488 research outputs found
Hydrological changes in the White Sea during the historical period inferred from analysis of dinocysts
According to available historical evidence, colonization of the White Sea region began in the 9th–8th centuries B.C. [2]. This unique region with ancient residence sites experiences progressively increasing anthropogenic load against the background of natural climatic changes. The intense economic development of the region requires complex ecological and paleogeographic studies aimed at detailed reconstruction of past sedimentation settings.
The analysis of dinocysts, which makes it possible to reconstruct various parameters of water masses washing the Arctic shelf, has become a promising method in paleohydrological studies, widely used in recent years [10, 11]. Dinoflagellates, which represent one of the main phytoplankton groups in the Arctic Seas, the White Sea included, form cysts with biopolymer envelopes, which are preserved in sediments. Thus, information on glacial–hydrological conditions is recorded in marine sediments. In the White Sea, this method was first used for the study of bottom sediments only in 2003 [3, 15].
In this communication, we present the first results obtained during the thorough study of dinocysts in bottom sediment cores from the White Sea, which cover the last 250 years. The study of this microfossil group made it possible to reconstruct in detail changes in glacial–hydrological settings in the sea and reveal their relations with known climatic–hydrological events that occurred in neighboring regions during the historical period
Dinoflagellate cysts in the surface sediments of the White Sea
Dinoflagellate cysts were studied in 42 samples from the surface sediments of the White Sea. The total concentration of dinocysts varies from single cysts to 25 000 cyst/g of dry sediments, which reflects the biological productivity in the White Sea waters and the regional particular features of the sedimentation processes. The highest concentrations are observed in silts; they are related to the regions of propagation of the highly productive Barents Sea waters in the White Sea. Generally, the spatial distribution of dinocysts species in the surface sediments corresponds to the distribution of the major types of water masses in the White Sea. The cysts of the relatively warm-water species (Operculodinium centrocarpum, Spiniferites sp.) of North Atlantic origin that dominate in the sediments indicate an intensive intrusion of the Barents Sea water masses to the White Sea along with hydrological dwelling conditions in the White Sea favorable for the development of these species during their vegetation period. The cold-water dinocyst assemblage (Islandinium minutum, Polykrikos sp.) is rather strictly confined to the inner parts of shallow-water bays, firstly, those adjacent to the Onega and Severnaya Dvina river mouths
High-resolultion reconstruction of Lena River discharge during the Late Holocene inferred from microalgae assemblages
On the basis of a detailed study of the diatom and aquatic palynomorph assemblages and a detailed radiocarbon chronology of sediment cores obtained from the south-eastern inner Laptev Sea shelf adjacent to the Lena Delta the spatial and temporal variability in the Lena River discharge during the last 6 cal. ka were reconstructed. It was shown that in the area adjacent to the Lena Delta variations in surface water salinities, reconstructed using freshwater diatoms as a proxy, were mainly caused by changes in the volume of the Lena River runoff through the major riverine channels Trofimovskaya, Bykovskaya and Tumatskaya. Several paleohydrological phases are recognized:
(i) establishment of modern-like conditions within the eastern Lena River Valley occurred from 6-4.2 cal. ka;
(ii) Lena River outflow increased in north-eastward direction via the Trofimovskaya or Bykovskaya channels from 4.2-2.7 cal. ka, coeval with a reduction of runoff toward the north via the Tumatskaya Channel;
(iii) generally stable hydrological conditions northward of the Tumatskaya Channel and variations in riverine discharge north-eastward of the Trofimovskaya and Bykovskaya channels prevail since 2.7 cal. ka.
Using indicator species of dinocysts as principle marine proxy, an influence of Atlantic water to the southeast inner Laptev Sea shelf could be inferred, possibly along the Eastern Lena paleovalley, brought into this area by winddriven reversed bottom currents.
Zusammenfassung:
Untersuchungen von Diatomeen- und aquatischen Palynomorphen-Vergesellschaftungen wurden an Radiokohlenstoff datierten Sedimentkernen aus der inneren südöstlichen Laptevsee nahe des Lenadeltas durchgeführt. Anhand dieser Daten wurde die zeitliche und räumliche Veränderlichkeit des Flusswasserausstromes der Lena für die letzten 6 ka (Kalenderjahre) rekonstruiert. Zeitliche Veränderungen in den Häufigkeiten von Süßwasserdiatomeen sind begründet durch Wechsel in der Menge des Lenaausflusses durch die drei großen Haupkanäle im Delta: Trofimovskaja, Bykovskja, sowie Tumatskaja. Darauf basierend konnten prinzipiell drei große paläohydrologische Phasen unterschieden werden:
(1) heutigen Verhältnissen vergleichbare Bedingungen wurden östlich des Lenadeltas zwischen 6 und 4.2 ka etabliert;
(2) Erhöhung des Flusswasseraustrags in nordöstliche Richtung über die Kanäle Trofimovskaja und/oder Bykovskaja zwischen 4.2 und 2.7 ka bei gleichzeitiger Reduzierung Richtung Norden via Tumatskaja;
(3) Ausbildung relativ stabiler Bedingungen nördlich des Deltas sowie Auftreten wechselhafter Flusswasserausträgen in östliche Richtung nach 2.7 ka.
