Ridge Area Research Articles

Recent seismic activity in the area of the Gegham volcanic ridge (Armenia)

The Gegham Volcanic Ridge (GVR) is located in the central part of the Neogene-Quaternary volcanic belt formed within the territory of the Armenian Highland. The duration of volcanism within the Gegham Ridge spans from the Late Miocene to the Holocene. The GVR is one of the densest clusters of individual monogenetic volcanoes in the world. The system of the Gegham Ridge faults consists of two components – faults of the axial part of the Gegham Ridge and the Gavaraget Fault. The Gavaraget Fault is the most active one in the Gegham fault system, and was associated with a few historical and recent earthquakes. For investigation of current seismic activity of the study area and to follow possible seismic activity near the volcanic arcs, three more temporary seismic stations were installed in addition to the besides existing seismic network. The received data show that weak earthquakes occur in this area. The recalculation was carried out using the regional velocity model and registrations from all seismic stations covering this area in order to increase the accuracy of epicenter and hypocenter locations. The data show that this area is seismically active in case of small earthquakes (M<=3.4). In this study, source mechanisms of the set of earthquakes that occurred within 2022–2023 have been investigated with high reliability, using digital waveform data recorded by seismic stations of the Armenian seismic networks (including 3 temporary seismic stations mentioned above). Գեղամի հրաբխային լեռնաշղթան (GVR) գտնվում է Հայկական լեռնաշխարհի տարածքում՝ նեոգեն-չորրորդական դարաշրջանում ձևավորված հրաբխային գոտու կենտրոնական մասում: Գեղամի լեռնաշղթայի սահմաններում հրաբխականությունը տևել է սկսած ուշ միոցենից մինչև հոլոցենը: GVR-ը հանդիսանում է առանձին մոնոգենային հրաբուխների՝ աշխարհի ամենախիտ խմբավորումներից (կլաստերներից) մեկը: Գեղամի լեռնաշղթայի խզվածքների համակարգը կազմված է երկու բաղադրիչներից, այն է՝ Գեղամի լեռնաշղթայի առանցքային մասի խզվածքներից և Գավառագետի խզվածքից: Գեղամի խզվածքների համակարգում Գավառագետի խզվածքը ամենաակտիվն է և կապակցվում էր մի քանի պատմական և ժամանակակից երկրաշարժերի հետ: Ուսումնասիրվող տարածքի ընթացիկ սեյսմիկ ակտիվությունը հետազոտելու և հրաբխային աղեղների մոտակայքում հնարավոր սեյսմիկ ակտիվությանը հետևելու նպատակով, ի լրումն գոյություն ունեցող սեյսմիկ ցանցի, տեղադրվել են ևս երեք ժամանակավոր սեյսմիկ կայաններ: Ստացված տվյալները ցույց են տալիս որ այդ տարածքում տեղի են ունենում թույլ երկրաշարժեր: Վերահաշվարկը կատարվել է օգտագործելով արագությունների տարածաշրջանային մոդելը և տվյալ տարածքը ընդգրկող բոլոր սեյսմիկ կայանների գրանցումները՝ նպատակ ունենալով էպիկենտրոնների և հիպոկենտրոնների որոշման ճշգրտումը: Տվյալները ցույց են տալիս, որ այս տարածքը սեյսմիկության առումով ակտիվ է փոքր երկրաշարժերի (M<=3.4) տեսքով: Այս հետազոտությունում բարձր հուսալիությամբ ուսումնասիրվել են 2022–2023թթ. տեղի ունեցած՝ մի խումբ երկրաշարժերի օջախի մեխանիզմները, կիրառելով Հայկական սեյսմիկ ցանցերի սեյսմիկ կայաններում գրանցված թվային ալիքային պատկերները (ներառյալ վերևում նշված 3 ժամանակավոր սեյսմիկ կայանները): Այս ուսումնասիրությունում կիրառվող կատալոգի հիմնական պարամետրերի անորոշությունները նվազագույնի բերելու համար բոլոր տվյալները վերադիրքավորվել են, օգտագործելով տեղական և տարածաշրջանային սեյսմիկ ցանցերի տվյալները: Гегамский вулканический хребет (GVR) находится в центральной части неоген-четвертичного вулканического пояса, сформировавшегося в пределах территории Армянского нагорья. Вулканизм на Гегамском хребте продолжался с позднего миоцена по голоцена. GVR представляет собой один из наиболее густых кластеров отдельных моногенетических вулканов мира. Система разломов Гегамского хребта включает в себе две компоненты – разломы осевой части Гегамского хребта и Гаварагетский разлом. В системе разломов Гегама Гаварагетский разлом является наиболее активным и ассоциировался с несколькими историческими и современными землетрясениями. С целью изучения текущей сейсмической активности исследуемой территории и наблюдения за возможной сейсмической активностью вблизи вулканических дуг, в дополнение к существующей сейсмической сети, были установлены еще три временные сейсмические станции. Полученные данные показывают, что на данной территории происходят слабые землетрясения. Для увеличения точности определения эпицентров и гипоцентров проводился перерасчет с использованием региональной модели скоростей и всех записей с сейсмических станций, охватывающих данную территорию. Данные показывают, что данная территория сейсмически активна в случае слабых землетрясений (M<=3.4). В данном исследовании с высокой степенью надежности исследовались механизмы очагов для набора землетрясений, случившихся в период 2022–2023гг., с применением данных цифровых волновых форм, зарегистрированных на сейсмических станциях сейсмических сетей Армении (включая 3 временные сейсмические станции, упомянутые выше). Все данные были релокализованы с использованием данных с локальной и региональной сейсмических сетей с целью снижения погрешности основных параметров каталога, используемого в данном исследовании.

