Resolution enhancement for drill-core hyperspectral mineral mapping

Drill-core samples are a key component in mineral exploration campaigns, and their rapid and objective analysis is becoming increasingly important. Hyperspectral imaging of drill-cores is a non-destructive technique that allows for non-invasive and fast mapping of mineral phases and alteration patterns. The use of adapted machine learning techniques such as supervised learning algorithms allows for a robust and accurate analysis of drill-core hyperspectral data. One of the remaining challenge is the spatial sampling of hyperspectral sensors in operational conditions, which does not allow us to render the textural and mineral diversity that is required to map minerals with low abundances and fine structures such as veins and faults. In this work, we propose a methodology in which we implement a resolution enhancement technique, a coupled non-negative matrix factorization, using hyperspectral, RGB images and high-resolution mineralogical data to produce mineral maps at higher spatial resolutions and to improve the mapping of minerals. The results demonstrate that the enhanced maps not only provide better details in the alteration patterns such as veins but also allow for mapping minerals that were previously hidden in the hyperspectral data due to its low spatial sampling

Modified protocol of harvesting, extraction, and normalization approaches for gas chromatography mass spectrometry-based metabolomics analysis of adherent cells grown under high fetal calf serum conditions

A gas chromatography mass spectrometry (GC-MS) metabolomics protocol was modified for quenching, harvesting, and extraction of metabolites from adherent cells grown under high (20%) fetal calf serum conditions. The reproducibility of using either 50% or 80% methanol for quenching of cells was compared for sample harvest. To investigate the efficiency and reproducibility of intracellular metabolite extraction, different volumes and ratios of chloroform were tested. Additionally, we compared the use of total protein amount versus cell mass as normalization parameters. We demonstrate that the method involving 50% methanol as quenching buffer followed by an extraction step using an equal ratio of methanol:chloroform:water (1:1:1, v/v/v) followed by the collection of 6 mL polar phase for GC-MS measurement was superior to the other methods tested. Especially for large sample sets, its comparative ease of measurement leads us to recommend normalization to protein amount for the investigation of intracellular metabolites of adherent human cells grown under high (or standard) fetal calf serum conditions. To avoid bias, care should be taken beforehand to ensure that the ratio of total protein to cell number are consistent among the groups tested. For this reason, it may not be suitable where culture conditions or cell types have very different protein outputs (e.g., hypoxia vs. normoxia). The full modified protocol is available in the Supplementary Materials

Coronal heating in coupled photosphere-chromosphere-coronal systems: turbulence and leakage

Coronal loops act as resonant cavities for low frequency fluctuations that are transmitted from the deeper layers of the solar atmosphere and are amplified in the corona, triggering nonlinear interactions. However trapping is not perfect, some energy leaks down to the chromosphere, thus limiting the turbulence development and the associated heating. We consider the combined effects of turbulence and leakage in determining the energy level and associated heating rate in models of coronal loops which include the chromosphere and transition region. We use a piece-wise constant model for the Alfven speed and a Reduced MHD - Shell model to describe the interplay between turbulent dynamics in the direction perpendicular to the mean field and propagation along the field. Turbulence is sustained by incoming fluctuations which are equivalent, in the line-tied case, to forcing by the photospheric shear flows. While varying the turbulence strength, we compare systematically the average coronal energy level (E) and dissipation rate (D) in three models with increasing complexity: the classical closed model, the semi-open corona model, and the corona-chromosphere (or 3-layer) model, the latter two models allowing energy leakage. We find that: (i) Leakage always plays a role (even for strong turbulence), E and D are systematically lower than in the line-tied model. (ii) E is close to the resonant prediction, i.e., assuming effective turbulent correlation time longer than the Alfven coronal crossing time (Ta). (iii) D is close to the value given by the ratio of photospheric energy divided by Ta (iv) The coronal spectra exibits an inertial range with 5/3 spectral slope, and a large scale peak of trapped resonant modes that inhibit nonlinear couplings. (v) In the realistic 3-layer model, the two-component spectrum leads to a damping time equal to the Kolmogorov time reduced by a factor u_rms/Va_coronaComment: 15 pages, 15 figures, Accepted for publication in A&

