646 research outputs found
О возможности изучения фотолиза твердых соединений и спектральной сенсибилизации этого процесса
Growth of children with Langerhans cell histiocytosis
Conclusion: GH deficiency is not a common manifestation of LCH in childhood and GH provocation tests are only indicated when there is a poor or decelerating growth rate. In our patients the number of organs involved and/or the treatment modality did not influence the growth in all but one. Diseases in childhood have an impact on growth. The influence of Langerhans cell histiocytosis (LCH) on growth has never been studied well. Recently a patient with LCH was treated with human growth hormone (GH) because of severe GH deficiency due to LCH involvement of both the hypothalamus and pituitary. This led us to review our charts from 1971 onward for evaluation of the growth patterns in patients with LCH. Here the long-term growth of 22 patients with LCH is reported, the median follow up being 7 years and 1 month. The height data were converted into standard deviation scores (SDS). At diagnosis the mean SDS of patients with isolated LCH at diagnosis was 0.04 and -0.37 in patients with disseminated LCH. Of the total group, 12 patients did not show any influence from the LCH or therapy on their growth. The remaining 10 patients reached, after a minimum of 3 years, a percentile clearly higher than that at diagnosis. However all the ten above mentioned patients, either isolated or disseminated LCH, had a lesion in the facial side of the skull
Atmospheric transport and chemistry of trace gases in LMDz5B: evaluation and implications for inverse modelling
Representation of atmospheric transport is a major source of error in the estimation of greenhouse gas sources and sinks by inverse modelling. Here we assess the impact on trace gas mole fractions of the new physical parameterizations recently implemented in the atmospheric global climate model LMDz to improve vertical diffusion, mesoscale mixing by thermal plumes in the planetary boundary layer (PBL), and deep convection in the troposphere. At the same time, the horizontal and vertical resolution of the model used in the inverse system has been increased. The aim of this paper is to evaluate the impact of these developments on the representation of trace gas transport and chemistry, and to anticipate the implications for inversions of greenhouse gas emissions using such an updated model. Comparison of a one-dimensional version of LMDz with large eddy simulations shows that the thermal scheme simulates shallow convective tracer transport in the PBL over land very efficiently, and much better than previous versions of the model. This result is confirmed in three-dimensional simulations, by a much improved reproduction of the radon-222 diurnal cycle. However, the enhanced dynamics of tracer concentrations induces a stronger sensitivity of the new LMDz configuration to external meteorological forcings. At larger scales, the inter-hemispheric exchange is slightly slower when using the new version of the model, bringing them closer to observations. The increase in the vertical resolution (from 19 to 39 layers) significantly improves the representation of stratosphere/troposphere exchange. Furthermore, changes in atmospheric thermodynamic variables, such as temperature, due to changes in the PBL mixing modify chemical reaction rates, which perturb chemical equilibriums of reactive trace gases. One implication of LMDz model developments for future inversions of greenhouse gas emissions is the ability of the updated system to assimilate a larger amount of high-frequency data sampled at high-variability stations. Others implications are discussed at the end of the paper
Исследование динамических характеристик задвижки с электроприводом
В рамках проведенной работы был приведен обзор электроприводов для задвижек, рассмотрены различные виды зубчатых зацеплений. Проанализирована интерференция зубьев циклоидального редуктора.The as part of the work, a review of the electric actuators for the valves was given, various types of gears were considered. The tooth interference of the cycloidal gearbox is analyzed
Patients' and physiotherapists' perspectives on implementing a tailored stratified treatment approach for low back pain in Nigeria: a qualitative study
Background: Stratified care has the potential to be efficient in addressing the physical and psychosocial components of low back pain (LBP) and optimise treatment outcomes essential in low-income countries. This study aimed to investigate the perceptions of physiotherapists and patients in Nigeria towards stratified care for the treatment of LBP, exploring barriers and enablers to implementation. Methods: A qualitative design with semistructured individual telephone interviews for physiotherapists and patients with LBP comprising research evidence and information on stratified care was adopted. Preceding the interviews, patients completed the Subgroups for Targeted Treatment tool. The interviews were recorded, transcribed and analysed following grounded theory methodology. Results: Twelve physiotherapists and 13 patients with LBP participated in the study (11 female, mean age 42.8 (SD 11.47) years). Seven key categories emerged: recognising the need for change, acceptance of innovation, resistance