WorldWideScience

Sample records for human-induced arctic moistening

  1. Human-induced Arctic moistening.

    Science.gov (United States)

    Min, Seung-Ki; Zhang, Xuebin; Zwiers, Francis

    2008-04-25

    The Arctic and northern subpolar regions are critical for climate change. Ice-albedo feedback amplifies warming in the Arctic, and fluctuations of regional fresh water inflow to the Arctic Ocean modulate the deep ocean circulation and thus exert a strong global influence. By comparing observations to simulations from 22 coupled climate models, we find influence from anthropogenic greenhouse gases and sulfate aerosols in the space-time pattern of precipitation change over high-latitude land areas north of 55 degrees N during the second half of the 20th century. The human-induced Arctic moistening is consistent with observed increases in Arctic river discharge and freshening of Arctic water masses. This result provides new evidence that human activity has contributed to Arctic hydrological change.

  2. Process-oriented moistening diagnostics applied to the MJO

    Science.gov (United States)

    Maloney, E. D.; Wolding, B.

    2016-12-01

    A large recent body of literature suggests that the Madden-Julian oscillation (MJO) is a tropical disturbance regulated by weak temperature gradients (WTG), and that understanding free tropospheric moistening processes is crucial for understanding its destabilization and propagation. We present new process-oriented moistening diagnostics of the MJO that exploit WTG theory. In these diagnostics, vertical velocity can be diagnosed as that required to balance diabatic heating anomalies, and then this diagnosed vertical velocity acts as an agent of vertical moisture advection. The net effect of convection on the tropospheric moisture budget includes this vertical moisture advection plus moisture removal by condensational processes. Application of these diagnostics to ERA-I and the superparameterized CESM (Sp-CESM) fields indicates that radiative feedbacks are an important destabilization process for the MJO, and that horizontal advection is a major propagation mechanism. Basic state model errors in Sp-CESM produce a surface flux feedback of the wrong sign compared to ERA-i. These diagnostics are then applied to a model with a poor MJO simulation, demonstrating their ability to diagnose deficiencies in the major intraseasonal moistening processes and suggest pathways for parameterization improvement. The presentation will end with a brief discussion on NOAA MAPP Model Diagnostics Task Force progress toward developing a software framework to speed integration of new process-oriented diagnostics into climate and weather forecasting model evaluation packages.

  3. Upper-tropospheric moistening in response to anthropogenic warming.

    Science.gov (United States)

    Chung, Eui-Seok; Soden, Brian; Sohn, B J; Shi, Lei

    2014-08-12

    Water vapor in the upper troposphere strongly regulates the strength of water-vapor feedback, which is the primary process for amplifying the response of the climate system to external radiative forcings. Monitoring changes in upper-tropospheric water vapor and scrutinizing the causes of such changes are therefore of great importance for establishing the credibility of model projections of past and future climates. Here, we use coupled ocean-atmosphere model simulations under different climate-forcing scenarios to investigate satellite-observed changes in global-mean upper-tropospheric water vapor. Our analysis demonstrates that the upper-tropospheric moistening observed over the period 1979-2005 cannot be explained by natural causes and results principally from an anthropogenic warming of the climate. By attributing the observed increase directly to human activities, this study verifies the presence of the largest known feedback mechanism for amplifying anthropogenic climate change.

  4. Spatial stabilization and intensification of moistening and drying rate patterns under future climate change

    Science.gov (United States)

    Chavaillaz, Yann; Joussaume, Sylvie; Bony, Sandrine; Braconnot, Pascale

    2016-08-01

    Precipitation projections are usually presented as the change in precipitation between a fixed current baseline and a particular time in the future. However, upcoming generations will be affected in a way probably more related to the moving trend in precipitation patterns, i.e. to the rate and the persistence of regional precipitation changes from one generation to the next, than to changes relative to a fixed current baseline. In this perspective, we propose an alternative characterization of the future precipitation changes predicted by general circulation models, focusing on the precipitation difference between two subsequent 20-year periods. We show that in a business-as-usual emission pathway, the moistening and drying rates increase by 30-40 %, both over land and ocean. As we move further over the twenty-first century, more regions exhibit a significant rate of precipitation change, while the patterns become geographically stationary and the trends persistent. The stabilization of the geographical rate patterns that occurs despite the acceleration of global warming can be physically explained: it results from the increasing contribution of thermodynamic processes compared to dynamic processes in the control of precipitation change. We show that such an evolution is already noticeable over the last decades, and that it could be reversed if strong mitigation policies were quickly implemented. The combination of intensification and increasing persistence of precipitation rate patterns may affect the way human societies and natural ecosystems adapt to climate change, especially in the Mediterranean basin, in Central America, in South Asia and in the Arctic.

  5. Motion of a three-phase contact line on a moistened surface

    Science.gov (United States)

    Shikhmurzaev, Yu. D.

    1992-12-01

    The motion of the line of contact in gas-liquid-solid systems is investigated theoretically for low values of the capillary and Reynolds numbers. The analysis allows for the possible presence on the solid substrate of a microscopic residual film formed by adsorbed liquid molecules. A comparison is made of the spreading characteristics of the liquid for dry and moistened solid substrates. Based on the experimental data and the model used, the motion of the liquid during wetting is characterized as a rolling motion. The increase in the dynamic contact angle during the wetting of a moistened surface is found to be slower than in the case of a dry substrate. The maximum dynamic contact angle in the case of a moistened substrate is significantly less than 180 deg.

  6. Physical quality of grains subjected to moistening and drying processes for marketing

    Directory of Open Access Journals (Sweden)

    Paulo C. Coradi

    Full Text Available ABSTRACT The aim was to evaluate the physical quality of conventional and transgenic corn grains, through drying and wetting processes for marketing. The experimental design was completely randomized in a factorial scheme (7 x 3 x 2, corresponding to seven drying times (0, 20, 40, 60, 80, 100 and 120 min, three temperatures of the drying air (80, 100 and 120 °C and two hybrids of corn (conventional AG 1051 and transgenic Herculex@ 30S31H. Grain drying was held in convection oven with forced air ventilation while the wetting was done in a B.O.D chamber. The water movement in the grain, the volume and the electrical conductivity were evaluated periodically. The results showed that the transgenic corn grain reduced the negative effects of drying and moistening on the physical quality. The increase in drying air temperature accelerated the physical deterioration of conventional and transgenic corn grains. The increase in water content by the moistening process caused losses in grain physical quality, similar to the drying process, for both the conventional and transgenic corn grains.

  7. The cooling and moistening effect on the formation of sea fog in the Huanghai Sea

    Institute of Scientific and Technical Information of China (English)

    HUANG Jian; ZHOU Faxiu

    2006-01-01

    With the sea surface observations from ICOADS for the years 1960~2002, the conditions of cooling, evaporation and water vapor transportation are analyzed and compared for the formation of seasonal sea fog in April-July in the Huanghai Sea. It is found that sea surface cooling is always existent during the fog seasons while sea surface evaporation only appears in April-June in the Huanghai Sea. Local evaporation alone is not sufficient to form fogs though it may lead to light ones. Water vapor transported from the low-latitudes accomplished by specific synoptic systems is the most important condition for sea fog formation. In general, the moistening effect is more important than the cooling one.

  8. Evidence for Tropopause Layer Moistening by Convection During CRYSTAL-FACE

    Science.gov (United States)

    Ackerman, A.; Fridlind, A.; Jensen, E.; Miloshevich, L.; Heymsfield, G.; McGill, M.

    2003-01-01

    Measurements and analysis of the impact of deep convection on tropopause layer moisture are easily confounded by difficulties making precise observations with sufficient spatial coverage before and after convective events and difficulties distinguishing between changes due to local convection versus large-scale advection. The interactions between cloud microphysics and dynamics in the convective transport of moisture into the tropopause layer also result in a sufficiently complex and poorly characterized system to allow for considerable freedom in theoretical models of stratosphere-troposphere exchange. In this work we perform detailed large-eddy simulations with an explicit cloud microphysics model to study the impact of deep convection on tropopause layer moisture profiles observed over southern Florida during CRYSTALFACE. For four days during the campaign (July 11, 16, 28, and 29) we initialize a 100-km square domain with temperature and moisture profiles measured prior to convection at the PARSL ground site, and initiate convection with a warm bubble that produces an anvil at peak elevations in agreement with lidar and radar observations on that day. Comparing the moisture field after the anvils decay with the initial state, we find that convection predominantly moistens the tropopause layer (as defined by minimum temperature and minimum potential temperature lapse rate), although some drying is also predicted in localized layers. We will also present results of sensitivity tests designed to separate the roles of cloud microphysics and dynamics.

  9. Biogeochemistry of heavy metals in contaminated excessively moistened soils (Analytical review)

    Science.gov (United States)

    Vodyanitskii, Yu. N.; Plekhanova, I. O.

    2014-03-01

    The biogeochemical behavior of heavy metals in contaminated excessively moistened soils depends on the development of reducing conditions (either moderate or strong). Upon the moderate biogenic reduction, Cr as the metal with variable valence forms low-soluble compounds, which decreases its availability to plants and prevents its penetration into surface- and groundwater. Creation of artificial barriers for Cr fixation on contaminated sites is based on the stimulation of natural metal-reducing bacteria. Arsenic, being a metalloid with a variable valence, is mobilized upon the moderate biogenic reduction. The mobility of siderophilic heavy metals with a constant valence grows under the moderate reducing conditions at the expense of dissolution of iron (hydr)oxides as carriers of these metals. Zinc, which can enter the newly formed goethite lattice, is an exception. Strong reduction processes in organic excessively moist and flooded soils (usually enriched in S) lead to the formation of low-soluble sulfides of heavy elements with both variable (As) and constant (Cu, Ni, Zn, and Pb) valence. On changing aquatic regime in overmoistened soils and their drying, sulfides of heavy metals are oxidized, and previously fixed metals are mobilized.

  10. The Moistening and Drying Effect of Tropical Cyclones in Mexico Climate

    Science.gov (United States)

    Domínguez Sarmiento, C.; Magaña Rueda, V.

    2013-05-01

    Tropical Cyclones (TCs) are supplying mechanisms of water to the country and allow recharging aquifers, rivers, lakes and stratus of groundwater. TCs play a more important role in the hydrological cycle of northern Mexico and they are such an essential elements during summer rainfall seasons in Mexico that if they did not exist, summer rainfall would decrease its amount by half in numerous Mexican regions. For instance, there could be a high TC activity both Atlantic and Pacific Ocean, a rainfall season could not be enough to become important if TCs do not pass over Mexico. We examine the two opposite effects of Tropical Cyclones (TCs) on Mexico, during the period 1979-2009, by means of a probabilistic clustering technique. One TC effect is their contribution to summer rainfall, which is defined as "the moistening effect". The other effect is to dry regions due to subsidence induced by their circulation, which is defined as "the drying effect". The TCs tracks for the North Atlantic and Eastern North Pacific Oceans are obtained from the best-track database of National Hurricane Centre (HURDAT and EPA). Four principal types of tracks (clusters) in both basins are defined and each cluster has a different impact on Mexico. Consequently, this shows how important defining clusters are to analyze TC effects. We conclude that, climatologically, TCs may contribute up to 30% of summer rainfall depending on the cluster. In addition, the subsidence effect is not large, compared to the generated amount of precipitation in a region, but acts to produce negative precipitation anomalies over Mexican regions that depend on their distance of the system to Mexico.

  11. Water used to moisten vegetables is a source of Escherichia coli and protozoan parasite contamination at markets in Hanoi, Vietnam.

    Science.gov (United States)

    Tram, Nguyen Thuy; Dalsgaard, Anders

    2014-12-01

    The study was done to assess the level of fecal (Escherichia coli) and protozoan parasite (Cryptosporidium spp. and Giardia spp.) contamination in water used by traders to moisten vegetables at markets in Hanoi, Vietnam. A total of 200 splashing water samples from markets located within eight districts were analyzed for E. coli and Cryptosporidium spp. and Giardia spp. (oo)cysts. Giardia cysts were found in 17 splashing water samples and Cryptosporidium oocysts in nine samples, with median values of 20 cysts ml(-1) and 10 oocysts ml(-1), respectively. E. coli was found with a median concentration of 636 cfu ml(-1) and its occurrence was negatively correlated with the numbers of protozoan parasites. The splashing water was kept in buckets that were rarely cleaned and often used for handwashing. The finding of these pathogens in splashing water is likely to represent real food safety hazards.

  12. Effect of Reinforcing Qi and Moistening Intestine Oral Liquid on Anorectal Manometry of Asthenia Type Constipation Patients

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To study the change of anorectal manometry in asthenia type constipation patients and effect of reinforcing Qi and moistening intestine oral liquid (RQMI) on it. Methods: The total of 135 cases were divided into healthy group, RQMI treated group, Maren pill (MRP) treated group and prepulsid (PPS) treated group, their anal maximal voluntary squeez pressure, rectoanal contraction reflex, rectoanal inhibitory reflex, defecation reflex, rectal volume sensory threshold and rectal maximal tolerable volume were observed. Results: The rectal sensory function of patients weakened obviously and anal sphincter reactivity reduced as compared with those of healthy person (P<0.01), and both were improved by RQMI treatment (P<0.05). Conclusion: RQMI is superior to MRP and prepulside in improving anorectal dynamic abnormality in constipation patient of asthenia type.

  13. Arctic methane

    NARCIS (Netherlands)

    Dyupina, E.; Amstel, van A.R.

    2013-01-01

    What are the risks of a runaway greenhouse effect from methane release from hydrates in the Arctic? In January 2013, a dramatic increase of methane concentration up to 2000 ppb has been measured over the Arctic north of Norway in the Barents Sea. The global average being 1750 ppb. It has been

  14. Arctic Newcomers

    DEFF Research Database (Denmark)

    Tonami, Aki

    2013-01-01

    Interest in the Arctic region and its economic potential in Japan, South Korea and Singapore was slow to develop but is now rapidly growing. All three countries have in recent years accelerated their engagement with Arctic states, laying the institutional frameworks needed to better understand an...

  15. Arctic methane

    NARCIS (Netherlands)

    Dyupina, E.; Amstel, van A.R.

    2013-01-01

    What are the risks of a runaway greenhouse effect from methane release from hydrates in the Arctic? In January 2013, a dramatic increase of methane concentration up to 2000 ppb has been measured over the Arctic north of Norway in the Barents Sea. The global average being 1750 ppb. It has been sugges

  16. Arctic Watch

    Science.gov (United States)

    Orcutt, John; Baggeroer, Arthur; Mikhalevsky, Peter; Munk, Walter; Sagen, Hanne; Vernon, Frank; Worcester, Peter

    2015-04-01

    The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This will be driven by increased demand for energy and the marine resources of an Arctic Ocean more accessible to ships. Oil and gas exploration, fisheries, mineral extraction, marine transportation, research and development, tourism and search and rescue will increase the pressure on the vulnerable Arctic environment. Synoptic in-situ year-round observational technologies are needed to monitor and forecast changes in the Arctic atmosphere-ice-ocean system at daily, seasonal, annual and decadal scales to inform and enable sustainable development and enforcement of international Arctic agreements and treaties, while protecting this critical environment. This paper will discuss multipurpose acoustic networks, including subsea cable components, in the Arctic. These networks provide communication, power, underwater and under-ice navigation, passive monitoring of ambient sound (ice, seismic, biologic and anthropogenic), and acoustic remote sensing (tomography and thermometry), supporting and complementing data collection from platforms, moorings and autonomous vehicles. This paper supports the development and implementation of regional to basin-wide acoustic networks as an integral component of a multidisciplinary, in situ Arctic Ocean Observatory.

  17. Arctic Shipping

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Grønsedt, Peter; Lindstrøm Graversen, Christian

    , the latter aiming at developing key concepts and building up a basic industry knowledge base for further development of CBS Maritime research and teaching. This report attempts to map the opportunities and challenges for the maritime industry in an increasingly accessible Arctic Ocean...

  18. Global review of human-induced earthquakes.

    OpenAIRE

    Foulger, Gillian R.; Wilson, Miles; Gluyas, Jon; Julian, Bruce R.; Davies, Richard

    2017-01-01

    The Human-induced Earthquake Database, HiQuake, is a comprehensive record of earthquake sequences postulated to be induced by anthropogenic activity. It contains over 700 cases spanning the period 1868–2016. Activities that have been proposed to induce earthquakes include the impoundment of water reservoirs, erecting tall buildings, coastal engineering, quarrying, extraction of groundwater, coal, minerals, gas, oil and geothermal fluids, excavation of tunnels, and adding material to the subsu...

  19. Arctic Ocean

    Science.gov (United States)

    Parkinson, Claire L.; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    The Arctic Ocean is the smallest of the Earth's four major oceans, covering 14x10(exp 6) sq km located entirely within the Arctic Circle (66 deg 33 min N). It is a major player in the climate of the north polar region and has a variable sea ice cover that tends to increase its sensitivity to climate change. Its temperature, salinity, and ice cover have all undergone changes in the past several decades, although it is uncertain whether these predominantly reflect long-term trends, oscillations within the system, or natural variability. Major changes include a warming and expansion of the Atlantic layer, at depths of 200-900 m, a warming of the upper ocean in the Beaufort Sea, a considerable thinning (perhaps as high as 40%) of the sea ice cover, a lesser and uneven retreat of the ice cover (averaging approximately 3% per decade), and a mixed pattern of salinity increases and decreases.

  20. Arctic Diatoms

    DEFF Research Database (Denmark)

    Tammilehto, Anna

    are often dominated by diatoms. They are single-celled, eukaryotic algae, which play an essential role in ocean carbon and silica cycles. Many species of the diatom genus Pseudo-nitzschia Peragallo produce a neurotoxin, domoic acid (DA), which can be transferred to higher levels in food webs causing amnesic...... as vectors for DA to higher levels in the arctic marine food web, posing a possible risk also to humans. DA production in P. seriata was, for the first time, found to be induced by chemical cues from C. finmarchicus, C. hyperboreus and copepodite stages C3 and C4, suggesting that DA may be related to defense...... against grazing. This thesis also quantified population genetic composition and changes of the diatom Fragilariopsis cylindrus spring bloom using microsatellite markers. Diatom-dominated spring blooms in the Arctic are the key event of the year, providing the food web with fundamental pulses of organic...

  1. Arctic Social Sciences: Opportunities in Arctic Research.

    Science.gov (United States)

    Arctic Research Consortium of the United States, Fairbanks, AK.

    The U.S. Congress passed the Arctic Research and Policy Act in 1984 and designated the National Science Foundation (NSF) the lead agency in implementing arctic research policy. In 1989, the parameters of arctic social science research were outlined, emphasizing three themes: human-environment interactions, community viability, and rapid social…

  2. Drying and moistening by deep sub-tropical and tropical convection in large-eddy simulations of CRYSTAL-FACE and CEPEX field measurements

    Science.gov (United States)

    Ackerman, A. S.; Fridlind, F. M.; Jensen, E. J.; Stevens, D. E.; Miloshevich, L. M.; Baumgardner, D.; Lawson, P.

    2003-12-01

    Deep convection has been proposed to be a leading mechanism controlling the moisture in the lower stratosphere. We evaluate this hypothesis with large-eddy simulations that resolve the size distributions of aerosols and cloud particles over 100-km square square domain using pre-convective Miami and PARSL soundings, initiating convection with enough of a surface heat source to match the observed anvil altitudes. Differencing the moisture field after the anvils decay with the initial state, we find that convection predominantly moistens the transitional tropopause layer (TTL), although some drying is predicted in localized layers. Beyond the sub-tropical convection of Florida we also use frostpoint hygrometer soundings obtained during the CEPEX mission in the tropical western Pacific, which show repeated evidence of supersaturated layers within the TTL. In such cases we find that deep convection dries out the supersaturated layers while moistening the air above and below. We also analyze the environmental and temporal dependence of the time constants of sedimentation, evaporation, and mixing of water.

  3. SubArctic Oceans and Global Climate

    Science.gov (United States)

    Rhines, P. B.

    2004-12-01

    The passages connecting the Arctic Ocean with the Atlantic and Pacific, and their `mediterranean' basins, are focal points for the global meridional overturning circulation, and all of the climate impacts which this implies. It is also a difficult region to model accurately: the sensitivity of climate models to subpolar ocean dynamics is well-known. In this talk we stress the need to instrument and analyze the subpolar oceans, and some examples of sustained observations developing there. Results from satellite altimetry, recent Seaglider deployments from Greenland, and mooring arrays will be described. In particular we show the first Seaglider sections of hydrography and bio-optical profiles of the Labrador Sea (one of the first extended deployments of this autonomous undersea vehicle); we discuss the decline during the 1990s of the subpolar gyre circulation of the Atlantic from its great strength during the positive NAO period of the early 1990s, and its relevance to the salinity decline observed over a much longer period; we review observations of the flows at the Iceland-Scotland Ridge and Davis Strait, argued in terms of volume transport plots on the potential temperature/salinity plane; we display maps of the `convection resistance' (related to dynamic height) and its sensitivity to surface low-salinity water masses and their partition between shallow continental shelves and deep ocean. This is a particularly exciting time for climate studies, with fundamental properties of the atmosphere-ocean circulation under debate, even before one considers natural and human-induced variability. Is the four-decade long decline in subArctic salinity the result of increased hydrologic cycle, increased or altered Arctic outflow to the Atlantic, or slowing of the subpolar circulation? Is the basic intensity of the MOC more dependent on high-latitude buoyancy forcing, or wind- or tide-driven mixing in the upwelling branch, or possibly wind-stress at high latitude? Is the

  4. Barry Lopez's Relational Arctic

    OpenAIRE

    Kjeldaas, Sigfrid

    2014-01-01

    "Arctic dreams: imagination and desire in a Northern landscape"(1986) can be read as American nature writer Barry Lopez’s attempt to evoke a more profound and ecologically sound understanding of the North American Arctic. This article investigates how Arctic Dreams uses insights from Jacob von Uexküll’s Umwelt theory, in combination with what Tim Ingold describes as a particular form of animism associated with circumpolar indigenous hunter cultures, to portray the Arctic natur...

  5. Research with Arctic peoples

    DEFF Research Database (Denmark)

    Smith, H Sally; Bjerregaard, Peter; Chan, Hing Man

    2006-01-01

    Arctic peoples are spread over eight countries and comprise 3.74 million residents, of whom 9% are indigenous. The Arctic countries include Canada, Finland, Greenland (Denmark), Iceland, Norway, Russia, Sweden and the United States. Although Arctic peoples are very diverse, there are a variety of...

  6. Islands of the Arctic

    Science.gov (United States)

    Overpeck, Jonathan

    2004-02-01

    Few environments on Earth are changing more dramatically than the Arctic. Sea ice retreat and thinning is unprecedented in the period of the satellite record. Surface air temperatures are the warmest in centuries. The biology of Arctic lakes is changing like never before in millennia. Everything is pointing to the meltdown predicted by climate model simulations for the next 100 years. At the same time, the Arctic remains one of the most pristine and beautiful places on Earth. For both those who know the Arctic and those who want to know it, this book is worth its modest price. There is much more to the Arctic than its islands, but there's little doubt that Greenland and the major northern archipelagos can serve as a great introduction to the environment and magnificence of the Arctic. The book uses the islands of the Arctic to give a good introduction to what the Arctic environment is all about. The first chapter sets the stage with an overview of the geography of the Arctic islands, and this is followed by chapters that cover many key aspects of the Arctic: the geology (origins), weather and climate, glaciers, ice sheets, sea ice, permafrost and other frozen ground issues, coasts, rivers, lakes, animals, people, and environmental impacts. The material is pitched at a level well suited for the interested layperson, but the book will also appeal to those who study the science of the Arctic.

  7. Approaching a Postcolonial Arctic

    DEFF Research Database (Denmark)

    Jensen, Lars

    2016-01-01

    This article explores different postcolonially configured approaches to the Arctic. It begins by considering the Arctic as a region, an entity, and how the customary political science informed approaches are delimited by their focus on understanding the Arctic as a region at the service...... of the contemporary neoliberal order. It moves on to explore how different parts of the Arctic are inscribed in a number of sub-Arctic nation-state binds, focusing mainly on Canada and Denmark. The article argues that the postcolonial can be understood as a prism or a methodology that asks pivotal questions to all...... approaches to the Arctic. Yet the postcolonial itself is characterised by limitations, not least in this context its lack of interest in the Arctic, and its bias towards conventional forms of representation in art. The article points to the need to develop a more integrated critique of colonial and neo...

  8. [Effects of Chinese herbs for cool-moistening and freeing collaterals on serum gastrin and surface electrogastrogram in patients of diabetes mellitus with gastroparesis].

    Science.gov (United States)

    Rong, Shi-ling; Li, Dian-gui; Fan, Hong-mei; Zheng, Yanping

    2004-11-01

    To explore the effect of Chinese herbs (CH) for cool-moistening and freeing collaterals on gastro-dynamic disturbance in patients of diabetes mellitus type 2 with gastroparesis (DM-GP). Fifty-three patients of DM-GP were enrolled and treated with CH (n = 28) and Cisapride (n = 25) respectively for 4 weeks, the changes of gastrin and electro-gastrogram (EGG) before and after treatment were observed. After treatment, the EGG improved significantly, showing the rhythm significantly improved, and level of serum gastrin lowered significantly, as compared with those before treatment, the difference was significant (P<0.01), but insignificant difference was found between the two groups. Fifteen patients in each group were followed-up afar stopping medication for 3 months, recurrence occurred in 1 patient of CH treated group, and 2 patients of Cisapride treated group. No adverse reaction was found in the rest patients. CH could obviously improve the gastro-intestinal motility and hormones abnormality.

  9. Multisensor Observations of the Lifecycles of Propagating Tropical Convective Systems: Horizontal and Vertical Structure, Diabatic Heating and Moistening, and Relationship to Environmental Parameters

    Science.gov (United States)

    Elsaesser, G.; Li, Y.; Kummerow, C. D.; Carbone, R. E.

    2013-12-01

    Tropical oceanic convective systems are identified and tracked through use of the CMORPH high-resolution rainfall product. The composite areal coverage of rainfall (provided by TRMM PR and CMORPH), convective/stratiform ratio (from TRMM PR), vertical extent of the raining system (TRMM PR) and the diabatic heating and moistening tendencies (Q1-QR, Q2 from the Spectral Latent Heating Algorithm product) are all quantified, as a function of both system lifecycle stage and system longevity. System longevity is shown to have strong relationships with environmental shear and humidity. The composite changes in total precipitable water (TPW) and SST (from the GHRSST product) along the paths of the systems are discussed, both as a function of system stage and longevity. Unlike the composite convective events, individual systems undergo both systematic and random variations in terms of convective organization, surface rainfall characteristics, and propagation direction as their lifecycle proceeds. These variations are investigated as a function of varying environmental shear along the path of system (provided from NCEP re-analysis), the distribution of water vapor surrounding the system (from AIRS Version-6 0.25-degree product), and newly derived QuikSCAT-based 'triggering energy' (often associated with convergence zones at the edges of large cold pools) that is a function of both the system in question as well as near-vicinity convection.

  10. 装载流程再造在降低灭菌器械湿包发生中的作用%Effect of packaging flowchart on reduction of moistening packets by sterilizers

    Institute of Scientific and Technical Information of China (English)

    梁雅; 王凯; 陈梅芳; 肖艳文

    2012-01-01

    目的 探讨装载流程再造在降低灭菌器械湿包发生中的作用效果.方法 选择2010年10月~2011年1月在本消毒供应中心消毒的3850件纸塑包装的医疗器械包为对照组,2011年2~4月的4050件纸塑包装的医疗器械包为实验组.器械进行灭菌时对照组采用常规装载方法,实验组采用装载流程再造.比较两组湿包发生情况的差异.结果 实验组发生湿包有57件(1.41%),对照组有153件(3.97%),两组比较,x2=50.248,P<0.05,差异具有统计学意义,实验组湿包发生率较对照组低.结论 装载流程再造可减少器械灭菌后湿包现象的发生.%Objective To study the effect of standardized packaging flowchart on the reduction of moistening packets by sterilizers. Methods 3 850 paper-plastic packages of metal medical instruments in the sterilization and supply center from October 2010 to April 2011 was set as the control group and another 4050 ones from October 2010 to January 2011 as the experiment group. The routine packaging was used in the control group, and the reconstructed flowchart was used in the experiment group. The two groups were compared in moistening packages by sterilizers. Results In the experiment group, 57 packages were moistened, accounting for 1.41%. In the control, 153 packages were moistened, accounting for 3.98%. The incidence of moistening packages was significantly lower in experiment group, compared with conventional method (X2 = 50.248, P< 0.05). Conclusions The reconstructed flowchart for packaging can be effective in reducing the incidence of moistening packages.

  11. Can a Human-Induced Climate Disaster be Avoided?

    Science.gov (United States)

    Watson, R.

    2012-12-01

    Emissions of greenhouse gases (GHG) are one of the greatest threats to our future prosperity. World emissions are currently around 50 billion tonnes of carbon dioxide-equivalent per annum and are growing rapidly. Atmospheric concentrations of GHG emissions in the atmosphere have increased, to over 400ppm of CO2e today, even after taking the offsetting radiative effects of aerosols into account, and are increasing at a rate of around 2.5ppm per year. The world's current lack of "adequate" commitments to reduce emissions are consistent with at least a 3oC rise (50-50 chance) in temperature: a temperature not seen on the planet for around 3 million years, with serious risks of 5oC rise: a temperature not seen on the planet for around 30 million years. So what are the implications of a 3-5oC rise in temperature, with associated changes in, rising sea levels, retreating mountain glaciers, melting of the Greenland ice cap, shrinking Arctic Sea ice, especially in summer, increasing frequency of extreme weather events, such as heat waves, floods, and droughts, and intensification of cyclonic events, such as hurricanes in the Atlantic. Even a 2oC increase in mean surface temperatures will adversely affect freshwater, food and fiber, natural ecosystems, coastal systems and low-lying areas, human health and social systems, especially in developing countries. The impacts of 3-5oC will be extensive, predominantly negative, undermine development and poverty alleviation goals and cut across most sectors. To address human-induced climate change requires a transition to a low carbon economy, which will require rapid technological evolution in the efficiency of energy use, environmentally sound low-carbon renewable energy sources and carbon capture and storage. The longer we wait to transition to a low carbon economy the more we are locked into a high carbon energy system with consequent environmental damage to ecological and socio-economic systems. Unfortunately the political will

  12. Arctic tipping points

    OpenAIRE

    Smolkova, Valentina

    2015-01-01

    The Arctic is warming much faster than the entire planet, and this causes severe melting of sea ice. However, the climate of different regions of the Earth is interconnected, and changes in the amount of ice in the Arctic can dramatically affect the climate across the whole planet. Some scientists claim that a possible tipping point is the event of the ice-free Arctic Ocean in summer. Certain predictions point towards ice-free Arctic summers around the year 2050, whereas others pre- dict this...

  13. Arctic wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, E. [Kemijoki Oy (Finland); Holttinen, H.; Marjaniemi, M. [VTT Energy, Espoo (Finland); Tammelin, B. [Finnish Meteorological Institute, Helsinki (Finland)

    1998-12-31

    Arctic wind energy research was aimed at adapting existing wind technologies to suit the arctic climatic conditions in Lapland. Project research work included meteorological measurements, instrument development, development of a blade heating system for wind turbines, load measurements and modelling of ice induced loads on wind turbines, together with the development of operation and maintenance practices in arctic conditions. As a result the basis now exists for technically feasible and economically viable wind energy production in Lapland. New and marketable products, such as blade heating systems for wind turbines and meteorological sensors for arctic conditions, with substantial export potential, have also been developed. (orig.)

  14. Global View of the Arctic Ocean

    Science.gov (United States)

    2000-01-01

    -lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images. 'We can see large cracks in the ice cover, where most ice grows, ' said Kwok. 'These cracks are much longer than previously thought, some as long as 2,000 kilometers (1,200 miles),' Kwok continued. 'If the ice is thinning due to warming, we'll expect to see more of these long cracks over the Arctic Ocean. 'Scientists believe this is one of the most significant breakthroughs in the last two decades of ice research. 'We are now in a position to better understand the sea ice cover and the role of the Arctic Ocean in global climate change, ' said Kwok.Radar can see through clouds and any kind of weather system, day or night, and as the Arctic regions are usually cloud-covered and subject to long, dark winters, radar is proving to be extremely useful. However, compiling these data into extremely detailed pictures of the Arctic is a challenging task. 'This is truly a major innovation in terms of the quantities of data being processed and the novelty of the methods being used, ' said Verne Kaupp, director of the Alaska SAR Facility at the University of Alaska, Fairbanks.The mission is a joint project between JPL, the Alaska SAR Facility, and the Canadian Space Agency. Launched by NASA in 1995, the Radarsat satellite is operated by the Canadian Space Agency. JPL manages the Sea Ice Thickness Derived From High Resolution Radar Imagery project for NASA's Earth Science Enterprise, Washington, DC. The Earth Science Enterprise is dedicated to studying how natural and human-induced changes affect our global environment.

  15. White Arctic vs. Blue Arctic: Making Choices

    Science.gov (United States)

    Pfirman, S. L.; Newton, R.; Schlosser, P.; Pomerance, R.; Tremblay, B.; Murray, M. S.; Gerrard, M.

    2015-12-01

    As the Arctic warms and shifts from icy white to watery blue and resource-rich, tension is arising between the desire to restore and sustain an ice-covered Arctic and stakeholder communities that hope to benefit from an open Arctic Ocean. If emissions of greenhouse gases to the atmosphere continue on their present trend, most of the summer sea ice cover is projected to be gone by mid-century, i.e., by the time that few if any interventions could be in place to restore it. There are many local as well as global reasons for ice restoration, including for example, preserving the Arctic's reflectivity, sustaining critical habitat, and maintaining cultural traditions. However, due to challenges in implementing interventions, it may take decades before summer sea ice would begin to return. This means that future generations would be faced with bringing sea ice back into regions where they have not experienced it before. While there is likely to be interest in taking action to restore ice for the local, regional, and global services it provides, there is also interest in the economic advancement that open access brings. Dealing with these emerging issues and new combinations of stakeholders needs new approaches - yet environmental change in the Arctic is proceeding quickly and will force the issues sooner rather than later. In this contribution we examine challenges, opportunities, and responsibilities related to exploring options for restoring Arctic sea ice and potential pathways for their implementation. Negotiating responses involves international strategic considerations including security and governance, meaning that along with local communities, state decision-makers, and commercial interests, national governments will have to play central roles. While these issues are currently playing out in the Arctic, similar tensions are also emerging in other regions.

  16. Fault analysis and processing of moistened metal oxide surge arresters%一起金属氧化物避雷器故障分析与处理

    Institute of Scientific and Technical Information of China (English)

    晏桂林; 龚宁; 张志权; 杨兴华

    2013-01-01

    The working principle of metal oxide surge arresters was described, and some of its fault detection methods were outlined. For a power plant with a 220 kV metal oxide arrester defect due to abnormal discharge current, the preliminary determination of fault nature was taken followed by promptly quitting running by the diagnostic method of resistive current testing, infrared imaging detection combined with outages routine testing. According to the dismantling of the returned defective arrester, the defect caused by lightning arrester moisture was found out, and the moistened cause of the arrester was further analyzed with the structural component.%简述了金属氧化物避雷器的工作原理,并概述了其故障检测的一些方法。针对某电厂一起220 kV金属氧化物避雷器泄流电流异常的缺陷,采用对避雷器进行带电阻性电流测试、红外线成像检测及停电常规试验相结合的诊断方法,初步判定了故障性质和故障部位。通过对退运缺陷避雷器的拆解,发现缺陷是因避雷器受潮引起,并从故障构件结构入手分析了发生受潮的原因。

  17. Russia in the Arctic

    Science.gov (United States)

    2011-07-01

    Jakobson , Linda, “China prepares for an ice-free Arctic,” SIPRI Insights on Peace and Security, No. 2010/2, March 2010, Stockholm International Peace...Governance, October 9, 2008. 23. Linda Jakobson , “China prepares for an ice-free Arctic,” SIPRI Insights on Peace and Security, No. 2010/2

  18. Ice-Free Arctic Ocean?

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    The current warming trends in the Arctic may shove the Arctic system into a seasonally ice-free state not seen for more than one million years, according to a new report. The melting is accelerating, and researchers were unable to identify any natural processes that might slow the deicing of the Arctic. "What really makes the Arctic different…

  19. Arctic Sea Level Reconstruction

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    Reconstruction of historical Arctic sea level is very difficult due to the limited coverage and quality of tide gauge and altimetry data in the area. This thesis addresses many of these issues, and discusses strategies to help achieve a stable and plausible reconstruction of Arctic sea level from...... 1950 to today.The primary record of historical sea level, on the order of several decades to a few centuries, is tide gauges. Tide gauge records from around the world are collected in the Permanent Service for Mean Sea Level (PSMSL) database, and includes data along the Arctic coasts. A reasonable...... amount of data is available along the Norwegian and Russian coasts since 1950, and most published research on Arctic sea level extends cautiously from these areas. Very little tide gauge data is available elsewhere in the Arctic, and records of a length of several decades,as generally recommended for sea...

  20. Arctic Climate Systems Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ivey, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Backus, George A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Peterson, Kara J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); van Bloemen Waanders, Bart G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Desilets, Darin Maurice [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reinert, Rhonda Karen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    This study began with a challenge from program area managers at Sandia National Laboratories to technical staff in the energy, climate, and infrastructure security areas: apply a systems-level perspective to existing science and technology program areas in order to determine technology gaps, identify new technical capabilities at Sandia that could be applied to these areas, and identify opportunities for innovation. The Arctic was selected as one of these areas for systems level analyses, and this report documents the results. In this study, an emphasis was placed on the arctic atmosphere since Sandia has been active in atmospheric research in the Arctic since 1997. This study begins with a discussion of the challenges and benefits of analyzing the Arctic as a system. It goes on to discuss current and future needs of the defense, scientific, energy, and intelligence communities for more comprehensive data products related to the Arctic; assess the current state of atmospheric measurement resources available for the Arctic; and explain how the capabilities at Sandia National Laboratories can be used to address the identified technological, data, and modeling needs of the defense, scientific, energy, and intelligence communities for Arctic support.

  1. Arctic ice management

    Science.gov (United States)

    Desch, Steven J.; Smith, Nathan; Groppi, Christopher; Vargas, Perry; Jackson, Rebecca; Kalyaan, Anusha; Nguyen, Peter; Probst, Luke; Rubin, Mark E.; Singleton, Heather; Spacek, Alexander; Truitt, Amanda; Zaw, Pye Pye; Hartnett, Hilairy E.

    2017-01-01

    As the Earth's climate has changed, Arctic sea ice extent has decreased drastically. It is likely that the late-summer Arctic will be ice-free as soon as the 2030s. This loss of sea ice represents one of the most severe positive feedbacks in the climate system, as sunlight that would otherwise be reflected by sea ice is absorbed by open ocean. It is unlikely that CO2 levels and mean temperatures can be decreased in time to prevent this loss, so restoring sea ice artificially is an imperative. Here we investigate a means for enhancing Arctic sea ice production by using wind power during the Arctic winter to pump water to the surface, where it will freeze more rapidly. We show that where appropriate devices are employed, it is possible to increase ice thickness above natural levels, by about 1 m over the course of the winter. We examine the effects this has in the Arctic climate, concluding that deployment over 10% of the Arctic, especially where ice survival is marginal, could more than reverse current trends of ice loss in the Arctic, using existing industrial capacity. We propose that winter ice thickening by wind-powered pumps be considered and assessed as part of a multipronged strategy for restoring sea ice and arresting the strongest feedbacks in the climate system.

  2. The Arctic Enigma

    OpenAIRE

    Kiilerich, Kasper; Christensen, Peter; Andreasen, Toke; Csende, Agnes

    2014-01-01

    This paper descripes how the Arctic Council deal with various issues in the arctic region, and how they have dealt with the recent interest in the region, following survey results suggesting there might be large deposits of natural gas, oil and minerals. The goal of the research is to look into how they deal with the rising issues in the arctic and if they live up to the Ottawa delcaration that was the birth of the AC. Our findings showed radically different results depending on t...

  3. Arctic Aerosols and Sources

    DEFF Research Database (Denmark)

    Nielsen, Ingeborg Elbæk

    2017-01-01

    winter and spring explained by expansion of the polar dome enabling long-range transport of aerosols from source regions outside the Arctic. This phenomenon is better known as the Arctic haze. Contrary, the summer and fall concentrations were lower due to the retreat of the polar dome. These seasonal...... species. The aerosol concentration decreased during spring as the Arctic haze leveled off. A source apportionment analysis showed that three factors were contributing to organic aerosols. A hydrocarbon-like organic aerosol factor was assigned to fossil fuel combustion and a second factor, less oxygenated...

  4. Encyclopedia of the Arctic

    National Research Council Canada - National Science Library

    Nuttall, M

    2005-01-01

    ..., physical processes, life sciences, and environmental change. This work is the result of over 375 international scholars and writers in all fields and relate to the eight Arctic countries: Canada, USA (Alaska), Greenland (Denmark...

  5. Arctic_Bathymetry

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Models project the Arctic Ocean will become undersaturated with respect to carbonate minerals in the next decade. Recent field results indicate parts may already be...

  6. Arctic_Bathymetry

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Models project the Arctic Ocean will become undersaturated with respect to carbonate minerals in the next decade. Recent field results indicate parts may already be...

  7. Arctic Bathymetry (batharcst)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The digitally compiled map includes geology, oil and gas field centerpoints, and geologic provinces of the Arctic (North Pole area encircled by 640 N Latitude). The...

  8. Arctic Geology (geoarcst)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The digitally compiled map includes geology, oil and gas field centerpoints, and geologic provinces of the Arctic (North Pole area encircled by 640 N Latitude). The...

  9. Arctic survey, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey and game patrol conducted to twelve villages in the Arctic from April 24 to May 2 1957. The report covers animals take for income and...

  10. Arctic Collaborative Environment (ACE)

    Science.gov (United States)

    2012-08-01

    distribution is unlimited. Key Data Requirements • Sea Ice – Location: Area, Onset, Growth, Drift, and Decay – Characterization: % Coverage, Thickness...Cloud ACE Developmental Server hosted at UAHuntsville ACE User Community Public Internet Tailored Ice Product Generation (NIC) Arctic Research...distribution is unlimited. Arctic Map 26 July 2012 13 Multi-sensor Analyzed Sea Ice Extent; National Data Buoy Center DISTRIBUTION STATEMENT A

  11. Arctic freshwater synthesis: Introduction

    Science.gov (United States)

    Prowse, T.; Bring, A.; Mârd, J.; Carmack, E.

    2015-11-01

    In response to a joint request from the World Climate Research Program's Climate and Cryosphere Project, the International Arctic Science Committee, and the Arctic Council's Arctic Monitoring and Assessment Program, an updated scientific assessment has been conducted of the Arctic Freshwater System (AFS), entitled the Arctic Freshwater Synthesis (AFSΣ). The major reason for joint request was an increasing concern that changes to the AFS have produced, and could produce even greater, changes to biogeophysical and socioeconomic systems of special importance to northern residents and also produce extra-Arctic climatic effects that will have global consequences. Hence, the key objective of the AFSΣ was to produce an updated, comprehensive, and integrated review of the structure and function of the entire AFS. The AFSΣ was organized around six key thematic areas: atmosphere, oceans, terrestrial hydrology, terrestrial ecology, resources and modeling, and the review of each coauthored by an international group of scientists and published as separate manuscripts in this special issue of Journal of Geophysical Research-Biogeosciences. This AFSΣ—Introduction reviews the motivations for, and foci of, previous studies of the AFS, discusses criteria used to define the domain of the AFS, and details key characteristics of the definition adopted for the AFSΣ.

  12. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    OpenAIRE

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-01-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the p...

  13. Generation of human induced pluripotent stem cells from dermal fibroblasts

    OpenAIRE

    2008-01-01

    The generation of patient-specific pluripotent stem cells has the potential to accelerate the implementation of stem cells for clinical treatment of degenerative diseases. Technologies including somatic cell nuclear transfer and cell fusion might generate such cells but are hindered by issues that might prevent them from being used clinically. Here, we describe methods to use dermal fibroblasts easily obtained from an individual human to generate human induced pluripotent stem (iPS) cells by ...

  14. Arctic Rabies – A Review

    Directory of Open Access Journals (Sweden)

    Prestrud Pål

    2004-03-01

    Full Text Available Rabies seems to persist throughout most arctic regions, and the northern parts of Norway, Sweden and Finland, is the only part of the Arctic where rabies has not been diagnosed in recent time. The arctic fox is the main host, and the same arctic virus variant seems to infect the arctic fox throughout the range of this species. The epidemiology of rabies seems to have certain common characteristics in arctic regions, but main questions such as the maintenance and spread of the disease remains largely unknown. The virus has spread and initiated new epidemics also in other species such as the red fox and the racoon dog. Large land areas and cold climate complicate the control of the disease, but experimental oral vaccination of arctic foxes has been successful. This article summarises the current knowledge and the typical characteristics of arctic rabies including its distribution and epidemiology.

  15. Arctic dimension of global warming

    Directory of Open Access Journals (Sweden)

    G. V. Alekseev

    2014-01-01

    Full Text Available A brief assessment of the global warming in the Arctic climate system with the emphasis on sea ice is presented. The Arctic region is coupled to the global climate system by the atmosphere and ocean circulation that providesa major contribution to the Arctic energy budget. On this basis using of special indices it is shown that amplification of warming in the Arctic is associated with the increasing of meridional heat transport from the low latitudes.

  16. Acquatorialities of the Arctic Region

    DEFF Research Database (Denmark)

    Harste, Gorm

    2013-01-01

    In order to describe the Arctic system I propose using a concept functionally equivalent to territoriality, namely aquatoriality. Whether communicating about territoriality or aquatoriality, concepts and delimitations are both contingent to forms of communication systems. I will distinguish betwe...... coding of the Arctic. These codes could then appear structurally coupled to a political system that in an organizational way appears in the Arctic Council...

  17. More Arctic research needed

    Science.gov (United States)

    Bush, Susan

    The desire to achieve a balance between Arctic and Antarctic study was the message of the Senate Committee on Commerce, Science, and Transportation, which heard testimony on the need for more Arctic research on April 24. Ted Stevens (R-Alaska) noted that since 1986, study in the area has not increased as the National Science Foundation has claimed, but rather, owing to inflation, has merely kept pace. Robert Correll, assistant director of geosciences at NSF and chair of the Interagency Arctic Oceans Working Group, gave several reasons why the Arctic is an important area for study by the scientific community. Its unique environment, he said, makes it a natural laboratory. And due to its environmental sensitivity, it may provide one of the earliest indicators of global climate change. Also, its geographic location makes it a “window on space,” some of the world's largest mineral and petroleum resources are in the Arctic, and the region has great strategic and military importance.

  18. Arctic security and Norway

    Energy Technology Data Exchange (ETDEWEB)

    Tamnes, Rolf

    2013-03-01

    Global warming is one of the most serious threats facing mankind. Many regions and countries will be affected, and there will be many losers. The earliest and most intense climatic changes are being experienced in the Arctic region. Arctic average temperature has risen at twice the rate of the global average in the past half century. These changes provide an early indication for the world of the environmental and societal significance of global warming. For that reason, the Arctic presents itself as an important scientific laboratory for improving our understanding of the causes and patterns of climate changes. The rapidly rising temperature threatens the Arctic ecosystem, but the human consequences seem to be far less dramatic there than in many other places in the world. According to the U.S. National Intelligence Council, Russia has the potential to gain the most from increasingly temperate weather, because its petroleum reserves become more accessible and because the opening of an Arctic waterway could provide economic and commercial advantages. Norway might also be fortunate. Some years ago, the Financial Times asked: #Left Double Quotation Mark#What should Norway do about the fact that global warming will make their climate more hospitable and enhance their financial situation, even as it inflicts damage on other parts of the world?#Right Double Quotation Mark#(Author)

  19. 浅析“肾苦燥,急食辛以润之”%A brief analysis of “The kidney tends to suffer from dryness,which can be moistened by pungent flavor ”

    Institute of Scientific and Technical Information of China (English)

    吕艳; 刘微英; 李晓君

    2015-01-01

    “The kidney tends to suffer from dryness,which can be moistened by pungent flavor”comes from Discussion on the Association of the Visceral Qi with the Four Seasons of Plain Questions.In the au-thor’s view,“the dryness of kidney”is the pathological condition which is caused by the deficiency of kidney yang,failing in transformation of qi,so the fluid in the body cannot be generated and transported normally.The pungent flavor can contribute to the running of qi and opening the barrier of the skin,so that it can scatter enough water to moisten the dryness due to poor running of qi and body fluid natural transportation obstacle.%“肾苦燥,急食辛以润之”出自《素问·脏气法时论篇》。“肾燥”,是肾阳虚蒸腾气化失常,津液不得布散、运行不畅所致的病理状态。辛味(药物等)可以通达气机,宣发腠理,布津敷液,以治气机运行不畅、津液输布障碍之“燥”。

  20. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments. The CBMP includes an international...... on developing and implementing long-term plans for monitoring the integrity of Arctic biomes: terrestrial, marine, freshwater, and coastal (under development) environments. The CBMP Terrestrial Expert Monitoring Group (CBMP-TEMG) has developed the Arctic Terrestrial Biodiversity Monitoring Plan (CBMP......-Terrestrial Plan/the Plan) as the framework for coordinated, long-term Arctic terrestrial biodiversity monitoring. The goal of the CBMP-Terrestrial Plan is to improve the collective ability of Arctic traditional knowledge (TK) holders, northern communities, and scientists to detect, understand and report on long...

  1. Globalising the Arctic Climate:

    DEFF Research Database (Denmark)

    Corry, Olaf

    2017-01-01

    This chapter uses an object-oriented approach to explore how the Arctic is being constituted as an object of global governance within an emerging ‘global polity’, partly through geoengineering plans and political visions ('imaginaries'). It suggests that governance objects—the socially constructe...... on world politics. The emergence of the Arctic climate as a potential target of governance provides a case in point. The Arctic climate is becoming globalised, pushing it up the political agenda but drawing it away from its local and regional context.......This chapter uses an object-oriented approach to explore how the Arctic is being constituted as an object of global governance within an emerging ‘global polity’, partly through geoengineering plans and political visions ('imaginaries'). It suggests that governance objects—the socially constructed...... targets of political operations and contestations—are not simple ‘issues’ or ‘problems’ given to actors to deal with. Governance-objects emerge and are constructed through science, technology and politics, and rather than slotting neatly into existing structures, they have their own structuring effects...

  2. Communicating Arctic Change (Invited)

    Science.gov (United States)

    Serreze, M.

    2009-12-01

    Nowhere on the planet are emerging signals of climate change more visible than in the Arctic. Rapid warming, a quickly shrinking summer sea ice cover, and thawing permafrost, will have impacts that extend beyond the Arctic and may reverberate around the globe. The National Snow and Ice Data Center (NSIDC) of the University of Colorado has taken a leading role in trying to effectively communicate the science and importance of Arctic change. Our popular “Sea Ice News and Analysis” web site tracks the Arctic’s shrinking ice cover and provides scientific analysis with language that is accurate yet accessible to a wide audience. Our Education Center provides accessible information on all components of the Earth’s cryosphere, the changes being seen, and how scientists conduct research. A challenge faced by NSIDC is countering the increasing level of confusion and misinformation regarding Arctic and global change, a complex problem that reflects the low level of scientific literacy by much of the public, the difficulties many scientists face in communicating their findings in accurate but understandable terms, and efforts by some groups to deliberately misrepresent and distort climate change science. This talk will outline through examples ways in which NSIDC has been successful in science communication and education, as well as lessons learned from failures.

  3. Arctic Sea Ice

    Science.gov (United States)

    Stroeve, J. C.; Fetterer, F.; Knowles, K.; Meier, W.; Serreze, M.; Arbetter, T.

    2004-12-01

    Of all the recent observed changes in the Arctic environment, the reduction of sea ice cover stands out most prominantly. Several independent analysis have established a trend in Arctic ice extent of -3% per decade from the late 1970s to the late 1990s, with a more pronounced trend in summer. The overall downward trend in ice cover is characterized by strong interannual variability, with a low September ice extent in one year typically followed by recovery the next September. Having two extreme minimum years, such as what was observed in 2002 and 2003 is unusual. 2004 marks the third year in a row of substantially below normal sea ice cover in the Arctic. Early summer 2004 appeared unusual in terms of ice extent, with May a record low for the satellite period (1979-present) and June also exhibiting below normal ice extent. August 2004 extent is below that of 2003 and large reductions in ice cover are observed once again off the coasts of Siberia and Alaska and the Greenland Sea. Neither the 2002 or 2003 anomaly appeared to be strongly linked to the positive phase of the Arctic Oscillation (AO) during the preceding winter. Similarly, the AO was negative during winter 2003/2004. In the previous AO framework of Rigor et al (2002), a positive winter AO implied preconditioning of the ice cover to extensive summer decay. In this hypothesis, the AO does not explain all aspects of the recent decline in Arctic ice cover, such as the extreme minima of 2002, 2003 and 2004. New analysis by Rigor and Wallace (2004) suggest that the very positive AO state from 1989-1995 can explain the recent sea ice minima in terms of changes in the Arctic surface wind field associated with the previous high AO state. However, it is also reasonable to expect that a general decrease in ice thickness accompanying warming would manifest itself as greater sensitivity of the ice pack to wind forcings and albedo feedbacks. The decrease in multiyear ice and attendant changes in ice thickness

  4. The Arctic Circle

    Science.gov (United States)

    McDonald, Siobhan

    2016-04-01

    My name is Siobhan McDonald. I am a visual artist living and working in Dublin. My studio is based in The School of Science at University College Dublin where I was Artist in Residence 2013-2015. A fascination with time and the changeable nature of landmass has led to ongoing conversations with scientists and research institutions across the interweaving disciplines of botany, biology and geology. I am developing a body of work following a recent research trip to the North Pole where I studied the disappearing landscape of the Arctic. Prompted by my experience of the Arctic shelf receding, this new work addresses issues of the instability of the earth's materiality. The work is grounded in an investigation of material processes, exploring the dynamic forces that transform matter and energy. This project combines art and science in a fascinating exploration of one of the Earth's last relatively untouched wilderness areas - the High Arctic to bring audiences on journeys to both real and artistically re-imagined Arctic spaces. CRYSTALLINE'S pivotal process is collaboration: with The European Space Agency; curator Helen Carey; palaeontologist Prof. Jenny McElwain, UCD; and with composer Irene Buckley. CRYSTALLINE explores our desire to make corporeal contact with geological phenomena in Polar Regions. From January 2016, in my collaboration with Jenny McElwain, I will focus on the study of plants and atmospheres from the Arctic regions as far back as 400 million years ago, to explore the essential 'nature' that, invisible to the eye, acts as imaginary portholes into other times. This work will be informed by my arctic tracings of sounds and images recorded in the glaciers of this disappearing frozen landscape. In doing so, the urgencies around the tipping of natural balances in this fragile region will be revealed. The final work will emerge from my forthcoming residency at the ESA in spring 2016. Here I will conduct a series of workshops in ESA Madrid to work with

  5. Tsunami in the Arctic

    Science.gov (United States)

    Kulikov, Evgueni; Medvedev, Igor; Ivaschenko, Alexey

    2017-04-01

    The severity of the climate and sparsely populated coastal regions are the reason why the Russian part of the Arctic Ocean belongs to the least studied areas of the World Ocean. In the same time intensive economic development of the Arctic region, specifically oil and gas industry, require studies of potential thread natural disasters that can cause environmental and technical damage of the coastal and maritime infrastructure of energy industry complex (FEC). Despite the fact that the seismic activity in the Arctic can be attributed to a moderate level, we cannot exclude the occurrence of destructive tsunami waves, directly threatening the FEC. According to the IAEA requirements, in the construction of nuclear power plants it is necessary to take into account the impact of all natural disasters with frequency more than 10-5 per year. Planned accommodation in the polar regions of the Russian floating nuclear power plants certainly requires an adequate risk assessment of the tsunami hazard in the areas of their location. Develop the concept of tsunami hazard assessment would be based on the numerical simulation of different scenarios in which reproduced the hypothetical seismic sources and generated tsunamis. The analysis of available geological, geophysical and seismological data for the period of instrumental observations (1918-2015) shows that the highest earthquake potential within the Arctic region is associated with the underwater Mid-Arctic zone of ocean bottom spreading (interplate boundary between Eurasia and North American plates) as well as with some areas of continental slope within the marginal seas. For the Arctic coast of Russia and the adjacent shelf area, the greatest tsunami danger of seismotectonic origin comes from the earthquakes occurring in the underwater Gakkel Ridge zone, the north-eastern part of the Mid-Arctic zone. In this area, one may expect earthquakes of magnitude Mw ˜ 6.5-7.0 at a rate of 10-2 per year and of magnitude Mw ˜ 7.5 at a

  6. Discriminating Characteristics of Tectonic and Human-Induced Seismicity

    Science.gov (United States)

    Zaliapin, I. V.; Ben-Zion, Y.

    2015-12-01

    We analyze statistical features of background and clustered subpopulations of earthquakes in different regions in an effort to distinguish between human-induced and natural seismicity. Analysis of "end-member" areas known to be dominated by human-induced earthquakes (the Geyser geothermal field in northern California and TauTona gold mine in South Africa) and regular tectonic activity (the San Jacinto fault zone in southern California and Coso region excluding the Coso geothermal field in eastern central California) reveals several distinguishing characteristics. Induced seismicity is shown to have (i) higher rate of background events (both absolute and relative to the total rate), (ii) faster temporal offspring decay, (iii) higher intensity of repeating events, (iv) larger proportion of small clusters, and (v) larger spatial separation between parent and offspring, compared to regular tectonic activity. These differences also successfully discriminate seismicity within the Coso and Salton Sea geothermal fields in California before and after the expansion of geothermal production during the 1980s.

  7. Some discussions on Arctic vortex

    Institute of Scientific and Technical Information of China (English)

    Li Hai; Sun Lantao; Wu Huiding; Li Xiang

    2006-01-01

    The Arctic vortex is a persistent large-scale cyclonic circulation in the middle and upper troposphere and the stratosphere. Its activity and variation control the semi-permanent active centers of Pan-Arctic and the short-time cyclone activity in the subarctic areas. Its strength variation, which directly relates to the atmosphere, ocean, sea ice and ecosystem of the Arctic, can affect the lower atmospheric circulation, the weather of subarctic area and even the weather of middle latitude areas. The 2003 Chinese Second Arctic Research Expedition experienced the transition of the stratosphereic circulation from a warm anticyclone to a cold cyclone during the ending period of Arctic summertime, a typical establishing process of the polar vortex circulation. The impact of the polar vortex variation on the low-level circulation has been investigated by some scientists through studying the coupling mechanisms of the stratosphere and troposphere. The impact of the Stratospheric Sudden Warming (SFW) events on the polar vortex variation was drawing people's great attention in the fifties of the last century. The Arctic Oscillation (AO) , relating to the variation of the Arctic vortex, has been used to study the impact of the Arctic vortex on climate change. The recent Arctic vortex studies are simply reviewed and some discussions on the Arctic vertex are given in the paper. Some different views and questions are also discussed.

