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How does the stand structure of treeline-forming species shape the treeline ecotone in different regions of the Nepal Himalayas?

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Journal of Mountain Science 2020年第10期17卷 2354-2368页

作者： parveen k.chhetri Raju BISTA krishna B.SHRESTHA Department of Earth Science and Geography California State UniversityDominguez HillsCarsonCalifornia90747USA Department of Biological Sciences University of BergenPO Box 7803N-5020BergenNorway

Stand structure dynamics are considered as major happenings in any forest as a response to environmental ***,this important topic is underrepresented in the treeline studies in the Nepal *** aimed to investigate site-as well as species-specific changes in morphometric features(basal diameter,crown cover,density,and height)along the elevational gradient across treeline ecotones in response to recent environmental *** stand structure characteristics of Abies spectabilis,Pinus wallichiana,and Betula utilis across the treeline ecotone of three study sites in Eastern(Barun),Central(Manang),and Western(Dhorpatan)Nepal were analyzed to elucidate structural ***,eight transects(20 m×(60–250 m))across the treeline ecotone were *** of all life forms,trees(>2 m),saplings(0.5–2 m),and seedlings(kes,in further studies,the incorporation of the tree’s morphometric adaptation traits,phenotypic plasticity,and interactions between species genotype and the environment.

关键词： Climate change Morphometry Nepal Himalayas Stand structure Treeline Tree-rings

Topography and human disturbances are major controlling factors in treeline pattern at Barun and Manang area in the Nepal Himalaya

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Journal of Mountain Science 2017年第1期14卷 119-127页

作者： parveen k.chhetri krishna B.SHRESTHA David M.CAIRNS Department of Geography Texas A&M University College Station TX 77840 USA UiB Global Jekteviksbakken 31 PO Box 7800 5020 Bergen Norway

The alpine treeline ecotone is an important component of mountain ecosystems of the Nepal Himalaya; it plays a vital role in the livelihood of indigenous people,and provides ecosystem services. However,the region faces a problem of paucity of data on treeline characteristics at the regional and landscape scales. Therefore,we used Remote Sensing(RS),and Geographic Information Science(GIS) approaches to investigate cross-scale interactions in the treeline ecotone. Additionally,European Space Agency land cover map,International Center for Integrated Mountain Development(ICIMOD) land cover map,ecological map of Nepal,and United States Geological Survey Shuttle Radar Topography Mission-Digital Elevation Model were used to analyze treeline pattern at the regional scale. Digital Globe high-resolution satellite imagery of Barun(eastern Nepal) and Manang(central Nepal) were used to study treeline patterns at the landscape scale. Treeline elevation ranges from 3300-4300 m above sea level. Abies spectabilis,Betula utilis,and Pinus wallichiana are the main treeline-forming species in the Nepal Himalaya. There is an east to west treeline elevationgradient at the regional scale. No slope exposure is observed at the regional scale; however,at the landscape scale,slope exposure is present only in a disturbed area(Manang). Topography and human disturbance are the main treeline controlling factor in Barun and Manang respectively.

关键词： Alpine Treeline Mountain ecosystem Himalaya Remote Sensing(RS) Geographic Information Science(GIS)

Predicting upslope expansion of sub-alpine forest in the Makalu Barun National Park, Eastern Nepal, with a hybrid cartographic model

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Journal of Forestry Research 2018年第1期29卷 129-137页

作者： parveen kumar chhetri Department of Geography Texas A&M UniversityCollege Station

The natural upper boundary of a forest（forest line） in mountain environments is an indicator of climate conditions. An increase in global average temperatures has resulted in an upward advance of the forest line. This advance may result in fragmentation of the alpine ecosystem and a loss of biodiversity. Therefore, it is important to identify potential areas where current forests can advance under scenarios of future climate change. I used expert knowledge and cartographic modeling to create a hybrid cartographic model considering five topographic variables to predict areas where forest line can expand in the *** prediction accuracy of the model is around 82%. The model is able to predict areas above the current forest line that are suitable or unsuitable for future forest *** inclusion of high-resolution satellite imagery and digital elevation models, as well as field-based information into the model can help to improve the model accuracy.