Modelling of Fluid Permeability at the Interface of the Metal-to-Metal Sealing Surface.

This paper presents a method for modelling the permeability of fluid at the interface formed between flat parallel plates and the sharp-edged ridges of a metal gasket. This work was divided into three stages. In the first stage, numerical calculations simulating the deformation (compression of the gasket) were performed. The calculations were carried out using thermomechanical static analysis with commercial software. The purpose of these calculations was to determine the contact area of the gasket ridges with the plates, the deformation of the gasket ridges, and the reaction force resulting from the degree of compression of the gasket. In the second part of this work, analytical calculations were performed to estimate the tightness level. The analytical model proposed in this paper was based on Darcy's equation, simulating fluid flow through a ring-shaped porous layer. The analytical model also took into account the shape of the roughness profile of the sealed surfaces. A mathematical Ausloos-Berman function based on fractal theory was used to represent it. In the last part of this work, experimental tests were carried out to determine the actual fluid permeability and thus verify the numerical and analytical calculations.

Recent seismic activity in the area of the Gegham volcanic ridge (Armenia)

The Gegham Volcanic Ridge (GVR) is located in the central part of the Neogene-Quaternary volcanic belt formed within the territory of the Armenian Highland. The duration of volcanism within the Gegham Ridge spans from the Late Miocene to the Holocene. The GVR is one of the densest clusters of individual monogenetic volcanoes in the world. The system of the Gegham Ridge faults consists of two components – faults of the axial part of the Gegham Ridge and the Gavaraget Fault. The Gavaraget Fault is the most active one in the Gegham fault system, and was associated with a few historical and recent earthquakes. For investigation of current seismic activity of the study area and to follow possible seismic activity near the volcanic arcs, three more temporary seismic stations were installed in addition to the besides existing seismic network. The received data show that weak earthquakes occur in this area. The recalculation was carried out using the regional velocity model and registrations from all seismic stations covering this area in order to increase the accuracy of epicenter and hypocenter locations. The data show that this area is seismically active in case of small earthquakes (M<=3.4). In this study, source mechanisms of the set of earthquakes that occurred within 2022–2023 have been investigated with high reliability, using digital waveform data recorded by seismic stations of the Armenian seismic networks (including 3 temporary seismic stations mentioned above). Գեղամի հրաբխային լեռնաշղթան (GVR) գտնվում է Հայկական լեռնաշխարհի տարածքում՝ նեոգեն-չորրորդական դարաշրջանում ձևավորված հրաբխային գոտու կենտրոնական մասում: Գեղամի լեռնաշղթայի սահմաններում հրաբխականությունը տևել է սկսած ուշ միոցենից մինչև հոլոցենը: GVR-ը հանդիսանում է առանձին մոնոգենային հրաբուխների՝ աշխարհի ամենախիտ խմբավորումներից (կլաստերներից) մեկը: Գեղամի լեռնաշղթայի խզվածքների համակարգը կազմված է երկու բաղադրիչներից, այն է՝ Գեղամի լեռնաշղթայի առանցքային մասի խզվածքներից և Գավառագետի խզվածքից: Գեղամի խզվածքների համակարգում Գավառագետի խզվածքը ամենաակտիվն է և կապակցվում էր մի քանի պատմական և ժամանակակից երկրաշարժերի հետ: Ուսումնասիրվող տարածքի ընթացիկ սեյսմիկ ակտիվությունը հե-տազոտելու և հրաբխային աղեղների մոտակայքում հնարավոր սեյսմիկ ակտիվությանը հետևելու նպատակով, ի լրումն գոյություն ունեցող սեյսմիկ ցանցի, տեղադրվել են ևս երեք ժամանակավոր սեյսմիկ կայան-ներ: Ստացված տվյալները ցույց են տալիս որ այդ տարածքում տեղի են ունենում թույլ երկրաշարժեր: Վերահաշվարկը կատարվել է օգտագործելով արագությունների տարածաշրջանային մոդելը և տվյալ տարածքը ընդգրկող բոլոր սեյսմիկ կայանների գրանցումները՝ նպատակ ունենալով էպիկենտրոնների և հիպոկենտրոնների որոշման ճշգրտումը: Տվյալները ցույց են տալիս, որ այս տարածքը սեյսմիկության առումով ակտիվ է փոքր երկրաշարժերի (M<=3.4) տեսքով: Այս հետազոտությունում բարձր հուսալիությամբ ուսումնասիրվել են 2022–2023թթ. տեղի ունեցած՝ մի խումբ երկրաշարժերի օջախի մեխանիզմները, կիրառելով Հայկական սեյսմիկ ցանցերի սեյսմիկ կայաններում գրանցված թվային ալիքային պատկերները (ներառյալ վերևում նշված 3 ժամանակավոր սեյսմիկ կայանները): Այս ուսումնասիրությունում կիրառվող կատալոգի հիմնական պարամետրերի անորոշությունները նվազագույնի բերելու համար բոլոր տվյալները վերադիրքավորվել են, օգտագործելով տեղական և տարածաշրջանային սեյսմիկ ցանցերի տվյալները: Гегамский вулканический хребет (GVR) находится в центральной части неоген-четвертичного вулканического пояса, сформировавшегося в пределах территории Армянского нагорья. Вулканизм на Гегамском хребте продолжался с позднего миоцена по голоцена. GVR представляет собой один из наиболее густых кластеров отдельных моногенетических вулканов мира. Система разломов Гегамского хребта включает в себе две компоненты – разломы осевой части Гегамского хребта и Гаварагетский разлом. В системе разломов Гегама Гаварагетский разлом является наиболее активным и ассоциировался с несколькими историческими и современными землетрясениями. С целью изучения текущей сейсмической активности исследуемой территории и наблюдения за возможной сейсмической активностью вблизи вулканических дуг, в дополнение к существующей сейсмической сети, были установлены еще три временные сейсмические станции. Полученные данные показывают, что на данной территории происходят слабые землетрясения. Для увеличения точности определения эпицентров и гипоцентров проводился перерасчет с использованием региональной модели скоростей и всех записей с сейсмических станций, охватывающих данную территорию. Данные показывают, что данная территория сейсмически активна в случае слабых землетрясений (M<=3.4). В данном исследовании с высокой степенью надежности исследовались механизмы очагов для набора землетрясений, случившихся в период 2022–2023гг., с применением данных цифровых волновых форм, зарегистрированных на сейсмических станциях сейсмических сетей Армении (включая 3 временные сейсмические станции, упомянутые выше). Все данные были релокализованы с использованием данных с локальной и региональной сейсмических сетей с целью снижения погрешности основных параметров каталога, используемого в данном исследовании.

Novel High Efficiency V‐Band Pure TEM D‐PRGW Antenna for 5G mmWave Applications

ABSTRACTThis paper starts with the proposal of an enhanced version of a planar rectangular slot antenna fed by the quasi‐TEM printed ridge gap waveguide (PRGW), attended with a numerical study of a miniaturization procedure showing the limitations of the conventional PRGW‐based antennas. Then innovative solution is introducing a new miniaturized pure TEM wide‐band slot antenna utilizing double PRGW (D‐PRGW) technology; the proposed approach is self‐packaged and shows high potential for enhancing antenna performance, particularly in terms of bandwidth, gain, and compactness. This technology is featured with low loss, high performance, and compact size; it consists of surrounding the ridge area with a double layer of electromagnetic band gap (EBG) lattice instead of one to eliminate the surface waves effectively and keep the signal completely confined inside the ridge area with strict minimum rows of EBG. Therefore, a broad impedance matching bandwidth (|S11| ≤ −10 dB) of 33.33% is obtained from 50 to 70 GHz, which covers the unlicensed NR parts (n262; amp; n263) of the V band. Furthermore, the antenna achieves a peak gain of approximately 16 at 65 GHz while the overall efficiency remains above 90% across the entire operating frequency band. The high performance along with the compact size of this novel design makes it a good candidate for 5G wireless communications applications centered around 60 GHz.

