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Cryogenic wedges on the NE Qinghai-tibet and Ordos Plateaus:their characteristics,origin and OSL dating

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Research in Cold and Arid Regions 2021年第6期13卷 463-473页

作者： stua.t a.harris Department of Geography University of CalgaryCalgaryAlbertaT2N 1N4Canada

Cryogenic wedges developed due to very cold,rather arid conditions during the maximum of the last cold event when the drying up of the neighboring China Sea resulted in the failure of the East Asian *** the climate ameliorated and the Monsoon rains reappeared,ice-wedges *** warming permitted thawing of the ice infillings accompanied by replacement of the ice by sediments partly from the host ground as well as from the surface by wind or sheet *** cases of extreme surface water flow on slopes after 10 ka B.P.,small baydjarakhs typically c.50 cm high developed,only to have the resulting hollows infilled by sediments carried by wind and/or sheet *** shallow structures form a network on top of many of the cryogenic *** complex history makes dating the ages of the wedges difficult using OSL ***,past field work ignored the problem of the angle of the cut face to the direction of the wedge infilling when sampling the contents of the narrow wedges,resulting in potential contamination of the samples with the host *** of the larger deposits should be alright,but the likelihood of contamination makes the interpretation of the resulting OSL dates from the narrow wedges *** wedges consisting of primary mineral infillings should still have similar OSL dates with depth for a given wedge,but the distinction between ice-wedge infillings and soil wedges is difficult since both can exhibit older dates of the infillings with *** available data suggests that ice-wedges were significantly more common than sediment-filled primary wedges.A protocol to avoid having to obtain large numbers of OSL dates by more careful field sampling and the use of grain size determinations is provided in the Appendix.

关键词： cryogenic wedges OSL dating NE Qinghai-tibet Plateau differentiation of primary and secondary wedges baydjarakhs in arid climates

Exploring the associations between skeletal muscle echogenicity and physical function in aging adults:A systematic review with meta-analyses

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Journal of Sport and Health Science 2024年第6期13卷 820-840页

作者： Dustin J.Oranchuk Stephan G.Bodkin Katie L.Boncella Michael O.harris-Love Muscle Morphology Mechanicsand Performance LaboratoryDepartment of Physical Medicine and RehabilitationUniversity of Colorado Anschutz Medical CampusAuroraCO 80045USA Department of Physical therapy

Background:Assessment and quantification of skeletal muscle within the aging population is vital for diagnosis,treatment,and injury/disease *** clinical availability of assessing muscle quality through diagnostic ultrasound presents an opportunity to be utilized as a screening tool for function-limiting ***,relationships between muscle echogenicity and clinical functional assessments require authoritative ***,we aimed to(a) synthesize the literature to assess the relationships between skeletal muscle echogenicity and physical function in older adults(≥60 years),(b) perform pooled analyses of relationships between skeletal muscle echogenicity and physical function,and(c) perform sub-analyses to determine between-muscle ***:CINAHL,Embase,MEDLINE,PubMed,and Web of Science databases were systematically searched to identify articles relating skeletal muscle echogenicity to physical function in older ***-of-bias assessments were conducted along with funnel plot ***-analyses with and without sub-analyses for individual muscles were performed utilizing Fisher's Z transformation for the most common measures of physical ***'s Z was back-transformed to Pearson's r for ***:Fifty-one articles(n=5095,female=~2759,male=~2301,72.5± 5.8 years,mean±SD(1 study did not provide sex descriptors))were extracted for review,with previously unpublished data obtained from the authors of 13 *** rectus femoris(n=34) and isometric knee extension strength(n=22) were the most accessed muscle and physical qualities,*** relationship between quadriceps echogenicity and knee extensor strength was moderate(n=2924,r=-0.36(95% confidence interval:-0.38 to-0.32),p th all other meta-analyses(grip strength,walking speed,sit-to-stand,timed up-and-go) resulting in slightly weaker correlations(r:-0.34 to-0.23,all p termined minimal differences in predicti

关键词： Correlations Echo intensity Elderly Intramuscular fat Strength

Identification,characteristics and classification of cryogenic block streams

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Research in Cold and Arid Regions 2016年第3期8卷 177-186页