to change, adapting practice, patient's learning journey, trusting the therapist and needing conviction. Physiotherapists perceived stratified care to be a familiar approach based on their background training. The prevalent treatment tradition and the patient expectations were seen as major barriers to implementation of stratified care by the physiotherapists. Patients see themselves as more informed than therapists realise, yet they need conviction through communication and education to cooperate with their therapist using this approach. Viable facilitators were also identified as patients' trust in the physiotherapist and adaptations in terms of training and modification of the approach to enhance its use. Conclusion: Key barriers identified are the patients' treatment expectations and physiotherapists' adherence to the tradition of practice. Physiotherapists might facilitate implementation of the stratified care by communication, hierarchical implementation and utilisation of patients' trust. Possibilities to develop a consensus on key strategies to overcome barriers and on utilisation of facilitators should be tested in future research
The prognosis of oncologic patients in the pediatric intensive care unit
Objective: To evaluate the predicted mortality rate of oncologic patients in the PICU using the PRISM score and factors that might influence short-term outcomes. Design: Retrospective study. Setting: Pedriatic ICU in a university hospital. Patients and Methods: The medical charts of all oncologic patients admitted to the PICU during the period from January 1983 to December 1992 were reviewed. Main Results: Over a period of 10 years, 51 oncologic patients were admitted on 57 occasions to the PICU. The mortality was 32%. This is significantly higher than the overall mortality in the PICU (8%). Comparison of observed and predicted mortality, derived from the PRISM score, using chi square goodness-of-fit tests showed a significantly higher observed mortality (χ2(5) = 20.1, P < 0.01). Patients admitted for circulatory failure had the highest mortality (47%), followed by those with respiratory failure due to tachypnea/cyanosis (36%), central nervous system deterioration (27%), respiratory failure due to airway obstruction (25%), and metabolic disorders (20%). Of the 31 patients who needed mechanical ventilation, 17 died (55%), and when they needed inotropic support as well, the mortality increased to 69%. The mortality rose to 100% when the patient was admitted with a septic shock, necessitating mechanical ventilation and inotropic support. The median PRISM score was 5 in the survivor group and 18.5 in the non-survivor group; this difference was found to be significant using the Wilcoxon test (P = 0.01). However, some patients with high scores were found in the survivor group, as well as some with low scores in the non-survivor group. Conclusion: The decision to treat oncologic patients in a PICU remains difficult and has to be considered on an individual basis. However, oncologic patients do benefit from admission to the PICU. The PRISM score is not suitable for oncologic patients in the PICU, because it underestimates the observed mortality. Other factors like neutropenia, septic shock, the need for mechanical ventilation, and inotropic support should be taken into consideration
Технологии нанесения изоляционных покрытий при капитальном ремонте магистрального нефтепровода «Александровское-Анжеро-Судженск»
Объектом исследования является (ются) магистральный нефтепровод «Александров-ское – Анжеро – Судженск» км 440 – 441.
Цель работы – Выявление оптимальных технологий нанесения изоляционных покрытий в трассовых условиях, участка линейной части магистрального нефтепровода «Александров-ское - Анжеро – Судженск» км 440 – 441, проложенного по заболоченной местности.
В процессе исследования проводились Анализ переходного сопративления нефтепро-вода, расчет срока службы остаточного ресурсThe object of this study is (are) the main oil pipeline "Alexandrov - Anzhero - Sudzhensk" km 440 - 441.
Objective - Identify optimal insulation coating technologies in the field conditions, the linear portion of the main oil pipeline "Alexandrov - Anzhero - Sudzhensk" km 440 - 441, laid on marshland
The study carried out analysis of the transition soprativleniya pipeline calculation lifetime residual life of the insulating coating of the pipeline operated. The problems of insulation coating technologies. Presents measures for health and safety of the work, environmental protection, technical and economic part.
The study was carried out a comparative analysis of transition soprativleniya pipeline in time. Based on these results, it was found that the use of insulation. "Transkor" Litkor - Tax Code has a number of advantages, one of which is to increase the life of the pipeline.
The basic constructive, technological and technical and operational characteristics: Technology and organization of works and preparatory works, earthworks, insulating - styling work.
Degree of implementation: On osnovonaii studies it was concluded that the needed overhaul with the replacement of the insulation portion of the current main oil pipeline "Alexandrov - Anzhero - Sudzhensk» 440-441 km.
Scope: Main oil pipeline "Alexandrov - Anzhero - Sudzhensk 440-441 km, Tomsk region.