Bone augmentation using bioresorbable mesh domes containing bone graft granules

Bone graft granules are valuable tools for ridge area bone grafting owing to their ease of manipulation and interconnected porous structure. Guided bone regeneration (GBR) using barrier membranes is commonly used for alveolar ridge augmentation; however, the surgical procedures are technically complicated. In this study, we fabricated bioresorbable mesh domes (BMDs) using two types of Vicryl mesh (woven and knitted types) containing carbonate apatite granules. BMD samples were prepared in three groups: upper sides made from the woven type (UW) and lower sides made from the woven type (LW) (the UW/LW group), upper sides made from the woven type (UW) and lower sides made from the knitted type (LK) (the UW/LK group), and upper sides made from the knitted type (UK) and lower sides made from the knitted type (LK) (the UK/LK group). The samples were subsequently implanted into rabbit calvaria, and radiomorphometric and histological analyses were conducted. The UK/LK group exhibited enhanced appositional bone formation because the knitted mesh on the skin side prevented the infiltration of a substantial amount of fibrous tissue. This increase in bone formation could be attributed to the interaction between granules and osteoprogenitors that pass through the mesh from the host bone. Conversely, the UW/LW and UW/LK groups presented limited appositional bone formation. Compared with knitted mesh, woven mesh might tend to be absorbed over a short span, allowing fibrous tissue invasion and inhibiting new bone formation. Additionally, BMDs could retain granules in a targeted location and avoid displacement of the granules to unintended locations.Graphical

Geophysical characterization and 2D gravimetric modeling: Application to tectonic control of the Vitória-Trindade Ridge (VTR–ES, Brazil)

There are numerous inquiries regarding the origin and development of the Vitória-Trindade Ridge (VTR) in eastern Brazil, a major tectonic feature composed of seamounts, guyots, banks, and islands, prompting extensive studies in the region. These investigations aim to create a more precise crustal model to aid in understanding various geological phenomena, such as the separation of South America from Africa, the interaction between continental and oceanic crusts, and the behavior of oceanic fracture zones. These zones may have served as conduits for magma feeding into the ridge and adjacent areas, or the seamounts could have formed due to a fixed mantle plume related to the West-East trend. This study focuses on exploring the tectonic structure of the region, particularly the subsurface of the VTR, utilizing geophysical data modeling techniques. This includes data from topography, gravimetric and magnetic anomalies, and analysis of reflection seismic lines. The research aims to accurately characterize the geological and geophysical context of the continental margin and some igneous features in the offshore region of the Espírito Santo and Bahia states. The anomalous hotspots correlate with pre-existing fracture zones resulting from the Mesozoic rifting of South American and African continents, which due to later tectonic episodes, have masked traces of deep-seated tectonic structures. The integration of geophysical methods, particularly gravimetry and magnetometry, when combined with reflection seismic data and 2D modeling techniques, offer insights into the geodynamic processes involved in the formation of the volcanic ridge. The results obtained showed the interference generated by magmatism in the oceanic crust and the transition zone. The seismic data allowed the visualization of the approximate geometries and interrelationships of some volcanic edifices that are compared with the Davis Bank, located in the central region of the VTR.

New data on the morphology of Ascarophis parupenei (Nematoda: Cystidicolidae), an intestinal parasite of the marine fish Parupeneus indicus in the Indian Ocean, revealed by SEM.