作者： stua.t a.harris Department of Geography University of CalgaryCanada T2N 1N4

Cryogenic block streams consist of a stream of rocks superficially resembling a stream deposit but lacking a matrix, usually occurring on a valley or gully floor or on slopes that are less steep than the maximum angle of repose of coarse sediments. they are usually formed on perennially frozen ground, but can also occur as relict landforms. there are three main active kinds forming today, viz., Siberian and tibetan dynamic rock streams and lag block streams. During their formation, the blocks in the active Siberian and tibetan dynamic block streams move downslope at up to 1 rn/a. they are forming today on the tibetan Plateau and in the more arid parts of south-central Siberia, although the processes involved in the movement are different. In the case of the tibetan type, individual blocks slide downslope over the substrate in winter on an icy coating in areas of minimal winter precipitation. the Siberian type develops in areas of 15-80 cm of winter snow cover and an MAAt （mean annual air temperature） of-4 ~C to -17 ~C. the movement is due to creep of snow and ice and collapse of the blocks downslope during thawing. Lag block streams are formed by meltwater flowing over the surface of sediment consisting primarily of larger blocks with a limited amount of interstitial sediment. the erosion of the matrix is primarily in the spring in areas of higher winter precipitation on 10^-30~ slopes. the blocks remain stationary, but the interstitial sediment is washed out by strong seasonal flows of meltwater or rain to form an alluvial fan. the boulders undergo weathering and become more rounded in the process. Lag block streams can also develop without the presence of permafrost in areas with cold climates or glaciers. Block streams also occur as relict deposits in older deposits under various climatic regimes that are unsuitable for their formation today. An example of relict lag block streams with subangular to subrounded blocks occurs in gullies on the forested mountainside

关键词： active dynamic block streams felsemeer relict block steams tibetan type block streams Siberian typeblock streams lag block streams

Probable effects of heat advection on the adjacent environment during oil production at Prudhoe Bay, Alaska

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Research in Cold and Arid Regions 2016年第6期8卷 451-460页

作者： stua.t a.harris Department of Geography University of Calgary Calgary Alberta T2N 1N4 Canada

the latest available data for mean annual air temperature at sites away from the Arctic coast in both Alaska and the Yukon territory show no significant warming in the last 30-50 years. However, around the Arctic coast of northwest North America centered on Prudhoe Bay, the weather stations show significant warming of both the air and the ocean water, resulting in substantial losses in sea ice west of Prudhoe Bay. these changes appeared shortly after the commencement of shipment of oil through the trans-Alaska Pipeline in 1977, but have now reached a quasi-stable thermal state. Since more than 17 trillion barrels of oil have passed through the pipeline after being cooled by the adjacent air, which in turn, can then result in the melting of the adjacent sea ice, there appears to be a very strong relationship between these events, and a marked lack of correlation with the changes of the content of greenhouse gases in the atmosphere. this contrasts with the IPCC interpretation of the available climatic data, which assumes that the maximum climatic warming at Prudhoe Bay is typical of the entire region and is the result of increasing greenhouse gases. Engineers need to consider heat advection by oil or gas from underground when designing pipeline facilities, and to take account of the potential environmental con-sequences that they may cause.

关键词： Prudhoe Bay mean annual air temperature heat advection due to oil Arctic ice cover trans-Alaska Pipeline greenhouse gases Arctic marine ecosystems

From source to emplacement:the origin of leucogranites from the Sikkim-Darjeeling Himalayas,India

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Geoscience Frontiers 2024年第1期15卷 384-401页

作者： tanya Srivastava Nigel harris Catherine Mottram Kumar Batuk Joshi Nishchal Wanjari Department of Geology Sikkim UniversityGangtokIndia School of Environment Earth&Ecosystem SciencesOpen UniversityMiltonKeynesUK School of the Environment Geography and GeosciencesUniversity of PortsmouthUK National Centre for Earth Science Studies ThiruvananthapuramKeralaIndia

Himalayan leucogranites are important for understanding the tectonic evolution of collision zones in general and the causes of crustal melting in the Himalayan orogen in *** paper aims to understand the melt source and emplacement age of the leucogranites from Sikkim in order to decipher the deep geodynamic processes of the eastern *** U-Pb analysis of the Higher Himalayan Sequence(HHS)metamorphic core reveals a prolonged period of crustal melting between>33 Ma and ca.14 *** and trace element abundances are presented for 27 leucogranites from North Sikkim that are classified into two-mica and tourmaline leucogranite *** are peraluminous in composition,characterized by high SiO2(70.91-74.9 wt.%),Al2O3(13.69-15.82 wt.%),and low MgO(0.13-0.74 wt.%).Elemental abundances suggest that Sikkim Himalayan leucogranites are derived from crustal *** two-mica leucogranites are derived from a metagreywacke source,whereas the tourmaline leucogranites are sourced from metapelitic sources,with inherited zircons indicating an HHS origin for both types.U-Pb zircon geochronology of the two mica leucogranites indicates ages of ca.19-15 Ma,consistent with crustal melting recorded in HHS gneisses from *** from both the two-mica and tourmaline leucogranites yield a crystallization age of ca.15-14 Ma,coeval with movement on the Main Central thrust and South tibetan Detachment System which further provides constraints on the timing and mechanism of petrogenesis of leucogranites in the Sikkim Himalayas.

