ENVIRONMENTAL IMPACT OF SEISMIC RESEARCH WORKS FOR OIL AND GAS DEPOSITS IN THE BLACK SEA

Environmental impact of seismic research works for oil and gas deposits in the Black Sea. The prospecting and exploitation activity of hydrocarbon deposits in Romania has experienced a major development in the nineteenth century and has remained since a major component in achieving energy independence in our country. In 1970 the oil and gas production in Romania reached a peak of over 14.5 million tons of crude oil. Gas production reached 33 million tons of oil equivalents. After 1990 the production level fell again, because of the depletion of the existing resources and the lack of investment prevented the discovery and the development of new fields. They have led in the last few years to a decrease of the oil production level to less than 5.0 million tons of oil and of the gas production of 10,3 million oil equivalent. After 1990 the Romanian Government through THE NATIONAL AGENCY FOR MINERAL RESOURCES has decided to organize international auctions to award a series of contracts regarding exploration and participation to rates of production of specialized companies that run all the financial funds and necessary technologies for the development of hydrocarbon prospecting activities. That is why in the Black Sea, beside the oil and gas deposits leased to OMV Petrom, there were also leased 7 areas needed for research, exploration and possible exploitation of oil and gas deposits. This paper presents the effects of seismic research works on the environment, considering that these are the first that will run on the platform of the Black Sea shore

Rotationally-invariant mapping of scalar and orientational metrics of neuronal microstructure with diffusion MRI

We develop a general analytical and numerical framework for estimating intra- and extra-neurite water fractions and diffusion coefficients, as well as neurite orientational dispersion, in each imaging voxel. By employing a set of rotational invariants and their expansion in the powers of diffusion weighting, we analytically uncover the nontrivial topology of the parameter estimation landscape, showing that multiple branches of parameters describe the measurement almost equally well, with only one of them corresponding to the biophysical reality. A comprehensive acquisition shows that the branch choice varies across the brain. Our framework reveals hidden degeneracies in MRI parameter estimation for neuronal tissue, provides microstructural and orientational maps in the whole brain without constraints or priors, and connects modern biophysical modeling with clinical MRI.Comment: 25 pages, 12 figures, elsarticle two-colum

ARBORELE GENEALOGIC AL APARIȚIEI, DEZVOLTĂRII ȘI REGLEMENTĂRII PRINCIPIILOR DREPTULUI ELECTORAL ÎN REPUBLICA MOLDOVA

În prezentul articol este abordată și explicată problema genezei arborelui genealogic al apariției, dezvoltării și reglementării principiilor dreptului electoral în Republica Moldova. În acest scop, s-a recurs la genealogie pentru a vedea dacă în cadrul ei au fost tratate sau nu aceste principii. Drept urmare, am constatat că în cadrul ei nu au fost abordate apariția, dezvoltarea și reglementarea principiilor dreptului electoral, în particular, în Republica Moldova sau în alte state. Totuși, credem că ideea despre evoluție, geneză, scopul studiului, metodele, uneltele, materialele folosite etc. este binevenită și că, după analogie, ea poate fi aplicată la cercetarea apariției, dezvoltării și reglementarii principiilor dreptului electoral în Republica Moldova

Intra- and extra-axonal axial diffusivities in the white matter: which one is faster?

A two-compartment model of diffusion in white matter, which accounts for intra- and extra-axonal spaces, is associated with two plausible mathematical scenarios: either the intra-axonal axial diffusivity is higher than the extra-axonal (Branch 1), or the opposite (Branch 2). This duality calls for an independent validation of compartment axial diffusivities, to determine which of the two cases holds. The aim of the present study was to use an intracerebroventricular injection of a gadolinium-based contrast agent to selectively reduce the extracellular water signal in the rat brain, and compare diffusion metrics in the genu of the corpus callosum before and after gadolinium infusion. The diffusion metrics considered were diffusion and kurtosis tensor metrics, as well as compartment-specific estimates of the WMTI-Watson two-compartment model. A strong decrease in genu T1 and T2 relaxation times post-Gd was observed (p < 0.001), as well as an increase of 48% in radial kurtosis (p < 0.05), which implies that the relative fraction of extracellular water signal was selectively decreased. This was further supported by a significant increase in intra-axonal water fraction as estimated from the two-compartment model, for both branches (p < 0.01 for Branch 1, p < 0.05 for Branch 2). However, pre-Gd estimates of axon dispersion in Branch 1 agreed better with literature than those of Branch 2. Furthermore, comparison of post-Gd changes in diffusivity and dispersion between data and simulations further supported Branch 1 as the biologically plausible solution, i.e. the intra-axonal axial diffusivity is higher than the extra-axonal one. This result is fully consistent with other recent measurements of compartment axial diffusivities that used entirely different approaches, such as diffusion tensor encoding