Scanning electron microscopy studies of three paratype specimens (two males and one female) of Ascarophis parupenei Moravec, Orecchia & Paggi, 1988, an intestinal parasite of the marine fish Parupeneus indicus (Shaw) in the Indian Ocean, made it possible to redescribe in detail the cephalic structures of this nematode as well as the morphology of the male caudal end. The presence of non-bilobed sublabia, phasmids in both males and females, bifurcated deirids, well-developed precloacal cuticular ridges (area rugosa) and a ventral median caudal protuberance in the male are reported in this species for the first time. The general morphology and measurements of A. parupenei somewhat resemble those of Rasheedia novaecaledoniensis Moravec & Justine, 2018 described from the same host species (P. indicus) from off New Caledonia, but both species clearly differ from each other by the shape and structure of pseudolabia and the anterior portion of the digestive tract, belonging thus to different nematode families (Cystidicolidae and Physalopteridae, respectively).

Bound state in the continuum enabled ultralong silicon ridge waveguide grating antennas for integrated LiDAR applications.

As a novel method for solid-state light detection and ranging (LiDAR), optical phased arrays (OPAs) cater to the growing market requirement for mass-produced chip-scale beam steering devices. Waveguide grating antennas (WGAs) with low loss, high efficiency and large emitting aperture are strongly desirable to achieve low beam divergence and high resolution for OPAs. In this paper, we report two kinds of silicon ridge-waveguide-based WGAs with ultra-sharp instantaneous field-of-view (IFOV) for LiDAR applications. The ridge-concave WGA (RCC-WGA) and ridge-convex WGA (RCV-WGA) are designed on account of both sides of ridge area have relatively weak mode field distribution. Lateral quasi-bound state in the continuum (L-BIC) is utilized to further suppress side scattering and improve the emission efficiency. The RCC-WGAs and RCV-WGAs are fabricated on silicon-on-insulator (SOI) platform with 220 nm device layer and foundry compatible etching depths. The measured losses are as low as 2.64 and 2.40 dB/mm at 1550 nm wavelength. The antenna length can up to 6 mm, with theoretical beam divergences of 0.0195° and 0.0175° at the wavelength of 1550 nm, while the experimental results are 0.0251° and 0.0237°, respectively. The proposed low-beam-divergence WGAs are promising in high resolution solid-state LiDAR applications.

A method of impressing flabby ridge

Flabby ridge remained a challenge in dental clinical practice to obtain an accurate impression for edentulous patients. During the traditional impression making process, the excessive and displaceable soft tissue are usually compressed. In this article, we presented an impression method by using a modified special stock tray, impression compound and polyvinyl siloxane impression materials.•the suitable stock tray was modified with holes about 5 mm diameter in the corresponding area to the crest of the flabby ridge.•the primary impression was made by position the modified tray with the softened compound impression on the edentulous ridge, avoiding the area of the flabby ridge.•the final accurate impression was obtained by using the light body polyvinyl siloxane impression material.

Strategies for Reducing the Ohmic Resistance in a Proton Exchange Membrane Electrolysis Cell

Ohmic polarization caused by the contact resistance between components and their own bulk resistance is the main polarization loss in proton exchange membrane electrolysis cells. To investigate this, we adopted an electrolysis cell with an active area of 25 cm2 and explored methods of reducing ohmic resistance. First, two kinds of polar plate were designed to investigate the contact area between transport layer and catalytic layer. The results showed that the polar plate with the higher ridge area made the transport layer and catalytic layer achieve good contact, resulting in an ohmic resistance decreases of 17.5 mΩ cm2 when the contact area increases from 16.85 to 21.6 cm2. Second, Pt coating was used to prevent oxidation of the titanium felt and improve electrolytic performance. Sputtering titanium felt exhibits the best performance with the electrolysis voltage of 1.814 V at 2 A cm−2. Finally, we studied different proton exchange membranes and analyzed the performance and hydrogen permeation rate with the self-made membrane electrode, finding that the electrolytic voltage of the Solvay E98–05 S reaches 1.733 V at 2 A cm−2 due to the minimum thickness and the highest conductivity, and the H2 permeation current density is only 2.184 mA cm−2.

AM-UNet: Field Ridge Segmentation of Paddy Field Images Based on an Improved MultiResUNet Network

In order to solve the problem of image boundary segmentation caused by the irregularity of paddy fields in southern China, a high-precision segmentation method based on the improved MultiResUNet model for paddy field mapping is proposed, combining the characteristics of paddy field scenes. We introduce the attention gate (AG) mechanism at the end of the encoder–decoder skip connections in the MultiResUNet model to generate the weights and highlight the response of the field ridge area, add an atrous spatial pyramid pooling (ASPP) module after the end of the encoder down-sampling, use an appropriate combination of expansion rates to improve the identification of small-scale edge details, use 1 × 1 convolution to improve the range of the sensory field after bilinear interpolation to increase the segmentation accuracy, and, thus, construct the AM-UNet paddy field ridge segmentation model. The experimental results show that the IoU, precision, and F1 value of the AM-UNet model are 88.74%, 93.45%, and 93.95%, respectively, and that inference time for a single image is 168ms, enabling accurate and real-time segmentation of field ridges in a complex paddy field environment. Thus, the AM-UNet model can provide technical support for the development of vision-based automatic navigation systems for agricultural machines.

