با سلام خدمت کاربران عزیز، به اطلاع می رساند ترجمه مقالاتی که سال انتشار آن ها زیر 2008 می باشد رایگان بوده و میتوانید با وارد شدن در صفحه جزییات مقاله به رایگان ترجمه را دانلود نمایید.
Ecological and environmental consequences of ecological projects in the Beijing–Tianjin sand source region
پیامدهای محیطی و زیست محیطی از پروژه های زیست محیطی در منطقه منبع شن و ماسه پکن - تیانجین-2020
Evaluation of influences of the Beijing–Tianjin Sand Source Control Project on soil wind erosion and ecosystem services is imperative for mastering the benefits and drawbacks of the program, as well as for distinguishing more reasonable estimations to evaluate regional sustainable development. Within the Beijing–Tianjin Sand Source Region, we quantified the spatiotemporal patterns of land use/cover changes (LUCCs), soil wind erosion modulus (SWEM), and essential ecosystem services throughout 2000–2015 by utilizing field investigations, remotely sensed data, meteorological data, and modeling. The influences of ecological projects on wind erosion and ecosystem services has been subsequently assessed by using those modifications brought on via the LUCCs (e.g., conversion from cropland to grassland/woodland) during the ecological construction. The results indicated that the SWEM showed a decline and ecosystem services which included carbon storage, water retention, and air quality regulation exhibited growth driven by using both local climate exchanges and human activities such as ecological projects. Excluding the effects of climate factors, the LUCCs stemming from ecological projects caused a total SWEM decrease of 3.77 million tons during 2000–2015, of which approximately 70% was prompted by the way of the transition from desert to sparse grassland. And from this transition, ecosystem services including both water retention and aboveground net primary productivity manifest a general increase. The sub-regions of desert grassland in Bayannur, Ordos Sandy Land, and Otindag Sandy Land were hot spots for wind erosion declines and ecosystem service enhancements induced by the ecological projects. We recommend that endeavors be coordinated toward the scientific management of the degraded lands and distribution of the local populace, as well as the implementation of diverse measures in the expected hotter and drier future.
Keywords: Wind erosion Ecosystem services | Sustainability | Spatiotemporal pattern | Land use/cover change | Ecological project
Identifying mutation positions in all segments of influenza genome enables better differentiation between pandemic and seasonal strains
شناسايي موقعيت جهش در تمامي بخش هاي ژنوم آنفلوانزا باعث تمايز بهتر ميان سويه ها و بيماري هاي فصلي مي شود-2019
Influenza has a negative sense, single-stranded, and segmented RNA. In the context of pandemic influenza research, most studies have focused on variations in the surface proteins (Hemagglutinin and Neuraminidase). However, new findings suggest that all internal and external proteins of influenza viruses can contribute in pandemic emergence, pathogenicity and increasing host range. The occurrence of the 2009 influenza pandemic and the availability of many external and internal segments of pandemic and non-pandemic sequences offer a unique opportunity to evaluate the performance of machine learning models in discrimination of pandemic from seasonal sequences using mutation positions in all segments. In this study, we hypothesized that identifying mutation positions in all segments (proteins) encoded by the influenza genome would enable pandemic and seasonal strains to be more reliably distinguished. In a large scale study, we applied a range of data mining techniques to all segments of influenza for rule discovery and discrimination of pandemic from seasonal strains. CBA (classification based on association rule mining), Ripper and Decision tree algorithms were utilized to extract association rules among mutations. CBA outperformed the other models. Our approach could discriminate pandemic sequences from seasonal ones with more than 95% accuracy for PA and NP, 99.33% accuracy for NA and 100% accuracy, precision, specificity and sensitivity (recall) for M1, M2, PB1, NS1, and NS2. The values of precision, specificity, and sensitivity were more than 90% for other segments except PB2. If sequences of all segments of one strain were available, the accuracy of discrimination of pandemic strains was 100%. General rules extracted by rule base classification approaches, such as M1-V147I, NP-N334H, NS1-V112I, and PB1-L364I, were able to detect pandemic sequences with high accuracy. We observed that mutations on internal proteins of influenza can contribute in distinguishing the pandemic viruses, similar to the external ones.
Keywords: Association rule mining | CBA | Expert system | Hot spots | Ripper algorithm | Pandemic influenza
Causal Analysis of Airline Trajectory Preferences to Improve Airspace Capacity
تحلیل علل ترجیحات مسیریابی خطوط هوایی برای بهبود ظرفیت هوایی-2017
The problem of fitting the maximum number of aircraft into ATC sectors, keeping in mind aircraft separation and safety standards, area navigation direct routings and other factors, is known as the airspace capacity problem. Above the European airspace, a high density network of air traffic can be found which is determined by the workload of controllers. Constraint Programming (CP) is a powerful powerful paradigm for representing and solving a wide range of combinatorial problems. The PARTAKE project fosters adherence of air space user’s trajectory preferences enhancing Trajectory Based Operations (TBO) concepts by identifying tight interdependencies between trajectories and introducing a new mechanism to improve aircraft separation at the hot spots by the mean of CP. The underlying philosophy is to capitalize present freedom degrees between layered ATM planning tools, when sequencing departures at airports by considering the benefits of small time stamp changes in the assigned slot departures.
Keywords: Air traffic management | Trajectory Based Operations | Decision Support Tool | Airspace capacity
Engine hot spots: Modes of auto-ignition and reaction propagation
نقاط داغ موتور: حالت خودکار سیستم جرقه زنی و انتشار واکنش-2016
Article history:Received 15 August 2015Revised 4 January 2016Accepted 5 January 2016Available online 6 February 2016Keywords:Ignition delay time Excitation time Hot spotsDetonation peninsula Auto-ignitive propagation Super-knockMany direct numerical simulations of spherical hot spot auto-ignitions, with different fuels, have identi- ﬁed different auto-ignitive regimes. These range from benign auto-ignition, with pressure waves of small amplitude, to super-knock with the generation of damaging over-pressures. Results of such simulations are generalised diagrammatically, by plotting boundary values of ξ , the ratio of acoustic to auto-ignition velocity, against ε. This latter parameter is the residence time of the developing acoustic wave in the hot spot of radius ro , namely ro /a, normalised by the excitation time for the chemical heat release, τe . This ratio controls the energy transfer into the developing acoustic front. A third relevant parameter involves the product of the activation temperature, E/R, for the auto-ignition delay time, τi , normalised by the mixture temperature. T, the ratio, τi /τe , and the dimensionless hot spot temperature gradient, (∂ ln T /∂r¯), where r¯ is a dimensionless radius. These parameters deﬁne the boundaries of regimes of thermal ex- plosion, subsonic auto-ignition, developing detonations, and non-auto-ignitive deﬂagrations, in plots of ξ against ε.The regime of developing detonation forms a peninsula and contours, throughout the ﬁeld. The product parameter (E/RT )(τi /τe )/∂ ln T /∂r¯ expresses the inﬂuences of hot spot temperature gradient and fuel characteristics, and a unique value of it might serve as a boundary between auto-ignitive and deﬂagrative regimes. Other combustion regimes can also be identiﬁed, including a mixed regime of both auto-ignitive and “normal” deﬂagrative burning. The paper explores the performances of a number of different engines in the regimes of controlled auto-ignition, normal combustion, combustion with mild knock and, ultimately, super-knock. The possible origins of hot spots are discussed and it is shown that the dissipation of turbulent energy alone is unlikely to lead directly to suﬃciently energetic hot pots. The knocking characterisation of fuels also is discussed.© 2016 The Combustion Institute. Published by Elsevier Inc. All rights reserved.