CERCETAREA PSIHOLOGICĂ A INTERESULUI ELECTORAL LA VÂRSTA TINEREȚII

În acest articol este analizată problema absenteismului electoral în rândul tinerilor din cadrul ultimelor alegeri pre­zidențiale, care s-au desfășurat  în toamna anului 2016, prin prisma secționării perioadei tinereții, raportată la criteriul gender (bărbați/femei), habitat (rural/urban) și votul din diaspora, precum și necesitatea abordării subiectului respectiv din perspectiva psihologică. Este examinată problema întocmirii unor tehnici adecvate de cercetare experimentală a inter­esului electoral la vârsta tinereții.THE PSYCHOLOGICAL RESEARCH OF THE ELECTORAL INTEREST OF YOUNG PEOPLEThis article analyzes the problem of youth absenteeism in the last presidential election, which took place in the autumn of 2016, through the segmentation of the youth period, based on gender (male/female), rural (urban) habitat, and the diaspora vote, and the need to address the subject from a psychological perspective. The issue of developing appropriate experimental research techniques of electoral interest at the age of youth is examined.</p

MP-PCA denoising for diffusion MRS data: promises and pitfalls

Diffusion-weighted (DW) magnetic resonance spectroscopy (MRS) suffers from a lower signal to noise ratio (SNR) compared to conventional MRS owing to the addition of diffusion attenuation. This technique can therefore strongly benefit from noise reduction strategies. In the present work, the Marchenko-Pastur principal component analysis (MP-PCA) denoising is tested on Monte Carlo simulations and on in vivo DW-MRS data acquired at 9.4T in the rat brain. We provide a descriptive study of the effects observed following different MP-PCA denoising strategies (denoising the entire matrix versus using a sliding window), in terms of apparent SNR, rank selection, noise correlation within and across b-values and quantification of metabolite concentrations and fitted diffusion coefficients. MP-PCA denoising yielded an increased apparent SNR, a more accurate B0 drift correction between shots, and similar estimates of metabolite concentrations and diffusivities compared to the raw data. No spectral residuals on individual shots were observed but correlations in the noise level across shells were introduced, an effect which was mitigated using a sliding window, but which should be carefully considered.Comment: Cristina Cudalbu and Ileana O. Jelescu have contributed equally to this manuscrip

LEGAL REGULATION OF THE PRINCIPLES TOTALIZATION AND VERIFICATION OF VOTING RESULTS

The objectives of the study: to research the electoral process; to establish the stages of this complex system; to highlight its essential characteristics; to determine the category of principles of the final stage of the electoral process; to elucidate the essence of the possible principles of aggregating and verifying the results of voting; present and substantiate the content of each of these principles. The research methods used were analysis and synthesis, abstraction and generalization, classification and concretization, affirmation and denial, deduction and induction, etc. The results of the paper: we determined, characterized and demonstrated the following principles of totalization and verification of voting results: the principle of the integrity of the procedure counting of votes; the principle of accurate recording of election results; the principle of the integrity of the procedure for centralizing election results; the principle of parallel counting of votes; the principle of truthfully calculating the results of electronic voting; the principle of correctly announcing election results; the principle of timely publication of official results; the principle of verifying the election results; the principle of confirmation of election results; the conditions for implementing the electoral principles. The basis for this order and classification of the principles of totalization and verification of voting results was the content and sequence of sub-stages of the final stage of the elections. In this order, we have presented and substantiated the content of each of these principles

MP-PCA denoising for diffusion MRS data: promises and pitfalls.