关键词： Climate change Forest line Forest line advance Hybrid cartographic model Makalu Barun National Park

Contemporary and Historic Population Structure of Abies spectabilis at Treeline in Barun Valley,Eastern Nepal Himalaya

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Journal of Mountain Science 2015年第3期12卷 558-570页

作者： parveen kumar chhetri David M.CAIRNS Department of Geography Texas A&M UniversityCollege Station

Treeline ecotone dynamics of Abies spectabilis （D. Don） Mirb. in the Barun valley, Makalu Barun National Park, eastern Nepal Himalaya were studied by establishing seven plots （20 m x variable length） from the foresfline to the tree species limit： three plots on the south- and north-facing slopes each （S1-S3, N1-N3）, and one plot on the east- facing slope （E） in the relatively undisturbed forests. A dendroecological method was used to study treeline advance rate and recruitment pattern. In all the plots, most trees established in the early 20th century, and establishment in the second half of the 20th century was confined to the foresfline area. Treeline position has not advanced substantially in the Barun valley, with 0nly 22 m average elevational shift in the last 13o years, and with average current shifting rate of 14 cm/yr. Moreover, no significant relationship was found between tree age and elevation on the south-, north-, and east-facing slopes. The number of seedlings and saplings in near the treeline area was negligible compared to that near the foresfline area. Therefore, A. spectabilis treeline response to the temperature change was slow, despite the increasing temperature trend in the region. Beside the temperature change, factors such as high inter-annual variability in temperature, dense shrub cover, and local topography also play an important role in treeline advance and controlling recruitment pattern above the treeline.

关键词： Climate change Treeline ecotone Treeline advance Recruitment pattern

Dendroclimatic response of Abies spectabilis at treeline ecotone of Barun Valley, eastern Nepal Himalaya

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Journal of Forestry Research 2016年第5期27卷 1163-1170页

作者： parveen kumar chhetri David M.Cairns Department of Geography Texas A&M UniversityCollege StationTX 77843-3147USA

A dendroclimatic study was conducted in the treeline ecotone of Barun Valley, eastern Nepal, to determine the tree-ring climate response and ring width trend of Abies spectabilis. A 160-year-old chronology, from 1850 to 2010, was developed from 38 tree-ring samples. No higher growth in recent decades was observed in tree-ring width in this area. The mean temperature of the current year in February and in the combined winter months of December, January, and February showed significant positive correlation with tree-ring width, although no significant correlation was found between tree-ring width and the precipitation pattern of the region. This tree-ring climate response result is different from that in other studies in Nepal, which could be attributed to location and elevation.

关键词： spectabilis Dendroclimatology Treeline ecotone Abies Climate response Tree-ring width

Newly Design Porous/Sponge Red Phosphorus@Graphene and Highly Conductive Ni2P Electrode for Asymmetric Solid State Supercapacitive Device With Excellent Performance

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Nano-Micro Letters 2020年第2期12卷 169-184页

作者： Nazish parveen Muhammad Hilal Jeong In Han Department of Chemistry College of ScienceKing Faisal UniversityAl‑Ahsa 31982Saudi Arabia Flexible Display and Printed Electronic Lab Department of Chemical and Biochemical EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

Supercapacitors have attracted much attention in the field of electrochemical energy ***,material preparation,stability,performance as well as power density limit their applications in many ***,a sponge-like red phosphorus@graphene(rP@rGO)negative electrode and a Ni2P positive electrode were prepared using a simple one-step *** electrodes showed excellent performances(294 F g^−1 and 1526.6 F g^−1 for rP@rGO and Ni2P,respectively),which seem to be the highest among all rP@rGO-and Ni2P-based electrodes reported so *** asymmetric solid-state supercapacitor was assembled by sandwiching a gel electrolyte-soaked cellulose paper between rP@rGO and Ni2P as the negative and positive *** to other asymmetric devices,the device,which attained a high operating window of up to 1.6 V,showed high energy and power density values of 41.66 and 1200 W kg−1,*** also has an excellent cyclic stability up to 88%after various consecutive charge/discharge ***,the device could power commercial light emitting diodes and fans for 30 ***,the ease of the synthesis method and excellent performance of the prepared electrode materials mat have significant potential for energy storage applications.

