Научный архив: статьи

Introduction/purpose: The study of the theory of fuzzy sets was prompted by the presence of uncertainty as an essential part of real-world problems, leading Zadeh to address the problem of indeterminacy. The notion of fuzzy logic was introduced by Zadeh. Unlike traditional logic theory, where an element either belongs to the set or does not, in fuzzy logic, the affiliation of the element to the set is expressed as a number from the interval [0, 1].

Methods: The theory of a fixed point in fuzzy metric spaces can be viewed in different ways, one of which involves the use of fuzzy logic. Fuzzy metric spaces, which are specific types of topological spaces with pleasing ”geometric” characteristics, possess a number of appealing properties and are commonly used in both pure and applied sciences. Metric spaces and their various generalizations frequently occur in computer science applications. For this reason, a new space called a Pompeiu-Hausdorff fuzzy b-metric space is constructed in this paper. Results: In this space, some new fixed point results are also formulated and proven. Additionally, a general common fixed point theorem for a pair of multi-valued mappings in Pompeiu-Hausdorff fuzzy b-metric spaces is investigated. The findings obtained in fuzzy metric spaces, such as those discussed in the article of Shen, Y. et al. (2012. Fixed point theorems in fuzzy metric spaces. Applied Mathematics Letters, 25, pp.138-141), are generalized by the results in this paper, and additional specific findings are produced and supported by examples.

Conclusions: The study of denotational semantics and their applications in control theory using fuzzy b-metric spaces and Pompeiu-Hausdorff fuzzy b-metric spaces will be an important next step.

In order to promote cultural variety, encourage local involvement, and provide a voice to underrepresented groups, community radio stations (CRS) have become essential venues. Using information from 339 publications in the English language indexed in the Scopus database between 2000 and 2024, this bibliometric analysis attempts to map the research landscape on CRS methodically over the previous 20 years. This timeframe was chosen to capture significant developments in community radio stations, including policy shifts, technological advancements, and the rise of CRS movements in regions like South Asia, Africa, and Latin America. The analysis pinpoints important patterns in the field’s publication output, research hotspots, significant writers, and foundational publications. The data shows a consistent rise in scholarly interest, especially concerning the contribution of CRS to media democratization, community empowerment, and social transformation. A thematic analysis reveals recurrent research themes, such as CRS’s role as an alternative medium, how it affects local development, and the difficulties it faces in maintaining operations. Citation analysis reveals patterns of scholarly collaboration by highlighting the most significant publications and the growth of research networks. This study highlights how CRS has influenced the media environment and how they might support community-based projects. This work advances theoretical knowledge of CRS’s development and continued significance by thoroughly analyzing the scholarly discourse on the subject.

One of the scientific approaches to correcting fibrotic myocardium is the development of regenerative medicine methods, which involve tissue therapy. The present study aimed to identify morphological and functional changes in the fibrous myocardium of rats after cryoinjury and the use of allogeneic biomaterial. The study included 80 Wistar rats divided into two groups, the control and the experimental group. All rats underwent a thoracotomy under general anesthesia with Xylazine and Zolazepam, and a section of the left ventricle was frozen with a cooled metal stylet. In the experimental group, a repeated thoracotomy was performed 45 days after cryodestruction. An allogeneic biomaterial suspension, dispersed from an acellular extracellular matrix with a particle size of 50 to 80 μm, was then injected intracardially into the area of cryogenic myocardial necrosis at a dose of 3 mg per animal. Forty-five days after the allogenic biomaterial injection, the tolerance of rats to physical activity was assessed using the modified Porsolt test. After the tolerance test, the weight of the heart, the thickness of the left ventricular wall, the thickness of the scar, and the diameter of the damaged area were measured. Three myocardium samples were taken from each animal and processed for examination using a light microscope. Histological examination of the myocardium samples revealed an avascular scar. In the experimental group, the thickness of the muscular part was significantly higher than in the control group. Meanwhile, heart weight didn’t differ much between the control and experimental group. The exercise tolerance of rats in the experimental group was higher than that of the control group and did not differ significantly from the intact values. The presented results supported the allogeneic biomaterial’s positive influence on the rats’ myocardium structure that had undergone cryogenic destruction.

The possibility of synthesising ion-substituted forms of hydrated silver antimonates Ag2γH2-2γSb2O6·2H2O has been studied. For the synthesis, the method of mechanochemical activation of the components of an inorganic mixture consisting of polyantimonic acid (PAA) with H2Sb2O6·2H2O composition and silver nitrate with the concentration range (γ) from 0.0 to 1.0 has been applied. The results of studies of the phase composition of the synthesized compounds and their structural features are presented. Using the Rietveld method, the parameters of the crystal lattice of PAA hydrated ionsubstituted silver forms with a pyrochlore-type structure have been refined. The model for the occupation of metal ions by crystallographic positions has been proposed: the framework of the structure of the compounds is formed by 16c- and 48f -positions, in which Sb5+ and O2- are statistically located; hydrated oxonium ions (H3O+) and silver ions occupy 16d- and 8b-positions respectively. It has been shown that the synthesis of silver forms of PAA is preferably carried out by the mechanochemical synthesis, which results in the complete substitution of proton groups by silver ions in the structure of the compounds.

