Investigation of Natural Circulation Instability and Transients in Passively Safe Small Modular Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishii, Mamoru

The NEUP funded project, NEUP-3496, aims to experimentally investigate two-phase natural circulation flow instability that could occur in Small Modular Reactors (SMRs), especially for natural circulation SMRs. The objective has been achieved by systematically performing tests to study the general natural circulation instability characteristics and the natural circulation behavior under start-up or design basis accident conditions. Experimental data sets highlighting the effect of void reactivity feedback as well as the effect of power ramp-up rate and system pressure have been used to develop a comprehensive stability map. The safety analysis code, RELAP5, has been used to evaluate experimental results andmore » models. Improvements to the constitutive relations for flashing have been made in order to develop a reliable analysis tool. This research has been focusing on two generic SMR designs, i.e. a small modular Simplified Boiling Water Reactor (SBWR) like design and a small integral Pressurized Water Reactor (PWR) like design. A BWR-type natural circulation test facility was firstly built based on the three-level scaling analysis of the Purdue Novel Modular Reactor (NMR) with an electric output of 50 MWe, namely NMR-50, which represents a BWR-type SMR with a significantly reduced reactor pressure vessel (RPV) height. The experimental facility was installed with various equipment to measure thermalhydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests were performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The control system and data acquisition system were programmed with LabVIEW to realize the realtime control and data storage. The thermal-hydraulic and nuclear coupled startup transients were performed to investigate the flow instabilities at low pressure and low power conditions for NMR-50. Two different power ramps were chosen to study the effect of startup power density on the flow instability. The experimental startup transient results showed the existence of three different flow instability mechanisms, i.e., flashing instability, condensation induced flow instability, and density wave oscillations. In addition, the void-reactivity feedback did not have significant effects on the flow instability during the startup transients for NMR-50. ii Several initial startup procedures with different power ramp rates were experimentally investigated to eliminate the flow instabilities observed from the startup transients. Particularly, the very slow startup transient and pressurized startup transient tests were performed and compared. It was found that the very slow startup transients by applying very small power density can eliminate the flashing oscillations in the single-phase natural circulation and stabilize the flow oscillations in the phase of net vapor generation. The initially pressurized startup procedure was tested to eliminate the flashing instability during the startup transients as well. The pressurized startup procedure included the initial pressurization, heat-up, and venting process. The startup transient tests showed that the pressurized startup procedure could eliminate the flow instability during the transition from single-phase flow to two-phase flow at low pressure conditions. The experimental results indicated that both startup procedures were applicable to the initial startup of NMR. However, the pressurized startup procedures might be preferred due to short operating hours required. In order to have a deeper understanding of natural circulation flow instability, the quasi-steady tests were performed using the test facility installed with preheater and subcooler. The effect of system pressure, core inlet subcooling, core power density, inlet flow resistance coefficient, and void reactivity feedback were investigated in the quasi-steady state tests. The experimental stability boundaries were determined between unstable and stable flow conditions in the dimensionless stability plane of inlet subcooling number and Zuber number. To predict the stability boundary theoretically, linear stability analysis in the frequency domain was performed at four sections of the natural circulation test loop. The flashing phenomena in the chimney section was considered as an axially uniform heat source. And the dimensionless characteristic equation of the pressure drop perturbation was obtained by considering the void fraction effect and outlet flow resistance in the core section. The theoretical flashing boundary showed some discrepancies with previous experimental data from the quasi-steady state tests. In the future, thermal non-equilibrium was recommended to improve the accuracy of flashing instability boundary. As another part of the funded research, flow instabilities of a PWR-type SMR under low pressure and low power conditions were investigated experimentally as well. The NuScale reactor design was selected as the prototype for the PWR-type SMR. In order to experimentally study the natural circulation behavior of NuScale iii reactor during accidental scenarios, detailed scaling analyses are necessary to ensure that the scaled phenomena could be obtained in a laboratory test facility. The three-level scaling method is used as well to obtain the scaling ratios derived from various non-dimensional numbers. The design of the ideally scaled facility (ISF) was initially accomplished based on these scaling ratios. Then the engineering scaled facility (ESF) was designed and constructed based on the ISF by considering engineering limitations including laboratory space, pipe size, and pipe connections etc. PWR-type SMR experiments were performed in this well-scaled test facility to investigate the potential thermal hydraulic flow instability during the blowdown events, which might occur during the loss of coolant accident (LOCA) and loss of heat sink accident (LOHS) of the prototype PWR-type SMR. Two kinds of experiments, normal blowdown event and cold blowdown event, were experimentally investigated and compared with code predictions. The normal blowdown event was experimentally simulated since an initial condition where the pressure was lower than the designed pressure of the experiment facility, while the code prediction of blowdown started from the normal operation condition. Important thermal hydraulic parameters including reactor pressure vessel (RPV) pressure, containment pressure, local void fraction and temperature, pressure drop and natural circulation flow rate were measured and analyzed during the blowdown event. The pressure and water level transients are similar to the experimental results published by NuScale [51], which proves the capability of current loop in simulating the thermal hydraulic transient of real PWR-type SMR. During the 20000s blowdown experiment, water level in the core was always above the active fuel assemble during the experiment and proved the safety of natural circulation cooling and water recycling design of PWR-type SMR. Besides, pressure, temperature, and water level transient can be accurately predicted by RELAP5 code. However, the oscillations of natural circulation flow rate, water level and pressure drops were observed during the blowdown transients. This kind of flow oscillations are related to the water level and the location upper plenum, which is a path for coolant flow from chimney to steam generator and down comer. In order to investigate the transients start from the opening of ADS valve in both experimental and numerical way, the cold blow-down experiment is conducted. For the cold blowdown event, different from setting both reactor iv pressure vessel (RPV) and containment at high temperature and pressure, only RPV was heated close to the highest designed pressure and then open the ADS valve, same process was predicted using RELAP5 code. By doing cold blowdown experiment, the entire transients from the opening of ADS can be investigated by code and benchmarked with experimental data. Similar flow instability observed in the cold blowdown experiment. The comparison between code prediction and experiment data showed that the RELAP5 code can successfully predict the pressure void fraction and temperature transient during the cold blowdown event with limited error, but numerical instability exists in predicting natural circulation flow rate. Besides, the code is lack of capability in predicting the water level related flow instability observed in experiments.« less

The impact of nudging coefficient for the initialization on the atmospheric flow field and the photochemical ozone concentration of Seoul, Korea

NASA Astrophysics Data System (ADS)

Choi, Hyun-Jung; Lee, Hwa Woon; Sung, Kyoung-Hee; Kim, Min-Jung; Kim, Yoo-Keun; Jung, Woo-Sik

In order to incorporate correctly the large or local scale circulation in the model, a nudging term is introduced into the equation of motion. Nudging effects should be included properly in the model to reduce the uncertainties and improve the air flow field. To improve the meteorological components, the nudging coefficient should perform the adequate influence on complex area for the model initialization technique which related to data reliability and error suppression. Several numerical experiments have been undertaken in order to evaluate the effects on air quality modeling by comparing the performance of the meteorological result with variable nudging coefficient experiment. All experiments are calculated by the upper wind conditions (synoptic or asynoptic condition), respectively. Consequently, it is important to examine the model response to nudging effect of wind and mass information. The MM5-CMAQ model was used to assess the ozone differences in each case, during the episode day in Seoul, Korea and we revealed that there were large differences in the ozone concentration for each run. These results suggest that for the appropriate simulation of large or small-scale circulations, nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, so appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. The statistical verifications showed that adequate nudging coefficient for both wind and temperature data throughout the model had a consistently positive impact on the atmospheric and air quality field. On the case dominated by large-scale circulation, a large nudging coefficient shows a minor improvement in the atmospheric and air quality field. However, when small-scale convection is present, the large nudging coefficient produces consistent improvement in the atmospheric and air quality field.

The role of SST on the South American atmospheric circulation during January, February and March 2001

NASA Astrophysics Data System (ADS)

Drumond, Anita Rodrigues De Moraes; Ambrizzi, Tércio

2005-06-01

Precipitation deficits were observed over southeastern, northeastern and Central Brazil during the 2001 Austral Summer. They contributed to the worsening of the energy crisis that was occurring in the country. A low-level anomalous anticyclonic circulation observed over eastern Brazil enhanced the deviation of moisture transport that usually occurs from the Amazon Basin to southeastern Brazil and inhibited the occurrence of South Atlantic Convergence Zone events in that period. However, an anomalous low-level northerly moisture flux was observed over the La Plata Basin, and positive precipitation anomalies occurred over Bolivia, Paraguay, northeastern Argentina and southern Brazil. Using the ensemble technique, a numerical study was carried out to investigate the role of different sea surface temperature (SST) forcings observed over this anomalous South American atmospheric circulation. Reynolds SST monthly means were used as boundary conditions to study the influence of South Atlantic, South Indian, South Pacific and Equatorial Pacific oceans. The simulations were run from September 2000 to April 2001 using the Community Climate Model version 3.6 General Circulation Model. Ten integrations using different initial conditions were done to each experiment. Numerical experiments suggested that the combined influence of South Pacific and Equatorial Pacific oceans could be responsible for the drought observed over Central Brazil. These experiments simulated the low-level anticyclonic anomaly observed over eastern Brazil. However, both experiments have poorly reproduced the intensity of the anomalous low-level northerly moisture flux observed over the La Plata Basin. Therefore, the intensity of the simulated precipitation anomalies over the subtropical regions was much weaker than observed.

Experimental Observation of Fermi-Pasta-Ulam Recurrence in a Nonlinear Feedback Ring System

NASA Astrophysics Data System (ADS)

Wu, Mingzhong; Patton, Carl E.

2007-01-01

Fermi-Pasta-Ulam recurrence through soliton dynamics has been realized. The experiment used a magnetic film strip-based active feedback ring. At some ring gain level, a wide spin wave pulse is self-generated in the ring. As the pulse circulates, it separates into two envelop solitons with different speeds. When the fast soliton catches up and collides with the slow soliton, the initial wide pulse is perfectly reconstructed. The repetition of this process leads to periodic recurrences of the initial pulse.

Spice: Southwest Pacific Ocean Circulation and Climate Experiment

NASA Astrophysics Data System (ADS)

Ganachaud, A. S.; Melet, A.; Maes, C.

2010-12-01

South Pacific oceanic waters are carried from the subtropical gyre centre in the westward flowing South Equatorial Current (SEC), towards the southwest Pacific-a major circulation pathway that redistributes water from the subtropics to the equator and Southern Ocean. The transit in the Coral Sea is potentially of great importance to tropical climate prediction because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate ENSO and produce basin-scale climate feedbacks. The south branch is associated with comparable impacts in the Tasman Sea area. The Southwest Pacific is a region of complex circulation, with the SEC splitting in strong zonal jets upon encountering island archipelagos. Those jets partition on the Australian eastern boundary to feed the East Australian Current for the southern branch and the North Queensland Current and eventually the Equatorial Undercurrent for the northern branch. On average, the oceanic circulation is driven by the Trade Winds, and subject to substantial variability, related with the South Pacific Convergence Zone (SPCZ) position and intensity. The circulation, and its influence on remote and regional climate, is poorly understood due to the lack of appropriate measurements. Ocean and atmosphere scientists from Australia, France, New Zealand, the United States and Pacific Island countries initiated an international research project under the auspices of CLIVAR to comprehend the southwest Pacific Ocean circulation and its direct and indirect influence on the climate and environment. SPICE is a regionally-coordinated experiment to measure, study and monitor the ocean circulation and the SPCZ, to validate and improve numerical models, and to integrate with assimilating systems. This ongoing project reflects a strong sense that substantial progress can be made through collaboration among South Pacific national research groups, coordinated with broader South Pacific projects.

Social Regulation of Leukocyte Homeostasis: The Role of Glucocorticoid Sensitivity

PubMed Central

Cole, Steve W.

