551 research outputs found

    Keyed Non-Parametric Hypothesis Tests

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    The recent popularity of machine learning calls for a deeper understanding of AI security. Amongst the numerous AI threats published so far, poisoning attacks currently attract considerable attention. In a poisoning attack the opponent partially tampers the dataset used for learning to mislead the classifier during the testing phase. This paper proposes a new protection strategy against poisoning attacks. The technique relies on a new primitive called keyed non-parametric hypothesis tests allowing to evaluate under adversarial conditions the training input's conformance with a previously learned distribution D\mathfrak{D}. To do so we use a secret key κ\kappa unknown to the opponent. Keyed non-parametric hypothesis tests differs from classical tests in that the secrecy of κ\kappa prevents the opponent from misleading the keyed test into concluding that a (significantly) tampered dataset belongs to D\mathfrak{D}.Comment: Paper published in NSS 201

    Potential of production of orange type wines with increased bioactive substance content from new selection grape cultivars from the Republic of Moldova

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    Dry white wines with an increased content of bioactive substances, known as "Orange wines," have become a captivating subject in the wine industry, rooted in the millennia-old tradition of the South Caucasus and gaining global popularity. In the Republic of Moldova, producers such as ”Crama Domească”, ”Gogu Winery”, and ”Vinăria Novac” have explored the "Orange wine" method with indigenous cultivars, bringing innovations to the wine landscape. The study, conducted at the Laboratory of "Biotechnologies and Microbiology of Wine," focused on four promising local cultivars: 'Viorica', 'Floricica', 'Riton', and 'Legenda'. To optimize the content of bioactive substances, the process involved selecting grapes at technological maturity, crushing-destemming with sulfiting, and fermentation with active yeasts. The maceration-fermentation process, ranging from 30 to 90 days, proved to be a crucial factor for the maximum extraction of phenolic substances. Physico-chemical analyses revealed slight changes in titratable acidity and pH, remaining within appropriate limits, with significant concentrations of antioxidant phenolic substances. In this context, "Orange" wines from Moldavian cultivars have demonstrated the potential to provide an innovative alternative in the wine market. However, in light of the results, further studies are recommended to precisely determine the influence of technological procedures on the composition of "Orange" wines and identify other cultivars with increased potential. This approach would strengthen the position of the Republic of Moldova in the production of wines with high bioactive substance content, solidifying its reputation in the global wine landscape

    Anomalous cyclotron mass dependence on the magnetic field and Berry’s phase in (Cd₁-x-γZnxMnγ)₃As₂ solid solutions

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    Shubnikov-de Haas (SdH) effect and magnetoresistance measurements of single crystals of diluted II-V magnetic semiconductors (Cd₁-x-γZnxMnγ)₃As₂ (x+γ= 0.4, y=0.04 and 0.08) are investigated in the temperature range T=4.2 ÷ 300 K and in transverse magnetic field B=0 ÷ 25

    High emission rate of sulfuric acid from Bezymianny volcano, Kamchatka

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    High concentrations of primary sulfuric acid (H2SO4) in fumarolic gases and high emission rate of sulfuric acid aerosol in the plume were measured at Bezymianny volcano, an active dome-growing andesitic volcano in central Kamchatka. Using direct sampling, filter pack sampling, and differential optical absorption spectroscopy measurements, we estimated an average emission of H2SO4 at 243 ± 75 t/d in addition to an average SO2 emission of 212 ± 65 t/d. The fumarolic gases of Bezymianny correspond to arc gases released by several magma bodies at different stages of degassing and contain 25-92% of entrained air. H2SO4 accounts for 6-87 mol% of the total sulfur content, 42.8 mol% on average, and SO2 is the rest. The high H2SO4 in Bezymianny fumaroles can be explained by catalytic oxidation of SO2 inside the volcanic dome. Because sulfate aerosol is impossible to measure remotely, the total sulfur content in a plume containing significant H2SO4 may be seriously underestimated

    Terbium-Macrocycle Complexes as Chemical Sensors: Detection of an Aspirin Metabolite in Urine Using a Salicylurate-Specific Receptor Site

