702 research outputs found
Cryopreservation of Byrsonima intermedia embryos followed by room temperature thawing
Byrsonima intermedia is a shrub from the Brazilian Cerrado with medicinal properties. The storage of biological material at ultra-low temperatures (-196°C) is termed cryopreservation and represents a promising technique for preserving plant diversity. Thawing is a crucial step that follows cryopreservation. The aim of this work was to cryopreserve B. intermedia zygotic embryos and subsequently thaw them at room temperature in a solution rich in sucrose. The embryos were decontaminated and desiccated in a laminar airflow hood for 0-4 hours prior to plunging into liquid nitrogen. The embryo moisture content (% MC) during dehydration was assessed. Cryopreserved embryos were thawed in a solution rich in sucrose at room temperature, inoculated in a germination medium and maintained in a growth chamber. After 30 days, the embryo germination was evaluated. No significant differences were observed between the different embryo dehydration times, where they were dehydrated for at least one hour. Embryos with a MC between 34.3 and 20.3% were germinated after cryopreservation. In the absence of dehydration, all embryos died following cryopreservation. We conclude that B. intermedia zygotic embryos can be successfully cryopreserved and thawed at room temperature after at least one hour of dehydration in a laminar airflow bench
Distribution and contamination status of heavy metals in estuarine sediments near Cua Ong Harbour, Ha Long Bay, Vietnam
The distribution, controlling geochemical factors and contamination status of heavy metals in estuarine sediments near Cua Ong Habor, Ha Long Bay (Vietnam) were investigated. 36 surface sediment samples were collected and analyzed for major elements (Al, Ca, Fe, K, Mg, S), heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn), organic matter, loss on ignition (LOI), grain size composition and pH. Spatial distribution patterns of heavy metals as well as their controlling factors were elucidated based on geochemical mapping and statistical methods such as the Pearson ProductMoment linear correlation and Factor Analysis. The results illustrated that the distribution patterns of As, Cd, Cr, Cu, Ni, Pb and Zn are mainly controlled by organic matter and clay minerals and determined by the distribution of the finegrained fraction (F < 63 µm) in the sediments. In contrast, Fe and Mn compounds seem to exert some control on the distribution of Co. Carbonates partly control the distribution of Mn, but are not important with respect to the other studied heavy metals. The contamination status by heavy metals was assessed based on comparison with Canadian, Wisconsin- United States and Flemish numerical Sediment Quality Guidelines, and calculation of Geo-accumulation Index (Igeo) and Enrichment Factor (EF). The results indicated that natural processes such as weathering and erosion of bedrock are the main supply sources of heavy metals in sediments near Cua Ong Harbor. Among the studied heavy metals, only As is of concern whereas Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn seem to reflect their background concentrations in sediments of Ha Long Bay
Determinants of soil organic matter chemistry in maritime temperate forest ecosystems
While the influence of climate, vegetation, management and abiotic site factors on total carbon budgets and turn-over is intensively assessed, the influences of these ecosystem properties on the chemical complexity of soil organic matter (SOM) remains poorly understood. This study addresses the chemical composition of NaOH-extracted SOM from maritime temperate forest sites in Flanders (Belgium) by pyrolysis-GC/MS. The studied forests were chosen based on dominant tree species (Pinus sylvestris, Fagus sylvatica, Quercus robur and Populus spp.), soil texture and soil-moisture conditions. Differences in extractable-SOM pyrolysis products were correlated to site variables including dominant tree species, management of the woody biomass, site history, soil properties, total carbon stocks and indicators for microbial activity. Despite of a typical high intercorrelation between these site variables, the influence of the dominant tree species is prominent. The extractable-SOM composition is strongly correlated to litter quality and available nutrients. In nutrient-poor forests with low litter quality, the decomposition of relatively recalcitrant compounds (i.e. short and mid-chain alkanes/alkenes and aromatic compounds) appears hampered, causing a relative accumulation of these compounds in the soil. However, if substrate quality is favorable, no accumulations of recalcitrant compounds were observed, not even under high soil-moisture conditions. Former heathland vegetation still had a profound influence on extractable-SOM chemistry of young pine forests after a minimum of 60 year
A new approach to geobarometry by combining fluid inclusion and clumped isotope thermometry in hydrothermal carbonates