Dense Amorphous Passivation Layer Formed on Aluminum Alloy Surfaces by Femtosecond Laser-Assisted Oxygen-Rich Doping.

Aluminum (Al) alloy surfaces are prone to serious corrosion in humid and salt-laden environments, which promotes the development of numerous protective approaches. Although the amorphous state is more conducive to improve corrosion resistance compared with the crystalline state, it still faces coating design problems like insufficient adhesive strength and flaking-off tendency. Here, we propose a strategy of femtosecond laser-assisted oxygen-rich doping to in situ create a dense high-quality passivation layer on Al alloy surfaces. With respect to the femtosecond laser processing in traditional air ambience, the material surface modifications within the oxygen-rich environment demonstrate some distinctiveness. For the ridge area of the laser ablation grooves, the oxidation surface is separated into two layers: the outer region presents a loose and porous appearance similar to the observations in the air ambience, while the inner region exhibits complete and homogeneous oxidation, especially associated with the continuous distribution of the amorphous substance, in sharp contrast to the nanoscale discrete amorphous formation in the air case. Simultaneously, the high degree of material oxidization with the amorphous phase is also developed on the wallside area of the groove valleys, which is much different from the incomplete oxidation in the air ambience. As a result, the measured corrosion current decreases by 49 times to a value of Icorr = 1.19 × 10-10 A/cm2 relative to the laser treatment in the air environment. Such a method offers the prospect for elevating the anticorrosion performance of metal surfaces.

Modification on Window Technique in Full Edentulous Patient with Hyperplasia

Complete denture is often used by patients that have edentulism. However, a long-term denture wearers commonly showed the hyperplastic growth of tissue called hyperplasia. This condition will present some difficulties for impression and retention. A 77 year old male patient reported to the RSGM UMY with a loose-fitting denture. He has been using it for 10 years. His old denture has suction cup on the palatal which no longer retentive and stable. The clinical examination showed the maxillary and mandibular complete edentulous ridge with flabby ridge area in the maxillary and mandibular anterior region. Patient is given treatment complete denture with acrylic resin material. In this case, window technique is used as the impression technique for a flabby ridge. Denture-induced hyperplasia is a condition of enlarged of fibrous tissue that could leads to poor denture retention, support, and stability. In the presence of hyperplasia, fabrication of as stable denture can be very arduous challenge. Special impression technique, like window technique frequently used on a case with flabby ridge. Window technique is a technique which use medium body impression material for the un-displaceable tissue whereas the flabby tissue impressed by using light body elastomer impression that must be freed from pressure. In patient with flabby ridge or hyperplasia due to denture, fabrication of impression need special technique like window technique which can be proven to ensure a final impression of the flabby ridge to improve denture stability, retention, support, and patient comfort.

Опасность оползневой деятельности в Моздокском районе Республики Северная Осетия – Алания

The object of the study is landslide activity in the Mozdok administrative region of the Republic of North Ossetia-Alania. The work examines the results of systematization and analysis of various sources containing information about the activity and danger of landslide processes in this area in the 21st century. The conditions, causes, activity and danger of landslide activations in the region are characterized. It is noted that the activity of landslide processes in the study area is mainly due to natural factors, however, recently the emergence of new landslide forms and the activation of old ones most often occur under technogenic influence. Landslide activity in the region is observed on the ledge of the right bank alluvial-accumulative terrace of the river. Terek, where most of the settlements of the region are located, as well as the northern slope of the Tersky ridge and in the area of the watershed ridge of the Sunzhensky ridge. The most significant activation of landslide processes (causing deformation of residential buildings and roadways of streets) was observed in the villages of Maly Malgobek, Predgornoye and Sukhotskoye. Since 2021, after the reconstruction of the Zilga – Mozdok highway, significant landslide deformations and destruction of the roadway have been observed on the section of the road between the villages of Khurikau (Mozdok district) and Old Batako (Right Bank district). The article provides information about the activity of landslide activity and the scale of deformations and destruction of residential and transport infrastructure that occurred in the area. Analysis of the socio-economic consequences of the landslide activations shows a significant degree of their danger to the life of the population in the Mozdok region.

