How to scrutinise a Production Sharing Agreement: A guide for the oil and gas sector based on experience from the Caspian region

This guide discusses the provisions of a particular type of oil and gas contract, the Production Sharing Agreement (PSA). While the guide is aimed at a general civil society readership, it draws particularly on experience from Kazakhstan. The purpose of this guide is to give an accessible account of some key characteristics of PSAs, with a focus on revenue issues, and to suggest action points for civil society organisations involved with monitoring extractive industries. Indeed, in recent years the public in resource-rich states has become increasingly concerned about the management of extractive industry revenues

Algorithm for Endovascular Treatment of Patients With Spinal Arteriovenous Malformations

Objective: To compare the endovascular treatment results in patients with spinal arteriovenous malformations (AVM) based on the proposed algorithm.   Materials and methods: We retrospectively analyzed the endovascular treatment results in 72 patients with various types of spinal AVMs for 2014-2021. We formed 2 main groups of patients based on the developed indications for neurophysiological monitoring and provocative tests (NFM and PT): group 1 (n = 63) was treated according to the algorithm, and group 2 (n = 9) was treated before the algorithm was implemented. Group 1 was divided into subgroup 1.1 (n = 42) including patients with no indications for NFM and PT and subgroup 1.2 (n = 21) with patients indicated for NFM and PT. Subgroup 1.2 was further divided into subsubgroup 1.2A (n = 2) with patients indicated for NFM and PT yet to be informative due to severe neurological deficit and subsubgroup 1.2B (n = 19) with patients that had indications for and successfully underwent NFM and PT. We compared patients between groups 1 and 2, subsubgroup 1.2B and group 2 to evaluate the effectiveness of the algorithm (radical nature of the treatment, functional status assessment, complications).   Results: Radical nature of spinal AVM treatment in group 1 was 79 % compared with 44 % in group 2 (P = 0.043). There was a significant improvement in motor function in group 1 compared with group 2 in each follow-up period (Р ≤ 0.007). Comparison of subsubgroup 1.2B and group 2 showed no significant differences (P = .05). The treatment led to complications in 5 patients (7 % of the total number of patients with spinal AVMs): 4 patients in group 2 and 1 patient in subsubgroup 1.2B. The effectiveness of the developed criteria was indirectly confirmed by difference in complications number between subsubgroup 1.2B and group 2 (P = 0.001).   Conclusions: Group 1 showed better treatment results, significant clinical improvement, high radical nature of treatment, and a low percentage of complications compared with group 2. The proposed algorithm proved effective for main tasks of endovascular treatment of spinal AVMs

Development of invasive EEG in epilepsy surgery (review)

There are different diagnostic methods that used for localization of the seizure onset zone in focal refractory epilepsy cases. Invasive video-EEG recording is the «gold standard» in determining the epileptogenic zone among other diagnostic methods. Invasive EEG already has a long history of using. This article provides historical review and analysis of the techniques, their advantages and disadvantages, current issues

Complex-Radical Terpolymerization of Maleic Anhydride (Styrene), Allyl Propionate and Methyl Methacrylate

The radical terpolymerization reactions of the acceptor-donor-acceptor and donor-acceptor-donor systems, maleic anhydride (MA)-allyl propionate (AP)-methyl methacrylate (MMA) and styrene (St)-MMA-AP, had been studied. The terpolymerizations were carried out in methyl ethyl ketone at 60-75 °C in the presence of 2,2’-azoisobutyronitrile (ABIN) used as the initiator. Some kinetic parameters and copolymerization constants - for both, system were determined by dilatometric and Kelen-Tudos or Seiner-Lift methods. The obtained results are discussed in terms of the free monomer and complex chain growth models. It is shown that terpolymerization was carried out at a stage close to binary copolymerization of MA...AP complex with free MMA and St...MMA complex with AP in the both studied system, respectively. These systems are also used as model for interpretation of cyclocopolymerization mechanism in allyl methactylate-MA (or St) system. DTA and TGA analyses indicated the relatively high thermal stability of St-MMA-AP terpolymer. It is shown that this terpolymer decomposes through a one-step reaction at 310 °C, however MA-AP-MMA terpolymer decomposes through a multi-step reactions at 150, 260 and 310 °C

Doppler confirmation of TESS planet candidate TOI1408.01: grazing transit and likely eccentric orbit

We report an independent Doppler confirmation of the TESS planet candidate orbiting an F-type main sequence star TOI-1408 located 140 pc away. We present a set of radial velocities obtained with a high-resolution fiber-optic spectrograph FFOREST mounted at the SAO RAS 6-m telescope (BTA-6). Our self-consistent analysis of these Doppler data and TESS photometry suggests a grazing transit such that the planet obscures its host star by only a portion of the visible disc. Because of this degeneracy, the radius of TOI-1408.01 appears ill-determined with lower limit about $\sim$1 R$_{\rm Jup}$, significantly larger than in the current TESS solution. We also derive the planet mass of $1.69\pm0.20$~$M_{\rm Jup}$ and the orbital period $\sim4.425$ days, thus making this object a typical hot Jupiter, but with a significant orbital eccentricity of $0.259\pm0.026$. Our solution may suggest the planet is likely to experience a high tidal eccentricity migration at the stage of intense orbital rounding, or may indicate possible presence of other unseen companions in the system, yet to be detected.Comment: 5 pages, 3 figure

Search for signatures of reflected light from the exoplanet HD 189733b by the method of residual dynamical spectra