2010-01-01

Recent small-scale genomics analyses suggest that physiologic regulation of pro-inflammatory gene expression by endogenous glucocorticoids may be compromised in individuals who experience chronic social isolation. This could potentially contribute to the elevated prevalence of inflammation-related disease previously observed in social isolates. The present study assessed the relationship between leukocyte distributional sensitivity to glucocorticoid regulation and subjective social isolation in a large population-based sample of older adults. Initial analyses confirmed that circulating neutrophil percentages were elevated, and circulating lymphocyte and monocyte percentages were suppressed, in direct proportion to circulating cortisol levels. However, leukocyte distributional sensitivity to endogenous glucocorticoids was abrogated in individuals reporting either occasional or frequent experiences of subjective social isolation. This finding held in both nonparametric univariate analyses and in multivariate linear models controlling for a variety of biological, social, behavioral, and psychological confounders. The present results suggest that social factors may alter immune cell sensitivity to physiologic regulation by the hypothalamic-pituitary-adrenal axis in ways that could ultimately contribute to the increased physical health risks associated with social isolation. PMID:18394861

Flow reversal and thermal limit in a heated rectangular channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, L.Y.; Tichler, P.R.; Yang, B.W.

The thermal limit in a vertical rectangular channel was determined in a series of experiments whereby the internal coolant underwent a change in flow direction from forced downflow to upward natural circulation. The tests were designed to simulate the flow reversal transient in the High Flux Beam Reactor. A number of parameters were varied in the flow reversal experiments to examine their effects on the thermal limit. Among the parameters varied were the rate of flow coastdown, inlet subcooling, water level in the upper plenum, bypass ratio (ratio of initial flow through the heated section to initial flow through themore » bypass orifice), and single- verses double-sided heating.« less

Results of the US contribution to the joint US/USSR Bering Sea experiment. [atmospheric circulation and sea ice cover

NASA Technical Reports Server (NTRS)

Campbell, W. J.; Chang, T. C.; Fowler, M. G.; Gloersen, P.; Kuhn, P. M.; Ramseier, R. O.; Ross, D. B.; Stambach, G.; Webster, W. J., Jr.; Wilheit, T. T.

1974-01-01

The atmospheric circulation which occurred during the Bering Sea Experiment, 15 February to 10 March 1973, in and around the experiment area is analyzed and related to the macroscale morphology and dynamics of the sea ice cover. The ice cover was very complex in structure, being made up of five ice types, and underwent strong dynamic activity. Synoptic analyses show that an optimum variety of weather situations occurred during the experiment: an initial strong anticyclonic period (6 days), followed by a period of strong cyclonic activity (6 days), followed by weak anticyclonic activity (3 days), and finally a period of weak cyclonic activity (4 days). The data of the mesoscale test areas observed on the four sea ice option flights, and ship weather, and drift data give a detailed description of mesoscale ice dynamics which correlates well with the macroscale view: anticyclonic activity advects the ice southward with strong ice divergence and a regular lead and polynya pattern; cyclonic activity advects the ice northward with ice convergence, or slight divergence, and a random lead and polynya pattern.

Cytometric comparisons between circulating tumor cells from prostate cancer patients and the prostate-tumor-derived LNCaP cell line

NASA Astrophysics Data System (ADS)

Lazar, Daniel C.; Cho, Edward H.; Luttgen, Madelyn S.; Metzner, Thomas J.; Loressa Uson, Maria; Torrey, Melissa; Gross, Mitchell E.; Kuhn, Peter

2012-02-01

Many important experiments in cancer research are initiated with cell line data analysis due to the ease of accessibility and utilization. Recently, the ability to capture and characterize circulating tumor cells (CTCs) has become more prevalent in the research setting. This ability to detect, isolate and analyze CTCs allows us to directly compare specific protein expression levels found in patient CTCs to cell lines. In this study, we use immunocytochemistry to compare the protein expression levels of total cytokeratin (CK) and androgen receptor (AR) in CTCs and cell lines from patients with prostate cancer to determine what translational insights might be gained through the use of cell line data. A non-enrichment CTC detection assay enables us to compare cytometric features and relative expression levels of CK and AR by indirect immunofluorescence from prostate cancer patients against the prostate cancer cell line LNCaP. We measured physical characteristics of these two groups and observed significant differences in cell size, fluorescence intensity and nuclear to cytoplasmic ratio. We hope that these experiments will initiate a foundation to allow cell line data to be compared against characteristics of primary cells from patients.

75 FR 5847 - Section 5309 Bus and Bus Facilities Livability Initiative and Urban Circulator Program Grants

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-04

... Livability Initiative and Urban Circulator Program Grants AGENCY: Federal Transit Administration (FTA), DOT. ACTION: Notice to Extend Application Deadline for the Bus and Bus Facilities and Urban Circulator..., Transportation Equity Act: A Legacy for Users (SAFETEA-LU), Public Law 109-59, August 10, 2005. The Urban...

Numerical Simulation Applications in the Design of EGS Collab Experiment 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, Henry; White, Mark D.; Fu, Pengcheng

The United States Department of Energy, Geothermal Technologies Office (GTO) is funding a collaborative investigation of enhanced geothermal systems (EGS) processes at the meso-scale. This study, referred to as the EGS Collab project, is a unique opportunity for scientists and engineers to investigate the creation of fracture networks and circulation of fluids across those networks under in-situ stress conditions. The EGS Collab project is envisioned to comprise three experiments and the site for the first experiment is on the 4850 Level (4,850 feet below ground surface) in phyllite of the Precambrian Poorman formation, at the Sanford Underground Research Facility, locatedmore » at the former Homestake Gold Mine, in Lead, South Dakota. Principal objectives of the project are to develop a number of intermediate-scale field sites and to conduct well-controlled in situ experiments focused on rock fracture behavior and permeability enhancement. Data generated during these experiments will be compared against predictions of a suite of computer codes specifically designed to solve problems involving coupled thermal, hydrological, geomechanical, and geochemical processes. Comparisons between experimental and numerical simulation results will provide code developers with direction for improvements and verification of process models, build confidence in the suite of available numerical tools, and ultimately identify critical future development needs for the geothermal modeling community. Moreover, conducting thorough comparisons of models, modelling approaches, measurement approaches and measured data, via the EGS Collab project, will serve to identify techniques that are most likely to succeed at the Frontier Observatory for Research in Geothermal Energy (FORGE), the GTO's flagship EGS research effort. As noted, outcomes from the EGS Collab project experiments will serve as benchmarks for computer code verification, but numerical simulation additionally plays an essential role in designing these meso-scale experiments. This paper describes specific numerical simulations supporting the design of Experiment 1, a field test involving hydraulic stimulation of two fractures from notched sections of the injection borehole and fluid circulation between sub-horizontal injection and production boreholes in each fracture individually and collectively, including the circulation of chilled water. Whereas the mine drift allows for accurate and close placement of monitoring instrumentation to the developed fractures, active ventilation in the drift cooled the rock mass within the experimental volume. Numerical simulations were executed to predict seismic events and magnitudes during stimulation, initial fracture orientations for smooth horizontal wellbores, pressure requirements for fracture initiation from notched wellbores, fracture propagation during stimulation between the injection and production boreholes, tracer travel times between the injection and production boreholes, produced fluid temperatures with chilled water injections, pressure limits on fluid circulation to avoid fracture growth, temperature environment surrounding the 4850 Level drift, and fracture propagation within a stress field altered by drift excavation, ventilation cooling, and dewatering.« less

The influence of the ocean circulation state on ocean carbon storage and CO2 drawdown potential in an Earth system model

NASA Astrophysics Data System (ADS)

Ödalen, Malin; Nycander, Jonas; Oliver, Kevin I. C.; Brodeau, Laurent; Ridgwell, Andy

2018-03-01

During the four most recent glacial cycles, atmospheric CO2 during glacial maxima has been lowered by about 90-100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is, however, still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to explore the sensitivity of ocean carbon storage to ocean circulation state. We carry out a set of simulations in which we run the model to pre-industrial equilibrium, but in which we achieve different states of ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. As a consequence, the ensemble members also have different ocean carbon reservoirs, global ocean average temperatures, biological pump efficiencies and conditions for air-sea CO2 disequilibrium. We analyse changes in total ocean carbon storage and separate it into contributions by the solubility pump, the biological pump and the CO2 disequilibrium component. We also relate these contributions to differences in the strength of the ocean overturning circulation. Depending on which ocean forcing parameter is tuned, the origin of the change in carbon storage is different. When wind stress or ocean diapycnal diffusivity is changed, the response of the biological pump gives the most important effect on ocean carbon storage, whereas when atmospheric heat diffusivity or ocean isopycnal diffusivity is changed, the solubility pump and the disequilibrium component are also important and sometimes dominant. Despite this complexity, we obtain a negative linear relationship between total ocean carbon and the combined strength of the northern and southern overturning cells. This relationship is robust to different reservoirs dominating the response to different forcing mechanisms. Finally, we conduct a drawdown experiment in which we investigate the capacity for increased carbon storage by artificially maximising the efficiency of the biological pump in our ensemble members. We conclude that different initial states for an ocean model result in different capacities for ocean carbon storage due to differences in the ocean circulation state and the origin of the carbon in the initial ocean carbon reservoir. This could explain why it is difficult to achieve comparable responses of the ocean carbon pumps in model inter-comparison studies in which the initial states vary between models. We show that this effect of the initial state is quantifiable. The drawdown experiment highlights the importance of the strength of the biological pump in the control state for model studies of increased biological efficiency.

Laser Initiated Ignition of Liquid Propellant

DTIC Science & Technology

1991-01-31

containers held in a water bath of constant temperature 70*C. A larger vessel containing approximately 2ml of propellant was also heated in each experiment and...controller. A stirrer and forced water circulation ensured that all samples were kept at the same temperature. The water wai first heated to the final 5... electrolysed samples. 3 .. .. ....... ......................... volume of 10 ....... . 5 ....... I • . ... .. . .... .. ...... .. . . .. . . ... . .61.8 2 22i

Clusters of circulating tumor cells traverse capillary-sized vessels

PubMed Central

Au, Sam H.; Storey, Brian D.; Moore, John C.; Tang, Qin; Chen, Yeng-Long; Javaid, Sarah; Sarioglu, A. Fatih; Sullivan, Ryan; Madden, Marissa W.; O’Keefe, Ryan; Haber, Daniel A.; Maheswaran, Shyamala; Langenau, David M.; Stott, Shannon L.; Toner, Mehmet

2016-01-01

Multicellular aggregates of circulating tumor cells (CTC clusters) are potent initiators of distant organ metastasis. However, it is currently assumed that CTC clusters are too large to pass through narrow vessels to reach these organs. Here, we present evidence that challenges this assumption through the use of microfluidic devices designed to mimic human capillary constrictions and CTC clusters obtained from patient and cancer cell origins. Over 90% of clusters containing up to 20 cells successfully traversed 5- to 10-μm constrictions even in whole blood. Clusters rapidly and reversibly reorganized into single-file chain-like geometries that substantially reduced their hydrodynamic resistances. Xenotransplantation of human CTC clusters into zebrafish showed similar reorganization and transit through capillary-sized vessels in vivo. Preliminary experiments demonstrated that clusters could be disrupted during transit using drugs that affected cellular interaction energies. These findings suggest that CTC clusters may contribute a greater role to tumor dissemination than previously believed and may point to strategies for combating CTC cluster-initiated metastasis. PMID:27091969

Sensitivity of Boreal-Summer Circulation and Precipitation to Atmospheric Aerosols in Selected Regions: Part I Africa and India

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sud, Yogesh C.; Wilcox, Eric; Lau, William K.