Das Auftreten von marinen Dinocysten in den Sedimenkernen belegt den Einfluss von Wassermassen mit vermutlich atlantischem Ursprung. Es ist zu vermuten, dass diese durch windgetriebene Bodenströmungen entlang der alten versunkenen Flusstäler auf den östlichen inneren Schelf verfrachtet werden
Reproductive toxicity of carbon nanostructured material - a promising carrier of drugs in laboratory mice
At the same time, the purpose of this study was to evaluate the reaction of the reproductive system on the carbon nanostructured material "Taunit (multi-walled carbon nanotubes), that was injected to laboratory miceyesBelgorod State Universit
The influence of the microstructure morphology of two phase Ti-6Al-4V alloy on the mechanical properties of diffusion bonded joints
The influence of ultra fine grained (UFG) and coarse grained (CG) microstructure of the titanium alloy Ti-6Al-4V on the strength of a diffusion bonded (DB) joint was studied using a laboratory DB fixture and a new shear test rig. The DB process was carried out at 725°C and 825°C during 2 and 4 hours in a vacuum furnace. Coarsening of grain structure resulting from different DB cycles was quantified. The chain pores were observed at 725°C for both microstructure conditions bonded during 2 hours. The increase of bonding time up to 4 hours leads to subsequent elimination of the pores. The UFG samples bonded at 725°C showed a higher level of the shear strength than CG samples for both bonding times. The CG material demonstrated the highest shear strength after 4 hours of DB bonding at 825°C. The increase of the creep deformation of UFG samples when compared to the CG condition was observed as a result of DB at of 725° C during 4 hours
Evolution of the barrier beaches in the Pechora Sea
The article discusses the main results of the complex investigations of barrier beaches in the Pechora Sea including coastal dynamics and accompanying exogenous processes (eolian transportation), lithological and micropaleontological studies of the sediment sequence and radiocarbon dating. We were the first to reconstruct sedimentation conditions and evolution of these big accumulative forms in the Pechora Sea. Stationary observations on coastal dynamics and the rate of eolian sedimentation allowed estimating the rate of barrier retreat. The mechanism of formation and evolution of dune belts on these barriers is described. Composition of diatom associations and lithological data provide evidence for facial-genetic conditions of sedimentation during accumulation of barriers. Radiocarbon datings corroborate the "young" age of the modern avandune ridges of the barrier beaches
Age- and sex-specific standard scores for the reading the mind in the eyes test
The reliable, valid and economic assessment of social cognition is more relevant than ever in the field of clinical psychology. Theory of Mind is one of the most important socio-cognitive abilities but standardized assessment instruments for adults are rare. The Reading the Mind in the Eyes Test (RMET) is well-established and captures the ability to identify mental states from gaze. Here, we computed standard scores for the German version of the RMET derived from a large, community-dwelling sample of healthy adults (20–79 years). The standardization sample contains 966 healthy adult individuals of the population-based Leipzig Research Center for Civilization Diseases (LIFE) study. Before standardization, weighting factors were applied to match the current sample with distribution characteristics of the German population regarding age, sex, and education. RMET scores were translated into percentage ranks for men and women of five age groups (20–29, 30–39, 40–49, 50–59, 60+ years). Age-specific percentage ranks are provided for men and women. Independent of age, men present a larger variance in test scores compared to women. Within the specific age groups, women score higher and their scoring range is less variable. With increasing age, the scoring variance increases in both men and women. This is the first study providing age- and sex-specific RMET standard scores. Data was weighted to match German population characteristics, enabling the application of standard scores across German-speaking areas. Our results contribute to the standardized assessment of socio-cognitive abilities in clinical diagnostics
Stress and stress-induced disorders
Stress is one of the most significant and widespread medical and social problems in the world and it is the etiological factor in 80% of diseases. In the modern world any person is subject to the influence of stress, regardless of the age and gender differences, culture and social status. Stress is a non-specific reaction of the body to the extreme impact of various factors - stressors. As stressors can be: emotional, social, physical, informational and other factors. In functional and morphological terms, stress is manifests itself as a general adaptation syndrome which mobilizes the body’s resources in order to maintain homeostasis. Stress is characterized by staging. The early period of stress is manifested by transient anxiety, with a decrease in body resistance – it is the first stage of the adaptation syndrome. The second stage of stress is characterized by the functional tension of the body’s systems and adaptation to new conditions. In the case of prolonged stress, the body’s reaction becomes pathological, with the depletion of adaptive reserves and the failure of protective mechanisms. At this stage is increase a vulnerability to any stressors. There is a further violation of the consistency of vital functions, and persistent anxiety is formed. In overwhelming majority of cases, stress-induced anxiety is develop of psychovegetative syndrome. In the case when combined the strategies of coping (it is the second stage of the reaction to stress - the stage of resistance) with stress and if it is interrupted at an early stage, in such a way the somatic symptoms are also interrupted at the stage of autonomic dystonia syndrome. When the persistent stress is, we have a development of the third stage – exhaustion. And against the background of limited adaptive reactions, there is a psychosomatic pathology. The above determines the need for early detection of psychovegetative syndrome and its timely treatment. The optimal choice is the appointment of combined drugs for stress, which have anti-anxiety, sedative and hypnotic effects. The combination of phenobarbital and ethylbromisovalerinate is one of the highly effective and widely used for the relief of stressinduced anxiety and manifestations of autonomic dysfunction, reducing the risk of developing psychosomatic pathology
Pulsed voltage cold atmospheric plasma jet and gold nanoparticles enhance cytotoxic anticancer effect
Efficient and biologically safe mode of cold atmospheric plasma jet (CAPJ) is
crucial for the development of CAPJ-based anticancer therapy. In the experiment
and numerical simulations, by changing the pulse duration of a positive-pulsed
voltage, we found the optimal CAPJ mode with regular streamer propagation. CAPJ
regimes with a maximum discharge current at a temperature T<42 C substantially
suppressed the viability of cancer cells. To enhance cell killing, gold
nanoparticles (NPs) were added to the cells before and after the CAPJ exposure.