By the aid of Appell, Humbert and Bessel functions, the integral representations for a Kamp´e de F´eriet function are found. The validity of integral representations for a Kamp´e de F´eriet function of general form are proved. Conditions, under which these representations are expressed in terms of products of two generalized hypergeometric functions are found. Examples, in which the integral representation of the Kamp´e de F´eriet function containing Appell, Humbert or Bessel functions, are identified.

In this work, the contribution of the free electron gas subsystem to the total entropy change during the phase transition in La(Fe, Co)13-xSix compounds has been evaluated. This estimation has been carried out using experimental data on the measurement of transport properties, in particular the Seebeck and Hall effects. In this work we have also analysed possible errors in the calculation of the carrier concentration in ferromagnets based on the results of measurements of the normal Hall coefficient. It was found that in the compounds studied it is necessary to take into account the contributions of magnetoresistance and paraprocess when calculating R0.

Doktor Gulnor Djumaeva monografiyasi uchun Markaziy masala sifatida uchta taniqli xalqaro aktyorlar-Xitoy, AQSh va Rossiyaning dinamik Markaziy Osiyo muhiti doirasidagi strategik o’zaro aloqalari tanlangan. U akademik va ilmiy jamoatchilikka Toshkentdagi universitetning taniqli olimi va katta ilmiy xodimi sifatida tanilgan. 30 dan ortiq ilmiy ishlar muallifi. Ilmiy tadqiqotlarning asosiy yo’nalishi global geosiyosiy manfaatlar va ularning Markaziy Osiyoga ta’siri hisoblanadi.

Ushbu hujjatda dengizga chiqmagan Markaziy Osiyoning savdo dinamikasi ko’rib chiqilgan bo’lib, unda O’zbekistonga alohida e’tibor qaratilgan. Ikki tomonlama dengizga chiqa olmaydigan mamlakat bo’lgan O’zbekistonning geografik kamchiliklari transport xarajatlarining yuqoriligi va tranzit muddatlarining uzayishi tufayli uning savdo raqobatbardoshligiga sezilarli darajada to’sqinlik qilmoqda. Tarixan paxta, oltin va tabiiy gaz eksporti kabi tovarlarga bog’liq bo’lgan O’zbekiston iqtisodiyoti jahon bozoridagi tebranishlarga nisbatan zaifligicha qolmoqda. Ushbu muammolarni yumshatish va savdo salohiyatini oshirish uchun tadqiqot qo’shimcha qiymatli tarmoqlarni diversifikatsiya qilish va savdo logistika infratuzilmasini takomillashtirish zarurligini ta’kidlaydi. Gravitatsion savdo modelini qo’llagan holda, ushbu hujjat Markaziy Osiyo mintaqasidagi ikki tomonlama savdo hajmiga savdoni osonlashtirish choralarining ta’sirini baholaydi. Topilmalar O’zbekistonning savdo samaradorligini oshirishda infratuzilmani rivojlantirish, bojxona modernizatsiyasi va mintaqaviy hamkorlikning muhim rolini ta’kidlaydi. Tahlil shuni ko’rsatadiki, savdo-sotiqni osonlashtirish bo’yicha ilg’or chora-tadbirlarga ega mamlakatlar O’zbekiston bilan savdo hajmini oshirmoqda, bu esa transport infratuzilmasiga strategik investitsiyalar va tartibga soluvchi islohotlar muhim ahamiyatga ega ekanligini ko’rsatmoqda. Ushbu sa’y-harakatlar O’zbekistonni jahon bozorlariga yanada samarali integratsiya qilish va mintaqada iqtisodiy o’sishni ta’minlash uchun juda muhimdir.

