Annotation. This article shows a method for solving two periodic solutions of second order differential equations with piecewise continuous constant arguments in the form x''(t)+px''(t-1)=qx([t])+f(t ), where [.]denotes the function of the largest integer, p and q are non-zero real numbers, and f(t) is a real-valued periodic function. In the article, firstly, the conditions for the existence of 2-periodic solutions of second-order differential equations are given, and then the solution of the problem is represented as a linear system of algebraic equations
Continuous model of Lotka-Volter’s on simplex Sm-1 is studied in the article. There was determined a
relationship between tournament and the system of differential square equation, that describes
evolution of genetic systems in Lotka-Volter’s model.
This article describes the work carried out to improve the educational system and content of differential diagnosis of children with complex defects, a brief analysis of the educational opportunities of children with complex defects. Information about the work of medical workers and various specialists, educators is also provided.
The article is devoted to the development of a mathematical model of the process of geometric nonlinear deformation of thin magnetoelastic plates of a complex structural shape based on the Hamilton-Ostrogradsky variational principle, and conducting computational experiments. In this case, the three-dimensional mathematical model was transferred to a two-dimensional view using the Kirchhoff-Liav hypothesis. Cauchy's relationship, Hooke's law, Lawrence's force and Maxwell's electromagnetic tensor were used to determine kinetic and potential energy and work done by external forces. The effects of the electromagnetic field on the deformation stress state of the magnetoelastic plate were observed, as a result, a mathematical model was created in the form of a system of differential differential equations with initial and boundary conditions for displacement. To solve the equation, a calculation algorithm was developed using the R-function, Bubnov-Galerkin, Newmark, Gaussian, Gaussian squares, and Iteration number methods. Calculation experiments were carried out in various mechanical states of the magneto-elastic plate, its borders were tightly fixed, one side was hinged and the other side was free, and numerical results were obtained. A comparative analysis of the results of the calculations was presented.
The article discusses with paremas, their features, hypo-hyperonymic relations between parema and its constituent units, integral and differential sign of each unit.
Широко используемым в клинических целях РФП для ПЭТ— диагностики является 18F—фтордезоксиглюкоза (18F — ФДГ— 18F— 2—фтор— 2дезокси—D—глюкоза), более чем в 95% всех ПЭТ—исследований проводятся именно с этим РФП.
Мақолада ер рентаси назарияси, аграр ва ер ислоҳоти жараёни ҳақида шунингдек, ҳозирда хорижий мамлакатлар шу жумладан, МДҲ давлатларининг ер солиғини ундириш тажрибалари, дифференциал рентани шакллантирувчи омиллар бўйича ер солиғи тизимини такомиллаштириш ва унинг аҳамияти, ер солиғининг қишлоқ хўжалигидаги ўрни ва аҳамияти ҳамда ерларнинг норматив қийматини баҳолаш тизимларининг ўзаро боғлиқлиги ва таҳлили, ягона ер солиғининг қишлоқ хўжалиги ерларининг мелиоратив ҳолатини яхшилаш ва тупроқ унумдорлигини оширишдаги ўрни ва ягона ер солиғи тизимидаги маълум камчиликлар ёритиб ўтилган. Изланиш давомида амалдаги ер солиғи тизимини такомиллаштириш масалалари кўриб чиқилган ҳамда улар асосида таклиф ва тавсиялар берилган.
XXI asr - texnologiyalar asri hisoblanadi. Shunday ekan o‘quv jarayonida turli zamonaviy axborot vositalaridan o‘rinli foydalanish, kompyuterli ta’lim jarayonida darslarni o‘quvchi-talaba va kompyuter orasidagi munosabatlarga ko‘ra tashkil etish, boshqarish, nazorat qilish bugungi kunda dolzarb masalalardandir.Tabiiy fanlar hamda texnika fanlarida uchraydigan ko‘pgina masalalar differensial tenglamalarga keltiriladi,ya’ni ularning analitik yechimini topish nihoyatda murakkab masala,shu sababli taqribiy yechish usullaridan foydalanish ko‘proq samara beradi.Bunday muammolarni hal qilish uchun esa matematik paketlar mavjud bo‘lib,ushbu maqolada differensial tenglamalarni Maple dasturida yechish haqida gap boradi.Ya’ni, birinchi tartibli chiziqli oddiy differensial tenglamani Maple dasturida analitik yechimini topish dasturi tuzilib natija olingan.