2009-10-23

Version-4 of the Goddard Earth Observing System (GEOS-4) General Circulation Model (GCM) was employed to assess the influence of potential changes in aerosols on the regional circulation, ambient temperatures, and precipitation in four selected regions: India and Africa (current paper), as well as North and South America (companion paper). Ensemble-simulations were carried out with the GCM to assess the aerosol direct and indirect effects, hereafter ADE and AIE. Each simulation was started from the NCEP-analyzed initial conditions for May 1 and was integrated through May-June-July-August of each year: 1982-1987 to provide an ensemble set of six simulations. In the firstmore » set, called the baseline experiment (#1), climatological aerosols were prescribed. The next two experiments (#2 and #3) had two sets of simulations each: one with 2X and another with 1/2X the climatological aerosols over each of the four selected regions. In experiment#2, the anomaly regions were advectively restricted (AR), i.e., the large-scale prognostic fields outside the aerosol anomaly regions were prescribed while in experiment#3, the anomaly regions were advectively Interactive (AI) as is the case in a normal GCM integrations, but with the same aerosols anomalies as in experiment #2. Intercomparisons of circulation, diabatic heating, and precipitation difference fields showed large disparities among the AR and AI simulations, which raised serious questions about the AR assumption, commonly invoked in regional climate simulation studies. Consequently AI simulation mode was chosen for the subsequent studies. Two more experiments (#4 and #5) were performed in the AI mode in which ADE and AIE were activated one at a time. The results showed that ADE and AIE work in concert to make the joint influences larger than sum of each acting alone. Moreover, the ADE and AIE influences were vastly different for the Indian and Africa regions, which suggest an imperative need to include them rationally in climate models. We also found that the aerosol induced increase of tropical cirrus clouds would potentially offset any cirrus thinning that may occur due to global warming in response to CO2 increase.« less

The lagged connection of the positive NAO with the MJO phase 3 in a simplified atmospheric model

NASA Astrophysics Data System (ADS)

Shao, Xiaolu; Song, Jie; Li, Shuanglin

2018-03-01

Based on a simplified nonlinear model and reanalysis data, the lagged connection of the North Atlantic Oscillation (NAO) with the Madden-Julian Oscillation (MJO) in boreal winters is investigated. The positive NAO is observed to occur more frequently about 8-20 days after the onset of the MJO phase 3. A series of heating forcing experiments and initial-value experiments are conducted by utilizing the Geophysical Fluid Dynamics Laboratory (GFDL) dynamical core atmospheric model. The extratropical responses to the tropical heating associated with the MJO phase 3 are characterized by a wave train over the Pacific-North American region with an anticyclone anomaly over the northeastern Pacific and then followed by a positive-NAO-like pattern over the North Atlantic sector. These circulation anomalies generally match the observed lagged-connection well. At the earlier stage, the Rossby wave train excited by the MJO convection propagates into the North Atlantic, leading to a planetary wave anomaly with a low-over-high dipole prior to the positive NAO. At the later stage, the anomalous synoptic eddy vorticity forcing (EVF) streamfunction tendency has a negative-over-positive dipole, which plays a key role in the development of the positive NAO. Further analysis of the initial-value experiments indicates that, for the subsequent formation of the positive NAO, the anomalous circulation over the Indian Ocean aroused by the MJO phase 3 is more crucial than that over the northeastern Pacific.

Month-to-month variability of Indian summer monsoon rainfall in 2016: role of the Indo-Pacific climatic conditions

NASA Astrophysics Data System (ADS)

Chowdary, Jasti S.; Srinivas, G.; Du, Yan; Gopinath, K.; Gnanaseelan, C.; Parekh, Anant; Singh, Prem

2018-03-01

Indian summer monsoon (ISM) rainfall during 2016 exhibited a prominent month-to-month fluctuations over India, with below normal rainfall in June and August and above normal rainfall in July. The factors determining the month-to-month fluctuations in ISM rainfall during 2016 are investigated with main focus on the Indo-Pacific climatic anomalies. Warm sea surface temperature (SST) anomalies associated with super El Niño 2015 disappeared by early summer 2016 over the central and eastern Pacific. On the other hand, negative Indian Ocean dipole (IOD) like SST anomaly pattern over the equatorial Indian Ocean and anomalous anticyclonic circulation over the western North Pacific (WNP) are reported in summer 2016 concurrently with decaying El Niño/developing La Niña phase. Observations revealed that the low rainfall over central north India in June is due to moisture divergence caused by the westward extension of ridge corresponding to WNP anticyclone and subsidence induced by local Hadley cell partly related to negative IOD. Low level convergence of southeasterly wind from Bay of Bengal associated with weak WNP anticyclone and northwesterly wind corresponding to anticyclonic circulation over the northwest India remarkably contributed to positive rainfall in July over most of the Indian subcontinent. While reduced rainfall over the Indian subcontinent in August 2016 is associated with the anomalous moisture transport from ISM region to WNP region, in contrast to July, due to local cyclogenesis corroborated by number of tropical cyclones in the WNP. In addition to this, subsidence related to strong convection supported by cyclonic circulation over the WNP also resulted in low rainfall over the ISM region. Coupled General Circulation model sensitivity experiments confirmed that strong convective activities associated with cyclonic circulation over the WNP is primarily responsible for the observed negative ISM rainfall anomalies in August 2016. It is noted that the Indo-Western Pacific circulation anomalies in August 2016 are well predicted when the coupled model is initiated with initial conditions from end of July and beginning of August compared to May. This analysis suggests the importance of the WNP circulation in forcing strong sub-seasonal/month to month rainfall variations over India.

RhoA-stimulated intra-capillary morphology switch facilitates the arrest of individual circulating tumor cells.

PubMed

Huang, Xi; Yang, Yu; Zhao, Yuwei; Cao, Dan; Ai, Xiaolin; Zeng, Anqi; Gou, Maling; Cai, Lulu; Yang, Hanshuo; Zhao, Chengjian

2018-05-15

Metastasis is the primary cause of death for most cancer patients. Hematogenous arrest of circulating tumor cells (CTCs) is an essential prerequisite for metastases formation. Using transparent transgenic zebrafish (kdrl:eGFP; Casper), together with resonant laser scanning confocal microscopy, we tracked the fate of CTCs in vivo in the blood circulation for days. We found the intra-capillary morphology-switch (ICMS) of individual CTCs from strip to sphere was necessary for their intravascular arrests. Further genetic and pharmacological inhibition experiments indicated that the RhoA signaling was necessary for ICMS and the arrest of CTCs. At last, we demonstrated that early treatment by a clinically approved RhoA/ROCK inhibitor, Fasudil, could efficiently inhibit the initial arrest of individual CTCs and reduce the incidence of tumor metastasis in both zebrafish and mouse models. These results together indicate that RhoA-stimulated ICMS represents a mechanism for the arrest of individual CTCs, providing a potential target for future treatments of hematogenous metastatic disease. © 2017 UICC.

Role of subsurface ocean in decadal climate predictability over the South Atlantic.

PubMed

Morioka, Yushi; Doi, Takeshi; Storto, Andrea; Masina, Simona; Behera, Swadhin K

2018-06-04

Decadal climate predictability in the South Atlantic is explored by performing reforecast experiments using a coupled general circulation model with two initialization schemes; one is assimilated with observed sea surface temperature (SST) only, and the other is additionally assimilated with observed subsurface ocean temperature and salinity. The South Atlantic is known to undergo decadal variability exhibiting a meridional dipole of SST anomalies through variations in the subtropical high and ocean heat transport. Decadal reforecast experiments in which only the model SST is initialized with the observation do not predict well the observed decadal SST variability in the South Atlantic, while the other experiments in which the model SST and subsurface ocean are initialized with the observation skillfully predict the observed decadal SST variability, particularly in the Southeast Atlantic. In-depth analysis of upper-ocean heat content reveals that a significant improvement of zonal heat transport in the Southeast Atlantic leads to skillful prediction of decadal SST variability there. These results demonstrate potential roles of subsurface ocean assimilation in the skillful prediction of decadal climate variability over the South Atlantic.

Stratospheric wind errors, initial states and forecast skill in the GLAS general circulation model

NASA Technical Reports Server (NTRS)

Tenenbaum, J.

1983-01-01

Relations between stratospheric wind errors, initial states and 500 mb skill are investigated using the GLAS general circulation model initialized with FGGE data. Erroneous stratospheric winds are seen in all current general circulation models, appearing also as weak shear above the subtropical jet and as cold polar stratospheres. In this study it is shown that the more anticyclonic large-scale flows are correlated with large forecast stratospheric winds. In addition, it is found that for North America the resulting errors are correlated with initial state jet stream accelerations while for East Asia the forecast winds are correlated with initial state jet strength. Using 500 mb skill scores over Europe at day 5 to measure forecast performance, it is found that both poor forecast skill and excessive stratospheric winds are correlated with more anticyclonic large-scale flows over North America. It is hypothesized that the resulting erroneous kinetic energy contributes to the poor forecast skill, and that the problem is caused by a failure in the modeling of the stratospheric energy cycle in current general circulation models independent of vertical resolution.

Multiphase groundwater flow near cooling plutons

USGS Publications Warehouse

Hayba, D.O.; Ingebritsen, S.E.

1997-01-01

We investigate groundwater flow near cooling plutons with a computer program that can model multiphase flow, temperatures up to 1200??C, thermal pressurization, and temperature-dependent rock properties. A series of experiments examines the effects of host-rock permeability, size and depth of pluton emplacement, single versus multiple intrusions, the influence of a caprock, and the impact of topographically driven groundwater flow. We also reproduce and evaluate some of the pioneering numerical experiments on flow around plutons. Host-rock permeability is the principal factor influencing fluid circulation and heat transfer in hydrothermal systems. The hottest and most steam-rich systems develop where permeability is of the order of 10-15 m2. Temperatures and life spans of systems decrease with increasing permeability. Conduction-dominated systems, in which permeabilities are ???10-16m2, persist longer but exhibit relatively modest increases in near-surface temperatures relative to ambient conditions. Pluton size, emplacement depth, and initial thermal conditions have less influence on hydrothermal circulation patterns but affect the extent of boiling and duration of hydrothermal systems. Topographically driven groundwater flow can significantly alter hydrothermal circulation; however, a low-permeability caprock effectively decouples the topographically and density-driven systems and stabilizes the mixing interface between them thereby defining a likely ore-forming environment.

The sensitivity of numerically simulated climates to land-surface boundary conditions

NASA Technical Reports Server (NTRS)

Mintz, Y.

1982-01-01

Eleven sensitivity experiments that were made with general circulation models to see how land-surface boundary conditions can influence the rainfall, temperature, and motion fields of the atmosphere are discussed. In one group of experiments, different soil moistures or albedos are prescribed as time-invariant boundary conditions. In a second group, different soil moistures or different albedos are initially prescribed, and the soil moisture (but not the albedo) is allowed to change with time according to the governing equations for soil moisture. In a third group, the results of constant versus time-dependent soil moistures are compared.

Examples of data assimilation in mesoscale models

NASA Technical Reports Server (NTRS)

Carr, Fred; Zack, John; Schmidt, Jerry; Snook, John; Benjamin, Stan; Stauffer, David

1993-01-01

The keynote address was the problem of physical initialization of mesoscale models. The classic purpose of physical or diabatic initialization is to reduce or eliminate the spin-up error caused by the lack, at the initial time, of the fully developed vertical circulations required to support regions of large rainfall rates. However, even if a model has no spin-up problem, imposition of observed moisture and heating rate information during assimilation can improve quantitative precipitation forecasts, especially early in the forecast. The two key issues in physical initialization are the choice of assimilating technique and sources of hydrologic/hydrometeor data. Another example of data assimilation in mesoscale models was presented in a series of meso-beta scale model experiments with and 11 km version of the MASS model designed to investigate the sensitivity of convective initiation forced by thermally direct circulations resulting from differential surface heating to four dimensional assimilation of surface and radar data. The results of these simulations underscore the need to accurately initialize and simulate grid and sub-grid scale clouds in meso- beta scale models. The status of the application of the CSU-RAMS mesoscale model by the NOAA Forecast Systems Lab for producing real-time forecasts with 10-60 km mesh resolutions over (4000 km)(exp 2) domains for use by the aviation community was reported. Either MAPS or LAPS model data are used to initialize the RAMS model on a 12-h cycle. The use of MAPS (Mesoscale Analysis and Prediction System) model was discussed. Also discussed was the mesobeta-scale data assimilation using a triply-nested nonhydrostatic version of the MM5 model.

Sensitivities of Summertime Mesoscale Circulations in the Coastal Carolinas to Modifications of the Kain–Fritsch Cumulus Parameterization

EPA Science Inventory

Two mesoscale circulations, the Sandhills circulation and the sea breeze, influence the initiation of deep convection over the Sandhills and the coast in the Carolinas during the summer months. The interaction of these two circulations causes additional convection in this coastal...