  8. Arctic ice islands

    Energy Technology Data Exchange (ETDEWEB)

    Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.; Li, F.C.

    1988-01-01

    The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1) calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.

  9. Islands of the Arctic

    Science.gov (United States)

    Dowdeswell, Julian; Hambrey, Michael

    2002-11-01

    The Arctic islands are characterized by beautiful mountains and glaciers, in which the wildlife lives in delicate balance with its environment. It is a fragile region with a long history of exploration and exploitation that is now experiencing rapid environmental change. All of these themes are explored in Islands of the Arctic, a richly illustrated volume with superb photographs from the Canadian Arctic archipelago, Greenland, Svalbard and the Russian Arctic. It begins with the various processes shaping the landscape: glaciers, rivers and coastal processes, the role of ice in the oceans and the weather and climate. Julian Dowdeswell and Michael Hambrey describe the flora and fauna in addition to the human influences on the environment, from the sustainable approach of the Inuit, to the devastating damage inflicted by hunters and issues arising from the presence of military security installations. Finally, they consider the future prospects of the Arctic islands Julian Dowdeswell is Director of the Scott Polar Research Institute and Professor of Physical Geography at 0he University of Cambridge. He received the Polar Medal from Queen Elizabeth for his contributions to the study of glacier geophysics and the Gill Memorial Award from the Royal Geographical Society. He is chair of the Publications Committee of the International Glaciological Society and head of the Glaciers and Ice Sheets Division of the International Commission for Snow and Ice. Michael Hambrey is Director of the Centre for Glaciology at the University of Wales, Aberystwyth. A past recipient of the Polar Medal, he was also given the Earth Science Editors' Outstanding Publication Award for Glaciers (Cambridge University Press). Hambrey is also the author of Glacial Environments (British Columbia, 1994).

  10. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments. The CBMP includes an international...... network of scientists, conservation organizations, government agencies, Permanent Participants Arctic community experts and leaders. Using an ecosystem-based monitoring approach which includes species, ecological functions, ecosystems, their interactions, and potential drivers, the CBMP focuses...... on developing and implementing long-term plans for monitoring the integrity of Arctic biomes: terrestrial, marine, freshwater, and coastal (under development) environments. The CBMP Terrestrial Expert Monitoring Group (CBMP-TEMG) has developed the Arctic Terrestrial Biodiversity Monitoring Plan (CBMP...

  11. ESPC Regional Arctic Prediction System

    Science.gov (United States)

    2014-09-30

    the Navy the capability to conduct short-term (1 week) to extended (2 weeks) coupled weather forecasts for the Arctic region. APPROACH To...sensitivity of the Arctic weather forecast to key numerical parameters; and 5) conduct extensive validation and verification of the coupled system and...SEP 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE ESPC Regional Arctic Prediction System 5a. CONTRACT

  12. Japan’s arctic policy

    Directory of Open Access Journals (Sweden)

    Dmitry V. Streltsov

    2017-01-01

    Full Text Available Abstract: The article is devoted to the public policy of modern Japan in the Arctic. The Japanese government has put forward clear and well-specifi ed targets of the intensifi cation of Japan’s efforts in the economic development of the Arctic region. Among the priorities of the Arctic policy one should mention such areas as the development of maritime transportation, development of hydrocarbon deposits of the Arctic shelf, sea fi shing, as well as the preservation and increase of the sea bioresources.

  13. Arctic River organic matter transport

    Science.gov (United States)

    Raymond, Peter; Gustafsson, Orjan; Vonk, Jorien; Spencer, Robert; McClelland, Jim

    2016-04-01

    Arctic Rivers have unique hydrology and biogeochemistry. They also have a large impact on the Arctic Ocean due to the large amount of riverine inflow and small ocean volume. With respect to organic matter, their influence is magnified by the large stores of soil carbon and distinct soil hydrology. Here we present a recap of what is known of Arctic River organic matter transport. We will present a summary of what is known of the ages and sources of Arctic River dissolved and particulate organic matter. We will also discuss the current status of what is known about changes in riverine organic matter export due to global change.

  14. The Arctic Circle Revisited

    CERN Document Server

    Colomo, F

    2007-01-01

    The problem of limit shapes in the six-vertex model with domain wall boundary conditions is addressed by considering a specially tailored bulk correlation function, the emptiness formation probability. A closed expression of this correlation function is given, both in terms of certain determinant and multiple integral, which allows for a systematic treatment of the limit shapes of the model for full range of values of vertex weights. Specifically, we show that for vertex weights corresponding to the free-fermion line on the phase diagram, the emptiness formation probability is related to a one-matrix model with a triple logarithmic singularity, or Triple Penner model. The saddle-point analysis of this model leads to the Arctic Circle Theorem, and its generalization to the Arctic Ellipses, known previously from domino tilings.

  15. Research with Arctic peoples

    DEFF Research Database (Denmark)

    Smith, H Sally; Bjerregaard, Peter; Chan, Hing Man

    2006-01-01

    of environmental and health issues that are unique to the Arctic regions, and research exploring these issues offers significant opportunities, as well as challenges. On July 28-29, 2004, the National Heart, Lung, and Blood Institute and the Canadian Institutes of Health Research co-sponsored a working group...... entitled "Research with Arctic Peoples: Unique Research Opportunities in Heart, Lung, Blood and Sleep Disorders". The meeting was international in scope with investigators from Greenland, Iceland and Russia, as well as Canada and the United States. Multiple health agencies from Canada and the United States...... sent representatives. Also attending were representatives from the International Union for Circumpolar Health (IUCH) and the National Indian Health Board. The working group developed a set of ten recommendations related to research opportunities in heart, lung, blood and sleep disorders; obstacles...

  16. International Arctic Research Programs

    Science.gov (United States)

    1989-07-01

    our re- 27 Demand for multi-disciplinary of the boreal forest zone -, should discuss the feazibility of establishing a mechanism Scientific Cooperation...interactions, very low frequency waves, auroras , and precipitation of energetic particles from the mag- netosphere. Ocean Sciences research has...vestigating the aurora phenomenon, which can have a severe impact on communications, and the dynamics of the upper atmosphere, including the arctic

  17. Disparities in Arctic Health

    Centers for Disease Control (CDC) Podcasts

    2008-02-04

    Life at the top of the globe is drastically different. Harsh climate devoid of sunlight part of the year, pockets of extreme poverty, and lack of physical infrastructure interfere with healthcare and public health services. Learn about the challenges of people in the Arctic and how research and the International Polar Year address them.  Created: 2/4/2008 by Emerging Infectious Diseases.   Date Released: 2/20/2008.

  18. Green Arctic Patrol Vessel

    Science.gov (United States)

    2011-08-01

    Search Radar (2D) Non-rotating IFF system Electro- Optical security system Naval Surface Warfare Center Carderock Division Green Arctic Patrol...Speed Endurance Modular Systems and Capabilities UUV Bluefin 21 4.93 0.53 750 kg 4,500 m 25 hours Side scan sonar, multibeam ...sensors, 256 Mb flash card USV ASV 6300 6.30 Beam: 0.65 Height: 3.50 2.0 tonnes 8 kt 96 hours @ 4 kt Multibeam , sidescan sonars, CTD

  19. Summer Arctic sea fog

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Synchronous or quasi-synchronous sea-land-air observations were conducted using advanced sea ice, atmospheric and marine instruments during China' s First Arctic Expedition. Based on the Precious data from the expedition, it was found that in the Arctic Ocean, most part of which is covered with ice or is mixed with ice, various kinds of sea fog formed such as advection fog, radiation fog and vapor fog. Each kind has its own characteristic and mechanics of creation. In the southern part of the Arctic Ocean, due to the sufficient warm and wet flow there, it is favorable for advection fog to form,which is dense and lasts a long time. On ice cap or vast floating ice, due to the strong radiation cooling effect, stable radiating fog is likely to form. In floating ice area there forms vapor fog with the appearance of masses of vapor from a boiling pot, which is different from short-lasting land fog. The study indicates that the reason why there are many kinds of sea fog form in the Arctic Ocean is because of the complicated cushion and the consequent sea-air interaction caused by the sea ice distribution and its unique physical characteristics. Sea fog is the atmospheric phenomenon of sea-air heat exchange. Especially, due to the high albedo of ice and snow surface, it is diffcult to absorb great amount of solar radiation during the polar days. Besides, ice is a poor conductor of heat; it blocks the sea-air heat exchange.The sea-air exchange is active in floating ice area where the ice is broken. The sea sends heat to the atmosphere in form of latent heat; vapor fog is a way of sea-air heat exchange influencing the climate and an indicator of the extent of the exchange. The study also indicates that the sea also transports heat to the atmosphere in form of sensible heat when vapor fog occurs.

  20. Biodiversity of arctic marine fishes

    DEFF Research Database (Denmark)

    Mecklenburg, Catherine W.; Møller, Peter Rask; Steinke, Dirk

    2011-01-01

    Taxonomic and distributional information on each fish species found in arctic marine waters is reviewed, and a list of families and species with commentary on distributional records is presented. The list incorporates results from examination of museum collections of arctic marine fishes dating b...

  1. Mining in the European Arctic

    NARCIS (Netherlands)

    van Dam, Kim; Scheepstra, Annette; Gille, Johan; Stępień, Adam; Koivurova, Timo

    2014-01-01

    The European Arctic is currently experiencing an upsurge in mining activities, but future developments will be highly sensitive to mineral price fluctuations. The EU is a major consumer and importer of Arctic raw materials. As the EU is concerned about the security of supply, it encourages domestic

  2. Arctic interests and policy of France

    OpenAIRE

    Yuri I. Rubinsky

    2016-01-01

    The author considers scientific, economic and political activities of France for the development and exploration of the Arctic, providing security there. Along with some other non-Arctic countries, France is not ready to accept such a situation when eight members of the Arctic Council solve Arctic problems on behalf of all mankind.

  3. AMAP Assessment 2013: Arctic Ocean acidification

    Science.gov (United States)

    2013-01-01

    This assessment report presents the results of the 2013 AMAP Assessment of Arctic Ocean Acidification (AOA). This is the first such assessment dealing with AOA from an Arctic-wide perspective, and complements several assessments that AMAP has delivered over the past ten years concerning the effects of climate change on Arctic ecosystems and people. The Arctic Monitoring and Assessment Programme (AMAP) is a group working under the Arctic Council. The Arctic Council Ministers have requested AMAP to: - produce integrated assessment reports on the status and trends of the conditions of the Arctic ecosystems;

  4. Arctic Ecosystem Integrated Survey (Arctic Eis): Marine ecosystem dynamics in the rapidly changing Pacific Arctic Gateway

    Science.gov (United States)

    Mueter, Franz J.; Weems, Jared; Farley, Edward V.; Sigler, Michael F.

    2017-01-01

    Arctic Marine Ecosystems are undergoing rapid changes associated with ice loss and surface warming resulting from human activities (IPCC, 2013). The most dramatic changes include an earlier ice retreat and a longer ice-free season, particularly on Arctic inflow shelves such as the Barents Sea in the Atlantic Arctic and the northern Bering Sea and Chukchi Sea in the Pacific Arctic, the two major gateways into the Arctic (Danielson et al., 2016; Frey et al., 2015; Serreze et al., 2007; Wood et al., 2015). The retreat of Arctic sea ice has opened access to the Arctic marine environment and its resources, particularly during summer, and among other changes has brought with it increased research activities. For the Pacific Arctic region, these activities have led to several recent compendiums examining physical, biogeochemical, and biological patterns and trends in this rapidly changing environment (Arrigo, 2015, 2016; Arrigo et al., 2014; Bluhm et al., 2010; Dunton et al., 2014; Grebmeier and Maslowski, 2014; Hopcroft and Day, 2013; Moore and Stabeno, 2015).

  5. Evaluation of human-induced vibration of continuous footbridges

    Directory of Open Access Journals (Sweden)

    El-Robaa Ahmed

    2015-01-01

    Full Text Available With the development of construction materials and the introduction of high strength steel and concrete, the human-induced vibration became a dominant criterion for the design of pedestrian bridges. Currently, longer spans and lightweight bridges have been comprised in most of design trends. This leads to lower the natural frequencies of the system which have a great effect on the dynamic performance of bridges subjected to human activities. Although the design of steel footbridges could reach the optimum level of design in terms of strength criterion, it might not reach the acceptance level for vibration condition. This will enforce the designer to choose section profiles with higher inertia to enhance stiffness of the whole system. This paper presents an overall assessment for floor vibration problem due to pedestrian induced vertical forces on continuous composite footbridges. The footfall method presented by concrete centre “CCIP-016” is adopted in this study to evaluate the response factor and acceleration of pedestrian bridges using a FEA software package “Robot Structural Analysis”.

  6. Generation of functional podocytes from human induced pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Osele Ciampi

    2016-07-01

    Full Text Available Generating human podocytes in vitro could offer a unique opportunity to study human diseases. Here, we describe a simple and efficient protocol for obtaining functional podocytes in vitro from human induced pluripotent stem cells. Cells were exposed to a three-step protocol, which induced their differentiation into intermediate mesoderm, then into nephron progenitors and, finally, into mature podocytes. After differentiation, cells expressed the main podocyte markers, such as synaptopodin, WT1, α-Actinin-4, P-cadherin and nephrin at the protein and mRNA level, and showed the low proliferation rate typical of mature podocytes. Exposure to Angiotensin II significantly decreased the expression of podocyte genes and cells underwent cytoskeleton rearrangement. Cells were able to internalize albumin and self-assembled into chimeric 3D structures in combination with dissociated embryonic mouse kidney cells. Overall, these findings demonstrate the establishment of a robust protocol that, mimicking developmental stages, makes it possible to derive functional podocytes in vitro.

  7. Translational prospects for human induced pluripotent stem cells.

    Science.gov (United States)

    Csete, Marie

    2010-07-01

    The pace of research on human induced pluripotent stem (iPS) cells is frantic worldwide, based on the enormous therapeutic potential of patient-specific pluripotent cells free of the ethical and political issues that plagued human embryonic stem cell research. iPS cells are now relatively easy to isolate from somatic cells and reprogramming can be accomplished using nonmutagenic technologies. Access to iPS cells is already paying dividends in the form of new disease-in-a-dish models for drug discovery and as scalable sources of cells for toxicology. For translation of cell therapies, the major advantage of iPS cells is that they are autologous, but for many reasons, perfect immunologic tolerance of iPS-based grafts should not be assumed. This article focuses on the functional identity of iPS cells, anticipated safety and technical issues in their application, as well as a survey of the progress likely to be realized in clinical applications in the next decade.

  8. Hematopoietic development from human induced pluripotent stem cells.

    Science.gov (United States)

    Lengerke, Claudia; Grauer, Matthias; Niebuhr, Nina I; Riedt, Tamara; Kanz, Lothar; Park, In-Hyun; Daley, George Q

    2009-09-01

    A decade of research on human embryonic stem cells (ESC) has paved the way for the discovery of alternative approaches to generating pluripotent stem cells. Combinatorial overexpression of a limited number of proteins linked to pluripotency in ESC was recently found to reprogram differentiated somatic cells back to a pluripotent state, enabling the derivation of isogenic (patient-specific) pluripotent stem cell lines. Current research is focusing on improving reprogramming protocols (e.g., circumventing the use of retroviral technology and oncoproteins), and on methods for differentiation into transplantable tissues of interest. In mouse ESC, we have previously shown that the embryonic morphogens BMP4 and Wnt3a direct blood formation via activation of Cdx and Hox genes. Ectopic expression of Cdx4 and HoxB4 enables the generation of mouse ESC-derived hematopoietic stem cells (HSC) capable of multilineage reconstitution of lethally irradiated adult mice. Here, we explore hematopoietic development from human induced pluripotent stem (iPS) cells generated in our laboratory. Our data show robust differentiation of iPS cells to mesoderm and to blood lineages, as shown by generation of CD34(+)CD45(+) cells, hematopoietic colony activity, and gene expression data, and suggest conservation of blood patterning pathways between mouse and human hematopoietic development.

  9. Assembling an Arctic Ocean Boundary Monitoring Array

    OpenAIRE

    Tsubouchi, T.

    2014-01-01

    The Arctic Ocean boundary monitoring array has been maintained over many years by six research institutes located worldwide. Our approach to Arctic Ocean boundary measurements is generating significant scientific outcomes. However, it is not always easy to access Arctic data. On the basis of our last five years’ experience of assembling pan-Arctic boundary data, and considering the success of Argo, I propose that Arctic data policy should be driven by specific scientific-based requirements. O...

  10. Arctic hydrology and meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D.L.

    1990-01-01

    During 1990, we have continued our meteorological and hydrologic data collection in support of our process-oriented research. The six years of data collected to data is unique in its scope and continuity in a North Hemisphere Arctic setting. This valuable data base has allowed us to further our understanding of the interconnections and interactions between the atmosphere/hydrosphere/biosphere/lithosphere. The increased understanding of the heat and mass transfer processes has allowed us to increase our model-oriented research efforts.

  11. Arctic Ice Studies

    Science.gov (United States)

    1993-02-01

    jFigure 1. NIfS-7 SWr imagery frou 6 July 1983 portrays variat s i ie con.centra- tion across the experiental area Figure 2. Large floes in the East...and P. T. Shaw. Particle pathways in the and by European Community Commission contract CCE CLI-083 F. Gulf Stream. Bull. Am. Meteorol. Soc.. 66, 1106...New York: Academic Press, 1981. pp. 29-62. ice in the arctic," inProc. 4th Symp. Remote Sensing of En viron., 1281 R. T. Lowry, private communication

  12. Arctic Summer Ice Processes

    Science.gov (United States)

    Holt, Benjamin

    1999-01-01

    The primary objective of this study is to estimate the flux of heat and freshwater resulting from sea ice melt in the polar seas. The approach taken is to examine the decay of sea ice in the summer months primarily through the use of spaceborne Synthetic Aperture Radar (SAR) imagery. The improved understanding of the dynamics of the melt process can be usefully combined with ice thermodynamic and upper ocean models to form more complete models of ice melt. Models indicate that more heat is absorbed in the upper ocean when the ice cover is composed of smaller rather than larger floes and when there is more open water. Over the course of the summer, floes disintegrate by physical forcing and heating, melting into smaller and smaller sizes. By measuring the change in distribution of floes together with open water over a summer period, we can make estimates of the amount of heating by region and time. In a climatic sense, these studies are intended to improve the understanding of the Arctic heat budget which can then be eventually incorporated into improved global climate models. This work has two focus areas. The first is examining the detailed effect of storms on floe size and open water. A strong Arctic low pressure storm has been shown to loosen up the pack ice, increase the open water concentration well into the pack ice, and change the distribution of floes toward fewer and smaller floes. This suggests episodic melting and the increased importance of horizontal (lateral) melt during storms. The second focus area is related to an extensive ship-based experiment that recently took place in the Arctic called Surface Heat Budget of the Arctic (SHEBA). An icebreaker was placed purposely into the older pack ice north of Alaska in September 1997. The ship served as the base for experimenters who deployed extensive instrumentation to measure the atmosphere, ocean, and ice during a one-year period. My experiment will be to derive similar measurements (floe size, open

  13. The Arctic lithosphere: an overview

    Science.gov (United States)

    Drachev, S.; Pease, V.; Stephenson, R.

    2012-04-01

    The Arctic is comprised of three deepwater oceanic basins, the Norwegian-Greenland, Eurasia, and Amerasia basins, surrounded by continental masses of the Achaean to Early Proterozoic North American, Baltica and Siberian cratons and intervening Neoproterozoic and Phanerozoic fold belts. Though the tectonic history of the Arctic continental realm spans almost three billions of years, the formation of the Arctic began with the creation of Pangaea-II supercontinent at end of Permian epoch. Between 250 and 150 Ma the Proto-Arctic was represented by the Anyui Ocean, or Angayuchum Sea - a Paleo-Pacific embayment into Pangaea II. During the Mesozoic Pangaea II was destroyed and the Anyi Ocean was isolated from the Paleo-Pacific, finally leading to the separation of Arctic Alaska-Chukchi Microcontinent from the North American side of Laurasia; the collision of this microplate with the Siberian margin occurred at ca. 125 Ma in association with the opening of the Canada Basin. The final stage of the Arctic formation took place in the Cenozoic, and was related to the propagation of the divergent Atlantic lithospheric plate boundary between North America and Baltica with the separation of the Lomonosov continental sliver from the Eurasian margin and opening of the Eurasia oceanic basin between 56 and 0 Ma. The present-day Arctic, especially its shelves and oceanic basins, is one of the least studied places on the Earth. Though we know the geology of the surrounding continental masses, there are still many questions remaining about major lithospheric divides beneath the Arctic seas, such as: • Where are the plate boundaries associated with the Amerasia Basin? • How and when did the Canada Basin open? • What was the pre-drift setting of the Chukchi Borderland? • Which tectonic processes formed the East Siberian shelves? • How and when did the major ridges in the Amerasia Basin form? • Where are the Early Tertiary plate boundaries in the Arctic? • What is the

  14. Modeling and remote sensing of human induced water cycle change

    Science.gov (United States)

    Pokhrel, Yadu N.

    2016-04-01

    The global water cycle has been profoundly affected by human land-water management especially during the last century. Since the changes in water cycle can affect the functioning of a wide range of biophysical and biogeochemical processes of the Earth system, it is essential to account for human land-water management in land surface models (LSMs) which are used for water resources assessment and to simulate the land surface hydrologic processes within Earth system models (ESMs). During the last two decades, noteworthy progress has been made in modeling human impacts on the water cycle but sufficient advancements have not yet been made, especially in representing human factors in large-scale LSMs toward integrating them into ESMs. In this study, an integrated modeling framework of continental-scale water cycle, with explicit representation of climate and human induced forces (e.g., irrigation, groundwater pumping) is developed and used to reconstruct the observed water cycle changes in the past and to attribute the observed changes to climatic and human factors. The new model builds upon two different previously developed models: a global LSM called the Human Impacts and GroundWater in the MATSIRO (HiGW-MAT) and a high-resolution regional groundwater model called the LEAF-Hydro-Flood. The model is used to retro-simulate the hydrologic stores and fluxes in close dialogue with in-situ and GRACE satellite based observations at a wide range of river basin scales around the world, with a particular focus on the changes in groundwater dynamics in northwest India, Pakistan, and the High Plains and Central Valley aquifers in the US.

  15. Human-induced trophic cascades along the fecal detritus pathway.

    Directory of Open Access Journals (Sweden)

    Elizabeth Nichols

    Full Text Available Human presence and activity in tropical forest is thought to exert top-down regulation over the various 'green-world' pathways of plant-based foodwebs. However, these effects have never been explored for the 'brown-world' pathways of fecal-detritus webs. The strong effects of humans on tropical game mammals are likely to indirectly influence fecal detritivores (including Scarabaeine dung beetles, with subsequent indirect impacts on detrivore-mediated and plant-facilitating detrital processes. Across a 380-km gradient of human influence in the western Brazilian Amazon, we conducted the first landscape-level assessment of human-induced cascade effects on the fecal detritus pathway, by coupling data on human impact, game mammal and detritivore community structure, and rate measurements of a key detritus process (i.e. dung beetle-mediated secondary seed dispersal. We found evidence that human impact indirectly influences both the diversity and biomass of fecal detritivores, but not detritivore-mediated processes. Cascade strength varied across detritivore groups defined by species' traits. We found smaller-bodied dung beetles were at higher risk of local decline in areas of human presence, and that body size was a better predictor of cascade structure than fecal resource manipulation strategy. Cascade strength was also stronger in upland, unflooded forests, than in seasonally flooded forests. Our results suggest that the impact of human activity in tropical forest on fecal-detritus food web structure is mediated by both species' traits and habitat type. Further research will be required to determine the conditions under which these cascade effects influence fecal-detritus web function.

  16. Generation of human induced pluripotent stem cells from dermal fibroblasts.

    Science.gov (United States)

    Lowry, W E; Richter, L; Yachechko, R; Pyle, A D; Tchieu, J; Sridharan, R; Clark, A T; Plath, K

    2008-02-26

    The generation of patient-specific pluripotent stem cells has the potential to accelerate the implementation of stem cells for clinical treatment of degenerative diseases. Technologies including somatic cell nuclear transfer and cell fusion might generate such cells but are hindered by issues that might prevent them from being used clinically. Here, we describe methods to use dermal fibroblasts easily obtained from an individual human to generate human induced pluripotent stem (iPS) cells by ectopic expression of the defined transcription factors KLF4, OCT4, SOX2, and C-MYC. The resultant cell lines are morphologically indistinguishable from human embryonic stem cells (HESC) generated from the inner cell mass of a human preimplantation embryo. Consistent with these observations, human iPS cells share a nearly identical gene-expression profile with two established HESC lines. Importantly, DNA fingerprinting indicates that the human iPS cells were derived from the donor material and are not a result of contamination. Karyotypic analyses demonstrate that reprogramming of human cells by defined factors does not induce, or require, chromosomal abnormalities. Finally, we provide evidence that human iPS cells can be induced to differentiate along lineages representative of the three embryonic germ layers indicating the pluripotency of these cells. Our findings are an important step toward manipulating somatic human cells to generate an unlimited supply of patient-specific pluripotent stem cells. In the future, the use of defined factors to change cell fate may be the key to routine nuclear reprogramming of human somatic cells.

  17. Human induced pluripotent stem cells on autologous feeders.

    Directory of Open Access Journals (Sweden)

    Kazutoshi Takahashi

    Full Text Available BACKGROUND: For therapeutic usage of induced Pluripotent Stem (iPS cells, to accomplish xeno-free culture is critical. Previous reports have shown that human embryonic stem (ES cells can be maintained in feeder-free condition. However, absence of feeder cells can be a hostile environment for pluripotent cells and often results in karyotype abnormalities. Instead of animal feeders, human fibroblasts can be used as feeder cells of human ES cells. However, one still has to be concerned about the existence of unidentified pathogens, such as viruses and prions in these non-autologous feeders. METHODOLOGY/PRINCIPAL FINDINGS: This report demonstrates that human induced Pluripotent Stem (iPS cells can be established and maintained on isogenic parental feeder cells. We tested four independent human skin fibroblasts for the potential to maintain self-renewal of iPS cells. All the fibroblasts tested, as well as their conditioned medium, were capable of maintaining the undifferentiated state and normal karyotypes of iPS cells. Furthermore, human iPS cells can be generated on isogenic parental fibroblasts as feeders. These iPS cells carried on proliferation over 19 passages with undifferentiated morphologies. They expressed undifferentiated pluripotent cell markers, and could differentiate into all three germ layers via embryoid body and teratoma formation. CONCLUSIONS/SIGNIFICANCE: These results suggest that autologous fibroblasts can be not only a source for iPS cells but also be feeder layers. Our results provide a possibility to solve the dilemma by using isogenic fibroblasts as feeder layers of iPS cells. This is an important step toward the establishment of clinical grade iPS cells.

  18. Development of arctic wind technology

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, H.; Marjaniemi, M.; Antikainen, P. [VTT Energy, Espoo (Finland)

    1998-10-01

    The climatic conditions of Lapland set special technical requirements for wind power production. The most difficult problem regarding wind power production in arctic regions is the build-up of hard and rime ice on structures of the machine

  19. SCICEX: Submarine Arctic Science Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  20. Interaction webs in arctic ecosystems

    DEFF Research Database (Denmark)

    Schmidt, Niels M.; Hardwick, Bess; Gilg, Olivier;

    2017-01-01

    How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they ...... that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems....

  1. Influences of Ice Crystal Number Concentrations and Habits on Arctic Mixed-Phase Cloud Dynamics

    Science.gov (United States)

    Komurcu, Muge

    2016-09-01

    Mixed-phase clouds are frequently present in the Arctic atmosphere, and strongly affect the surface energy budget. In this study, the influences of ice crystal number concentrations and crystal growth habits on the Arctic mixed-phase cloud microphysics and dynamics are investigated for internally and externally driven cloud systems using an eddy-resolving model. Separate simulations are performed with increasing ice concentrations and different ice crystal habits. It is found that the habit influence on cloud microphysics and dynamics is as pronounced as increasing the ice crystal concentrations for internally driven clouds and more dominant for externally driven clouds. Habit influence can lead to a 10 % reduction in surface incident longwave radiation flux. Sensitivity tests are performed to identify the interactions between processes affecting cloud dynamics that allow for persistent clouds (i.e., the radiative cooling at cloud top, ice precipitation stabilization at cloud-base). When cloud-base stabilization influences of ice precipitation are weak, cloud dynamics is more sensitive to radiative cooling. Additional sensitivity simulations are done with increasing surface latent and sensible heat fluxes to identify the influences of external forcing on cloud dynamics. It is found that the magnitude of cloud circulations for an externally driven cloud system with strong precipitation and weak surface fluxes is similar to a weakly precipitating, optically thick, internally driven cloud. For cloud systems with intense ice precipitation obtained through either increasing ice crystal concentrations or assuming ice crystal shapes that grow rapidly and fall fast, the cloud layer may collapse despite the moistening effect of surface fluxes.

  2. Arctic species resilience

    DEFF Research Database (Denmark)

    Mortensen, Lars O.; Forchhammer, Mads C.; Jeppesen, Erik

    and precipitation. Concurrently, phenological change has been recorded in a wide range of plants and animals, with climate change seemingly being the primary driver of these changes. A major concern is whether species and biological systems embrace the plasticity in their phenological responses needed for tracking......The peak of biological activities in Arctic ecosystems is characterized by a relative short and intense period between the start of snowmelt until the onset of frost. Recent climate changes have induced larger seasonal variation in both timing of snowmelt as well as changes mean temperatures...... the predicted increase in climate variability. Whereas species may show relatively high phenological resilience to climate change per se, the resilience of systems may be more constrained by the inherent dependence through consumer-resource interactions across trophic levels. During the last 15 years...

  3. 77 FR 31677 - Request for Public Comment on Interagency Arctic Research Policy Committee (IARPC) Arctic...

    Science.gov (United States)

    2012-05-29

    ... TECHNOLOGY POLICY Request for Public Comment on Interagency Arctic Research Policy Committee (IARPC) Arctic... and Policy Act of 1984 (ARPA), Public Law 98-373, established the Interagency Arctic Research Policy Committee (IARPC) to develop national Arctic research policy five-year Federal research plans to...

  4. The Arctic policy of China and Japan

    DEFF Research Database (Denmark)

    Tonami, Aki

    2014-01-01

    At the May 2013 Arctic Council Ministerial Meeting, five Asian states, namely China, Japan, India, Singapore and South Korea, were accepted to become new Permanent Observers at the Arctic Council. Nonetheless, little attention has been paid to the Asian states and their interest in the Arctic. Most...... discussions have focused on China and the assessment of China’s interest in the Arctic is divided. This paper attempts to fill this gap by presenting and comparing the various components of the Arctic policies of China and Japan. Referring to Putnam’s model of the “two-level game” and Young’s categorization...... of Arctic stakeholders’ interests, data from policy documents and interviews with relevant stakeholders were analysed. This analysis shows the Chinese and Japanese governments are in the gradual process of consolidating their Arctic policies, but both China and Japan see the Arctic less as a strategically...

  5. Time varying arctic climate change amplification

    Energy Technology Data Exchange (ETDEWEB)

    Chylek, Petr [Los Alamos National Laboratory; Dubey, Manvendra K [Los Alamos National Laboratory; Lesins, Glen [DALLHOUSIE U; Wang, Muyin [NOAA/JISAO

    2009-01-01

    During the past 130 years the global mean surface air temperature has risen by about 0.75 K. Due to feedbacks -- including the snow/ice albedo feedback -- the warming in the Arctic is expected to proceed at a faster rate than the global average. Climate model simulations suggest that this Arctic amplification produces warming that is two to three times larger than the global mean. Understanding the Arctic amplification is essential for projections of future Arctic climate including sea ice extent and melting of the Greenland ice sheet. We use the temperature records from the Arctic stations to show that (a) the Arctic amplification is larger at latitudes above 700 N compared to those within 64-70oN belt, and that, surprisingly; (b) the ratio of the Arctic to global rate of temperature change is not constant but varies on the decadal timescale. This time dependence will affect future projections of climate changes in the Arctic.

  6. The Arctic policy of China and Japan

    DEFF Research Database (Denmark)

    Tonami, Aki

    2014-01-01

    At the May 2013 Arctic Council Ministerial Meeting, five Asian states, namely China, Japan, India, Singapore and South Korea, were accepted to become new Permanent Observers at the Arctic Council. Nonetheless, little attention has been paid to the Asian states and their interest in the Arctic. Most...... discussions have focused on China and the assessment of China’s interest in the Arctic is divided. This paper attempts to fill this gap by presenting and comparing the various components of the Arctic policies of China and Japan. Referring to Putnam’s model of the “two-level game” and Young’s categorization...... of Arctic stakeholders’ interests, data from policy documents and interviews with relevant stakeholders were analysed. This analysis shows the Chinese and Japanese governments are in the gradual process of consolidating their Arctic policies, but both China and Japan see the Arctic less as a strategically...

  7. Generation of Human Induced Pluripotent Stem Cells from Peripheral Blood Mononuclear Cells Using Sendai Virus.

    Science.gov (United States)

    Soares, Filipa A C; Pedersen, Roger A; Vallier, Ludovic

    2016-01-01

    This protocol describes the efficient isolation of peripheral blood mononuclear cells from circulating blood via density gradient centrifugation and subsequent generation of integration-free human induced pluripotent stem cells. Peripheral blood mononuclear cells are cultured for 9 days to allow expansion of the erythroblast population. The erythroblasts are then used to derive human induced pluripotent stem cells using Sendai viral vectors, each expressing one of the four reprogramming factors Oct4, Sox2, Klf4, and c-Myc.

  8. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    Science.gov (United States)

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-09-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents-Kara seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice reduction warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be free of ice. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents-Kara seas and Laptev, East Siberian, Chukchi, and Beaufort seas.

  9. History of sea ice in the Arctic

    DEFF Research Database (Denmark)

    Polyak, Leonid; Alley, Richard B.; Andrews, John T.

    2010-01-01

    Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past. This inf...

  10. In Brief: Arctic Report Card

    Science.gov (United States)

    Showstack, Randy

    2009-11-01

    The 2009 annual update of the Arctic Report Card, issued on 22 October, indicates that “warming of the Arctic continues to be widespread, and in some cases dramatic. Linkages between air, land, sea, and biology are evident.” The report, a collaborative effort of 71 national and international scientists initiated in 2006 by the Climate Program Office of the U.S. National Oceanic and Atmospheric Administration (NOAA), highlights several concerns, including a change in large-scale wind patterns affected by the loss of summer sea ice; the replacement of multiyear sea ice by first-year sea ice; warmer and fresher water in the upper ocean linked to new ice-free areas; and the effects of the loss of sea ice on Arctic plant, animal, and fish species. “Climate change is happening faster in the Arctic than any other place on Earth-and with wide-ranging consequences,” said NOAA administrator Jane Lubchenco. “This year“s Arctic Report Card underscores the urgency of reducing greenhouse gas pollution and adapting to climate changes already under way.”

  11. Arctic hydrology and meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D.L.

    1988-01-01

    The behavior of arctic ecosystems is directly related to the ongoing physical processes of heat and mass transfer. Furthermore, this system undergoes very large fluctuations in the surface energy balance. The buffering effect of both snow and the surface organic soils can be seen by looking at the surface and 40 cm soil temperatures. The active layer, that surface zone above the permafrost table, is either continually freezing or thawing. A large percentage of energy into and out of a watershed must pass through this thin veneer that we call the active layer. Likewise, most water entering and leaving the watershed does so through the active layer. To date, we have been very successful at monitoring the hydrology of Imnavait Creek with special emphasis on the active layer processes. The major contribution of this study is that year-round hydrologic data are being collected. An original objective of our study was to define how the thermal and moisture regimes within the active layer change during an annual cycle under natural conditions, and then to define how the regime will be impacted by some imposed terrain alteration. Our major analysis of the hydrologic data sets for Imnavait Creek have been water balance evaluations for plots during snowmelt, water balance for the watershed during both rainfall and snowmelt, and the application of a hydrologic model to predict the Imnavait Creek runoff events generated by both snowmelt and rainfall.

  12. Uncertainties in Arctic Precipitation

    Science.gov (United States)

    Majhi, I.; Alexeev, V. A.; Cherry, J. E.; Cohen, J. L.; Groisman, P. Y.

    2012-12-01

    Arctic precipitation is riddled with measurement biases; to address the problem is imperative. Our study focuses on comparison of various datasets and analyzing their biases for the region of Siberia and caution that is needed when using them. Five sources of data were used ranging from NOAA's product (RAW, Bogdanova's correction), Yang's correction technique and two reanalysis products (ERA-Interim and NCEP). The reanalysis dataset performed better for some months in comparison to Yang's product, which tends to overestimate precipitation, and the raw dataset, which tends to underestimate. The sources of bias vary from topography, to wind, to missing data .The final three products chosen show higher biases during the winter and spring season. Emphasis on equations which incorporate blizzards, blowing snow and higher wind speed is necessary for regions which are influenced by any or all of these factors; Bogdanova's correction technique is the most robust of all the datasets analyzed and gives the most reasonable results. One of our future goals is to analyze the impact of precipitation uncertainties on water budget analysis for the Siberian Rivers.

  13. Arctic hydrology and meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D.L.

    1989-01-01

    To date, five years of hydrologic and meteorologic data have been collected at Imnavait Creek near Toolik Lake, Alaska. This is the most complete set of field data of this type collected in the Arctic of North America. These data have been used in process-oriented research to increase our understanding of atmosphere/hydrosphere/biosphere/lithosphere interactions. Basically, we are monitoring heat and mass transfer between various spheres to quantify rates. These could be rates of mass movement such as hillslope flow or rates of heat transfer for active layer thawing or combined heat and mass processes such as evapotranspiration. We have utilized a conceptual model to predict hydrologic processes. To test the success of this model, we are comparing our predicted rates of runoff and snowmelt to measured valves. We have also used a surface energy model to simulate active layer temperatures. The final step in this modeling effort to date was to predict what impact climatic warming would have on active layer thicknesses and how this will influence the hydrology of our research watershed by examining several streambeds.

  14. The Arctic tourism in Russia

    Directory of Open Access Journals (Sweden)

    Yury F. Lukin

    2016-12-01

    Full Text Available In the new book "Arctic tourism in Russia" the basic concepts, resource potential, attractiveness (from Lat. Attrahere: to attract, opportunities and threats of environmental, cruise, international, and other types of tourism in the Arctic are system-based analyzed, for the first time in the literature. The sphere of tourism has becoming an integral sector of the economy, having a multiplicative effect for the development of infrastructure, social services, employment. Reference materials about the tourism products in the Russian Arctic and Far North regions are published, including the Arkhangelsk and Murmansk regions; Republic of Karelia, Komi, Sakha (Yakutia; Nenets, the Yamalo-Nenets, Khanty-Mansiysk, the Chukotka Autonomous Districts; Taimyr Dolgan-Nenets Municipal District, Turukhansk district, the city of Norilsk of the Krasnoyarsk region; Magadan region, Kamchatka region.

  15. Circum-Arctic Map Compilation

    Science.gov (United States)

    Saltus, Richard W.; Gaina, Carmen

    2007-05-01

    Second Workshop of the Circum-Arctic Geophysical Maps Project, Trondheim, Norway, 12-13 February 2007 The eyes of the world are increasingly focused on the polar regions. Exploration and assessment of energy and mineral resources for the growing world economy are moving to high-latitude frontier areas. The effects of climatic changes are particularly pronounced at these ends of the Earth and have already attracted worldwide attention and concern. Many recent articles related to the International Polar Year underscore the importance of even basic mapping of the Arctic and Antarctic.

  16. Interaction webs in arctic ecosystems: Determinants of arctic change?

    DEFF Research Database (Denmark)

    Schmidt, Niels Martin; Hardwick, Bess; Gilg, Olivier

    2017-01-01

    How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they ...

  17. Arctic Glass: Innovative Consumer Technology in Support of Arctic Research

    Science.gov (United States)

    Ruthkoski, T.

    2015-12-01

    The advancement of cyberinfrastructure on the North Slope of Alaska is drastically limited by location-specific conditions, including: unique geophysical features, remoteness of location, and harsh climate. The associated cost of maintaining this unique cyberinfrastructure also becomes a limiting factor. As a result, field experiments conducted in this region have historically been at a technological disadvantage. The Arctic Glass project explored a variety of scenarios where innovative consumer-grade technology was leveraged as a lightweight, rapidly deployable, sustainable, alternatives to traditional large-scale Arctic cyberinfrastructure installations. Google Glass, cloud computing services, Internet of Things (IoT) microcontrollers, miniature LIDAR, co2 sensors designed for HVAC systems, and portable network kits are several of the components field-tested at the Toolik Field Station as part of this project. Region-specific software was also developed, including a multi featured, voice controlled Google Glass application named "Arctic Glass". Additionally, real-time sensor monitoring and remote control capability was evaluated through the deployment of a small cluster of microcontroller devices. Network robustness was analyzed as the devices delivered streams of abiotic data to a web-based dashboard monitoring service in near real time. The same data was also uploaded synchronously by the devices to Amazon Web Services. A detailed overview of solutions deployed during the 2015 field season, results from experiments utilizing consumer sensors, and potential roles consumer technology could play in support of Arctic science will be discussed.

  18. Changing Arctic ecosystems: ecology of loons in a changing Arctic

    Science.gov (United States)

    Uher-Koch, Brian; Schmutz, Joel; Whalen, Mary; Pearce, John M.

    2014-01-01

    The U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative informs key resource management decisions for Arctic Alaska by providing scientific information on current and future ecosystem response to a changing climate. From 2010 to 2014, a key study area for the USGS CAE initiative has been the Arctic Coastal Plain of northern Alaska. This region has experienced rapid warming during the past 30 years, leading to the thawing of permafrost and changes to lake and river systems. These changes, and projections of continued change, have raised questions about effects on wildlife populations that rely on northern lake ecosystems, such as loons. Loons rely on freshwater lakes for nesting habitat and the fish and invertebrates inhabiting the lakes for food. Loons live within the National Petroleum Reserve-Alaska (NPR-A) on Alaska’s northern coast, where oil and gas development is expected to increase. Research by the USGS examines how breeding loons use the Arctic lake ecosystem and the capacity of loons to adapt to future landscape change.

  19. Arctic resources : a mechatronics opportunity

    Energy Technology Data Exchange (ETDEWEB)

    McKean, M.; Baiden, G. [Penguin Automated Systems Inc., Naughton, ON (Canada)

    2008-07-01

    This paper discussed the telerobotic mechatronics opportunities that exist to access mineral resources in the Arctic. The Mining Automation Project (MAP) determined that telerobotics could contribute to productivity gains while providing increased worker safety. The socio-economic benefits of advanced mechatronics for Arctic resource development are particularly attractive due to reduced infrastructure needs; operating costs; and environmental impacts. A preliminary analysis of mining transportation options by the authors revealed that there is a case for in-situ resource utilization (ISRU) for oil and gas processing to address resource development. The ISRU options build on concepts developed to support space exploration and were proposed to reduce or modify transportation loads to allow more sustainable and efficient Arctic resource development. Many benefits in terms of efficiency could be achieved by combining demonstrated mechatronics with ISRU because of the constrained transportation infrastructure in the Arctic. In the context of harsh environment operations, mechatronics may provide an opportunity for undersea resource facilities. 15 refs., 6 figs.

  20. Mining in the European Arctic

    NARCIS (Netherlands)

    van Dam, Karin; Scheepstra, Adriana; Gille, Johan; Stepien, Adam; Koivurova, Timo; Stepien, Adam; Koivurova, Timo; Kankaanpää, Paula

    2016-01-01

    The European Arctic has been recently experiencing an upsurge in mining activities. This is reflected in an on-going interest from the industry, regulators and the public. However, current and future prospects are highly sensitive to mineral price fluctuations. The EU is a major consumer and importe

  1. Changing Arctic Ocean freshwater pathways.

    Science.gov (United States)

    Morison, James; Kwok, Ron; Peralta-Ferriz, Cecilia; Alkire, Matt; Rigor, Ignatius; Andersen, Roger; Steele, Mike

    2012-01-04

    Freshening in the Canada basin of the Arctic Ocean began in the 1990s and continued to at least the end of 2008. By then, the Arctic Ocean might have gained four times as much fresh water as comprised the Great Salinity Anomaly of the 1970s, raising the spectre of slowing global ocean circulation. Freshening has been attributed to increased sea ice melting and contributions from runoff, but a leading explanation has been a strengthening of the Beaufort High--a characteristic peak in sea level atmospheric pressure--which tends to accelerate an anticyclonic (clockwise) wind pattern causing convergence of fresh surface water. Limited observations have made this explanation difficult to verify, and observations of increasing freshwater content under a weakened Beaufort High suggest that other factors must be affecting freshwater content. Here we use observations to show that during a time of record reductions in ice extent from 2005 to 2008, the dominant freshwater content changes were an increase in the Canada basin balanced by a decrease in the Eurasian basin. Observations are drawn from satellite data (sea surface height and ocean-bottom pressure) and in situ data. The freshwater changes were due to a cyclonic (anticlockwise) shift in the ocean pathway of Eurasian runoff forced by strengthening of the west-to-east Northern Hemisphere atmospheric circulation characterized by an increased Arctic Oscillation index. Our results confirm that runoff is an important influence on the Arctic Ocean and establish that the spatial and temporal manifestations of the runoff pathways are modulated by the Arctic Oscillation, rather than the strength of the wind-driven Beaufort Gyre circulation.

  2. The Submarine -- The Key to Winning an Arctic Conflict

    Science.gov (United States)

    2013-05-15

    Cold Horizons: Arctic Maritime Security Challenges.” 17 Franklyn Griffiths, Rob Huebert, and P. Whitney Lackenbauer, Canada and the Changing Arctic... Franklyn , Rob Huebert, and P. Whitney Lackenbauer. Canada and the Changing Arctic: Sovereignty, Security, and Stewardship. Waterloo, Ontario

  3. Geologic Provinces of the Circum-Arctic, 2008 (north of the Arctic Circle)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile includes arcs and polygons that describe U.S. Geological Survey defined 33 geologic provinces of the Circum-Arctic (north of the Arctic Circle). Each...

  4. Domesticating the Arctic: A Discourse Analysis of Canada's Arctic Foreign Policy

    OpenAIRE

    Aaser, Agnes Viktoria

    2014-01-01

    This thesis investigates how the concept the Arctic is utilized in a Canadian Arctic foreign policy context today. The thesis main argument is that the Canadian government discursively represents the Arctic as a domestic space by drawing on cultural references, historical analogies, geopolitical identity and representation of danger and external threats. This argument is based on a qualitative study of key Arctic policy documents produced by the Harper government since 2009. The study is...

  5. The Evolving Arctic: Current State of U.S. Arctic Policy

    Science.gov (United States)

    2013-09-01

    obvious that improvements need to be made to guard U.S. interests While the U.S. procrastinates in taking its rightful place in the Arctic, Russia...foreign policy priority.87 1. Exercising Arctic Sovereignty As an Arctic nation, Canada firmly understands the importance of ensuring and...domain awareness in the region.88 In May 2010, Canadian and Danish military leaders signed a memorandum of understanding on Arctic defense, security

  6. Changes in the Arctic: Background and Issues for Congress

    Science.gov (United States)

    2010-03-30

    established the U.S. Arctic Research Commission (USARC) to promote Arctic research and recommend Arctic research policy ; • designated the National Science...Foundation (NSF) as the lead federal agency for implementing Arctic research policy ; • established the Interagency Arctic Research Policy Committee...IARPC) to develop a national Arctic research policy and a five-year plan to implement that policy, and designated the NSF representative on the IARPC

  7. Strategic metal deposits of the Arctic Zone

    Science.gov (United States)

    Bortnikov, N. S.; Lobanov, K. V.; Volkov, A. V.; Galyamov, A. L.; Vikent'ev, I. V.; Tarasov, N. N.; Distler, V. V.; Lalomov, A. V.; Aristov, V. V.; Murashov, K. Yu.; Chizhova, I. A.; Chefranov, R. M.

    2015-11-01

    Mineral commodities rank high in the economies of Arctic countries, and the status of mineral resources and the dynamics of their development are of great importance. The growing tendency to develop strategic metal resources in the Circumarctic Zone is outlined in a global perspective. The Russian Arctic Zone is the leading purveyor of these metals to domestic and foreign markets. The comparative analysis of tendencies in development of strategic metal resources of the Arctic Zone in Russia and other countries is crucial for the elaboration of trends of geological exploration and research engineering. This paper provides insight into the development of Arctic strategic metal resources in global perspective. It is shown that the mineral resource potential of the Arctic circumpolar metallogenic belt is primarily controlled by large and unique deposits of nonferrous, noble, and rare metals. The prospective types of economic strategic metal deposits in the Russian Arctic Zone are shown.

  8. Arctic tipping points: governance in turbulent times.

    Science.gov (United States)

    Young, Oran R

    2012-02-01

    Interacting forces of climate change and globalization are transforming the Arctic. Triggered by a non-linear shift in sea ice, this transformation has unleashed mounting interest in opportunities to exploit the region's natural resources as well as growing concern about environmental, economic, and political issues associated with such efforts. This article addresses the implications of this transformation for governance, identifies limitations of existing arrangements, and explores changes needed to meet new demands. It advocates the development of an Arctic regime complex featuring flexibility across issues and adaptability over time along with an enhanced role for the Arctic Council both in conducting policy-relevant assessments and in promoting synergy in interactions among the elements of the emerging Arctic regime complex. The emphasis throughout is on maximizing the fit between the socioecological features of the Arctic and the character of the governance arrangements needed to steer the Arctic toward a sustainable future.

  9. Arctic whaling : proceedings of the International Symposium Arctic Whaling February 1983

    NARCIS (Netherlands)

    Jacob, H.K. s'; Snoeijing, K

    1984-01-01

    Contents: D.M. Hopkins and Louie Marincovich Jr. Whale Biogeography and the history of the Arctic Basin P.M. Kellt, J.H.W. Karas and L.D. Williams Arctic Climate: Past, Present and Future Torgny E. Vinje On the present state and the future fate of the Arctic sea ice cover P.J.H. van Bree On the biol

  10. The motives and interests of non-Arctic states on Arctic development

    OpenAIRE

    Sergey N. Grinyaev

    2016-01-01

    The article summarizes the work of the Center for Strategic Assessments and Forecasts on the study of strategy and policy of the Arctic Council observer countries. It is proposed in the number of the Arctic Council observer organizations include the Russian Geographical Society — internationally recognized and oldest scientific community, which has made a significant contribution to the development of the Arctic.

  11. Benefiting Qi and moistening lung for arresting cough combined with Western medicine in the treatment of 56 children with bronchial asthma in remission stage%益气润肺止咳法结合西药治疗儿童支气管哮喘缓解期56例疗效观察

    Institute of Scientific and Technical Information of China (English)

    陈定锋

    2012-01-01

    Objective To observe the clinical effect ofarresting cough therapy by benefiting Qi and moistening lung combined with Western medicine in the treatment of bronchial asthma in children. Methods 56 children of bronchial asthma were randomly divided into two groups. The study group (n=30) received arresting cough therapy by benefiting Qi and moistening lung combined with routine Western medicine therapy. The control group (n=26) were treated with conventional treatment of Western medicine, for two weeks. Results The effective rate was 95% in the study group and 80% in the control group, with statistically significant difference between the two groups (P<0.05). Conclusion Benefiting Qi and moistening lung for arresting cough combined with Western medicine is quite effective for treating bronchial asthma.%目的 观察益气润肺止咳法结合西药治疗支气管哮喘的临床疗效.方法 将56例支气管哮喘患者随机分为两组.治疗组30例,予益润肺止咳法结合西药常规治疗;对照组26例,予西药常规治疗,疗程为两周.结果 治疗组有效率为95%,对照组为80%,两组总有效率比较,差异有统计学意义(P<0.05).结论 益气润肺止咳法结合西药治疗支气管哮喘疗效确切.

  12. Multiscale Models of Melting Arctic Sea Ice

    Science.gov (United States)

    2014-09-30

    1 Multiscale Models of Melting Arctic Sea Ice Kenneth M. Golden University of Utah, Department of Mathematics phone: (801) 581-6851...feedback has played a major role in the recent declines of the summer Arctic sea ice pack. However, understanding the evolution of melt ponds and sea...Models of Melting Arctic Sea Ice 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER

  13. Arctic Security in a Warming World

    Science.gov (United States)

    2010-03-01

    is much shallower and littered with small islands. The two northern variants are the primary avenues for growth in international shipping. Figure...in the Arctic is the explosion of opportunities for tourism . This influx of large numbers of people has the potential to be the greatest threat to...lie with expanded Arctic tourism . A distressed tourist vessel in the hostile conditions and remote regions of the Arctic could quickly develop into a

  14. Shallow water benthic foraminifera as proxy for natural versus human-induced environmental change

    NARCIS (Netherlands)

    Nooijer, L.J. de

    2007-01-01

    Ecosystem composition and functioning is not only subjected to human-induced alterations, ecosystems also subjected to natural (e.g. climate-induced) variability. To quantify human impacts on ecosystems, these natural fluctuations must be accounted for. Since long-term biological monitoring programs

  15. Shallow water benthic foraminifera as proxy for natural versus human-induced environmental change

    NARCIS (Netherlands)

    Nooijer, L.J. de

    2007-01-01

    Ecosystem composition and functioning is not only subjected to human-induced alterations, ecosystems also subjected to natural (e.g. climate-induced) variability. To quantify human impacts on ecosystems, these natural fluctuations must be accounted for. Since long-term biological monitoring programs

  16. Choices for Induction of Pluripotency: Recent Developments in Human Induced Pluripotent Stem Cell Reprogramming Strategies

    NARCIS (Netherlands)

    Brouwer, M.; Zhou, Huiqing; Nadif Kasri, N.

    2016-01-01

    The ability to generate human induced pluripotent stem cells (iPSCs) from somatic cells provides tremendous promises for regenerative medicine and its use has widely increased over recent years. However, reprogramming efficiencies remain low and chromosomal instability and tumorigenic potential are

  17. Rossby Waves in the Arctic Ocean

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Schmith, Torben

    The Arctic Ocean has a characteristic stable stratification with fresh and cold water occupying the upper few hundred meters and the warm and more saline Atlantic waters underneath. These water masses are separated by the cold halocline. The stability of the cold halocline regulates the upward...... directed turbulent heat flux from the Atlantic water to the Arctic water. This heat flux is a part of the arctic energy budget and is important for large scale sea ice formation and melting. Due to the strong vertical stratification combined with its almost circular boundary, the Arctic Ocean supports...

  18. Arctic tides from GPS on sea ice

    DEFF Research Database (Denmark)

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing...... of Global Positioning System (GPS) buoys placed on sea-ice at five different sites north of Greenland for the study of sea level height and tidal analysis to improve tidal models in the Central Arctic. The GPS measurements are compared with the Arctic tidal model AOTIM-5, which assimilates tide...

  19. Rossby Waves in the Arctic Ocean

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Schmith, Torben

    The Arctic Ocean has a characteristic stable stratification with fresh and cold water occupying the upper few hundred meters and the warm and more saline Atlantic waters underneath. These water masses are separated by the cold halocline. The stability of the cold halocline regulates the upward...... directed turbulent heat flux from the Atlantic water to the Arctic water. This heat flux is a part of the arctic energy budget and is important for large scale sea ice formation and melting. Due to the strong vertical stratification combined with its almost circular boundary, the Arctic Ocean supports...... of the thermohaline circulation....

  20. Arctic decadal variability in a warming world

    Science.gov (United States)

    van der Linden, Eveline C.; Bintanja, Richard; Hazeleger, Wilco

    2017-06-01

    Natural decadal variability of surface air temperature might obscure Arctic temperature trends induced by anthropogenic forcing. It is therefore imperative to know how Arctic decadal variability (ADV) will change as the climate warms. In this study, we evaluate ADV characteristics in three equilibrium climates with present-day, double, and quadrupled atmospheric CO2 forcing. The dominant region of variability, which is located over the Barents and Greenland Sea at present, shifts to the central Arctic and Siberian regions as the climate warms. The maximum variability in sea ice cover and surface air temperature occurs in the CO2 doubling climate when sea ice becomes more vulnerable to melt over vast stretches of the Arctic. Furthermore, the links between dominant atmospheric circulation modes and Arctic surface climate characteristics vary strongly with climate change. For instance, a positive Arctic Oscillation index is associated with a colder Arctic in warmer climates, instead of a warmer Arctic at present. Such changing relationships are partly related to the retreat of sea ice because altered wind patterns influence the sea ice distribution and hence the associated local surface fluxes. The atmospheric pressure distributions governing ADV and the associated large-scale dynamics also change with climate warming. The changing character of the ADV shows that it is vital to consider (changes in) ADV when addressing Arctic warming in climate model projections.

  1. Plate tectonic history of the Arctic

    Science.gov (United States)

    Burke, K.

    1984-01-01

    Tectonic development of the Arctic Ocean is outlined, and geological maps are provided for the Arctic during the mid-Cenozoic, later Cretaceous, late Jurassic, early Cretaceous, early Jurassic and late Devonian. It is concluded that Arctic basin history is moulded by the events of the following intervals: (1) continental collision and immediately subsequent rifting and ocean formation in the Devonian, and continental rifting ocean formation, rapid rotation of microcontinents, and another episode of collision in the latest Jurassic and Cretaceous. It is noted that Cenozoic Arctic basin formation is a smaller scale event superimposed on the late Mesozoic ocean basin.

  2. China's Developing Arctic Policies: Myths and Misconceptions

    Directory of Open Access Journals (Sweden)

    Marc Lanteigne

    2015-12-01

    Full Text Available The Arctic and Far North regions of the world have grown in importance for China's international interests in recent years, and in 2013 China became an observer state in the Arctic Council. Beijing has sought to develop an Arctic policy based on scientific research and partnerships, including in the areas of environmental studies and climate change issues, as well as development and economic issues. As the Arctic gains more international attention due to the effects of ice melting and the possibility of the region becoming a new source of resources, concerns have been raised about a scramble for riches and economic advantages. China, as a rising political and economic power, has been subject to much scrutiny, especially from the West, about its emerging agenda in the Arctic region. Although China is not an Arctic state, the concerns are based on predictions that Beijing is seeking to play a stronger and perhaps even dominant role in the Arctic, and this has led to many misconceptions about China's Arctic policy. The result has been a "clash of identities" between Chinese and Western perceptions, and in order to understand why these diverging views have appeared, it is necessary to first examine the origins of "myths" about China's regional Arctic policies, and then examine their roles, using constructivist theory, before suggesting ways for both China and the international community to address this divergence.