In gynecological practice, fibroids and adenomyosis are among the most common diseases among women of reproductive age, since these diseases are often the cause of radical operations. Ultrasound examinations are used in the world as screening for the detection of fibroids and adenomyosis. Conducting ultrasound on expert-class devices with blood flow Dopplerometry allows you to differentiate the type of myomatous node, determine the degree of adenomyosis and offer a comprehensive treatment depending on the activity of the process.
Stroke has remained the most important medical and social problem for many years. According to the WHO, of the number of stroke survivors, only half remain functional. Cognitive impairments of varying severity occur in a significant number of patients with acute cerebrovascular accident, and slow down the process of functional recovery, increase the risk of recurrent stroke and death. In the recovery period of a stroke, both regression and a significant increase in cognitive deficit are possible. The prevalence of im -paired cognitive functions in the population associated with vascular diseases of the brain has a significant impact on the state of so - ciety as a whole and is one of the most pressing medical and social problems that cause impaired adaptation in the professional, social and domestic spheres.
In this article, the principles of development of professional competences of future engineers of higher educational institutions by developing project models of training based on a differential approach in practical training in physics are presented. During the practical lessons, the methodical model of building non-linear learning trajectories is explained and systematically described.
Relevance of the problem. The difficulties of diagnostics of orbital diseases are well known. Especially difficult is intraspecies differentiation among the multitude of tumour, pseudotumour, inflammatory, vascular, endocrine and other diseases occurring here, manifested by the symptom complex of unilateral exophthalmos [Beradze I.N., 1978; Brovkina A.F., 1993].
Malignant intraocular neoplasms are the main cause of death of patients with diseases of the organ of vision, with 45-48% of patients dying from metastases in the first 5 years after enucleation [Alekseeva I.B., 1990, Barkhash S.A.1978, Brovkina A.F..1991, 1997; Keizer R.W.. Viclvoyc G.L.,1986],
Retinoblastoma is the most frequent malignant neoplasm in children. According to different authors, the frequency of its occurrence is 1 case per 14000 - 35000 newborns. [Bobrova N.F. and Vit V.V., 1993; Brovkina A.F., 1997; Provenzale J.M., et al., 1995; Skulski M., et al., 1997; Weber A.L., Mafee M.F, 1992; Wilms G., et al., 1989]. The frequency of patients with the most malignant intraocular tumour in adults - uveal melanoma has recently reached 7-9 people per 1 million population [Brovkina A.F., 1997; Kotslyansky E.O., 1989; Yushko N.A., Peskova L.I., Kalenich L.A., 1989; Peyster R.G., Augsburger J..I., Shields J.A., 1988; Romani A.. Baldeschi L., ct al 1998; Scott I.U., 1998].
The fundamental difference in treatment tactics, depending on the stage of development, size and topography of the tumour, as well as the seriousness of the prognosis in retinoblastomas and melanomas sharply increase the requirements for the accuracy of their differential diagnosis. At the same time, the number of diagnostic errors in ocular tumours continues to be 10-30% even when complex clinical and instrumental examination is applied in specialised ophthalmological centres [Ternovoy S.K., Panfilova G.V., Rogozhin V.A., 1979; Friedman F.E., Malyuta G.D., Kodzov M.V., 1995; Song G.X., 1991].
Widely used in ophthalmological practice traditional diagnostic methods (ophthalmoscopy, gonioscopy, diaphanoscopy, fluorescence angiography, laboratory tests) are insufficient to obtain comprehensive information about the localisation, nature of growth and prevalence of volumetric pathological formations of the eye and orbit. This circumstance and not quite satisfactory results of surgical treatment are the causes of high mortality of patients [Muratova T.T., Nigmanova N.H., Kozlovskaya G.M.. 1989, Naches A.I., 1980; Cheremisin V.M., Trufanov G.E., Kholin A.V., 1991]. Untimely or erroneous recognition of pathological processes of the orbit leads to a sharp deterioration of visual functions, up to blindness, and in some cases to the death of the patient [Yuzhakov A.M., Travkin A.G., Kiseleva O.A., 1991]. All this determines the importance of timely and accurate diagnosis of diseases of the orbit, on the one hand, and the difficulty of such diagnosis - on the other [Gabunia R.I., Kolesnikova E.K., Tumanov L.B., 1982].