Combination of CAPJ, generated with positive pulsed voltage, and gold
nanoparticles decreased viability of NCI-H23 epithelial-like lung
adenocarcinoma, A549 lung adenocarcinoma, BrCCh4e-134 breast adenocarcinoma and
uMel1 uveal melanoma cells. Polyethylene glycol-modified nanoparticles with
attached fluorescent label were used to visualize the uptake of NPs. We
demonstrated that NPs efficiently entered the cells when were added to the
cells just before CAPJ exposure or up to two hours afterwards. The efficiency
ofNPs penetration into cells positively correlated with the induced cytotoxic
effect: it was maximal when NPs was added to cells right before or immediately
after CAPJ exposure. Summarizing, the treatment with optimal CAPJ modes in
combination with modified NPs, bearing the cancer-addressed molecules and
therapeutics may be next strategy of strengthening the CAPJ-based antitumor
approaches.Comment: 19 pages, 8 figures, submitted to Journal of Physics D: Applied
Physics The research was funded by Russian Science Foundation grant number
22-49-08003. The research on uMel1 cells cultivation was funded by Russian
Science Foundation grant number 23-14-0028
Цифровой профиль: понятие, механизмы регулирования и проблемы реализации
The subject of the research is the legal nature of the digital profile of a citizen, as well as a set of legal norms regulating digital profiling relations in Russia.The comparative method, the method of system analysis, as well as the method of legal modeling are used in the article.The purpose of the article is to confirm or disprove the hypothesis that legal regulation is not the only mechanism for regulating relations in the field of digital profiling.The main results, scope of application. The article studies the phenomenon of digital profile, the main approaches to the digital profiling as well as the circumstances that have caused the state's interest in digital profiling. The creation and operation of a digital profile should be aimed at achieving the goal set out in the legislation. The digital profile is a set of relevant, reliable information about individuals and legal entities formed in the unified identification and authentication system or other information systems of state and local government authorities. The formation of a digital profile is carried out in order to provide data to authorities, legal entities and persons who have requested access to this information through the digital profile infrastructure. The analysis of the Russian legal regulation of relations in the field of digital profiling is presented, the problems of enforcement practice are identified. The analysis revealed the main differences between the digital profile and related categories, including social scoring, the unified population register and others. The comparison of a digital profile with a digital avatar and a digital character was carried out. It is extremely important to pay close attention to the problems of digital profiling both at the level of fundamental and applied scientific research. At the state level, it is important to strategically determine what a digital profile is, as well as formulate the main directions of the digital profiling development, challenges and risks. The importance of the development of digital profiling for unified system of public authorities in the Russian Federation is outlined.Conclusions. The analysis of the emerging practice of digital profiling in contemporary society shows that legal regulation does not always allow us to keep up with the rapidly developing relations in this area. The possibility of using other mechanisms should be considered. The use of mechanisms of regulatory experiments can also be considered as special mechanisms for regulating relations in the field of digital profiling. The goal of the research has been achieved, the legal nature of the digital profile has been revealed, approaches to regulating this phenomenon in the conditions of digital transformation have been proposed.Cтавится цель исследовать основные подходы к пониманию и механизмам регулирования цифрового профиля, формируемые в условиях цифровой трансформации. Изучается феномен цифрового профиля, дается анализ состояния российского правового регулирования отношений в сфере цифрового профилирования. Выявляются основные отличия цифрового профиля от смежных категорий, в том числе социального скоринга, единого реестра населения и др. Проводится сравнение цифрового профиля с цифровым аватаром и цифровым персонажем. Делается вывод, что цифровой профиль – это совокупность актуальных достоверных данных и иных сведений о физических и юридических лицах, формируемых в единой системе идентификации и аутентификации или других информационных системах органов государственной власти и местного самоуправления, а также подведомственных им организаций, взаимодействующих с ней посредством единой системы межведомственного электронного взаимодействия, в целях их предоставления с согласия соответствующих граждан или юридических лиц субъектам, запросившим доступ к этим сведениям посредством инфраструктуры цифрового профиля
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