Investigation of Parietal Polysaccharides from Retama raetam Roots

This study characterizes the cell wall hemicellulose and pectins polymers of Retama raetam. This species develops a particularly important root system and is adapted to arid areas. The cellulose, hemicelluloses and pectins were extracted. The cellulose remains the major component of the wall (27% for young roots and 80% for  adult roots), hemicelluloses (14.3% for young roots and 3.6%  for adult roots) and pectins (17.3% for young roots and 4.1% for adult roots). The monosaccharidic composition of water soluble extracts determined by gas liquid chromatography (GLC) and completed by infrared (FTIR) spectroscopy of hemicellulosic shows the presence of xylose as a major monosaccharide in the non-cellulose polysaccharides (47.8% for young roots and 59.5% for adult roots). These results indicate the presence of the homogalacturonans and rhamnogalacturonans in pectin. This study constitutes the preliminary data obtained in the biochemical analysis of the parietal compounds of the roots of a species which grows in an arid area in comparison with those of its aerial parts.Keywords: Retama raetam, Roots, Cell Wall, Investigation, Polysaccharides, Monosaccharidi

Progression-dependent altered metabolism in osteosarcoma resulting in different nutrient source dependencies

Osteosarcoma (OS) is a primary malignant bone tumor and OS metastases are mostly found in the lung. The limited understanding of the biology of metastatic processes in OS limits the ability for effective treatment. Alterations to the metabolome and its transformation during metastasis aids the understanding of the mechanism and provides information on treatment and prognosis. The current study intended to identify metabolic alterations during OS progression by using a targeted gas chromatography mass spectrometry approach. Using a female OS cell line model, malignant and metastatic cells increased their energy metabolism compared to benign OS cells. The metastatic cell line showed a faster metabolic flux compared to the malignant cell line, leading to reduced metabolite pools. However, inhibiting both glycolysis and glutaminolysis resulted in a reduced proliferation. In contrast, malignant but non-metastatic OS cells showed a resistance to glycolytic inhibition but a strong dependency on glutamine as an energy source. Our in vivo metabolic approach hinted at a potential sex-dependent metabolic alteration in OS patients with lung metastases (LM), although this will require validation with larger sample sizes. In line with the in vitro results, we found that female LM patients showed a decreased central carbon metabolism compared to metastases from male patients

Influence of the definition of dissipative events on their statistics

A convenient and widely used way to study the turbulent plasma in the solar corona is to do statistics of properties of events (or structures), associated with flares, that can be found in observations or in numerical simulations. Numerous papers have followed such a methodology, using different definitions of an event, but the reasons behind the choice of a particular definition (and not another one) is very rarely discussed. We give here a comprehensive set of possible event definitions starting from a one-dimensional data set such as a time-series of energy dissipation. Each definition is then applied to a time-series of energy dissipation issued from simulations of a shell-model of magnetohydrodynamic turbulence as defined in Giuliani and Carbone (1998), or from a new model of coupled shell-models designed to represent a magnetic loop in the solar corona. We obtain distributions of the peak dissipation power, total energy, duration and waiting-time associated to each definition. These distributions are then investigated and compared, and the influence of the definition of an event on statistics is discussed. In particular, power-law distributions are more likely to appear when using a threshold. The sensitivity of the distributions to the definition of an event seems also to be weaker for events found in a highly intermittent time series. Some implications on statistical results obtained from observations are discussed.Comment: 8 pages, 13 figures. Submitted to Astronomy&Astrophysic

Transition State Spectroscopy of the Photoinduced Ca + CH3F Reaction. 2. Experimental and Ab Initio Studies of the Free Ca***FCH3 Complex

International audienceThe Ca* + CH3F CaF* + CH3 reaction was photoinduced in 1:1 Ca***CH3F complexes formed in a supersonic expansion. The transition state of the reaction was explored by monitoring the electronically excited product, CaF, while scanning the laser that turns on the reaction. Moreover, the electronic structure of the Ca***FCH3 system was studied using ab initio methods by associating a pseudopotential description of the [Ca2+] and [F7+] cores, a core polarization operator on calcium, an extensive Gaussian basis and a treatment of the electronic problem at the CCSD(T) (ground state) and RSPT2 (excited states) level. In this contribution we present experimental results for the free complex and a comparison with the results of a previous experiment where the Ca***CH3F complexes are deposited at the surface of large argon clusters. The ab initio calculations allowed an interpretation of the experimental data in terms of two reaction mechanisms, one involving a partial charge transfer state, the other involving the excitation of the C-F stretch in the CH3F moiety prior to charge transfer

Дискурсивна стратегія як когнітивно-комунікативний феномен

Статья из специализированного выпуска научного журнала "Культура народов Причерноморья", материалы которого объединены общей темой "Язык и Мир" и посвящены общим вопросам Языкознания и приурочены к 80-летию со дня рождения Николая Александровича Рудякова.Стаття із спеціалізованого випуску наукового журналу "Культура народов Причерноморья", матеріали якого поєднані загальною темою "Мова і Світ" і присвячені загальним питанням мовознавства і приурочені до 80-річчя з дня народження Миколи Олександровича Рудякова