The fact that the orbit is closed from direct inspection and palpation by bone walls and the eyeball, indicates the advantage of radial diagnostics in comparison with other methods of examination. In the arsenal of clinicians there is a great variety of methods of clinical-radial diagnostics of orbital pathology, however, at present the information in the literature about their resolving capabilities and significance in comparative aspect is incomplete and not fully studied. The priority of using one or another instrumental investigation, their sequence and expedient combination have not been determined yet. This makes it difficult to choose the optimal standardised approach for diagnosis and adequate treatment [Cheremisin V.M., Trufanov G.E., 1993, Weber A.L., Sabates N.R., 1996; Wenig V.M., Mafee M.F., 1998].
Thus, the study of these and other questions, contributing to the improvement of diagnostics and treatment of patients with neoplasms of the eye and ocular cavity, should be recognised as urgent urgent.
Purpose of the study. Comparative evaluation of magnetic resonance tomography capabilities and development of algorithms for complex radial diagnostics of volumetric formations of the visual organ. To solve this goal we set the following tasks.
1. To study the normal picture of the magnetic resonance image of the visual organ in comparison with other methods of visualisation.
2. To find out the possibilities of magnetic resonance tomography, ultrasound and computed tomography in detection and evaluation of intraocular neoplasms.
3. To determine the role and place of magnetic resonance tomography in differential diagnostics of volumetric pathological formations of the eye cavity in comparison with other radial methods of research.
4. To determine the indications and to develop an algorithm for the complex application of radiography, ultrasound, computer and magnetic resonance tomography for diagnostics of volumetric formations of the eye organ.
Scientific novelty.
The present work is the first to give a detailed and detailed description of the complex clinical and radiation examination, with generalisation and standardisation of magnetic resonance, computer and ultrasound semiotics of volumetric pathological formations of the eye and eye cavity. The conducted clinical and instrumental investigations allowed to determine the diagnostic value and resolving capabilities of each of the applied methods. The ultrasound, CT and MRI signs of volumetric formations of the eye organ were studied, clarified and supplemented taking into account the use of low-field magnetic field and general-purpose ultrasound apparatus. The developed standardised diagnostic algorithm of examination of patients with this pathology is new, thanks to which the pre-oppositional diagnosis of tumour and other diseases of the visual organ is improved and the total radiation load on the patient is reduced.
Conclusions
1. MPT will provide an opportunity to study the weight of the soft tissue and anatomical components of the ocular cavity, up to the optic nerve sheath and perineural liquor space, the orbital apex and chiasmal-sellar region, as well as to assess the condition of adjacent structures of the brain and facial skull. The method is limited in the evaluation of changes in the bony walls of the orbital cavity.
2. MRI is inferior in detecting characteristic signs of retinoblastoma (presence of calcification). The sensitivity of MRI was 66.6%, while for ultrasound and CT these values were 96.1 and 100%, respectively. But when the tumour spreads rstrobulbarly outside the eyeball (at 3-4 stages) the informativeness of MRI increases significantly. In uveal melanoma the sensitivity and specificity of MRI reaches 100%.
3. Both MRI and CT have a high detection rate (98.1% and 95.8% respectively) of benign orbital tumours of both primary and secondary origin. However, MRI is the preferred method of investigation. MRI is especially informative when a cranioorbital tumour and pseudotumour are suspected. The sensitivity of the method is 90.9% and 91.6%, respectively
4. In some cases ultrasound can be used to differentiate between encapsulated and diffuse neoplasms, which facilitates the diagnosis. However, when the pathological process is localised near the orbital apex, the diagnostic value of ultrasound decreases. In such cases it is advisable to use MRI.
5. In detection of primary and secondary malignant tumours of the orbital cavity both MRI and CT are quite informative (sensitivity 97,2% and 95,4% respectively), but the most comprehensive information about the state of bone walls will be provided by CT. When the process spreads intracranially, the value of MRI increases significantly, especially with the use of contrast enhancement.
6. The developed algorithm of complex clinical and radiation examination of patients with the use of ultrasound, CT and MRI is the most effective in the diagnosis of volumetric pathological formations of the eye and eye cavity, allowing to reduce to an adequate minimum the total radiation load on the patient and diagnostic period, excluding duplication of research techniques and choosing the most informative in each case, which in turn allows to develop appropriate treatment tactics and reduce the level of disability of the patient.