Diffusion-weighted (DW) magnetic resonance spectroscopy (MRS) suffers from a lower signal to noise ratio (SNR) compared to conventional MRS owing to the addition of diffusion attenuation. This technique can therefore strongly benefit from noise reduction strategies. In the present work, Marchenko-Pastur principal component analysis (MP-PCA) denoising is tested on Monte Carlo simulations and on in vivo DW-MRS data acquired at 9.4T in rat brain and at 3T in human brain. We provide a descriptive study of the effects observed following different MP-PCA denoising strategies (denoising the entire matrix versus using a sliding window), in terms of apparent SNR, rank selection, noise correlation within and across b-values and quantification of metabolite concentrations and fitted diffusion coefficients. MP-PCA denoising yielded an increased apparent SNR, a more accurate B0 drift correction between shots, and similar estimates of metabolite concentrations and diffusivities compared to the raw data. No spectral residuals on individual shots were observed but correlations in the noise level across shells were introduced, an effect which was mitigated using a sliding window, but which should be carefully considered

Cellular EXchange Imaging (CEXI): Evaluation of a diffusion model including water exchange in cells using numerical phantoms of permeable spheres

Purpose: Biophysical models of diffusion MRI have been developed to characterize microstructure in various tissues, but existing models are not suitable for tissue composed of permeable spherical cells. In this study we introduce Cellular Exchange Imaging (CEXI), a model tailored for permeable spherical cells, and compares its performance to a related Ball \& Sphere (BS) model that neglects permeability. Methods: We generated DW-MRI signals using Monte-Carlo simulations with a PGSE sequence in numerical substrates made of spherical cells and their extracellular space for a range of membrane permeability. From these signals, the properties of the substrates were inferred using both BS and CEXI models. Results: CEXI outperformed the impermeable model by providing more stable estimates cell size and intracellular volume fraction that were diffusion time-independent. Notably, CEXI accurately estimated the exchange time for low to moderate permeability levels previously reported in other studies ($\kappa<25\mu m/s$). However, in highly permeable substrates ($\kappa=50\mu m/s$), the estimated parameters were less stable, particularly the diffusion coefficients. Conclusion: This study highlights the importance of modeling the exchange time to accurately quantify microstructure properties in permeable cellular substrates. Future studies should evaluate CEXI in clinical applications such as lymph nodes, investigate exchange time as a potential biomarker of tumor severity, and develop more appropriate tissue models that account for anisotropic diffusion and highly permeable membranes.Comment: 7 figures, 2 tables, 21 pages, under revie

Diffusion of brain metabolites highlights altered brain microstructure in type C hepatic encephalopathy: a 9.4 T preliminary study

IntroductionType C hepatic encephalopathy (HE) is a decompensating event of chronic liver disease leading to severe motor and cognitive impairment. The progression of type C HE is associated with changes in brain metabolite concentrations measured by 1H magnetic resonance spectroscopy (MRS), most noticeably a strong increase in glutamine to detoxify brain ammonia. In addition, alterations of brain cellular architecture have been measured ex vivo by histology in a rat model of type C HE. The aim of this study was to assess the potential of diffusion-weighted MRS (dMRS) for probing these cellular shape alterations in vivo by monitoring the diffusion properties of the major brain metabolites.MethodsThe bile duct-ligated (BDL) rat model of type C HE was used. Five animals were scanned before surgery and 6- to 7-week post-BDL surgery, with each animal being used as its own control. 1H-MRS was performed in the hippocampus (SPECIAL, TE = 2.8 ms) and dMRS in a voxel encompassing the entire brain (DW-STEAM, TE = 15 ms, diffusion time = 120 ms, maximum b-value = 25 ms/μm2) on a 9.4 T scanner. The in vivo MRS acquisitions were further validated with histological measures (immunohistochemistry, Golgi-Cox, electron microscopy).ResultsThe characteristic 1H-MRS pattern of type C HE, i.e., a gradual increase of brain glutamine and a decrease of the main organic osmolytes, was observed in the hippocampus of BDL rats. Overall increased metabolite diffusivities (apparent diffusion coefficient and intra-stick diffusivity—Callaghan’s model, significant for glutamine, myo-inositol, and taurine) and decreased kurtosis coefficients were observed in BDL rats compared to control, highlighting the presence of osmotic stress and possibly of astrocytic and neuronal alterations. These results were consistent with the microstructure depicted by histology and represented by a decline in dendritic spines density in neurons, a shortening and decreased number of astrocytic processes, and extracellular edema.DiscussiondMRS enables non-invasive and longitudinal monitoring of the diffusion behavior of brain metabolites, reflecting in the present study the globally altered brain microstructure in BDL rats, as confirmed ex vivo by histology. These findings give new insights into metabolic and microstructural abnormalities associated with high brain glutamine and its consequences in type C HE