Numerical Investigation of the Middle Atlantic Bight Shelfbreak Frontal Circulation Using a High-Resolution Ocean Hindcast Model

DTIC Science & Technology

2010-05-01

circulation from December 2003 to June 2008 . The model is driven by tidal harmonics, realistic atmospheric forcing, and dynamically consistent initial and open...important element of the regional circulation (He and Wilkin 2006). We applied the method of Mellor and Yamada (1982) to compute vertical turbulent...shelfbreak ROMS hindcast ran continuously from December 2003 through January 2008 . Initial conditions were taken from the MABGOM ROMS simulation on 1

Overview of experiment design and comparison of models participating in phase 1 of the SPARC Quasi-Biennial Oscillation initiative (QBOi)

NASA Astrophysics Data System (ADS)

Butchart, Neal; Anstey, James A.; Hamilton, Kevin; Osprey, Scott; McLandress, Charles; Bushell, Andrew C.; Kawatani, Yoshio; Kim, Young-Ha; Lott, Francois; Scinocca, John; Stockdale, Timothy N.; Andrews, Martin; Bellprat, Omar; Braesicke, Peter; Cagnazzo, Chiara; Chen, Chih-Chieh; Chun, Hye-Yeong; Dobrynin, Mikhail; Garcia, Rolando R.; Garcia-Serrano, Javier; Gray, Lesley J.; Holt, Laura; Kerzenmacher, Tobias; Naoe, Hiroaki; Pohlmann, Holger; Richter, Jadwiga H.; Scaife, Adam A.; Schenzinger, Verena; Serva, Federico; Versick, Stefan; Watanabe, Shingo; Yoshida, Kohei; Yukimoto, Seiji

2018-03-01

The Stratosphere-troposphere Processes And their Role in Climate (SPARC) Quasi-Biennial Oscillation initiative (QBOi) aims to improve the fidelity of tropical stratospheric variability in general circulation and Earth system models by conducting coordinated numerical experiments and analysis. In the equatorial stratosphere, the QBO is the most conspicuous mode of variability. Five coordinated experiments have therefore been designed to (i) evaluate and compare the verisimilitude of modelled QBOs under present-day conditions, (ii) identify robustness (or alternatively the spread and uncertainty) in the simulated QBO response to commonly imposed changes in model climate forcings (e.g. a doubling of CO2 amounts), and (iii) examine model dependence of QBO predictability. This paper documents these experiments and the recommended output diagnostics. The rationale behind the experimental design and choice of diagnostics is presented. To facilitate scientific interpretation of the results in other planned QBOi studies, consistent descriptions of the models performing each experiment set are given, with those aspects particularly relevant for simulating the QBO tabulated for easy comparison.

The influence of land surface properties on Sahel climate. Part 1: Desertification

NASA Technical Reports Server (NTRS)

Xue, Yongkang; Shukla, Jagadish

1993-01-01

This is a general circulation model sensitivity study of the physical mechanisms of the effects of desertification on the Sahel drought. The model vegetation types were changed in the prescribed desertification area, which led to changes in the surface characteristics. The model was integrated for three months (June, July, August) with climatological surface conditions (control) and desertification conditions (anomaly) to examine the summer season response to the changed surface conditions. The control and anomaly experiments consisted of five pairs of integrations with different initial conditions and/or sea surface temperature boundary conditions. In the desertification experiment, the moisture flux convergence and rainfall were reduced in the test area and increased to the immediate south of this area. The simulated anomaly dipole pattern was similar to the observed African drought patterns in which the axis of the maximum rainfall shifts to the south. The circulation changes in the desertification experiment were consistent with those observed during sub-Saharan dry years. The tropical easterly jet was weaker and the African easterly jet was stronger than normal. Further, in agreement with the observations, the easterly wave disturbances were reduced in intensity but not in number. Descending motion dominated the desertification area. The surface energy budget and hydrological cycle were also changed substantially in the anomaly experiment.

Impact of four-dimensional data assimilation (FDDA) on urban climate analysis

NASA Astrophysics Data System (ADS)

Pan, Linlin; Liu, Yubao; Liu, Yuewei; Li, Lei; Jiang, Yin; Cheng, Will; Roux, Gregory

2015-12-01

This study investigates the impact of four-dimensional data assimilation (FDDA) on urban climate analysis, which employs the NCAR (National Center for Atmospheric Research) WRF (the weather research and forecasting model) based on climate FDDA (CFDDA) technology to develop an urban-scale microclimatology database for the Shenzhen area, a rapidly developing metropolitan located along the southern coast of China, where uniquely high-density observations, including ultrahigh-resolution surface AWS (automatic weather station) network, radio sounding, wind profilers, radiometers, and other weather observation platforms, have been installed. CFDDA is an innovative dynamical downscaling regional climate analysis system that assimilates diverse regional observations; and has been employed to produce a 5 year multiscale high-resolution microclimate analysis by assimilating high-density observations at Shenzhen area. The CFDDA system was configured with four nested-grid domains at grid sizes of 27, 9, 3, and 1 km, respectively. This research evaluates the impact of assimilating high-resolution observation data on reproducing the refining features of urban-scale circulations. Two experiments were conducted with a 5 year run using CFSR (climate forecast system reanalysis) as boundary and initial conditions: one with CFDDA and the other without. The comparisons of these two experiments with observations indicate that CFDDA greatly reduces the model analysis error and is able to realistically analyze the microscale features such as urban-rural-coastal circulation, land/sea breezes, and local-hilly terrain thermal circulations. It is demonstrated that the urbanization can produce 2.5 k differences in 2 m temperatures, delays/speeds up the land/sea breeze development, and interacts with local mountain-valley circulations.

Library Specifications for a New Circulation System for Concordia University Libraries.

ERIC Educational Resources Information Center

Tallon, James

This study of library requirements for a new circulation system is organized into three sections: (1) items required for initial implementation in July 1982; (2) items relating to notice generation and activity statistics, with implementation expected by fall 1982; and (3) items provided in the system as initially implemented, with additional…

Time-resolved particle image velocimetry measurements of the 3D single-mode Richtmyer-Meshkov instability

NASA Astrophysics Data System (ADS)

Xu, Qian

The Richtmyer-Meshkov Instability (RMI) (Commun. Pure Appl. Math 23, 297-319, 1960; Izv. Akad. Nauk. SSSR Maekh. Zhidk. Gaza. 4, 151-157, 1969) occurs due to an impulsive acceleration acting on a perturbed interface between two fluids of different densities. In the experiments presented in this thesis, single mode 3D RMI experiments are performed. An oscillating speaker generates a single mode sinusoidal initial perturbation at an interface of two gases, air and SF6. A Mach 1.19 shock wave accelerates the interface and generates the Richtmyer-Meshkov Instability. Both gases are seeded with propylene glycol particles which are illuminated by an Nd: YLF pulsed laser. Three high-speed video cameras record image sequences of the experiment. Particle Image Velocimetry (PIV) is applied to measure the velocity field. Measurements of the amplitude for both spike and bubble are obtained, from which the growth rate is measured. For both spike and bubble experiments, amplitude and growth rate match the linear stability theory at early time, but fall into a non-linear region with amplitude measurements lying between the modified 3D Sadot et al. model ( Phys. Rev. Lett. 80, 1654-1657, 1998) and the Zhang & Sohn model (Phys. Fluids 9. 1106-1124, 1997; Z. Angew. Math Phys 50. 1-46, 1990) at late time. Amplitude and growth rate curves are found to lie above the modified 3D Sadot et al. model and below Zhang & Sohn model for the spike experiments. Conversely, for the bubble experiments, both amplitude and growth rate curves lie above the Zhang & Sohn model, and below the modified 3D Sadot et al. model. Circulation is also calculated using the vorticity and velocity fields from the PIV measurements. The calculated circulation are approximately equal and found to grow with time, a result that differs from the modified Jacobs and Sheeley's circulation model (Phys. Fluids 8, 405-415, 1996).

Measurement of central venous pressure and determination of hormones in blood serum during weightlessness

NASA Technical Reports Server (NTRS)

Kirsch, K.

1981-01-01

A Spacelab experiment is described which proposes to obtain data on the degree of engorgement of the cephalad circulation during weightlessness by recording central venous pressure. Of practical importance is the question of how close the astronauts are to pulmonary edema and whether the pressure falls toward normal during the time of the mission. Another experiment to investigate deviations from normal fluid and mineral metabolism, possibly initiated by the central engorgement of the low pressure system, is discussed. Hormones responsible for the control of water and mineral balance (vasopressin, catecholamines, renin, aldosterone, corticosteroids, and prostaglandin E1) will be analyzed from blood samples.

Hydrological and glaciological balances on Antizana Volcano, Ecuador

NASA Astrophysics Data System (ADS)

Favier, V.; Cadier, E.; Coudrain, A.; Francou, B.; Maisincho, L.; Praderio, E.; Villacis, M.; Wagnon, P.

2006-12-01

Water supply for Quito, the capital of Ecuador, is partly fed by the water collected at the piedmont of Antizana ice covered stratovolcano. In order to assess the contribution of glaciers to the local water resources, a comparison of hydrological and glaciological datasets collected over the 1995-2005 period on Antizana Glacier 15 watershed was realized. Over the study period, Antizana glacier 15 retreated quickly, inducing an important water contribution to lower altitude discharges. However, comparison of hydrological and glaciological balances allowed observation of important missing runoffs due to underground circulations. Subsuperficial circulations were initially questioned due to the total disappearance of surface streams at the level of the frontal moraine, a surface stream being observed again downstream the moraine. Brine injections were performed upstream the moraine and in a small lake located on the moraine and restitution rates of salt were computed. Tracer experiments demonstrated a complete restitution of discharges implying that missing runoff were not involved in subsuperficial circulations but in deeper ones that may have flown through the fractured rock environment of the stratovlocano. Experiments also demonstrated that infiltrations occurred directly at the bedrock of the glaciers. Then, taking into account the weak discharges observed at the glacier front would induce computation of a strongly underestimated value of the actual water contribution from glaciers to lower altitude discharges. Finally, assessing water contribution from glaciers of Ecuador requires a comparison of glaciological and hydrological data.

Model representation of salinity anomalies and the stability of the North Atlantic overturning circulation

NASA Astrophysics Data System (ADS)

Megann, A.; New, A.; Blaker, A.

2012-04-01

Vellinga and Wu (2004) and others have identified feedback cycles governing the decadal variability of the North Atlantic overturning circulation, in which modulation of tropical rainfall creates near-surface salinity anomalies that propagate northward to the winter convection regions, where they affect the wintertime convection through changes in surface density. Freshwater "hosing" experiments, in which 0.1 Sv of extra freshwater is added to the convection region, are described using two climate models: the UK Met Office's HadCM3; and CHIME, which is identical to HadCM3 except for the replacement of the z-coordinate ocean component of HadCM3 with the hybrid isopycnic model HYCOM. While HadCM3 shows an unambiguous weakening of the meridional overturning circulation (MOC) by 5 Sv, the MOC in CHIME initially starts to decrease but returns to a value close to that in the control experiment after 40-50 years even though the hosing flux is still being applied. It will be shown that the recovery of the overturning in CHIME is mainly due to enhanced advective transport of salt from the subtropics by salinity anomalies. These are found to be substantially more coherent meridionally in CHIME than in HadCM3, consistent with the known superior ability of the isopycnic model formulation to preserve watermass properties over long distances.

Experiments on Thermal Convection in Rotating Spherical Shells With Radial Gravity: The Geophysical Fluid Flow Cell

NASA Technical Reports Server (NTRS)

Hart, John E.

1996-01-01

Experiments designed to study the fluid dynamics of buoyancy driven circulations in rotating spherical shells were conducted on the United States Microgravity Laboratory 2 spacelab mission. These experiments address several aspects of prototypical global convection relevant to large scale motions on the Sun, Earth, and on the giant planets. The key feature is the consistent modeling of radially directed gravity in spherical geometry by using dielectric polarization forces. Imagery of the planforms of thermally driven flows for rapidly-rotating regimes shows an initial separation and eventual merger of equatorial and polar convection as the heating (i.e. the Rayleigh number) is increased. At low rotation rates, multiple-states of motion for the same external parameters were observed.