This study presents a new approach to geobarometry by combining fluid inclusion and clumped isotope (\u39447) thermometry on carbonate minerals. The offset between homogenisation temperatures of primary fluid inclusions with known composition and \u39447 temperatures of the host mineral allows a direct estimation of the fluid pressure at the time of carbonate crystallisation. This new approach is illustrated via hydrothermal dolomite samples from the Variscan foreland fold-and-thrust belt in northern Spain. Clumped isotope analyses yield crystallisation temperatures (107\u2013168\ub0C) which are higher than homogenisation temperatures in corresponding samples (95\u2013145\ub0C). The calculated pressure values suggest that dolomitizing fluids were overpressured during formation of zebra dolomite textures, whereas lower pressures are obtained for dolomite cement from breccia textures. This new approach to geobarometry opens up the possibility of estimating the pressure of carbonate crystallisation and has potential applications in diagenesis, basin analysis, ore geology and tectonics
Precursor and ambient rock paleothermometry to assess the thermicity of burial dolomitization in the southern Cantabrian Zone (northern Spain)
International audiencePaleozoic rocks in the Cantabrian Zone, and the Variscan foreland fold-and-thrust belt on the Iberian Peninsula have been affected by a sequence of diagenetic to epizonal thermal events. Late- to Post-Variscan hot fluid circulation caused a large-scale burial dolomitization and ore mineralization, mostly in Cambrian and a Lower to Middle Carboniferous carbonate sucessions. The goal of this study is to analyze and compare the temperatures experienced by the carbonate precursor rocks, as well as the under- and over-lying siliciclastic ambient rocks to gain a better understanding of the thermicity of dolomitization. These temperatures are evaluated based on published paleothermal datasets combined with new data obtained from Rock–Eval pyrolysis and vitrinite reflectance analysis of Carboniferous rocks rich in organic matter. The overall results indicate that reworking of detrital sediments in synorogenic ambient siliciclastics results in an anomalously high thermal maturity recorded by bulk rock techniques such as illite crystallinity and Rock–Eval pyrolysis. In situ VR-derived paleotemperatures recorded by ambient siliciclastic rocks appear to be higher compared to CAI-derived temperatures for carbonate precursor rocks. This variation in thermal maturity is likely related to the analytical techniques used to obtain CAI and VR data, and the empirical equations applied to calculate corresponding paleotemperatures. Conodont fragments were not as sensitive compared to vitrinite, and the color alteration process could have suffered from hydrothermal alteration. A secondary cause might be a different response to mechanical deformation between siliciclastic and carbonate units during the Variscan and post-Variscan geodynamic evolution of the study area. Rigid precursor carbonate units experienced fluid circulation mainly along distinct and spaced fracture zones, creating fracture-related dolomite geobodies and ore mineralization. Soft ambient siliciclastic rocks experienced more diffuse fluid circulation and heat dissipation. The different paleothermometry datasets compiled for the study area indicate that the fluids circulating during Late- to Post-Variscan times, with associated fracture-related dolomitization and ore mineralization in carbonate precursors, are hydrothermal. The highest paleotemperatures were recorded in ambient and precursor rocks in the highly tectonized northern part of the study area, where several thrusts and faults allowed intense fluid circulation. Positive temperature anomalies within the precursor carbonates correlate well with the occurrence of dolomite geobodies and ore mineral deposits. Such anomalies could thus be used as an exploration tool for hydrothermal dolomite bodies in analog sub-surface settings
The Potential Of High-Resolution BAC-FISH In Banana Breeding
Abstract The genetic complexity in the genus Musa has been subject of study in many breeding programs worldwide. Parthenocarpy, female sterility, polyploidy in different cultivars and limited amount of genetic and genomic information make the production of new banana cultivars difficult and time consuming. In addition, it is known that part of the cultivars and related wild species in the genus contain numerous chromosomal rearrangements. In order to produce new cultivars more effectively breeders must better understand the genetic differences of the potential crossing parents for introgression hybridization, but extensive genetic information is lacking. As an alternative to achieve information on genetic collinearity we make use of modern chromosome map technology known as high-resolution fluorescent in situ hybridization (FISH). This article presents the technical aspects and applications of such a technology in Musa species. The technique deals with BAC clone positioning on pachytene chromosomes of Calcutta 4 (Musa acuminata ssp. burmanicoides, A genome group, section Eumusa) and M. velutina (section Rodochlamys). Pollen mother cells digestion with pectolytic enzymes and maceration with acetic acid were optimized for making cell spread preparations appropriate for FISH. As an example of this approach we chose BAC clones that contain markers to known resistance genes and hybridize them for establishing their relative positions on the two species. Technical challenges for adapting existing protocols to the banana cells are presented. We also discuss how this technique can be instrumental for validating collinearity between potential crossing parents and how the method can be helpful in future mapping initiatives, and how this method allows identification of chromosomal rearrangements between related Musa species and cultivar