  3. Plate tectonic history of the Arctic

    Science.gov (United States)

    Burke, K.

    1984-01-01

    Tectonic development of the Arctic Ocean is outlined, and geological maps are provided for the Arctic during the mid-Cenozoic, later Cretaceous, late Jurassic, early Cretaceous, early Jurassic and late Devonian. It is concluded that Arctic basin history is moulded by the events of the following intervals: (1) continental collision and immediately subsequent rifting and ocean formation in the Devonian, and continental rifting ocean formation, rapid rotation of microcontinents, and another episode of collision in the latest Jurassic and Cretaceous. It is noted that Cenozoic Arctic basin formation is a smaller scale event superimposed on the late Mesozoic ocean basin.

  4. Scenarios Creation and Use in the Arctic Council's Arctic Marine Shipping Assessment

    Science.gov (United States)

    Brigham, L. W.

    2016-12-01

    The Arctic Council's Arctic Marine Shipping Assessment (AMSA), conducted 2004-2009, used a scenarios-based approach to reveal the complexity of future Arctic marine navigation and to develop a set of plausible futures. The initial task was to use experts and stakeholders in brainstorming sessions to identify the key drivers and uncertainties for Arctic marine navigation. AMSA scenario participants identified 120 driving forces or factors that may influence future levels of marine activity. This effort illustrated the broad, global connections that can impact future use of the Arctic Ocean. Two primary factors were selected to anchor, as axes of uncertainty, the scenarios matrix: resources and trade (the level of demand for Arctic natural resources and trade); and, governance (the degree of relative stability of rules and standards for marine use both within the Arctic and internationally). Four scenarios were created by crossing the two primary drivers: a Polar Lows scenario (low demand and unstable governance); an Arctic Race scenario (high demand and unstable governance); a Polar Preserve scenario (low demand and stable governance); and, an Arctic Saga scenario (high demand and stable governance). The AMSA scenarios effort proved to be an effective and powerful way to communicate to the Arctic Council diplomats, Arctic indigenous peoples, maritime stakeholders and many other actors in the global community the complexities influencing the future of Arctic shipping and marine operations. The scenarios approach facilitated unconstrained thinking and identified the many plausible linkages of the Arctic to the global economic system. The AMSA scenarios work was influential in the Arctic ministers' approval of the framework set of AMSA recommendations that are being implemented today to enhance Arctic marine safety and environmental protection.

  5. Extrapolating future Arctic ozone losses

    Directory of Open Access Journals (Sweden)

    B. M. Knudsen

    2004-06-01

    Full Text Available Future increases in the concentration of greenhouse gases and water vapour are likely to cool the stratosphere further and to increase the amount of polar stratospheric clouds (PSCs. Future Arctic PSC areas have been extrapolated using the highly significant trends in the temperature record from 1958–2001. Using a tight correlation between PSC area and the total vortex ozone depletion and taking the decreasing amounts of ozone depleting substances into account we make empirical estimates of future ozone. The result is that Arctic ozone losses increase until 2010–2020 and only decrease slightly up to 2030. This approach is an alternative method of prediction to that based on the complex coupled chemistry-climate models (CCMs.

  6. Stories from the Arctic field

    Science.gov (United States)

    Cain, Michelle

    2016-04-01

    I will discuss my experience co-ordinating a range of communication activities for a multi-university research programme called Methane in the Arctic: Measurements and Modelling. The project included ground- and aircraft-based fieldwork in the European Arctic, as well as computer modelling. Our communication activities included: our own field blog (www.arcticmethane.wordpress.com), which was syndicated to the Scientific American Expeditions blog; writing articles for other blogs with a wider audience than our own; use of twitter; and podcasting our field work. The grand finale to our communications work was a live event at a science festival, in which we took the audience along with us on a recreated research flight, complete with a life-size mock up of a section of our research aircraft. I will discuss my experiences of these forms of communication, and give an evaluation of their successes and failures.

  7. Aerosols indirectly warm the Arctic

    Directory of Open Access Journals (Sweden)

    T. Mauritsen

    2010-07-01

    Full Text Available On average, airborne aerosol particles cool the Earth's surface directly by absorbing and scattering sunlight and indirectly by influencing cloud reflectivity, life time, thickness or extent. Here we show that over the central Arctic Ocean, where there is frequently a lack of aerosol particles upon which clouds may form, a small increase in aerosol loading may enhance cloudiness thereby likely causing a climatologically significant warming at the ice-covered Arctic surface. Under these low concentration conditions cloud droplets grow to drizzle sizes and fall, even in the absence of collisions and coalescence, thereby diminishing cloud water. Evidence from a case study suggests that interactions between aerosol, clouds and precipitation could be responsible for attaining the observed low aerosol concentrations.

  8. Arctic bioremediation -- A case study

    Energy Technology Data Exchange (ETDEWEB)

    Smallbeck, D.R.; Ramert, P.C. (Harding Lawson Associates, Novato, CA (United States)); Liddell, B.V.

    1994-05-01

    This paper discusses the use of bioremediation as an effective method to clean up diesel-range hydrocarbon spills in northern latitudes. The results of a laboratory study of microbial degradation of hydrocarbons under simulated arctic conditions showed that bioremediation can be effective in cold climates and led to the implementation of a large-scale field program. The results of 3 years of field testing have led to a significant reduction in diesel-range hydrocarbon concentrations in the contaminated area.

  9. Building Materials in Arctic Climate

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    2005-01-01

    Building in the artic requires special attention on the appropriateness of building materials. The harsh climate makes execution difficult and sets unusual requirements for the pure material properties. In addition, there is a lack of choice of good, natural building materials in the arctic....... This results in high transport costs. The building materials situation in Greenland may potentially be improved by intensifying the reuse of building materials or by promoting the local production of building materials....

  10. Arctic Change Information for a Broad Audience

    Science.gov (United States)

    Soreide, N. N.; Overland, J. E.; Calder, J.

    2002-12-01

    Demonstrable environmental changes have occurred in the Arctic over the past three decades. NOAA's Arctic Theme Page is a rich resource web site focused on high latitude studies and the Arctic, with links to widely distributed data and information focused on the Arctic. Included is a collection of essays on relevant topics by experts in Arctic research. The website has proven useful to a wide audience, including scientists, students, teachers, decision makers and the general public, as indicated through recognition by USA Today, Science magazine, etc. (http://www.arctic.noaa.gov) Working jointly with NSF and the University of Washington's Polar Science Center as part of the Study of Environmental Arctic Change (SEARCH) program, NOAA has developed a website for access to pan-Arctic time series spanning diverse data types including climate indices, atmospheric, oceanic, sea ice, terrestrial, biological and fisheries. Modest analysis functions and more detailed analysis results are provided. (http://www.unaami.noaa.gov/). This paper will describe development of an Artic Change Detection status website to provide a direct and comprehensive view of previous and ongoing change in the Arctic for a broad climate community. For example, composite metrics are developed using principal component analysis based on 86 multivariate pan-Arctic time series for seven data types. Two of these metrics can be interpreted as a regime change/trend component and an interdecadal component. Changes can also be visually observed through tracking of 28 separate biophysical indicators. Results will be presented in the form of a web site with relevant, easily understood, value-added knowledge backed by peer review from Arctic scientists and scientific journals.

  11. Effects of Different Raw Material Proportions and Moistening Levels on pH Value and Enzyme Activity during Koj i-making Process%制曲过程中不同原料配比、润水量对成曲pH 值、酶活的影响研究

    Institute of Scientific and Technical Information of China (English)

    陈振伟

    2014-01-01

    Analyze the effects of different raw material proportions and moistening levels on pH value and enzyme activity during koji-making process,set six groups of different raw material proportions and moistening levels using the same kind of koj i under the same conditions.The result reflects that the effect of infeed-koji water content on finished koji pH value is greater than that of raw material proportion on pH value;while water has greater effect on finished koji enzyme activity than raw material proportion.%通过使用同一种曲,设定六组不同原料配比、润水量,在同一条件下进行制曲,研究了制曲过程中不同原料配比、润水量对成曲 pH 值、酶活的影响。结果表明:入曲水分对成曲 pH 的影响比原料配比对pH 的影响要大;成曲酶活受水分的影响比受原料配比的影响大。

  12. Arctic decadal variability in a warming world

    NARCIS (Netherlands)

    Linden, van der Eveline C.; Bintanja, Richard; Hazeleger, Wilco

    2017-01-01

    Natural decadal variability of surface air temperature might obscure Arctic temperature trends induced by anthropogenic forcing. It is therefore imperative to know how Arctic decadal variability (ADV) will change as the climate warms. In this study, we evaluate ADV characteristics in three

  13. Towards a rain-dominated Arctic

    NARCIS (Netherlands)

    Bintanja, Richard; Andry, Olivier

    2017-01-01

    Climate models project a strong increase in Arctic precipitation over the coming century1, which has been attributed primarily to enhanced surface evaporation associated with sea-ice retreat2. Since the Arctic is still quite cold, especially in winter, it is often (implicitly) assumed that the

  14. Arctic Planning Scenarios: Scenario #1: Defence Scenario

    Science.gov (United States)

    2011-07-01

    Arctic, it appeared ready for compromises. Minister Cannon did not rule out, after his talks in Moscow, that Canada and Russia could submit a joint...process. Russia’s national ambitions in the region have been summarised by Artur Chilingarov, an Arctic explorer and the State Duma’s vice-spokesman

  15. Pacific Northwest Laboratory Alaska (ARCTIC) research program

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, W.C.; Eberhardt, L.E.

    1980-03-01

    The current program continues studies of arctic ecosystems begun in 1959 as part of the Cape Thompson Program. Specific ecosystem aspects include studies of the ecology of arctic and red foxes, small mammel and bird population studies, lichen studies, and radiation ecology studies. (ACR)

  16. Traditional Ecological Knowledge in Arctic EIA's

    DEFF Research Database (Denmark)

    Egede, Parnuna Petrina; Hansen, Anne Merrild

    2017-01-01

    The search for new oil and mineral reserves in the Arctic is increasing. This has called for both local and international concerns and opposition to the activities based on environmental apprehensions. Environmental Impact Assessments (EIA’s) have been implemented in legislations by the Arctic...

  17. Benefit-sharing arrangements in the Arctic

    NARCIS (Netherlands)

    Tysyachnyouk, M.

    2016-01-01

    Can the interests of both the extractive industries and Indigenous communities in the Arctic be balanced through the implementation of benefit-sharing practices in the places of resource extraction? Most transnational corporations
    in the Arctic oil and gas sector have declared their commitment

  18. Linking Arctic amplification and local feedbacks

    Science.gov (United States)

    Balcerak, Ernie

    2011-11-01

    Climate simulations show that as the Earth warms, the Arctic warms more than the average global warming. However, models differ on how much more the Arctic warms, and although scientists have proposed a variety of mechanisms to explain the Arctic warming amplification, there is no consensus on the main reasons for it. To shed light on this issue, Hwang et al. investigated the relationship between Arctic amplification and poleward energy transport and local Arctic feedbacks, such as changes in cloud cover or ice loss, across a group of models. The researchers noted that differences in atmospheric energy transport did not explain the ranges of polar amplification; rather, models with more amplification showed less energy transport into high latitudes. The authors found that decreasing energy transport is due to a coupled relationship between Arctic amplification and energy transport: Arctic amplification reduces the equator-to-pole temperature gradient, which strongly decreases energy transport. They suggest that this coupled relationship should be taken into account in studies of Arctic amplification. (Geophysical Research Letters, doi:10.1029/2011GL048546, 2011)

  19. Arctic freshwater export: Status, mechanisms, and prospects

    NARCIS (Netherlands)

    Haine, T.W.N.; Curry, B.; Gerdes, R.; Hansen, E.; Karcher, M.; Lee, C.; Rudels, B.; Spreen, G.; de Steur, L.; Stewart, K.D.; Woodgate, R.

    2015-01-01

    Large freshwater anomalies clearly exist in the Arctic Ocean. For example, liquid freshwater has accumulated in the Beaufort Gyre in the decade of the 2000s compared to 1980–2000, with an extra ˜ 5000 km3 — about 25% — being stored. The sources of freshwater to the Arctic from precipitation and runo

  20. International Regulation of Central Arctic Ocean Fisheries

    NARCIS (Netherlands)

    Molenaar, E.J.

    2016-01-01

    Due in particular to the impacts of climate change, the adequacy of the international regulation of Central Arctic Ocean fisheries has come under increasing scrutiny in recent years. As shown in this article, however, international regulation of Central Arctic Ocean fisheries is by no means entirely

  1. Benefit-sharing arrangements in the Arctic

    NARCIS (Netherlands)

    Tysyachnyouk, M.

    2016-01-01

    Can the interests of both the extractive industries and Indigenous communities in the Arctic be balanced through the implementation of benefit-sharing practices in the places of resource extraction? Most transnational corporations
    in the Arctic oil and gas sector have declared their commitment t

  2. 78 FR 12033 - Programs and Research Projects Affecting the Arctic

    Science.gov (United States)

    2013-02-21

    ... From the Federal Register Online via the Government Publishing Office ] ARCTIC RESEARCH COMMISSION Programs and Research Projects Affecting the Arctic Notice is hereby given that the U.S. Arctic Research...) Commissioners and staff reports (4) Discussion and presentations concerning Arctic research activities The...

  3. Establishing Shared Knowledge about Globalization in Asia and the Arctic

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Graczyk, Piotr

    2016-01-01

    We discuss the role of knowledge in relations between Arctic communities and Asia (the Arctic Council observer states: China, India, Japan, Singapore, South Korea). We argue that mutual and shared knowledge between Arctic communities and Asia is necessary for local benefits and comprehensively...... sustainable development for Arctic communities under globalization....

  4. Marine Transportation Implications of the Last Arctic Sea Ice Refuge

    Science.gov (United States)

    Brigham, L. W.

    2010-12-01

    Marine access is increasing throughout the Arctic Ocean and the 'Last Arctic Sea Ice Refuge' may have implications for governance and marine use in the region. Arctic marine transportation is increasing due to natural resource developemnt, increasing Arctic marine tourism, expanded Arctic marine research, and a general linkage of the Arctic to the gloabl economy. The Arctic Council recognized these changes with the release of the Arctic Marine Shipping Assessment of 2009. This key study (AMSA)can be viewed as a baseline assessment (using the 2004 AMSA database), a strategic guide for a host of stakeholders and actors, and as a policy document of the Arctic Council. The outcomes of AMSA of direct relevance to the Ice Refuge are within AMSA's 17 recommendations provided under three themes: Enhancing Arctic Marine Safety, Protecting Arctic People and the Environment, and Building the Arctic Marine Infrastructure. Selected recommendations of importance to the Ice Refuge include: a mandatory polar navigation code; identifying areas of heightened ecological and cultural significance; potential designation of special Arctic marine areas; enhancing the tracking and monitoring of Arctic marine traffic; improving circumpolar environmental response capacity; developing an Arctic search and rescue agreement; and, assessing the effects of marine transportation on marine mammals. A review will be made of the AMSA outcomes and how they can influence the governance, marine use, and future protection of this unique Arctic marine environment.

  5. Marine Arctic science capability making big strides

    Science.gov (United States)

    Johnson, Leonard; Brass, Garrett

    The profound influence of the Arctic Ocean on global environment, the rapid variability of Arctic processes, and the unresolved geology of the ocean floor have led to growing scientific interest in this region. Ongoing studies are investigating recent historical processes and modern processes such as changes in ocean circulation and ice cover patterns. Sediments beneath the Arctic Ocean record long- and short-term waxing and waning of the cryosphere in the Northern Hemisphere and its linkages to bottom water renewal and faunal adaptation. Underlying basement rocks reflect the tectonic history of the ocean basin, including its ridges and plateaus, which are unsampled and of unknown composition and origin. The vulnerability of Arctic populations to environmental problems makes the need to understand the region even more compelling (see, for example, Arctic Monitoring and Assessment Programme, 1997; also see Web site http://www.grida.no/amap).

  6. Tipping elements in the Arctic marine ecosystem.

    Science.gov (United States)

    Duarte, Carlos M; Agustí, Susana; Wassmann, Paul; Arrieta, Jesús M; Alcaraz, Miquel; Coello, Alexandra; Marbà, Núria; Hendriks, Iris E; Holding, Johnna; García-Zarandona, Iñigo; Kritzberg, Emma; Vaqué, Dolors

    2012-02-01

    The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem.

  7. CHARACTERISTICS OF HYDROCARBON EXPLOITATION IN ARCTIC CIRCLE

    Directory of Open Access Journals (Sweden)

    Vanja Lež

    2013-12-01

    Full Text Available The existence of large quantities of hydrocarbons is supposed within the Arctic Circle. Assumed quantities are 25% of the total undiscovered hydrocarbon reserves on Earth, mostly natural gas. Over 500 major and minor gas accumulations within the Arctic Circle were discovered so far, but apart from Snøhvit gas field, there is no commercial exploitation of natural gas from these fields. Arctic gas projects are complicated, technically hard to accomplish, and pose a great threat to the return of investment, safety of people and equipment and for the ecosystem. Russia is a country that is closest to the realization of the Arctic gas projects that are based on the giant gas fields. The most extreme weather conditions in the seas around Greenland are the reason why this Arctic region is the least explored and furthest from the realization of any gas project (the paper is published in Croatian .

  8. Advancing NOAA NWS Arctic Program Development

    Science.gov (United States)

    Timofeyeva-Livezey, M. M.; Horsfall, F. M. C.; Meyers, J. C.; Churma, M.; Thoman, R.

    2016-12-01

    Environmental changes in the Arctic require changes in the way the National Oceanic and Atmospheric Administration (NOAA) delivers hydrological and meteorological information to prepare the region's societies and indigenous population for emerging challenges. These challenges include changing weather patterns, changes in the timing and extent of sea ice, accelerated soil erosion due to permafrost decline, increasing coastal vulnerably, and changes in the traditional food supply. The decline in Arctic sea ice is opening new opportunities for exploitation of natural resources, commerce, tourism, and military interest. These societal challenges and economic opportunities call for a NOAA integrated approach for delivery of environmental information including climate, water, and weather data, forecasts, and warnings. Presently the NOAA Arctic Task Force provides leadership in programmatic coordination across NOAA line offices. National Weather Service (NWS) Alaska Region and the National Centers for Environmental Prediction (NCEP) provide the foundational operational hydro-meteorological products and services in the Arctic. Starting in 2016, NOAA's NWS will work toward improving its role in programmatic coordination and development through assembling an NWS Arctic Task Team. The team will foster ties in the Arctic between the 11 NWS national service programs in climate, water, and weather information, as well as between Arctic programs in NWS and other NOAA line offices and external partners. One of the team outcomes is improving decision support tools for the Arctic. The Local Climate Analysis Tool (LCAT) currently has more than 1100 registered users, including NOAA staff and technical partners. The tool has been available online since 2013 (http://nws.weather.gov/lcat/ ). The tool links trusted, recommended NOAA data and analytical capabilities to assess impacts of climate variability and climate change at local levels. A new capability currently being developed will

  9. Human-Induced Effects on RSS Ranging Measurements for Cooperative Positioning

    DEFF Research Database (Denmark)

    Della Rosa, Francescantonio; Pelosi, Mauro; Nurmi, Jari

    2012-01-01

    We present experimental evaluations of human-induced perturbations on received-signal-strength-(RSS-) based ranging measurements for cooperative mobile positioning. To the best of our knowledge, this work is the first attempt to gain insight and understand the impact of both body loss and hand grip...... on the RSS for enhancing proximity measurements among neighbouring devices in cooperative scenarios. Our main contribution is represented by experimental investigations. Analysis of the errors introduced in the distance estimation using path-loss-based methods has been carried out. Moreover, the exploitation...... of human-induced perturbations for enhancing the final positioning accuracy through cooperative schemes has been assessed. It has been proved that the effect of cooperation is very limited if human factors are not taken into account when performing experimental activities....

  10. The Arctic zone: possibilities and risks of development

    Science.gov (United States)

    Sentsov, A.; Bolsunovskaya, Y.; Melnikovich, E.

    2016-09-01

    The authors analyze the Arctic region innovative possibilities from the perspective of political ideology and strategy. The Arctic region with its natural resources and high economic potential attracts many companies and it has become an important area of transnational development. At present, the Arctic region development is of great importance in terms of natural resource management and political system development. However, the most important development issue in the Arctic is a great risk of different countries’ competing interests in economic, political, and legal context. These are challenges for international partnership creating in the Arctic zone, Russian future model developing for the Arctic, and recognition of the Arctic as an important resource for the Russians. The Russian economic, military, and political expansion in the Arctic region has the potential to strengthen the national positions. The authors present interesting options for minimizing and eliminating political risks during the Arctic territories development and define an effective future planning model for the Russian Arctic.

  11. Arctic potential - Could more structured view improve the understanding of Arctic business opportunities?

    Science.gov (United States)

    Hintsala, Henna; Niemelä, Sami; Tervonen, Pekka

    2016-09-01

    The increasing interest towards the Arctic has been witnessed during the past decades. However, the commonly shared definitions of the Arctic key concepts have not yet penetrated national and international arenas for political and economic decision making. The lack of jointly defined framework has made different analyses related to the Arctic quite limited considering the magnitude of economic potential embedded in Arctic. This paper is built on the key findings of two separate, yet connected projects carried out in the Oulu region, Finland. In this paper's approach, the Arctic context has been defined as a composition of three overlapping layers. The first layer is the phenomenological approach to define the Arctic region. The second layer is the strategy-level analysis to define different Arctic paths as well as a national level description of a roadmap to Arctic specialization. The third layer is the operationalization of the first two layers to define the Arctic business context and business opportunities. The studied case from Oulu region indicates that alternative futures for the Arctic competences and business activities are in resemblance with only two of the four identified strategic pathways. Introduction of other pathways to regional level actors as credible and attractive options would require additional, systematic efforts.

  12. A direct pedestrian-structure interaction model to characterize the human induced vibrations on slender footbridges

    OpenAIRE

    Jiménez-Alonso, J. F.; Sáez, A.

    2014-01-01

    Although the scientific community had knowledge of the human induced vibration problems in structures since the end of the 19th century, it was not until the occurrence of the vibration phenomenon happened in the Millennium Bridge (London, 2000) that the importance of the problem revealed and a higher level of attention devoted. Despite the large advances achieved in the determination of the human-structure interaction force, one of the main deficiencies of the existing models is the exclusio...

  13. Arctic sea ice and Eurasian climate: A review

    OpenAIRE

    Gao, Yongqi; Sun, Jianqi; Li, Fei; He, Shengping; SANDVEN, Stein; Yan, Qing; Zhang, Zhongshi; LOHMANN, Katja; KEENLYSIDE, Noel; Furevik, Tore; Suo, Lingling

    2014-01-01

    The Arctic plays a fundamental role in the climate system and has shown significant climate change in recent decades, including the Arctic warming and decline of Arctic sea-ice extent and thickness. In contrast to the Arctic warming and reduction of Arctic sea ice, Europe, East Asia and North America have experienced anomalously cold conditions, with record snowfall during recent years. In this paper, we review current understanding of the sea-ice impacts on the Eurasian climate. Paleo, obser...

  14. Evolution of the Arctic Calanus complex: an Arctic marine avocado?

    Science.gov (United States)

    Berge, Jørgen; Gabrielsen, Tove M.; Moline, Mark; Renaud, Paul E.

    2012-01-01

    Before man hunted the large baleen whales to near extinction by the end of the nineteenth century, Arctic ecosystems were strongly influenced by these large predators. Their main prey were zooplankton, among which the calanoid copepod species of the genus Calanus, long considered key elements of polar marine ecosystems, are particularly abundant. These herbivorous zooplankters display a range of adaptations to the highly seasonal environments of the polar oceans, most notably extensive energy reserves and seasonal migrations to deep waters where the non-feeding season is spent in diapause. Classical work in marine ecology has suggested that slow growth, long lifespan and large body size in zooplankton are specific adaptations to life in cold waters with short and unpredictable feeding seasons. Here, we challenge this understanding and, by using an analogy from the evolutionary and contemporary history of the avocado, argue that predation pressure by the now nearly extinct baleen whales was an important driving force in the evolution of life history diversity in the Arctic Calanus complex. PMID:22312184

  15. Arctic warming, moisture increase and circulation changes observed in the Ny-Ålesund homogenized radiosonde record

    Science.gov (United States)

    Maturilli, Marion; Kayser, Markus

    2017-04-01

    Compared to global warming, the feedback mechanisms of Arctic Amplification lead to an increase of surface temperature in the Arctic by a factor of two. Yet, the vertical structure of Arctic warming and its resulting radiative feedbacks are poorly understood. Here, we focus on the analysis of the atmospheric column above Ny-Ålesund (78.9° N, 11.9° E), Svalbard. At Ny-Ålesund, radiosondes have been launched on a daily basis since 1993 in support of synoptic observations. The obtained radiosonde measurements 1993 to 2014 have been homogenized accounting for instrumentation discontinuities and known errors in the manufacturer provided profiles. From the homogenized data record, a first upper-air climatology of wind, humidity and temperature above Ny-Ålesund is presented, forming the background for the analysis of changes detected during the 22-year period. Particularly during the winter season, a strong increase in atmospheric humidity and temperature is observed, with a significant warming of the free troposphere in January and February of up to 3 K per decade. This winter warming is even more pronounced in the boundary layer below 1 km, presumably amplified by local conditions including e.g. orographic effects or the boundary layer capping inversion. Also the largest contribution to the increasing atmospheric water vapour column originates from the lowermost 2 km of the atmosphere where specific humidity inversions are frequently observed. Yet, no increase in the water vapour contribution by humidity inversions is detected. Instead, we find an increase in the humidity content of the large scale background humidity profiles to be responsible for the observed increase in winter integrated water vapour. The observed difference in the frequency occurrence of wind directions in the free troposphere between the first and second half of the 22-year period implies that the large scale synoptic flow over Svalbard has changed over the years. During the winter season, the

  16. Diagnostic sea ice predictability in the pan-Arctic and U.S. Arctic regional seas

    Science.gov (United States)

    Cheng, Wei; Blanchard-Wrigglesworth, Edward; Bitz, Cecilia M.; Ladd, Carol; Stabeno, Phyllis J.

    2016-11-01

    This study assesses sea ice predictability in the pan-Arctic and U.S. Arctic regional (Bering, Chukchi, and Beaufort) seas with a purpose of understanding regional differences from the pan-Arctic perspective and how predictability might change under changing climate. Lagged correlation is derived using existing output from the Community Earth System Model Large Ensemble (CESM-LE), Pan-Arctic Ice-Ocean Modeling and Assimilation System, and NOAA Coupled Forecast System Reanalysis models. While qualitatively similar, quantitative differences exist in Arctic ice area lagged correlation in models with or without data assimilation. On regional scales, modeled ice area lagged correlations are strongly location and season dependent. A robust feature in the CESM-LE is that the pan-Arctic melt-to-freeze season ice area memory intensifies, whereas the freeze-to-melt season memory weakens as climate warms, but there are across-region variations in the sea ice predictability changes with changing climate.

  17. THE ARCTIC: A DIALOGUE FOR DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Yury Mazurov

    2010-01-01

    Full Text Available In September 2010, Moscow hosted the International Arctic Forum “The Arctic—Territory of Dialogue.” The Arctic Forum focused its attention on elements of sustainable development in the Arctic region, i.e., ecology, economics, infrastructure, social services, security, and geopolitics. Many Russian experts and many well-known politicians and experts from leading research centers of the Arctic countries (Canada, Denmark, Finland, Iceland, Norway, Sweden, and USA, as well as by participants from France, Germany, Netherlands, and other countries attended the forum. Scholars and public figures from the European countries, representatives of the NATO, the Organization for Security and Cooperation in Europe and other institutions were also present at the conference. In his key-note speech the Chairman of the Board of Trustees of the Russian Geographical Society (RGS, Prime Minister of the Russian Federation, Vladimir V. Putin formulated the principles of Russian national policy in the Arctic. Russian and foreign participants supported the idea of continuing dialogue on the Arctic under the RGS’s aegis and the transformation of the Arctic Forum into a permanent platform for discussions on the most urgent issues of the region.

  18. Arctic Collaborative Environment: A New Multi-National Partnership for Arctic Science and Decision Support

    Science.gov (United States)

    Laymon, Charles A,; Kress, Martin P.; McCracken, Jeff E.; Spehn, Stephen L.; Tanner, Steve

    2011-01-01

    The Arctic Collaborative Environment (ACE) project is a new international partnership for information sharing to meet the challenges of addressing Arctic. The goal of ACE is to create an open source, web-based, multi-national monitoring, analysis, and visualization decision-support system for Arctic environmental assessment, management, and sustainability. This paper will describe the concept, system architecture, and data products that are being developed and disseminated among partners and independent users through remote access.

  19. Survival strategies in arctic ungulates

    Directory of Open Access Journals (Sweden)

    N. J. C. Tyler

    1990-09-01

    Full Text Available Arctic ungulates usually neither freeze nor starve to death despite the rigours of winter. Physiological adaptations enable them to survive and reproduce despite long periods of intense cold and potential undernutrition. Heat conservation is achieved by excellent insulation combined with nasal heat exchange. Seasonal variation in fasting metabolic rate has been reported in several temperate and sub-arctic species of ungulates and seems to occur in muskoxen. Surprisingly, there is no evidence for this in reindeer. Both reindeer and caribou normally maintain low levels of locomotor activity in winter. Light foot loads are important for reducing energy expenditure while walking over snow. The significance and control of selective cooling of the brain during hard exercise (e.g. escape from predators is discussed. Like other cervids, reindeer and caribou display a pronounced seasonal cycle of appetite and growth which seems to have an intrinsic basis. This has two consequences. First, the animals evidently survive perfectly well despite enduring negative energy balance for long periods. Second, loss of weight in winter is not necessarily evidence of undernutrition. The main role of fat reserves, especially in males, may be to enhance reproductive success. The principal role of fat reserves in winter appears to be to provide a supplement to, rather than a substitute for, poor quality winter forage. Fat also provides an insurance against death during periods of acute starvation.

  20. Heat flow in the Arctic

    Science.gov (United States)

    Lachenbruch, Arthur H.; Marshall, B. Vaughan

    1969-01-01

    Defines heat flow as the flux at the earth's solid surface of heat conducted from the interior; the heat-flow-unit (hfu) is on the order of 1-millionth calorie through each sq cm of the surface/sec, which is enough to melt a 4-mm layer of ice over the earth's surface/yr. Earth heat originates from radioactive decay of U, Th and K in the crust and mantle. Although land heat-flow measurements in the Arctic are too few for regional interpretation, those from Cape Thompson, Barrow and Cape Simpson, Northern Alaska are discussed and figured to show what they contribute to understanding of permafrost, climatic change and shoreline movements. Measuring thermal conductivity and gradient is much simpler in ocean basins than on land. Locations of such measurements are mapped, the results for the Alaskan quadrant in more detail. The sharp change in heat flow at the edge of the Alpha Cordillera, shown in a geothermal model, suggests that this feature is a huge accumulation of basalt, rather than mantle material or remnant of a foundering continent as previously postulated. Future Arctic heat flow studies are discussed.

  1. An overview of Arctic Ocean acoustics

    Science.gov (United States)

    Hutt, Dan

    2012-11-01

    This paper presents a review of the underwater acoustics of the Arctic Ocean. It discusses the main features of the underwater acoustic environment and how they are so strongly affected by the presence of ice cover. The paper also discusses the history of Arctic Ocean acoustics research, how the motivation was originally military in character during the Cold War and how it changed to being driven by environmental considerations today. Originally, the physics of the Arctic Ocean was studied in order to predict its acoustic properties, and now acoustic techniques are used to help understand its physical environment.

  2. Politics of sustainability in the Arctic (POSUSA)

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram; Jakobsen, Uffe; Strandsbjerg, Jeppe

    The concept of sustainability is of central importance in Arctic politics. However, for different actors (governments, indigenious peoples, NGOs) the concept implies different sets of precautions and opportunities. Sustainability, therefore, is much more a fundamental concept to be further...... elaborated than a definable term with a specific meaning. This is the core hypothesis in a collective research project, the POSUSA project (Politics of Sustainability in the Arctic) that aims to map and analyse the role of sustainability in various political and economic strategies in the Arctic....

  3. Introduction: World Routes in the Arctic

    Directory of Open Access Journals (Sweden)

    Art Leete

    2011-12-01

    Full Text Available The Arctic is associated in popular perception with a vast frozen snow covered empty place. Everybody who has been in the Arctic, whether in the Eurasian or North American part, knows that this stereotype is correct. Indeed, the Arctic is a place with lots of space that determines the lifestyle of the people in this area. All human activities – whether livelihood or mastering of the territory– are and always have been connected with substantial movement. Hunting, fishing, trading, the establishment of settlements and keeping them alive, all this needs the movement of goods and human resources.

  4. Politics of sustainability in the Arctic (POSUSA)

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram; Jakobsen, Uffe; Strandsbjerg, Jeppe

    elaborated than a definable term with a specific meaning. This is the core hypothesis in a collective research project, the POSUSA project (Politics of Sustainability in the Arctic) that aims to map and analyse the role of sustainability in various political and economic strategies in the Arctic.......The concept of sustainability is of central importance in Arctic politics. However, for different actors (governments, indigenious peoples, NGOs) the concept implies different sets of precautions and opportunities. Sustainability, therefore, is much more a fundamental concept to be further...

  5. Arctic ecosystem responses to a warming climate

    DEFF Research Database (Denmark)

    Mortensen, Lars O.

    is frozen solid for the main part of the year. However, in recent decades, arctic temperatures have in-creased between two and three times that of the global averages, which have had a substantial impact on the physical environment of the arctic ecosystem, such as deglaciation of the Greenland inland ice...... sheet, loss of multiannual sea-ice and significant advances in snowmelt days. The biotic components of the arctic ecosystem have also been affected by the rapid changes in climate, for instance resulting in the collapse of the collared lemming cycle, advances in spring flowering and changes in the intra...

  6. A temperate intertidal key species in the Arctic – how a non-arctic species survive and perform in a changing Arctic

    DEFF Research Database (Denmark)

    Thyrring, Jakob

    The Arctic is experiencing accelerated warming. Increasing temperature is known to affect species distribution and abundance but knowledge about the impacts on Arctic marine biogeography remains limited. Blue mussels (genus Mytilus) constitute a key ecological role in the littoral zone...

  7. Impact of Cell Composition and Geometry on Human Induced Pluripotent Stem Cells-Derived Engineered Cardiac Tissue

    National Research Council Canada - National Science Library

    Takeichiro Nakane; Hidetoshi Masumoto; Joseph P Tinney; Fangping Yuan; William J Kowalski; Fei Ye; Amanda J Leblanc; Ryuzo Sakata; Jun K Yamashita; Bradley B Keller

    2017-01-01

    ...) composed of human induced pluripotent stem cells (hiPSCs) derived multiple lineage cardiac cells with varied 3D geometries and cell densities developed towards the goal of scale-up for large animal pre-clinical studies...

  8. Revegetation techniques in arctic and subarctic environments

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the revegetation techniques in the arctic and subarctic environments. Background on the subject, as well as a literature reviews concerning...

  9. Boundary survey, Arctic National Wildlife Range

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is on the geology of the Arctic National Wildlife Range western boundary. The Canning River region and Southern Brooks range are both analyzed, including...

  10. Arctic parasitology: why should we care?

    Science.gov (United States)

    Davidson, Rebecca; Simard, Manon; Kutz, Susan J; Kapel, Christian M O; Hamnes, Inger S; Robertson, Lucy J

    2011-06-01

    The significant impact on human and animal health from parasitic infections in tropical regions is well known, but parasites of medical and veterinary importance are also found in the Arctic. Subsistence hunting and inadequate food inspection can expose people of the Arctic to foodborne parasites. Parasitic infections can influence the health of wildlife populations and thereby food security. The low ecological diversity that characterizes the Arctic imparts vulnerability. In addition, parasitic invasions and altered transmission of endemic parasites are evident and anticipated to continue under current climate changes, manifesting as pathogen range expansion, host switching, and/or disease emergence or reduction. However, Arctic ecosystems can provide useful models for understanding climate-induced shifts in host-parasite ecology in other regions.

  11. Centennial Valley Arctic Grayling Adaptive Management Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Montana Arctic grayling (grayling) were patchily distributed throughout the Upper Missouri River (UMR) drainage prior to the mid-1850's. This population declined to...

  12. Acoustic Resonance Reaction Control Thruster (ARCTIC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate the innovative Acoustic Resonance Reaction Control Thruster (ARCTIC) to provide rapid and reliable in-space impulse...

  13. Arctic National Wildlife Range: Master plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is the master plan for Arctic National Wildlife Refuge. This plan outlines refuge objectives, history, existing conditions, and proposed accomplishments for the...

  14. Narrative report 1970 : Arctic National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Arctic NWR outlines Refuge accomplishments during the 1970 calendar year. Wildlife- including migratory birds, upland game birds,...

  15. Geologic Provinces of the Arctic, 2000 (prvarcst)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons and polygon labels that describe Arctic portion of the U.S. Geological Survey defined geologic provinces of the World in 2000.

  16. Arctic climate change: Greenhouse warming unleashed

    Science.gov (United States)

    Mauritsen, Thorsten

    2016-04-01

    Human activity alters the atmospheric composition, which leads to global warming. Model simulations suggest that reductions in emission of sulfur dioxide from Europe since the 1970s could have unveiled rapid Arctic greenhouse gas warming.

  17. Arctic Marine Transportation Program 1979-1986

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this program was to collect data relevant to developing year-round transportation capabilities in the Arctic Ocean. The US Maritime Administration...

  18. Arctic Landfast Sea Ice 1953-1998

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The files in this data set contain landfast sea ice data (monthly means) gathered from both Russian Arctic and Antarctic Research Institute (AARI) and Canadian Ice...

  19. Biogeochemistry: Arctic plants take up mercury vapour

    Science.gov (United States)

    Shotyk, William

    2017-07-01

    Trace elements are enriched in plants by natural processes, human activities or both. An analysis of mercury in Arctic tundra vegetation offers fresh insight into the uptake of trace metals from the atmosphere by plants. See Letter p.201

  20. Atmospheric dynamics: Arctic winds of change

    Science.gov (United States)

    Notz, Dirk

    2016-09-01

    The Earth's climate evolves in response to both externally forced changes and internal variability. Now research suggests that both drivers combine to set the pace of Arctic warming caused by large-scale sea-ice loss.

  1. Loss of sea ice in the Arctic.

    Science.gov (United States)

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2009-01-01

    The Arctic sea ice cover is in decline. The areal extent of the ice cover has been decreasing for the past few decades at an accelerating rate. Evidence also points to a decrease in sea ice thickness and a reduction in the amount of thicker perennial sea ice. A general global warming trend has made the ice cover more vulnerable to natural fluctuations in atmospheric and oceanic forcing. The observed reduction in Arctic sea ice is a consequence of both thermodynamic and dynamic processes, including such factors as preconditioning of the ice cover, overall warming trends, changes in cloud coverage, shifts in atmospheric circulation patterns, increased export of older ice out of the Arctic, advection of ocean heat from the Pacific and North Atlantic, enhanced solar heating of the ocean, and the ice-albedo feedback. The diminishing Arctic sea ice is creating social, political, economic, and ecological challenges.

  2. Sea ice thickness and recent Arctic warming

    Science.gov (United States)

    Lang, Andreas; Yang, Shuting; Kaas, Eigil

    2017-01-01

    The climatic impact of increased Arctic sea ice loss has received growing attention in the last years. However, little focus has been set on the role of sea ice thickness, although it strongly determines surface heat fluxes. Here ensembles of simulations using the EC-Earth atmospheric model (Integrated Forecast System) are performed and analyzed to quantify the atmospheric impacts of Arctic sea ice thickness change since 1982 as revealed by the sea ice model assimilation Global Ice-Ocean Modeling and Assimilation System. Results show that the recent sea ice thinning has significantly affected the Arctic climate, while remote atmospheric responses are less pronounced owing to a high internal atmospheric variability. Locally, the sea ice thinning results in enhancement of near-surface warming of about 1°C per decade in winter, which is most pronounced over marginal sea ice areas with thin ice. This leads to an increase of the Arctic amplification factor by 37%.

  3. Methane from the East Siberian Arctic shelf

    DEFF Research Database (Denmark)

    Petrenko...[], Vasilii V.; Etheridge, David M.

    2010-01-01

    that the release of Arctic CH4 was implied in previous climate shifts as well as in the recently renewed rise in atmospheric CH4. These claims are not supported by all the literature they cite. Their reference 5 (1) presents measurements of emissions only of carbon dioxide, not CH4. Their reference 8 (2), a study...... that is changing in response to Arctic warming. Shakhova et al. do acknowledge these distinctions, but in these times of enhanced scrutiny of climate change science, it is important to communicate all evidence to the scientific community and the public clearly and accurately......In their Report “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf” (5 March, p. 1246), N. Shakhova et al. write that methane (CH4) release resulting from thawing Arctic permafrost “is a likely positive feedback to climate warming.” They add...

  4. Arctic National Wildlife Range, Annual Narrative Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Arctic National Wildlife Range (ANWR) was established by executive order in 1960 for the purpose of preserving unique wildlife, wilderness and recreational...

  5. Arctic and Aleutian terns, Amchitka Island, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Baird (1980) has recently reported on the ecology of Arctic terns (Sterna paradisaea) and Aleutian terns (Sterna aleutica) from 4 areas of mainland Alaska. However,...

  6. Arctic and Southern Ocean Sea Ice Concentrations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly sea ice concentration for Arctic (1901 to 1995) and Southern oceans (1973 to 1990) were digitized on a standard 1-degree grid (cylindrical projection) to...

  7. Influence on ICC Treated with Self-Prepared Formula for Removing Stasis and Moistening the Intestine for the Mouse Model with Intractable Constipation%自拟化瘀润肠方对顽固性便秘模型小鼠结肠间质细胞的影响

    Institute of Scientific and Technical Information of China (English)

    李国峰

    2011-01-01

    目的 探讨化瘀润肠方治疗便秘的机理.方法 采用吗啡皮下注射方法复制顽固性便秘小鼠模型,观察便秘模型小鼠是否存在结肠间质细胞(ICC)的变化,通过药物治疗后是否会恢复ICC的功能和结构.结果 便秘模型小鼠与空白组小鼠比较,ICC数量明显减少(P<0.05),各药物组与模型组比较,小鼠结肠ICC数量均有提高(P<0.05),但化瘀润肠方大剂量组作用程度明显优于中剂量组(P<0.05),中剂量组明显优于麻仁软胶囊组(P<0.05),麻仁软胶囊组优于莫沙比利组(P<0.05),莫沙比利组与化瘀润肠方小剂量组比较,差异无统计学意义(P>0.05).免疫荧光与激光共聚焦显微镜扫描观察小鼠结肠ICC变化,发现化瘀润肠方中、大剂量组能够恢复便秘小鼠ICC结构.结论 便秘模型小鼠结肠ICC存在形态及数量异常,化瘀润肠方能够增加便秘模型小鼠结肠ICC的数量.%Objective To explore the mechanism on constipation treated with the formula for removing stasis and moistening the intestine. Methods The subcutaneous injection of morphine was adopted to duplicate the mouse models of intractable constipation. It was to observe whether the changes of interstitial cells of Cajal( ICC )were induced and whether the function and structure of ICC were recovered after treatment. Results In comparison with the mice in blank group, ICC count for the constipation models decreased obviously( P < 0.05 ). In comparison between every medication group and model group, ICC count was all up - regulated( P <0.05 ). But concerning to the function extent,the result in large - dose group with the formula for removing stasis and moistening the intestine was superior apparently to that in middle - dose group( P < 0.05 ). The result in middle - dose group was superior apparently to that in fructus cannabis capsule group( P < 0.05 ). The result in fructus cannabis capsule group was better than that in mosapride group( P

  8. Simulation of Human-induced Vibrations Based on the Characterized In-field Pedestrian Behavior.

    Science.gov (United States)

    Van Nimmen, Katrien; Lombaert, Geert; De Roeck, Guido; Van den Broeck, Peter

    2016-04-13

    For slender and lightweight structures, vibration serviceability is a matter of growing concern, often constituting the critical design requirement. With designs governed by the dynamic performance under human-induced loads, a strong demand exists for the verification and refinement of currently available load models. The present contribution uses a 3D inertial motion tracking technique for the characterization of the in-field pedestrian behavior. The technique is first tested in laboratory experiments with simultaneous registration of the corresponding ground reaction forces. The experiments include walking persons as well as rhythmical human activities such as jumping and bobbing. It is shown that the registered motion allows for the identification of the time variant pacing rate of the activity. Together with the weight of the person and the application of generalized force models available in literature, the identified time-variant pacing rate allows to characterize the human-induced loads. In addition, time synchronization among the wireless motion trackers allows identifying the synchronization rate among the participants. Subsequently, the technique is used on a real footbridge where both the motion of the persons and the induced structural vibrations are registered. It is shown how the characterized in-field pedestrian behavior can be applied to simulate the induced structural response. It is demonstrated that the in situ identified pacing rate and synchronization rate constitute an essential input for the simulation and verification of the human-induced loads. The main potential applications of the proposed methodology are the estimation of human-structure interaction phenomena and the development of suitable models for the correlation among pedestrians in real traffic conditions.

  9. Studying ocean acidification in the Arctic Ocean

    Science.gov (United States)

    Robbins, Lisa

    2012-01-01

    The U.S. Geological Survey (USGS) partnership with the U.S. Coast Guard Ice Breaker Healey and its United Nations Convention Law of the Sea (UNCLOS) cruises has produced new synoptic data from samples collected in the Arctic Ocean and insights into the patterns and extent of ocean acidification. This framework of foundational geochemical information will help inform our understanding of potential risks to Arctic resources due to ocean acidification.

  10. Thin-ice Arctic Acoustic Window (THAAW)

    Science.gov (United States)

    2014-09-30

    STATEMENT A. Approved for public release; distribution is unlimited. Thin- ice Arctic Acoustic Window (THAAW) Peter F. Worcester Scripps Institution of...of the ice cover and extensive warming of the intermediate layers. The multiyear ice is melting . Ice keels are getting smaller. With more open water...determine the fundamental limits to signal processing in the Arctic imposed by ocean and ice processes. The hope is that these first few new steps will

  11. ONR Chair in Arctic Marine Science

    Science.gov (United States)

    2016-06-07

    his measurements of ice thickness and heat/salt flux in Terra Nova Bay Polynya should pave the way for new parameterizations of ice growth/ melt in...SEP 1999 2. REPORT TYPE 3. DATES COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE ONR Chair in Arctic Marine Science 5a. CONTRACT... Arctic Marine Science Robert H. Bourke Department of Oceanography Naval Postgraduate School 833 Dyer Road, Bldg. 232, Rm. 328 Monterey, CA 93943

  12. Coarse mode aerosols in the High Arctic

    Science.gov (United States)

    Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.

    2014-12-01

    Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

  13. Understanding Tropospheric Ozone Variability in the Arctic

    Science.gov (United States)

    McClure-Begley, A.; Petropavlovskikh, I. V.; Crepinsek, S.; Uttal, T.; Skov, H.

    2016-12-01

    The Arctic is a region that has been subject to drastic changes in the climate partially due to transported pollutants which strongly impact the composition of the atmosphere and associated feedbacks. Tropospheric ozone is an atmospheric species formed by the reaction of precursor species (NOx, CO, VOC's) in the presence of UV radiation and drives complex interactions which can result in impacts on atmospheric conditions in the Arctic. As an important greenhouse gas, ozone has a significant influence on the photochemical characteristics, oxidation capacity, and radiative forcing of the atmosphere and at high levels has negative impacts on public health and overall ecosystem functioning. In the Arctic, tropospheric ozone has variable characteristics in time and space. Seasonal variation of ozone is controlled by many factors influencing the production and destruction of ozone. The arctic ozone conditions are strongly influenced by seasonal destruction events, arctic haze, transport of pollution from Asia and influence from precursor compounds released from wildfires. This study investigates long-term ozone variation, seasonal surface ozone conditions, and characterizes deviations from expected ozone levels at four arctic ozone measurement locations (Barrow Alaska, Tiksi Russia, Summit Greenland, and Villum Station Greenland). Frequency of ozone depletion events and high ozone episodes for each station over time provides a context for the changing conditions of ozone in the arctic. NOAA Hysplit back-trajectory analysis, satellite imagery, NOAA Smoke verification model, co-located carbon monoxide, carbon dioxide, and aerosol optical depth measurements are used to understand the dominant source of pollution, pollutant composition, and the interactions due to meteorological conditions that result in anomalies in the ozone mixing ratio records. Characterization of ozone behavior and influences on the measurement locations is essential for understanding the spatial and

  14. Vertical structure of recent Arctic warming.

    Science.gov (United States)

    Graversen, Rune G; Mauritsen, Thorsten; Tjernström, Michael; Källén, Erland; Svensson, Gunilla

    2008-01-03

    Near-surface warming in the Arctic has been almost twice as large as the global average over recent decades-a phenomenon that is known as the 'Arctic amplification'. The underlying causes of this temperature amplification remain uncertain. The reduction in snow and ice cover that has occurred over recent decades may have played a role. Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar warming. Reduction of the snow and ice cover causes albedo changes, and increased refreezing of sea ice during the cold season and decreases in sea-ice thickness both increase heat flux from the ocean to the atmosphere. Changes in oceanic and atmospheric circulation, as well as cloud cover, have also been proposed to cause Arctic temperature amplification. Here we examine the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data. We find evidence for temperature amplification well above the surface. Snow and ice feedbacks cannot be the main cause of the warming aloft during the greater part of the year, because these feedbacks are expected to primarily affect temperatures in the lowermost part of the atmosphere, resulting in a pattern of warming that we only observe in spring. A significant proportion of the observed temperature amplification must therefore be explained by mechanisms that induce warming above the lowermost part of the atmosphere. We regress the Arctic temperature field on the atmospheric energy transport into the Arctic and find that, in the summer half-year, a significant proportion of the vertical structure of warming can be explained by changes in this variable. We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification.

  15. The remote sensing needs of Arctic geophysics

    Science.gov (United States)

    Campbell, W. J.

    1970-01-01

    The application of remote sensors for obtaining geophysical information of the Arctic regions is discussed. Two significant requirements are to acquire sequential, synoptic imagery of the Arctic Ocean during all weather and seasons and to measure the strains in the sea ice canopy and the heterogeneous character of the air and water stresses acting on the canopy. The acquisition of geophysical data by side looking radar and microwave sensors in military aircraft is described.

  16. Arctic Freshwater Ice and Its Climatic Role

    OpenAIRE

    Prowse, Terry; Alfredsen, Knut; Beltaos, Spyros; Bonsal, Barrie; Duguay, Claude; Korhola, Atte; McNamara, Jim; Vincent, Warwick F.; Vuglinsky, Valery; Weyhenmeyer, Gesa A.

    2011-01-01

    Freshwater ice dominates the Arctic terrestrial environment and significantly impacts bio-physical and socio-economic systems. Unlike other major cryospheric components that either blanket large expanses (e.g., snow, permafrost, sea ice) or are concentrated in specific locations, lake and river ice are interwoven into the terrestrial landscape through major flow and storage networks. For instance, the headwaters of large ice-covered rivers extend well beyond the Arctic while many northern lak...

  17. Speciation in arctic and alpine diploid plants

    OpenAIRE

    Gustafsson, A Lovisa S

    2013-01-01

    The main objectives of this thesis are to study patterns and processes of plant speciation in arctic and alpine diploid plants. Cryptic species are here referred to as morphologically similar individuals belonging to the same taxonomic species but that are unable to produce fertile offspring (i.e. 'sibling' species). The arctic flora is considered as one of the most species-poor floras of the world, and the latitudinal gradient with decreasing diversity from low to high latitudes is likely...

  18. Redefining U.S. Arctic Strategy

    Science.gov (United States)

    2015-05-15

    52 Xie, Kevin. Some BRICS in the Arctic: Developing Powers Look North, Harvard International Review, Vol 36, No. 3, Spring 2015. Accessed 11...May 2015 at <https://www.questia.com/library/journal/1G1- 411013832/some- brics -in-the-arctic-developing-powers-look-north> 18 Strategy for the...2013. Vego, Milan. Joint Operational Warfare, Theory and Practice. Newport, RI: U.S. Naval War College, 2009. Xie, Kevin. Some BRICS in the

  19. Arctic ecosystem responses to a warming climate

    DEFF Research Database (Denmark)

    Mortensen, Lars O.

    is frozen solid for the main part of the year. However, in recent decades, arctic temperatures have in-creased between two and three times that of the global averages, which have had a substantial impact on the physical environment of the arctic ecosystem, such as deglaciation of the Greenland inland ice......’ of ecosystem re-sponses to the future global climate change....

  20. Migration and breeding biology of arctic terns in Greenland

    DEFF Research Database (Denmark)

    Egevang, Carsten

    (Sandøen) in high-Arctic Northeast Greenland. The level of knowledge of the Arctic tern in Greenland before 2002 was to a large extent poor, with aspects of its biology being completely unknown in the Greenland population. This thesis presents novel findings for the Arctic tern, both on an international...... by the distribution of breeding Arctic terns as suggested by Egevang et al. (2004). Included in the thesis are furthermore results with an appeal to the Greenland management agencies. Along with estimates of the Arctic tern population size at the two most important Arctic tern colonies in West Greenland and East...

  1. The Vulnerability of Earth Systems to Human-Induced Global Change and Strategies for Mitigation

    Science.gov (United States)

    Watson, R. T.

    2002-12-01

    Since the IGY, there has been growing evidence that climate is changing in response to human activities. The overwhelming majority of scientific experts, whilst recognizing that scientific uncertainties exist, nonetheless believe that human-induced climate change is inevitable. Indeed, during the last few years, many parts of the world have suffered major heat waves, floods, droughts, fires and extreme weather events leading to significant economic losses and loss of life. While individual events cannot be directly linked to human-induced climate change, the frequency and magnitude of these types of events are predicted to increase in a warmer world. The question is not whether climate will change, but rather how much (magnitude), how fast (the rate of change) and where (regional patterns). It is also clear that climate change and other human-induced modifications to the environment will, in many parts of the world, adversely affect socio-economic sectors, including water resources, agriculture, forestry, fisheries and human settlements, ecological systems (particularly forests and coral reefs), and human health (particularly diseases spread by insects), with developing countries being the most vulnerable. Environmental degradation of all types (i.e., climate change, loss of biodiversity, land degradation, air and water quality) all undermine the challenge of poverty alleviation and sustainable economic growth. One of the major challenges facing humankind is to provide an equitable standard of living for this and future generations: adequate food, water and energy, safe shelter and a healthy environment (e.g., clean air and water). Unfortunately, human-induced climate change, as well as other global environmental issues such as land degradation, loss of biological diversity and stratospheric ozone depletion, threatens our ability to meet these basic human needs. The good news is, however, that the majority of experts believe that significant reductions in net

  2. Differentiation of Human Induced Pluripotent Stem Cells to Mammary-like Organoids

    OpenAIRE

    Ying Qu; Bingchen Han; Bowen Gao; Shikha Bose; Yiping Gong; Kolja Wawrowsky; Giuliano, Armando E.; Dhruv Sareen; Xiaojiang Cui

    2017-01-01

    Human induced pluripotent stem cells (iPSCs) can give rise to multiple cell types and hold great promise in regenerative medicine and disease-modeling applications. We have developed a reliable two-step protocol to generate human mammary-like organoids from iPSCs. Non-neural ectoderm-cell-containing spheres, referred to as mEBs, were first differentiated and enriched from iPSCs using MammoCult medium. Gene expression profile analysis suggested that mammary gland function-associated signaling ...

  3. Differentiation of Human Induced Pluripotent Stem Cells to Mammary-like Organoids

    OpenAIRE

    Qu, Ying; Han, Bingchen; Gao, Bowen; Bose, Shikha; Gong, Yiping; Wawrowsky, Kolja; Giuliano, Armando E.; Sareen, Dhruv; Cui, Xiaojiang

    2017-01-01

    Summary Human induced pluripotent stem cells (iPSCs) can give rise to multiple cell types and hold great promise in regenerative medicine and disease-modeling applications. We have developed a reliable two-step protocol to generate human mammary-like organoids from iPSCs. Non-neural ectoderm-cell-containing spheres, referred to as mEBs, were first differentiated and enriched from iPSCs using MammoCult medium. Gene expression profile analysis suggested that mammary gland function-associated si...

  4. Establishment of Human Neural Progenitor Cells from Human Induced Pluripotent Stem Cells with Diverse Tissue Origins

    Science.gov (United States)

    Fukusumi, Hayato; Shofuda, Tomoko; Bamba, Yohei; Yamamoto, Atsuyo; Kanematsu, Daisuke; Handa, Yukako; Okita, Keisuke; Nakamura, Masaya; Yamanaka, Shinya; Okano, Hideyuki; Kanemura, Yonehiro

    2016-01-01

    Human neural progenitor cells (hNPCs) have previously been generated from limited numbers of human induced pluripotent stem cell (hiPSC) clones. Here, 21 hiPSC clones derived from human dermal fibroblasts, cord blood cells, and peripheral blood mononuclear cells were differentiated using two neural induction methods, an embryoid body (EB) formation-based method and an EB formation method using dual SMAD inhibitors (dSMADi). Our results showed that expandable hNPCs could be generated from hiPSC clones with diverse somatic tissue origins. The established hNPCs exhibited a mid/hindbrain-type neural identity and uniform expression of neural progenitor genes. PMID:27212953

  5. Establishment of Human Neural Progenitor Cells from Human Induced Pluripotent Stem Cells with Diverse Tissue Origins.

    Science.gov (United States)

    Fukusumi, Hayato; Shofuda, Tomoko; Bamba, Yohei; Yamamoto, Atsuyo; Kanematsu, Daisuke; Handa, Yukako; Okita, Keisuke; Nakamura, Masaya; Yamanaka, Shinya; Okano, Hideyuki; Kanemura, Yonehiro

    2016-01-01

    Human neural progenitor cells (hNPCs) have previously been generated from limited numbers of human induced pluripotent stem cell (hiPSC) clones. Here, 21 hiPSC clones derived from human dermal fibroblasts, cord blood cells, and peripheral blood mononuclear cells were differentiated using two neural induction methods, an embryoid body (EB) formation-based method and an EB formation method using dual SMAD inhibitors (dSMADi). Our results showed that expandable hNPCs could be generated from hiPSC clones with diverse somatic tissue origins. The established hNPCs exhibited a mid/hindbrain-type neural identity and uniform expression of neural progenitor genes.