关键词： Leucogranites Gneiss U-Pb geochronology Zircon Monazite Sikkim-Darjeeling Himalayas

Climate change and permafrost stability in the eastern Canada Cordillera:the results of 33 years of measurements

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Research in Cold and Arid Regions 2009年第5期1卷 381-403页

作者： stua.t a.harris Department of Geography University of Calgary

Over the last 33 years,a network of climate stations has been set up at high altitude mountain permafrost sites from Plateau Mountain near Claresholm,Alberta,north to Sheldon Lake on the North Canol Road in the *** together with the data from the US National Weather Service and the Canadian Atmospheric Environment Service,the results indicate a cooling of mean annual air temperature south of Calgary,no significant change in Calgary,a slight warming at Jasper,and a major warming at Summit Lake,west of Fort *** contrast,the south eastern and central Yukon show only a minor warming trend that lies well within the limits of a sixty-year record measured by the Canadian Atmospheric Environment *** the Mackenzie valley and on the North Slope of Alaska,the mean annual air temperature is *** is aggrading on Plateau Mountain,degrading at Summit Lake,and appears to be stable in southern Yukon and southern *** is in contrast to the warming occurring on the Arctic coastal plain and along the Mackenzie *** therefore appears that changes in climate vary considera-bly from place to place,and even where warming may occur,it may not continue *** has been a northward shift of the arctic front due to a weakening of air pressure in the Yukon and Alaska relative to the continental tropical(ct) and maritime polar(mt) air masses to the *** actual changes that may be occurring appear to undergo amplification along the Mackenzie valley and Arctic coastal plain and reduction by buffering in the interior Yukon and Alaskan mountains,a result of mi-cro-environmental ***,careful monitoring of the climate is required and needs to be expanded in the National Parks in the mountains in order to provide data on the changes that may be taking *** measurements can provide a sound basis for interpreting ecological and other climate-related *** existing climate models are not working satisfactorily because w

关键词： permafrost stability long-term measurement climate change the Eastern Canada Cordillera

Impacts of degrading permafrost on streamflow in the source area of Yellow River on the Qinghai-tibet Plateau,China

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Advances in Climate Change Research 2019年第4期10卷 225-239页

作者： MA Qiang JIN Hui-Jun Victor F.BENSE LUO Dong-Liang Sergey S.MARCHENKO stua.t a.harris LAN Yong-Chao State Key Laboratory of Frozen Soils Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China School of Civil Engineering Harbin Institute of TechnologyHarbin150090China Hydrology and Quantitative Water Management Group Department of Environmental SciencesWageningen UniversityWageningen6708PBthe Netherlands Geophysical Institute(GIPL) University of Alaska FairbanksFairbanks99775USA Department of Geography University of CalgaryCalgaryT3A 1E4Canada

Many observations in and model simulations for northern basins have confirmed an increased streamflow from degrading permafrost,while the streamflow has declined in the source area of the Yellow River(SAYR,above the tanag hydrological station)on the northeastern Qinghai-tibet Plateau,West *** and to what extent does the degrading permafrost change the flow in the SAYR?According to seasonal regimes of hydrological processes,the SAYR is divided intofour sub-basins with varied permafrost extents to detect impacts of permafrost degradation on the Yellow River *** show that permafrost degradation may have released appreciable meltwater for recharging *** potential release rate of ground-ice melt-water in the Sub-basin 1(the headwater area of the Yellow River(HAYR),above the Huangheyan hydrological station)is the highest(5.6 mm per year),contributing to 14.4%of the annual Yellow River streamflow at ***/intra-and annual shifts of streamflow,a possible signal for the marked alteration of hydrological processes by permafrost degradation,is observed in the HAYR,but the shifts are minor in other sub-basins in the *** hydraulic connectivity is expected to occur during and after certain degrees of permafrost *** impacts of permafrost degradation on the annual Yellow River streamflow in the SAYR at tanag,i.e.,from the meltwater of ground-ice,is estimated at 4.9%that of the annual Yellow River discharge at tanag,yet with a high uncertainty,due to neglecting of the improved hydraulic connections from permafrost degradation and the flow generation conditions for the ground-ice *** evapotranspiration,substantial weakening of the Southwest China Autumn Rain,and anthropogenic disturbances may largely account for the declined streamflow in the SAYR.