Integrated geophysical and petrological study of fluid expulsion features along the Moroccan Atlantic margin
In this study we integrate a geophysical – carbonate petrological data set, collected during the TTR-14 cruise (summer 2004) along the Moroccan Atlantic margin in Gulf of Cadiz (Southern area, 400m – 1000m and El Arraiche mud volcano field). This allows us to investigate the deeper structure and its control on fluid venting, to address the nature of seafloor topographical features, fluid geochemistry and venting processes. The deeper structure of the Southern area is dominated by two NW trending anticlinal acoustic basement ridges. Their northern flank and top is cut by major present-day active, normal faults, along which four dome structures and the Meknes mud volcano (mv), are concentrated. These ridges correspond to rotated, faultbounded blocks breaking up the top of the accretionary wedge. This indicates the southward prolongation of extensional tectonics and its structural control on mud volcanism, south of the El Arraiche field, which is also evidenced by the typical sandstone mud breccias recovered at the Meknes mv. Carbonate cemented mud breccia from the Meknes (type M) and the Kidd (type K) mv, and cemented sediment portions from Pen Duick Escarpment (type PD), all possess similar carbon isotopic (-19 to -29%¸ VPDB) and carbonate geochemical signatures, indicating seepage of a geochemical similar thermogenic hydrocarbon-bearing fluid source. Slightly elevated d18O values of HMC-cemented type M crusts suggest the former presence and dissociation of gas hydrates. The brecciated fabric, intraclasts and aragonite cement morphology, typical of type K crusts testify of a relative vigorous fluid ascent. HMC-calcian dolomite cemented PD crusts were likely formed under conditions of slower fluid ascent. Their actual near-seafloor occurrence, well above the base of the SRZ, is hypothesized to relate to erosion and migration of the SRZ by variations in upward hydrocarbon fluxes
The shortwave infrared bands response to stomatal conductance in Conference" Pear Trees (Pyrus communis L.)"
Published: 8 October 201
Nasal Morphology of the Chinese: Three-Dimensional Reference Values for Rhinoplasty
OBJECTIVE: To determine normative nasal measurements for Chinese young adults, conditioned on demographics.
STUDY DESIGN: A cross-sectional descriptive study.
SETTING: A university hospital.
SUBJECTS AND METHODS: Three-dimensional (3D) photographs were captured from 103 Chinese subjects between 18 and 35 years of age using a commercial stereophotographic system. Anthropometric landmarks were identified on these 3D surface images, and measurements suitable for nasal analysis were performed and contrasted against established Caucasian norms. Gender differences in anthropometric dimensions were also analyzed.
RESULTS: Normative data for these measurements are made available. Linear nasal measurements, except those for mid-columella length, were significantly larger in men than in women; further, the nasal tip angle and nasofrontal angle were significantly larger in Chinese women. Contrasts of these new data against published Caucasian norms revealed dimensions that differ for these 2 groups. The Chinese normative mean values for morphological nose width, nasal tip angle, nasofrontal angle, and alar slope angle exceeded those reported for North American Caucasians.
CONCLUSIONS: Gender-specific normative data for the Chinese nose were established in this study to provide a useful tool for surgeons in dealing with rhinoplasty. Moreover, the Chinese nasal anthropometric measurements in this study are broader and flatter than those reported for North American Caucasians.
© American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.postprin
Lattice Boltzmann simulations of fluid flow in continental carbonate reservoir rocks and in upscaled rock models generated with multiple-point geostatistics
Microcomputed tomography (mu CT) and Lattice Boltzmann Method (LBM) simulations were applied to continental carbonates to quantify fluid flow. Fluid flow characteristics in these complex carbonates with multiscale pore networks are unique and the applied method allows studying their heterogeneity and anisotropy. 3D pore network models were introduced to single-phase flow simulations in Palabos, a software tool for particle-based modelling of classic computational fluid dynamics. In addition, permeability simulations were also performed on rock models generated with multiple-point geostatistics (MPS). This allowed assessing the applicability of MPS in upscaling high-resolution porosity patterns into large rock models that exceed the volume limitations of the mu CT. Porosity and tortuosity control fluid flow in these porous media. Micro-and mesopores influence flow properties at larger scales in continental carbonates. Upscaling with MPS is therefore necessary to overcome volume-resolution problems of CT scanning equipment. The presented LBM-MPS workflow is applicable to other lithologies, comprising different pore types, shapes, and pore networks altogether. The lack of straightforward porosity-permeability relationships in complex carbonates highlights the necessity for a 3D approach. 3D fluid flow studies provide the best understanding of flow through porous media, which is of crucial importance in reservoir modelling
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