  6. Arctic Ocean data in CARINA

    Directory of Open Access Journals (Sweden)

    S. Jutterström

    2009-08-01

    Full Text Available The paper describes the steps taken for quality controlling chosen parameters within the Arctic Ocean data included in the CARINA data set and checking for offsets between the individual cruises. The evaluated parameters are the inorganic carbon parameters (total dissolved inorganic carbon, total alkalinity and pH, oxygen and nutrients: nitrate, phosphate and silicate. More parameters can be found in the CARINA data product, but were not subject to a secondary quality control. The main method in determining offsets between cruises was regional multi-linear regression, after a first rough basin-wide deep-water estimate of each parameter. Lastly, the results of the secondary quality control are discussed as well as suggested adjustments.

  7. Arctic Ocean data in CARINA

    Directory of Open Access Journals (Sweden)

    S. Jutterström

    2010-02-01

    Full Text Available The paper describes the steps taken for quality controlling chosen parameters within the Arctic Ocean data included in the CARINA data set and checking for offsets between the individual cruises. The evaluated parameters are the inorganic carbon parameters (total dissolved inorganic carbon, total alkalinity and pH, oxygen and nutrients: nitrate, phosphate and silicate. More parameters can be found in the CARINA data product, but were not subject to a secondary quality control. The main method in determining offsets between cruises was regional multi-linear regression, after a first rough basin-wide deep-water estimate of each parameter. Lastly, the results of the secondary quality control are discussed as well as applied adjustments.

  8. The great challenges in Arctic Ocean paleoceanography

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Ruediger, E-mail: Ruediger.Stein@awi.de [Alfred Wegener Institute for Polar and Marine Research, 27568 Bremerhaven (Germany)

    2011-05-15

    Despite the importance of the Arctic in the climate system, the data base we have from this area is still very weak, and large parts of the climate history have not been recovered at all in sedimentary sections. In order to fill this gap in knowledge, international, multidisciplinary expeditions and projects for scientific drilling/coring in the Arctic Ocean are needed. Key areas and approaches for drilling and recovering undisturbed and complete sedimentary sequences are depth transects across the major ocean ridge systems, i.e., the Lomonosov Ridge, the Alpha-Mendeleev Ridge, and the Chukchi Plateau/Northwind Ridge, the Beaufort, Kara and Laptev sea continental margins, as well as the major Arctic gateways towards the Atlantic and Pacific oceans. The new detailed climate records from the Arctic Ocean spanning time intervals from the Late Cretaceous/Paleogene Greenhouse world to the Neogene-Quaternary Icehouse world and representing short- and long-term climate variability on scales from 10 to 10{sup 6} years, will give new insights into our understanding of the Arctic Ocean within the global climate system and provide an opportunity to test the performance of climate models used to predict future climate change. With this, studying the Arctic Ocean is certainly one of the major challenges in climate research for the coming decades.

  9. Influence of sea ice on Arctic precipitation.

    Science.gov (United States)

    Kopec, Ben G; Feng, Xiahong; Michel, Fred A; Posmentier, Eric S

    2016-01-05

    Global climate is influenced by the Arctic hydrologic cycle, which is, in part, regulated by sea ice through its control on evaporation and precipitation. However, the quantitative link between precipitation and sea ice extent is poorly constrained. Here we present observational evidence for the response of precipitation to sea ice reduction and assess the sensitivity of the response. Changes in the proportion of moisture sourced from the Arctic with sea ice change in the Canadian Arctic and Greenland Sea regions over the past two decades are inferred from annually averaged deuterium excess (d-excess) measurements from six sites. Other influences on the Arctic hydrologic cycle, such as the strength of meridional transport, are assessed using the North Atlantic Oscillation index. We find that the independent, direct effect of sea ice on the increase of the percentage of Arctic sourced moisture (or Arctic moisture proportion, AMP) is 18.2 ± 4.6% and 10.8 ± 3.6%/100,000 km(2) sea ice lost for each region, respectively, corresponding to increases of 10.9 ± 2.8% and 2.7 ± 1.1%/1 °C of warming in the vapor source regions. The moisture source changes likely result in increases of precipitation and changes in energy balance, creating significant uncertainty for climate predictions.

  10. Observation of Arctic island barren-ground caribou (Rangifer tarandus groenlandicus migratory movement delay due to human induced sea-ice breaking

    Directory of Open Access Journals (Sweden)

    Mathieu Dumond

    2013-06-01

    Full Text Available Normal 0 21 false false false SV X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Normal tabell"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;} The seasonal migration of the Dolphin and Union caribou (Rangifer tarandus groenlandicus herd between Victoria Island and the mainland (Nunavut/Northwest Territories, Canada relies on the formation of sea-ice that connects the Island to the mainland from late-October to early-June.  During an aerial survey of the Dolphin and Union caribou herd in October 2007 on southern Victoria Island, Nunavut, Canada, we documented the short-term effects of the artificial maintenance of an open water channel in the sea-ice on caribou migratory movements during staging along the coast.

  11. Trace element concentrations and gastrointestinal parasites of Arctic terns breeding in the Canadian High Arctic.

    Science.gov (United States)

    Provencher, J F; Braune, B M; Gilchrist, H G; Forbes, M R; Mallory, M L

    2014-04-01

    Baseline data on trace element concentrations are lacking for many species of Arctic marine birds. We measured essential and non-essential element concentrations in Arctic tern (Sterna paradisaea) liver tissue and brain tissue (mercury only) from Canada's High Arctic, and recorded the presence/absence of gastrointestinal parasites during four different phases of the breeding season. Arctic terns from northern Canada had similar trace element concentrations to other seabird species feeding at the same trophic level in the same region. Concentrations of bismuth, selenium, lead and mercury in Arctic terns were high compared to published threshold values for birds. Selenium and mercury concentrations were also higher in Arctic terns from northern Canada than bird species sampled in other Arctic areas. Selenium, mercury and arsenic concentrations varied across the time periods examined, suggesting potential regional differences in the exposure of biota to these elements. For unknown reasons, selenium concentrations were significantly higher in birds with gastrointestinal parasites as compared to those without parasites, while bismuth concentrations were higher in Arctic terns not infected with gastrointestinal parasites.

  12. Forging an Arctic Alliance: Canadian-U.S. JIATF-Arctic

    Science.gov (United States)

    2010-10-27

    Kate. “NSTC to Coordinate Certain Arctic Research Policy Committee Activities,” Office of Science and Technology Policy, 23 August 2010. http...www.whitehouse.gov/blog/2010/08/23/nstc-coordinate-certain-arctic- research - policy -committee-activities (accessed 11 October 2010). NASA. “A Snapshot of

  13. Leading in the Arctic; Translating the United States Arctic Strategy into Opportunities for Peace and Stability

    Science.gov (United States)

    2015-02-16

    Kuersten, Russian Sanctions, China, http://thediplomat.com/2015/01/russian-sanctions- china-and-the-arctic/ 50. Linda Jakobson , China Prepares for an...1975. 32 Jakobson , Linda. China Prepares for an Ice Free Arctic. Stockholm International Peace Institute. March 2010. Kraska, James

  14. Some international perspectives on legislation for the management of human-induced safety risks

    Directory of Open Access Journals (Sweden)

    Alfonso Niemand

    2016-01-01

    Full Text Available Legislation that governs the health and safety of communities near major-hazard installations in South Africa is largely based on existing legislation that had been developed in the United Kingdom and other European Union countries. The latter was developed as a consequence of several major human-induced technological disasters in Europe. The history of the evolution of health-and-safety legislation for the protection of vulnerable communities in European Union (EU countries, France, Malaysia and the USA is explored through a literature survey. A concise comparison is drawn between EU countries, the USA and South Africa to obtain an exploratory view of whether current South-African legislation represents an optimum model for the protection of the health-and-safety of workers and communities near major-hazard installations. The authors come to the conclusion that South-African legislation needs revision as was done in the UK in 2011. Specific areas in the legislation that need revision are an overlap between occupational health and safety and environmental legislation, appropriate land-use planning for the protection of communities near major-hazard installations, the inclusion of vulnerability studies and the refinement of appropriate decision-making instruments such as risk assessment. This article is the first in a series that forms part of a broader study aimed at the development of an optimised model for the regulatory management of human-induced health and safety risks associated with hazardous installations in South Africa.

  15. Incorporating a disturbance observer with direct velocity feedback for control of human-induced vibrations

    Science.gov (United States)

    Nyawako, Donald; Reynolds, Paul; Hudson, Emma

    2016-04-01

    Feedback control strategies are desirable for disturbance rejection of human-induced vibrations in civil engineering structures as human walking forces cannot easily be measured. In relation to human-induced vibration control studies, most past researches have focused on floors and footbridges and the widely used linear controller implemented in the trials has been the direct velocity feedback (DVF) scheme. With appropriate compensation to enhance its robustness, it has been shown to be effective at damping out the problematic modes of vibration of the structures in which the active vibration control systems have been implemented. The work presented here introduces a disturbance observer (DOB) that is used with an outer-loop DVF controller. Results of analytical studies presented in this work based on the dynamic properties of a walkway bridge structure demonstrate the potential of this approach for enhancing the vibration mitigation performance offered by a purely DVF controller. For example, estimates of controlled frequency response functions indicate improved attenuation of vibration around the dominant frequency of the walkway bridge structure as well as at higher resonant frequencies. Controlled responses from three synthesized walking excitation forces on a walkway bridge structure model show that the inclusion of the disturbance observer with an outer loop DVF has potential to improve on the vibration mitigation performance by about 3.5% at resonance and 6-10% off-resonance. These are realised with hard constraints being imposed on the low frequency actuator displacements.

  16. ArcticDEM; A Publically Available, High Resolution Elevation Model of the Arctic

    Science.gov (United States)

    Morin, Paul; Porter, Claire; Cloutier, Michael; Howat, Ian; Noh, Myoung-Jong; Willis, Michael; Bates, Brian; Willamson, Cathleen; Peterman, Kennith

    2016-04-01

    A Digital Elevation Model (DEM) of the Arctic is needed for a large number of reasons, including: measuring and understanding rapid, ongoing changes to the Arctic landscape resulting from climate change and human use and mitigation and adaptation planning for Arctic communities. The topography of the Arctic is more poorly mapped than most other regions of Earth due to logistical costs and the limits of satellite missions with low-latitude inclinations. A convergence of civilian, high-quality sub-meter stereo imagery; petascale computing and open source photogrammetry software has made it possible to produce a complete, very high resolution (2 to 8-meter posting), elevation model of the Arctic. A partnership between the US National Geospatial-intelligence Agency and a team led by the US National Science Foundation funded Polar Geospatial Center is using stereo imagery from DigitalGlobe's Worldview-1, 2 and 3 satellites and the Ohio State University's Surface Extraction with TIN-based Search-space Minimization (SETSM) software running on the University of Illinois's Blue Water supercomputer to address this challenge. The final product will be a seemless, 2-m posting digital surface model mosaic of the entire Arctic above 60 North including all of Alaska, Greenland and Kamchatka. We will also make available the more than 300,000 individual time-stamped DSM strip pairs that were used to assemble the mosaic. The Arctic DEM will have a vertical precision of better than 0.5m and can be used to examine changes in land surfaces such as those caused by permafrost degradation or the evolution of arctic rivers and floodplains. The data set can also be used to highlight changing geomorphology due to Earth surface mass transport processes occurring in active volcanic and glacial environments. When complete the ArcticDEM will catapult the Arctic from the worst to among the best mapped regions on Earth.

  17. Seasonality of global and Arctic black carbon processes in the Arctic Monitoring and Assessment Programme models

    Science.gov (United States)

    Mahmood, Rashed; Salzen, Knut; Flanner, Mark; Sand, Maria; Langner, Joakim; Wang, Hailong; Huang, Lin

    2016-06-01

    This study quantifies black carbon (BC) processes in three global climate models and one chemistry transport model, with focus on the seasonality of BC transport, emissions, wet and dry deposition in the Arctic. In the models, transport of BC to the Arctic from lower latitudes is the major BC source for this region. Arctic emissions are very small. All models simulated a similar annual cycle of BC transport from lower latitudes to the Arctic, with maximum transport occurring in July. Substantial differences were found in simulated BC burdens and vertical distributions, with Canadian Atmospheric Global Climate Model (CanAM) (Norwegian Earth System Model, NorESM) producing the strongest (weakest) seasonal cycle. CanAM also has the shortest annual mean residence time for BC in the Arctic followed by Swedish Meteorological and Hydrological Institute Multiscale Atmospheric Transport and Chemistry model, Community Earth System Model, and NorESM. Overall, considerable differences in wet deposition efficiencies in the models exist and are a leading cause of differences in simulated BC burdens. Results from model sensitivity experiments indicate that convective scavenging outside the Arctic reduces the mean altitude of BC residing in the Arctic, making it more susceptible to scavenging by stratiform (layer) clouds in the Arctic. Consequently, scavenging of BC in convective clouds outside the Arctic acts to substantially increase the overall efficiency of BC wet deposition in the Arctic, which leads to low BC burdens and a more pronounced seasonal cycle compared to simulations without convective BC scavenging. In contrast, the simulated seasonality of BC concentrations in the upper troposphere is only weakly influenced by wet deposition in stratiform clouds, whereas lower tropospheric concentrations are highly sensitive.

  18. Socioeconomic and Cultural Changes in the European Arctic

    NARCIS (Netherlands)

    Stepien, Adam; Banul, Karolina; Scheepstra, Adriana; van Dam, Karin; Latola, Kirsi; Koivurova, Timo; Stepien, Adam; Koivurova, Timo; Kankaanpää, Paula

    2016-01-01

    The chapter provides overview of the Arctic sociocultural landscape, highlighting innovative and growing Arctic cities, thinnig-out rural areas, demographic challenges, and dependence on extractive and primary industries. Indigenous peoples often experience these elements in distinct manners. The EU

  19. A quantitative assessment of Arctic shipping in 2010–2014

    KAUST Repository

    Eguíluz, Victor M.

    2016-08-01

    Rapid loss of sea ice is opening up the Arctic Ocean to shipping, a practice that is forecasted to increase rapidly by 2050 when many models predict that the Arctic Ocean will largely be free of ice toward the end of summer. These forecasts carry considerable uncertainty because Arctic shipping was previously considered too sparse to allow for adequate validation. Here, we provide quantitative evidence that the extent of Arctic shipping in the period 2011–2014 is already significant and that it is concentrated (i) in the Norwegian and Barents Seas, and (ii) predominantly accessed via the Northeast and Northwest Passages. Thick ice along the forecasted direct trans-Arctic route was still present in 2014, preventing transit. Although Arctic shipping remains constrained by the extent of ice coverage, during every September, this coverage is at a minimum, allowing the highest levels of shipping activity. Access to Arctic resources, particularly fisheries, is the most important driver of Arctic shipping thus far.

  20. Hydrochemical Atlas of the Arctic Ocean (NODC Accession 0044630)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The present Hydrochemical Atlas of the Arctic Ocean is a description of hydrochemical conditions in the Arctic Ocean on the basis of a greater body of hydrochemical...

  1. A quantitative assessment of Arctic shipping in 2010-2014.

    Science.gov (United States)

    Eguíluz, Victor M; Fernández-Gracia, Juan; Irigoien, Xabier; Duarte, Carlos M

    2016-08-01

    Rapid loss of sea ice is opening up the Arctic Ocean to shipping, a practice that is forecasted to increase rapidly by 2050 when many models predict that the Arctic Ocean will largely be free of ice toward the end of summer. These forecasts carry considerable uncertainty because Arctic shipping was previously considered too sparse to allow for adequate validation. Here, we provide quantitative evidence that the extent of Arctic shipping in the period 2011-2014 is already significant and that it is concentrated (i) in the Norwegian and Barents Seas, and (ii) predominantly accessed via the Northeast and Northwest Passages. Thick ice along the forecasted direct trans-Arctic route was still present in 2014, preventing transit. Although Arctic shipping remains constrained by the extent of ice coverage, during every September, this coverage is at a minimum, allowing the highest levels of shipping activity. Access to Arctic resources, particularly fisheries, is the most important driver of Arctic shipping thus far.

  2. Pipeline dreams: people, environment, and the Arctic energy frontier

    National Research Council Canada - National Science Library

    Nuttall, Mark

    2010-01-01

    "With a focus on the North American Arctic and sub-Arctic, this book discusses how dreams of extracting resource wealth have been significant in influencing and shaping relations between indigenous...

  3. Arctic shipping emissions inventories and future scenarios

    Directory of Open Access Journals (Sweden)

    J. J. Corbett

    2010-04-01

    Full Text Available The Arctic is a sensitive region in terms of climate change and a rich natural resource for global economic activity. Arctic shipping is an important contributor to the region's anthropogenic air emissions, including black carbon – a short-lived climate forcing pollutant especially effective in accelerating the melting of ice and snow. These emissions are projected to increase as declining sea ice coverage due to climate change allows for increased shipping activity in the Arctic. To understand the impacts of these increased emissions, scientists and modelers require high-resolution, geospatial emissions inventories that can be used for regional assessment modeling. This paper presents 5 km×5 km Arctic emissions inventories of important greenhouse gases, black carbon and other pollutants under existing and future (2050 scenarios that account for growth of shipping in the region, potential diversion traffic through emerging routes, and possible emissions control measures. Short-lived forcing of ~4.5 gigagrams of black carbon from Arctic shipping may increase climate forcing; a first-order calculation of global warming potential due to 2030 emissions in the high-growth scenario suggests that short-lived forcing of ~4.5 gigagrams of black carbon from Arctic shipping may increase climate forcing due to Arctic ships by at least 17% compared to warming from these vessels' CO2 emissions (~42 000 gigagrams. The paper also presents maximum feasible reduction scenarios for black carbon in particular. These emissions reduction scenarios will enable scientists and policymakers to evaluate the efficacy and benefits of technological controls for black carbon, and other pollutants from ships.

  4. How does climate change influence Arctic mercury?

    Science.gov (United States)

    Stern, Gary A; Macdonald, Robie W; Outridge, Peter M; Wilson, Simon; Chételat, John; Cole, Amanda; Hintelmann, Holger; Loseto, Lisa L; Steffen, Alexandra; Wang, Feiyue; Zdanowicz, Christian

    2012-01-01

    Recent studies have shown that climate change is already having significant impacts on many aspects of transport pathways, speciation and cycling of mercury within Arctic ecosystems. For example, the extensive loss of sea-ice in the Arctic Ocean and the concurrent shift from greater proportions of perennial to annual types have been shown to promote changes in primary productivity, shift foodweb structures, alter mercury methylation and demethylation rates, and influence mercury distribution and transport across the ocean-sea-ice-atmosphere interface (bottom-up processes). In addition, changes in animal social behavior associated with changing sea-ice regimes can affect dietary exposure to mercury (top-down processes). In this review, we address these and other possible ramifications of climate variability on mercury cycling, processes and exposure by applying recent literature to the following nine questions; 1) What impact has climate change had on Arctic physical characteristics and processes? 2) How do rising temperatures affect atmospheric mercury chemistry? 3) Will a decrease in sea-ice coverage have an impact on the amount of atmospheric mercury deposited to or emitted from the Arctic Ocean, and if so, how? 4) Does climate affect air-surface mercury flux, and riverine mercury fluxes, in Arctic freshwater and terrestrial systems, and if so, how? 5) How does climate change affect mercury methylation/demethylation in different compartments in the Arctic Ocean and freshwater systems? 6) How will climate change alter the structure and dynamics of freshwater food webs, and thereby affect the bioaccumulation of mercury? 7) How will climate change alter the structure and dynamics of marine food webs, and thereby affect the bioaccumulation of marine mercury? 8) What are the likely mercury emissions from melting glaciers and thawing permafrost under climate change scenarios? and 9) What can be learned from current mass balance inventories of mercury in the Arctic? The

  5. U.S. Government Perspective on Arctic Research

    Science.gov (United States)

    2010-11-01

    Congress and Executive branch • Sets nation’s Arctic research goals and objectives • Develops an integrated national Arctic  research   policy • Helps...to Arctic research,  both basic and applied USARC sets nation’s Arctic research goals USARC: establishes research goals & sets research policy IARPC

  6. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    Science.gov (United States)

    2014-05-15

    emerge in the interior Arctic Ocean, especially over regions where sea ice loss exposes open water. However, this change is not effected by the...htm> Scientific American ("Warming Arctic spurs cyclones and sea ice loss "), < http://www.scientificamerican.com/article/warming- arctic -spurs...cyclones-and-sea- ice - loss /?&WT.mc_id=SA_DD_20140220> Nelson Institute of Environmental Studies at University of Wisconsin feature ("More extreme Arctic

  7. Changing geo-political realities in the Arctic region

    DEFF Research Database (Denmark)

    Sørensen, Camilla T. N.

    2014-01-01

    This article analyzes and discusses how Denmark seeks to manage the changing geopolitical realities in the Arctic region specifically focusing on how Denmark seeks to manage its relations with China in the Arctic region.......This article analyzes and discusses how Denmark seeks to manage the changing geopolitical realities in the Arctic region specifically focusing on how Denmark seeks to manage its relations with China in the Arctic region....

  8. Histone deacetylase inhibitor valproic acid promotes the differentiation of human induced pluripotent stem cells into hepatocyte-like cells.

    Directory of Open Access Journals (Sweden)

    Yuki Kondo

    Full Text Available In this study, we aimed to elucidate the effects and mechanism of action of valproic acid on hepatic differentiation from human induced pluripotent stem cell-derived hepatic progenitor cells. Human induced pluripotent stem cells were differentiated into endodermal cells in the presence of activin A and then into hepatic progenitor cells using dimethyl sulfoxide. Hepatic progenitor cells were matured in the presence of hepatocyte growth factor, oncostatin M, and dexamethasone with valproic acid that was added during the maturation process. After 25 days of differentiation, cells expressed hepatic marker genes and drug-metabolizing enzymes and exhibited drug-metabolizing enzyme activities. These expression levels and activities were increased by treatment with valproic acid, the timing and duration of which were important parameters to promote differentiation from human induced pluripotent stem cell-derived hepatic progenitor cells into hepatocytes. Valproic acid inhibited histone deacetylase activity during differentiation of human induced pluripotent stem cells, and other histone deacetylase inhibitors also enhanced differentiation into hepatocytes. In conclusion, histone deacetylase inhibitors such as valproic acid can be used to promote hepatic differentiation from human induced pluripotent stem cell-derived hepatic progenitor cells.

  9. NATO’s Future Role in the Arctic

    Science.gov (United States)

    2016-05-01

    percent of its natural gas and 75 percent of its oil .14 With a vested economic interest in the region, Russia has developed clear policies , backed by...iv Global Climate Change and Arctic Geopolitics............................. Error! Bookmark not defined. Russian Claims to the Arctic...13 1 Global Climate Change and Arctic Geopolitics Global climate change has a profound

  10. Exploring Arctic Transpolar Drift During Dramatic Sea Ice Retreat

    DEFF Research Database (Denmark)

    Gascard, J.C.; Festy, J.; le Goff, H.

    2008-01-01

    The Arctic is undergoing significant environmental changes due to climate warming. The most evident signal of this warming is the shrinking and thinning of the ice cover of the Arctic Ocean. If the warming continues, as global climate models predict, the Arctic Ocean will change from a perennially...

  11. Establishing Shared Knowledge about Globalization in Asia and the Arctic

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Graczyk, Piotr

    2016-01-01

    We discuss the role of knowledge in relations between Arctic communities and Asia (the Arctic Council observer states: China, India, Japan, Singapore, South Korea). We argue that mutual and shared knowledge between Arctic communities and Asia is necessary for local benefits and comprehensively...

  12. India and the Arctic: environment, economy and politics

    Directory of Open Access Journals (Sweden)

    Tatyana L. Shaumyan

    2016-10-01

    Full Text Available The article analyzes the main trends in the development of India and the development of the Arctic: the participation in the study of global warming and the state of the Arctic ice; the use of the Northern Sea Route for transportation; expansion of international cooperation in the Arctic direction, including with Russia.

  13. Arctic Ocean Paleoceanography and Future IODP Drilling

    Science.gov (United States)

    Stein, Ruediger

    2015-04-01

    Although the Arctic Ocean is a major player in the global climate/earth system, this region is one of the last major physiographic provinces on Earth where the short- and long-term geological history is still poorly known. This lack in knowledge is mainly due to the major technological/logistical problems in operating within the permanently ice-covered Arctic region which makes it difficult to retrieve long and undisturbed sediment cores. Prior to 2004, in the central Arctic Ocean piston and gravity coring was mainly restricted to obtaining near-surface sediments, i.e., only the upper 15 m could be sampled. Thus, all studies were restricted to the late Pliocene/Quaternary time interval, with a few exceptions. These include the four short cores obtained by gravity coring from drifting ice floes over the Alpha Ridge, where older pre-Neogene organic-carbon-rich muds and laminated biosiliceous oozes were sampled. Continuous central Arctic Ocean sedimentary records, allowing a development of chronologic sequences of climate and environmental change through Cenozoic times and a comparison with global climate records, however, were missing prior to the IODP Expedition 302 (Arctic Ocean Coring Expedition - ACEX), the first scientific drilling in the central Arctic Ocean. By studying the unique ACEX sequence, a large number of scientific discoveries that describe previously unknown Arctic paleoenvironments, were obtained during the last decade (for most recent review and references see Stein et al., 2014). While these results from ACEX were unprecedented, key questions related to the climate history of the Arctic Ocean remain unanswered, in part because of poor core recovery, and in part because of the possible presence of a major mid-Cenozoic hiatus or interval of starved sedimentation within the ACEX record. In order to fill this gap in knowledge, international, multidisciplinary expeditions and projects for scientific drilling/coring in the Arctic Ocean are needed. Key

  14. Long-term changes in pigmentation of arctic Daphnia provide potential for reconstructing aquatic UV exposure

    Science.gov (United States)

    Nevalainen, Liisa; Rantala, Marttiina V.; Luoto, Tomi P.; Ojala, Antti E. K.; Rautio, Milla

    2016-07-01

    concurrent with previously recorded major ecological shifts in circumpolar lakes when human induced changes in ecological processes of sensitive arctic ecosystems started to occur. The current centennial record of UV-induced melanisation of sedimentary Daphnia ephippia presents unique reference material for assessing UV impacts in arctic aquatic ecosystems before human influence and during the 20th century climate change and provides potential for assessing past aquatic UV regimes.

  15. Arctic shipping emissions inventories and future scenarios

    Directory of Open Access Journals (Sweden)

    J. J. Corbett

    2010-10-01

    Full Text Available This paper presents 5 km×5 km Arctic emissions inventories of important greenhouse gases, black carbon and other pollutants under existing and future (2050 scenarios that account for growth of shipping in the region, potential diversion traffic through emerging routes, and possible emissions control measures. These high-resolution, geospatial emissions inventories for shipping can be used to evaluate Arctic climate sensitivity to black carbon (a short-lived climate forcing pollutant especially effective in accelerating the melting of ice and snow, aerosols, and gaseous emissions including carbon dioxide. We quantify ship emissions scenarios which are expected to increase as declining sea ice coverage due to climate change allows for increased shipping activity in the Arctic. A first-order calculation of global warming potential due to 2030 emissions in the high-growth scenario suggests that short-lived forcing of ~4.5 gigagrams of black carbon from Arctic shipping may increase global warming potential due to Arctic ships' CO2 emissions (~42 000 gigagrams by some 17% to 78%. The paper also presents maximum feasible reduction scenarios for black carbon in particular. These emissions reduction scenarios will enable scientists and policymakers to evaluate the efficacy and benefits of technological controls for black carbon, and other pollutants from ships.

  16. Arctic Ocean Scientific Drilling: The Next Frontier

    Directory of Open Access Journals (Sweden)

    Ruediger Stein

    2010-04-01

    Full Text Available The modern Arctic Ocean appears to be changing faster than any other region on Earth. To understand the potential extent of high latitude climate change, it is necessary to sample the history stored in the sediments filling the basins and covering the ridges of the Arctic Ocean. These sediments have been imaged with seismic reflection data, but except for the superficial record, which has been piston cored, they have been sampled only on the Lomonosov Ridge in 2004 during the Arctic Coring Expedition (ACEX-IODP Leg 302; Backman et al., 2006 and in 1993 in the ice-free waters in the Fram Strait/Yermak Plateau area (ODP Leg 151; Thiede et al., 1996.Although major progress in Arctic Ocean research has been made during the last few decades, the short- and long-term paleoceanographic and paleoclimatic history as well as its plate-tectonic evolution are poorly known compared to the other oceans. Despite the importance of the Arctic in the climate system, the database we have from this area is still very weak. Large segments of geologic time have not been sampled in sedimentary sections. The question of regional variations cannot be addressed.

  17. Arctic Observing Experiment (AOX) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Rigor, Ignatius [Applied Physics Lab, University of Washington; Johnson, Jim [Applied Physics Lab, University of Washington; Motz, Emily [National Ice Center; Bisic, Aaron [National Ice Center

    2017-06-30

    Our ability to understand and predict weather and climate requires an accurate observing network. One of the pillars of this network is the observation of the fundamental meteorological parameters: temperature, air pressure, and wind. We plan to assess our ability to measure these parameters for the polar regions during the Arctic Observing Experiment (AOX, Figure 1) to support the International Arctic Buoy Programme (IABP), Arctic Observing Network (AON), International Program for Antarctic Buoys (IPAB), and Southern Ocean Observing System (SOOS). Accurate temperature measurements are also necessary to validate and improve satellite measurements of surface temperature across the Arctic. Support for research associated with the campaign is provided by the National Science Foundation, and by other US agencies contributing to the US Interagency Arctic Buoy Program. In addition to the support provided by the U.S Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s North Slope of Alaska (NSA) site at Barrow and the National Science Foundation (NSF), the U.S. IABP is supported by the U.S. Coast Guard (USCG), the National Aeronautics and Space Administration (NASA), the National Ice Center (NIC), the National Oceanic and Atmospheric Administration (NOAA), and the Office of Naval Research (ONR).

  18. Chlorinated hydrocarbon contaminants in arctic marine mammals.

    Science.gov (United States)

    Norstrom, R J; Muir, D C

    1994-09-16

    By 1976, the presence of chlorinated hydrocarbon contaminants (CHCs) had been demonstrated in fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), hooded seal (Cystophora cristata), bearded seal (Erignathus barbatus), walrus (Obdobenus rosmarus divergens), beluga (Delphinapterus leucas), porpoise (Phocoena phocoena) and polar bear (Ursus maritimus) in various parts of the Arctic. In spite of this early interest, very little subsequent research on contaminants in Arctic marine mammals was undertaken until the mid-1980s. Since that time, there has been an explosion of interest, resulting in a much expanded data base on contaminants in Arctic marine mammals. Except in the Russian Arctic, data have now been obtained on the temporospatial distribution of PCBs and other contaminants in ringed seal, beluga and polar bear. Contaminants in narwhal (Monodon monoceros) have also now been measured. On a fat weight basis, the sum of DDT-related compounds (S-DDT) and PCB levels are lowest in walrus (St. Lawrence and ringed seal in the Baltic Sea, indicate that overall contamination of the Arctic marine ecosystem is 10-50 times less than the most highly contaminated areas in the northern hemisphere temperate latitude marine environment. Geographic distribution of residue levels in polar bears indicates a gradual increase from Alaska east to Svalbard, except PCB levels are significantly higher in eastern Greenland and Svalbard. Information on temporal trends is somewhat contradictory.(ABSTRACT TRUNCATED AT 400 WORDS)

  19. 2nd International Arctic Ungulate Conference

    Directory of Open Access Journals (Sweden)

    A. Anonymous

    1996-01-01

    Full Text Available The 2nd International Arctic Ungulate Conference was held 13-17 August 1995 on the University of Alaska Fairbanks campus. The Institute of Arctic Biology and the Alaska Cooperative Fish and Wildlife Research Unit were responsible for organizing the conference with assistance from biologists with state and federal agencies and commercial organizations. David R. Klein was chair of the conference organizing committee. Over 200 people attended the conference, coming from 10 different countries. The United States, Canada, and Norway had the largest representation. The conference included invited lectures; panel discussions, and about 125 contributed papers. There were five technical sessions on Physiology and Body Condition; Habitat Relationships; Population Dynamics and Management; Behavior, Genetics and Evolution; and Reindeer and Muskox Husbandry. Three panel sessions discussed Comparative caribou management strategies; Management of introduced, reestablished, and expanding muskox populations; and Health risks in translocation of arctic ungulates. Invited lectures focused on the physiology and population dynamics of arctic ungulates; contaminants in food chains of arctic ungulates and lessons learned from the Chernobyl accident; and ecosystem level relationships of the Porcupine Caribou Herd.

  20. The Arctic and Polar cells act on the Arctic sea ice variation

    Directory of Open Access Journals (Sweden)

    Weihong Qian

    2015-08-01

    Full Text Available The Arctic sea ice has undergone a substantial long-term decline with superimposed interannual sea ice minimum (SIM events over the last decades. This study focuses on the relationship between atmospheric circulation and the SIM events in the Arctic region. Four reanalysis products and simulations of one climate model are first analysed to confirm the existence of the Arctic cell, a meridional circulation cell to the north of 80°N, by visualising through the mean streamline and mean mass stream function in the Northern Hemisphere. Dynamical analyses of zonally averaged stationary eddy heat and momentum fluxes as well as the global precipitation rate data further confirm its existence. Finally, we found that the change in the Arctic sea ice concentration lags the variations of the descending air flow intensity associated with the Polar and Arctic cells, by about 2 months for the climatic annual cycle and about 10 months for the interannual anomaly. Five Arctic SIM events during the last three decades support this relationship. These results have implications for understanding the relationship between atmospheric circulation and sea-ice variations, and for predicting the Arctic sea ice changes.

  1. Consequences of future increased Arctic runoff on Arctic Ocean stratification, circulation, and sea ice cover

    Science.gov (United States)

    Nummelin, Aleksi; Ilicak, Mehmet; Li, Camille; Smedsrud, Lars H.

    2016-01-01

    The Arctic Ocean has important freshwater sources including river runoff, low evaporation, and exchange with the Pacific Ocean. In the future, we expect even larger freshwater input as the global hydrological cycle accelerates, increasing high-latitude precipitation, and river runoff. Previous modeling studies show some robust responses to high-latitude freshwater perturbations, including a strengthening of Arctic stratification and a weakening of the large-scale ocean circulation; some idealized modeling studies also document a stronger cyclonic circulation within the Arctic Ocean itself. With the broad range of scales and processes involved, the overall effect of increasing runoff requires an understanding of both the local processes and the broader linkages between the Arctic and surrounding oceans. Here we adopt a more comprehensive modeling approach by increasing river runoff to the Arctic Ocean in a coupled ice-ocean general circulation model, and show contrasting responses in the polar and subpolar regions. Within the Arctic, the stratification strengthens, the halocline and Atlantic Water layer warm, and the cyclonic circulation spins up, in agreement with previous work. In the subpolar North Atlantic, the model simulates a colder and fresher water column with weaker barotropic circulation. In contrast to the estuarine circulation theory, the volume exchange between the Arctic Ocean and the surrounding oceans does not increase with increasing runoff. While these results are robust in our model, we require experiments with other model systems and more complete observational syntheses to better constrain the sensitivity of the climate system to high-latitude freshwater perturbations.

  2. Arctic in Rapid Transition: Priorities for the future of marine and coastal research in the Arctic

    Science.gov (United States)

    Werner, Kirstin; Fritz, Michael; Morata, Nathalie; Keil, Kathrin; Pavlov, Alexey; Peeken, Ilka; Nikolopoulos, Anna; Findlay, Helen S.; Kędra, Monika; Majaneva, Sanna; Renner, Angelika; Hendricks, Stefan; Jacquot, Mathilde; Nicolaus, Marcel; O'Regan, Matt; Sampei, Makoto; Wegner, Carolyn

    2016-09-01

    Understanding and responding to the rapidly occurring environmental changes in the Arctic over the past few decades require new approaches in science. This includes improved collaborations within the scientific community but also enhanced dialogue between scientists and societal stakeholders, especially with Arctic communities. As a contribution to the Third International Conference on Arctic Research Planning (ICARPIII), the Arctic in Rapid Transition (ART) network held an international workshop in France, in October 2014, in order to discuss high-priority requirements for future Arctic marine and coastal research from an early-career scientists (ECS) perspective. The discussion encompassed a variety of research fields, including topics of oceanographic conditions, sea-ice monitoring, marine biodiversity, land-ocean interactions, and geological reconstructions, as well as law and governance issues. Participants of the workshop strongly agreed on the need to enhance interdisciplinarity in order to collect comprehensive knowledge about the modern and past Arctic Ocean's geo-ecological dynamics. Such knowledge enables improved predictions of Arctic developments and provides the basis for elaborate decision-making on future actions under plausible environmental and climate scenarios in the high northern latitudes. Priority research sheets resulting from the workshop's discussions were distributed during the ICARPIII meetings in April 2015 in Japan, and are publicly available online.

  3. Arctic megaslide at presumed rest

    Science.gov (United States)

    Geissler, Wolfram H.; Gebhardt, A. Catalina; Gross, Felix; Wollenburg, Jutta; Jensen, Laura; Schmidt-Aursch, Mechita C.; Krastel, Sebastian; Elger, Judith; Osti, Giacomo

    2016-12-01

    Slope failure like in the Hinlopen/Yermak Megaslide is one of the major geohazards in a changing Arctic environment. We analysed hydroacoustic and 2D high-resolution seismic data from the apparently intact continental slope immediately north of the Hinlopen/Yermak Megaslide for signs of past and future instabilities. Our new bathymetry and seismic data show clear evidence for incipient slope instability. Minor slide deposits and an internally-deformed sedimentary layer near the base of the gas hydrate stability zone imply an incomplete failure event, most probably about 30000 years ago, contemporaneous to or shortly after the Hinlopen/Yermak Megaslide. An active gas reservoir at the base of the gas hydrate stability zone demonstrate that over-pressured fluids might have played a key role in the initiation of slope failure at the studied slope, but more importantly also for the giant HYM slope failure. To date, it is not clear, if the studied slope is fully preconditioned to fail completely in future or if it might be slowly deforming and creeping at present. We detected widespread methane seepage on the adjacent shallow shelf areas not sealed by gas hydrates.

  4. Arctic Infrastructures: Tele Field Notes

    Directory of Open Access Journals (Sweden)

    Rafico Ruiz

    2014-09-01

    Full Text Available This article contextualizes the conditions of rural “connectivity” in the Canadian Arctic. It examines the emergence of satellites, fibre optic cables, and intranets as modes of social infrastructure at the outset of the twenty-first century. At present, Nunavut, the Northwest Territories, and the Yukon are all at a complicated confluence in that their current and inadequate telecommunications infrastructures are in the process of being renegotiated, re-designed, and re-allotted across civic, governmental, and corporate interests. The article shows how it is at sites of friction that the overlapping if fading legacies of systems-based thinking are emerging: satellites orbiting over fibre optic cable lines; corporate actors competing rather than coordinating with government agencies; and neoliberal rationales of mapping, division, and speed creating disjointed local markets. More broadly, these sites also demonstrate how indigenous forms of “connection” across the globe are increasingly experiencing telecommunications’ lags and temporal disjunctures that are having very material effects on their supposedly post-colonial lives.

  5. Interaction of Salmonella enterica Serovar Typhimurium with Intestinal Organoids Derived from Human Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Forbester, Jessica L; Goulding, David; Vallier, Ludovic; Hannan, Nicholas; Hale, Christine; Pickard, Derek; Mukhopadhyay, Subhankar; Dougan, Gordon

    2015-07-01

    The intestinal mucosa forms the first line of defense against infections mediated by enteric pathogens such as salmonellae. Here we exploited intestinal "organoids" (iHOs) generated from human induced pluripotent stem cells (hIPSCs) to explore the interaction of Salmonella enterica serovar Typhimurium with iHOs. Imaging and RNA sequencing were used to analyze these interactions, and clear changes in transcriptional signatures were detected, including altered patterns of cytokine expression after the exposure of iHOs to bacteria. S. Typhimurium microinjected into the lumen of iHOs was able to invade the epithelial barrier, with many bacteria residing within Salmonella-containing vacuoles. An S. Typhimurium invA mutant defective in the Salmonella pathogenicity island 1 invasion apparatus was less capable of invading the iHO epithelium. Hence, we provide evidence that hIPSC-derived organoids are a promising model of the intestinal epithelium for assessing interactions with enteric pathogens.

  6. Cardiomyopathy in a dish: using human inducible pluripotent stem cells to model inherited cardiomyopathies.

    Science.gov (United States)

    Kamdar, Forum; Klaassen Kamdar, Andre; Koyano-Nakagawa, Naoko; Garry, Mary G; Garry, Daniel J

    2015-09-01

    Inherited cardiomyopathies, including hypertrophic cardiomyopathy, dilated cardiomyopathies, arrythmogenic right ventricular cardiomyopathy, and other inherited forms of heart failure, represent a unique set of genetically defined cardiovascular disease processes. Unraveling the molecular mechanisms of these deadly forms of human heart disease has been challenging, but recent groundbreaking scientific advances in stem cell technology have allowed for the generation of patient-specific human inducible stem cell (hiPSC)-derived cardiomyocytes (CMs). hiPSC-derived CMs retain the genetic blueprint of the patient, they can be maintained in culture, and they recapitulate the phenotypic characteristics of the disease in vitro, thus serving as a disease in a dish. This review provides an overview of in vitro modeling of inherited cardiomyopathies with the use of patient-specific hiPSC-derived CMs. Copyright © 2015. Published by Elsevier Inc.

  7. Alzheimer's disease modeling: ups, downs, and perspectives for human induced pluripotent stem cells.

    Science.gov (United States)

    Wojda, Urszula; Kuznicki, Jacek

    2013-01-01

    Major breakthroughs are required to win the war against the increasing threat of Alzheimer's disease. Until now, however, despite enormous efforts and funds, effective therapies are lacking, and adequate models for drug validation are still unavailable. In this article, we review the available animal and cellular models of different features of human Alzheimer's disease and critically evaluate their usefulness for understanding the mechanisms of the disease. The majority of the presently used models are based on the amyloid-β and hyperphosphorylated tau hypothesis, which resembles features of familial Alzheimer's disease. Unfortunately, these models offer limited help for understanding the pathomechanisms of the early stages of sporadic Alzheimer's disease. Thus, new models are needed to discover ways to treat or delay the onset of Alzheimer's disease, and we discuss the prospects for such desperately needed models, including human induced pluripotent stem cells and in silico brain models.

  8. Generation of human induced pluripotent stem cells using genome integrating or non-integrating methods.

    Science.gov (United States)

    Šimara, P; Tesařová, L; Padourová, S; Koutná, I

    2014-01-01

    Preclinical studies have demonstrated the promising potential of human induced pluripotent stem cells (hiPSCs) for clinical application. To fulfil this goal, efficient and safe methods to generate them must be established. Various reprogramming techniques were presented during seven years of hiPSCs research. Genome non-integrating and completely xeno-free protocols from the first biopsy to stable hiPSC clones are highly preferable in terms of future clinical application. In this short communication, we summarize the reprogramming experiments performed in our laboratories. We successfully generated hiPSCs using STEMCCA lentivirus, Sendai virus or episomal vectors. Human neonatal fibroblasts and CD34(+) blood progenitors were used as cell sources and were maintained either on mouse embryonic feeder cells or in feeder-free conditions. The reprogramming efficiency was comparable for all three methods and both cell types, while the best results were obtained in feeder-free conditions.

  9. Human induced pluripotent stem cells: A new source for brown and white adipocytes

    Institute of Scientific and Technical Information of China (English)

    Anne-Laure; Hafner; Christian; Dani

    2014-01-01

    Mesenchymal stem cells(MSCs) derived from human induced pluripotent stem cells(hiPSCs) provide a novel source for generating adipocytes, thus opening new avenues for fundamental research and clinical medicine. We present the adipogenic potential of hiPSCs and the various methods to derive hiPSC-MSCs. We discuss the main characteristic of hiPSC-MSCs, which is their low adipogenic capacity as compared to adult-MSCs. Finally, we propose several hypotheses to explanation this feature, underlying a potential critical role of the micro-environment. We favour the hypothesis that the range of factors or culture conditions required to induce adipocyte differentiation of MSCs derived from adult tissues and from embryonic-like cells could differ.

  10. Establishment of Human Neural Progenitor Cells from Human Induced Pluripotent Stem Cells with Diverse Tissue Origins

    Directory of Open Access Journals (Sweden)

    Hayato Fukusumi

    2016-01-01

    Full Text Available Human neural progenitor cells (hNPCs have previously been generated from limited numbers of human induced pluripotent stem cell (hiPSC clones. Here, 21 hiPSC clones derived from human dermal fibroblasts, cord blood cells, and peripheral blood mononuclear cells were differentiated using two neural induction methods, an embryoid body (EB formation-based method and an EB formation method using dual SMAD inhibitors (dSMADi. Our results showed that expandable hNPCs could be generated from hiPSC clones with diverse somatic tissue origins. The established hNPCs exhibited a mid/hindbrain-type neural identity and uniform expression of neural progenitor genes.

  11. AROME-Arctic: New operational NWP model for the Arctic region

    Science.gov (United States)

    Süld, Jakob; Dale, Knut S.; Myrland, Espen; Batrak, Yurii; Homleid, Mariken; Valkonen, Teresa; Seierstad, Ivar A.; Randriamampianina, Roger

    2016-04-01

    In the frame of the EU-funded project ACCESS (Arctic Climate Change, Economy and Society), MET Norway aimed 1) to describe the present monitoring and forecasting capabilities in the Arctic; and 2) to identify the key factors limiting the forecasting capabilities and to give recommendations on key areas to improve the forecasting capabilities in the Arctic. We have observed that the NWP forecast quality is lower in the Arctic than in the regions further south. Earlier research indicated that one of the factors behind this is the composition of the observing system in the Arctic, in particular the scarceness of conventional observations. To further assess possible strategies for alleviating the situation and propose scenarios for a future Arctic observing system, we have performed a set of experiments to gain a more detailed insight in the contribution of the components of the present observing system in a regional state-of-the-art non-hydrostatic NWP model using the AROME physics (Seity et al, 2011) at 2.5 km horizontal resolution - AROME-Arctic. Our observing system experiment studies showed that conventional observations (Synop, Buoys) can play an important role in correcting the surface state of the model, but prove that the present upper-air conventional (Radiosondes, Aircraft) observations in the area are too scarce to have a significant effect on forecasts. We demonstrate that satellite sounding data play an important role in improving forecast quality. This is the case with satellite temperature sounding data (AMSU-A, IASI), as well as with the satellite moisture sounding data (AMSU-B/MHS, IASI). With these sets of observations, the AROME-Arctic clearly performs better in forecasting extreme events, like for example polar lows. For more details see presentation by Randriamampianina et al. in this session. The encouraging performance of AROME-Arctic lead us to implement it with more observations and improved settings into daily runs with the objective to

  12. Roles of CDX2 and EOMES in human induced trophoblast progenitor cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying, E-mail: ying.chen@hc.msu.edu [Department of Obstetrics, Gynecology and Reproductive Biology, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503 (United States); Wang, Kai [Department of Obstetrics, Gynecology and Reproductive Biology, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503 (United States); Gong, Yun Guo; Khoo, Sok Kean [Genomic Microarray Core Facility, Van Andel Research Institute, Grand Rapids, MI 49503 (United States); Leach, Richard, E-mail: Richard.Leach@hc.msu.edu [Department of Obstetrics, Gynecology and Reproductive Biology, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503 (United States); Department of Obstetrics, Gynecology and Women’s Health, Spectrum Health Medical Group, Grand Rapids, MI 49503 (United States)

    2013-02-08

    Highlights: ► CDX2 and EOMES play critical roles in human induced trophoblast progenitors (iTP). ► iTP cells directly transformed from fibroblasts. ► Differentiation of iTP cells into extravillous trophoblasts and syncytiotrophoblasts. -- Abstract: Abnormal trophoblast lineage proliferation and differentiation in early pregnancy have been associated with the pathogenesis of placenta diseases of pregnancy. However, there is still a gap in understanding the molecular mechanisms of early placental development due to the limited primary trophoblast cultures and fidelity of immortalized trophoblast lines. Trophoblasts stem (TS) cells, an in vitro model of trophectoderm that can differentiate into syncytiotrophoblasts and extravillous trophoblasts, can be an attractive tool for early pregnancy research. TS cells are well established in mouse but not in humans due to insufficient knowledge of which trophoblast lineage-specific transcription factors are involved in human trophectoderm (TE) proliferation and differentiation. Here, we applied induced pluripotent stem cell technique to investigate the human trophoblast lineage-specific transcription factors. We established human induced trophoblast progenitor (iTP) cells by direct reprogramming the fibroblasts with a pool of mouse trophoblast lineage-specific transcription factors consisting of CDX2, EOMES, and ELF5. The human iTP cells exhibit epithelial morphology and can be maintained in vitro for more than 2 months. Gene expression profile of these cells was tightly clustered with human trophectoderm but not with human neuron progenitor cells, mesenchymal stem cells, or endoderm cells. These cells are capable of differentiating into cells with an invasive capacity, suggesting extravillous trophoblasts. They also form multi-nucleated cells which secrete human chorionic gonadotropin and estradiol, consistent with a syncytiotrophoblast phenotype. Our results provide the evidence that transcription factors CDX2 and

  13. Identification and characterization of calcium sparks in cardiomyocytes derived from human induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Guang Qin Zhang

    Full Text Available INTRODUCTION: Ca2+ spark constitutes the elementary units of cardiac excitation-contraction (E-C coupling in mature cardiomyocytes. Human induced pluripotent stem cell (hiPSC-derived cardiomyocytes are known to have electrophysiological properties similar to mature adult cardiomyocytes. However, it is unclear if they share similar calcium handling property. We hypothesized that Ca2+ sparks in human induced pluripotent stem cell (hiPSCs-derived cardiomyocytes (hiPSC-CMs may display unique structural and functional properties than mature adult cardiomyocytes. METHODS AND RESULTS: Ca2+ sparks in hiPSC-CMs were recorded with Ca2+ imaging assay with confocal laser scanning microscopy. Those sparks were stochastic with a tendency of repetitive occurrence at the same site. Nevertheless, the spatial-temporal properties of Ca2+ spark were analogous to that of adult CMs. Inhibition of L-type Ca2+ channels by nifedipine caused a 61% reduction in calcium spark frequency without affecting amplitude of those sparks and magnitude of caffeine releasable sarcoplasmic reticulum (SR Ca2+ content. In contrast, high extracellular Ca2+ and ryanodine increased the frequency, full width at half maximum (FWHM and full duration at half maximum (FDHM of spontaneous Ca2+ sparks. CONCLUSIONS: For the first time, spontaneous Ca2+ sparks were detected in hiPSC-CMs. The Ca2+ sparks are predominately triggered by L-type Ca2+ channels mediated Ca2+ influx, which is comparable to sparks detected in adult ventricular myocytes in which cardiac E-C coupling was governed by a Ca2+-induced Ca2+ release (CICR mechanism. However, focal repetitive sparks originated from the same intracellular organelle could reflect an immature status of the hiPSC-CMs.

  14. Light-absorbing impurities in Arctic snow

    Directory of Open Access Journals (Sweden)

    S. J. Doherty

    2010-08-01

    Full Text Available Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its content of light-absorbing impurities, expanding and updating the 1983–1984 survey of Clarke and Noone. Samples were collected in Alaska, Canada, Greenland, Svalbard, Norway, Russia, and the Arctic Ocean during 2005–2009, on tundra, glaciers, ice caps, sea ice, frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack is accessible for sampling. Sampling was carried out in summer on the Greenland ice sheet and on the Arctic Ocean, of melting glacier snow and sea ice as well as cold snow. About 1200 snow samples have been analyzed for this study.

    The snow is melted and filtered; the filters are analyzed in a specially designed spectrophotometer system to infer the concentration of black carbon (BC, the fraction of absorption due to non-BC light-absorbing constituents and the absorption Ångstrom exponent of all particles. The reduction of snow albedo is primarily due to BC, but other impurities, principally brown (organic carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. The meltwater from selected snow samples was saved for chemical analysis to identify sources of the impurities. Median BC amounts in surface snow are as follows (nanograms of carbon per gram of snow: Greenland 3, Arctic Ocean snow 7, melting sea ice 8, Arctic Canada 8, Subarctic Canada 14, Svalbard 13, Northern Norway 21, Western Arctic Russia 26, Northeastern Siberia 17. Concentrations are more variable in the European Arctic than in Arctic Canada or the Arctic Ocean, probably because of the proximity

  15. Carbon dioxide exchange in the Arctic

    DEFF Research Database (Denmark)

    Ravn, Nynne Marie Rand

    temperature increased ER in the short-term at the low arctic heath and the δ13C value derived from ER were increased indicating emission of old soil C in response to summer warming. A long lasting response of ER to warming was also evident at the subarctic heaths and after as long as 22 years of summer...... in further warming. This PhD thesis addresses different aspects of climate change effects on C dynamics in the Arctic. The focus has been on i) changes in ER, age of the C sources, GEP and the net ecosystem exchange (NEE) in response to long- and short-term climate manipulations and ii) comparisons of CO2...... fluxes and organic nutrient utilization between ecosystems occurring from different latitudes and dominated by different vegetation types. These aspects are important to understand the effects of climate change on the CO2 balance in the Arctic and its potential positive feedback on global climate change...

  16. Predictability of the Arctic sea ice edge

    Science.gov (United States)

    Goessling, H. F.; Tietsche, S.; Day, J. J.; Hawkins, E.; Jung, T.

    2016-02-01

    Skillful sea ice forecasts from days to years ahead are becoming increasingly important for the operation and planning of human activities in the Arctic. Here we analyze the potential predictability of the Arctic sea ice edge in six climate models. We introduce the integrated ice-edge error (IIEE), a user-relevant verification metric defined as the area where the forecast and the "truth" disagree on the ice concentration being above or below 15%. The IIEE lends itself to decomposition into an absolute extent error, corresponding to the common sea ice extent error, and a misplacement error. We find that the often-neglected misplacement error makes up more than half of the climatological IIEE. In idealized forecast ensembles initialized on 1 July, the IIEE grows faster than the absolute extent error. This means that the Arctic sea ice edge is less predictable than sea ice extent, particularly in September, with implications for the potential skill of end-user relevant forecasts.

  17. Arctic Ozone Depletion from UARS MLS Measurements

    Science.gov (United States)

    Manney, G. L.

    1995-01-01

    Microwave Limb Sounder (MLS) measurements of ozone during four Arctic winters are compared. The evolution of ozone in the lower stratosphere is related to temperature, chlorine monoxide (also measured by MLS), and the evolution of the polar vortex. Lagrangian transport calculations using winds from the United Kingdom Meteorological Office's Stratosphere-Troposphere Data Assimilation system are used to estimate to what extent the evolution of lower stratospheric ozone is controlled by dynamics. Observations, along with calculations of the expected dynamical behavior, show evidence for chemical ozone depletion throughout most of the Arctic lower stratospheric vortex during the 1992-93 middle and late winter, and during all of the 1994-95 winter that was observed by MLS. Both of these winters were unusually cold and had unusually cold and had unusually strong Arctic polar vortices compared to meteorological data over the past 17 years.

  18. Fate of mercury in the Arctic (FOMA)

    DEFF Research Database (Denmark)

    Skov, H.; Christensen, J.; Asmund, G.

    This report is the final reporting of the project FONA, funded by the Danish Environmental Protection Agency with means from the MIKA/DANCEA funds for Environmental Support to the Arctic Region. The aim of the project is to study the intercompartment mercury transport chain in the arctic area. From...... atmospheric deposition of mercury on sea surfaces to uptake in marine organisms, bio-accumulation, and finally mercury levels in mammals. The studies in the project are focused on the behaviour of mercury during the spring period where special phenomena lead to an enhanced deposition of mercury in the Arctic...... environment, at a time where the marine ecosystem is particularly active. The studies also include a comprehensive time trend study of mercury in top carnivore species. Each of these studies contributes towards establishing the knowledge necessary to develop a general model for transport and uptake of mercury...

  19. Quantum imaging for underwater arctic navigation

    Science.gov (United States)

    Lanzagorta, Marco

    2017-05-01

    The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.

  20. Politics of sustainability in the Arctic

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram; Jacobsen, Uffe; Strandsbjerg, Jeppe

    2017-01-01

    The concept of sustainability has taken centre stage in Arctic politics. However, there is little agreement on what ‘sustainable’ means. For different actors (governments, indigenous people, NGOs, etc.) the concept implies different sets of opportunities and precautions. Sustainability, therefore......, is much more a fundamental idea to be further elaborated depending on contexts than a definable term with a specific meaning. The paper argues a research agenda that aims to map and analyse the role of sustainability in political and economic strategies in the Arctic. Sustainability has become...... a fundamental concept that orders the relationship between the environment (nature) and development (economy), however, in the process rearticulating other concepts such as identity (society) and security (state). Hence, we discuss, first, how sustainability when meeting the Arctic changes its meaning...

  1. Parasitism in bivalves from an Arctic ecosystem

    Science.gov (United States)

    Petersen, G. Høpner

    1984-03-01

    In arctic ecosystems parasitism seems less conspicuous than in more diverse tropical ecosystems. However, several host-parasite relations may be a burden in Arctic ecosystems and modify energy-flow patterns. Four different localities of the shallow shelf off Godhavn, West Greenland, were studied with regard to biomass, production and life cycles of selected bivalve and polychaete species. The following important parasite-bivalve associations were found: the athecate hydroid Monobrachium parasitum on Macoma calcarea; the digenetic trematode Gymnophallus somateriae in Hiatella byssifera; an unidentified species of turbellarian in Hiatella byssifera; and the nemertean Malacobdella grossa in Mya truncata. In the bivalves Mytilus edulis, Serripes groenlandicus and Cardium ciliatum only few parasites were detected. Parasitism seems to follow the general trend observed in Arctic ecosystems which exhibit low species diversities and high numbers of individuals.

  2. Fate of mercury in the Arctic (FOMA)

    DEFF Research Database (Denmark)

    Skov, H.; Christensen, J.; Asmund, G.