© 2015, Pleiades Publishing, Ltd. The goal of the present study is the development and testing of a method for spectral detection of the light of host stars reflected from their exoplanets. The presented method is based on the analysis of dynamical spectra, which make it possible to obtain high signal-to-noise residual spectra after host star spectrum deduction. These residual spectra contain information on the light reflected from an exoplanet and on its albedo. The first results of such research for the exoplanet HD 189733b are presented in the paper. We obtained a series of a few dozens moderate-resolution spectra of the host star HD 189733. Individual spectra have a high signal-to-noise ratio (≈700) and cover a considerable part of the complete orbital cycle of the exoplanet. The use of the developed method allowed us to achieve a characteristic contrast of the reflected light detection at a level of 5 × 10−4 from the continuum. Investigation of the dynamic spectra with this characteristic value as a detection threshold has not revealed obvious evidence of the host star light reflected from the planet. Nevertheless, the obtained threshold is high, which demonstrates the necessity of the development of the method for the exoplanet monitoring studies

Analysis of cranioplasty procedures performed in Novosibirsk from 2016 to 2022

Background: Studies on reconstructive neurosurgical interventions are always relevant due to the persistence of cranial defects, mainly caused by traumatic brain injuries (TBI). To provide medical care to the patients with cranial defects more efficiently, it is necessary to assess a large number of surgical interventions in studies.Objective: To analyze data on reconstructive neurosurgical interventions performed at Novosibirsk hospitals.Methods: We performed a multicenter observational retrospective non-randomized study of the total cranioplasty surgical interventions from 2016 to 2022. The study involved five neurosurgical departments in Novosibirsk hospitals. In 450 of 673 cases the inclusion criteria were met.Results: The majority of patients (n = 361; 80.2%) underwent surgical interventions in federal health facilities. Urban residents prevailed (n = 260) among the patients who met the inclusion criteria. Craniectomies were mainly indicated for the consequences of TBI (n = 319; 70.9%). Time to cranioplasty ranged from 0.1 to 320 months (mean: 23.9 ± 39.2; median: 11.6 months). There were non-clinically significant differences in terms of primary and reconstructive operations between the defects caused by TBI and other conditions. In 51.1% of cases, we found two features describing the size and complexity of the skull defect. In 19.3% of cases, patients were diagnosed with a skull defect (affected anatomical areas were specified).Conclusions: Over seven years, 450 Novosibirsk residents underwent cranioplasty in five neurosurgical Novosibirsk hospitals (mean: 64.3 surgical interventions a year). Comparing the recent results with previous studies data in terms of performed craniectomies, we found that reconstructive interventions are lacking 99.7 cases per year. To reduce the time to cranioplasty, it is necessary to make a registry of patients with skull defects

ВАЗОНЕВРАЛЬНАЯ КОМПРЕССИЯ: СООТНОШЕНИЯ СОСУДА И REZ У ПАЦИЕНТОВ С ТРИГЕМИНАЛЬНОЙ НЕВРАЛГИЕЙ

Trigeminal neuralgia in most cases caused by compression of trigeminal nerve or its branches with vessels. Compression may locate in root entry zone (REZ) or in a distance from it. The aim of the study is to compare distances from REZ of trigeminal nerve to offending vessel on the symptomatic side to distance to the same vessel on asymptomatic side. Comparing this distances showed significantly shorter distance on symptomatic side. Thus, it could be concluded that this factor has its part in development of trigeminal neuralgia.Тригеминальная невралгия чаще всего вызывается компрессией тройничного нерва или его ветвей сосудистыми структурами. Компрессия может происходить как в зоне выхода корешка из ствола, так называемой root entry zone (REZ), так и на его протяжении. Целью данного исследования является сравнение расстояния от выходной зоны нервного корешка 5-го нерва до «виновного» сосуда в сравнении с аналогичным параметром асимптомной стороны. При сравнении этих показателей расстояние на симптомной стороне было меньше, чем на асимптомной. Это позволяет сделать вывод о влиянии данного фактора на развитие тригеминальной невралгии

ИЗМЕНЕНИЯ МОЗГОВОЙ ПЕРФУЗИИ ПРИ ЭКСТРА-ИНТРАКРАНИ-АЛЬНОМ МИКРОАНАСТОМОЗЕ ПРИ ХРОНИЧЕСКОЙ ОККЛЮЗИИ ВНУТРЕННЕЙ СОННОЙ АРТЕРИИ

Chronic occlusion of internal carotid artery is one of leading reason for brain ischemia. For treating of chronic ICA occlusion EC/IC bypass is used. Aim of the study was to estimate changes of brain perfusion before and after EC/IC bypass. After operation estimation performed in three days. In patients with reduced CBV before EC/IC bypass, there were significant changes of perfusion after operation. For patients with without significant differences of CBV between brain hemispheres changes were not reliable. According to this findings indications for EC/IC bypass must be limited and patients should undergo operation only if it proposed to be effective.Хроническая окклюзия внутренней сонной артерии - одна из ведущих причин ишемии головного мозга. Для лечения хронической ишемии головного мозга применяется экстра-интракраниальный микроанастомоз. Целью данного исследования являлась оценка перфузионной картины головного мозга до и после оперативного лечения. Оценка перфузии головного мозга проводилась на третьи сутки после оперативного лечения. У пациентов без значимой разницы показателя мозгового кровенаполнения между артериальными бассейнами полушарий изменения не были достоверными. Показания к наложению экстра-интракраниального микроанастомоза должны быть четко ограничены и отбор пациентов на оперативное лечение должен производиться исходя из того, что оно будет эффективно