Characteristics of environmental conditions during the accumulation of lake bottom sediments in the Mustatunturi ridge area (Kola region)

A comprehensive study (lithological study, diatom analysis, radiocarbon dating, grain-size and loss on ignition (LOI) analyses) of bottom sediments of the lake located at altitude 31.2 m above sea level in the Mustatunturi ridge area (Kola region) was carried out. It has been established that the beginning of sedimentation in the lake basin occurred in the early Holocene under brackishwater conditions. The transition zone from marine to freshwater sediments were formed while the sea coastline has been retreating. Freshwater sediments were formed when the basin of the studied lake was disconnected from the sea.

ВЫЯВЛЕНИЕ ПАЛЕОГИДРОДИНАМИЧЕСКИХ ОБСТАНОВОК ОСАДКОНАКОПЛЕНИЯ ПО ДАННЫМ ГРАНУЛОМЕТРИЧЕСКОГО АНАЛИЗА ДОННЫХ ОТЛОЖЕНИЙ МАЛЫХ ОЗЕР ШОКШИНСКОЙ ГРЯДЫ (КАРЕЛИЯ)1

The paper examines the grain size distribution of bottom sediments of lakes in the Shoksha Ridge area, Karelia, to elucidate howdeglaciation and formation of the Onego Ice Lake basin proceeded. A sequence of bottom sediments of Lake Anashkino and two sediment sequences of Lake Rzhanoe were studied, and lithostratigraphy of the sediment cores was described. The grain size compositions of the 9.32-10.32m sequence from Lake Anashkino and the 2.5-6.52 m sequence from Lake Rzhanoye were analyzed. The study revealed features of the bottomsediment fractions distribution along the depth of occurrence. Paleo-hydrodynamic sedimentation environments were identified using grain sizeanalysis. Lake Anashkino bottom sediments of a 9.96–10.31 m horizon, represented by silt and fine-grained sand, were deposited under conditions of highly dynamic shallowing (decrease in the water level of Onego Ice Lake). The upper part of sediments (9.32–9.92 m), represented by clayey silt mixed with fine-grained sand, accumulated under weak flow conditions. Paleo-hydrodynamic sedimentationenvironments in Lake Rzhanoye were characterized by alternation of highflow conditions (5.36-6.23 m, 6.31-6.32 m, 6.47-6.48 m) and weak flowconditions (2.50-4.88 m, 6.28-6.29 m, 6.30-6.31 m, 6.37-6.45 m, 6.51-6.52 m). This is possibly due to the dynamics of the decrease in the waterlevel of Onego Ice Lake and the formation of small isolated lakes.In the process of the formation of bottom sediments of small lakes of the Shoksha Ridge during the period of intensive changes in thelandscapes, outlines and levels of Onego Ice Lake at the transition from the late Pleistocene to Holocene, against a shift from nival to humid climate,we note a change in sedimentation conditionsin the bottom sediments of the two studied lakes – Anashkino and Rzhanoe – from highly dynamic(flowing conditions, decrease in water level of Onego Ice Lake) to weakly flowing, in the conditions of isolation of the lakes and formation ofmodern small lakes.

Geochronological Study of Hydrothermal Precipitates in the Northern Equatorial Area of the Mid-Atlantic Ridge

Geochronological Study of Hydrothermal Precipitates in the Northern Equatorial Area of the Mid-Atlantic Ridge

지리산국립공원 구상나무의 수직적 분포 현황

This study was conducted to provide raw data for predicting, preserving, and managing distribution changes due to climate change in the future by investigating the vertical distribution of Abies Koreana in Jirisan National Park. A. Koreana are a major tree species that make up subalpine vegetation in republic of Korea and are particularly sensitive to climate change, so vertical distribution changes can serve as an indicator for these changes. To this end, the vertical distribution status of A. Koreana in major trails in Jirisan National Park was investigated in 2014 and 2021, and the distribution change according to the time series was confirmed. As a result, A. Koreana trees showed a lower distribution limit in the range of 800-890m in the northern part of the main ridge in the valley and 900-1080m in the southern part. In the ridge, the distribution lower limit was shown in the range of 1,220-1,420m in the northern area of the main ridge and 1,030-1,200m in the southern area. This vertical distribution difference was seen as a result of microclimate effects caused by the location environment between the northern and southern regions, starting from the valley, ridge, and main ridge. The vertical distribution change according to the time series has not yet appeared, and generally, A. Koreana trees located on the trail showed a healthy state. Through this study, the vertical distribution of A. Koreana trees in Jirisan National Park was identified, and it is believed that future changes in subalpine conifers due to climate change should be recorded and conservation plans should be prepared.