    This report is the final reporting of the project FONA, funded by the Danish Environmental Protection Agency with means from the MIKA/DANCEA funds for Environmental Support to the Arctic Region. The aim of the project is to study the intercompartment mercury transport chain in the arctic area. From...... atmospheric deposition of mercury on sea surfaces to uptake in marine organisms, bio-accumulation, and finally mercury levels in mammals. The studies in the project are focused on the behaviour of mercury during the spring period where special phenomena lead to an enhanced deposition of mercury in the Arctic...... environment, at a time where the marine ecosystem is particularly active. The studies also include a comprehensive time trend study of mercury in top carnivore species. Each of these studies contributes towards establishing the knowledge necessary to develop a general model for transport and uptake of mercury...

  3. Mean Dynamic Topography of the Arctic Ocean

    Science.gov (United States)

    Farrell, Sinead Louise; Mcadoo, David C.; Laxon, Seymour W.; Zwally, H. Jay; Yi, Donghui; Ridout, Andy; Giles, Katherine

    2012-01-01

    ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along-track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high-resolution ICEn MSS. Second, we estimate the 5.5-year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite-only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller-scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.

  4. Role of Greenland meltwater in the changing Arctic

    Science.gov (United States)

    Dukhovskoy, Dmitry; Proshutinsky, Andrey; Timmermans, Mary-Louise; Myers, Paul; Platov, Gennady; Bamber, Jonathan; Curry, Beth; Somavilla, Raquel

    2016-04-01

    Observational data show that the Arctic ocean-ice-atmosphere system has been changing over the last two decades. Arctic change is manifest in the atypical behavior of the climate indices in the 21st century. Before the 2000s, these indices characterized the quasi-decadal variability of the Arctic climate related to different circulation regimes. Between 1948 and 1996, the Arctic atmospheric circulation alternated between anticyclonic circulation regimes and cyclonic circulation regimes with a period of 10-15 years. Since 1997, however, the Arctic has been dominated by an anticyclonic regime. Previous studies indicate that in the 20th century, freshwater and heat exchange between the Arctic Ocean and the sub-Arctic seas were self-regulated and their interactions were realized via quasi-decadal climate oscillations. What physical processes in the Arctic Ocean - sub-Arctic ocean-ice-atmosphere system are responsible for the observed changes in Arctic climate variability? The presented work is motivated by our hypothesis that in the 21st century, these quasi-decadal oscillations have been interrupted as a result of an additional freshwater source associated with Greenland Ice Sheet melt. Accelerating since the early 1990s, the Greenland Ice Sheet mass loss exerts a significant impact on thermohaline processes in the sub-Arctic seas. Surplus Greenland freshwater, the amount of which is about a third of the freshwater volume fluxed into the region during the 1970s Great Salinity Anomaly event, can spread and accumulate in the sub-Arctic seas influencing convective processes there. It is not clear, however, whether Greenland freshwater can propagate into the interior convective regions in the Labrador Sea and the Nordic Seas. In order to investigate the fate and pathways of Greenland freshwater in the sub-Arctic seas and to determine how and at what rate Greenland freshwater propagates into the convective regions, several numerical experiments using a passive tracer to

  5. Benthic primary production and mineralization in a High Arctic Fjord

    DEFF Research Database (Denmark)

    Attard, Karl M.; Hancke, Kasper; Sejr, Mikael K.

    2016-01-01

    Coastal and shelf systems likely exert major influence on Arctic Ocean functioning, yet key ecosystem processes remain poorly quantified. We employed the aquatic eddy covariance (AEC) oxygen (O2) flux method to estimate benthic primary production and mineralization in a High Arctic Greenland fjord...... light data, we estimate an annual Arctic Ocean benthic GPP of 11.5 × 107 t C yr−1. On average, this value represents 26% of the Arctic Ocean annual net phytoplankton production estimates. This scarcely considered component is thus potentially important for contemporary and future Arctic ecosystem...

  6. Climate change and the ecology and evolution of Arctic vertebrates

    DEFF Research Database (Denmark)

    Gilg, Olivier; Kovacs, Kit M.; Aars, J.

    2012-01-01

    Climate change is taking place more rapidly and severely in the Arctic than anywhere on the globe, exposing Arctic vertebrates to a host of impacts. Changes in the cryosphere dominate the physical changes that already affect these animals, but increasing air temperatures, changes in precipitation......, and ocean acidification will also affect Arctic ecosystems in the future. Adaptation via natural selection is problematic in such a rapidly changing environment. Adjustment via phenotypic plasticity is therefore likely to dominate Arctic vertebrate responses in the short term, and many such adjustments have...... immigration from the South, many Arctic vertebrates are expected to become increasingly threatened during this century....

  7. Climate of the Arctic marine environment.

    Science.gov (United States)

    Walsh, John E

    2008-03-01

    The climate of the Arctic marine environment is characterized by strong seasonality in the incoming solar radiation and by tremendous spatial variations arising from a variety of surface types, including open ocean, sea ice, large islands, and proximity to major landmasses. Interannual and decadal-scale variations are prominent features of Arctic climate, complicating the distinction between natural and anthropogenically driven variations. Nevertheless, climate models consistently indicate that the Arctic is the most climatically sensitive region of the Northern Hemisphere, especially near the sea ice margins. The Arctic marine environment has shown changes over the past several decades, and these changes are part of a broader global warming that exceeds the range of natural variability over the past 1000 years. Record minima of sea ice coverage during the past few summers and increased melt from Greenland have important implications for the hydrographic regime of the Arctic marine environment. The recent changes in the atmosphere (temperature, precipitation, pressure), sea ice, and ocean appear to be a coordinated response to systematic variations of the large-scale atmospheric circulation, superimposed on a general warming that is likely associated with increasing greenhouse gases. The changes have been sufficiently large in some sectors (e.g., the Bering/Chukchi Seas) that consequences for marine ecosystems appear to be underway. Global climate models indicate an additional warming of several degrees Celsius in much of the Arctic marine environment by 2050. However, the warming is seasonal (largest in autumn and winter), spatially variable, and closely associated with further retreat of sea ice. Additional changes predicted for 2050 are a general decrease of sea level pressure (largest in the Bering sector) and an increase of precipitation. While predictions of changes in storminess cannot be made with confidence, the predicted reduction of sea ice cover will

  8. Dendro-provenancing of Arctic driftwood

    Science.gov (United States)

    Hellmann, Lena; Tegel, Willy; Geyer, Jan; Kirdyanov, Alexander V.; Nikolaev, Anatoly N.; Eggertsson, Ólafur; Altman, Jan; Reinig, Frederick; Morganti, Sandro; Wacker, Lukas; Büntgen, Ulf

    2017-04-01

    Arctic driftwood may represent a cross-disciplinary proxy archive at the interface of marine and terrestrial environments, which will likely gain in importance under future global climate change. Circumpolar network analyses that systematically consider species-specific boreal origin areas, transport routes and deposition characteristics of Arctic driftwood, are, however, missing. Here, we present tree-ring width (TRW) measurements of 2412 pine, larch and spruce driftwood samples from Greenland, Iceland, Svalbard, the Faroe Islands, and the Lena Delta in northeastern Siberia. Representing the largest Arctic driftwood TRW compilation, these data are compared against 495 TRW reference chronologies from the boreal forests of Eurasia and North America. The southern Yenisei region is the main source for recent pine driftwood at all Arctic sampling sites, whereas spruce mainly originates in western Russia and central Siberia, as well as in northern North America. Larch driftwood is, for the first time, dendro-provenanced to central and eastern Siberia. A new larch driftwood chronology extends the middle Lena River reference chronology back to 1203 CE. Annually resolved radiocarbon measurements further date six larch driftwood chronologies between 1294 and 2013 CE. Although being highly replicated, our study emphasizes the importance of interdisciplinary research efforts including radiocarbon dating, isotopic tracing and aDNA processing for improving Arctic driftwood provenancing in space and time. If successful, Arctic driftwood studies will contribute to the reconstruction of past boreal summer temperature variations and ocean current dynamics, as well as changes in sea ice extent and relative sea level over the last centuries to millennia.

  9. Arctic Warming as News - Perils and Possibilities

    Science.gov (United States)

    Revkin, A. C.

    2015-12-01

    A science journalist in his 30th year covering human-driven climate change, including on three Arctic reporting trips, reflects on successes and setbacks as news media, environmentalists and Arctic communities have tried to convey the significance of polar change to a public for which the ends of the Earth will always largely be a place of the imagination.Novel challenges are arising in the 24/7 online media environment, as when a paper by a veteran climate scientist proposing a mechanism for abrupt sea-level rise became a big news story before it was accepted by the open-review journal to which it had been submitted. New science is digging in on possible connections between changing Arctic sea ice and snow conditions and disruptive winter weather in more temperate northern latitudes, offering a potential link between this distant region and the lives of ordinary citizens. As cutting-edge research, such work gets substantial media attention. But, as with all new areas of inquiry, uncertainty dominates - creating the potential for distracting the public and policymakers from the many aspects of anthropogenic climate change that are firmly established - but, in a way, boring because of that.With the challenges, there are unprecedented opportunities for conveying Arctic science. In some cases, researchers on expeditions are partnering with media, offering both scientists and news outlets fresh ways to convey the story of Arctic change in an era of resource constraints.Innovative uses of crittercams, webcams, and satellite observations offer educators and interested citizens a way to track and appreciate Arctic change. But more can be done to engage the public directly without the news media as an intermediary, particularly if polar scientists or their institutions test some of the established practices honed by more experienced communicators at NASA.

  10. ARCTIC MONKEYS:猴子凶猛!

    Institute of Scientific and Technical Information of China (English)

    青鸟

    2007-01-01

    @@ 我不是成长于星条旗下的美利坚自由人民,所以英国乐队Arctic Monkeys在我跟前很能吃得开,打从我听到他们的第一个音符起.这或许是我从小看多了充满暴力的电视剧《西游记》,并对猴子产生了偏爱的缘故,而对Arctic Monkeys,来自北极的猴子,更是充满了好奇.

  11. Unmanned Platforms Monitor the Arctic Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    de Boer, Gijs; Ivey, Mark D.; Schmid, Beat; McFarlane, Sally A.; Petty, Rickey C.

    2016-02-22

    In the Arctic, drones and tethered balloons can make crucial atmospheric measurement to provide a unique perspective on an environment particularly vulnerable to climate change. Climate is rapidly changing all over the globe, but nowhere is that change faster than in the Arctic. The evidence from recent years is clear: Reductions in sea ice (Kwok and Unstersteiner, 2011) and permafrost (Romanovsky et al., 2002), in addition to modification of the terriestrial ecosystem through melting permafrost and shifting vegetation zones (burek et al., 2008; Sturm, et al., 2001), all point to a rapidly evolving.

  12. Massive phytoplankton blooms under Arctic sea ice.

    Science.gov (United States)

    Arrigo, Kevin R; Perovich, Donald K; Pickart, Robert S; Brown, Zachary W; van Dijken, Gert L; Lowry, Kate E; Mills, Matthew M; Palmer, Molly A; Balch, William M; Bahr, Frank; Bates, Nicholas R; Benitez-Nelson, Claudia; Bowler, Bruce; Brownlee, Emily; Ehn, Jens K; Frey, Karen E; Garley, Rebecca; Laney, Samuel R; Lubelczyk, Laura; Mathis, Jeremy; Matsuoka, Atsushi; Mitchell, B Greg; Moore, G W K; Ortega-Retuerta, Eva; Pal, Sharmila; Polashenski, Chris M; Reynolds, Rick A; Schieber, Brian; Sosik, Heidi M; Stephens, Michael; Swift, James H

    2012-06-15

    Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt ponds. The bloom was characterized by high diatom biomass and rates of growth and primary production. Evidence suggests that under-ice phytoplankton blooms may be more widespread over nutrient-rich Arctic continental shelves and that satellite-based estimates of annual primary production in these waters may be underestimated by up to 10-fold.

  13. Temperature and precipitation history of the Arctic

    DEFF Research Database (Denmark)

    Miller, G.H.; Alley, R.B.; Anderson, L.;

    2010-01-01

    in the tilt of Earth’s axis, but for the past 700 ka, glacial cycles have been longer, lasting w100 ka, separated by brief, warm interglaciations, when sea level and ice volumes were close to present. The cause of the shift from 41 ka to 100 ka glacial cycles is still debated. During the penultimate...... interglaciation, w130 to w120 ka ago, solar energy in summer in the Arctic was greater than at any time subsequently. As a consequence, Arctic summers werew5 C warmer than at present, and almost all glaciers melted completely except for the Greenland Ice Sheet, and even it was reduced in size substantially from...

  14. Exploring the diversity of Arctic eelpouts

    DEFF Research Database (Denmark)

    Ghigliotti, L.; Møller, Peter Rask; Cheng, C.-H. C.

    2012-01-01

    Zoarcidae (eelpouts), including 298 recognized valid species, is the most diverse family in the suborder Zoarcoidei (order Perciformes). Many of the species exhibit a great degree of phenotypic plasticity. In the present work, we analyze the genome of six Arctic species from the most diversified...... of the chromosomal features across species that apparently contrasts with the high level of inter-specific and intra-specific plasticity of morphological characters. The comparison between the chromosomal features of these Arctic eelpouts with those of the Antarctic species Lycodichthys dearborni (same subfamily...

  15. Arctic health policy: contribution of scientific data.

    Science.gov (United States)

    Berner, James E; Gilman, Andrew

    2003-08-01

    In Western Hemisphere arctic regions, scientific findings in humans, wildlife, and the environment have resulted in major governmental policy formulations. Government policy resulted in establishment of an effective international organization to address scientifically identified problems, including health disparities in arctic indigenous populations. Western scientific data and indigenous knowledge from initial international programs led to international agreements restricting certain persistent organic pollutants. In recent years, scientific data, and indigenous traditional knowledge, have resulted in governmental policy in the United States, Canada, and Nordic countries that includes the full participation of indigenous residents in defining research agendas, interpreting data, communicating information, and local community policy formulation.

  16. Strategy of the Italian Republic in the Arctic

    Directory of Open Access Journals (Sweden)

    Maria L. Lagutina

    2016-10-01

    Full Text Available This article is devoted to analysis of the interests of the Italian Republic in the Arctic. Despite the geographical distance Italy from the Arctic, the interest of Italians to the Arctic cooperation is due to historical reasons: Italians participated in the study of the Arctic since the end of the XIX century. That's scientific achievements in the field of Arctic studies have provided Italy's place in the "Arctic Club of non-Arctic countries". In 2013, Italy became an observer in the Arctic Council, and in 2016 the Italian Ministry of Foreign Affairs presented the document "Towards the Italian strategy for the Arctic", which shows the country's interests in the region to address climate change, the development of scientific co-operation and economic development of the region the participation of leading Italian companies. Thus, Italy marked the importance of the Arctic in the direction of its policy. Russia is one of the most important Italian partners in Arctic affairs. As economic interests are a priority for both sides, the main bilateral cooperation projects are focused on energy and transport.

  17. The role of the Arctic in future global petroleum supply

    Energy Technology Data Exchange (ETDEWEB)

    Lindholt, Lars; Glomsroed, Solveig

    2011-07-01

    The Arctic has a substantial share of global petroleum resources, but at higher costs than in most other petroleum provinces. Arctic states and petroleum companies are carefully considering the potential for future extraction in the Arctic. This paper studies the oil and gas supply from 6 arctic regions during 2010-2050 along with global economic growth and different assumptions regarding petroleum prices and resource endowments. Supply is calculated based on a global model of oil and gas markets. The data on undiscovered resources for the Arctic is based on the estimates by USGS. Sensitivity studies are carried out for two alternative price scenarios and for a 50 per cent reduction of arctic undiscovered resources compared with the USGS 2008 resource estimate. Although a major part of the undiscovered arctic petroleum resources is natural gas, our results show that the relative importance of the Arctic as a world gas supplier will decline, while its importance as a global oil producer may be maintained. We also show that less than full access to undiscovered oil resources will have minor effect on total arctic oil production and a marginal effect on arctic gas extraction. The reason is that Arctic Russia is an important petroleum producer with a sufficiently large stock of already discovered resources to support their petroleum production before 2050. (Author)

  18. Arctic security in an age of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Kraska, James (ed.)

    2013-03-01

    Publisher review: This book examines Arctic defense policy and military security from the perspective of all eight Arctic states. In light of climate change and melting ice in the Arctic Ocean, Canada, Russia, Denmark (Greenland), Norway and the United States, as well as Iceland, Sweden and Finland, are grappling with an emerging Arctic security paradigm. This volume brings together the world's most seasoned Arctic political-military experts from Europe and North America to analyze how Arctic nations are adapting their security postures to accommodate increased shipping, expanding naval presence, and energy and mineral development in the polar region. The book analyzes the ascent of Russia as the first 'Arctic superpower', the growing importance of polar security for NATO and the Nordic states, and the increasing role of Canada and the United States in the region.(Author)

  19. Arctic Health Research Center report no. 101: Combating mosquitoes in arctic Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers combating mosquitoes in Arctic Alaska. The physiology and biology of mosquitoes is discussed, followed by techniques to combated mosquitoes.

  20. Arctic Energy Technology Development Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sukumar Bandopadhyay; Charles Chamberlin; Robert Chaney; Gang Chen; Godwin Chukwu; James Clough; Steve Colt; Anthony Covescek; Robert Crosby; Abhijit Dandekar; Paul Decker; Brandon Galloway; Rajive Ganguli; Catherine Hanks; Rich Haut; Kristie Hilton; Larry Hinzman; Gwen Holdman; Kristie Holland; Robert Hunter; Ron Johnson; Thomas Johnson; Doug Kame; Mikhail Kaneveskly; Tristan Kenny; Santanu Khataniar; Abhijeet Kulkami; Peter Lehman; Mary Beth Leigh; Jenn-Tai Liang; Michael Lilly; Chuen-Sen Lin; Paul Martin; Pete McGrail; Dan Miller; Debasmita Misra; Nagendra Nagabhushana; David Ogbe; Amanda Osborne; Antoinette Owen; Sharish Patil; Rocky Reifenstuhl; Doug Reynolds; Eric Robertson; Todd Schaef; Jack Schmid; Yuri Shur; Arion Tussing; Jack Walker; Katey Walter; Shannon Watson; Daniel White; Gregory White; Mark White; Richard Wies; Tom Williams; Dennis Witmer; Craig Wollard; Tao Zhu

    2008-12-31

    The Arctic Energy Technology Development Laboratory was created by the University of Alaska Fairbanks in response to a congressionally mandated funding opportunity through the U.S. Department of Energy (DOE), specifically to encourage research partnerships between the university, the Alaskan energy industry, and the DOE. The enabling legislation permitted research in a broad variety of topics particularly of interest to Alaska, including providing more efficient and economical electrical power generation in rural villages, as well as research in coal, oil, and gas. The contract was managed as a cooperative research agreement, with active project monitoring and management from the DOE. In the eight years of this partnership, approximately 30 projects were funded and completed. These projects, which were selected using an industry panel of Alaskan energy industry engineers and managers, cover a wide range of topics, such as diesel engine efficiency, fuel cells, coal combustion, methane gas hydrates, heavy oil recovery, and water issues associated with ice road construction in the oil fields of the North Slope. Each project was managed as a separate DOE contract, and the final technical report for each completed project is included with this final report. The intent of this process was to address the energy research needs of Alaska and to develop research capability at the university. As such, the intent from the beginning of this process was to encourage development of partnerships and skills that would permit a transition to direct competitive funding opportunities managed from funding sources. This project has succeeded at both the individual project level and at the institutional development level, as many of the researchers at the university are currently submitting proposals to funding agencies, with some success.

  1. Arctic Synthesis Collaboratory: A Virtual Organization for Transformative Research and Education on a Changing Arctic

    Science.gov (United States)

    Warnick, W. K.; Wiggins, H. V.; Hinzman, L.; Holland, M.; Murray, M. S.; Vörösmarty, C.; Loring, A. J.

    2008-12-01

    About the Arctic Synthesis Collaboratory The Arctic Synthesis Collaboratory concept, developed through a series of NSF-funded workshops and town hall meetings, is envisioned as a cyber-enabled, technical, organizational, and social-synthesis framework to foster: • Interactions among interdisciplinary experts and stakeholders • Integrated data analysis and modeling activities • Training and development of the arctic science community • Delivery of outreach, education, and policy-relevant resources Scientific Rationale The rapid rate of arctic change and our incomplete understanding of the arctic system present the arctic community with a grand scientific challenge and three related issues. First, a wealth of observations now exists as disconnected data holdings, which must be coordinated and synthesized to fully detect and assess arctic change. Second, despite great strides in the development of arctic system simulations, we still have incomplete capabilities for modeling and predicting the behavior of the system as a whole. Third, policy-makers, stakeholders, and the public are increasingly making demands of the science community for forecasts and guidance in mitigation and adaptation strategies. Collaboratory Components The Arctic Synthesis Collaboratory is organized around four integrated functions that will be established virtually as a distributed set of activities, but also with the advantage of existing facilities that could sponsor some of the identified activities. Community Network "Meeting Grounds:" The Collaboratory will link distributed individuals, organizations, and activities to enable collaboration and foster new research initiatives. Specific activities could include: an expert directory, social networking services, and virtual and face-to-face meetings. Data Integration, Synthesis, and Modeling Activities: The Collaboratory will utilize appropriate tools to enable the combination of data and models. Specific activities could include: a web

  2. The Arctic Research Consortium of the United States (ARCUS)

    Science.gov (United States)

    Fox, S. E.; Wiggins, H. V.

    2011-12-01

    The Arctic Research Consortium of the United States (ARCUS) is a nonprofit membership organization composed of universities and institutions that have a substantial commitment to research in the Arctic. ARCUS was formed in 1988 to serve as a forum for planning, facilitating, coordinating, and implementing interdisciplinary studies of the Arctic; to act as a synthesizer and disseminator of scientific information on arctic research; and to educate scientists and the general public about the needs and opportunities for research in the Arctic. ARCUS, in collaboration with the broader science community, relevant agencies and organizations, and other stakeholders, coordinates science planning and educational activities across disciplinary and organizational boundaries. Examples of ARCUS projects include: - Arctic Sea Ice Outlook - an international effort that provides monthly summer reports synthesizing community estimates of the expected sea ice minimum. - Sea Ice for Walrus Outlook - a resource for Alaska Native subsistence hunters, coastal communities, and others that provides weekly reports with information on sea ice conditions relevant to walrus in Alaska waters. - PolarTREC (Teachers and Researchers Exploring and Collaborating) - a program whereby K-12 educators and researchers work together in hands-on field experiences in the Arctic and Antarctic to advance polar science education. - ArcticInfo mailing list, Witness the Arctic newsletter, and the Arctic Calendar - communication tools for the arctic science community to keep apprised of relevant news, meetings, and announcements. - Coordination for the Study of Environmental Arctic Change (SEARCH) program, which aims to provide scientific understanding of arctic environmental change to help society understand and respond to a rapidly changing Arctic.

  3. U.S. National Arctic Strategy: Preparing Defensive Lines of Effort for the Arctic

    Science.gov (United States)

    2014-04-01

    development in the Arctic and, due to limited abilities and financial resources to exploit the resources, international cooperation. Russia’s Arctic...the political agendas of Indonesia, Malaysia , and Singapore, but also to other nations protecting their own sea lines of communication. As such...presence, oversight, regulatory enforcement, and contingency response.55 Strategically, the Commandant of the Coast Guard recognizes the importance of

  4. The Useless Arctic: Exploiting Nature in the Arctic in the 1870s

    Directory of Open Access Journals (Sweden)

    Ulrike Spring

    2015-04-01

    Full Text Available What is the discursive genealogy of an ecological approach to the Arctic? Building on distinctions suggested by Francis Spufford and Gísli Pálsson, this article examines a specific juncture in the history of European–Arctic interaction – the reception of the Austro-Hungarian Arctic Expedition in 1874 – and traces the potential for ecological and relational understandings in what seems to be an orientalist and exploitative material. Examining the medial reception in Austria and in Norway, along with certain key texts in which Arctic wildlife is described, we find that the Norwegian reception of the expedition emphasizes practical issues connected with resource exploitation in the Arctic, while the Austrian reception mostly sees the Arctic as a symbolic resource with which to negotiate issues of identity and modernity. The Austrian discourse revolves around a set of paradoxical contradictions, the most central being those between materialism and idealism and emptiness and fullness; we argue it is the instability of such ambiguities which produces the possibility of a future ecological discourse.

  5. EU Engagement in the Arctic: Do the Policy Responses from the Arctic States Recognise the EU as a Legitimate Stakeholder?

    Directory of Open Access Journals (Sweden)

    Kamrul Hossain

    2015-11-01

    Full Text Available The Arctic states are bound in an institutional relationship by means of their actions through the Arctic Council (AC—an organisation created by the eight Arctic states. Although a number of its European Union (EU states are both members and observers in the AC, the EU is not, despite its clear stake in the Arctic, for of a number of reasons. The AC twice postponed the application of the EU in 2013; however, it granted the EU the right to observe the AC meetings as an “observer in principle.” In addition to the significant resource and commercial interests of the EU in the Arctic, it assumes a stewardship role in the Arctic. As the leader in combating global climate change, for example, the EU is committed to assuming responsibility for protecting the Arctic environment given that climate change does have a devastating impact in the Arctic. Moreover, the EU is also concerned about its and continental Europe's only indigenous people, the Sámi, a significant proportion of whom live in its Arctic member states of Finland and Sweden. Thus, in recent years, the EU has endorsed a series of policy documents concerning the Arctic. Against the background of this development, this article examines whether the policy responses of the Arctic states with regard to the EU's increased ambition to engage in Arctic matters make it a legitimate actor or stakeholder. The article concludes that even though the Arctic states, as the primary actors, determine the region's governance approach, they see also a general partnership role for the EU with regard to the common goals of knowledge-based responsible governance and sustainable development of the Arctic.

  6. Differentiation of Neonatal Human-Induced Pluripotent Stem Cells to Prostate Epithelial Cells: A Model to Study Prostate Cancer Development

    Science.gov (United States)

    2014-06-01

    1 AD_________________ Award Number: W81XWH-12-1-0189 TITLE: Differentiation of Neonatal Human...CONTRACT NUMBER Differentiation of Neonatal Human Induced Pluripotent Stem Cells to Prostate Epithelial Cells: A Model to Study Prostate Cancer...13. SUPPLEMENTARY NOTES 14. ABSTRACT We set out to establish conditions for differentiation of human neonatal foreskin skin fibroblast

  7. The Arctic Report Card: Communicating the State of the Rapidly Changing Arctic to a Diverse Audience via the Worldwide Web

    Science.gov (United States)

    Jeffries, M. O.; Richter-Menge, J.; Overland, J. E.; Soreide, N. N.

    2013-12-01

    Rapid change is occurring throughout the Arctic environmental system. The goal of the Arctic Report Card is to communicate the nature of the many changes to a diverse audience via the Worldwide Web. First published in 2006, the Arctic Report Card is a peer-reviewed publication containing clear, reliable and concise scientific information on the current state of the Arctic environment relative to observational records. Available only online, it is intended to be an authoritative source for scientists, teachers, students, decision-makers, policy-makers and the general public interested in the Arctic environment and science. The Arctic Report Card is organized into five sections: Atmosphere; Sea Ice & Ocean; Marine Ecosystem; Terrestrial Ecosystem; Terrestrial Cryosphere. Arctic Report Card 2012, the sixth annual update, comprised 20 essays on physical and biological topics prepared by an international team of 141 scientists from 15 different countries. For those who want a quick summary, the Arctic Report Card home page provides highlights of key events and findings, and a short video that is also available on YouTube. The release of the Report Card each autumn is preceded by a NOAA press release followed by a press conference, when the Web site is made public. The release of Arctic Report Card 2012 at an AGU Fall Meeting press conference on 5 December 2012 was subsequently reported by leading media organizations. The NOAA Arctic Web site, of which the Report Card is a part, is consistently at the top of Google search results for the keyword 'arctic', and the Arctic Report Card Web site tops search results for keyword "arctic report" - pragmatic indications of a Web site's importance and popularity. As another indication of the Web site's impact, in December 2012, the month when the 2012 update was released, the Arctic Report Card Web site was accessed by 19,851 unique sites in 105 countries, and 4765 Web site URLs referred to the Arctic Report Card. The 2012 Arctic

  8. Methane and Root Dynamics in Arctic Soil

    DEFF Research Database (Denmark)

    D'Imperio, Ludovica

    on the global climate. We investigated two aspects of arctic ecosystem dynamics which are not well represented in climatic models: i) soil methane (CH4) oxidation in dry heath tundra and barren soils and ii) root dynamics in wetlands. Field measurements were carried out during the growing season in Disko Island...

  9. Science Traverses in the Canadian High Arctic

    Science.gov (United States)

    Williamson, Marie-Claude

    2012-01-01

    The presentation is divided into three parts. Part I is an overview of early expeditions to the High Arctic, and their political consequences at the time. The focus then shifts to the Geological Survey of Canada s mapping program in the North (Operation Franklin), and to the Polar Continental Shelf Project (PCSP), a unique organization that resides within the Government of Canada s Department of Natural Resources, and supports mapping projects and science investigations. PCSP is highlighted throughout the presentation so a description of mandate, budgets, and support infrastructure is warranted. In Part II, the presenter describes the planning required in advance of scientific deployments carried out in the Canadian High Arctic from the perspective of government and university investigators. Field operations and challenges encountered while leading arctic field teams in fly camps are also described in this part of the presentation, with particular emphasis on the 2008 field season. Part III is a summary of preliminary results obtained from a Polar Survey questionnaire sent out to members of the Arctic research community in anticipation of the workshop. The last part of the talk is an update on the analog program at the Canadian Space Agency, specifically, the Canadian Analog Research Network (CARN) and current activities related to Analog missions, 2009-2010.

  10. Arctic Glitters With Shades of Harbin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chinese ice and snow art debuts in Finland Reindeer and panda stand side by side in front of a wall of bamboo paintings with flute and the cry of birds echoing nearby. Standing at the entrance of ICIUM-Wonderworld of Ice theme park, they greet visitors in a traditional Chinese way in the Arctic twilight.

  11. From Cold War to Arctic Battle?

    DEFF Research Database (Denmark)

    Jensen, Boris Brorman

    2012-01-01

    Greenland and the whole Arctic region is becoming a geopolitical hot spot. The opening of new potential sail routes to Asia and the possible exploitation of oil, gas and other natural resources like rare earth minerals are creating a window of opportunity for Greenland. What are the risks and who...

  12. Carbon dioxide in Arctic and subarctic regions

    Energy Technology Data Exchange (ETDEWEB)

    Gosink, T. A.; Kelley, J. J.

    1981-03-01

    A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

  13. Ocean acidification in the Western Arctic Ocean

    Science.gov (United States)

    Cai, W.; Chen, B.; Chen, L.

    2011-12-01

    We report carbonate chemistry and ocean acidification status in the western Arctic Ocean from 65-88οN based on data collected in summer 2008 and 2010. In the marginal seas, surface waters have high pH and high carbonate saturation state (Ω) due to intensive biological uptake of CO2. In the southern Canada Basin, surface waters have low pH and low Ω due to the uptake of atmospheric CO2 and sea-ice melt. In the northern Arctic Ocean basin, there is no serious ocean acidification in surface water due to heavy ice-coverage but pH and Ω in the subsurface waters at the oxygen minimum and nutrient maximum zone (at 100-150 m) are low due mostly to respiration-derived CO2 and an increased biological production and export in surface waters. Such multitude responses of ocean carbonate chemistry (northern vs. southern basin, basins vs. margins, and surface vs. subsurface) to climate changes are unique to the Arctic Ocean system. We will explore biogeochemical control mechanisms on carbonate chemistry and ocean acidification in the Arctic Ocean environments in the context of recent warming and sea-ice retreat.

  14. International arctic systems for observing the atmosphere

    DEFF Research Database (Denmark)

    Uttal, Taneil; Starkweather, Sandra; Drummond, James R.;

    2016-01-01

    IASOA activities and partnerships were initiated as a part of the 2007-2009 International Polar Year (IPY) and are expected to continue for many decades as a legacy program. The IASOA focus is on coordinating intensive measurements of the Arctic atmosphere collected in the U.S., Canada, Russia, N...

  15. Contrasts between Antarctic and Arctic ozone depletion.

    Science.gov (United States)

    Solomon, Susan; Portmann, Robert W; Thompson, David W J

    2007-01-09

    This work surveys the depth and character of ozone depletion in the Antarctic and Arctic using available long balloon-borne and ground-based records that cover multiple decades from ground-based sites. Such data reveal changes in the range of ozone values including the extremes observed as polar air passes over the stations. Antarctic ozone observations reveal widespread and massive local depletion in the heart of the ozone "hole" region near 18 km, frequently exceeding 90%. Although some ozone losses are apparent in the Arctic during particular years, the depth of the ozone losses in the Arctic are considerably smaller, and their occurrence is far less frequent. Many Antarctic total integrated column ozone observations in spring since approximately the 1980s show values considerably below those ever observed in earlier decades. For the Arctic, there is evidence of some spring season depletion of total ozone at particular stations, but the changes are much less pronounced compared with the range of past data. Thus, the observations demonstrate that the widespread and deep ozone depletion that characterizes the Antarctic ozone hole is a unique feature on the planet.

  16. Carbon dioxide exchange in the Arctic

    DEFF Research Database (Denmark)

    Ravn, Nynne Marie Rand

    Low temperatures in the Arctic have through geological times caused a build-up of carbon (C) in the soil while carbon dioxide (CO2) has been removed from the atmosphere, because ecosystem respiration (ER) has been exceeded by the photosynthesis (GEP). Increasing air temperature, as occurring...

  17. Moving Facts in an Arctic field

    DEFF Research Database (Denmark)

    Hastrup, Kirsten Blinkenberg; Flora, Janne; Andersen, Astrid Oberborbeck

    2016-01-01

    This article reflects on the merits of the expedition as an anthropological method on the basis of a recent cross-disciplinary experience, involving biologists, archaeologists and anthropologists working together in High Arctic Greenland. True to the term, the expedition had chartered a vessel from...

  18. Microbial Biogeography of the Arctic Cryosphere

    DEFF Research Database (Denmark)

    Hauptmann, Aviaja Zenia Edna Lyberth

    communities. This has considerably improved our understanding that even harsh and seemingly barren environments such as the cryosphere, the frozen parts of our planet, is inhabited by diverse life. This thesis presents three studies in microbial biogeography of the Arctic cryosphere utilizing a range of NGS...

  19. Do Arctic waders use adaptive wind drift?

    NARCIS (Netherlands)

    Green, M; Alerstam, T; Gudmundsson, GA; Hedenstrom, A; Piersma, T; Gudmundsson, Gudmundur A.; Hedenström, Anders

    2004-01-01

    We analysed five data sets of night directions of migrating arctic waders ill relation to,winds, recorded by tracking radar and optical range finder, in order to find out if these birds compensate for wind drift, or allow themselves to be drifted by winds. Our purpose was to investigate whether arct

  20. Life Found Lurking under Arctic Rocks

    Institute of Scientific and Technical Information of China (English)

    Sarah Graham; 刘晓

    2004-01-01

    @@ The Arctic tundra② would not appear a welcoming environment for life. But a paper published today in the journal Nature suggests that polar deserts may house photosynthetic③ organisms in a very unlikely place--under rocks. The discovery of the photosynthetic cyanobacteria④ could potentially double estimates of the carbon sequestration⑤ potential in these extreme environments.

  1. Recent Arctic Sea Level Variations from Satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Piccioni, Gaia

    2016-01-01

    Sea level monitoring in the Arctic region has always been an extreme challenge for remote sensing, and in particular for satellite altimetry. Despite more than two decades of observations, altimetry is still limited in the inner Arctic Ocean. We have developed an updated version of the Danish...... Technical University's (DTU) Arctic Ocean altimetric sea level timeseries starting in 1993 and now extended up to 2015 with CryoSat-2 data. The time-series covers a total of 23 years, which allows higher accuracy in sea level trend determination. The record shows a sea level trend of 2.2 ± 1.1 mm....../y for the region between 66°N and 82°N. In particular, a local increase of 15 mm/y is found in correspondence to the Beaufort Gyre. An early estimate of the mean sea level trend budget closure in the Arctic for the period 2005–2015 was derived by using the Equivalent Water Heights obtained from GRACE Tellus...

  2. The Arctic Ocean Perennial Ice Zone

    Science.gov (United States)

    Kwok, R.; Cunningham, G. F.; Yueh, S.

    1998-01-01

    This study shows that: 1) the NSCAT backscatter fields provide an estimate of the PIZ coverage of the Arctic Ocean; and, 2) the decrease in PIZ area over the winter gives an indication of the PIZ area exported through Fram Strait.

  3. Conflict Resolution Practices of Arctic Aboriginal Peoples

    NARCIS (Netherlands)

    R. Gendron; C. Hille

    2013-01-01

    This article presents an overview of the conflict resolution practices of indigenous populations in the Arctic. Among the aboriginal groups discussed are the Inuit, the Aleut, and the Saami. Having presented the conflict resolution methods, the authors discuss the types of conflicts that are current

  4. Towards seasonal Arctic shipping route predictions

    Science.gov (United States)

    Melia, N.; Haines, K.; Hawkins, E.; Day, J. J.

    2017-08-01

    The continuing decline in Arctic sea-ice will likely lead to increased human activity and opportunities for shipping in the region, suggesting that seasonal predictions of route openings will become ever more important. Here we present results from a set of ‘perfect model’ experiments to assess the predictability characteristics of the opening of Arctic sea routes. We find skilful predictions of the upcoming summer shipping season can be made from as early as January, although typically forecasts show lower skill before a May ‘predictability barrier’. We demonstrate that in forecasts started from January, predictions of route opening date are twice as uncertain as predicting the closing date and that the Arctic shipping season is becoming longer due to climate change, with later closing dates mostly responsible. We find that predictive skill is state dependent with predictions for high or low ice years exhibiting greater skill than medium ice years. Forecasting the fastest open water route through the Arctic is accurate to within 200 km when predicted from July, a six-fold increase in accuracy compared to forecasts initialised from the previous November, which are typically no better than climatology. Finally we find that initialisation of accurate summer sea-ice thickness information is crucial to obtain skilful forecasts, further motivating investment into sea-ice thickness observations, climate models, and assimilation systems.

  5. The European Arctic policy in progress

    Science.gov (United States)

    Conde Pérez, Elena; Yaneva, Zhaklin Valerieva

    2016-09-01

    The geostrategic, political, economic, and scientific relevance of the Arctic is constantly growing due to the complex process of climate change. Accordingly, the European Union-as a global political actor-, is already taking steps to ensure and strengthen its influence in the region while demonstrating readiness to face the many opportunities and challenges ahead in cooperation with the traditional stakeholders. Therefore, in order to reflect the renewed importance of the Arctic transformation, the Union has been designing its Arctic Policy focusing on climate change mitigation and multilateral cooperation as its main strengths. Unfortunately, despite the diligence and impetus that has been invested, this process has been delayed in several occasions as the Union had to deal with internal and external destabilizing factors, such as the later immigration crisis or the lack of uniformity among its member states' foreign policy interests. These factors will be analyzed along with the process of creation and development of the EU's Arctic policy. Despite some delays, on 27 April 2016, the long-awaited third communication was issued and progress has been made: even if, in general terms, the new document remains a political statement, there is also a clear commitment to action.

  6. Trichinella in arctic, subarctic and temperate regions

    DEFF Research Database (Denmark)

    Kapel, C. M O

    1997-01-01

    The transmission and occurrence of Trichinella spp according to the zoogeography of different climatic conditions, socioeconomy and human activity are discussed. Comparing arctic, subarctic and temperate regions, it appears that the species of Trichinella present, the composition of the fauna and...

  7. Shallow freshwater ecosystems of the circumpolar Arctic

    DEFF Research Database (Denmark)

    Rautio, Milla; Dufresne, France; Laurion, Isabelle

    2011-01-01

    This review provides a synthesis of limnological data and conclusions from studies on ponds and small lakes at our research sites in Subarctic and Arctic Canada, Alaska, northern Scandinavia, and Greenland. Many of these water bodies contain large standing stocks of benthic microbial mats that gr...

  8. The Arctic - A New Region for China's Foreign Policy

    Directory of Open Access Journals (Sweden)

    V S Yagiya

    2015-12-01

    Full Text Available Article is devoted to foreign policy of China in the Arctic. Main attention is paid to strategic view of the China concerning the Arctic, to bilateral and multilateral cooperation on the Arctic issues, also to opinion of Russian experts about discussing of Russian-China economic partnership. It was shown interests of the People's Republic of China in the Arctic: use Arctic transport system from the Pacific Rim to Europe; possibility of access to the Arctic resources; seeks of partners for the realized of Arctic projects and programs. It was pointed six directions of China cooperation in the Arctic: a scientific researches, b natural minerals, oil and gas issues, c tourism, d routes of the Arctic navigation, e use of high technologies in development of regional economy, e cooperation in the cultural and educational spheres. Authors are summarized that at the initial stage of the international cooperation in the Arctic polar scientific researches become as the tool of “he soft power”, and in the long term - the Northern Sea Route of the Russian Federation is included in the Strategy of China Economic belt and the Maritime Silk Route in the XXI century.

  9. Changing Export of Dissolved Black Carbon from Arctic Rivers

    Science.gov (United States)

    Stubbins, A.; Spencer, R. G.; Mann, P. J.; Dittmar, T.; Niggemann, J.; Holmes, R. M.; McClelland, J. W.

    2014-12-01

    Arctic rivers carry black carbon (BC) from Arctic soils to the ocean, linking two of the largest carbon stores on Earth. Wildfires have charred biomass since land plants emerged. BC, a refractory component of char, has accumulated in soils. In the oceans, dissolved BC (DBC) has also accumulated. Here we use samples and data collected as part of the long-term, high temporal resolution Arctic Great Rivers Observatory to model export of DBC from the six largest Arctic Rivers. Scaling to the pan-Arctic catchment, we report that ~3 million tons of DBC are delivered to the Arctic Ocean each year, which is ~8% of dissolved organic carbon loads to the Arctic Ocean. We suggest the transfer of Arctic river DBC to areas of deep water formation is a major source of DBC to the deep ocean carbon store. As the Arctic warms, greater wildfire occurrence is expected to produce more BC and changing hydrology and permafrost thaw to promote DBC export. Thus, the transfer of BC from Arctic soils to the ocean is predicted to increase.

  10. Modeling the summertime Arctic cloudy boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Curry, J.A.; Pinto, J.O. [Univ. of Colorado, Boulder, CO (United States); McInnes, K.L. [CSIRO Division of Atmospheric Research, Mordialloc (Australia)

    1996-04-01

    Global climate models have particular difficulty in simulating the low-level clouds during the Arctic summer. Model problems are exacerbated in the polar regions by the complicated vertical structure of the Arctic boundary layer. The presence of multiple cloud layers, a humidity inversion above cloud top, and vertical fluxes in the cloud that are decoupled from the surface fluxes, identified in Curry et al. (1988), suggest that models containing sophisticated physical parameterizations would be required to accurately model this region. Accurate modeling of the vertical structure of multiple cloud layers in climate models is important for determination of the surface radiative fluxes. This study focuses on the problem of modeling the layered structure of the Arctic summertime boundary-layer clouds and in particular, the representation of the more complex boundary layer type consisting of a stable foggy surface layer surmounted by a cloud-topped mixed layer. A hierarchical modeling/diagnosis approach is used. A case study from the summertime Arctic Stratus Experiment is examined. A high-resolution, one-dimensional model of turbulence and radiation is tested against the observations and is then used in sensitivity studies to infer the optimal conditions for maintaining two separate layers in the Arctic summertime boundary layer. A three-dimensional mesoscale atmospheric model is then used to simulate the interaction of this cloud deck with the large-scale atmospheric dynamics. An assessment of the improvements needed to the parameterizations of the boundary layer, cloud microphysics, and radiation in the 3-D model is made.

  11. Arctic carbon sinks: Present and future

    Science.gov (United States)

    Walsh, John J.

    1989-12-01

    Surface air temperatures of the Arctic rose 1.2° -1.5°C from 1880 to 1980, in contrast to a global warming of only 0.4° -0.5°C; since 1980, six of the warmest years in the past century have been observed. Polar enhancement of a temperature rise, induced possibly by anthropogenic release of "greenhouse" gases, CO2, N2O, CH4, and freons, to the atmosphere, is attributed to altered ice/snow albedo at sea level, i.e., melting of sea ice. A 5% decline of sea ice extent in the Arctic and Antarctic from 1979 to 1987 may have resulted in increased light availability within previously ice-covered polar regions. If such a short-term trend were to continue, it might lead to a negative biogeochemical feedback, i.e., enhanced extraction of atmospheric CO2 during marine photosynthesis. As a consequence of deep vertical mixing in the Antarctic Ocean, however, primary production during the austral summer may have actually declined in response to a reduction in extent of meltwater regions, where stratified water columns allow carbon fixation tenfold that of open water. In contrast, within shallow adjacent seas of the Arctic Ocean, where shelf regions are tenfold larger than those of the Antarctic, the positive global consequences of greenhouse warming at polar latitudes will probably be felt first. Specifically, the Pacific-influenced regions of the Chukchi and East Siberian Seas, where sufficient nutrients and shallow depths prevail, now have annual primary productions of >200 g C m-2 yr-1, tenfold that of other high Arctic shelves, and may supply 50% of the carbon respiration demands within the halocline of the deep Canadian and Eurasian basins via brine-mediated runoff. Continued melting of ice in the Arctic could increase by an order of magnitude the present CO2 sink of ˜0.1 × 109 t C yr-1.

  12. Report on the Arctic ozone loss workshop

    Energy Technology Data Exchange (ETDEWEB)

    Rex, M. [Alfred Wegener Institute, Potsdam, (Germany); Toohey, D. [University of Colorado, Boulder (United States); Harris, N.R.P. [EORCU, Cambridge (United Kingdom)

    2002-07-01

    Over the past decade tremendous progress has been made toward quantifying and understanding ozone loss in the Arctic stratosphere. Today a variety of approaches exist to quantify the degree of chemical loss over the course of an Arctic winter. Some have been used in a consistent way for many years and have produced a record of the inter-annual variability. On the other hand, a wide range of chemical models have been used to understand the processes in the wintertime Arctic stratosphere and to calculate the degree of ozone loss. An active scientific discussion has started about the level of maturity of up to date chemical models of the polar stratospheric chemistry. How well are observations of the ozone loss rate reproduced? How complete is our current quantitative understanding of the involved chemical and micro-physical processes? Are discrepancies between model results and observations larger than the combined known uncertainties? In the published literature the answers to these questions are controversial. Over the next few years one of the major challenges for the stratospheric research community will be to predict the future of the Arctic ozone layer in a scenario of decreasing stratospheric halogen loading and possible changes in climate. A solid assessment of our ability to reproduce currently observed ozone losses with model calculations is indispensable to determine the requirements for future research and to correctly interpret the reliability of model based predictions. To address these issues, the Arctic Ozone Loss Workshop was held on 4-6 March in Potsdam, Germany, hosted by the Alfred-Wegener-Institute for Polar and Marine Research. About 70 scientists from Europe, the US, Japan, Russia and New Zealand have participated. The workshop covered five sessions that are summarised in the following. (authors)

  13. Arctic and Antarctic sea ice and climate

    Science.gov (United States)

    Barreira, S.

    2014-12-01

    Principal Components Analysis in T-Mode Varimax rotated was performed on Antarctic and Arctic monthly sea ice concentration anomalies (SICA) fields for the period 1979-2014, in order to investigate which are the main spatial characteristics of sea ice and its relationship with atmospheric circulation. This analysis provides 5 patterns of sea ice for inter-spring period and 3 patterns for summer-autumn for Antarctica (69,2% of the total variance) and 3 different patterns for summer-autumn and 3 for winter-spring season for the Arctic Ocean (67,8% of the total variance).Each of these patterns has a positive and negative phase. We used the Monthly Polar Gridded Sea Ice Concentrations database derived from satellite information generated by NASA Team algorithm. To understand the links between the SICA and climate trends, we extracted the mean pressure and, temperature field patterns for the months with high loadings (positive or negative) of the sea ice patterns that gave distinct atmospheric structures associated with each one. For Antarctica, the first SICA spatial winter-spring pattern in positive phase shows a negative SICA centre over the Drake Passage and north region of Bellingshausen and Weddell Seas together with another negative SICA centre over the East Indian Ocean. Strong positive centres over the rest of the Atlantic and Indian Oceans basins and the Amundsen Sea are also presented. A strong negative pressure anomaly covers most of the Antarctic Continent centered over the Bellingshausen Sea accompanied by three positive pressure anomalies in middle-latitudes. During recent years, the Arctic showed persistent associations of sea-ice and climate patterns principally during summer. Our strongest summer-autumn pattern in negative phase showed a marked reduction on SICA over western Arctic, primarily linked to an overall increase in Arctic atmospheric temperature most pronounced over the Beaufort, Chukchi and East Siberian Seas, and a positive anomaly of

  14. The Arctic Ocean's seasonal cycle must change

    Science.gov (United States)

    Carton, James; Ding, Yanni

    2015-04-01

    This paper discusses anticipated changes to the seasonal cycle of the Arctic Ocean along with Arctic surface climate due to the reduction of seasonal sea ice cover expected in the 21st century. Net surface shortwave radiation is a function of surface reflectivity and atmospheric transparency as well as solar declination. Recent observational studies and modeling results presented here strongly suggest that this excess heat in the summer is currently being stored locally in the form of ocean warming and sea ice melt. This heat is lost in winter/spring through surface loss through longwave and turbulent processes causing ocean cooling and the refreezing of sea ice. A striking feature of Arctic climate during the 20th century has been the enhanced warming experienced during winter in response to increases in anthropogenic greenhouse gasses. The amplitude of the seasonal cycle of surface air temperature is declining by gradually warming winter temperatures relative to summer temperatures. Bintanja and van der Linden (2013) show this process will eventually cause the 30C seasonal change in air temperature to reduce by half as seasonal sea ice disappears. The much weaker seasonal cycle of ocean temperature, which is controlled by the need to store excess surface heat seasonally, is also going to be affected by the loss of sea ice but in quite different ways. In particular the ocean will need to compensate for the loss of seasonal heat storage by the ice pack. This study examines consequences for the Arctic Ocean stratification and circulation in a suite of CMIP5 models under future emissions scenarios relative to their performance during the 20th century and to explore a range of model ocean responses to declining sea ice cover on the Arctic Ocean.

  15. The effects of radiative and microphysical processes on simulated warm and transition season arctic stratus

    Science.gov (United States)

    Harrington, Jerry Y.

    A cloud-resolving model (CRM) version of RAMS, coupled to explicit bin resolving microphysics and a new two-stream radiative transfer code is used to study various aspects of Arctic stratus clouds (ASC). The two-stream radiative transfer model is coupled in a consistent fashion to the bulk microphysical parameterization of Walko et al., (1995), an explicit liquid bin microphysical model (e.g., Feingold et al., 1996a) and a mixed-phase microphysical model (Reisin et al., 1996). These models are used to study both warm (summer) season and transition (fall and spring) season ASC. Equations are developed for the inclusion of the radiative term in the drop growth equation and the effect is studied in a trajectory parcel model (TPM) and the CRM. Arctic stratus simulated with the new CRM framework compared well with the observations of Curry (1986). Along with CCN concentrations, it is shown that drop distribution shape and optical property methods strongly impact cloud evolution through their effect on the radiative properties. Broader cloud top distributions lead to clouds with more shallow depths and circulation strengths as more shortwave radiation is absorbed while the opposite occurs for narrow distribution functions. Radiative-cloud interactions using mean effective radii are shown to be problematic, while conserving re and N of the distribution function (as per Hu and Stamnes, 1993) produces similar cloud evolution as compared to detailed computations. Radiative effects on drop vapor deposition growth can produce drizzle about 30 minutes earlier and is strongly dependent upon cloud top residence time of the parcels. The same set of trajectories assists drizzle production in the radiation and no-radiation cases. Not only is the growth of larger drops enhanced by the radiative effect, but drops with rCRM show a smaller impact of the radiative influence; this is attributed to the spurious production of cloud top supersaturations by Eulerian models (Stevens et al

  16. Pan-Arctic observations in GRENE Arctic Climate Change Research Project and its successor

    Science.gov (United States)

    Yamanouchi, Takashi

    2016-04-01

    We started a Japanese initiative - "Arctic Climate Change Research Project" - within the framework of the Green Network of Excellence (GRENE) Program, funded by the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT), in 2011. This Project targeted understanding and forecasting "Rapid Change of the Arctic Climate System and its Global Influences." Four strategic research targets are set by the Ministry: 1. Understanding the mechanism of warming amplification in the Arctic; 2. Understanding the Arctic climate system for global climate and future change; 3. Evaluation of the impacts of Arctic change on the weather and climate in Japan, marine ecosystems and fisheries; 4. Projection of sea ice distribution and Arctic sea routes. Through a network of universities and institutions in Japan, this 5-year Project involves more than 300 scientists from 39 institutions and universities. The National Institute of Polar Research (NIPR) works as the core institute and The Japan Agency for Marine- Earth Science and Technology (JAMSTEC) joins as the supporting institute. There are 7 bottom up research themes approved: the atmosphere, terrestrial ecosystems, cryosphere, greenhouse gases, marine ecology and fisheries, sea ice and Arctic sea routes and climate modeling, among 22 applications. The Project will realize multi-disciplinal study of the Arctic region and connect to the projection of future Arctic and global climatic change by modeling. The project has been running since the beginning of 2011 and in those 5 years pan-Arctic observations have been carried out in many locations, such as Svalbard, Russian Siberia, Alaska, Canada, Greenland and the Arctic Ocean. In particular, 95 GHz cloud profiling radar in high precision was established at Ny-Ålesund, Svalbard, and intensive atmospheric observations were carried out in 2014 and 2015. In addition, the Arctic Ocean cruises by R/V "Mirai" (belonging to JAMSTEC) and other icebreakers belonging to other

  17. May I Cut in? Gene Editing Approaches in Human Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Brookhouser, Nicholas; Raman, Sreedevi; Potts, Christopher; Brafman, David A

    2017-02-06

    In the decade since Yamanaka and colleagues described methods to reprogram somatic cells into a pluripotent state, human induced pluripotent stem cells (hiPSCs) have demonstrated tremendous promise in numerous disease modeling, drug discovery, and regenerative medicine applications. More recently, the development and refinement of advanced gene transduction and editing technologies have further accelerated the potential of hiPSCs. In this review, we discuss the various gene editing technologies that are being implemented with hiPSCs. Specifically, we describe the emergence of technologies including zinc-finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 that can be used to edit the genome at precise locations, and discuss the strengths and weaknesses of each of these technologies. In addition, we present the current applications of these technologies in elucidating the mechanisms of human development and disease, developing novel and effective therapeutic molecules, and engineering cell-based therapies. Finally, we discuss the emerging technological advances in targeted gene editing methods.

  18. May I Cut in? Gene Editing Approaches in Human Induced Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Nicholas Brookhouser

    2017-02-01

    Full Text Available In the decade since Yamanaka and colleagues described methods to reprogram somatic cells into a pluripotent state, human induced pluripotent stem cells (hiPSCs have demonstrated tremendous promise in numerous disease modeling, drug discovery, and regenerative medicine applications. More recently, the development and refinement of advanced gene transduction and editing technologies have further accelerated the potential of hiPSCs. In this review, we discuss the various gene editing technologies that are being implemented with hiPSCs. Specifically, we describe the emergence of technologies including zinc-finger nuclease (ZFN, transcription activator-like effector nuclease (TALEN, and clustered regularly interspaced short palindromic repeats (CRISPR/Cas9 that can be used to edit the genome at precise locations, and discuss the strengths and weaknesses of each of these technologies. In addition, we present the current applications of these technologies in elucidating the mechanisms of human development and disease, developing novel and effective therapeutic molecules, and engineering cell-based therapies. Finally, we discuss the emerging technological advances in targeted gene editing methods.

  19. Human induced rotation and reorganization of the brain of domestic dogs.

    Directory of Open Access Journals (Sweden)

    Taryn Roberts

    Full Text Available Domestic dogs exhibit an extraordinary degree of morphological diversity. Such breed-to-breed variability applies equally to the canine skull, however little is known about whether this translates to systematic differences in cerebral organization. By looking at the paramedian sagittal magnetic resonance image slice of canine brains across a range of animals with different skull shapes (N = 13, we found that the relative reduction in skull length compared to width (measured by Cephalic Index was significantly correlated to a progressive ventral pitching of the primary longitudinal brain axis (r = 0.83, as well as with a ventral shift in the position of the olfactory lobe (r = 0.81. Furthermore, these findings were independent of estimated brain size or body weight. Since brachycephaly has arisen from generations of highly selective breeding, this study suggests that the remarkable diversity in domesticated dogs' body shape and size appears to also have led to human-induced adaptations in the organization of the canine brain.

  20. Natural and Human-Induced Dynamics on Big Hickory Island, Florida

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    Tiffany M. Roberts Briggs

    2016-02-01

    Full Text Available Big Hickory Island, located in Lee County along the mixed-energy west Florida coast, experiences high long-term rates of shoreline recession, with much of the erosion concentrated along the central and southern portions of the island. In 2013, approximately 86,300 cubic meters of sand from an adjacent tidal inlet to the north were placed along 457 m to restore the beach and dune system. In an effort to combat erosion, seven concrete king-pile groins with adjustable panels were constructed subsequent to the completion of the beach nourishment. Natural and human-induced dynamics of Big Hickory Island are discussed through analysis of shoreline and morphologic change using historic aerial photographs and topographic and bathymetric field surveys of the recent beach erosion mitigation project. Although much of the long-term anomalously high rates of erosion for the area are related to natural interchanges between the sand resources of the barrier islands and adjacent ebb tidal shoals, additional reduction in sand supply is a result of human-interventions updrift of Big Hickory over the last several decades. The coupled natural and anthropogenic influences are driving the coastal processes toward a different morphodynamic state than would have occurred under natural processes alone.

  1. Effects of oxidative and thermal stresses on stress granule formation in human induced pluripotent stem cells.

    Science.gov (United States)

    Palangi, Freshteh; Samuel, Samson M; Thompson, I Richard; Triggle, Chris R; Emara, Mohamed M

    2017-01-01

    Stress Granules (SGs) are dynamic ribonucleoprotein aggregates, which have been observed in cells subjected to environmental stresses, such as oxidative stress and heat shock (HS). Although pluripotent stem cells (PSCs) are highly sensitive to oxidative stress, the role of SGs in regulating PSC self-renewal and differentiation has not been fully elucidated. Here we found that sodium arsenite (SA) and HS, but not hydrogen peroxide (H2O2), induce SG formation in human induced (hi) PSCs. Particularly, we found that these granules contain the well-known SG proteins (G3BP, TIAR, eIF4E, eIF4A, eIF3B, eIF4G, and PABP), were found in juxtaposition to processing bodies (PBs), and were disassembled after the removal of the stress. Moreover, we showed that SA and HS, but not H2O2, promote eIF2α phosphorylation in hiPSCs forming SGs. Analysis of pluripotent protein expression showed that HS significantly reduced all tested markers (OCT4, SOX2, NANOG, KLF4, L1TD1, and LIN28A), while SA selectively reduced the expression levels of NANOG and L1TD1. Finally, in addition to LIN28A and L1TD1, we identified DPPA5 (pluripotent protein marker) as a novel component of SGs. Collectively, these results provide new insights into the molecular cues of hiPSCs responses to environmental insults.