Global Observations and Understanding of the General Circulation of the Oceans

NASA Technical Reports Server (NTRS)

1984-01-01

The workshop was organized to: (1) assess the ability to obtain ocean data on a global scale that could profoundly change our understanding of the circulation; (2) identify the primary and secondary elements needed to conduct a World Ocean Circulation Experiment (WOCE); (3) if the ability is achievable, to determine what the U.S. role in such an experiment should be; and (4) outline the steps necessary to assure that an appropriate program is conducted. The consensus of the workshop was that a World Ocean Circulation Experiment appears feasible, worthwhile, and timely. Participants did agree that such a program should have the overall goal of understanding the general circulation of the global ocean well enough to be able to predict ocean response and feedback to long-term changes in the atmosphere. The overall goal, specific objectives, and recommendations for next steps in planning such an experiment are included.

Computational Study of the Richtmyer-Meshkov Instability with a Complex Initial Condition

NASA Astrophysics Data System (ADS)

McFarland, Jacob; Reilly, David; Greenough, Jeffrey; Ranjan, Devesh

2014-11-01

Results are presented for a computational study of the Richtmyer-Meshkov instability with a complex initial condition. This study covers experiments which will be conducted at the newly-built inclined shock tube facility at the Georgia Institute of Technology. The complex initial condition employed consists of an underlying inclined interface perturbation with a broadband spectrum of modes superimposed. A three-dimensional staggered mesh arbitrary Lagrange Eulerian (ALE) hydrodynamics code developed at Lawerence Livermore National Laboratory called ARES was used to obtain both qualitative and quantitative results. Qualitative results are discussed using time series of density plots from which mixing width may be extracted. Quantitative results are also discussed using vorticity fields, circulation components, and energy spectra. The inclined interface case is compared to the complex interface case in order to study the effect of initial conditions on shocked, variable-density flows.

Numerical Simulation and Sensitivity Analysis of Subglacial Meltwater Plumes: Implications for Ocean-Glacier Coupling in Rink Isbrae, West Greenland

NASA Astrophysics Data System (ADS)

Carroll, D.; Sutherland, D.; Shroyer, E.; Nash, J. D.

2014-12-01

The rate of mass loss from the Greenland Ice Sheet quadrupled over the last two decades and may be due in part to changes in ocean heat transport to marine-terminating outlet glaciers. Meltwater commonly discharges at the grounding line in these outlet glacier fjords, generating a turbulent upwelling plume that separates from the glacier face when it reaches neutral density. This mechanism is the current paradigm for setting the magnitude of net heat transport in Greenland's glacial fjords. However, sufficient observations of meltwater plumes are not available to test the buoyancy-driven circulation hypothesis. Here, we use an ocean general circulation model (MITgcm) of the near-glacier field to investigate how plume water properties, terminal height, centerline velocity and volume transport depend on the initial conditions and numerical parameter choices in the model. These results are compared to a hydrodynamic mixing model (CORMIX), typically used in civil engineering applications. Experiments using stratification profiles from the continental shelf quantify the errors associated with using far-field observatons to initialize near-glacier plume models. The plume-scale model results are then integrated with a 3-D fjord-scale model of the Rink Isbrae glacier/fjord system in west Greenland. We find that variability in the near-glacier plume structure can strongly control the resulting fjord-scale circulation. The fjord model is forced with wind and tides to examine how oceanic and atmospheric forcing influence net heat transport to the glacier.

Proceedings of the Circulation-Control Workshop, 1986

NASA Technical Reports Server (NTRS)

Nielsen, Jack N. (Compiler)

1987-01-01

A Circulation Control Workshop was held at NASA Ames by respresentatives of academia, industry, and government. A total of 32 papers were given in six technical sessions covering turbulence, circulation control airfoil theory, circulation control airfoil wing experiments, circulation control rotor theory, x-wing technology, fixed wing technology, and other concepts. The last session of the workshop was devoted to circulation control research planning.

Monthly mean forecast experiments with the GISS model

NASA Technical Reports Server (NTRS)

Spar, J.; Atlas, R. M.; Kuo, E.

1976-01-01

The GISS general circulation model was used to compute global monthly mean forecasts for January 1973, 1974, and 1975 from initial conditions on the first day of each month and constant sea surface temperatures. Forecasts were evaluated in terms of global and hemispheric energetics, zonally averaged meridional and vertical profiles, forecast error statistics, and monthly mean synoptic fields. Although it generated a realistic mean meridional structure, the model did not adequately reproduce the observed interannual variations in the large scale monthly mean energetics and zonally averaged circulation. The monthly mean sea level pressure field was not predicted satisfactorily, but annual changes in the Icelandic low were simulated. The impact of temporal sea surface temperature variations on the forecasts was investigated by comparing two parallel forecasts for January 1974, one using climatological ocean temperatures and the other observed daily ocean temperatures. The use of daily updated sea surface temperatures produced no discernible beneficial effect.

Transport of cargo from periphery to brain by circulating monocytes.

PubMed

Cintron, Amarallys F; Dalal, Nirjari V; Dooyema, Jeromy; Betarbet, Ranjita; Walker, Lary C

2015-10-05

The misfolding and aggregation of the Aβ peptide - a fundamental event in the pathogenesis of Alzheimer׳s disease - can be instigated in the brains of experimental animals by the intracranial infusion of brain extracts that are rich in aggregated Aβ. Recent experiments have found that the peripheral (intraperitoneal) injection of Aβ seeds induces Aβ deposition in the brains of APP-transgenic mice, largely in the form of cerebral amyloid angiopathy. Macrophage-type cells normally are involved in pathogen neutralization and antigen presentation, but under some circumstances, circulating monocytes have been found to act as vectors for the transport of pathogenic agents such as viruses and prions. The present study assessed the ability of peripheral monocytes to transport Aβ aggregates from the peritoneal cavity to the brain. Our initial experiments showed that intravenously delivered macrophages that had previously ingested fluorescent nanobeads as tracers migrate primarily to peripheral organs such as spleen and liver, but that a small number also reach the brain parenchyma. We next injected CD45.1-expressing monocytes from donor mice intravenously into CD45.2-expressing host mice; after 24h, analysis by fluorescence-activated cell sorting (FACS) and histology confirmed that some CD45.1 monocytes enter the brain, particularly in the superficial cortex and around blood vessels. When the donor monocytes are first exposed to Aβ-rich brain extracts from human AD cases, a subset of intravenously delivered Aβ-containing cells migrate to the brain. These experiments indicate that, in mouse models, circulating monocytes are potential vectors by which exogenously delivered, aggregated Aβ travels from periphery to brain, and more generally support the hypothesis that macrophage-type cells can participate in the dissemination of proteopathic seeds. Copyright © 2015 Elsevier B.V. All rights reserved.

Experimental Study of Shock-Induced Compression and Vortex Generation in the Shock-Bubble Interaction

NASA Astrophysics Data System (ADS)

Ranjan, Devesh; Motl, Bradley; Niederhaus, John; Oakley, Jason; Anderson, Mark; Bonazza, Riccardo; Greenough, Jeffrey

2006-11-01

Results are presented from experiments studying the interaction of a planar shock wave of strength 1.4

Immunity against influenza A(H1N1) infections is determined by age at the time of initial strain circulation.

PubMed

Delabre, R M; Salez, N; Lapidus, N; Lemaitre, M; Leruez-Ville, M; de Lamballerie, X; Carrat, F

2017-01-01

We explored age-dependent patterns in haemagglutination inhibition (HI) titre to seasonal [1956 A(H1N1), 1977 A(H1N1), 2007 A(H1N1)] and pandemic [A(H1N1)pdm09] influenza strains using serological data collected from an adult French influenza cohort. Subjects were recruited by their general practitioners from 2008 to 2009 and followed until 2010. We explored age-related differences between strain-specific HI titres using 1053 serological samples collected over the study period from 398 unvaccinated subjects. HI titres against the tested seasonal and pandemic strains were determined using the HI technique. Geometric mean titres (GMTs) were estimated using regression models for interval-censored data. Generalized additive mixed models were fit to log-transformed HI estimates to study the relationship between HI titre and age (age at inclusion and/or age at initial strain circulation). GMT against one strain was consistently highest in the birth cohort exposed to that strain during childhood, with peak titres observed in subjects aged 7-8 years at the time of initial strain circulation. Our results complete previous findings on influenza A(H3N2) strains and identify a strain-dependent relationship between HI titre and age at initial strain circulation.

Astronomical variation experiments with a Mars general circulation model

NASA Technical Reports Server (NTRS)

Pollack, J. B.; Haberle, R. M.; Murphy, J. R.; Schaeffer, J.; Lee, H.

1992-01-01

In time scales of a hundred thousand to a million years, the eccentricity of Mars orbit varies in a quasi-periodic manner between extremes as large as 0.14 and as small as 0 and the tilt of its axis of rotation with respect to the orbit normal also varies quasi-periodically between extremes as large as 35 deg and as small as 15 deg. In addition, the orientation of the axis precesses on comparable time scales. These astronomical variations are much more extreme than those experienced by the Earth. These variations are thought to have strongly modulated the seasonal cycles of dust, carbon dioxide, and water. One manifestation of the induced quasiperiodic climate changes may be the layered terrain of the polar regions, with individual layers perhaps recording variations in the absolute and/or relative deposition rates of dust and water in the polar regions, most likely in association with the winter time deposition of carbon dioxide ice. In an attempt to understand the manner in which atmospheric temperatures and winds respond to the astronomical forcings, we have initiated a series of numerical experiments with the NASA/Ames general circulation model of the Martian Atmosphere.

Initializing decadal climate predictions over the North Atlantic region

NASA Astrophysics Data System (ADS)

Matei, Daniela Mihaela; Pohlmann, Holger; Jungclaus, Johann; Müller, Wolfgang; Haak, Helmuth; Marotzke, Jochem

2010-05-01

Decadal climate prediction aims to predict the internally-generated decadal climate variability in addition to externally-forced climate change signal. In order to achieve this it is necessary to start the predictions from the current climate state. In this study we investigate the forecast skill of the North Atlantic decadal climate predictions using two different ocean initialization strategies. First we apply an assimilation of ocean synthesis data provided by the GECCO project (Köhl and Stammer, 2008) as initial conditions for the coupled model ECHAM5/MPI-OM. Hindcast experiments are then performed over the period 1952-2001. An alternative approach is one in which the subsurface ocean temperature and salinity are diagnosed from an ensemble of ocean model runs forced by the NCEP-NCAR atmospheric reanalyzes for the period 1948-2007, then nudge into the coupled model to produce initial conditions for the hindcast experiments. An anomaly coupling scheme is used in both approaches to avoid the hindcast drift and the associated initial shock. Differences between the two assimilation approaches are discussed by comparing them with the observational data in key regions and processes. We asses the skill of the initialized decadal hindcast experiments against the prediction skill of the non-initialized hindcasts simulation. We obtain an overview of the regions with the highest predictability from the regional distribution of the anomaly correlation coefficients and RMSE for the SAT. For the first year the hindcast skill is increased over almost all ocean regions in the NCEP-forced approach. This increase in the hindcast skill for the 1 year lead time is somewhat reduced in the GECCO approach. At lead time 5yr and 10yr, the skill enhancement is still found over the North Atlantic and North Pacific regions. We also consider the potential predictability of the Atlantic Meridional Overturning Circulation (AMOC) and Nordic Seas Overflow by comparing the predicted values to the respective assimilation experiments. Hindcasts of Atlantic MOC and Denmark Strait Overflow show higher predictability than the comparison experiments without initialization and damped persistence predictions up to about 5-6 years.