关键词： Streamflow Warming climate Permafrost degradation Streamflow patterns Source area of Yellow River(SAYR)

Particle elasticity influences polymeric artificial antigen presenting cell effectiveness in vivo via CD8+t cell activation,macrophage uptake,and the protein corona

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Nano Research 2024年第10期17卷 9052-9064页

作者： Savannah E.Est-Witte Sydney R.Shannon Dennis H.Gong Kaitlyn G.Calabresi Jawaun J.harris Kaitlyn Storm Edwin J.Yoo Ariel Isser Vivek P.Jani Natalie K.Livingston Mary O.Omotoso Kelly Rhodes Elana Ben-Akiva Randall A.Meyer Zoe t.Hsieh Simone Sidoli Stephany Y.tzeng Jonathan P.Schneck Jordan J.Green translational tissue Engineering Center Institute for NanobiotechnologyDepartment of Biomedical EngineeringJohns Hopkins School of Medicine400 N BroadwayBaltimoreMD 21231USA Institute for Cell Engineering Department of PathologyJohns Hopkins School of Medicine733 N BroadwayBaltimoreMD 21205USA Department of Biochemistry Albert Einstein College of MedicineThe BronxNew York CityNY 10461USA

Adoptive cell therapy(ACt)is an immunotherapy strategy for cancer that has seen widespread clinical *** ACt,patient-derived lymphocytes are stimulated with the antigen of interest ex vivo,proliferated,then returned to the patient to initiate an antigen-specific antitumor *** effective,this process is resource-intensive and logistically impossible for many *** artificial antigen presenting cells(aAPCs)offer a potential“off-the-shelf”alternative to ex vivo *** particulate aAPCs perform well in vitro,they have had limited success in vivo due to poor bioavailability after *** to bioavailability include rapid clearance,unfavorable biodistribution,and inadequate interactions with CD8+t cells at sites of *** properties such as elasticity have been shown to vastly impact the bioavailability and particle-cell interactions,but this has yet to be investigated in the context of aAPCs for in vivo t-cell *** literature likewise indicates that biomaterial properties,especially elasticity,can modulate t-cell activation in *** the goal of creating a more biomimetic,next-generation particulate aAPC,we developed a poly(ethylene)glycol hydrogel particle platform with tunable elasticity to investigate the impact of elasticity on antigen-specific t cell activation for in vivo adoptive *** this knowledge,we were able to gain more precise control over in vivo t cell activation and investigate possible mechanisms including the effects of aAPC elasticity on t cell binding,macrophage uptake,and the protein corona.

关键词： adoptive cell therapy artificial antigen presenting cells particle drug delivery elasticity protein corona poly(ethylene glycol)

tessellons, topography, and glaciations on the Qinghai-tibet Plateau

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Research in Cold and Arid Regions 2018年第3期10卷 187-206页

作者： stua.t a.harris Hui Jun Jin Rui Xia He Si Zhong Yang Department of Geography University of Calgary State Key Laboratory of Frozen Soils Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences

the Qinghai-tibet Plateau has developed into a vast fortress-like structure that has recently presented a barrier limiting the egress of moisture-bearing air masses. Lower sea levels also affected the climate. this paper examines their effects on the current evidence for the timing of past glaciations, and the development and evolution of permafrost. there are two theories regarding glaciation on the Qinghai-tibet Plateau （QtP）. Kuhle suggested that there was a major, unified ice-cap during the Last Glacial Maximum （LGM）, whereas major Chinese glaciologists and others have not found or verified reliable evidence for this per se. there have been limited glaciations during the last 1.1 Ma B.P. but with increasing dominance of permafrost including both primary and secondary tessellons infilled with rock, sand or loess. the East Asia Monsoon was absent in this area during the main LGM, starting at 〉30 ka B.P. on the plateau, with sufficient precipitation reappearing about 19 ka B.P. to produce ice-wedges. A weak Megathermal event took place between 8.5 and 6.0 ka B.P., followed by Neoglacial events exhibiting peak cold at 5.3-4.7 ka, 3.1-1.5 ka, and the Little Ice Age （LIA） after 0.7 ka. Subsequently, mean annual air temperature has increased by 4 ℃.

关键词： glaciation of the Qinghai-tibet Plateau (QtP) tessellons East Asia Monsoon Last Glacial Maximum (LGM) Neoglaciation Asian climate change