  2. Reprogramming triggers endogenous L1 and Alu retrotransposition in human induced pluripotent stem cells.

    Science.gov (United States)

    Klawitter, Sabine; Fuchs, Nina V; Upton, Kyle R; Muñoz-Lopez, Martin; Shukla, Ruchi; Wang, Jichang; Garcia-Cañadas, Marta; Lopez-Ruiz, Cesar; Gerhardt, Daniel J; Sebe, Attila; Grabundzija, Ivana; Merkert, Sylvia; Gerdes, Patricia; Pulgarin, J Andres; Bock, Anja; Held, Ulrike; Witthuhn, Anett; Haase, Alexandra; Sarkadi, Balázs; Löwer, Johannes; Wolvetang, Ernst J; Martin, Ulrich; Ivics, Zoltán; Izsvák, Zsuzsanna; Garcia-Perez, Jose L; Faulkner, Geoffrey J; Schumann, Gerald G

    2016-01-08

    Human induced pluripotent stem cells (hiPSCs) are capable of unlimited proliferation and can differentiate in vitro to generate derivatives of the three primary germ layers. Genetic and epigenetic abnormalities have been reported by Wissing and colleagues to occur during hiPSC derivation, including mobilization of engineered LINE-1 (L1) retrotransposons. However, incidence and functional impact of endogenous retrotransposition in hiPSCs are yet to be established. Here we apply retrotransposon capture sequencing to eight hiPSC lines and three human embryonic stem cell (hESC) lines, revealing endogenous L1, Alu and SINE-VNTR-Alu (SVA) mobilization during reprogramming and pluripotent stem cell cultivation. Surprisingly, 4/7 de novo L1 insertions are full length and 6/11 retrotransposition events occurred in protein-coding genes expressed in pluripotent stem cells. We further demonstrate that an intronic L1 insertion in the CADPS2 gene is acquired during hiPSC cultivation and disrupts CADPS2 expression. These experiments elucidate endogenous retrotransposition, and its potential consequences, in hiPSCs and hESCs.

  3. Generation of large pig and bovine blastocysts by culturing in human induced pluripotent stem cell medium.

    Science.gov (United States)

    Gao, Qing-Shan; Jin, Long; Li, Suo; Zhu, Hai-Ying; Guo, Qing; Li, Xiao-Chen; Jin, Qing-Guo; Kang, Jin-Dan; Yan, Chang-Guo; Yin, Xi-Jun

    2016-04-01

    We investigated the effect of human induced pluripotent stem cell (hiPS) medium on porcine somatic cell nuclear transfer and bovine in vitro fertilized early blastocysts, in comparison with North Carolina State University (NCSU)-37 medium and in vitro culture (IVC)-II medium. After 2 days of culture, the diameter of the portion of the blastocyst that was extruded from the zona pellucid dramatically differed between porcine blastocysts cultured in hiPS medium and those cultured in NCSU-37 medium (221.47 ± 38.94 μm versus 481.87 ± 40.61 μm, P medium and those cultured in IVC-II medium (150.30 ± 29.49 μm versus 195.58 ± 41.59 μm, P cells per porcine and bovine blastocyst was more than two-fold higher in blastocysts cultured in hiPS medium than in those cultured in NCSU-37 medium (44.33 ± 5.28 and 143.33 ± 16.05, P medium (172.12 ± 45.08 and 604.83 ± 242.64, P medium markedly improves the quality of porcine and bovine blastocysts.

  4. Disease Modeling and Phenotypic Drug Screening for Diabetic Cardiomyopathy using Human Induced Pluripotent Stem Cells

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    Faye M. Drawnel

    2014-11-01

    Full Text Available Diabetic cardiomyopathy is a complication of type 2 diabetes, with known contributions of lifestyle and genetics. We develop environmentally and genetically driven in vitro models of the condition using human-induced-pluripotent-stem-cell-derived cardiomyocytes. First, we mimic diabetic clinical chemistry to induce a phenotypic surrogate of diabetic cardiomyopathy, observing structural and functional disarray. Next, we consider genetic effects by deriving cardiomyocytes from two diabetic patients with variable disease progression. The cardiomyopathic phenotype is recapitulated in the patient-specific cells basally, with a severity dependent on their original clinical status. These models are incorporated into successive levels of a screening platform, identifying drugs that preserve cardiomyocyte phenotype in vitro during diabetic stress. In this work, we present a patient-specific induced pluripotent stem cell (iPSC model of a complex metabolic condition, showing the power of this technique for discovery and testing of therapeutic strategies for a disease with ever-increasing clinical significance.

  5. Generation of dendritic cells and macrophages from human induced pluripotent stem cells aiming at cell therapy.

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    Senju, S; Haruta, M; Matsumura, K; Matsunaga, Y; Fukushima, S; Ikeda, T; Takamatsu, K; Irie, A; Nishimura, Y

    2011-09-01

    This report describes generation of dendritic cells (DCs) and macrophages from human induced pluripotent stem (iPS) cells. iPS cell-derived DC (iPS-DC) exhibited the morphology of typical DC and function of T-cell stimulation and antigen presentation. iPS-DC loaded with cytomegalovirus (CMV) peptide induced vigorous expansion of CMV-specific autologous CD8+ T cells. Macrophages (iPS-MP) with activity of zymosan phagocytosis and C5a-induced chemotaxis were also generated from iPS cells. Genetically modified iPS-MPs were generated by the introduction of expression vectors into undifferentiated iPS cells, isolation of transfectant iPS cell clone and subsequent differentiation. By this procedure, we generated iPS-MP expressing a membrane-bound form of single chain antibody (scFv) specific to amyloid β (Aβ), the causal protein of Alzheimer's disease. The scFv-transfectant iPS-MP exhibited efficient Aβ-specific phagocytosis activity. iPS-MP expressing CD20-specific scFv engulfed and killed BALL-1 B-cell leukemia cells. Anti-BALL-1 effect of iPS-MP in vivo was demonstrated in a xeno-transplantation model using severe combined immunodeficient mice. In addition, we established a xeno-free culture protocol to generate iPS-DC and iPS-MP. Collectively, we demonstrated the possibility of application of iPS-DC and macrophages to cell therapy.

  6. The human-induced pluripotent stem cell initiative—data resources for cellular genetics

    Science.gov (United States)

    Streeter, Ian; Harrison, Peter W.; Faulconbridge, Adam; Flicek, Paul; Parkinson, Helen; Clarke, Laura

    2017-01-01

    The Human Induced Pluripotent Stem Cell Initiative (HipSci) isf establishing a large catalogue of human iPSC lines, arguably the most well characterized collection to date. The HipSci portal enables researchers to choose the right cell line for their experiment, and makes HipSci's rich catalogue of assay data easy to discover and reuse. Each cell line has genomic, transcriptomic, proteomic and cellular phenotyping data. Data are deposited in the appropriate EMBL-EBI archives, including the European Nucleotide Archive (ENA), European Genome-phenome Archive (EGA), ArrayExpress and PRoteomics IDEntifications (PRIDE) databases. The project will make 500 cell lines from healthy individuals, and from 150 patients with rare genetic diseases; these will be available through the European Collection of Authenticated Cell Cultures (ECACC). As of August 2016, 238 cell lines are available for purchase. Project data is presented through the HipSci data portal (http://www.hipsci.org/lines) and is downloadable from the associated FTP site (ftp://ftp.hipsci.ebi.ac.uk/vol1/ftp). The data portal presents a summary matrix of the HipSci cell lines, showing available data types. Each line has its own page containing descriptive metadata, quality information, and links to archived assay data. Analysis results are also available in a Track Hub, allowing visualization in the context of public genomic annotations (http://www.hipsci.org/data/trackhubs). PMID:27733501

  7. The human-induced pluripotent stem cell initiative-data resources for cellular genetics.

    Science.gov (United States)

    Streeter, Ian; Harrison, Peter W; Faulconbridge, Adam; Flicek, Paul; Parkinson, Helen; Clarke, Laura

    2017-01-04

    The Human Induced Pluripotent Stem Cell Initiative (HipSci) isf establishing a large catalogue of human iPSC lines, arguably the most well characterized collection to date. The HipSci portal enables researchers to choose the right cell line for their experiment, and makes HipSci's rich catalogue of assay data easy to discover and reuse. Each cell line has genomic, transcriptomic, proteomic and cellular phenotyping data. Data are deposited in the appropriate EMBL-EBI archives, including the European Nucleotide Archive (ENA), European Genome-phenome Archive (EGA), ArrayExpress and PRoteomics IDEntifications (PRIDE) databases. The project will make 500 cell lines from healthy individuals, and from 150 patients with rare genetic diseases; these will be available through the European Collection of Authenticated Cell Cultures (ECACC). As of August 2016, 238 cell lines are available for purchase. Project data is presented through the HipSci data portal (http://www.hipsci.org/lines) and is downloadable from the associated FTP site (ftp://ftp.hipsci.ebi.ac.uk/vol1/ftp). The data portal presents a summary matrix of the HipSci cell lines, showing available data types. Each line has its own page containing descriptive metadata, quality information, and links to archived assay data. Analysis results are also available in a Track Hub, allowing visualization in the context of public genomic annotations (http://www.hipsci.org/data/trackhubs). © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  8. Derivation of Corneal Keratocyte-Like Cells from Human Induced Pluripotent Stem Cells

    Science.gov (United States)

    Naylor, Richard W.; McGhee, Charles N. J.; Cowan, Chad A.; Davidson, Alan J.; Holm, Teresa M.; Sherwin, Trevor

    2016-01-01

    Corneal diseases such as keratoconus represent a relatively common disorder in the human population. However, treatment is restricted to corneal transplantation, which only occurs in the most advanced cases. Cell based therapies may offer an alternative approach given that the eye is amenable to such treatments and corneal diseases like keratoconus have been associated specifically with the death of corneal keratocytes. The ability to generate corneal keratocytes in vitro may enable a cell-based therapy to treat patients with keratoconus. Human induced pluripotent stem cells (hiPSCs) offer an abundant supply of cells from which any cell in the body can be derived. In the present study, hiPSCs were successfully differentiated into neural crest cells (NCCs), the embryonic precursor to keratocytes, and then cultured on cadaveric corneal tissue to promote keratocyte differentiation. The hiPSC-derived NCCs were found to migrate into the corneal stroma where they acquired a keratocyte-like morphology and an expression profile similar to corneal keratocytes in vivo. These results indicate that hiPSCs can be used to generate corneal keratocytes in vitro and lay the foundation for using these cells in cornea cell-based therapies. PMID:27792791

  9. Human induced pluripotent stem cell-derived models to investigate human cytomegalovirus infection in neural cells.

    Directory of Open Access Journals (Sweden)

    Leonardo D'Aiuto

    Full Text Available Human cytomegalovirus (HCMV infection is one of the leading prenatal causes of congenital mental retardation and deformities world-wide. Access to cultured human neuronal lineages, necessary to understand the species specific pathogenic effects of HCMV, has been limited by difficulties in sustaining primary human neuronal cultures. Human induced pluripotent stem (iPS cells now provide an opportunity for such research. We derived iPS cells from human adult fibroblasts and induced neural lineages to investigate their susceptibility to infection with HCMV strain Ad169. Analysis of iPS cells, iPS-derived neural stem cells (NSCs, neural progenitor cells (NPCs and neurons suggests that (i iPS cells are not permissive to HCMV infection, i.e., they do not permit a full viral replication cycle; (ii Neural stem cells have impaired differentiation when infected by HCMV; (iii NPCs are fully permissive for HCMV infection; altered expression of genes related to neural metabolism or neuronal differentiation is also observed; (iv most iPS-derived neurons are not permissive to HCMV infection; and (v infected neurons have impaired calcium influx in response to glutamate.

  10. Cell-autonomous correction of ring chromosomes in human induced pluripotent stem cells

    Science.gov (United States)

    Bershteyn, Marina; Hayashi, Yohei; Desachy, Guillaume; Hsiao, Edward C.; Sami, Salma; Tsang, Kathryn M.; Weiss, Lauren A.; Kriegstein, Arnold R.; Yamanaka, Shinya; Wynshaw-Boris, Anthony

    2014-03-01

    Ring chromosomes are structural aberrations commonly associated with birth defects, mental disabilities and growth retardation. Rings form after fusion of the long and short arms of a chromosome, and are sometimes associated with large terminal deletions. Owing to the severity of these large aberrations that can affect multiple contiguous genes, no possible therapeutic strategies for ring chromosome disorders have been proposed. During cell division, ring chromosomes can exhibit unstable behaviour leading to continuous production of aneuploid progeny with low viability and high cellular death rate. The overall consequences of this chromosomal instability have been largely unexplored in experimental model systems. Here we generated human induced pluripotent stem cells (iPSCs) from patient fibroblasts containing ring chromosomes with large deletions and found that reprogrammed cells lost the abnormal chromosome and duplicated the wild-type homologue through the compensatory uniparental disomy (UPD) mechanism. The karyotypically normal iPSCs with isodisomy for the corrected chromosome outgrew co-existing aneuploid populations, enabling rapid and efficient isolation of patient-derived iPSCs devoid of the original chromosomal aberration. Our results suggest a fundamentally different function for cellular reprogramming as a means of `chromosome therapy' to reverse combined loss-of-function across many genes in cells with large-scale aberrations involving ring structures. In addition, our work provides an experimentally tractable human cellular system for studying mechanisms of chromosomal number control, which is of critical relevance to human development and disease.

  11. May I Cut in? Gene Editing Approaches in Human Induced Pluripotent Stem Cells

    Science.gov (United States)

    Brookhouser, Nicholas; Raman, Sreedevi; Potts, Christopher; Brafman, David. A.

    2017-01-01

    In the decade since Yamanaka and colleagues described methods to reprogram somatic cells into a pluripotent state, human induced pluripotent stem cells (hiPSCs) have demonstrated tremendous promise in numerous disease modeling, drug discovery, and regenerative medicine applications. More recently, the development and refinement of advanced gene transduction and editing technologies have further accelerated the potential of hiPSCs. In this review, we discuss the various gene editing technologies that are being implemented with hiPSCs. Specifically, we describe the emergence of technologies including zinc-finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 that can be used to edit the genome at precise locations, and discuss the strengths and weaknesses of each of these technologies. In addition, we present the current applications of these technologies in elucidating the mechanisms of human development and disease, developing novel and effective therapeutic molecules, and engineering cell-based therapies. Finally, we discuss the emerging technological advances in targeted gene editing methods. PMID:28178187

  12. Human induced pluripotent stem cells for monogenic disease modelling and therapy

    Institute of Scientific and Technical Information of China (English)

    Paola; Spitalieri; Valentina; Rosa; Talarico; Michela; Murdocca; Giuseppe; Novelli; Federica; Sangiuolo

    2016-01-01

    Recent and advanced protocols are now available toderive human induced pluripotent stem cells(hi PSCs)from patients affected by genetic diseases.No curative treatments are available for many of these diseases;thus,hiP SCs represent a major impact on patient’health.hiP SCs represent a valid model for the in vitro study of monogenic diseases,together with a better comprehension of the pathogenic mechanisms of the pathology,for both cell and gene therapy protocol applications.Moreover,these pluripotent cells represent a good opportunity to test innovative pharmacological treatments focused on evaluating the efficacy and toxicity of novel drugs.Today,innovative gene therapy protocols,especially gene editingbased,are being developed,allowing the use of these cells not only as in vitro disease models but also as an unlimited source of cells useful for tissue regeneration and regenerative medicine,eluding ethical and immune rejection problems.In this review,we will provide an upto-date of modelling monogenic disease by using hiP SCs and the ultimate applications of these in vitro models for cell therapy.We consider and summarize some peculiar aspects such as the type of parental cells used for reprogramming,the methods currently used to induce the transcription of the reprogramming factors,and the type of iP SC-derived differentiated cells,relating them to the genetic basis of diseases and to their inheritance model.

  13. Study of mitochondrial respiratory defects on reprogramming to human induced pluripotent stem cells

    Science.gov (United States)

    Hung, Sandy S.C.; Van Bergen, Nicole J.; Jackson, Stacey; Liang, Helena; Mackey, David A.; Hernández, Damián; Lim, Shiang Y.; Hewitt, Alex W.; Trounce, Ian; Pébay, Alice; Wong, Raymond C.B.

    2016-01-01

    Reprogramming of somatic cells into a pluripotent state is known to be accompanied by extensive restructuring of mitochondria and switch in metabolic requirements. Here we utilized Leber's hereditary optic neuropathy (LHON) as a mitochondrial disease model to study the effects of homoplasmic mtDNA mutations and subsequent oxidative phosphorylation (OXPHOS) defects in reprogramming. We obtained fibroblasts from a total of 6 LHON patients and control subjects, and showed a significant defect in complex I respiration in LHON fibroblasts by high-resolution respiratory analysis. Using episomal vector reprogramming, our results indicated that human induced pluripotent stem cell (hiPSC) generation is feasible in LHON fibroblasts. In particular, LHON-specific OXPHOS defects in fibroblasts only caused a mild reduction and did not significantly affect reprogramming efficiency, suggesting that hiPSC reprogramming can tolerate a certain degree of OXPHOS defects. Our results highlighted the induction of genes involved in mitochondrial biogenesis (TFAM, NRF1), mitochondrial fusion (MFN1, MFN2) and glycine production (GCAT) during reprogramming. However, LHON-associated OXPHOS defects did not alter the kinetics or expression levels of these genes during reprogramming. Together, our study provides new insights into the effects of mtDNA mutation and OXPHOS defects in reprogramming and genes associated with various aspects of mitochondrial biology. PMID:27127184

  14. Generation of glycosylphosphatidylinositol anchor protein-deficient blood cells from human induced pluripotent stem cells.

    Science.gov (United States)

    Yuan, Xuan; Braunstein, Evan M; Ye, Zhaohui; Liu, Cyndi F; Chen, Guibin; Zou, Jizhong; Cheng, Linzhao; Brodsky, Robert A

    2013-11-01

    PIG-A is an X-linked gene required for the biosynthesis of glycosylphosphatidylinositol (GPI) anchors; thus, PIG-A mutant cells have a deficiency or absence of all GPI-anchored proteins (GPI-APs). Acquired mutations in hematopoietic stem cells result in the disease paroxysmal nocturnal hemoglobinuria, and hypomorphic germline PIG-A mutations lead to severe developmental abnormalities, seizures, and early death. Human induced pluripotent stem cells (iPSCs) can differentiate into cell types derived from all three germ layers, providing a novel developmental system for modeling human diseases. Using PIG-A gene targeting and an inducible PIG-A expression system, we have established, for the first time, a conditional PIG-A knockout model in human iPSCs that allows for the production of GPI-AP-deficient blood cells. PIG-A-null iPSCs were unable to generate hematopoietic cells or any cells expressing the CD34 marker and were defective in generating mesodermal cells expressing KDR/VEGFR2 (kinase insert domain receptor) and CD56 markers. In addition, PIG-A-null iPSCs had a block in embryonic development prior to mesoderm differentiation that appears to be due to defective signaling through bone morphogenetic protein 4. However, early inducible PIG-A transgene expression allowed for the generation of GPI-AP-deficient blood cells. This conditional PIG-A knockout model should be a valuable tool for studying the importance of GPI-APs in hematopoiesis and human development.

  15. Generation of Integration-free Human Induced Pluripotent Stem Cells Using Hair-derived Keratinocytes.

    Science.gov (United States)

    Hung, Sandy S C; Pébay, Alice; Wong, Raymond C B

    2015-08-20

    Recent advances in reprogramming allow us to turn somatic cells into human induced pluripotent stem cells (hiPSCs). Disease modeling using patient-specific hiPSCs allows the study of the underlying mechanism for pathogenesis, also providing a platform for the development of in vitro drug screening and gene therapy to improve treatment options. The promising potential of hiPSCs for regenerative medicine is also evident from the increasing number of publications (>7000) on iPSCs in recent years. Various cell types from distinct lineages have been successfully used for hiPSC generation, including skin fibroblasts, hematopoietic cells and epidermal keratinocytes. While skin biopsies and blood collection are routinely performed in many labs as a source of somatic cells for the generation of hiPSCs, the collection and subsequent derivation of hair keratinocytes are less commonly used. Hair-derived keratinocytes represent a non-invasive approach to obtain cell samples from patients. Here we outline a simple non-invasive method for the derivation of keratinocytes from plucked hair. We also provide instructions for maintenance of keratinocytes and subsequent reprogramming to generate integration-free hiPSC using episomal vectors.

  16. Scalable Generation of Universal Platelets from Human Induced Pluripotent Stem Cells

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    Qiang Feng

    2014-11-01

    Full Text Available Human induced pluripotent stem cells (iPSCs provide a potentially replenishable source for the production of transfusable platelets. Here, we describe a method to generate megakaryocytes (MKs and functional platelets from iPSCs in a scalable manner under serum/feeder-free conditions. The method also permits the cryopreservation of MK progenitors, enabling a rapid “surge” capacity when large numbers of platelets are needed. Ultrastructural/morphological analyses show no major differences between iPSC platelets and human blood platelets. iPSC platelets form aggregates, lamellipodia, and filopodia after activation and circulate in macrophage-depleted animals and incorporate into developing mouse thrombi in a manner identical to human platelets. By knocking out the β2-microglobulin gene, we have generated platelets that are negative for the major histocompatibility antigens. The scalable generation of HLA-ABC-negative platelets from a renewable cell source represents an important step toward generating universal platelets for transfusion as well as a potential strategy for the management of platelet refractoriness.

  17. Error-Correcting Output Codes in Classification of Human Induced Pluripotent Stem Cell Colony Images

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    Henry Joutsijoki

    2016-01-01

    Full Text Available The purpose of this paper is to examine how well the human induced pluripotent stem cell (hiPSC colony images can be classified using error-correcting output codes (ECOC. Our image dataset includes hiPSC colony images from three classes (bad, semigood, and good which makes our classification task a multiclass problem. ECOC is a general framework to model multiclass classification problems. We focus on four different coding designs of ECOC and apply to each one of them k-Nearest Neighbor (k-NN searching, naïve Bayes, classification tree, and discriminant analysis variants classifiers. We use Scaled Invariant Feature Transformation (SIFT based features in classification. The best accuracy (62.4% is obtained with ternary complete ECOC coding design and k-NN classifier (standardized Euclidean distance measure and inverse weighting. The best result is comparable with our earlier research. The quality identification of hiPSC colony images is an essential problem to be solved before hiPSCs can be used in practice in large-scale. ECOC methods examined are promising techniques for solving this challenging problem.

  18. Selective cell targeting and lineage tracing of human induced pluripotent stem cells using recombinant avian retroviruses.

    Science.gov (United States)

    Hildebrand, Laura; Seemann, Petra; Kurtz, Andreas; Hecht, Jochen; Contzen, Jörg; Gossen, Manfred; Stachelscheid, Harald

    2015-12-01

    Human induced pluripotent stem cells (hiPSC) differentiate into multiple cell types. Selective cell targeting is often needed for analyzing gene function by overexpressing proteins in a distinct population of hiPSC-derived cell types and for monitoring cell fate in response to stimuli. However, to date, this has not been possible, as commonly used viruses enter the hiPSC via ubiquitously expressed receptors. Here, we report for the first time the application of a heterologous avian receptor, the tumor virus receptor A (TVA), to selectively transduce TVA(+) cells in a mixed cell population. Expression of the TVA surface receptor via genetic engineering renders cells susceptible for infection by avian leucosis virus (ALV). We generated hiPSC lines with this stably integrated, ectopic TVA receptor gene that expressed the receptor while retaining pluripotency. The undifferentiated hiPSC(TVA+) as well as their differentiating progeny could be infected by recombinant ALV (so-called RCAS virus) with high efficiency. Due to incomplete receptor blocking, even sequential infection of differentiating or undifferentiated TVA(+) cells was possible. In conclusion, the TVA/RCAS system provides an efficient and gentle gene transfer system for hiPSC and extends our possibilities for selective cell targeting and lineage tracing studies.

  19. Specification of Region-Specific Neurons Including Forebrain Glutamatergic Neurons from Human Induced Pluripotent Stem Cells

    Science.gov (United States)

    Martins-Taylor, Kristen; Wang, Xiaofang; Zhang, Zheng; Park, Jung Woo; Zhan, Shuning; Kronenberg, Mark S.; Lichtler, Alexander; Liu, Hui-Xia; Chen, Fang-Ping; Yue, Lixia; Li, Xue-Jun; Xu, Ren-He

    2010-01-01

    Background Directed differentiation of human induced pluripotent stem cells (hiPSC) into functional, region-specific neural cells is a key step to realizing their therapeutic promise to treat various neural disorders, which awaits detailed elucidation. Methodology/Principal Findings We analyzed neural differentiation from various hiPSC lines generated by others and ourselves. Although heterogeneity in efficiency of neuroepithelial (NE) cell differentiation was observed among different hiPSC lines, the NE differentiation process resembles that from human embryonic stem cells (hESC) in morphology, timing, transcriptional profile, and requirement for FGF signaling. NE cells differentiated from hiPSC, like those from hESC, can also form rostral phenotypes by default, and form the midbrain or spinal progenitors upon caudalization by morphogens. The rostrocaudal neural progenitors can further mature to develop forebrain glutamatergic projection neurons, midbrain dopaminergic neurons, and spinal motor neurons, respectively. Typical ion channels and action potentials were recorded in the hiPSC-derived neurons. Conclusions/Significance Our results demonstrate that hiPSC, regardless of how they were derived, can differentiate into a spectrum of rostrocaudal neurons with functionality, which supports the considerable value of hiPSC for study and treatment of patient-specific neural disorders. PMID:20686615

  20. Identification of a specific reprogramming-associated epigenetic signature in human induced pluripotent stem cells.

    Science.gov (United States)

    Ruiz, Sergio; Diep, Dinh; Gore, Athurva; Panopoulos, Athanasia D; Montserrat, Nuria; Plongthongkum, Nongluk; Kumar, Sachin; Fung, Ho-Lim; Giorgetti, Alessandra; Bilic, Josipa; Batchelder, Erika M; Zaehres, Holm; Kan, Natalia G; Schöler, Hans Robert; Mercola, Mark; Zhang, Kun; Izpisua Belmonte, Juan Carlos

    2012-10-02

    Generation of human induced pluripotent stem cells (hiPSCs) by the expression of specific transcription factors depends on successful epigenetic reprogramming to a pluripotent state. Although hiPSCs and human embryonic stem cells (hESCs) display a similar epigenome, recent reports demonstrated the persistence of specific epigenetic marks from the somatic cell type of origin and aberrant methylation patterns in hiPSCs. However, it remains unknown whether the use of different somatic cell sources, encompassing variable levels of selection pressure during reprogramming, influences the level of epigenetic aberrations in hiPSCs. In this work, we characterized the epigenomic integrity of 17 hiPSC lines derived from six different cell types with varied reprogramming efficiencies. We demonstrate that epigenetic aberrations are a general feature of the hiPSC state and are independent of the somatic cell source. Interestingly, we observe that the reprogramming efficiency of somatic cell lines inversely correlates with the amount of methylation change needed to acquire pluripotency. Additionally, we determine that both shared and line-specific epigenetic aberrations in hiPSCs can directly translate into changes in gene expression in both the pluripotent and differentiated states. Significantly, our analysis of different hiPSC lines from multiple cell types of origin allow us to identify a reprogramming-specific epigenetic signature comprised of nine aberrantly methylated genes that is able to segregate hESC and hiPSC lines regardless of the somatic cell source or differentiation state.

  1. Donor-dependent variations in hepatic differentiation from human-induced pluripotent stem cells.

    Science.gov (United States)

    Kajiwara, Masatoshi; Aoi, Takashi; Okita, Keisuke; Takahashi, Ryosuke; Inoue, Haruhisa; Takayama, Naoya; Endo, Hiroshi; Eto, Koji; Toguchida, Junya; Uemoto, Shinji; Yamanaka, Shinya

    2012-07-31

    Hepatocytes generated from human induced pluripotent stem cells (hiPSCs) are unprecedented resources for pharmaceuticals and cell therapy. However, the in vitro directed differentiation of human pluripotent stem cells into mature hepatocytes remains challenging. Little attention has so far been paid to variations among hiPSC lines in terms of their hepatic differentiation. In the current study, we developed an improved hepatic differentiation protocol and compared 28 hiPSC lines originated from various somatic cells and derived using retroviruses, Sendai viruses, or episomal plasmids. This comparison indicated that the origins, but not the derivation methods, may be a major determinant of variation in hepatic differentiation. The hiPSC clones derived from peripheral blood cells consistently showed good differentiation efficiency, whereas many hiPSC clones from adult dermal fibroblasts showed poor differentiation. However, when we compared hiPSCs from peripheral blood and dermal fibroblasts from the same individuals, we found that variations in hepatic differentiation were largely attributable to donor differences, rather than to the types of the original cells. These data underscore the importance of donor differences when comparing the differentiation propensities of hiPSC clones.

  2. Error-Correcting Output Codes in Classification of Human Induced Pluripotent Stem Cell Colony Images.

    Science.gov (United States)

    Joutsijoki, Henry; Haponen, Markus; Rasku, Jyrki; Aalto-Setälä, Katriina; Juhola, Martti

    2016-01-01

    The purpose of this paper is to examine how well the human induced pluripotent stem cell (hiPSC) colony images can be classified using error-correcting output codes (ECOC). Our image dataset includes hiPSC colony images from three classes (bad, semigood, and good) which makes our classification task a multiclass problem. ECOC is a general framework to model multiclass classification problems. We focus on four different coding designs of ECOC and apply to each one of them k-Nearest Neighbor (k-NN) searching, naïve Bayes, classification tree, and discriminant analysis variants classifiers. We use Scaled Invariant Feature Transformation (SIFT) based features in classification. The best accuracy (62.4%) is obtained with ternary complete ECOC coding design and k-NN classifier (standardized Euclidean distance measure and inverse weighting). The best result is comparable with our earlier research. The quality identification of hiPSC colony images is an essential problem to be solved before hiPSCs can be used in practice in large-scale. ECOC methods examined are promising techniques for solving this challenging problem.

  3. Ketamine Causes Mitochondrial Dysfunction in Human Induced Pluripotent Stem Cell-Derived Neurons

    Science.gov (United States)

    Ito, Hiroyuki; Uchida, Tokujiro; Makita, Koshi

    2015-01-01

    Purpose Ketamine toxicity has been demonstrated in nonhuman mammalian neurons. To study the toxic effect of ketamine on human neurons, an experimental model of cultured neurons from human induced pluripotent stem cells (iPSCs) was examined, and the mechanism of its toxicity was investigated. Methods Human iPSC-derived dopaminergic neurons were treated with 0, 20, 100 or 500 μM ketamine for 6 and 24 h. Ketamine toxicity was evaluated by quantification of caspase 3/7 activity, reactive oxygen species (ROS) production, mitochondrial membrane potential, ATP concentration, neurotransmitter reuptake activity and NADH/NAD+ ratio. Mitochondrial morphological change was analyzed by transmission electron microscopy and confocal microscopy. Results Twenty-four-hour exposure of iPSC-derived neurons to 500 μM ketamine resulted in a 40% increase in caspase 3/7 activity (P ketamine (100 μM) decreased the ATP level (22%, P ketamine concentration, which suggests that mitochondrial dysfunction preceded ROS generation and caspase activation. Conclusions We established an in vitro model for assessing the neurotoxicity of ketamine in iPSC-derived neurons. The present data indicate that the initial mitochondrial dysfunction and autophagy may be related to its inhibitory effect on the mitochondrial electron transport system, which underlies ketamine-induced neural toxicity. Higher ketamine concentration can induce ROS generation and apoptosis in human neurons. PMID:26020236

  4. Experimental and Numerical Assessment of the Dynamical Behaviour of a Footbridge Under Human-Induced Loads

    Directory of Open Access Journals (Sweden)

    Santos da Silva José Guilherme

    2015-01-01

    Full Text Available This research aims to perform an experimental and numerical assessment of an existing pedestrian footbridge located in the campus of the State University of Rio de Janeiro (UERJ, Rio de Janeiro/RJ, Brazil. The structural system is based on an internal reinforced concrete footbridge spanning 24.5m, constituted by concrete beams and slabs and being currently used for pedestrian crossing. The modal testing of the structure was performed by dynamic monitoring through accelerometers installed on the structure as well as by a vibrometer device based on Laser Doppler Vibrometry using the SIMO and SISO acquisition techniques, respectively. Then, these experimental results were calibrated with a numerical model by the use of finite element method (FEM through the ANSYS program. Afterwards, a forced vibration analysis was performed on the structure based on human-induced loads considering two control groups: the first one is intended to excite the investigated footbridge to cause resonance motion with a controlled step frequency and the second one is related to freely random people crossing the footbridge as it occurs normally during its real life. Thus, the structural system dynamic response in terms of peak accelerations values were evaluated and compared to the current human comfort criteria.

  5. Mineralized gelatin methacrylate-based matrices induce osteogenic differentiation of human induced pluripotent stem cells

    Science.gov (United States)

    Kang, Heemin; Shih, Yu-Ru V.; Hwang, Yongsung; Wen, Cai; Rao, Vikram; Seo, Timothy; Varghese, Shyni

    2014-01-01

    Human induced pluripotent stem cells (hiPSCs) are a promising cell source with pluripotency and self-renewal properties. Design of simple and robust biomaterials with an innate ability to induce lineage-specificity of hiPSCs is desirable to realize their applications in regenerative medicine. In this study, we investigated the potential of biomaterials containing calcium phosphate minerals to induce osteogenic differentiation of hiPSCs. hiPSCs cultured using mineralized gelatin methacrylate-based matrices underwent osteogenic differentiation ex vivo, both in two- dimensional (2-D) and three-dimensional (3-D) cultures, in growth medium devoid of any osteogenic-inducing chemical components or growth factors. Our findings that osteogenic differentiation of hiPSCs can be achieved through biomaterial-based cues alone present new avenues for personalized regenerative medicine. Such biomaterials that could not only act as structural scaffolds, but could also provide tissue-specific functions such as directing stem cell differentiation commitment, have great potential in bone tissue engineering. PMID:25153779

  6. Differentiation of Human Induced Pluripotent Stem Cells to Mammary-like Organoids

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    Ying Qu

    2017-02-01

    Full Text Available Human induced pluripotent stem cells (iPSCs can give rise to multiple cell types and hold great promise in regenerative medicine and disease-modeling applications. We have developed a reliable two-step protocol to generate human mammary-like organoids from iPSCs. Non-neural ectoderm-cell-containing spheres, referred to as mEBs, were first differentiated and enriched from iPSCs using MammoCult medium. Gene expression profile analysis suggested that mammary gland function-associated signaling pathways were hallmarks of 10-day differentiated mEBs. We then generated mammary-like organoids from 10-day mEBs using 3D floating mixed gel culture and a three-stage differentiation procedure. These organoids expressed common breast tissue, luminal, and basal markers, including estrogen receptor, and could be induced to produce milk protein. These results demonstrate that human iPSCs can be directed in vitro toward mammary lineage differentiation. Our findings provide an iPSC-based model for studying regulation of normal mammary cell fate and function as well as breast disease development.

  7. Scalable generation of universal platelets from human induced pluripotent stem cells.

    Science.gov (United States)

    Feng, Qiang; Shabrani, Namrata; Thon, Jonathan N; Huo, Hongguang; Thiel, Austin; Machlus, Kellie R; Kim, Kyungho; Brooks, Julie; Li, Feng; Luo, Chenmei; Kimbrel, Erin A; Wang, Jiwu; Kim, Kwang-Soo; Italiano, Joseph; Cho, Jaehyung; Lu, Shi-Jiang; Lanza, Robert

    2014-11-11

    Human induced pluripotent stem cells (iPSCs) provide a potentially replenishable source for the production of transfusable platelets. Here, we describe a method to generate megakaryocytes (MKs) and functional platelets from iPSCs in a scalable manner under serum/feeder-free conditions. The method also permits the cryopreservation of MK progenitors, enabling a rapid "surge" capacity when large numbers of platelets are needed. Ultrastructural/morphological analyses show no major differences between iPSC platelets and human blood platelets. iPSC platelets form aggregates, lamellipodia, and filopodia after activation and circulate in macrophage-depleted animals and incorporate into developing mouse thrombi in a manner identical to human platelets. By knocking out the β2-microglobulin gene, we have generated platelets that are negative for the major histocompatibility antigens. The scalable generation of HLA-ABC-negative platelets from a renewable cell source represents an important step toward generating universal platelets for transfusion as well as a potential strategy for the management of platelet refractoriness.

  8. Differentiation of Human Induced Pluripotent Stem Cells to Mammary-like Organoids.

    Science.gov (United States)

    Qu, Ying; Han, Bingchen; Gao, Bowen; Bose, Shikha; Gong, Yiping; Wawrowsky, Kolja; Giuliano, Armando E; Sareen, Dhruv; Cui, Xiaojiang

    2017-02-14

    Human induced pluripotent stem cells (iPSCs) can give rise to multiple cell types and hold great promise in regenerative medicine and disease-modeling applications. We have developed a reliable two-step protocol to generate human mammary-like organoids from iPSCs. Non-neural ectoderm-cell-containing spheres, referred to as mEBs, were first differentiated and enriched from iPSCs using MammoCult medium. Gene expression profile analysis suggested that mammary gland function-associated signaling pathways were hallmarks of 10-day differentiated mEBs. We then generated mammary-like organoids from 10-day mEBs using 3D floating mixed gel culture and a three-stage differentiation procedure. These organoids expressed common breast tissue, luminal, and basal markers, including estrogen receptor, and could be induced to produce milk protein. These results demonstrate that human iPSCs can be directed in vitro toward mammary lineage differentiation. Our findings provide an iPSC-based model for studying regulation of normal mammary cell fate and function as well as breast disease development.

  9. Expandable and Rapidly Differentiating Human Induced Neural Stem Cell Lines for Multiple Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Dana M. Cairns

    2016-09-01

    Full Text Available Limited availability of human neurons poses a significant barrier to progress in biological and preclinical studies of the human nervous system. Current stem cell-based approaches of neuron generation are still hindered by prolonged culture requirements, protocol complexity, and variability in neuronal differentiation. Here we establish stable human induced neural stem cell (hiNSC lines through the direct reprogramming of neonatal fibroblasts and adult adipose-derived stem cells. These hiNSCs can be passaged indefinitely and cryopreserved as colonies. Independently of media composition, hiNSCs robustly differentiate into TUJ1-positive neurons within 4 days, making them ideal for innervated co-cultures. In vivo, hiNSCs migrate, engraft, and contribute to both central and peripheral nervous systems. Lastly, we demonstrate utility of hiNSCs in a 3D human brain model. This method provides a valuable interdisciplinary tool that could be used to develop drug screening applications as well as patient-specific disease models related to disorders of innervation and the brain.

  10. Modulating notochordal differentiation of human induced pluripotent stem cells using natural nucleus pulposus tissue matrix.

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    Yongxing Liu

    Full Text Available Human induced pluripotent stem cells (hiPSCs can differentiate into notochordal cell (NC-like cells when cultured in the presence of natural porcine nucleus pulposus (NP tissue matrix. The method promises massive production of high-quality, functional cells to treat degenerative intervertebral discs (IVDs. Based on our previous work, we further examined the effect of cell-NP matrix contact and culture medium on the differentiation, and further assessed the functional differentiation ability of the generated NC-like. The study showed that direct contact between hiPSCs and NP matrix can promote the differentiation yield, whilst both the contact and non-contact cultures can generate functional NC-like cells. The generated NC-like cells are highly homogenous regarding the expression of notochordal marker genes. A culture medium containing a cocktail of growth factors (FGF, EGF, VEGF and IGF-1 also supported the notochordal differentiation in the presence of NP matrix. The NC-like cells showed excellent functional differentiation ability to generate NP-like tissue which was rich in aggrecan and collagen type II; and particularly, the proteoglycan to collagen content ratio was as high as 12.5-17.5 which represents a phenotype close to NP rather than hyaline cartilage. Collectively, the present study confirmed the effectiveness and flexibility of using natural NP tissue matrix to direct notochordal differentiation of hiPSCs, and the potential of using the generated NC-like cells for treating IVD degeneration.

  11. Glycomics of human embryonic stem cells and human induced pluripotent stem cells.

    Science.gov (United States)

    Furukawa, Jun-Ichi; Okada, Kazue; Shinohara, Yasuro

    2016-10-01

    Most cells are coated by a dense glycocalyx composed of glycoconjugates such as glycosphingolipids, glycoproteins, and proteoglycans. The overall glycomic profile is believed to be crucial for the diverse roles of glycans, which are mediated by specific interactions that regulate cell-cell adhesion, the immune response, microbial pathogenesis, and other cellular events. Many cell surface markers were discovered and identified as glycoconjugates such as stage-specific embryonic antigen, Tra-1-60/81 and various other cell surface molecules (e.g., cluster of differentiation). Recent progress in the development of analytical methodologies and strategies has begun to clarify the cellular glycomics of various cells including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). The glycomic profiles of these cells are highly cell type-specific and reflect cellular alterations, such as development, differentiation and cancerous change. In this mini review, we briefly summarize the glycosylation spectra specific to hESCs and hiPSCs, which cover glycans of all major glycoconjugates (i.e., glycosphingolipids, N- and O-glycans of glycoproteins, and glycosaminoglycans) and free oligosaccharides.

  12. The collapse of the Maya: Effects of natural and human-induced drought

    Energy Technology Data Exchange (ETDEWEB)

    Oglesby, Robert J [ORNL; Erickson III, David J [ORNL

    2010-02-01

    The collapse of the Maya civilization during the ninth century A.D. is a major conundrum in the history of mankind. This civilization reached a spectacular peak but then almost completely collapsed in the space of a few decades. While numerous explanations have been put forth to explain this collapse, in recent years, drought has gained favor. This is because water resources were a key for the Maya, especially to ensure their survival during the lengthy dry season that occurs where they lived. Natural drought is a known, recurring feature of this region, as evidenced by observational data, reconstructions of past times, and global climate model output. Results from simulations with a regional climate model demonstrate that deforestation by the Maya also likely induced warmer, drier, drought-like conditions. It is therefore hypothesized that the drought conditions devastating the Maya resulted from a combination of natural variability and human activities. Neither the natural drought or the human-induced effects alone were sufficient to cause the collapse, but the combination created a situation the Maya could not recover from. These results may have sobering implications for the present and future state of climate and water resources in Mesoamerica as ongoing massive deforestation is again occurring.

  13. In vivo liver regeneration potential of human induced pluripotent stem cells from diverse origins.

    Science.gov (United States)

    Liu, Hua; Kim, Yonghak; Sharkis, Saul; Marchionni, Luigi; Jang, Yoon-Young

    2011-05-11

    Human induced pluripotent stem cells (iPSCs) are a potential source of hepatocytes for liver transplantation to treat end-stage liver disease. In vitro differentiation of human iPSCs into hepatic cells has been achieved using a multistage differentiation protocol, but whether these cells are functional and capable of engrafting and regenerating diseased liver tissue is not clear. We show that human iPSC-derived hepatic cells at various differentiation stages can engraft the liver in a mouse transplantation model. Using the same differentiation and transplantation protocols, we also assessed the ability of human iPSCs derived from each of the three developmental germ layer tissues (that is, ectoderm, mesoderm, and endoderm) to regenerate mouse liver. These iPSC lines, with similar but distinct global DNA methylation patterns, differentiated into multistage hepatic cells with an efficiency similar to that of human embryonic stem cells. Human hepatic cells at various differentiation stages derived from iPSC lines of different origins successfully repopulated the liver tissue of mice with liver cirrhosis. They also secreted human-specific liver proteins into mouse blood at concentrations comparable to that of proteins secreted by human primary hepatocytes. Our results demonstrate the engraftment and liver regenerative capabilities of human iPSC-derived multistage hepatic cells in vivo and suggest that human iPSCs of distinct origins and regardless of their parental epigenetic memory can efficiently differentiate along the hepatic lineage.

  14. Specification of region-specific neurons including forebrain glutamatergic neurons from human induced pluripotent stem cells.

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    Hui Zeng

    Full Text Available BACKGROUND: Directed differentiation of human induced pluripotent stem cells (hiPSC into functional, region-specific neural cells is a key step to realizing their therapeutic promise to treat various neural disorders, which awaits detailed elucidation. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed neural differentiation from various hiPSC lines generated by others and ourselves. Although heterogeneity in efficiency of neuroepithelial (NE cell differentiation was observed among different hiPSC lines, the NE differentiation process resembles that from human embryonic stem cells (hESC in morphology, timing, transcriptional profile, and requirement for FGF signaling. NE cells differentiated from hiPSC, like those from hESC, can also form rostral phenotypes by default, and form the midbrain or spinal progenitors upon caudalization by morphogens. The rostrocaudal neural progenitors can further mature to develop forebrain glutamatergic projection neurons, midbrain dopaminergic neurons, and spinal motor neurons, respectively. Typical ion channels and action potentials were recorded in the hiPSC-derived neurons. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that hiPSC, regardless of how they were derived, can differentiate into a spectrum of rostrocaudal neurons with functionality, which supports the considerable value of hiPSC for study and treatment of patient-specific neural disorders.

  15. Human Induced Pluripotent Stem Cells from Basic Research to Potential Clinical Applications in Cancer

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    Teresa de Souza Fernandez

    2013-01-01

    Full Text Available The human induced pluripotent stem cells (hiPSCs are derived from a direct reprogramming of human somatic cells to a pluripotent stage through ectopic expression of specific transcription factors. These cells have two important properties, which are the self-renewal capacity and the ability to differentiate into any cell type of the human body. So, the discovery of hiPSCs opens new opportunities in biomedical sciences, since these cells may be useful for understanding the mechanisms of diseases in the production of new diseases models, in drug development/drug toxicity tests, gene therapies, and cell replacement therapies. However, the hiPSCs technology has limitations including the potential for the development of genetic and epigenetic abnormalities leading to tumorigenicity. Nowadays, basic research in the hiPSCs field has made progress in the application of new strategies with the aim to enable an efficient production of high-quality of hiPSCs for safety and efficacy, necessary to the future application for clinical practice. In this review, we show the recent advances in hiPSCs’ basic research and some potential clinical applications focusing on cancer. We also present the importance of the use of statistical methods to evaluate the possible validation for the hiPSCs for future therapeutic use toward personalized cell therapies.

  16. Ozone variability and halogen oxidation within the Arctic and sub-Arctic springtime boundary layer

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    J. B. Gilman

    2010-11-01

    Full Text Available The influence of halogen oxidation on the variabilities of ozone (O3 and volatile organic compounds (VOCs within the Arctic and sub-Arctic atmospheric boundary layer was investigated using field measurements from multiple campaigns conducted in March and April 2008 as part of the POLARCAT project. For the ship-based measurements, a high degree of correlation (r = 0.98 for 544 data points collected north of 68° N was observed between the acetylene to benzene ratio, used as a marker for chlorine and bromine oxidation, and O3 signifying the vast influence of halogen oxidation throughout the ice-free regions of the North Atlantic. Concurrent airborne and ground-based measurements in the Alaskan Arctic substantiated this correlation and were used to demonstrate that halogen oxidation influenced O3 variability throughout the Arctic boundary layer during these springtime studies. Measurements aboard the R/V Knorr in the North Atlantic and Arctic Oceans provided a unique view of the transport of O3-poor air masses from the Arctic Basin to latitudes as far south as 52° N. FLEXPART, a Lagrangian transport model, was used to quantitatively determine the exposure of air masses encountered by the ship to first-year ice (FYI, multi-year ice (MYI, and total ICE (FYI+MYI. O3 anti-correlated with the modeled total ICE tracer (r = −0.86 indicating that up to 73% of the O3 variability measured in the Arctic marine boundary layer could be related to sea ice exposure.

  17. Research of legal status and navigation regime of arctic shipping lanes

    OpenAIRE

    Yu, Yue

    2016-01-01

    As the thawing of the sea ice within the Arctic Ocean, the Arctic is facing tremendous changes, including environment, economy, industry, culture and many other areas. As the sea ice decreasing, the Arctic region is becoming a “new world” opening its gate to the whole world. The most obvious aspect is about Arctic shipping issues. The Arctic Ocean is locating on special geographical point which closely connecting the Atlantic Ocean and Pacific Ocean. Furthermore, the Arctic Ocean has shorter ...

  18. Leading By Example: Canada and its Arctic Stewardship Role

    DEFF Research Database (Denmark)

    Burke, Danita Catherine

    2017-01-01

    . This paper explores the origins of Canada’s image as the steward of the Arctic environment which started with the 1970 Arctic Waters Pollution Prevention Act legislation and addresses the central research questions, how did Canada’s role as the steward of the Arctic environment begin and evolve and how...... to examine the circumstances which led to the creation and success of Canada’s stewardship role and its implications for Canadian and international shipping in the Arctic region before any changes are made to the governance of the region through unilateral legislation changes or new international agreements...... important is the Arctic Waters Pollution Prevention Act for international acceptance of Canada’s stewardship role and maritime jurisdiction in the Arctic region?...

  19. Can regional climate engineering save the summer Arctic sea ice?

    Science.gov (United States)

    Tilmes, S.; Jahn, Alexandra; Kay, Jennifer E.; Holland, Marika; Lamarque, Jean-Francois

    2014-02-01

    Rapid declines in summer Arctic sea ice extent are projected under high-forcing future climate scenarios. Regional Arctic climate engineering has been suggested as an emergency strategy to save the sea ice. Model simulations of idealized regional dimming experiments compared to a business-as-usual greenhouse gas emission simulation demonstrate the importance of both local and remote feedback mechanisms to the surface energy budget in high latitudes. With increasing artificial reduction in incoming shortwave radiation, the positive surface albedo feedback from Arctic sea ice loss is reduced. However, changes in Arctic clouds and the strongly increasing northward heat transport both counteract the direct dimming effects. A 4 times stronger local reduction in solar radiation compared to a global experiment is required to preserve summer Arctic sea ice area. Even with regional Arctic dimming, a reduction in the strength of the oceanic meridional overturning circulation and a shut down of Labrador Sea deep convection are possible.

  20. Future-Proofing Japan’s Interests in the Arctic

    DEFF Research Database (Denmark)

    Tonami, Aki

    2014-01-01

    credentials Japan has to be involved in the leading Arctic forum. However, a closer look at its engagement in the Arctic indicates that Japan has genuine interests in political, economic, and environmental developments there. This essay examines Japan’s interests in the Arctic, its new role as an observer......In May 2013 the Arctic states convened in Kiruna, Sweden, in part to decide on whether six new states should be admitted as observers to the Arctic Council. Japan’s application was accepted along with those of China,India, Italy, Singapore, and South Korea. At a glance, one might ask what...... to the Arctic Council, and the international relationships that will affect Japan’s engagement in the region....

  1. Biodiversity of Arctic marine ecosystems and responses to climate change

    DEFF Research Database (Denmark)

    Michel, C.; Bluhm, B.; Gallucci, V.

    2012-01-01

    The Arctic Ocean is undergoing major changes in many of its fundamental physical constituents, from a shift from multi- to first-year ice, shorter ice-covered periods, increasing freshwater runoff and surface stratification, to warming and alteration in the distribution of water masses...... that structure ecosystem biodiversity in the Arctic Ocean. We also discuss climateassociated effects on the biodiversity of Arctic marine ecosystems and discuss implications for the functioning of Arctic marine food webs. Based on the complexity and regional character of Arctic ecosystem reponses....... These changes have important impacts on the chemical and biological processes that are at the root of marine food webs, influencing their structure, function and biodiversity. Here we summarise current knowledge on the biodiversity of Arctic marine ecosystems and provide an overview of fundamental factors...

  2. Sea ice occurrence predicts genetic isolation in the Arctic fox.

    Science.gov (United States)

    Geffen, Eli; Waidyaratne, Sitara; Dalén, Love; Angerbjörn, Anders; Vila, Carles; Hersteinsson, Pall; Fuglei, Eva; White, Paula A; Goltsman, Michael; Kapel, Christian M O; Wayne, Robert K

    2007-10-01

    Unlike Oceanic islands, the islands of the Arctic Sea are not completely isolated from migration by terrestrial vertebrates. The pack ice connects many Arctic Sea islands to the mainland during winter months. The Arctic fox (Alopex lagopus), which has a circumpolar distribution, populates numerous islands in the Arctic Sea. In this study, we used genetic data from 20 different populations, spanning the entire distribution of the Arctic fox, to identify barriers to dispersal. Specifically, we considered geographical distance, occurrence of sea ice, winter temperature, ecotype, and the presence of red fox and polar bear as nonexclusive factors that influence the dispersal behaviour of individuals. Using distance-based redundancy analysis and the BIOENV procedure, we showed that occurrence of sea ice is the key predictor and explained 40-60% of the genetic distance among populations. In addition, our analysis identified the Commander and Pribilof Islands Arctic populations as genetically unique suggesting they deserve special attention from a conservation perspective.

  3. Decision Making For Sustainable Futures In A Rapidly Changing Arctic

    Science.gov (United States)

    Chabay, I.

    2016-12-01

    Observing, understanding, and predicting effects of rapid climate change in the Arctic are crucial as the circumpolar region becomes more accessible and demand grows for commercial development and resource extraction. Climate change effects - including changes in ocean ice coverage, Arctic weather patterns, permafrost conditions, and coastal erosion - are a consequence of fossil fuel use outside the Arctic, while at the same time the changes open greater access to the Arctic's rich resources, including oil and gas. This offers new opportunities for livelihoods and development of Arctic communities, but inevitably also introduces substantially increased environmental, social, and economic risks. I will outline the rationale for and the process of our transdisciplinary project in engaging with a wide range of actors in the Arctic and beyond. The purpose of the project is to support informed and effective decision making for sustainable futures that is contextually appropriate through co-design and co-production of knowledge with rights-holders and stakeholders.

  4. The Future of the Arctic: A Key to Global Sustainability

    Directory of Open Access Journals (Sweden)

    Francesco Stipo

    2012-10-01

    Full Text Available The USACOR Report forecasts that by 2050 the Arctic will become the major supplier of energy to the world, in particular oil and natural gas, and natural resources such as mineral water. In the coming decades, the population in the Arctic region is projected to increase significantly due to the expansion of exploration for resources. The Report recommends that a Zero emission policy be implemented throughout the Arctic area for water emissions into the seas, rivers, or estuaries and oceans. The Report recommends that the Arctic Council guarantees safe navigation and environmental protection, establishing a Fund to cover expenses to purchase icebreakers and towards the cost of the personnel in order to assist commercial navigation in the Arctic region. The Arctic Council shall also issue environmental rules to regulate the mineral exploitation in the region and ensure that the wildlife is protected and that the exploitation of resources is conducted in a sustainable manner.

  5. Arctic Technology Evaluation 2014 Oil-in-Ice Demonstration Report

    Science.gov (United States)

    2015-03-01

    USCGC Healy and evaluated their performance in the cold weather environment as part of Arctic Shield. Based on lessons learned in 2013, the RDC...servicing. Additional bottles were provided for cold weather . Figure 3. Aerostat and LRS (left) and aerostat deployed (right). Arctic Technology...long durations through all weather conditions; and communicate real-time data from the surface of the ocean. The model used in Arctic Shield 2014 was

  6. Arctic glacier movement monitoring with GPS method on 2005

    Institute of Scientific and Technical Information of China (English)

    Ai Songtao; E Dongchen; Yan Ming; Ren Jiawen

    2006-01-01

    During the 2005 Arctic Yellow River Station expedition, the research on monitoring the movement and mass balance of two glaciers around Ny-Alesund,Station expedition were conducted. This paper analyzes the feasibility and advantage in using GPS method to monitor the Arctic glaciers'movement, estimates the precision of first time measured GPS data and discusses the relevant problems in surveying on the Arctic Glaciers with GPS.

  7. Fundamental differences between Arctic and Antarctic ozone depletion

    OpenAIRE

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J.; Min, Flora

    2014-01-01

    Fundamental differences in observed ozone depletion between the Arctic and the Antarctic are shown, clarifying distinctions between both average and extreme ozone decreases in the two hemispheres. Balloon-borne and satellite measurements in the heart of the ozone layer near 18−24 km altitude show that extreme ozone decreases often observed in the Antarctic ozone hole region have not yet been measured in the Arctic in any year, including the unusually cold Arctic spring of 2011. The data provi...

  8. Selling Energy to China: Chinese Energy Politics in the Arctic

    OpenAIRE

    Nguyen, Ly Kieu Le

    2015-01-01

    Abstract Until recently, the Arctic including the Arctic Ocean was only mentioned in the context of global warming. However, global warming has led to a thawing of ice that unveiled great findings of natural resources. The Arctic is now in the middle of a rapid environmental, geopolitical and economic transformation. The planting of the Russian flag by Russian researchers in 2007 on the bottom of the Artic Ocean triggered an overwhelming attention from other actors and states outside the regi...

  9. Impact of declining Arctic sea ice on winter snowfall

    OpenAIRE

    Liu, Jiping; Curry, Judith A.; Wang, Huijun; Song, Mirong; Radley M. Horton

    2012-01-01

    While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic oscillation. However, the atmospheric circulation change linked to the reduction of sea ice shows mu...

  10. Possibilities and prospects of tourism development in the Russian Arctic

    OpenAIRE

    Lubov Larchenko

    2014-01-01

    Abstract. The article deals with necessity and possibility of tourism industry development as the leading sector of territorial specialization of Arctic regions. The problems are considered and strategic directions are defined for the formation and development of the tourism industry in the Arctic regions of Russia. Analysis of foreign experience in tourism development in the Arctic Regions allows to claim that it could be a powerful instrument in the economic development of Russia's Far Nort...

  11. The emergence of surface-based Arctic amplification

    Directory of Open Access Journals (Sweden)

    M. C. Serreze

    2008-07-01

    Full Text Available Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from the NCEP/NCAR reanalysis suggest emergence of surface-based Arctic amplification in the last decade.