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    Salicylurate (SU) is the major metabolite in urine of acetylsalicylic acid (aspirin) and can be used as a metric to monitor aspirin pharmacokinetics and as an indicator of appendicitis, anemia, and liver disease. Detection in urine and plasma currently requires solvent extraction or other sample handling prior to analysis. We present a simple method to quantify SU in urine via chelation to a terbium binary complex with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-bisacetate (DO2A). Binding of SU to form the [Tb(DO2A)(SU)]− ternary complex triggers intense luminescence under UV excitation due to an absorbance-energy transfer-emission mechanism. Here we report characterization of the [Tb(DO2A)(SU)]− ternary complex and application of this sensitized lanthanide luminescence method to quantify SU in urine samples following a low-dose aspirin regimen

    Influenţa diferitelor proporţii de amestecuri de vinuri roşii asupra indicatorilor senzoriali şi stabilirea parametrilor fizico-chimici a acestora

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    Red sparkling wines produced in Moldova occupy a special place on the wine market, but to improve the quality of the finished product it is necessary to improve the technological regimes for manufacturing base wines for this category of wines. From these reasons, study was conducted on different raw red wines, from classical European varieties Cabernet Sauvignon, Merlot and Pinot Franc, comparing the influence of different composition of red wines blends on the organoleptic indices and establishing their physic-chemical parameters. As a result composition of blends from raw red wines and optimal content of phenolic substances including anthocyans, for red sparkling wine production was establishe

    Two peaks of total current in streamer propagation

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    The numerical simulations of the cathode directed streamer propagation in the discharge gap, with the streamer going out to cathode, are carried out. The processes are found, which take place near anode and contribute to the formation of the first of two maxima of total current time dependence. The factors are considered, which determine the propagation of the ionization process at the final stage, when the streamer approaches the cathode, and the ionization wave is propagating along the cathode surface.Виконане числове моделювання поширення спрямованого до катода стримера у розрядному проміжку з виходом стримера на катод. Знайдені процеси, які відбуваються поблизу анода та сприяють формуванню першого з двох максимумів у залежності повного струму від часу. Розглянуті чинники, які визначають поширення процесу іонізації на завершальній стадії, при наближенні стримера до катода та поширенні хвилі іонізації уздовж поверхні катода.Выполнено численное моделирование распространения направленного к катоду стримера в разрядном промежутке с выходом стримера на катод. Найдены процессы, происходящие вблизи анода и способствующие формированию первого из двух максимумов в зависимости полного тока от времени. Рассмотрены факторы, определяющие распространение процесса ионизации на завершающей стадии, при приближении стримера к катоду и распространении волны ионизации вдоль поверхности катода

    Azimuthal stability of trichel pulses and cathode directed streamers

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    The numerical simulations of negative corona discharge in Trichel pulse mode are carried out with the calculation of evolution of azimuthal perturbations. It is found the azimuthal instability with increment corresponding to avalanche development. This instability is suppressed at the nonlinear stage and does not lead to the process branching. The result is also applicable to the azimuthal instability of the cathode directed streamer, found earlier. The difference in their increments is followed from the difference in courses of the processess, which is discussed.Виконане числове моделювання негативної корони в режимі імпульсів Тричела з розрахунком еволюції азимутальних збурень. Виявлено азимутальну нестійкість з інкрементом, відповідним розвитку лавини. Ця нестійкість пригнічується на нелінійній стадії і не веде до галуження процесу. Результат також застосовується до виявленої раніше азимутальної нестійкості спрямованого до катода стримера. Різниця в їхніх інкрементах випливає з різниці в ході процесів, які обговорюються.Выполнено численное моделирование отрицательной короны в режиме импульсов Тричела с расчетом эволюции азимутальных возмущений. Выявлена азимутальная неустойчивость с инкрементом, соответствующим развитию лавины. Эта неустойчивость подавляется на нелинейной стадии и не ведет к ветвлению процесса. Результат также применим к выявленной ранее азимутальной неустойчивости направленного к катоду стримера. Разница в их инкрементах следует из разницы в ходе процессов, которые обсуждаются
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