A moderate elevation of circulating levels of IGF-I does not alter ErbB2 induced mammary tumorigenesis

PubMed Central

2011-01-01

Background Epidemiological evidence suggests that moderately elevated levels of circulating insulin-like growth factor-I (IGF-I) are associated with increased risk of breast cancer in women. How circulating IGF-I may promote breast cancer incidence is unknown, however, increased IGF-I signaling is linked to trastuzumab resistance in ErbB2 positive breast cancer. Few models have directly examined the effect of moderately high levels of circulating IGF-I on breast cancer initiation and progression. The purpose of this study was to assess the ability of circulating IGF-I to independently initiate mammary tumorigenesis and/or accelerate the progression of ErbB2 mediated mammary tumor growth. Methods We crossed heterozygous TTR-IGF-I mice with heterozygous MMTV-ErbB2 mice to generate 4 different genotypes: TTR-IGF-I/MMTV-ErbB2 (bigenic), TTR-IGF-I only, MMTV-ErbB2 only, and wild type (wt). Virgin females were palpated twice a week and harvested when tumors reached 1000 mm3. For study of normal development, blood and tissue were harvested at 4, 6 and 9 weeks of age in TTR-IGF-I and wt mice. Results TTR-IGF-I and TTR-IGF-I/ErbB2 bigenic mice showed a moderate 35% increase in circulating total IGF-I compared to ErbB2 and wt control mice. Elevation of circulating IGF-I had no effect upon pubertal mammary gland development. The transgenic increase in IGF-I alone wasn't sufficient to initiate mammary tumorigenesis. Elevated circulating IGF-I had no effect upon ErbB2-induced mammary tumorigenesis or metastasis, with median time to tumor formation being 30 wks and 33 wks in TTR-IGF-I/ErbB2 bigenic and ErbB2 mice respectively (p = 0.65). Levels of IGF-I in lysates from ErbB2/TTR-IGF-I tumors compared to ErbB2 was elevated in a similar manner to the circulating IGF-I, however, there was no effect on the rate of tumor growth (p = 0.23). There were no morphological differences in tumor type (solid adenocarcinomas) between bigenic and ErbB2 mammary glands. Conclusion Using the first transgenic animal model to elevate circulating levels of IGF-I to those comparable to women at increased risk of breast cancer, we showed that moderately high levels of systemic IGF-I have no effect on pubertal mammary gland development, initiating mammary tumorigenesis or promoting ErbB2 driven mammary carcinogenesis. Our work suggests that ErbB2-induced mammary tumorigenesis is independent of the normal variation in circulating levels of IGF-I. PMID:21867536

Simulated forecast error and climate drift resulting from the omission of the upper stratosphere in numerical models

NASA Technical Reports Server (NTRS)

Boville, Byron A.; Baumhefner, David P.

1990-01-01

Using an NCAR community climate model, Version I, the forecast error growth and the climate drift resulting from the omission of the upper stratosphere are investigated. In the experiment, the control simulation is a seasonal integration of a medium horizontal general circulation model with 30 levels extending from the surface to the upper mesosphere, while the main experiment uses an identical model, except that only the bottom 15 levels (below 10 mb) are retained. It is shown that both random and systematic errors develop rapidly in the lower stratosphere with some local propagation into the troposphere in the 10-30-day time range. The random growth rate in the troposphere in the case of the altered upper boundary was found to be slightly faster than that for the initial-condition uncertainty alone. However, this is not likely to make a significant impact in operational forecast models, because the initial-condition uncertainty is very large.

Role of Ocean Initial Conditions to Diminish Dry Bias in the Seasonal Prediction of Indian Summer Monsoon Rainfall: A Case Study Using Climate Forecast System

NASA Astrophysics Data System (ADS)

Koul, Vimal; Parekh, Anant; Srinivas, G.; Kakatkar, Rashmi; Chowdary, Jasti S.; Gnanaseelan, C.

2018-03-01

Coupled models tend to underestimate Indian summer monsoon (ISM) rainfall over most of the Indian subcontinent. Present study demonstrates that a part of dry bias is arising from the discrepancies in Oceanic Initial Conditions (OICs). Two hindcast experiments are carried out using Climate Forecast System (CFSv2) for summer monsoons of 2012-2014 in which two different OICs are utilized. With respect to first experiment (CTRL), second experiment (AcSAL) differs by two aspects: usage of high-resolution atmospheric forcing and assimilation of only ARGO observed temperature and salinity profiles for OICs. Assessment of OICs indicates that the quality of OICs is enhanced due to assimilation of actual salinity profiles. Analysis reveals that AcSAL experiment showed 10% reduction in the dry bias over the Indian land region during the ISM compared to CTRL. This improvement is consistently apparent in each month and is highest for June. The better representation of upper ocean thermal structure of tropical oceans at initial stage supports realistic upper ocean stability and mixing. Which in fact reduced the dominant cold bias over the ocean, feedback to air-sea interactions and land sea thermal contrast resulting better representation of monsoon circulation and moisture transport. This reduced bias of tropospheric moisture and temperature over the Indian land mass and also produced better tropospheric temperature gradient over land as well as ocean. These feedback processes reduced the dry bias in the ISM rainfall. Study concludes that initializing the coupled models with realistic OICs can reduce the underestimation of ISM rainfall prediction.

Initiation Processes of the Tropical Intraseasonal Variability Simulated in an Aqua-Planet Experiment: What is the Intrinsic Mechanism for MJO Onset?

NASA Astrophysics Data System (ADS)

Takasuka, Daisuke; Satoh, Masaki; Miyakawa, Tomoki; Miura, Hiroaki

2018-04-01

To understand the intrinsic onset mechanism of the Madden-Julian Oscillation (MJO), we simulated a set of initiation processes of MJO-like disturbances in 10 year aqua-planet experiments using a global atmospheric model with a 56 km horizontal mesh and an explicit cloud scheme. Under a condition with a zonally nonuniform sea surface temperature (SST) in the tropics, we reproduced MJO-like disturbances over the western warm pool region. The lagged-composite analysis of detected MJO-like disturbances clarifies the time sequence of three-dimensional dynamic and moisture fields prior to the onset. We found that midtropospheric moistening, a condition that is favorable for deep convection, is particularly obvious in the initiation region 5-9 days before onset. The moistening is caused by two-dimensional horizontal advection due to cross-equatorial shallow circulations associated with mixed Rossby-gravity waves, as well as anomalous poleward flows of a negative Rossby response to suppressed convection. When the midtroposphere is sufficiently moistened, lower tropospheric signals of circumnavigating Kelvin waves trigger active convection. The surface latent heat flux (LHF) feedback contributes to the initial stages of convective organization, while the cloud-radiation feedback contributes to later stages. Sensitivity experiments suggest that circumnavigating Kelvin waves regulate the period of MJO-like disturbances because of efficient convective triggering and that the LHF feedback contributes to rapid convective organization. However, the experiments also reveal that both conditions are not necessary for the existence of MJO-like disturbances. Implications for the relevance of these mechanisms for MJO onset are also discussed.

Seasonal Predictions with the GEOS GCM

NASA Technical Reports Server (NTRS)

Schubert, Siegfried; Chang, Yehui; Suarez, Max

1999-01-01

A number of ensembles of seasonal forecasts have recently been completed as part of NASA's Seasonal to Interannual Prediction Project (NSIPP). The focus is on the extratropical response of the atmosphere to observed Surface Sea Temperature (SST) anomalies during boreal winter. The prediction experiments consist of nine forecasts starting from slightly different initial conditions for each year of the 15 year period 1981-95, employing version 2 of the Goddard Earth Observing System (GEOS) atmospheric Global Circulation Models (GCM). The initial conditions are obtained from the NASA GEOS-1 reanalysis data. Comparisons with a companion set of six long-term simulations with observed SST (starting in 1978, so they have no memory of the initial conditions for the periods of interest) are used to assess the relative contributions of the initial conditions and SST anomalies to forecast skill ranging from daily to seasonal time scales. The ensembles are used to isolate the signal, and to assess the nature of the inherent variability (noise) of the forecasts.

Spanwise Spacing Effects on the Initial Structure and Decay of Axial Vortices

NASA Technical Reports Server (NTRS)

Wendt, B. J.; Reichert, B. A.

1996-01-01

The initial structure and axial decay of an array of streamwise vortices embedded in a turbulent pipe boundary layer is experimentally investigated. The vortices are shed in counter-rotating fashion from an array of equally-spaced symmetric airfoil vortex generators. Vortex structure is quantified in terms of crossplane circulation and peak streamwise vorticity. Flow conditions are subsonic and incompressible. The focus of this study is on the effect of the initial spacing between the parent vortex generators. Arrays with vortex generators spaced at 15 and 30 degrees apart are considered. When the spacing between vortex generators is decreased the circulation and peak vorticity of the shed vortices increases. Analysis indicates this strengthening results from regions of fluid acceleration in the vicinity of the vortex generator array. Decreased spacing between the constituent vortices also produces increased rates of circulation and peak vorticity decay.

Initiation of the Immune Response by Extracellular Hsp72: Chaperokine Activity of Hsp72

PubMed Central

Asea, Alexzander

2007-01-01

Heat shock proteins exert their beneficial effects via basically two modes of action depending on their relative location within the host. Intracellular heat shock proteins found within cells serve a cytoprotective role by chaperoning naïve, misfolded and/or denatured proteins in response to stressful stimuli by a process known as the stress response. However, stressful stimuli also induce the release of intracellular heat shock proteins into the extracellular milieu and circulation. The extracellular heat shock protein proteins serve a cytostimulatory role by initiating immune responses designed to fend off microbial infection and destroy neoplastic transformed cells. This review will briefly cover recent advances into elucidating the mechanism(s) by which stress induces the release of heat shock proteins into the circulation, how it initiates immune responses and suggest the possible biological significance of circulating Hsp to the host. PMID:17502920

Initiation of the Immune Response by Extracellular Hsp72: Chaperokine Activity of Hsp72.

PubMed

Asea, Alexzander

2006-08-01

Heat shock proteins exert their beneficial effects via basically two modes of action depending on their relative location within the host. Intracellular heat shock proteins found within cells serve a cytoprotective role by chaperoning naïve, misfolded and/or denatured proteins in response to stressful stimuli by a process known as the stress response. However, stressful stimuli also induce the release of intracellular heat shock proteins into the extracellular milieu and circulation. The extracellular heat shock protein proteins serve a cytostimulatory role by initiating immune responses designed to fend off microbial infection and destroy neoplastic transformed cells. This review will briefly cover recent advances into elucidating the mechanism(s) by which stress induces the release of heat shock proteins into the circulation, how it initiates immune responses and suggest the possible biological significance of circulating Hsp to the host.

The rationale for liquid biopsy in colorectal cancer: a focus on circulating tumor cells.

PubMed

Gazzaniga, Paola; Raimondi, Cristina; Nicolazzo, Chiara; Carletti, Raffaella; di Gioia, Cira; Gradilone, Angela; Cortesi, Enrico

2015-01-01

Capturing circulating tumor cells (CTCs) and/or circulating tumor DNA from blood, which represents a precious source of biological material derived from both primary and metastatic tumors, has been named a 'liquid biopsy'. While the circulating tumor DNA might be more representative of the bulk of the metastatic tumor, CTCs are thought to reflect more of the metastases-initiating cells. Consequently, a liquid biopsy made of tumor cells and tumor DNA that is able to track cancer evolution, as a fingerprint of the patient's individual tumor, and is easy to perform at every stage of the disease course, sounds attractive. This article mainly focuses on the applications of CTCs to track tumor dynamics in real time using colorectal cancer as a model system. The analysis of viable CTCs at DNA, RNA and protein levels, as well as their expansion in vitro, may allow deep investigation of the features of metastases-initiating cells.

Feasibility study: Atmospheric general circulation experiment, volume 2

NASA Technical Reports Server (NTRS)

Homsey, R. J. (Editor)

1981-01-01

The feasibility analysis of the atmospheric general circulation experiment (AGCE) are documented. The analysis performed in each technical area, the rationale and substantiation for the design approaches selected for the hardware, and the design details for the baseline AGCE are presented.

Role of a cumulus parameterization scheme in simulating atmospheric circulation and rainfall in the nine-layer Goddard Laboratory for Atmospheres General Circulation Model

NASA Technical Reports Server (NTRS)

Sud, Y. C.; Chao, Winston C.; Walker, G. K.

1992-01-01

The influence of a cumulus convection scheme on the simulated atmospheric circulation and hydrologic cycle is investigated by means of a coarse version of the GCM. Two sets of integrations, each containing an ensemble of three summer simulations, were produced. The ensemble sets of control and experiment simulations are compared and differentially analyzed to determine the influence of a cumulus convection scheme on the simulated circulation and hydrologic cycle. The results show that cumulus parameterization has a very significant influence on the simulation circulation and precipitation. The upper-level condensation heating over the ITCZ is much smaller for the experiment simulations as compared to the control simulations; correspondingly, the Hadley and Walker cells for the control simulations are also weaker and are accompanied by a weaker Ferrel cell in the Southern Hemisphere. Overall, the difference fields show that experiment simulations (without cumulus convection) produce a cooler and less energetic atmosphere.