  12. SWIFT Observations in the Arctic Sea State DRI

    Science.gov (United States)

    2015-09-30

    OBJECTIVES The objectives are to: develop a sea state climatology for the Arctic Ocean , improve wave forecasting in the presence of sea ice , improve...theory of wave attenuation/scattering in the sea ice cover , apply wave– ice interactions directly in integrated arctic system models, and understand...heat and mass fluxes in the air–sea– ice system. APPROACH The technical approach is to measure waves, winds, and turbulence in the Arctic Ocean

  13. The emergence of surface-based Arctic amplification

    OpenAIRE

    SERREZE, M. C.; A. P. Barrett; J. C. Stroeve; Kindig, D. N.; Holland, M. M.

    2009-01-01

    Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from both the NCEP/NCAR and JRA-25 reanalyses point to emergence of surface-based Arctic amplification in the last decade.

  14. Covering Kiruna : a natural experiment in Arctic awareness.

    OpenAIRE

    2014-01-01

    At a time when the Arctic is attracting increasing international attention and a variety of actors are positioning themselves in anticipation of future developments, news reporters across the world face the challenge of explaining why the Arctic is relevant to the lives and realities of audiences, some of whom are far from the region itself. This challenge was felt particularly profoundly in May 2013, when events and controversies surrounding the Kiruna Arctic Council meeting tasked journalis...

  15. Changes in the Arctic: Background and Issues for Congress

    Science.gov (United States)

    2014-02-14

    and tourism (cruise ships) in the Arctic increase the risk of pollution in the region. Cleaning up oil spills in ice-covered waters will be more...resources, and expanded fishing and tourism (Figure 3). More broadly, physical changes in the Arctic include warming ocean, soil, and air temperatures...Alaska, and the Gulf of Mexico that had been in place since 1982 had not been restored in 2009 appropriations measures. Changes in the Arctic

  16. RADARSAT-1 Background Mission Monitoring of the Arctic

    Science.gov (United States)

    2005-07-25

    coverage of the Arctic would result into valuable temporal records of a part of the world that is particularly sensitive to global climate change...used to define the boundary: The Arctic Circle, a climatic marker, or a vegetational marker. The Arctic Circle is simply the area of mid-night sun...boundary, delineated by the treeline , or the boundary between the Tundra and the (Boreal) forest alone is not appropriate as it is subject to

  17. Spatial Distribution of Methanesulphonic Acid in the Arctic Aerosol Collected during the Chinese Arctic Research Expedition

    Directory of Open Access Journals (Sweden)

    Peipei Ye

    2015-05-01

    Full Text Available Methanesulphonic acid (MSA, mainly derived from marine biogenic emissions has been frequently used to estimate the marine biogenic contribution. However, there are few reports on MSA over the Arctic Ocean, especially the central Arctic Ocean. Here, we analyzed MSA in aerosol samples collected over the ocean and seas during the Chinese Arctic Research Expedition (CHINARE 2012 using ion chromatography. The aerosol MSA concentrations over the Arctic Ocean varied considerably and ranged from non-detectable (ND to 229 ng/m3, with an average of 27 ± 54 ng/m3 (median: 10 ng/m3. We found the distribution of aerosol MSA exhibited an obvious regional variation, which was affected by biotic and abiotic factors. High values were generally observed in the Norwegian Sea; this phenomenon was attributed to high rates of phytoplankton primary productivity and dimethylsulfide (DMS fluxes in this region. Concentrations over the pack ice region in the central Arctic Ocean were generally lower than over the open waters at the ice edge in the Chukchi Sea. This difference was the mainly caused by sea ice. In addition, we found that higher MSA concentrations were associated with warmer sea surface temperature (SST.

  18. Spatial distribution of aquatic marine fungi across the western Arctic and sub-arctic.

    Science.gov (United States)

    Hassett, Brandon T; Ducluzeau, Anne-Lise L; Collins, Roy E; Gradinger, Rolf

    2017-02-01

    Fungi are important parasites of primary producers and nutrient cyclers in aquatic ecosystems. In the Pacific-Arctic domain, fungal parasitism is linked to light intensities and algal stress that can elevate disease incidence on algae and reduce diatom concentrations. Fungi are vastly understudied in the marine realm and knowledge of their function is constrained by the current understanding of fungal distribution and drivers on global scales. To investigate the spatial distribution of fungi in the western Arctic and sub-Arctic, we used high throughput methods to sequence 18S rRNA, cloned and sequenced 28S rRNA and microscopically counted chytrid-infected diatoms. We identified a broad distribution of fungal taxa predominated by Chytridiomycota and Dikarya. Phylogenetic analysis of our Chytridiomycota clones placed Arctic marine fungi sister to the order Lobulomycetales. This clade of fungi predominated in fungal communities under ice with low snowpack. Microscopic examination of fixed seawater and sea ice samples revealed chytrids parasitizing diatoms collected across the Arctic that notably infected 25% of a single diatom species in the Bering Sea. The Pezizomycotina comprised > 95% of eukaryotic sequence reads in Greenland, providing preliminary evidence for osmotrophs being a substitute for algae as the base of food webs. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. PMEL EcoFOCI Early Arctic Data, 1986-1991

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific Marine Environmental Laboratory (PMEL) Fisheries-Oceanography Cooperative Investigations (FOCI) Early Arctic Data, 1987 - 1991

  20. Arctic air pollution: Challenges and opportunities for the next decade

    Directory of Open Access Journals (Sweden)

    S.R. Arnold

    2016-05-01

    Full Text Available Abstract The Arctic is a sentinel of global change. This region is influenced by multiple physical and socio-economic drivers and feedbacks, impacting both the natural and human environment. Air pollution is one such driver that impacts Arctic climate change, ecosystems and health but significant uncertainties still surround quantification of these effects. Arctic air pollution includes harmful trace gases (e.g. tropospheric ozone and particles (e.g. black carbon, sulphate and toxic substances (e.g. polycyclic aromatic hydrocarbons that can be transported to the Arctic from emission sources located far outside the region, or emitted within the Arctic from activities including shipping, power production, and other industrial activities. This paper qualitatively summarizes the complex science issues motivating the creation of a new international initiative, PACES (air Pollution in the Arctic: Climate, Environment and Societies. Approaches for coordinated, international and interdisciplinary research on this topic are described with the goal to improve predictive capability via new understanding about sources, processes, feedbacks and impacts of Arctic air pollution. Overarching research actions are outlined, in which we describe our recommendations for 1 the development of trans-disciplinary approaches combining social and economic research with investigation of the chemical and physical aspects of Arctic air pollution; 2 increasing the quality and quantity of observations in the Arctic using long-term monitoring and intensive field studies, both at the surface and throughout the troposphere; and 3 developing improved predictive capability across a range of spatial and temporal scales.

  1. Arctic biodiversity trends 2010: selected indicators of change

    National Research Council Canada - National Science Library

    2010-01-01

    In 2008, the United Nations Environment Programme (UNEP) passed a resolution expressing 'extreme concern' over the impacts of climate change on Arctic indigenous peoples, other communities and biodiversity...

  2. China in the Arctic: interests, actions and challenges

    OpenAIRE

    2014-01-01

    This article gives an overview of China’s interest in and approach to the Arctic region. The following questions are raised: 1.Why is China getting involved in the Arctic, 2. How is China’s engagement in the Arctic playing out? 3, What are the most important issues that need to be solved in order for China to increase its relevance and importance as a political actor and partner in the Arctic. In applying a rationalist approach when answering the research questions, I identify how China in th...

  3. Extreme Arctic cyclones in CMIP5 historical simulations

    National Research Council Canada - National Science Library

    Vavrus, Stephen J

    2013-01-01

    .... This study addresses whether such powerful storms are an emerging expression of anthropogenic climate change by investigating simulated extreme Arctic cyclones during the historical period (1850–2005...

  4. On the atmospheric response experiment to a Blue Arctic Ocean

    Science.gov (United States)

    Nakamura, Tetsu; Yamazaki, Koji; Honda, Meiji; Ukita, Jinro; Jaiser, Ralf; Handorf, Dörthe; Dethloff, Klaus

    2016-10-01

    We demonstrated atmospheric responses to a reduction in Arctic sea ice via simulations in which Arctic sea ice decreased stepwise from the present-day range to an ice-free range. In all cases, the tropospheric response exhibited a negative Arctic Oscillation (AO)-like pattern. An intensification of the climatological planetary-scale wave due to the present-day sea ice reduction on the Atlantic side of the Arctic Ocean induced stratospheric polar vortex weakening and the subsequent negative AO. Conversely, strong Arctic warming due to ice-free conditions across the entire Arctic Ocean induced a weakening of the tropospheric westerlies corresponding to a negative AO without troposphere-stratosphere coupling, for which the planetary-scale wave response to a surface heat source extending to the Pacific side of the Arctic Ocean was responsible. Because the resultant negative AO-like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification.

  5. How predictable is a summer-ice free Arctic?

    Science.gov (United States)

    Jahn, Alexandra

    2016-04-01

    There is large interest from different stakeholders in when we will first see a summer ice-free Arctic Ocean. However, while the CMIP5 models agree that we will see a further decline of the Arctic sea ice cover over the 21st century, their projections of when an ice-free Arctic will occur has a range of over 100 years for even the strongest forcing scenario, the RCP8.5. A large part of this uncertainty stems from model biases in the simulation of Arctic sea ice in some models. But apart from this bias, how predictable is the Arctic sea ice extent and the timing of the first ice-free Arctic summer in general? Using the Community Earth System Model (CESM) large ensemble with 40+ members for RCP8.5 and the CESM medium ensemble with 15 members for RCP4.5, we will show that internal variability leads to a range of ~20 years for predictions of threshold crossing of Arctic sea ice, limiting the long-term predictability of when an ice-free Arctic Ocean can first be expected. A detailed analysis of the trajectories of the individual ensemble members will reveal whether there are features of the climate system that allow an improvement of this predictability as we get closer to a summer ice-free Arctic.

  6. Identifying Priorities for International Arctic Research and Policy

    Science.gov (United States)

    Rachold, V.; Hik, D.; Barr, S.

    2015-12-01

    The International Arctic Science Committee (IASC) is a non-governmental, international scientific organization, founded in 1990 by representatives of national scientific organizations of the eight Arctic countries - Canada, Denmark, Finland, Iceland, Norway, Russia (at that time Union of Soviet Socialist Republics), Sweden and the United States of America. Over the past 25 years, IASC has evolved into the leading international science organization of the North and its membership today includes 23 countries involved in all aspects of Arctic research, including 15 non-Arctic countries (Austria, China, the Czech Republic, France, Germany, India, Italy, Japan, the Netherlands, Poland, Portugal, South Korea, Spain, Switzerland and the UK). The Founding Articles committed IASC to pursue a mission of encouraging and facilitating cooperation in all aspects of Arctic research, in all countries engaged in Arctic research and in all areas of the Arctic region. IASC promotes and supports leading-edge multi-disciplinary research in order to foster a greater scientific understanding of the Arctic region and its role in the Earth system. IASC has organized three forward-looking conferences focused on international and interdisciplinary perspectives for advancing Arctic research cooperation and applications of Arctic knowledge. Indeed, the IASC Founding Articles call for IASC to host these conferences periodically in order to "review the status of Arctic science, provide scientific and technical advice, and promote cooperation and links with other national and international organizations." Through its members, including national science organizations and funding agencies from all countries engaged in Arctic research, IASC is uniquely placed to undertake this task. As an accredited observer on the Arctic Council, IASC is also in the position to introduce the outcome of its science planning efforts into the Arctićs main political body and to liaise with the Arctic Council Permanent

  7. The dynamics of human-induced land cover change in miombo ecosystems of southern Africa

    Science.gov (United States)

    Jaiteh, Malanding Sambou

    Understanding human-induced land cover change in the miombo require the consistent, geographically-referenced, data on temporal land cover characteristics as well as biophysical and socioeconomic drivers of land use, the major cause of land cover change. The overall goal of this research to examine the applications of high-resolution satellite remote sensing data in studying the dynamics of human-induced land cover change in the miombo. Specific objectives are to: (1) evaluate the applications of computer-assisted classification of Landsat Thematic Mapper (TM) data for land cover mapping in the miombo and (2) analyze spatial and temporal patterns of landscape change locations in the miombo. Stepwise Thematic Classification, STC (a hybrid supervised-unsupervised classification) procedure for classifying Landsat TM data was developed and tested using Landsat TM data. Classification accuracy results were compared to those from supervised and unsupervised classification. The STC provided the highest classification accuracy i.e., 83.9% correspondence between classified and referenced data compared to 44.2% and 34.5% for unsupervised and supervised classification respectively. Improvements in the classification process can be attributed to thematic stratification of the image data into spectrally homogenous (thematic) groups and step-by-step classification of the groups using supervised or unsupervised classification techniques. Supervised classification failed to classify 18% of the scene evidence that training data used did not adequately represent all of the variability in the data. Application of the procedure in drier miombo produced overall classification accuracy of 63%. This is much lower than that of wetter miombo. The results clearly demonstrate that digital classification of Landsat TM can be successfully implemented in the miombo without intensive fieldwork. Spatial characteristics of land cover change in agricultural and forested landscapes in central Malawi

  8. Meteoric 10Be as a tool to investigate human induced soil fluxes: a conceptual model

    Science.gov (United States)

    Campforts, Benjamin; Govers, Gerard; Vanacker, Veerle; De Vente, Joris; Boix-Fayos, Carolina; Minella, Jean; Baken, Stijn; Smolders, Erik

    2014-05-01

    The use of meteoric 10Be as a tool to understand long term landscape behavior is becoming increasingly popular. Due its high residence time, meteoric 10Be allows in principle to investigate in situ erosion rates over time scales exceeding the period studied with classical approaches such as 137Cs. The use of meteoric 10Be strongly contributes to the traditional interpretation of sedimentary archives which cannot be unequivocally coupled to sediment production and could provide biased information over longer time scales (Sadler, 1981). So far, meteoric 10Be has successfully been used in geochemical fingerprinting of sediments, to date soil profiles, to assess soil residence times and to quantify downslope soil fluxes using accumulated 10Be inventories along a hill slope. However, less attention is given to the potential use of the tracer to directly asses human induced changes in soil fluxes through deforestation, cultivation and reforestation. A good understanding of the processes governing the distribution of meteoric 10Be both within the soil profile and at landscape scale is essential before meteoric 10Be can be successfully applied to assess human impact. We developed a spatially explicit 2D-model (Be2D) in order to gain insight in meteoric 10Be movement along a hillslope that is subject to human disturbance. Be2D integrates both horizontal soil fluxes and vertical meteoric 10Be movement throughout the soil prolife. Horizontal soil fluxes are predicted using (i) well studied geomorphical laws for natural erosion and soil formation as well as (ii) human accelerated water and tillage erosion. Vertical movement of meteoric 10Be throughout the soil profile is implemented by inserting depth dependent retardation calculated using experimentally determined partition coefficients (Kd). The model was applied to different environments such as (i) the Belgian loess belt, characterized by aeolian deposits enriched in inherited meteoric 10Be, (ii) highly degraded and stony

  9. Effects of cellular origin on differentiation of human induced pluripotent stem cell-derived endothelial cells.

    Science.gov (United States)

    Hu, Shijun; Zhao, Ming-Tao; Jahanbani, Fereshteh; Shao, Ning-Yi; Lee, Won Hee; Chen, Haodong; Snyder, Michael P; Wu, Joseph C

    2016-06-02

    Human induced pluripotent stem cells (iPSCs) can be derived from various types of somatic cells by transient overexpression of 4 Yamanaka factors (OCT4, SOX2, C-MYC, and KLF4). Patient-specific iPSC derivatives (e.g., neuronal, cardiac, hepatic, muscular, and endothelial cells [ECs]) hold great promise in drug discovery and regenerative medicine. In this study, we aimed to evaluate whether the cellular origin can affect the differentiation, in vivo behavior, and single-cell gene expression signatures of human iPSC-derived ECs. We derived human iPSCs from 3 types of somatic cells of the same individuals: fibroblasts (FB-iPSCs), ECs (EC-iPSCs), and cardiac progenitor cells (CPC-iPSCs). We then differentiated them into ECs by sequential administration of Activin, BMP4, bFGF, and VEGF. EC-iPSCs at early passage (10 < P < 20) showed higher EC differentiation propensity and gene expression of EC-specific markers (PECAM1 and NOS3) than FB-iPSCs and CPC-iPSCs. In vivo transplanted EC-iPSC-ECs were recovered with a higher percentage of CD31(+) population and expressed higher EC-specific gene expression markers (PECAM1, KDR, and ICAM) as revealed by microfluidic single-cell quantitative PCR (qPCR). In vitro EC-iPSC-ECs maintained a higher CD31(+) population than FB-iPSC-ECs and CPC-iPSC-ECs with long-term culturing and passaging. These results indicate that cellular origin may influence lineage differentiation propensity of human iPSCs; hence, the somatic memory carried by early passage iPSCs should be carefully considered before clinical translation.

  10. Effects of cellular origin on differentiation of human induced pluripotent stem cell–derived endothelial cells

    Science.gov (United States)

    Zhao, Ming-Tao; Jahanbani, Fereshteh; Lee, Won Hee; Snyder, Michael P.

    2016-01-01

    Human induced pluripotent stem cells (iPSCs) can be derived from various types of somatic cells by transient overexpression of 4 Yamanaka factors (OCT4, SOX2, C-MYC, and KLF4). Patient-specific iPSC derivatives (e.g., neuronal, cardiac, hepatic, muscular, and endothelial cells [ECs]) hold great promise in drug discovery and regenerative medicine. In this study, we aimed to evaluate whether the cellular origin can affect the differentiation, in vivo behavior, and single-cell gene expression signatures of human iPSC–derived ECs. We derived human iPSCs from 3 types of somatic cells of the same individuals: fibroblasts (FB-iPSCs), ECs (EC-iPSCs), and cardiac progenitor cells (CPC-iPSCs). We then differentiated them into ECs by sequential administration of Activin, BMP4, bFGF, and VEGF. EC-iPSCs at early passage (10 < P < 20) showed higher EC differentiation propensity and gene expression of EC-specific markers (PECAM1 and NOS3) than FB-iPSCs and CPC-iPSCs. In vivo transplanted EC-iPSC–ECs were recovered with a higher percentage of CD31+ population and expressed higher EC-specific gene expression markers (PECAM1, KDR, and ICAM) as revealed by microfluidic single-cell quantitative PCR (qPCR). In vitro EC-iPSC–ECs maintained a higher CD31+ population than FB-iPSC–ECs and CPC-iPSC–ECs with long-term culturing and passaging. These results indicate that cellular origin may influence lineage differentiation propensity of human iPSCs; hence, the somatic memory carried by early passage iPSCs should be carefully considered before clinical translation. PMID:27398408

  11. Generation of Functional Lentoid Bodies From Human Induced Pluripotent Stem Cells Derived From Urinary Cells.

    Science.gov (United States)

    Fu, Qiuli; Qin, Zhenwei; Jin, Xiuming; Zhang, Lifang; Chen, Zhijian; He, Jiliang; Ji, Junfeng; Yao, Ke

    2017-01-01

    The pathological mechanisms underlying cataract formation remain largely unknown on account of the lack of appropriate in vitro cellular models. The aim of this study is to develop a stable in vitro system for human lens regeneration using pluripotent stem cells. Isolated human urinary cells were infected with four Yamanaka factors to generate urinary human induced pluripotent stem cells (UiPSCs), which were induced to differentiate into lens progenitor cells and lentoid bodies (LBs). The expression of lens-specific markers was examined by real-time PCR, immunostaining, and Western blotting. The structure and magnifying ability of LBs were investigated using transmission electron microscopy and observing the magnification of the letter "X," respectively. We developed a "fried egg" differentiation method to generate functional LBs from UiPSCs. The UiPSC-derived LBs exhibited crystalline lens-like morphology and a transparent structure and expressed lens-specific markers αA-, αB-, β-, and γ-crystallin and MIP. During LB differentiation, the placodal markers SIX1, EYA1, DLX3, PAX6, and the specific early lens markers SOX1, PROX1, FOXE3, αA-, and αB-crystallin were observed at certain time points. Microscopic examination revealed the presence of lens epithelial cells adjacent to the lens capsule as well as both immature and mature fiber-like cells. Optical analysis further demonstrated the magnifying ability (1.7×) of the LBs generated from UiPSCs. Our study provides the first evidence toward generating functional LBs from UiPSCs, thereby establishing an in vitro system that can be used to study human lens development and cataractogenesis and perhaps even be useful for drug screening.

  12. Changes in bird-migration patterns associated with human-induced mortality.

    Science.gov (United States)

    Palacín, Carlos; Alonso, Juan C; Martín, Carlos A; Alonso, Javier A

    2017-02-01

    Many bird populations have recently changed their migratory behavior in response to alterations of the environment. We collected data over 16 years on male Great Bustards (Otis tarda), a species showing a partial migratory pattern (sedentary and migratory birds coexisting in the same breeding groups). We conducted population counts and radio tracked 180 individuals to examine differences in survival rates between migratory and sedentary individuals and evaluate possible effects of these differences on the migratory pattern of the population. Overall, 65% of individuals migrated and 35% did not. The average distance between breeding and postbreeding areas of migrant individuals was 89.9 km, and the longest average movement of sedentary males was 3.8 km. Breeding group and migration distance had no effect on survival. However, mortality of migrants was 2.4 to 3.5 times higher than mortality of sedentary birds. For marked males, collision with power lines was the main cause of death from unnatural causes (37.6% of all deaths), and migratory birds died in collisions with power lines more frequently than sedentary birds (21.3% vs 6.3%). The percentage of sedentary individuals increased from 17% in 1997 to 45% in 2012. These results were consistent with data collected from radio-tracked individuals: The proportion of migratory individuals decreased from 86% in 1997-1999 to 44% in 2006-2010. The observed decrease in the migratory tendency was not related to climatic changes (temperatures did not change over the study period) or improvements in habitat quality (dry cereal farmland area decreased in the main study area). Our findings suggest that human-induced mortality during migration may be an important factor shaping the migration patterns of species inhabiting humanized landscapes.

  13. Generation of Human Induced Pluripotent Stem Cells from Extraembryonic Tissues of Fetuses Affected by Monogenic Diseases.

    Science.gov (United States)

    Spitalieri, Paola; Talarico, Rosa V; Botta, Annalisa; Murdocca, Michela; D'Apice, Maria Rosaria; Orlandi, Augusto; Giardina, Emiliano; Santoro, Massimo; Brancati, Francesco; Novelli, Giuseppe; Sangiuolo, Federica

    2015-08-01

    The generation of human induced pluripotent stem cells (hiPSCs) derived from an autologous extraembryonic fetal source is an innovative personalized regenerative technology that can transform own-self cells into embryonic stem-like ones. These cells are regarded as a promising candidate for cell-based therapy, as well as an ideal target for disease modeling and drug discovery. Thus, hiPSCs enable researchers to undertake studies for treating diseases or for future applications of in utero therapy. We used a polycistronic lentiviral vector (hSTEMCCA-loxP) encoding OCT4, SOX2, KLF4, and cMYC genes and containing loxP sites, excisible by Cre recombinase, to reprogram patient-specific fetal cells derived from prenatal diagnosis for several genetic disorders, such as myotonic dystrophy type 1 (DM1), β-thalassemia (β-Thal), lymphedema-distichiasis syndrome (LDS), spinal muscular atrophy (SMA), cystic fibrosis (CF), as well as from wild-type (WT) fetal cells. Because cell types tested to create hiPSCs influence both the reprogramming process efficiency and the kinetics, we used chorionic villus (CV) and amniotic fluid (AF) cells, demonstrating how they represent an ideal cell resource for a more efficient generation of hiPSCs. The successful reprogramming of both CV and AF cells into hiPSCs was confirmed by specific morphological, molecular, and immunocytochemical markers and also by their teratogenic potential when inoculated in vivo. We further demonstrated the stability of reprogrammed cells over 10 and more passages and their capability to differentiate into the three embryonic germ layers, as well as into neural cells. These data suggest that hiPSCs-CV/AF can be considered a valid cellular model to accomplish pathogenesis studies and therapeutic applications.

  14. Degradation of amyloid beta by human induced pluripotent stem cell-derived macrophages expressing Neprilysin-2

    Directory of Open Access Journals (Sweden)

    Koutaro Takamatsu

    2014-11-01

    Full Text Available The purpose of this study was to evaluate the therapeutic potential of human induced pluripotent stem (iPS cell-derived macrophage-like cells for Alzheimer's disease (AD. In previous studies, we established the technology to generate macrophage-like myeloid lineage cells with proliferating capacity from human iPS cells, and we designated the cells iPS-ML. iPS-ML reduced the level of Aβ added into the culture medium, and the culture supernatant of iPS-ML alleviated the neurotoxicity of Aβ. We generated iPS-ML expressing the Fc-receptor-fused form of a single chain antibody specific to Aβ. In addition, we made iPS-ML expressing Neprilysin-2 (NEP2, which is a protease with Aβ-degrading activity. In vitro, expression of NEP2 but not anti-Aβ scFv enhanced the effect to reduce the level of soluble Aβ oligomer in the culture medium and to alleviate the neurotoxicity of Aβ. To analyze the effect of iPS-ML expressing NEP2 (iPS-ML/NEP2 in vivo, we intracerebrally administered the iPS-ML/NEP2 to 5XFAD mice, which is a mouse model of AD. We observed significant reduction in the level of Aβ in the brain interstitial fluid following administration of iPS-ML/NEP2. These results suggested that iPS-ML/NEP2 may be a potential therapeutic agent in the treatment of AD.

  15. A direct pedestrian-structure interaction model to characterize the human induced vibrations on slender footbridges

    Directory of Open Access Journals (Sweden)

    Jiménez-Alonso, J. F.

    2014-12-01

    Full Text Available Although the scientific community had knowledge of the human induced vibration problems in structures since the end of the 19th century, it was not until the occurrence of the vibration phenomenon happened in the Millennium Bridge (London, 2000 that the importance of the problem revealed and a higher level of attention devoted. Despite the large advances achieved in the determination of the human-structure interaction force, one of the main deficiencies of the existing models is the exclusion of the effect of changes in the footbridge dynamic properties due to the presence of pedestrians. In this paper, the formulation of a human-structure interaction model, addresses these limitations, is carried out and its reliability is verified from previously published experimental results.Aunque la comunidad científica tenía conocimiento de los problemas vibratorios inducidos por peatones en estructuras desde finales del siglo xix, no fue hasta la ocurrencia de los eventos vibratorios acontecidos en la pasarela del Milenio (Londres, 2000, cuando la importancia del problema se puso de manifiesto y se le comenzó a dedicar un mayor nivel de atención. A pesar de los grandes avances alcanzados en la caracterización de la fuerza de interacción peatón-estructura una de las principales deficiencias de los modelos existentes es la exclusión del cambio en las propiedades dinámicas de la pasarela por la presencia de peatones. En este artículo, se presenta la formulación de un modelo de interacción peatón-estructura que intenta dar respuesta a dichas limitaciones, y su validación a partir de resultados experimentales previamente publicados por otros autores.

  16. Efficient production of trophoblast lineage cells from human induced pluripotent stem cells.

    Science.gov (United States)

    Kojima, Junya; Fukuda, Atsushi; Taira, Hayato; Kawasaki, Tomoyuki; Ito, Hiroe; Kuji, Naoaki; Isaka, Keiichi; Umezawa, Akihiro; Akutsu, Hidenori

    2017-03-13

    Human induced pluripotent stem cells (hiPSCs) are potentially useful in both clinical applications and basic biological research. hiPSCs can differentiate into extra-embryonic cells in the presence of BMP4. However, the differentiation potential of hiPSCs can be affected by culture conditions or genetic variation. In this study, we investigated the effect of various BMP4 concentrations on the expression states of trophoblast markers and the optimal conditions for trophoblast induction. A high-fidelity gene expression assay using hiPSC lines showed that the expression levels of various trophoblast marker genes, such as KRT7, GCM1, CGB, and HLA-G, were upregulated by BMP4 in a dose-dependent manner in all types of hiPSCs used in this study. Treatment with high doses of BMP4 for prolonged periods increased the ratio of cells with trophoblast markers irrespective of the presence of bFGF. We found that the expression states of major pluripotency- and differentiation-related protein-coding genes in BMP4-treated cells depended on culture conditions rather than donor cell types. However, miRNA expression states were affected by donor cell types rather than BMP4 dose. Furthermore, the effect of the presence of bFGF on differentiation potential of KRT7-positive cells differed among iPSC types. Mechanistically, chromatin states around KRT7 promoter regions were comparable among the iPSC types used in this study, indicating that hiPSC chromatin state at these regions is not a parameter for cytotrophoblast differentiation potential. In conclusion, the optimal conditions for trophoblast differentiation from hiPSCs differ according to parental cell line.Laboratory Investigation advance online publication, 13 March 2017; doi:10.1038/labinvest.2016.159.

  17. Functional analysis of carboxylesterase in human induced pluripotent stem cell-derived enterocytes.

    Science.gov (United States)

    Kabeya, Tomoki; Matsumura, Wakana; Iwao, Takahiro; Hosokawa, Masakiyo; Matsunaga, Tamihide

    2017-04-22

    Human carboxylesterase (CES) is a key esterase involved in the metabolism and biotransformation of drugs. Hydrolysis activity in the human small intestine is predominantly mediated by CES2A1 rather than CES1A. In drug development studies, Caco-2 cells are commonly used as a model to predict drug absorption in the human small intestine. However, the expression patterns of CES2A1 and CES1A in Caco-2 cells differ from those in the human small intestine. There are also species-specific differences in CES expression patterns between human and experimental animals. Furthermore, it is difficult to obtain primary human intestinal epithelial cells. Therefore, there is currently no system that can precisely predict features of drug absorption, such as CES-mediated metabolism, in the human intestine. To develop a novel system to evaluate intestinal pharmacokinetics, we analyzed CES expression and function in human induced pluripotent stem (iPS) cell-derived enterocytes. CES2A1 mRNA and protein levels in human iPS cell-derived enterocytes were comparable to Caco-2 cells, whereas CES1A levels were lower in human iPS cell-derived enterocytes compared with Caco-2 cells. p-nitrophenyl acetate hydrolysis in human iPS cell-derived enterocytes was significantly inhibited by the CES2A1-specific inhibitor telmisartan. Hydrolysis levels of the CES2A1-specific substrate aspirin were similar in human iPS cell-derived enterocytes and Caco-2 cells, whereas hydrolysis of the CES1A-specific substrate monoethylglycylxylidine was observed in Caco-2 cells but not in human iPS cell-derived enterocytes. These findings demonstrated that the expression and activity of CES isozymes in human iPS cell-derived enterocytes are more similar to the human small intestine compared with Caco-2 cells.

  18. Differences in the microrheology of human embryonic stem cells and human induced pluripotent stem cells.

    Science.gov (United States)

    Daniels, Brian R; Hale, Christopher M; Khatau, Shyam B; Kusuma, Sravanti; Dobrowsky, Terrence M; Gerecht, Sharon; Wirtz, Denis

    2010-12-01

    Embryonic and adult fibroblasts can be returned to pluripotency by the expression of reprogramming genes. Multiple lines of evidence suggest that these human induced pluripotent stem (hiPS) cells and human embryonic stem (hES) cells are behaviorally, karyotypically, and morphologically similar. Here we sought to determine whether the physical properties of hiPS cells, including their micromechanical properties, are different from those of hES cells. To this end, we use the method of particle tracking microrheology to compare the viscoelastic properties of the cytoplasm of hES cells, hiPS cells, and the terminally differentiated parental human fibroblasts from which our hiPS cells are derived. Our results indicate that although the cytoplasm of parental fibroblasts is both viscous and elastic, the cytoplasm of hiPS cells does not exhibit any measurable elasticity and is purely viscous over a wide range of timescales. The viscous phenotype of hiPS cells is recapitulated in parental cells with disassembled actin filament network. The cytoplasm of hES cells is predominantly viscous but contains subcellular regions that are also elastic. This study supports the hypothesis that intracellular elasticity correlates with the degree of cellular differentiation and reveals significant differences in the mechanical properties of hiPS cells and hES cells. Because mechanical stimuli have been shown to mediate the precise fate of differentiating stem cells, our results support the concept that stem cell "softness" is a key feature of force-mediated differentiation of stem cells and suggest there may be subtle functional differences between force-mediated differentiation of hiPS cells and hES cells.

  19. Generation of red blood cells from human induced pluripotent stem cells.

    Science.gov (United States)

    Dias, Jessica; Gumenyuk, Marina; Kang, HyunJun; Vodyanik, Maxim; Yu, Junying; Thomson, James A; Slukvin, Igor I

    2011-09-01

    Differentiation of human induced pluripotent stem cells (hiPSCs) and embryonic stem cells (hESCs) into the erythroid lineage of cells offers a novel opportunity to study erythroid development, regulation of globin switching, drug testing, and modeling of red blood cell (RBC) diseases in vitro. Here we describe an approach for the efficient generation of RBCs from hiPSC/hESCs using an OP9 coculture system to induce hematopoietic differentiation followed by selective expansion of erythroid cells in serum-free media with erythropoiesis-supporting cytokines. We showed that fibroblast-derived transgenic hiPSCs generated using lentivirus-based vectors and transgene-free hiPSCs generated using episomal vectors can be differentiated into RBCs with an efficiency similar to that of H1 hESCs. Erythroid cultures established with this approach consisted of an essentially pure population of CD235a(+)CD45(-) leukocyte-free RBCs with robust expansion potential and long life span (up to 90 days). Similar to hESCs, hiPSC-derived RBCs expressed predominately fetal γ and embryonic ɛ globins, indicating complete reprogramming of β-globin locus following transition of fibroblasts to the pluripotent state. Although β-globin expression was detected in hiPSC/hESC-derived erythroid cells, its expression was substantially lower than the embryonic and fetal globins. Overall, these results demonstrate the feasibility of large-scale production of erythroid cells from fibroblast-derived hiPSCs, as has been described for hESCs. Since RBCs generated from transgene-free hiPSCs lack genomic integration and background expression of reprogramming genes, they would be a preferable cell source for modeling of diseases and for gene function studies.

  20. Generation of functionally competent and durable engineered blood vessels from human induced pluripotent stem cells.

    Science.gov (United States)

    Samuel, Rekha; Daheron, Laurence; Liao, Shan; Vardam, Trupti; Kamoun, Walid S; Batista, Ana; Buecker, Christa; Schäfer, Richard; Han, Xiaoxing; Au, Patrick; Scadden, David T; Duda, Dan G; Fukumura, Dai; Jain, Rakesh K

    2013-07-30

    Efficient generation of competent vasculogenic cells is a critical challenge of human induced pluripotent stem (hiPS) cell-based regenerative medicine. Biologically relevant systems to assess functionality of the engineered vessels in vivo are equally important for such development. Here, we report a unique approach for the derivation of endothelial precursor cells from hiPS cells using a triple combination of selection markers--CD34, neuropilin 1, and human kinase insert domain-containing receptor--and an efficient 2D culture system for hiPS cell-derived endothelial precursor cell expansion. With these methods, we successfully generated endothelial cells (ECs) from hiPS cells obtained from healthy donors and formed stable functional blood vessels in vivo, lasting for 280 d in mice. In addition, we developed an approach to generate mesenchymal precursor cells (MPCs) from hiPS cells in parallel. Moreover, we successfully generated functional blood vessels in vivo using these ECs and MPCs derived from the same hiPS cell line. These data provide proof of the principle that autologous hiPS cell-derived vascular precursors can be used for in vivo applications, once safety and immunological issues of hiPS-based cellular therapy have been resolved. Additionally, the durability of hiPS-derived blood vessels in vivo demonstrates a potential translation of this approach in long-term vascularization for tissue engineering and treatment of vascular diseases. Of note, we have also successfully generated ECs and MPCs from type 1 diabetic patient-derived hiPS cell lines and use them to generate blood vessels in vivo, which is an important milestone toward clinical translation of this approach.

  1. Identification of unsafe human induced pluripotent stem cell lines using a robust surrogate assay for pluripotency.

    Science.gov (United States)

    Polanco, Juan Carlos; Ho, Mirabelle S H; Wang, Bei; Zhou, Qi; Wolvetang, Ernst; Mason, Elizabeth; Wells, Christine A; Kolle, Gabriel; Grimmond, Sean M; Bertoncello, Ivan; O'Brien, Carmel; Laslett, Andrew L

    2013-08-01

    Human induced pluripotent stem cells (hiPSC) have the potential to generate healthy cells and tissues for the study and medical treatment of a large number of diseases. The utility of putative hiPSC-based therapies is constrained by a lack of robust quality-control assays that address the stability of the cells or their capacity to form teratomas after differentiation. Here we report that virally derived hiPSC, but not human embryonic stem cells (hESC) or hiPSC derived using episomal nonintegrating vectors, exhibit a propensity to revert to a pluripotent phenotype following differentiation. This instability was revealed using our published method to identify pluripotent cells undergoing very early-stage differentiation in standard hESC cultures, by fluorescence activated cell sorting (FACS) based on expression of the cell surface markers TG30 (CD9) and GCTM-2. Differentiated cells cultured post-FACS fractionation from virally derived hiPSC lines reacquired immunoreactivity to TG30 (CD9) and GCTM-2, formed stem cell-like colonies, and re-expressed canonical pluripotency markers. Furthermore, differentiated cells from pluripotency-reverting hiPSC lines generated teratomas in immunocompromised mice, raising concerns about their safety in downstream applications. In contrast, differentiated cell populations from hESC and episomally derived hiPSC did not show any of these abnormalities. Our assays may be used to identify "unsafe" hiPSC cell lines and this information should be considered when selecting hiPSC lines for clinical use and indicate that experiments using these "unsafe" hiPSC lines should be interpreted carefully.

  2. Systematic evaluation of markers used for the identification of human induced pluripotent stem cells

    Science.gov (United States)

    Bharathan, Sumitha Prameela; Manian, Kannan Vrindavan; Aalam, Syed Mohammed Musheer; Palani, Dhavapriya; Deshpande, Prashant Ajit; Pratheesh, Mankuzhy Damodaran; Srivastava, Alok

    2017-01-01

    ABSTRACT Low efficiency of somatic cell reprogramming and heterogeneity among human induced pluripotent stem cells (hiPSCs) demand extensive characterization of isolated clones before their use in downstream applications. By monitoring human fibroblasts undergoing reprogramming for their morphological changes and expression of fibroblast (CD13), pluripotency markers (SSEA-4 and TRA-1-60) and a retrovirally expressed red fluorescent protein (RV-RFP), we compared the efficiency of these features to identify bona fide hiPSC colonies. The co-expression kinetics of fibroblast and pluripotency markers in the cells being reprogrammed and the emerging colonies revealed the heterogeneity within SSEA-4+ and TRA-1-60+ cells, and the inadequacy of these commonly used pluripotency markers for the identification of bona fide hiPSC colonies. The characteristic morphological changes in the emerging hiPSC colonies derived from fibroblasts expressing RV-RFP showed a good correlation between hiPSC morphology acquisition and silencing of RV-RFP and facilitated the easy identification of hiPSCs. The kinetics of retroviral silencing and pluripotency marker expression in emerging colonies suggested that combining both these markers could demarcate the stages of reprogramming with better precision than with pluripotency markers alone. Our results clearly demonstrate that the pluripotency markers that are routinely analyzed for the characterization of established iPSC colonies are not suitable for the isolation of pluripotent cells in the early stages of reprogramming, and silencing of retrovirally expressed reporter genes helps in the identification of colonies that have attained a pluripotent state and the morphology of human embryonic stem cells (hESCs). PMID:28089995

  3. Erythroid differentiation of human induced pluripotent stem cells is independent of donor cell type of origin.

    Science.gov (United States)

    Dorn, Isabel; Klich, Katharina; Arauzo-Bravo, Marcos J; Radstaak, Martina; Santourlidis, Simeon; Ghanjati, Foued; Radke, Teja F; Psathaki, Olympia E; Hargus, Gunnar; Kramer, Jan; Einhaus, Martin; Kim, Jeong Beom; Kögler, Gesine; Wernet, Peter; Schöler, Hans R; Schlenke, Peter; Zaehres, Holm

    2015-01-01

    Epigenetic memory in induced pluripotent stem cells, which is related to the somatic cell type of origin of the stem cells, might lead to variations in the differentiation capacities of the pluripotent stem cells. In this context, induced pluripotent stem cells from human CD34(+) hematopoietic stem cells might be more suitable for hematopoietic differentiation than the commonly used fibroblast-derived induced pluripotent stem cells. To investigate the influence of an epigenetic memory on the ex vivo expansion of induced pluripotent stem cells into erythroid cells, we compared induced pluripotent stem cells from human neural stem cells and human cord blood-derived CD34(+) hematopoietic stem cells and evaluated their potential for differentiation into hematopoietic progenitor and mature red blood cells. Although genome-wide DNA methylation profiling at all promoter regions demonstrates that the epigenetic memory of induced pluripotent stem cells is influenced by the somatic cell type of origin of the stem cells, we found a similar hematopoietic induction potential and erythroid differentiation pattern of induced pluripotent stem cells of different somatic cell origin. All human induced pluripotent stem cell lines showed terminal maturation into normoblasts and enucleated reticulocytes, producing predominantly fetal hemoglobin. Differences were only observed in the growth rate of erythroid cells, which was slightly higher in the induced pluripotent stem cells derived from CD34(+) hematopoietic stem cells. More detailed methylation analysis of the hematopoietic and erythroid promoters identified similar CpG methylation levels in the induced pluripotent stem cell lines derived from CD34(+) cells and those derived from neural stem cells, which confirms their comparable erythroid differentiation potential.

  4. Efficient generation of functional dopaminergic neurons from human induced pluripotent stem cells under defined conditions.

    Science.gov (United States)

    Swistowski, Andrzej; Peng, Jun; Liu, Qiuyue; Mali, Prashant; Rao, Mahendra S; Cheng, Linzhao; Zeng, Xianmin

    2010-10-01

    Human induced pluripotent stem cells (iPSCs) reprogrammed from somatic cells represent a promising unlimited cell source for generating patient-specific cells for biomedical research and personalized medicine. As a first step, critical to clinical applications, we attempted to develop defined culture conditions to expand and differentiate human iPSCs into functional progeny such as dopaminergic neurons for treating or modeling Parkinson's disease (PD). We used a completely defined (xeno-free) system that we previously developed for efficient generation of authentic dopaminergic neurons from human embryonic stem cells (hESCs), and applied it to iPSCs. First, we adapted two human iPSC lines derived from different somatic cell types for the defined expansion medium and showed that the iPSCs grew similarly as hESCs in the same medium regarding pluripotency and genomic stability. Second, by using these two independent adapted iPSC lines, we showed that the process of differentiation into committed neural stem cells (NSCs) and subsequently into dopaminergic neurons was also similar to hESCs. Importantly, iPSC-derived dopaminergic neurons were functional as they survived and improved behavioral deficits in 6-hydroxydopamine-leasioned rats after transplantation. In addition, iPSC-derived NSCs and neurons could be efficiently transduced by a baculoviral vector delivering episomal DNA for future gene function study and disease modeling using iPSCs. We also performed genome-wide microarray comparisons between iPSCs and hESCs, and we derived NSC and dopaminergic neurons. Our data revealed overall similarity and visible differences at a molecular level. Efficient generation of functional dopaminergic neurons under defined conditions will facilitate research and applications using PD patient-specific iPSCs.

  5. Generation and genetic engineering of human induced pluripotent stem cells using designed zinc finger nucleases.

    Science.gov (United States)

    Ramalingam, Sivaprakash; London, Viktoriya; Kandavelou, Karthikeyan; Cebotaru, Liudmila; Guggino, William; Civin, Curt; Chandrasegaran, Srinivasan

    2013-02-15

    Zinc finger nucleases (ZFNs) have become powerful tools to deliver a targeted double-strand break at a pre-determined chromosomal locus in order to insert an exogenous transgene by homology-directed repair. ZFN-mediated gene targeting was used to generate both single-allele chemokine (C-C motif) receptor 5 (CCR5)-modified human induced pluripotent stem cells (hiPSCs) and biallele CCR5-modified hiPSCs from human lung fibroblasts (IMR90 cells) and human primary cord blood mononuclear cells (CBMNCs) by site-specific insertion of stem cell transcription factor genes flanked by LoxP sites into the endogenous CCR5 locus. The Oct4 and Sox2 reprogramming factors, in combination with valproic acid, induced reprogramming of human lung fibroblasts to form CCR5-modified hiPSCs, while 5 factors, Oct4/Sox2/Klf4/Lin28/Nanog, induced reprogramming of CBMNCs. Subsequent Cre recombinase treatment of the CCR5-modified IMR90 hiPSCs resulted in the removal of the Oct4 and Sox2 transgenes. Further genetic engineering of the single-allele CCR5-modified IMR90 hiPSCs was achieved by site-specific addition of the large CFTR transcription unit to the remaining CCR5 wild-type allele, using CCR5-specific ZFNs and a donor construct containing tdTomato and CFTR transgenes flanked by CCR5 homology arms. CFTR was expressed efficiently from the endogenous CCR5 locus of the CCR5-modified tdTomato/CFTR hiPSCs. These results suggest that it might be feasible to use ZFN-evoked strategies to (1) generate precisely targeted genetically well-defined patient-specific hiPSCs, and (2) then to reshape their function by targeted addition and expression of therapeutic genes from the CCR5 chromosomal locus for autologous cell-based transgene-correction therapy to treat various recessive monogenic human diseases in the future.

  6. What are the Microphysical Properties of Clouds in an Atmosphere without Human-Induced Pollution?

    Science.gov (United States)

    Feichter, J.; O'Donnell, D.

    2009-04-01

    The composition of the atmosphere without any man-made emissions is controlled by biogenic and volcanic emissions and wind-driven particle emissions from the pedosphere and the ocean. Biogenic sources include phytoplankton, emission of volatile organic carbon (VOC) compounds by plants and reduced sulfur emissions from vegetation and soils. Besides mineral dust and biomass burning emissions, organics formed from biogenic VOC was likely the dominating aerosol over continents. The different chemical composition of present-day and past climate aerosol loading might affect the subset of aerosols acting as cloud condensation nuclei and subsequently the microphysical properties of clouds. We will present some exploratory model simulations contrasting the climate system in the absence of human-induced aerosol and VOC emissions with that in the presence of such emissions. In particular, cloud properties will be simulated for present-day emissions and contrasted to a scenario where anthropogenic emissions are switched off. The atmospheric general circulation model ECHAM5 used for this study includes the aerosol model HAM and has been extended by an emission model and a module for secondary organic aerosol (SOA). The updated model treats SOA formed from the anthropogenic precursors toluene, xylene and benzene and from the biogenic precursors isoprene and monoterpenes. SOA-specific modelled processes are precursor emissions, gas-phase formation of SOA and gas-aerosol phase partitioning of SOA. Aerosol microphysical and sink processes (dry and wet removal) are treated with minor modifications to the existing model. The VOC emissions from plants are calculated dependent on surface temperature and photosynthetically active radiation flux.

  7. X-chromosome inactivation in Rett Syndrome human induced pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Aaron YL Cheung

    2012-03-01

    Full Text Available Rett Syndrome (RTT is a neurodevelopmental disorder that affects girls due primarily to heterozygous mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MECP2. Random X-chromosome inactivation (XCI results in cellular mosaicism in which some cells express wild-type MECP2 while other cells express mutant MECP2. The generation of patient-specific human induced Pluripotent Stem cells (hiPSCs facilitates the production of RTT-hiPSC-derived neurons in vitro to investigate disease mechanisms and identify novel drug treatments. The generation of RTT-hiPSCs has been reported by many laboratories, however, the XCI status of RTT-hiPSCs has been inconsistent. Some report RTT-hiPSCs retain the inactive X-chromosome (post-XCI of the founder somatic cell allowing isogenic RTT-hiPSCs that express only the wild-type or mutant MECP2 allele to be isolated from the same patient. Post-XCI RTT-hiPSCs-derived neurons retain this allele-specific expression pattern of wild-type or mutant MECP2. Conversely, others report RTT-hiPSCs in which the inactive X-chromosome of the founder somatic cell reactivates (pre-XCI upon reprogramming into RTT-hiPSCs. Pre-XCI RTT-hiPSC-derived neurons exhibit random XCI resulting in cellular mosaicism with respect to wild-type and mutant MECP2 expression. Here we review and attempt to interpret the inconsistencies in XCI status of RTT-hiPSCs generated to date by comparison to other pluripotent systems in vitro and in vivo and the methods used to analyze XCI. Finally, we discuss the relative strengths and weaknesses of post- and pre-XCI hiPSCs in the context of RTT, and other X-linked and autosomal disorders for translational medicine.

  8. Human induced pluripotent stem cell-derived beating cardiac tissues on paper.

    Science.gov (United States)

    Wang, Li; Xu, Cong; Zhu, Yujuan; Yu, Yue; Sun, Ning; Zhang, Xiaoqing; Feng, Ke; Qin, Jianhua

    2015-11-21

    There is a growing interest in using paper as a biomaterial scaffold for cell-based applications. In this study, we made the first attempt to fabricate a paper-based array for the culture, proliferation, and direct differentiation of human induced pluripotent stem cells (hiPSCs) into functional beating cardiac tissues and create "a beating heart on paper." This array was simply constructed by binding a cured multi-well polydimethylsiloxane (PDMS) mold with common, commercially available paper substrates. Three types of paper material (print paper, chromatography paper and nitrocellulose membrane) were tested for adhesion, proliferation and differentiation of human-derived iPSCs. We found that hiPSCs grew well on these paper substrates, presenting a three-dimensional (3D)-like morphology with a pluripotent property. The direct differentiation of human iPSCs into functional cardiac tissues on paper was also achieved using our modified differentiation approach. The cardiac tissue retained its functional activities on the coated print paper and chromatography paper with a beating frequency of 40-70 beats per min for up to three months. Interestingly, human iPSCs could be differentiated into retinal pigment epithelium on nitrocellulose membrane under the conditions of cardiac-specific induction, indicating the potential roles of material properties and mechanical cues that are involved in regulating stem cell differentiation. Taken together, these results suggest that different grades of paper could offer great opportunities as bioactive, low-cost, and 3D in vitro platforms for stem cell-based high-throughput drug testing at the tissue/organ level and for tissue engineering applications.

  9. Air cushion vehicles for arctic operation

    Science.gov (United States)

    Koleser, J.; Lavis, D. R.

    1986-09-01

    Attention is given to the results of the NAVSEA FY85 Surface Ship Concept Formulation Design Study for an initial operational capability year-2000 air cushion vehicle (ACV) suitable for logistics and general search/rescue duties in the Arctic. Two designs were developed during the study; the first utilized an ACV design synthesis math model while the second evolved as a derivative of an existing U.S. production craft. Both are regarded as feasible from an engineering and naval architectural standpoint. Results of performance and cost trade-off studies suggest that, for an Arctic ACV, gas turbines are the preferred power plant choice and an aluminum alloy is the preferred hull structural material choice. The most appropriate skirt height is approximately 12 ft.

  10. Cartopolitics, Geopolitics and Boundaries in the Arctic

    DEFF Research Database (Denmark)

    Strandsbjerg, Jeppe

    2012-01-01

    Critical Border Studies emphasise how distinct political spaces are produced by borders. In this article I suggest that the order of this relationship should be reversed. I argue that space precedes and conditions the manifestation of borders. The argument is based on an understanding of cartogra......Critical Border Studies emphasise how distinct political spaces are produced by borders. In this article I suggest that the order of this relationship should be reversed. I argue that space precedes and conditions the manifestation of borders. The argument is based on an understanding...... in the Arctic, the term cartopolitics captures how the relationship between the United Nations Convention on the Law of the Sea and cartography is shaping the attempts by Arctic states to expand sovereign rights into the sea. The key is the continental shelf and how it is defined in law. In this process...

  11. The effectiveness of the Arctic Council

    Directory of Open Access Journals (Sweden)

    Paula Kankaanpää

    2012-10-01

    Full Text Available Created in 1996, the Arctic Council has now been in operation long enough to justify a systematic effort to assess its effectiveness. To explore this topic, we created a questionnaire and circulated it to a large number of individuals who have participated in the work of the council in one capacity or another or who have followed the work of the council closely. This article analyses the quantitative and the qualitative input of those who responded to the questionnaire. The main conclusions are that: (1 the council has achieved considerable success in identifying emerging issues, framing them for consideration in policy venues and raising their visibility on the policy agenda and (2 changes now occurring in the Arctic will require significant adjustments to maintain the effectiveness of the council during the foreseeable future.

  12. Record Arctic Sea Ice Loss in 2007

    Science.gov (United States)

    2007-01-01

    This image of the Arctic was produced from sea ice observations collected by the Advanced Microwave Scanning Radiometer (AMSR-E) Instrument on NASA's Aqua satellite on September 16, overlaid on the NASA Blue Marble. The image captures ice conditions at the end of the melt season. Sea ice (white, image center) stretches across the Arctic Ocean from Greenland to Russia, but large areas of open water were apparent as well. In addition to record melt, the summer of 2007 brought an ice-free opening though the Northwest Passage that lasted several weeks. The Northeast Passage did not open during the summer of 2007, however, as a substantial tongue of ice remained in place north of the Russian coast. According to the National Snow and Ice Data Center (NSIDC), on September 16, 2007, sea ice extent dropped to 4.13 million square kilometers (1.59 million square miles)--38 percent below average and 24 percent below the 2005 record.

  13. Methane and Root Dynamics in Arctic Soil

    DEFF Research Database (Denmark)

    D'Imperio, Ludovica

    on the global climate. We investigated two aspects of arctic ecosystem dynamics which are not well represented in climatic models: i) soil methane (CH4) oxidation in dry heath tundra and barren soils and ii) root dynamics in wetlands. Field measurements were carried out during the growing season in Disko Island......, West Greenland, and CH4 and root dynamics were assessed in response to experimentally increased winter snow precipitation, summer warming and their interaction to better understand their contribution to the C balance of the Arctic. Our results indicate that both the dry heath and barren soils have...... from wetlands in a future warmer climate. At the wet fen increased winter snow precipitation delayed the onset of the growing season of about a week and reduced the relative fine root production. The use of minirhizotrons improved our understanding of root growth and phenology. Total root number...

  14. Politics of Sustainability in the Arctic

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram; Jakobsen, Uffe; Strandsbjerg, Jeppe

    2017-01-01

    the role of sustainability in political and economic strategies in the Arctic. Sustainability has become a fundamental concept that orders the relationship between the environment (nature) and development (economy), however, in the process rearticulating other concepts such as identity (society). Hence, we......The concept of sustainability has become central in arctic politics. However, there is little agreement on what ‘sustainable’ means. For different actors (governments, indigenous people, NGOs, etc.) the concept implies different sets of opportunities and precautions. Sustainability, therefore......, is a much more fundamental idea to be further elaborated depending on contexts than a definable term with a specific meaning. This paper suggests a set of theoretical questions, which can provide the first steps toward a research agenda on the politics of sustainability. The approach aims to map and analyze...

  15. Eurasian Arctic abyssal waters are warming

    Science.gov (United States)

    Schauer, Ursula; von Appen, Wilken-Jon; Somavilla Cabrillo, Raquel; Behrendt, Axel; Rabe, Benjamin

    2016-04-01

    In the past decades, not only the upper water layers, but also the deepest layers of the Arctic Ocean have been warming. Observations show that the rate of warming varies markedly in the different basins with the fastest warming in the deep Greenland Sea (ca. 0.11°C per decade) and the Eurasian Basin featuring an average rate of ca. 0.01°C per decade. While the warming in the Greenland Sea is attributed to ongoing export of relatively warmer deep waters from the Arctic Ocean in combination with the halt of deep convection, the reason of Eurasian Basin deep warming is less clear. We discuss possible causes such as changes in the abyssal ventilation through slope convection, advection from other basins and/or geothermal heating through various sources.

  16. Dipole anomaly in the Arctic atmosphere and winter Arctic sea ice motion

    Institute of Scientific and Technical Information of China (English)

    WU; Bingyi; ZHANG; Renhe

    2005-01-01

    This paper investigates a previously-ignored atmospheric circulation anomaly-di- pole structure anomaly in the arctic atmosphere, and its relationship with the winter sea ice motion, based on analyses of the International Arctic Buoy Programme Data (1979-1998) and datasets from the National Center for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) for the period of 1960-2002. The dipole structure anomaly is the second-leading mode of EOF of monthly mean SLP north of 70(N during the winter season (Oct.-Mar.), which accounts for 13% of the variance. One of its two anomaly centers is over the Canadian Archipelago; the other is situated over northern Eurasia and the Siberian marginal seas. Due to the dipole structure anomaly's strong meridionality, it becomes an important mechanism to drive both anomalous sea ice export out of the Arctic Basin and cold air outbreaks into the Barents Sea, the Nordic Seas and northern Europe.

  17. Chemical pollution in the Arctic and Sub-Arctic marine ecosystems: an overview of current knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Savinova, T.N.; Gabrielsen, G.W.; Falk-Petersen, S.

    1995-02-01

    This report is part of a research project in the framework of the Norwegian-Russian Environmental Cooperation, which was initiated in 1991 to elucidate the present status of environmental contaminants in the highly sensitive Arctic aquatic ecosystem, with special focus on sea birds. Although these ecosystems are the least polluted areas in the world, they are contaminated. The main pathways of contamination into Arctic and sub-Arctic marine ecosystems are atmospheric transport, ocean currents and rivers and in some areas, dumping and ship accidents. A literature survey reveals: (1) there is a lack of data from several trophic levels, (2) previous data are difficult to compare with recent data because of increased quality requirement, (3) not much has been done to investigate the effects of contaminants on the cellular level, at individual or population levels. 389 refs., 7 figs., 32 tabs.

  18. Arctic Undersea Inspection of Pipelines and Structures.

    Science.gov (United States)

    1983-06-01

    unqualified, but the stress factor is ever present. Sheader (1980), in describing his operational experiences with the one-man MANTIS vehicle likens the stress...induced vibrations and is provided by Applied Dynamics Ltd. under the name of SHRIMP . It i. 4" consists of the injection of a low level swept...Arctic Alaskan Coastal Plain. U.S. Army Corps of Engineers CRREL Special Rept. No. 163. Sheader, P. 1980 A pilot’s experience in operating a MANTIS

  19. Climate-derived tensions in Arctic security.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Strickland, James Hassler

    2008-09-01

    Globally, there is no lack of security threats. Many of them demand priority engagement and there can never be adequate resources to address all threats. In this context, climate is just another aspect of global security and the Arctic just another region. In light of physical and budgetary constraints, new security needs must be integrated and prioritized with existing ones. This discussion approaches the security impacts of climate from that perspective, starting with the broad security picture and establishing how climate may affect it. This method provides a different view from one that starts with climate and projects it, in isolation, as the source of a hypothetical security burden. That said, the Arctic does appear to present high-priority security challenges. Uncertainty in the timing of an ice-free Arctic affects how quickly it will become a security priority. Uncertainty in the emergent extreme and variable weather conditions will determine the difficulty (cost) of maintaining adequate security (order) in the area. The resolution of sovereignty boundaries affects the ability to enforce security measures, and the U.S. will most probably need a military presence to back-up negotiated sovereignty agreements. Without additional global warming, technology already allows the Arctic to become a strategic link in the global supply chain, possibly with northern Russia as its main hub. Additionally, the multinational corporations reaping the economic bounty may affect security tensions more than nation-states themselves. Countries will depend ever more heavily on the global supply chains. China has particular needs to protect its trade flows. In matters of security, nation-state and multinational-corporate interests will become heavily intertwined.