关键词： Sponge red phosphorus Porous graphene Ni2P Electrode Asymmetric solid-state supercapacitor

Exact solutions for the flow of second grade fluid in annulus between torsionally oscillating cylinders

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Acta Mechanica Sinica 2011年第2期27卷 222-227页

作者： Amir Mahmood Saima parveen Najeeb Alam khan Department of Mathematics COMSATS Institute of Information Technology Lahore Pakistan Abdus Salam School of Mathematical Sciences Lahore Pakistan Department of Mathematics University of Karachi Karachi-75270 Pakistan

The velocity field and the associated shear stress corresponding to the torsional oscillatory flow of a second grade fluid, between two infinite coaxial circular cylinders, are determined by means of the Laplace and Hankel transforms. At time t = 0, the fluid and both the cylinders are at rest and at t = 0 ＋ , cylinders suddenly begin to oscillate around their common axis in a simple harmonic way having angular frequencies ω 1 and ω 2 . The obtained solutions satisfy the governing differential equation and all imposed initial and boundary conditions. The solutions for the motion between the cylinders, when one of them is at rest, can be obtained from our general solutions. Furthermore, the corresponding solutions for Newtonian fluid are also obtained as limiting cases of our general solutions.

关键词： Second grade fluid · Velocity field · Shear stress · Longitudinal oscillatory flow · Laplace and Hankel transforms

Adenyl cyclase activator forskolin protects against Huntington's disease-like neurodegenerative disorders

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Neural Regeneration Research 2017年第2期12卷 290-300页

作者： Sidharth Mehan Shaba parveen Sanjeev kalra Department of Pharamcology Rajendra Institute of Technology & Sciences Sirsa Haryana India

Long term suppression of succinate dehydrogenase by selective inhibitor 3-nitropropionic acid has been used in rodents to model Huntington＇s disease where mitochondrial dysfunction and oxidative damages are primary pathological hallmarks for neuronal damage. Improvements in learning and memory abilities, recovery of energy levels, and reduction of excitotoxicity damage can be achieved through activation of Adenyl cyclase enzyme by a specific phytochemical forskolin. In this study, intraperitoneal administration of 10 mg/kg 3-nitropropionic acid for 15 days in rats notably reduced body weight, worsened motor cocordination（grip strength, beam crossing task, locomotor activity）, resulted in learning and memory deficits, greatly increased acetylcholinesterase, lactate dehydrogenase, nitrite, and malondialdehyde levels, obviously decreased adenosine triphosphate, succinate dehydrogenase, superoxide dismutase, catalase, and reduced glutathione levels in the striatum, cortex and hippocampus. Intragastric administration of forskolin at 10, 20, 30 mg/kg dose-dependently reversed these behavioral, biochemical and pathological changes caused by 3-nitropropionic acid. These results suggest that forskolin exhibits neuroprotective effects on 3-nitropropionic acid-induced Huntington＇s disease-like neurodegeneration.

关键词： nerve regeneration Huntington's disease mitochondria adenyl cyclase forskolin oxidative stress basal ganglia neural regeneration

Deep Learning Framework for Classification of Emoji Based Sentiments

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Computers, Materials & Continua 2022年第8期72卷 3145-3158页

作者： Nighat parveen Shaikh Mumtaz Hussain Mahar Shah Abdul Latif University Khairpur77150Pakistan

Recent patterns of human sentiments are highly influenced by emoji based sentiments(EBS).Social media users are widely using emoji based sentiments(EBS)in between text messages,tweets and *** tiny pictures of emoji contains sufficient information to be considered for construction of classification model;but due to the wide range of dissimilar,heterogynous and complex patterns of emoji with similarmeanings(SM)have become one of the significant research areas of machine *** paper proposes an approach to provide meticulous assistance to social media application(SMA)users to classify the EBS *** methodology consists upon three layerswhere first layer deals with data cleaning and feature selection techniques to detect dissimilar emoji patterns(DEP)with similar meanings(SM).In first sub step we input set of emoji,in second sub step every emoji has to qualify user defined threshold,in third sub step algorithm detects every emoji by considering as objects and in fourth step emoji images are cropped,after data cleaning these tiny images are saved as emoji *** second step we build classification model by using convolutional neural networks(CNN)to explore hidden knowledge of emoji *** third step we present results visualization by using confusion matrix and other *** paper contributes(1)data cleaning method to detect EBS;(2)highest classification accuracy for emoji classification measured as 97.63%.

关键词： Deep learning machine vision convolutional neural networks social media emoji based sentiments