the experimental method without replication with the head to row method [clump to row] and analyzed using the analysis of Skewness and Kurtosis. The result of the crossing of these varieties is expected to obtain large and heavy grain size, early age as Fatmawati and red rice as Silopuk. Z skewness test results and Z test kurtosis on F tow generation for all characters observed are controlled by many additive genes. The characters that have additive gene action such as plant height, panicle length and total grain size can be used as selection criteria for generation F three.

Exploration Potential of Fine-Fraction Heavy Mineral Concentrates from Till Using Automated Mineralogy: A Case Study from the Izok Lake Cu–Zn–Pb–Ag VMS Deposit, Nunavut, Canada

Exploration under thick glacial sediment cover is an important facet of modern mineral exploration in Canada and northern Europe. Till heavy mineral concentrate (HMC) indicator mineral methods are well established in exploration for diamonds, gold, and base metals in glaciated terrain. Traditional methods rely on visual examination of >250 µm HMC material, however this study applies modern automated mineralogical methods (mineral liberation analysis (MLA)) to investigate the finer (<250 µm) fraction of till HMC. Automated mineralogy of finer material allows for rapid collection of precise compositional and morphological data from a large number (10,000–100,000) of heavy mineral grains in a single sample. The Izok Lake volcanogenic massive sulfide (VMS) deposit, one of the largest undeveloped Zn–Cu resources in North America, has a well-documented fan-shaped indicator mineral dispersal train and was used as a test site for this study. Axinite, a VMS indicator mineral difficult to identify optically in HMC, is identified in till samples up to 8 km down ice. Epidote and Fe-oxide minerals are identified, with concentrations peaking proximal to mineralization. Corundum and gahnite are intergrown in till samples immediately down ice of mineralization. Till samples also contain chalcopyrite and galena up to 8 km down ice of mineralization, an increase from 1.3 km for sulfide minerals in till previously reported for coarse HMC fractions. Some of these sulfide grains occur as inclusions within chemically and physically robust mineral grains and would not be identified visually in the coarse HMC visual counts. Best practices for epoxy mineral grain mounting and abundance reporting are presented along with the automated mineralogy of till samples down ice of the deposit.

Common gardens in teosintes reveal the establishment of a syndrome of adaptation to altitude.

In plants, local adaptation across species range is frequent. Yet, much has to be discovered on its environmental drivers, the underlying functional traits and their molecular determinants. Genome scans are popular to uncover outlier loci potentially involved in the genetic architecture of local adaptation, however links between outliers and phenotypic variation are rarely addressed. Here we focused on adaptation of teosinte populations along two elevation gradients in Mexico that display continuous environmental changes at a short geographical scale. We used two common gardens, and phenotyped 18 traits in 1664 plants from 11 populations of annual teosintes. In parallel, we genotyped these plants for 38 microsatellite markers as well as for 171 outlier single nucleotide polymorphisms (SNPs) that displayed excess of allele differentiation between pairs of lowland and highland populations and/or correlation with environmental variables. Our results revealed that phenotypic differentiation at 10 out of the 18 traits was driven by local selection. Trait covariation along the elevation gradient indicated that adaptation to altitude results from the assembly of multiple co-adapted traits into a complex syndrome: as elevation increases, plants flower earlier, produce less tillers, display lower stomata density and carry larger, longer and heavier grains. The proportion of outlier SNPs associating with phenotypic variation, however, largely depended on whether we considered a neutral structure with 5 genetic groups (73.7%) or 11 populations (13.5%), indicating that population stratification greatly affected our results. Finally, chromosomal inversions were enriched for both SNPs whose allele frequencies shifted along elevation as well as phenotypically-associated SNPs. Altogether, our results are consistent with the establishment of an altitudinal syndrome promoted by local selective forces in teosinte populations in spite of detectable gene flow. Because elevation mimics climate change through space, SNPs that we found underlying phenotypic variation at adaptive traits may be relevant for future maize breeding.

Quantum effects in bi-dust plasmas

In this paper a theoretical approach has been carried out using a fluid model on a bi-dust plasma which consist of two dusts negative charged different particles in an electron–ion plasma. In such system, this fluid model describe a dense strong coupled heavy dust grain together with a weak coupled light dusty particle. The bulk is immersed in a system of electrons and ions dominated by a Thomas–Fermi density distribution, where interaction and propagation of solitary dust acoustic solitary waves will be analyzed. This investigation will be carried out for arbitrary amplitude of solitary dust acoustic waves. These are originated through the presence of both dust grains in the plasma system. Therefore, it is used a set of fluid equation which determine general expressions for the concentrations of different dust particles. The onset of the Sagdeev method is then employed in order to look for influence of the light component on the quantum system. In this way there is an increasing or decreasing in the Sagdeev potential. This is a quantum effect phenomena.