  20. Evaluation of arctic broadband surface radiation measurements

    OpenAIRE

    N. Matsui; C. N. Long; Augustine, J.; D. Halliwell; T. Uttal; Longenecker, D.; O. Nievergall; Wendell, J.; Albee, R.

    2011-01-01

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are...

  1. Evaluation of Arctic broadband surface radiation measurements

    OpenAIRE

    N. Matsui; C. N. Long; Augustine, J.; D. Halliwell; T. Uttal; Longenecker, D.; Niebergall, O.; Wendell, J.; Albee, R.

    2012-01-01

    The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW) and thermal infrared, or longwave (LW), radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that ...

  2. A Compendium of Arctic Environmental Information

    Science.gov (United States)

    1986-03-01

    leave the Arctic Basin by way of the channels of the Canadian Arrtic Archipelago or the Lincoln Sea Drift between EUesmere Island and Greenland...ice dams, and flooding oc- cur. The navigation period for the lower reaches of the rivers is 3-4 months. Freeze-up begins at Tiksi, in Guba Buor...substantially colder waters that are located at the en- trance of Guba Shelekhova and Ostrava lony and between the Cstrov Shanta and northern Sakhalin

  3. Arctic Region Policy: Information Sharing Model Options

    Science.gov (United States)

    2010-09-01

    specializations , meaning that expertise is not blended into a process that focuses on one sector over another. Figure 25 highlights APIP’s ability to...8 Figure 5. 2004 Arctic Maritime Activity (From Treadwell, 2009, p. 48) .............. 10 Figure 6. Explorer Stuck in the Antarctic (From New...been a Titanic situation, such as what happened to the cruise ship EXPLORER in the Antarctic in November 2007 as shown in Figure 6 (Browley & 11

  4. The effectiveness of the Arctic Council

    OpenAIRE

    2012-01-01

    Created in 1996, the Arctic Council has now been in operation long enough to justify a systematic effort to assess its effectiveness. To explore this topic, we created a questionnaire and circulated it to a large number of individuals who have participated in the work of the council in one capacity or another or who have followed the work of the council closely. This article analyses the quantitative and the qualitative input of those who responded to the questionnaire. The main conclusions a...

  5. Low Frequency Attenuation in the Arctic Ocean

    Science.gov (United States)

    2016-06-07

    for the Arctic , however, this term is predominantly determined by scattering loss from the rough ice canopy, and that it is two orders of magnitude...absorption by two orders of magnitude. The most likely mechanism is scattering from the rough ice canopy. Theoretical estimates of the scattering loss ...models of the ice canopy having varying degrees of realism. All theoretical estimates for scattering loss , irrespective of the particular model for the

  6. Quantifying transport into the Arctic lowermost stratosphere

    Directory of Open Access Journals (Sweden)

    A. Werner

    2009-01-01

    Full Text Available In-situ measurements of the long-lived trace gases N2O, CFC-11 (CCl3F, H-1211 (CBrClF2, CH4, O3 and H2O performed in the Arctic winter 2003 on board the high-altitude aircraft M55 Geophysica are presented and used to study transport into the lowermost stratosphere (LMS. Fractions of air in the LMS originating in i the troposphere, ii the extra-vortex stratosphere above 400 K and iii the Arctic vortex above 400 K are determined using a simple mass balance calculation. The analysis exhibits a strong tropospheric influence of 50% or more in the lowest 20 K of the high-latitude LMS. Above this region the LMS is dominated by air masses having descended from above 400 K. Below the Arctic vortex region at potential temperatures above 360 K, air in the LMS is a mixture of extra-vortex stratospheric and vortex air masses. The vortex fraction increases from about 40% at 360 K to 100% at 400 K for equivalent latitudes >70° N. This influence of air masses descending through the bottom of the polar vortex increases over the course of the winter. By the end of winter a significant fraction of 30% vortex air in the LMS is found even at an equivalent latitude of 40° N. Since the chemical and dynamical history of vortex air is distinct from that of mid-latitude stratospheric air masses, this study implies that the composition of the mid- to high-latitude LMS during late winter and spring is significantly influenced by the Arctic vortex.

  7. Canada : oil, gas, and the new Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Huebert, R. [Calgary Univ., AB (Canada). Dept. of Political Science; Calgary Univ., AB (Canada). Centre for Military and Strategic Studies

    2010-07-01

    This presentation provided a broad overview of the geopolitical issues affecting the massive transformation of the Arctic resulting from resource development, globalization, and climate change. Two Arctics are emerging, notably one European and one North American. Oil and gas companies are investing heavily in the North, and there is continued debate over pipelines and projects, but the viability of projects can shift abruptly from technological and political change. Recent examples include the emergence of shale gas, the possibility of the United States becoming a gas exporter, and the Deepwater Horizon disaster. In terms of Maritime jurisdictions and boundaries, a comparison was presented regarding the Canadian and Russian claims to the continental shelf. International cooperation and a commitment to peaceful means can be seen in the Ilulissat Declaration, the acceptance of the United Nations Convention of the Law of the Sea as rules, the scientific cooperation of Canada, the United States, and Denmark, and the recent boundary agreement between Russia and Norway. The positions of the main players in the new geopolitics of the North were outlined, particularly with respect to Russia, the United States, Norway, Denmark, and Canada. Their recent policy statements and developing arctic force capabilities were summarized. Canada's more assertive Arctic policy was outlined in more detail along with the country's base locations and recent security actions in the North. The main issues facing nations with interests in the North will be maritime and aerospace; understanding the new players on the scene; and new technological developments. 10 figs., 5 refs.

  8. Preliminary Design Guide for Arctic Equipment

    Science.gov (United States)

    1989-05-01

    inland areas, such as central on the ships mentioned in the Introduction to Part Greenland , the Canadian Rockies and Siberia. 2 can be attributed to...periods in Greenland . connector contact springs to disengage. Meter In the Arctic, wind affects equipment operation movements may fail completely at low...cables are availa- ing snow and meltwater in the snowpack. If snow ble but are generally quite expensive. However, gets in, it will almost certainly melt

  9. Debating the Arctic during the Ukraine Crisis – Comparing Arctic State Identities and Media Discourses in Canada and Norway

    DEFF Research Database (Denmark)

    Burke, Danita Catherine; Rahbek-Clemmensen, Jon

    2017-01-01

    Previous studies have argued that domestic factors, including each state’s Arctic state identities, may explain why some Western states (e.g. Canada) have been more critical of Russia in the Arctic than others (e.g. Norway). The present study analyses part of the link between Arctic state...... assertive course vis-à-vis Russia. In Norway, the strong economic discourse coloured early debates about the crisis, but after the widening of economic sanctions against Russia in the summer of 2014, territorial discourses played a more important role. The article thus illustrates that Arctic state...

  10. Human-induced pluripotent stem cells from blood cells of healthy donors and patients with acquired blood disorders

    OpenAIRE

    2009-01-01

    Human induced pluripotent stem (iPS) cells derived from somatic cells hold promise to develop novel patient-specific cell therapies and research models for inherited and acquired diseases. We and others previously reprogrammed human adherent cells, such as postnatal fibroblasts to iPS cells, which resemble adherent embryonic stem cells. Here we report derivation of iPS cells from postnatal human blood cells and the potential of these pluripotent cells for disease modeling. Multiple human iPS ...

  11. The Arctic Regional Communications Small SATellite (ARCSAT)

    Science.gov (United States)

    Casas, Joseph; Kress, Martin; Sims, William; Spehn, Stephen; Jaeger, Talbot; Sanders, Devon

    2013-01-01

    Traditional satellite missions are extremely complex and expensive to design, build, test, launch and operate. Consequently many complementary operational, exploration and research satellite missions are being formulated as a growing part of the future space community capabilities using formations of small, distributed, simple to launch and inexpensive highly capable small scale satellites. The Arctic Regional Communications small SATellite (ARCSAT) initiative would launch a Mini-Satellite "Mothership" into Polar or Sun Sync low-earth-orbit (LEO). Once on orbit, the Mothership would perform orbital insertion of four internally stored independently maneuverable nanosatellites, each containing electronically steerable antennas and reconfigurable software-defined radios. Unlike the traditional geostationary larger complex satellite communication systems, this LEO communications system will be comprised of initially a five small satellite formation that can be later incrementally increased in the total number of satellites for additional data coverage. ARCSAT will provide significant enabling capabilities in the Arctic for autonomous voice and data communications relay, Maritime Domain Awareness (MDA), data-extraction from unattended sensors, and terrestrial Search & Rescue (SAR) beacon detection missions throughout the "data starved desert" of the Arctic Region.

  12. Geolocating Russian sources for Arctic black carbon

    Science.gov (United States)

    Cheng, Meng-Dawn

    2014-08-01

    To design and implement an effective emission control strategy for black carbon (BC), the locations and strength of BC sources must be identified. Lack of accurate source information from the Russian Federation has created difficulty for a range of research and policy activities in the Arctic because Russia occupies the largest landmass in the Arctic Circle. A project was initiated to resolve emission sources of BC in the Russian Federation by using the Potential Source Contribution Function (PSCF). It used atmospheric BC data from two Arctic sampling stations at Alert Nunavut, Canada, and Tiksi Bay, Russia. The geographical regions of BC emission sources in Russia were identified and summarized as follows: (1) a region surrounding Moscow, (2) regions in Eurasia stretching along the Ural Mountains from the White Sea to the Black Sea, and (3) a number of scattered areas from western Siberia to the Russian Far East. Particulate potassium ions, non-marine sulfate, and vanadium were used to assist in resolving the source types: forest fire/biomass burning, coal-fired power plant, and oil combustion. Correlating these maps with the BC map helped to resolve source regions of BC emissions and connect them to their corresponding source types. The results imply that a region south of Moscow and another north of the Ural Mountains could be significant BC sources, but none of the grid cells in these regions could be linked to forest fires, oil combustion, or coal-fired power plants based on these three markers.

  13. Stochastic daily modeling of arctic tundra ecosystems

    Science.gov (United States)

    Erler, A.; Epstein, H. E.; Frazier, J.

    2011-12-01

    ArcVeg is a dynamic vegetation model that has simulated interannual variability of production and abundance of arctic tundra plant types in previous studies. In order to address the effects of changing seasonality on tundra plant community composition and productivity, we have uniquely adapted the model to operate on the daily timescale. Each section of the model-weather generation, nitrogen mineralization, and plant growth dynamics-are driven by daily fluctuations in simulated temperature conditions. These simulation dynamics are achieved by calibrating stochastic iterative loops and mathematical functions with raw field data. Air temperature is the fundamental driver in the model, parameterized by climate data collected in the field across numerous arctic tundra sites, and key daily statistics are extracted (mean and standard deviation of temperature for each day of the year). Nitrogen mineralization is calculated as an exponential function from the simulated temperature. The seasonality of plant growth is driven by the availability of nitrogen and constrained by historical patterns and dynamics of the remotely sensed normalized difference vegetation index (NDVI), as they pertain to the seasonal onset of growth. Here we describe the methods used for daily weather generation, nitrogen mineralization, and the daily competition among twelve plant functional types for nitrogen and subsequent growth. This still rather simple approach to vegetation dynamics has the capacity to generate complex relationships between seasonal patterns of temperature and arctic tundra vegetation community structure and function.

  14. Identification of Human-induced Initiating Event in the Low and Shutdown operation by using CESA method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Chan; Kim, Jong Hyun [KEPCO International nuclear Graduate School, Ulsan (Korea, Republic of)

    2014-08-15

    This paper suggests a procedure to identify human-induced initiating events during low and shutdown state in Nuclear Power Plant (NPP). Human-induced initiating events, also called Category B actions in human reliability analysis (HRA), are operator actions that may lead directly to initiating events either by themselves or in combination with equipment failures. Most of conventional probabilistic safety analyses (PSAs) typically assume that the frequency of initiating events also includes the probability of human-induced initiating events. However, some regulatory documents require Category B actions to be specifically analyzed and quantified in the PSA. In addition, a NUREG report also addresses that an explicit modeling of Category B actions could potentially lead to important insights for human performance on safety. However, there is no standard procedure to identify Category B actions which are either recommended by regulations or widely used in the PSA. This paper develops a systematic procedure to identify the Category B actions for the shutdown and low power. The procedure includes several steps to derive operator actions that may lead to initiating events in the low and shutdown stage. Those steps are the selection of initiating events to be analyzed, the selection of systems or components, the screening of unlikely operating actions, and quantification of initiating events. The procedure also suggests the detailed activity of each step such as the information required, screening rules, and output of steps. Finally, the applicability of the suggested approach is also investigated to show its feasibility.

  15. Development of Exhibit on Arctic Climate Change Called The Arctic: A Friend Acting Strangely Exhibition

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, Barbara W.

    2006-04-01

    The exhibition, The Arctic: A Friend Acting Strangely, was developed at the Smithsonian Institution’s National Museum of Natural History (NMNH) as a part of the museum’s Forces of Change exhibit series on global change. It opened to the public in Spring 2006, in conjunction with another Forces of Change exhibit on the Earth’s atmosphere called Change Is in the Air. The exhibit was a 2000 square-foot presentation that explored the forces and consequences of the changing Arctic as documented by scientists and native residents alike. Native peoples of the Arctic have always lived with year-to-year fluctuations in weather and ice conditions. In recent decades, they have witnessed that the climate has become unpredictable, the land and sea unfamiliar. An elder in Arctic Canada recently described the weather as uggianaqtuq —an Inuit word that can suggest strange, unexpected behavior, sometimes described as that of “a friend acting strangely.” Scientists too have been documenting dramatic changes in the Arctic. Air temperatures have warmed over most—though not all—of the Arctic since the 1950s; Arctic precipitation may have increased by as much as 8%; seasonal melting of the Greenland Ice Sheet has increased on average by 16% since 1979; polar-orbiting satellites have measured a 15¬–20% decline in sea ice extent since the 1970s; aircraft reconnaissance and ship observations show a steady decrease in sea ice since the 1950s. In response to this warming, plant distributions have begun to shift and animals are changing their migration routes. Some of these changes may have beneficial effects while others may bring hardship or have costly implications. And, many scientists consider arctic change to be a ‘bell-weather’ for large-scale changes in other regions of the world. The exhibition included text, photos artifacts, hands-on interactives and other exhibitry that illustrated the changes being documented by indigenous people and scientists alike.

  16. Evaluating Arctic warming mechanisms in CMIP5 models

    Science.gov (United States)

    Franzke, Christian L. E.; Lee, Sukyoung; Feldstein, Steven B.

    2016-07-01

    Arctic warming is one of the most striking signals of global warming. The Arctic is one of the fastest warming regions on Earth and constitutes, thus, a good test bed to evaluate the ability of climate models to reproduce the physics and dynamics involved in Arctic warming. Different physical and dynamical mechanisms have been proposed to explain Arctic amplification. These mechanisms include the surface albedo feedback and poleward sensible and latent heat transport processes. During the winter season when Arctic amplification is most pronounced, the first mechanism relies on an enhancement in upward surface heat flux, while the second mechanism does not. In these mechanisms, it has been proposed that downward infrared radiation (IR) plays a role to a varying degree. Here, we show that the current generation of CMIP5 climate models all reproduce Arctic warming and there are high pattern correlations—typically greater than 0.9—between the surface air temperature (SAT) trend and the downward IR trend. However, we find that there are two groups of CMIP5 models: one with small pattern correlations between the Arctic SAT trend and the surface vertical heat flux trend (Group 1), and the other with large correlations (Group 2) between the same two variables. The Group 1 models exhibit higher pattern correlations between Arctic SAT and 500 hPa geopotential height trends, than do the Group 2 models. These findings suggest that Arctic warming in Group 1 models is more closely related to changes in the large-scale atmospheric circulation, whereas in Group 2, the albedo feedback effect plays a more important role. Interestingly, while Group 1 models have a warm or weak bias in their Arctic SAT, Group 2 models show large cold biases. This stark difference in model bias leads us to hypothesize that for a given model, the dominant Arctic warming mechanism and trend may be dependent on the bias of the model mean state.

  17. Seasonal Clear-Sky Flux and Cloud Radiative Effect Anomalies in the Arctic Atmospheric Column Associated with the Arctic Oscillation and Arctic Dipole

    Science.gov (United States)

    Hegyi, Bradley M.; Taylor, Patrick C.

    2017-01-01

    The impact of the Arctic Oscillation (AO) and Arctic Dipole (AD) on the radiative flux into the Arctic mean atmospheric column is quantified. 3-month-averaged AO and AD indices are regressed with corresponding surface and top-of-atmosphere (TOA) fluxes from the CERES-SFC and CERES-TOA EBAF datasets over the period 2000-2014. An increase in clear-sky fluxes into the Arctic mean atmospheric column during fall is the largest net flux anomaly associated with AO, primarily driven by a positive net longwave flux anomaly (i.e. increase of net flux into the atmospheric column) at the surface. A decrease in the Arctic mean atmospheric column cloud radiative effect during winter and spring is the largest flux anomaly associated with AD, primarily driven by a change in the longwave cloud radiative effect at the surface. These prominent responses to AO and AD are widely distributed across the ice-covered Arctic, suggesting that the physical process or processes that bring about the flux change associated with AO and AD are distributed throughout the Arctic.

  18. Restoring sediment to compensate for human-induced erosion of an estuarine shore

    Science.gov (United States)

    Nordstrom, Karl F.; Jackson, Nancy L.; Farrell, Eugene J.; Rafferty, Patricia; Tengwall, Charles

    2016-06-01

    Shoreline erosion is often exacerbated by reduction of sediment inputs because of interference with sediment transport by human structures. We evaluate use of sediment dredged from a navigation channel to establish a feeder beach adjacent to a bulkhead as a solution for addressing erosion of landforms and habitats on sandy estuarine shores. The objectives are to determine how beach volume, position and shape within and downdrift of the fill area change and whether the volumes supplied by dredging match sediment losses caused by human actions. The fill was placed along a 75 m length of shoreline adjacent to a marina in Great South Bay at Fire Island, New York, USA. Changes in beach shape and volume were determined from topographic surveys conducted before and after fill and at half year intervals for 18 months. The quantity of fill was 1747 m3. Maximum shoreline advance due to fill emplacement was 20.7 m. The maximum volume placed at any transect was 28.6 m3 m- 1 of shoreline length. Erosion of the fill occurred rapidly, with landward migration of a conspicuous scarp. The edge of the upland 18 months after the fill was placed was up to 4.6 m farther landward than prior to the fill. Movement of sediment alongshore downdrift of the fill occurred as wave-like pulses, extending the active foreshore bayward, causing accretion of the inner low tide terrace, burying saltmarsh peat outcrops on the foreshore and creating a higher and wider overwash platform over portions of the saltmarshes. Landforms downdrift of the fill area underwent successive stages including erosion (pre-nourishment), accretion, stability (with throughput of sediment) and then erosion. Beach nourishment compensates for human-induced sediment losses. The volume of sediment added from maintenance dredging can slow the rate of erosion but may not prevent long-term shoreline retreat. Restoration and maintenance of coastal landforms and habitats to specific target states at a given location is difficult

  19. Hepatic Differentiation of Human Induced Pluripotent Stem Cells in a Perfused Three-Dimensional Multicompartment Bioreactor

    Directory of Open Access Journals (Sweden)

    Nora Freyer

    2016-08-01

    Full Text Available The hepatic differentiation of human induced pluripotent stem cells (hiPSC holds great potential for application in regenerative medicine, pharmacological drug screening, and toxicity testing. However, full maturation of hiPSC into functional hepatocytes has not yet been achieved. In this study, we investigated the potential of a dynamic three-dimensional (3D hollow fiber membrane bioreactor technology to improve the hepatic differentiation of hiPSC in comparison to static two-dimensional (2D cultures. A total of 100 × 106 hiPSC were seeded into each 3D bioreactor (n = 3. Differentiation into definitive endoderm (DE was induced by adding activin A, Wnt3a, and sodium butyrate to the culture medium. For further maturation, hepatocyte growth factor and oncostatin M were added. The same differentiation protocol was applied to hiPSC maintained in 2D cultures. Secretion of alpha-fetoprotein (AFP, a marker for DE, was significantly (p < 0.05 higher in 2D cultures, while secretion of albumin, a typical characteristic for mature hepatocytes, was higher after hepatic differentiation of hiPSC in 3D bioreactors. Functional analysis of multiple cytochrome P450 (CYP isoenzymes showed activity of CYP1A2, CYP2B6, and CYP3A4 in both groups, although at a lower level compared to primary human hepatocytes (PHH. CYP2B6 activities were significantly (p < 0.05 higher in 3D bioreactors compared with 2D cultures, which is in line with results from gene expression. Immunofluorescence staining showed that the majority of cells was positive for albumin, cytokeratin 18 (CK18, and hepatocyte nuclear factor 4-alpha (HNF4A at the end of the differentiation process. In addition, cytokeratin 19 (CK19 staining revealed the formation of bile duct-like structures in 3D bioreactors similar to native liver tissue. The results indicate a better maturation of hiPSC in the 3D bioreactor system compared to 2D cultures and emphasize the potential of dynamic 3D culture

  20. Hepatic Differentiation of Human Induced Pluripotent Stem Cells in a Perfused Three-Dimensional Multicompartment Bioreactor

    Science.gov (United States)

    Freyer, Nora; Knöspel, Fanny; Strahl, Nadja; Amini, Leila; Schrade, Petra; Bachmann, Sebastian; Damm, Georg; Seehofer, Daniel; Jacobs, Frank; Monshouwer, Mario; Zeilinger, Katrin

    2016-01-01

    Abstract The hepatic differentiation of human induced pluripotent stem cells (hiPSC) holds great potential for application in regenerative medicine, pharmacological drug screening, and toxicity testing. However, full maturation of hiPSC into functional hepatocytes has not yet been achieved. In this study, we investigated the potential of a dynamic three-dimensional (3D) hollow fiber membrane bioreactor technology to improve the hepatic differentiation of hiPSC in comparison to static two-dimensional (2D) cultures. A total of 100 × 106 hiPSC were seeded into each 3D bioreactor (n = 3). Differentiation into definitive endoderm (DE) was induced by adding activin A, Wnt3a, and sodium butyrate to the culture medium. For further maturation, hepatocyte growth factor and oncostatin M were added. The same differentiation protocol was applied to hiPSC maintained in 2D cultures. Secretion of alpha-fetoprotein (AFP), a marker for DE, was significantly (p < 0.05) higher in 2D cultures, while secretion of albumin, a typical characteristic for mature hepatocytes, was higher after hepatic differentiation of hiPSC in 3D bioreactors. Functional analysis of multiple cytochrome P450 (CYP) isoenzymes showed activity of CYP1A2, CYP2B6, and CYP3A4 in both groups, although at a lower level compared to primary human hepatocytes (PHH). CYP2B6 activities were significantly (p < 0.05) higher in 3D bioreactors compared with 2D cultures, which is in line with results from gene expression. Immunofluorescence staining showed that the majority of cells was positive for albumin, cytokeratin 18 (CK18), and hepatocyte nuclear factor 4-alpha (HNF4A) at the end of the differentiation process. In addition, cytokeratin 19 (CK19) staining revealed the formation of bile duct-like structures in 3D bioreactors similar to native liver tissue. The results indicate a better maturation of hiPSC in the 3D bioreactor system compared to 2D cultures and emphasize the potential of dynamic 3D culture

  1. Application of Method of Variation to Analyze and Predict Human Induced Modifications of Water Resource Systems

    Science.gov (United States)

    Dessu, S. B.; Melesse, A. M.; Mahadev, B.; McClain, M.

    2010-12-01

    marginal benefit is maximized. Therefore, the variation model can help to predict the possible human induced modification of natural water system in order to gain the maximum productivity and benefit.

  2. Multidecadal trends in aerosol radiative forcing over the Arctic: Contribution of changes in anthropogenic aerosol to Arctic warming since 1980

    Science.gov (United States)

    Breider, Thomas J.; Mickley, Loretta J.; Jacob, Daniel J.; Ge, Cui; Wang, Jun; Payer Sulprizio, Melissa; Croft, Betty; Ridley, David A.; McConnell, Joseph R.; Sharma, Sangeeta; Husain, Liaquat; Dutkiewicz, Vincent A.; Eleftheriadis, Konstantinos; Skov, Henrik; Hopke, Phillip K.

    2017-03-01

    Arctic observations show large decreases in the concentrations of sulfate and black carbon (BC) aerosols since the early 1980s. These near-term climate-forcing pollutants perturb the radiative balance of the atmosphere and may have played an important role in recent Arctic warming. We use the GEOS-Chem global chemical transport model to construct a 3-D representation of Arctic aerosols that is generally consistent with observations and their trends from 1980 to 2010. Observations at Arctic surface sites show significant decreases in sulfate and BC mass concentrations of 2-3% per year. We find that anthropogenic aerosols yield a negative forcing over the Arctic, with an average 2005-2010 Arctic shortwave radiative forcing (RF) of -0.19 ± 0.05 W m-2 at the top of atmosphere (TOA). Anthropogenic sulfate in our study yields more strongly negative forcings over the Arctic troposphere in spring (-1.17 ± 0.10 W m-2) than previously reported. From 1980 to 2010, TOA negative RF by Arctic aerosol declined, from -0.67 ± 0.06 W m-2 to -0.19 ± 0.05 W m-2, yielding a net TOA RF of +0.48 ± 0.06 W m-2. The net positive RF is due almost entirely to decreases in anthropogenic sulfate loading over the Arctic. We estimate that 1980-2010 trends in aerosol-radiation interactions over the Arctic and Northern Hemisphere midlatitudes have contributed a net warming at the Arctic surface of +0.27 ± 0.04 K, roughly one quarter of the observed warming. Our study does not consider BC emissions from gas flaring nor the regional climate response to aerosol-cloud interactions or BC deposition on snow.

  3. Expansion of vegetated coastal ecosystems in the future Arctic

    Directory of Open Access Journals (Sweden)

    Dorte eKrause-Jensen

    2014-12-01

    Full Text Available Warming occurs particularly fast in the Arctic and exerts profound effects on arctic ecosystems. Sea ice-associated ecosystems are projected to decline but reduced arctic sea ice cover also increases the solar radiation reaching the coastal seafloors with the potential for expansion of vegetated habitats, i.e. kelp forests and seagrass meadows. These habitats support key ecosystem functions, some of which may mitigate effects of climate change. Therefore, the likely expansion of vegetated coastal habitats in the Arctic will generate new productive ecosystems, offer habitat for a number of invertebrate and vertebrate species, including provision of refugia for calcifiers from possible threats from ocean acidification, contribute to enhance CO2 sequestration and protect the shoreline from erosion. The development of models allowing quantitative forecasts of the future of vegetated arctic ecosystems requires that key hypotheses underlying such forecasts be tested. Here we propose a set of three key testable hypotheses along with a research agenda for testing them using a broad diversity of approaches, including analyses of paleo-records, space for-time substitutions and experimental studies. The research agenda proposed would provide a solid underpinning to guide forecasts on the spread of marine macrophytes onto the Arctic with climate change and contribute to balance our understanding of climate change impacts on the arctic ecosystem through a focus on the role of engineering species. Anticipating these changes in ecosystem structure and function is key to develop managerial strategies to maximize these ecosystem services in a future warmer Arctic.

  4. Changes in the Arctic: Background and Issues for Congress

    Science.gov (United States)

    2014-03-28

    International Trade in Endangered Species of Wild Fauna and Flora , the Convention on Long Range Transboundary Air Pollution and its protocols, and the... International Relations, Foreign Affairs, Defense, and Trade Division. 32 The United States is party to the four conventions adopted in 1958...management of Arctic fish stocks. Changes in the Arctic could affect threatened and endangered species . Under the Endangered

  5. Siberian Arctic black carbon sources constrained by model and observation

    Science.gov (United States)

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-02-01

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ngṡm-3 to 302 ngṡm-3) and dual-isotope-constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  6. High-Arctic butterflies become smaller with rising temperatures

    DEFF Research Database (Denmark)

    Bowden, Joseph James; Eskildsen, Anne; Hansen, Rikke Reisner

    2015-01-01

    size but long growing seasons could also increase body size as was recently shown in an Arctic spider species. Here, we present the longest known time series on body size variation in two High-Arctic butterfly species: Boloria chariclea and Colias hecla. We measured wing length of nearly 4500...

  7. Atopic sensitization among children in an arctic environment

    DEFF Research Database (Denmark)

    Krause, T G; Koch, A; Poulsen, Lars K.;

    2002-01-01

    Asthma has been reported to be rare among Inuits, but so far total and specific IgE levels have never been determined in arctic populations.......Asthma has been reported to be rare among Inuits, but so far total and specific IgE levels have never been determined in arctic populations....

  8. Arctic methane sources: Isotopic evidence for atmospheric inputs

    NARCIS (Netherlands)

    Fisher, R.E.; Sriskantharajah, S.; Lowry, D.; Lanoisellé, M.; Fowler, C.M.R.; James, R.H.; Hermansen, O.; Lund Myhre, C.; Stohl, A.; Greinert, J.; Nisbet-Jones, P.B.R.; Mienert, J.; Nisbet, E.G.

    2011-01-01

    By comparison of the methane mixing ratio and the carbon isotope ratio (delta C-13(CH4)) in Arctic air with regional background, the incremental input of CH4 in an air parcel and the source delta C-13(CH4) signature can be determined. Using this technique the bulk Arctic CH4 source signature of air

  9. Global Warming Threatens National Interests in the Arctic

    Science.gov (United States)

    2009-03-26

    Global warming has impacted the Arctic Ocean by significantly reducing the extent of the summer ice cover allowing greater access to the region...increased operations in the Arctic region, and DoD must continue to research and develop new and alternate energy sources for its forces. Global warming is

  10. Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

    NARCIS (Netherlands)

    Kim, J.-H.; Peterse, F.; Willmott, V.; Klitgaard Kristensen, D.; Baas, M.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Soils, fine-grained ice-rafted detritus (IRD), coals, and marine surface sediments in the Arctic realm (Svalbard) were collected in 2007 and 2008 to characterize organic matter (OM) sources in Arctic marine sediments. Bulk geochemical (C : N ratio and stable carbon isotopic composition) parameters s

  11. Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

    NARCIS (Netherlands)

    Kim, J.-H.; Peterse, F.; Willmott, V.; Klitgaard Kristensen, D.; Baas, M.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Soils, fine-grained ice-rafted detritus (IRD), coals, and marine surface sediments in the Arctic realm (Svalbard)were collected in 2007 and 2008 to characterize organic matter (OM) sources in Arctic marine sediments. Bulkgeochemical (C : N ratio and stable carbon isotopic composition) parameters sug

  12. Future-Proofing Japan’s Interests in the Arctic

    DEFF Research Database (Denmark)

    Tonami, Aki

    2014-01-01

    In May 2013 the Arctic states convened in Kiruna, Sweden, in part to decide on whether six new states should be admitted as observers to the Arctic Council. Japan’s application was accepted along with those of China,India, Italy, Singapore, and South Korea. At a glance, one might ask what credent...

  13. Peeking into the future : fungi in the greening Arctic

    NARCIS (Netherlands)

    Neves Morgado, Luis Miguel das

    2016-01-01

    In the last decades, average land surface temperatures in the Arctic have increased at rates up to six times higher than the global average increase. Similarly, precipitation in the Arctic also increased, especially during the cold season when most precipitation falls as snow. In this thesis, the lo

  14. Deep Arctic Ocean warming during the last glacial cycle

    Science.gov (United States)

    Cronin, T. M.; Dwyer, G.S.; Farmer, J.; Bauch, H.A.; Spielhagen, R.F.; Jakobsson, M.; Nilsson, J.; Briggs, W.M.; Stepanova, A.

    2012-01-01

    In the Arctic Ocean, the cold and relatively fresh water beneath the sea ice is separated from the underlying warmer and saltier Atlantic Layer by a halocline. Ongoing sea ice loss and warming in the Arctic Ocean have demonstrated the instability of the halocline, with implications for further sea ice loss. The stability of the halocline through past climate variations is unclear. Here we estimate intermediate water temperatures over the past 50,000 years from the Mg/Ca and Sr/Ca values of ostracods from 31 Arctic sediment cores. From about 50 to 11 kyr ago, the central Arctic Basin from 1,000 to 2,500 m was occupied by a water mass we call Glacial Arctic Intermediate Water. This water mass was 1–2 °C warmer than modern Arctic Intermediate Water, with temperatures peaking during or just before millennial-scale Heinrich cold events and the Younger Dryas cold interval. We use numerical modelling to show that the intermediate depth warming could result from the expected decrease in the flux of fresh water to the Arctic Ocean during glacial conditions, which would cause the halocline to deepen and push the warm Atlantic Layer into intermediate depths. Although not modelled, the reduced formation of cold, deep waters due to the exposure of the Arctic continental shelf could also contribute to the intermediate depth warming.

  15. Arctic Climate Change: A Tale of Two Cod Species

    Science.gov (United States)

    Arctic cod play an important role in the Arctic trophic hierarchy as the consumer of primary productivity and a food source for many marine fish and mammals. Shifts in their distribution and abundance could have cascading affects in the marine environment. This paper investigates...

  16. The Alaska Arctic Vegetation Archive (AVA-AK)

    NARCIS (Netherlands)

    Walker, Donald A.; Breen, Amy L.; Druckenmiller, Lisa A.; Wirth, Lisa W.; Fisher, Will; Raynolds, Martha K.; Šibík, Jozef; Walker, Marilyn D.; Hennekens, Stephan; Boggs, Keith; Boucher, Tina; Buchhorn, Marcel; Bültmann, Helga; Cooper, David J.; Daniëls, Fred J.A.; Davidson, Scott J.; Ebersole, James J.; Elmendorf, Sara C.; Epstein, Howard E.; Gould, William A.; Hollister, Robert D.; Iversen, Colleen M.; Jorgenson, M.T.; Kade, Anja; Lee, Michael T.; MacKenzie, William H.; Peet, Robert K.; Peirce, Jana L.; Schickhoff, Udo; Sloan, Victoria L.; Talbot, Stephen S.; Tweedie, Craig E.; Villarreal, Sandra; Webber, Patrick J.; Zona, Donatella

    2016-01-01

    The Alaska Arctic Vegetation Archive (AVA-AK, GIVD-ID: NA-US-014) is a free, publically available database archive of vegetation-plot data from the Arctic tundra region of northern Alaska. The archive currently contains 24 datasets with 3,026 non-overlapping plots. Of these, 74% have geolocation dat

  17. Processes and impacts of Arctic amplification: A research synthesis

    Science.gov (United States)

    Serreze, Mark C.; Barry, Roger G.

    2011-05-01

    The past decade has seen substantial advances in understanding Arctic amplification — that trends and variability in surface air temperature tend to be larger in the Arctic region than for the Northern Hemisphere or globe as a whole. We provide a synthesis of research on Arctic amplification, starting with a historical context and then addressing recent insights into processes and key impacts, based on analysis of the instrumental record, modeling studies, and paleoclimate reconstructions. Arctic amplification is now recognized as an inherent characteristic of the global climate system, with multiple intertwined causes operating on a spectrum of spatial and temporal scales. These include, but are not limited to, changes in sea ice extent that impact heat fluxes between the ocean and the atmosphere, atmospheric and oceanic heat transports, cloud cover and water vapor that alter the longwave radiation flux to the surface, soot on snow and heightened black carbon aerosol concentrations. Strong warming over the Arctic Ocean during the past decade in autumn and winter, clearly associated with reduced sea ice extent, is but the most recent manifestation of the phenomenon. Indeed, periods of Arctic amplification are evident from analysis of both warm and cool periods over at least the past three million years. Arctic amplification being observed today is expected to become stronger in coming decades, invoking changes in atmospheric circulation, vegetation and the carbon cycle, with impacts both within and beyond the Arctic.

  18. The progress in the study of Arctic pack ice ecology

    Institute of Scientific and Technical Information of China (English)

    何剑锋; 王桂忠; 蔡明红; 李少菁

    2004-01-01

    The sea ice community plays an important role in the Arctic marine ecosystem. Because of the predicted environmental changes in the Arctic environment and specifically related to sea ice, the Arctic pack ice biota has received more attention in recent years using modern ice-breaking research vessels. Studies show that the Arctic pack ice contains a diverse biota and besides ice algae, the bacterial and protozoan biomasses can be high. Surprisingly high primary production values were observed in the pack ice of the central Arctic Ocean. Occasionally biomass maximum were discovered in the interior of the ice floes, a habitat that had been ignored in most Arctic studies. Many scientific questions, which deserve special attention, remained unsolved due to logistic limitations and the sea ice characteristics. Little is know about the pack ice community in the central Arctic Ocean. Almost no data exists from the pack ice zone for the winter season. Concerning the abundance of bacteria and protozoa, more studies are needed to understand the microbial network within the ice and its role in material and energy flows. The response of the sea ice biota to global change will impact the entire Arctic marine ecosystem and a long-term monitoring program is needed. The techniques, that are applied to study the sea ice biota and the sea ice ecology, should be improved.

  19. Fresh Water Content Variability in the Arctic Ocean

    Science.gov (United States)

    Hakkinen, Sirpa; Proshutinsky, Andrey

    2003-01-01

    Arctic Ocean model simulations have revealed that the Arctic Ocean has a basin wide oscillation with cyclonic and anticyclonic circulation anomalies (Arctic Ocean Oscillation; AOO) which has a prominent decadal variability. This study explores how the simulated AOO affects the Arctic Ocean stratification and its relationship to the sea ice cover variations. The simulation uses the Princeton Ocean Model coupled to sea ice. The surface forcing is based on NCEP-NCAR Reanalysis and its climatology, of which the latter is used to force the model spin-up phase. Our focus is to investigate the competition between ocean dynamics and ice formation/melt on the Arctic basin-wide fresh water balance. We find that changes in the Atlantic water inflow can explain almost all of the simulated fresh water anomalies in the main Arctic basin. The Atlantic water inflow anomalies are an essential part of AOO, which is the wind driven barotropic response to the Arctic Oscillation (AO). The baroclinic response to AO, such as Ekman pumping in the Beaufort Gyre, and ice meldfreeze anomalies in response to AO are less significant considering the whole Arctic fresh water balance.

  20. What Should Children Know about the Arctic Ocean?

    Science.gov (United States)

    Stockard, James W., Jr.

    1989-01-01

    Lists essential information about the Arctic Ocean which should be taught in elementary social studies courses, and which teacher training programs should cover. Discusses popular misconceptions regarding the Arctic Ocean and factors, such as the coloration on maps and globes, which lead to these misconceptions. (LS)

  1. Ecological dynamics across the Arctic associated with recent climate change

    Science.gov (United States)

    Eric Post; Mads C. Forchhammer; M. Syndonia Bret-Harte; Terry V. Callaghan; Torben R. Christensen; Bo Elberling; Anthony D. Fox; Olivier Gilg; David S. Hik; Toke T. Høye; Rolf A. Ims; Erik Jeppesen; David R. Klein; Jesper Madsen; A. David McGuire; Søren Rysgaard; Daniel E. Schindler; Ian Stirling; Mikkel P. Tamstorf; Nicholas J.C. Tyler; Rene van der Wal; Jeffrey Welker; Philip A. Wookey; Niels Martin Schmidt; Peter. Aastrup

    2009-01-01

    At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These...

  2. Adapting Governance and Regulation of the Marine Arctic

    NARCIS (Netherlands)

    Molenaar, Erik

    2014-01-01

    The Arctic is currently undergoing change at a pace many would not have considered possible just a decade or so ago. It is therefore reasonable to argue that while the international law and policy regime for the governance and regulation of the marine Arctic may have been adequate for an ice-dominat

  3. Arctic Cities and Climate Change: A Geographic Impact Assessment

    Science.gov (United States)

    Shiklomanov, N. I.; Streletskiy, D. A.

    2014-12-01

    Arctic climate change is a concern for the engineering community, land-use planners and policy makers as it may have significant impacts on socio-economic development and human activities in the northern regions. A warmer climate has potential for a series of positive economic effects, such as development of maritime transportation, enhanced agricultural production and decrease in energy consumption. However, these potential benefits may be outwaited by negative impacts related to transportation accessibility and stability of existing infrastructure, especially in permafrost regions. Compared with the Arctic zones of other countries, the Russian Arctic is characterized by higher population, greater industrial development and urbanization. Arctic urban areas and associated industrial sites are the location of some of intense interaction between man and nature. However, while there is considerable research on various aspects of Arctic climate change impacts on human society, few address effects on Arctic cities and their related industries. This presentation overviews potential climate-change impacts on Russian urban environments in the Arctic and discusses methodology for addressing complex interactions between climatic, permafrost and socio-economic systems at the range of geographical scales. We also provide a geographic assessment of selected positive and negative climate change impacts affecting several diverse Russian Arctic cities.

  4. The Arctic Climate Modeling Program: Professional Development for Rural Teachers

    Science.gov (United States)

    Bertram, Kathryn Berry

    2010-01-01

    The Arctic Climate Modeling Program (ACMP) offered yearlong science, technology, engineering, and math (STEM) professional development to teachers in rural Alaska. Teacher training focused on introducing youth to workforce technologies used in Arctic research. Due to challenges in making professional development accessible to rural teachers, ACMP…

  5. The genetic prehistory of the New World Arctic

    DEFF Research Database (Denmark)

    Raghavan, Maanasa; DeGiorgio, Michael; Albrechtsen, Anders

    2014-01-01

    The New World Arctic, the last region of the Americas to be populated by humans, has a relatively well-researched archaeology, but an understanding of its genetic history is lacking. We present genome-wide sequence data from ancient and present-day humans from Greenland, Arctic Canada, Alaska...

  6. Towards Arctic Resource Governance of Marine Invasive Species

    DEFF Research Database (Denmark)

    Kourantidou, Melina; Kaiser, Brooks; Fernandez, Linda

    2015-01-01

    research into invasive species threats in the Arctic, including the ways in which known marine invasions are related to different stakeholder groups and existing disparate national and international experiences with invasive species. Stakeholdergroups include dominant industries (fishing, shipping, tourism...... gaps derived from systematic research limitations and opportunities in the Arctic environment....

  7. The Alaska Arctic Vegetation Archive (AVA-AK)

    NARCIS (Netherlands)

    Walker, Donald A.; Breen, Amy L.; Druckenmiller, Lisa A.; Wirth, Lisa W.; Fisher, Will; Raynolds, Martha K.; Šibík, Jozef; Walker, Marilyn D.; Hennekens, Stephan; Boggs, Keith; Boucher, Tina; Buchhorn, Marcel; Bültmann, Helga; Cooper, David J.; Daniëls, Fred J.A.; Davidson, Scott J.; Ebersole, James J.; Elmendorf, Sara C.; Epstein, Howard E.; Gould, William A.; Hollister, Robert D.; Iversen, Colleen M.; Jorgenson, M.T.; Kade, Anja; Lee, Michael T.; MacKenzie, William H.; Peet, Robert K.; Peirce, Jana L.; Schickhoff, Udo; Sloan, Victoria L.; Talbot, Stephen S.; Tweedie, Craig E.; Villarreal, Sandra; Webber, Patrick J.; Zona, Donatella

    2016-01-01

    The Alaska Arctic Vegetation Archive (AVA-AK, GIVD-ID: NA-US-014) is a free, publically available database archive of vegetation-plot data from the Arctic tundra region of northern Alaska. The archive currently contains 24 datasets with 3,026 non-overlapping plots. Of these, 74% have geolocation

  8. Trouble in NIFLHEIM Elements of a NATO Arctic Strategy

    Science.gov (United States)

    2015-06-01

    diamonds, palladium, tin, copper , platinum and others are already mined in the Arctic; moreover, further deposits are projected. The Norilsk Mining...cobalt, 60% of its copper , and 96% of its platinum.41 In addition to conventional mineral deposits, the Arctic is rich in rare earth elements...emphasizes four pillars : sovereignty; environmental protection; social and economic development, herein responsible extraction of hydrocarbons and

  9. Beyond Thin Ice: Co-Communicating the Many Arctics

    Science.gov (United States)

    Druckenmiller, M. L.; Francis, J. A.; Huntington, H.

    2015-12-01

    Science communication, typically defined as informing non-expert communities of societally relevant science, is persuaded by the magnitude and pace of scientific discoveries, as well as the urgency of societal issues wherein science may inform decisions. Perhaps nowhere is the connection between these facets stronger than in the marine and coastal Arctic where environmental change is driving advancements in our understanding of natural and socio-ecological systems while paving the way for a new assortment of arctic stakeholders, who generally lack adequate operational knowledge. As such, the Arctic provides opportunity to advance the role of science communication into a collaborative process of engagement and co-communication. To date, the communication of arctic change falls within four primary genres, each with particular audiences in mind. The New Arctic communicates an arctic of new stakeholders scampering to take advantage of unprecedented access. The Global Arctic conveys the Arctic's importance to the rest of the world, primarily as a regulator of lower-latitude climate and weather. The Intra-connected Arctic emphasizes the increasing awareness of the interplay between system components, such as between sea ice loss and marine food webs. The Transforming Arctic communicates the region's trajectory relative to the historical Arctic, acknowledging the impacts on indigenous peoples. The broad societal consensus on climate change in the Arctic as compared to other regions in the world underscores the opportunity for co-communication. Seizing this opportunity requires the science community's engagement with stakeholders and indigenous peoples to construct environmental change narratives that are meaningful to climate responses relative to non-ecological priorities (e.g., infrastructure, food availability, employment, or language). Co-communication fosters opportunities for new methods of and audiences for communication, the co-production of new interdisciplinary

  10. Dominant patterns of winter Arctic surface wind variability

    Institute of Scientific and Technical Information of China (English)

    WU Bingyi; John Walsh; LIU Jiping; ZHANG Xiangdong

    2014-01-01

    Dominant statistical patterns of winter Arctic surface wind (WASW) variability and their impacts on Arctic sea ice motion are investigated using the complex vector empirical orthogonal function (CVEOF) method. The results indicate that the leading CVEOF of Arctic surface wind variability, which accounts for 33% of the covariance, is characterized by two different and alternating spatial patterns (WASWP1 and WASWP2). Both WASWP1 and WASWP2 show strong interannual and decadal variations, superposed on their declining trends over past decades. Atmospheric circulation anomalies associated with WASWP1 and WASWP2 exhibit, respectively, equivalent barotropic and some baroclinic characteristics, differing from the Arctic dipole anomaly and the seesaw structure anomaly between the Barents Sea and the Beaufort Sea. On decadal time scales, the decline trend of WASWP2 can be attributed to persistent warming of sea surface temperature in the Greenland—Barents—Kara seas from autumn to winter, relfecting the effect of the Arctic warming. The second CVEOF, which accounts for 18% of the covariance, also contains two different spatial patterns (WASWP3 and WASWP4). Their time evolutions are signiifcantly correlated with the North Atlantic Oscillation (NAO) index and the central Arctic Pattern, respectively, measured by the leading EOF of winter sea level pressure (SLP) north of 70°N. Thus, winter anomalous surface wind pattern associated with the NAO is not the most important surface wind pattern. WASWP3 and WASWP4 primarily relfect natural variability of winter surface wind and neither exhibits an apparent trend that differs from WASWP1 or WASWP2. These dominant surface wind patterns strongly inlfuence Arctic sea ice motion and sea ice exchange between the western and eastern Arctic. Furthermore, the Fram Strait sea ice volume lfux is only signiifcantly correlated with WASWP3. The results demonstrate that surface and geostrophic winds are not interchangeable in terms of

  11. Little Fish, Big Pond: Icelandic Interests and Influence in Arctic Governance

    Directory of Open Access Journals (Sweden)

    Rachael L. Johnstone

    2016-05-01

    Full Text Available The paper presents the Arctic Council and Iceland’s role within it before turning to issues that are governed outside of the Arctic Council system, in particular, Arctic fisheries and maritime boundaries. The paper explains Iceland’s approach to Arctic cooperation in light of its published policy documents and explore the tools available to Iceland to defend its interests.

  12. Arctic autumn sea ice decline and Asian winter temperature anomaly

    Institute of Scientific and Technical Information of China (English)

    LIU Na; LIN Lina; WANG Yingjie; KONG Bin; ZHANG Zhanhai; CHEN Hongxia

    2016-01-01

    Associations between the autumn Arctic sea ice concentration (SIC) and Asian winter temperature are discussed using the singular value decomposition analysis. Results show that in recent 33 years reduced autumn Arctic sea ice is accompanied by Asian winter temperature decrease except in the Tibetan plateau and the Arctic Ocean and the North Pacific Ocean coast. The autumn SIC reduction excites two geopotential height centers in Eurasia and the north Arctic Ocean, which are persistent from autumn to winter. The negative center is in Barents Sea/Kara Sea. The positive center is located in Mongolia. The anomalous winds are associated with geopotential height centers, providing favorable clod air for the Asian winter temperature decreasing in recent 33 years. This relationship indicates a potential long-term outlook for the Asian winter temperature decrease as the decline of the autumn sea ice in the Arctic Ocean is expected to continue as climate warms.

  13. Carbon, Climate and Cameras: Showcasing Arctic research through multimedia storytelling

    Science.gov (United States)

    Tachihara, B. L.; Linder, C. A.; Holmes, R. M.

    2011-12-01

    In July 2011, Tachihara spent three weeks in the Siberian Arctic documenting The Polaris Project, an NSF-funded effort that brings together an international group of undergraduate students and research scientists to study Arctic systems. Using a combination of photography, video and interviews gathered during the field course, we produced a six-minute film focusing on the researchers' quest to track carbon as it moves from terrestrial upland areas into lakes, streams, rivers and eventually into the Arctic Ocean. The overall goal was to communicate the significance of Arctic science in the face of changing climate. Using a selection of clips from the 2011 video, we will discuss the advantages and challenges specific to using multimedia presentations to represent Arctic research, as well as science in general. The full video can be viewed on the Polaris website: http://www.thepolarisproject.org.

  14. The last deglaciation event in the eastern central arctic ocean.

    Science.gov (United States)

    Stein, R; Nam, S I; Schubert, C; Vogt, C; Futterer, D; Heinemeier, J

    1994-04-29

    Oxygen isotope records of cores from the central Arctic Ocean yield evidence for a major influx of meltwater at the beginning of the last deglaciation 15.7 thousand years ago (16,650 calendar years B.C.). The almost parallel trends of the isotope records from the Arctic Ocean, the Fram Strait, and the east Greenland continental margin suggest contemporaneous variations of the Eurasian Arctic and Greenland (Laurentide) ice sheets or increased export of low-saline waters from the Arctic within the East Greenland Current during the last deglaciation. On the basis of isotope and carbon data, the modern surface- and deep-water characteristics and seasonally open-ice conditions with increased surface-water productivity were established in the central Arctic at the end of Termination lb about 7.2 thousand years ago or 6,000 calendar years B.C.).

  15. The 1994 Arctic Ocean Section. The First Major Scientific Crossing of the Arctic Ocean,

    Science.gov (United States)

    1996-09-01

    chlorofluorocarbons (CFCs), helium, oxygen, CO2 system components, AMS 14C, tritium, 18O, nutrients, salinity, trace metals, radionuclides and organic contaminants...spatial and temporal extremes in the rate of biological sequestration of atmospheric CO2 , ranging from oligotrophic conditions in the central Arctic to...paleoceanographic or paleoatmospheric circulation patterns and contribute to better paleoclimate reconstructions. Surface sediments collected along

  16. Evaluation of Arctic Sea Ice Thickness Simulated by Arctic Ocean Model Intercomparison Project Models

    Science.gov (United States)

    Johnson, Mark; Proshuntinsky, Andrew; Aksenov, Yevgeny; Nguyen, An T.; Lindsay, Ron; Haas, Christian; Zhang, Jinlun; Diansky, Nikolay; Kwok, Ron; Maslowski, Wieslaw; Hakkinen, Sirpa; Ashik, Igor; De Cuevas, Beverly

    2012-01-01

    Six Arctic Ocean Model Intercomparison Project model simulations are compared with estimates of sea ice thickness derived from pan-Arctic satellite freeboard measurements (2004-2008); airborne electromagnetic measurements (2001-2009); ice draft data from moored instruments in Fram Strait, the Greenland Sea, and the Beaufort Sea (1992-2008) and from submarines (1975-2000); and drill hole data from the Arctic basin, Laptev, and East Siberian marginal seas (1982-1986) and coastal stations (1998-2009). Despite an assessment of six models that differ in numerical methods, resolution, domain, forcing, and boundary conditions, the models generally overestimate the thickness of measured ice thinner than approximately 2 mand underestimate the thickness of ice measured thicker than about approximately 2m. In the regions of flat immobile landfast ice (shallow Siberian Seas with depths less than 25-30 m), the models generally overestimate both the total observed sea ice thickness and rates of September and October ice growth from observations by more than 4 times and more than one standard deviation, respectively. The models do not reproduce conditions of fast ice formation and growth. Instead, the modeled fast ice is replaced with pack ice which drifts, generating ridges of increasing ice thickness, in addition to thermodynamic ice growth. Considering all observational data sets, the better correlations and smaller differences from observations are from the Estimating the Circulation and Climate of the Ocean, Phase II and Pan-Arctic Ice Ocean Modeling and Assimilation System models.

  17. Strategic Assessment for Arctic Observing, and the New Arctic Observing Viewer

    Science.gov (United States)

    Kassin, A.; Cody, R. P.; Manley, W. F.; Gaylord, A. G.; Dover, M.; Score, R.; Lin, D. H.; Villarreal, S.; Quezada, A.; Tweedie, C. E.

    2013-12-01

    Although a great deal of progress has been made with various Arctic Observing efforts, it can be difficult to assess that progress. What data collection efforts are established or under way? Where? By whom? To help meet the strategic needs of SEARCH-AON, SAON, and related initiatives, a new resource has been released: the Arctic Observing Viewer (AOV; http://ArcticObservingViewer.org). This web mapping application covers the 'who', 'what', 'where', and 'when' of data collection sites - wherever marine or terrestrial data are collected. Hundreds of sites are displayed, providing an overview as well as details. Users can visualize, navigate, select, search, draw, print, and more. This application currently showcases a subset of observational activities and will become more comprehensive with time. The AOV is founded on principles of interoperability, with an emerging metadata standard and compatible web service formats, such that participating agencies and organizations can use the AOV tools and services for their own purposes. In this way, the AOV will complement other cyber-resources, and will help science planners, funding agencies, PI's, and others to: assess status, identify overlap, fill gaps, assure sampling design, refine network performance, clarify directions, access data, coordinate logistics, collaborate, and more to meet Arctic Observing goals.

  18. The Contribution to Arctic Climate Change from Countries in the Arctic Council

    Science.gov (United States)

    Schultz, T.; MacCracken, M. C.

    2013-12-01

    The conventional accounting frameworks for greenhouse gas (GHG) emissions used today, established under the Kyoto Protocol 25 years ago, exclude short lived climate pollutants (SLCPs), and do not include regional effects on the climate. However, advances in climate science now suggest that mitigation of SLCPs can reduce up to 50% of global warming by 2050. It has also become apparent that regions such as the Arctic have experienced a much greater degree of anthropogenic warming than the globe as a whole, and that efforts to slow this warming could benefit the larger effort to slow climate change around the globe. A draft standard for life cycle assessment (LCA), LEO-SCS-002, being developed under the American National Standards Institute process, has integrated the most recent climate science into a unified framework to account for emissions of all radiatively significant GHGs and SLCPs. This framework recognizes four distinct impacts to the oceans and climate caused by GHGs and SLCPs: Global Climate Change; Arctic Climate Change; Ocean Acidification; and Ocean Warming. The accounting for Arctic Climate Change, the subject of this poster, is based upon the Absolute Regional Temperature Potential, which considers the incremental change to the Arctic surface temperature resulting from an emission of a GHG or SLCP. Results are evaluated using units of mass of carbon dioxide equivalent (CO2e), which can be used by a broad array of stakeholders, including scientists, consumers, policy makers, and NGOs. This poster considers the contribution to Arctic Climate Change from emissions of GHGs and SLCPs from the eight member countries of the Arctic Council; the United States, Canada, Russia, Denmark, Finland, Iceland, Norway, and Sweden. Of this group of countries, the United States was the largest contributor to Arctic Climate Change in 2011, emitting 9600 MMT CO2e. This includes a gross warming of 11200 MMT CO2e (caused by GHGs, black and brown carbon, and warming effects

  19. Servicing the Arctic. Report 1: Design requirements and operational profile of an Arctic Offshore Support Vessel: Literature Survey

    NARCIS (Netherlands)

    Bos, R.W.; Huisman, T.J.; Obers, M.P.W.; Schaap, T.; Van der Zalm, M.

    2013-01-01

    Background The Dutch maritime industry has only limited knowledge about Arctic engineering, in spite of a growing market and interest by the oil and gas industry. This literature survey is the first in a series of three reports to develop a concept design of an Arctic Offshore Support Vessel

  20. Shifting El Niño inhibits summer Arctic warming and Arctic sea-ice melting over the Canada Basin

    Science.gov (United States)

    Hu, Chundi; Yang, Song; Wu, Qigang; Li, Zhenning; Chen, Junwen; Deng, Kaiqiang; Zhang, Tuantuan; Zhang, Chengyang

    2016-06-01

    Arctic climate changes include not only changes in trends and mean states but also strong interannual variations in various fields. Although it is known that tropical-extratropical teleconnection is sensitive to changes in flavours of El Niño, whether Arctic climate variability is linked to El Niño, in particular on interannual timescale, remains unclear. Here we demonstrate for the first time a long-range linkage between central Pacific (CP) El Niño and summer Arctic climate. Observations show that the CP warming related to CP El Niño events deepens the tropospheric Arctic polar vortex and strengthens the circumpolar westerly wind, thereby contributing to inhibiting summer Arctic warming and sea-ice melting. Atmospheric model experiments can generally capture the observed responses of Arctic circulation and robust surface cooling to CP El Niño forcing. We suggest that identification of the equator-Arctic teleconnection, via the `atmospheric bridge', can potentially contribute to improving the skill of predicting Arctic climate.