Ushbu tadqiqot maqolasi turli xil sherikliklarni qamrab olish uchun an’anaviy ittifoqlardan tashqarida kengayadigan yangi asosni taqdim etadi. G’arbiy vektorni geosiyosiy ahamiyati uchun saqlab qolish, cheklangan to’g’ridan-to’g’ri ta’sir bilan bo’lsa ham, ramka Rossiya va Xitoy vektorlarini mintaqaviy chayqalishi tufayli qo’llab-quvvatlaydi. Gcc mamlakatlari kabi mintaqaviy kuchlarni o’z ichiga olgan to’rtinchi vektorni aniqlash muhim ahamiyatga ega. Iqtisodiyoti rivojlanayotgan va yirik davlatlarga nisbatan betaraflikning tarixiy pozitsiyalariga ega bo’lgan ikkinchi darajali davlatlar sifatida tavsiflangan ushbu davlatlar Markaziy Osiyo bilan chuqur iqtisodiy, xavfsizlik va madaniy aloqalarga ega. Xususan, energetika va transport kabi muhim sohalardagi hamkorlik ushbu hamkorlikning ahamiyatini ta’kidlaydi. Maqolada Markaziy Osiyo davlatlarining ushbu rivojlanayotgan davlatlar bilan keng hamkorlik qilish asoslari ko’rib chiqilib, mintaqaning rivojlanayotgan geosiyosiy manzarasi haqida qimmatli tushunchalar berilgan. Tuzilgan tadqiqot orqali qog’oz g’arbiy, rus va Xitoy vektorlari uchun strategiyalarni bayon qiladi, keyinchalik to’rtinchi vektorning paydo bo’lishi va dinamikasiga e’tibor qaratadi. Maqola Markaziy Osiyoning ushbu yangi sheriklar bilan o’zaro munosabatlarini boshqaradigan motivlar va mexanizmlarni sinchkovlik bilan o’rganib chiqib, ushbu rivojlanayotgan munosabatlarga xos bo’lgan murakkabliklar va imkoniyatlarga oydinlik kiritadi. Xulosa asosiy dalillarni sintez qiladi va Markaziy Osiyodagi o’zgaruvchan geosiyosiy dinamikani aniqlash uchun keyingi tadqiqotlar uchun yo’llarni taklif qiladi.

Ayniqsa, O’zbekiston va Germaniya o’rtasida madaniyatlararo aloqa o’rnatishning dolzarbligi ushbu maqolaning asosiy mavzusi hisoblanadi. Maqolada xalqaro miqyosda uyg’un munosabatlarni ta’minlash uchun turli madaniyatlar o’rtasidagi muvaffaqiyatli o’zaro munosabatlarning ahamiyati tahlil qilingan. Madaniy farqlarni hurmat qilish, dunyoqarashini kengaytirish va ko’p madaniyatli muhitda samarali muloqot qilishning ahamiyati muhokama qilinadi.

O’zbekiston va Germaniya munosabatlari sharoitida madaniyatlararo muloqotlar orqali o’zaro tushunish va hamkorlikni takomillashtirish imkoniyatlariga alohida e’tibor qaratilmoqda. Maqola mualliflari turli madaniyatlar va mamlakatlar vakillari o’rtasidagi ijobiy munosabatlarni rivojlantirishga yordam beradigan usul va strategiyalarni tahlil qiladilar. Muvaffaqiyatli madaniyatlararo muloqot xalqaro hamkorlik va nizolarni hal qilish uchun qanchalik muhim ekanligi ushbu tadqiqotda muhokama qilinadi. Ish natijalari

O’zbekiston va Germaniya o’rtasidagi ijobiy munosabatlarni tushunish va rivojlantirish, shuningdek, muvaffaqiyatli madaniyatlararo aloqalarni rivojlantirishga yordam beradigan umumiy standartlar va amaliyotlarni ishlab chiqish uchun foydali bo’lishi mumkin.

В последние годы в список модельных организмов внесен свободноживущий плоский червь Macrostomum lignano, нашедший широкое применение в ряде областей научных изысканий. Его ключевая особенность, высокий потенциал к регенерации, предоставляет ему устойчивость к токсичным соединениям и онкогенам, высокую адаптивность к резким изменениям факторов окружающей среды, а также длительный срок жизни, граничащий с условным бессмертием. С другой стороны, особенности хромосомного состава генома M. lignano, выраженные в ряде геномных нестабильностей, вкупе с регенерацией, не переходящей в опухолевый генез, открывает широкие возможности для фундаментальных исследований противораковых терапий. Обзор посвящен разбору направлений биологических наук, где применяется или мог бы применяться M. lignano.

Xavfsizlik tadqiqotlari konteksti uzoq vaqtdan beri xalqaro siyosatda keng tarqalgan. Zamonaviy xalqaro munosabatlar tarixi Evropada xavfsizlik masalalari bilan bog’liq bo’lgan mustaqil davlatlarning paydo bo’lishi bilan boshlandi. Tarixiy jihatdan Amerika tashqi siyosati amaliyoti xavfsizlik manfaatlariga nisbatan bilim va munosabat nuqtai nazaridan ikkita alohida yo’nalishni, shuningdek, xalqaro siyosatning asosiy muammolariga ikki xil yondashuvni jalb qildi. Amerikalik mutaxassislar tomonidan tashqi siyosat bo’yicha jiddiy tadqiqotlarning asosiy qismi ushbu ikki yondashuvni o’rganishdan boshlanadi.