South Atlantic Ocean circulation: Simulation experiments with a quasi-geostrophic model and assimilation of TOPEX/POSEIDON and ERS 1 altimeter data

NASA Astrophysics Data System (ADS)

Florenchie, P.; Verron, J.

1998-10-01

Simulation experiments of South Atlantic Ocean circulations are conducted with a 1/6°, four-layered, quasi-geostrophic model. By means of a simple nudging data assimilation procedure along satellite tracks, TOPEX/POSEIDON and ERS 1 altimeter measurements are introduced into the model to control the simulation of the basin-scale circulation for the period from October 1992 to September 1994. The model circulation appears to be strongly influenced by the introduction of altimeter data, offering a consistent picture of South Atlantic Ocean circulations. Comparisons with observations show that the assimilating model successfully simulates the kinematic behavior of a large number of surface circulation components. The assimilation procedure enables us to produce schematic diagrams of South Atlantic circulation in which patterns ranging from basin-scale currents to mesoscale eddies are portrayed in a realistic way, with respect to their complexity. The major features of the South Atlantic circulation are described and analyzed, with special emphasis on the Brazil-Malvinas Confluence region, the Subtropical Gyre with the formation of frontal structures, and the Agulhas Retroflection. The Agulhas eddy-shedding process has been studied extensively. Fourteen eddies appear to be shed during the 2-year experiment. Because of their strong surface topographic signature, Agulhas eddies have been tracked continuously during the assimilation experiment as they cross the South Atlantic basin westward. Other effects of the assimilation procedure are shown, such as the intensification of the Subtropical Gyre, the appearance of a strong seasonal cycle in the Brazil Current transport, and the increase of the mean Brazil Current transport. This last result, combined with the westward oriention of the Agulhas eddies' trajectories, leads to a southward transport of mean eddy kinetic energy across 30°S.

Influence of Offshore Initial Moisture Field and Convection on the Development of Coastal Convection in a Heavy Rainfall Event over South China during the Pre-summer Rainy Season

NASA Astrophysics Data System (ADS)

Lu, Rong; Sun, Jianhua; Fu, Shenming

2017-04-01

This paper utilizes the observation data from the Southern China Monsoon Rainfall Experiment (SCMREX) and the numerical experiments to investigate the influence of moisture amount and convection development over the northern South China Sea on a heavy rainfall event in coastal South China on May 8, 2014. Intensive sounding and wind profiles data reveal that there existed a convergence region formed by the southwesterly and easterly jet in the Pearl River delta, which provided favorable conditions for the development of convection. Whether the initial relative humidity field was increased or decreased in the offshore area, or turning off sensible and latent heat release from the cumulus and microphysical processes, had significant effects on the intensity and movement of convection in the coastal areas of Guangdong owing to the adjustment of temperature and wind fields. Especially, when increasing offshore initial humidity, prosperous sea convection modified the circulation in the entire simulation area, and suppressed the development of convection over land. Moreover, if sensible and latent heat from cumulus and microphysical processes was turned off, the low-level jets could reach further north, and the convective system moved to the northeast in the later stage. These experiments indicate that offshore initial moisture filed and convection activity are indeed important for precipitation forecast in the coastal areas, therefore it's necessary to enhance offshore observation and data assimilation methods in the future.

Multi-Layer Arctic Mixed-Phase Clouds Simulated by a Cloud-Resolving Model: Comparison with ARM Observations and Sensitivity Experiments

NASA Technical Reports Server (NTRS)

Luo, Yali; Xu, Kuan-Man; Morrison, Hugh; McFarquhar, Greg M.; Wang, Zhien; Zhang, Gong

2007-01-01

A cloud-resolving model (CRM) is used to simulate the multiple-layer mixed-phase stratiform (MPS) clouds that occurred during a three-and-a-half day subperiod of the Department of Energy-Atmospheric Radiation Measurement Program s Mixed-Phase Arctic Cloud Experiment (M-PACE). The CRM is implemented with an advanced two-moment microphysics scheme, a state-of-the-art radiative transfer scheme, and a complicated third-order turbulence closure. Concurrent meteorological, aerosol, and ice nucleus measurements are used to initialize the CRM. The CRM is prescribed by time-varying large-scale advective tendencies of temperature and moisture and surface turbulent fluxes of sensible and latent heat. The CRM reproduces the occurrences of the single- and double-layer MPS clouds as revealed by the M-PACE observations. However, the simulated first cloud layer is lower and the second cloud layer thicker compared to observations. The magnitude of the simulated liquid water path agrees with that observed, but its temporal variation is more pronounced than that observed. As in an earlier study of single-layer cloud, the CRM also captures the major characteristics in the vertical distributions and temporal variations of liquid water content (LWC), total ice water content (IWC), droplet number concentration and ice crystal number concentration (nis) as suggested by the aircraft observations. However, the simulated mean values differ significantly from the observed. The magnitude of nis is especially underestimated by one order of magnitude. Sensitivity experiments suggest that the lower cloud layer is closely related to the surface fluxes of sensible and latent heat; the upper cloud layer is probably initialized by the large-scale advective cooling/moistening and maintained through the strong longwave (LW) radiative cooling near the cloud top which enhances the dynamical circulation; artificially turning off all ice-phase microphysical processes results in an increase in LWP by a factor of 3 due to interactions between the excessive LW radiative cooling and extra cloud water; heating caused by phase change of hydrometeors could affect the LWC and cloud top height by partially canceling out the LW radiative cooling. It is further shown that the resolved dynamical circulation appears to contribute more greatly to the evolution of the MPS cloud layers than the parameterized subgrid-scale circulation.

Hyper-G stress-induced hyperglycemia in rats mediated by glucoregulatory hormones

NASA Technical Reports Server (NTRS)

Daligcon, B. C.; Oyama, J.

1985-01-01

The present investigation is concerned with possible relations of the hyperglycemic response of rats exposed to hyper-G stress to (1) alterations in blood levels of the glucoregulatory hormones and gluconeogenic substrates, and (2) changes in insulin response on muscle glucose uptake. Male Sprague-Dawley rats weighing 250-300 g were used in the study. The results of the experiments indicate that the initial rapid rise in blood glucose of rats exposed to hyper-G stress is mediated by increases in circulating catecholamines and glucagon, both potent stimulators of hepatic gluconeogenesis. Lactate, derived from epinephrine stimulation of muscle glycogenolysis, appears to be a major precursor for the initial rise in blood glucose. The inhibition of the insulin-stimulated glucose uptake by muscle tissues may be a factor in the observed sustained hyperglycemia.

The Madden-Julian Oscillation and its Impact on Northern Hemisphere Weather Predictability during Wintertime

NASA Technical Reports Server (NTRS)

Jones, Charles; Waliser, Duane E.; Lau, K. M.; Stern, W.

2003-01-01

The Madden-Julian Oscillation (MJO) is known as the dominant mode of tropical intraseasonal variability and has an important role in the coupled-atmosphere system. This study used twin numerical model experiments to investigate the influence of the MJO activity on weather predictability in the midlatitudes of the Northern Hemisphere during boreal winter. The National Aeronautics and Space Administration (NASA) Goddard laboratory for the Atmospheres (GLA) general circulation model was first used in a 10-yr simulation with fixed climatological SSTs to generate a validation data set as well as to select initial conditions for active MJO periods and Null cases. Two perturbation numerical experiments were performed for the 75 cases selected [(4 MJO phases + Null phase) _ 15 initial conditions in each]. For each alternative initial condition, the model was integrated for 90 days. Mean anomaly correlations in the midlatitudes of the Northern Hemisphere (2O deg N_60 deg.N) and standardized root-mean-square errors were computed to validate forecasts and control run. The analyses of 500-hPa geopotential height, 200-hPa Streamfunction and 850-hPa zonal wind component systematically show larger predictability during periods of active MJO as opposed to quiescent episodes of the oscillation.

Burns teaching in UK medical schools: Is it enough?

PubMed

Zinchenko, Ruslan; Perry, Fiona M; Dheansa, Baljit S

2016-02-01

Burns are frequently seen and managed in non-specialist settings. The crowding of the UK medical undergraduate curriculum may have resulted in the reduction of teaching on burns. To determine the burns education experience and the level of competence among UK final year medical students in assessing and acutely managing patients with burns. An online questionnaire was circulated among UK final year medical students. There was a total of 348 respondents. The majority of the respondents (70%) have not received any specific teaching on how to manage patients with burns. Nearly two-thirds of the students (66%) have never seen a patient being managed for burns throughout their training. Over 90% of respondents stated that they would not feel confident in initially managing a burn in the emergency department. The majority of the respondents (57%) have not heard of the criteria for referring a burns patient for further specialist management. There was almost universal agreement about the importance of knowing how to manage a burn initially. There seems to be a lack of consistent undergraduate training in burns management and final year students lack the experience and knowledge to initially manage burns. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

The Pattern and Dynamics of the Meridional Overturning Circulation in the Upper Ocean

DTIC Science & Technology

2008-09-01

Atlantic . Figure 4a shows that the center of meridional overturning circulation occurs at a level of about one kilometer. Circulation is weak at...maintenance of the meridional overturning circulation in the Atlantic Ocean. 5. Global Simulation The most exciting experiment would be to fully model the...mechanisms responsible for the strength and maintenance of the meridional overturning circulation in the Atlantic Ocean are not

Re-assessment of feedbacks from biosphere to Indian Monsoon: RegCMv4.4.5.10 simulations

NASA Astrophysics Data System (ADS)

Lodh, A.

2016-12-01

Biosphere feedback plays an important role in the progression of moisture laden Indian summer monsoon winds over the land regions of India, towards the north-western regions of India, during the Indian summer monsoon regime. Hence, for understanding the biosphere-feedback to Indian monsoon numerical experiments for "control" and "design" cases are performed using ICTP RegCMv4.4.5.10 climate model forced with National Center for Atmospheric Research - II reanalysed fields. The RegCMv4.4.5.10 simulations are performed from 00GMT 1st November 1999 to 24 GMT 1st January 2011, with combination of mixed convective parameterization (viz. Emanuel and Grell) schemes over land and ocean, combined with "University of Washington- Planetary boundary layer" (UW-PBL) and Holtslag PBL scheme. Validation studies are then performed for correct representation of Indian summer monsoon features particularly precipitation and soil moisture. Then, four numerical experiments with LULCC change in the climate model are carried out (for the same initial, boundary forcings and time-period as in control experiment) for determining possible influence of vegetation cover (viz. extended desertification, deforestation and increase in afforestation, irrigated land) on Indian monsoon meteorology. Results from the extended desert and deforestation experiment, informs us that the moisture laden easterlies from Bay of Bengal are not able to move towards the land region owing to formation of anomalous anti-cyclone circulations, resulting in decrease in precipitation over India. From irrigation and afforestation experiment, it is found that there is increase in precipitation, precipitable water, recycling ratio, precipitation efficiency and development of anomalous cyclonic circulations over Central and North-west India. More details about the results from the numerical experiments performed will be explained.

A Numerical Study of Nonlinear Nonhydrostatic Conditional Symmetric Instability in a Convectively Unstable Atmosphere.

NASA Astrophysics Data System (ADS)

Seman, Charles J.