Cost-effectiveness / value of the work effort with insulation coating during overhaul of the pipeline mechanized method is less than with manual application
The Hidden Giant: How a rift pulse triggered a cascade of sector collapses and voluminous secondary mass‐transport events in the early evolution of Santorini
Volcanic island sector collapses have the potential to trigger devastating tsunamis and volcanic eruptions that threaten coastal communities and infrastructure. Considered one of the most hazardous volcano-tectonic regions in the world, the Christiana-Santorini-Kolumbo Volcanic Field (CSKVF) lies in the South Aegean Sea in an active rift zone. Previous studies identified an enigmatic voluminous mass-transport deposit west and east of Santorini emplaced during the early evolution of the edifice. However, the distribution and volume as well as the nature and emplacement dynamics of this deposit remained unknown up to now. In this study, we use an extensive dataset of high-resolution seismic profiles to unravel the distribution and internal architecture of this deposit. We show that it is located in all basins surrounding Santorini and has a bulk volume of up to 125 km3, thus representing the largest known volcanic island mass-transport deposit in the entire Mediterranean Sea. We propose that the deposit is the result of a complex geohazard cascade that was initiated by an intensive rift pulse. This rifting event triggered a series of smaller precursory mass-transport events before large-scale sector collapses occurred on the northeastern flank of the extinct Christiana Volcano and on the southeastern flank of the nascent Santorini. This was followed by the emplacement of large-scale secondary sediment failures on the slopes of Santorini, which transitioned into debris and turbidity flows that traveled far into the neighboring rift basins. Following this cascade, a distinct change in the volcanic behavior of the CSKVF occurred, suggesting a close relationship between crustal extension, mass transport, and volcanism. Cascading geohazards seem to be more common in the evolution of marine volcanic systems than previously appreciated. Wider awareness and a better understanding of cascading effects are crucial for more holistic hazard assessments
Pockmarks in the Witch Ground Basin, central north sea
Marine sediments host large amounts of methane (CH4), which is a potent greenhouse gas. Quantitative estimates for methane release from marine sediments are scarce, and a poorly constrained temporal variability leads to large uncertainties in methane emission scenarios. Here, we use 2‐D and 3‐D seismic reflection, multibeam bathymetric, geochemical, and sedimentological data to (I) map and describe pockmarks in the Witch Ground Basin (central North Sea), (II) characterize associated sedimentological and fluid migration structures, and (III) analyze the related methane release. More than 1,500 pockmarks of two distinct morphological classes spread over an area of 225 km2. The two classes form independently from another and are corresponding to at least two different sources of fluids. Class 1 pockmarks are large in size (>6 m deep, >250 m long, and >75 m wide), show active venting, and are located above vertical fluid conduits that hydraulically connect the seafloor with deep methane sources. Class 2 pockmarks, which comprise 99.5% of all pockmarks, are smaller (0.9–3.1 m deep, 26–140 m long, and 14–57 m wide) and are limited to the soft, fine‐grained sediments of the Witch Ground Formation and possibly sourced by compaction‐related dewatering. Buried pockmarks within the Witch Ground Formation document distinct phases of pockmark formation, likely triggered by external forces related to environmental changes after deglaciation. Thus, greenhouse gas emissions from pockmark fields cannot be based on pockmark numbers and present‐day fluxes but require an analysis of the pockmark forming processes through geological time
Greenhouse gas observation network design for Africa
An optimal network design was carried out to prioritise the installation or refurbishment of greenhouse gas (GHG) monitoring stations around Africa. The network was optimised to reduce the uncertainty in emissions across three of the most important GHGs: CO2, CH4, and N2O. Optimal networks were derived using incremental optimisation of the percentage uncertainty reduction achieved by a Gaussian Bayesian atmospheric inversion. The solution for CO2 was driven by seasonality in net primary productivity. The solution for N2O was driven by activity in a small number of soil flux hotspots. The optimal solution for CH4 was consistent over different seasons. All solutions for CO2 and N2O placed sites in central Africa at places such as Kisangani, Kinshasa and Bunia (Democratic Republic of Congo), Dundo and Lubango (Angola), Zoétélé (Cameroon), Am Timan (Chad), and En Nahud (Sudan). Many of these sites appeared in the CH4 solutions, but with a few sites in southern Africa as well, such as Amersfoort (South Africa). The multi-species optimal network design solutions tended to have sites more evenly spread-out, but concentrated the placement of new tall-tower stations in Africa between 10ºN and 25ºS. The uncertainty reduction achieved by the multi-species network of twelve stations reached 47.8% for CO2, 34.3% for CH4, and 32.5% for N2O. The gains in uncertainty reduction diminished as stations were added to the solution, with an expected maximum of less than 60%. A reduction in the absolute uncertainty in African GHG emissions requires these additional measurement stations, as well as additional constraint from an integrated GHG observatory and a reduction in uncertainty in the prior biogenic fluxes in tropical Africa
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