Influence of antiresorptive/antiangiogenic therapy on changes in periodontal and oral tissue structures: a histomorphometrical analysis in rats

ObjectiveThe objective of this study was to investigate the influence of various antiresorptive and antiangiogenic medications on morphological changes in periodontal and oral tissue structures.Materials and methodsFifty-five Wistar rats randomly received dual application (i.e., at baseline and after 12-weeks) one of the following medications: (1) amino-bisphosphonate [zoledronate (Zo)], (2) RANKL inhibitor [denosumab (De)], (3) antiangiogenic [bevacizumab (Be)], (4) Zo + Be, (5) De + Be or (6) no medication [Control (Co)]. Periodontal and oral tissue biopsies were obtained at 17 (n = 21 animals, Phase 1, (De = 3, De + Be = 3, Zo = 5, Be = 3, Zo + Be = 2, Co = 5) and 29 (n = 34 animals, (De = 8, De + Be = 6, Zo = 2, Be = 7, Zo + Be = 4, Co = 7, Phase 2) weeks after the second drug application. The following outcomes were histomorphometrically assessed: periodontal space width in the coronal (PLS-C, mm) and apical sections (PLS- A), number of empty alveolar bone lacunae in the coronal, apical sections and at the apex at respective tooth sites (EL – C, EL- A, EL- Ap), mucosal thickness at edentulous alveolar ridge areas (MT, mm), and, when present, associated areas of inflammatory cell infiltrates (ICI, mm2).ResultsComparable mean PLS-C, PLS-A, ET-A, ET-C, ET-Ap, and MT values were observed in all experimental groups after Phases 1 and 2. The presence of ICI was identified in 3 animals in the Co group (Phase 1: 1, Phase 2: 2), and 17 animals in the test groups (Phase 1: 4; Phase 2: 14). The estimated ICI surface area was significantly higher in the Zo + Be group, followed by the Zo and Be groups compared to that measured in the Co group. The time (i.e., Phases 1 and 2) was not found to be a predictor for the extent of the ICI area. In all groups, the EL-C, EL-A, and EL-Ap values were significantly higher after Phase 2 compared to those assessed after Phase 1. The MT values were significantly reduced in all groups after Phase 2 compared to those measured after Phase 1.ConclusionsThe present evaluation was not able to find any morphological effects of different antiresorptive and antiangiogenic medications on periodontal and oral tissue structures. The presence of inflammatory cell infiltrates was more frequently observed in the animals administered with antiresorptive and antiangiogenic medications as well as combinations thereof.Clinical relevanceAdministration of antiresorptive and antiangiogenic medications may be capable of inducing inflammatory reactions in periodontal tissues.

ОБОСНОВАНИЕ ПАРАМЕТРОВ ГРЕБНЯ ПРИ ВОЗДЕЛЫВАНИИ КАРТОФЕЛЯ

It is necessary to form such a ridge in volume using the ridge technology of soil cultivation, which would allow the development of the necessary potato root system, and it would be possible to obtain the planned harvest with a sufficient amount of moisture and nutrients. The purpose of the study is to substantiate the parameters of the ridge. Mathematical methods were used in the study. It has been established that during the growing season of potatoes, a change in the given shape of the ridge occurs, since under the influence of precipitation, watering, soil self-settling, and shedding, the trapezoidal shape transforms into a round one. The need to create a fine-clump soil structure in the ridge, to create a groove on the top of the ridge and its use in ridge technology for potato production was justified. The ridge section parameters were adopted based on these data. Analytical dependencies were obtained to determine the cross-sectional area of the trapezoidal ridge, both newly formed and with an additional groove required for irrigation during the potato growing season. The required volumes of soil in the formed ridge were determined. Observations and calculations carried out for planting potatoes with a row spacing of 75 cm show that the shape of the ridge by the time of harvesting undergoes significant changes from the original. The volume of soil in the ridge at the beginning of its formation and before harvesting differs by 4.18%.