1994-06-01

Nonlinear nonhydrostatic conditional symmetric instability (CSI) is studied as an initial value problem using a two-dimensional (y, z)nonlinear, nonhydrostatic numerical mesoscale/cloud model. The initial atmosphere for the rotating, baroclinic (BCF) simulation contains large convective available potential energy (CAPE). Analytical theory, various model output diagnostics, and a companion nonrotating barotropic (BTNF) simulation are used to interpret the results from the BCF simulation. A single warm moist thermal initiates convection for the two 8-h simulations.The BCF simulation exhibited a very intricate life cycle. Following the initial convection, a series of discrete convective cells developed within a growing mesoscale circulation. Between hours 4 and 8, the circulation grew upscale into a structure resembling that of a squall-line mesoscale convective system (MCS). The mesoscale updrafts were nearly vertical and the circulation was strongest on the baroclinically cool side of the initial convection, as predicted by a two-dimensional Lagrangian parcel model of CSI with CAPE. The cool-side mesoscale circulation grew nearly exponentially over the last 5 h as it slowly propagated toward the warm air. Significant vertical transport of zonal momentum occurred in the (multicellular) convection that developed, resulting in local subgeostrophic zonal wind anomalies aloft. Over time, geostrophic adjustment acted to balance these anomalies. The system became warm core, with mesohigh pressure aloft and mesolow pressure at the surface. A positive zonal wind anomaly also formed downstream from the mesohigh.Analysis of the BCF simulation showed that convective momentum transport played a key role in the evolution of the simulated MCS, in that it fostered the development of the nonlinear CSI on mesoscale time scales. The vertical momentum transport in the initial deep convection generated a subgeostrophic zonal momentum anomaly aloft; the resulting imbalance in pressure gradient and Coriolis forces accelerated the meridional outflow toward the baroclinically cool side, transporting zonal momentum horizontally. The vertical (horizontal) momentum transport occurred on a convective (inertial) time scale. Taken together, the sloping convective updraft/cool side outflow represents the release of the CSI in the convectively unstable atmosphere. Further diagnostics showed that mass transports in the horizontal outflow branch ventilated the upper levels of the system, with enhanced mesoscale lifting in the core and on the leading edge of the MCS, which assisted in convective redevelopments on mesoscale time scales. Geostrophic adjustment acted to balance the convectively generated zonal momentum anomalies, thereby limiting the strength of the meridional outflow predicted by CSI theory. Circulation tendency diagnostics showed that the mesoscale circulation developed in response to thermal wind imbalances generated by the deep convection.Comparison of the BCF and BTNF simulations showed that baroclinicity enhanced mesoscale circulation growth. The BTNF circulation was more transient on mesoscale time and space scales. Overall, the BCF system produced more rainfall than the BTNF.Based on the present and past work in CSI theory, a new definition for the term `slantwise convection' is proposed.

Drift dynamics in a coupled model initialized for decadal forecasts

NASA Astrophysics Data System (ADS)

Sanchez-Gomez, Emilia; Cassou, Christophe; Ruprich-Robert, Yohan; Fernandez, Elodie; Terray, Laurent

2016-03-01

Drifts are always present in models when initialized from observed conditions because of intrinsic model errors; those potentially affect any type of climate predictions based on numerical experiments. Model drifts are usually removed through more or less sophisticated techniques for skill assessment, but they are rarely analysed. In this study, we provide a detailed physical and dynamical description of the drifts in the CNRM-CM5 coupled model using a set of decadal retrospective forecasts produced within CMIP5. The scope of the paper is to give some physical insights and lines of approach to, on one hand, implement more appropriate techniques of initialisation that minimize the drift in forecast mode, and on the other hand, eventually reduce the systematic biases of the models. We first document a novel protocol for ocean initialization adopted by the CNRM-CERFACS group for forecasting purpose in CMIP5. Initial states for starting dates of the predictions are obtained from a preliminary integration of the coupled model where full-field ocean surface temperature and salinity are restored everywhere to observations through flux derivative terms and full-field subsurface fields (below the prognostic ocean mixed layer) are nudged towards NEMOVAR reanalyses. Nudging is applied only outside the 15°S-15°N band allowing for dynamical balance between the depth and tilt of the tropical thermocline and the model intrinsic biased wind. A sensitivity experiment to the latitudinal extension of no-nudging zone (1°S-1°N instead of 15°, hereafter referred to as NOEQ) has been carried out. In this paper, we concentrate our analyses on two specific regions: the tropical Pacific and the North Atlantic basins. In the Pacific, we show that the first year of the forecasts is characterized by a quasi-systematic excitation of El Niño-Southern Oscillation (ENSO) warm events whatever the starting dates. This, through ocean-to-atmosphere heat transfer materialized by diabatic heating, can be viewed for the coupled model as an efficient way to rapidly adjust to its own biased climate mean state. Weak cold ENSO events tend to occur the second year of the forecast due to the so-called discharge-recharge mechanism while the spurious oscillatory behavior is progressively damped. The latter mechanism is much more pronounced in retrospective forecasts initialized from the NOEQ configuration for which the ENSO flip-flop is still detectable at leadtime 4 year. Associated atmospheric teleconnections interfere worldwide with regional drifts, especially in the North Pacific and more remotely in the North Atlantic. In the latter basin, the drift can be interpreted as the model response to intrinsic atmospheric circulation biases found in the stand-alone atmosphere component of the model, which project onto the negative phase of the North Atlantic Oscillation. A fast adjustment (up to ~5-year leadtime) occurs leading to a rapid slackening of both the vertical (Atlantic meridional overturning circulation) and horizontal circulations, especially in the subpolar gyre. Slower adjustment of the entire water masses distribution in the North Atlantic then takes over involving several mechanisms. We show that a weak feedback is locally present between the atmospheric circulation and the ocean drift that controls the timescale of the setting of the coupled model biases.

Degradation of trichloroethylene by photocatalysis in an internally circulating slurry bubble column reactor.

PubMed

Jeon, Jin Hee; Kim, Sang Done; Lim, Tak Hyoung; Lee, Dong Hyun

2005-08-01

The effects of initial trichloroethylene (TCE) concentration, recirculating liquid flow rate and gas velocity on photodegradation of TCE have been determined in an internally circulating slurry bubble column reactor (0.15m-ID x 0.85 m-high). Titanium dioxide (TiO2) powder was employed as a photocatalyst and the optimum loading of TiO2 in the present system is found to be approximately 0.2 wt%. The stripping fraction of TCE by air flow increases but photodegradation fraction of TCE decreases with increasing the initial TCE concentration, recirculating liquid flow rate and gas velocity. The average removal efficiency of TCE is found to be approximately 97% in an internally circulating slurry bubble column reactor.

Laboratory Study of Magnetorotational Instability and Hydrodynamic Stability at Large Reynolds Numbers

NASA Technical Reports Server (NTRS)

Ji, H.; Burin, M.; Schartman, E.; Goodman, J.; Liu, W.

2006-01-01

Two plausible mechanisms have been proposed to explain rapid angular momentum transport during accretion processes in astrophysical disks: nonlinear hydrodynamic instabilities and magnetorotational instability (MRI). A laboratory experiment in a short Taylor-Couette flow geometry has been constructed in Princeton to study both mechanisms, with novel features for better controls of the boundary-driven secondary flows (Ekman circulation). Initial results on hydrodynamic stability have shown negligible angular momentum transport in Keplerian-like flows with Reynolds numbers approaching one million, casting strong doubt on the viability of nonlinear hydrodynamic instability as a source for accretion disk turbulence.

Determination of the extra buffering distance in the one-way nesting procedure for the regional ocean

NASA Astrophysics Data System (ADS)

Hwang, Jin Hwan; Pham, Van Sy

2017-04-01

The Big-Brother Experiment (BBE) evaluates the effect of domain size on the ocean regional circulation model (ORCMs) in the downscaling and nesting from the ocean global circulation (OGCMs). The BBE first establishes a mimic ocean global circulation models (M-OGCMs) data and employs a ORCM to simulate for a highly resolved large domain. This M-OGCM's results were then filtered to remove short scales then used for boundary and initial conditions of the nested ORCMs, which have the same resolution to the M-OGCMs. The various sizes of domain were embedded in the M-OGCMs and the cases were simulated to see the effect of domain size with the extra buffering distance to the results of the ORCMs. The diagnostic variables including temperature, salinity and vorticity of the nested domain are then compared with those of the M-OGCMs before filtering. Differences between them can address the errors associating with the sizes of the domain, which are not attributed unambiguously to models errors or observational errors. The results showed that domain size significantly impacts on the results of ORCMs. As the domain size of the ORCM becomes lager, the distance of the extra space between the area of interest and the updated LBCs increases. So, the results of ORCMs perform more highly correlated with the M-OGCM. But, there are a certain optimal sizes of the OGCMs, which could be larger than nested ORCMs' domain size from 2 to 10 times, depending on the computational costs. Key words: domain size, error, ocean regional circulation model, Big-Brother Experiment. Acknowledgement: This research was supported by grants from the Korean Ministry of Oceans and Fisheries entitled "Development of integrated estuarine management system" and a National Research Foundation of Korea (NRF) Grant (No. 2015R1A5A 7037372) funded by MSIP of Korea. The authors thank the Integrated Research Institute of Construction and Environmental Engineering of Seoul National University for administrative support.

The Numerical Studies Program for the Atmospheric General Circulation Experiment (AGCE) for Spacelab Flights

NASA Technical Reports Server (NTRS)

Fowlis, W. W. (Editor); Davis, M. H. (Editor)

1981-01-01

The atmospheric general circulation experiment (AGCE) numerical design for Spacelab flights was studied. A spherical baroclinic flow experiment which models the large scale circulations of the Earth's atmosphere was proposed. Gravity is simulated by a radial dielectric body force. The major objective of the AGCE is to study nonlinear baroclinic wave flows in spherical geometry. Numerical models must be developed which accurately predict the basic axisymmetric states and the stability of nonlinear baroclinic wave flows. A three dimensional, fully nonlinear, numerical model and the AGCE based on the complete set of equations is required. Progress in the AGCE numerical design studies program is reported.

How sex work becomes an option: Experiences of female sex workers in Kerman, Iran.

PubMed

Karamouzian, Mohammad; Foroozanfar, Zohre; Ahmadi, Azal; Haghdoost, Ali Akbar; Vogel, Joanna; Zolala, Farzaneh

2016-01-01

Sex work is rarely an occupation of choice for Iranian women and is often described as a last resort. While several factors play a role in creating an environment where individuals become involved in sex work, female sex workers' experiences regarding entry into sex work in Iran are poorly understood. In this qualitative study, a convenience sample of 24 participants was recruited from a drop-in centre for vulnerable women in Kerman, Iran. Through in-depth interviews, participants were asked about their personal lived experiences of initiating sex work. Grounded theory was used to analyse findings from this research. We learned that major factors impacting on women's initiation into sex work circulated around their vulnerability and chronic poverty. Participants continued to sell sex due to their limited opportunities, drug dependence and financial needs. Improving sex workers' economic status could be a vital intervention in providing vulnerable women with options other than sex work. Female sex workers should be provided with government support and educational programmes delivered through special centres. Despite the illegal status of their work, sex workers' needs should be recognised across all aspects of policy and legislation.

Time-resolved particle image velocimetry measurements of the 3D single-mode Richtmyer-Meshkov instability

NASA Astrophysics Data System (ADS)

Xu, Qian; Krivets, Vitaliy V.; Sewell, Everest G.; Jacobs, Jeffrey W.

2016-11-01

A vertical shock tube is used to perform experiments on the single-mode three-dimensional Richtmyer-Meshkov Instability (RMI). The light gas (Air) and the heavy gas (SF6) enter from the top and the bottom of the shock tube driven section to form the interface. The initial perturbation is then generated by oscillating the gases vertically. Both gases are seeded with particles generated through vaporizing propylene glycol. An incident shock wave (M 1.2) impacts the interface to create an impulsive acceleration. The seeded particles are illuminated by a dual cavity 75W, Nd: YLF laser. Three high-speed CMOS cameras record time sequences of image pairs at a rate of 2 kHz. The initial perturbation used is that of a single, square-mode perturbation with either a single spike or a single bubble positioned at the center of the shock tube. The full time dependent velocity field is obtained allowing the determination of the circulation versus time. In addition, the evolution of time dependent amplitude is also determined. The results are compared with PIV measurements from previous two-dimensional single mode experiments along with PLIF measurements from previous three-dimensional single mode experiments.

Fault geometry and mechanics of marly carbonate multilayers: An integrated field and laboratory study from the Northern Apennines, Italy

NASA Astrophysics Data System (ADS)

Giorgetti, C.; Collettini, C.; Scuderi, M. M.; Barchi, M. R.; Tesei, T.

2016-12-01

Sealing layers are often represented by sedimentary sequences characterized by alternating strong and weak lithologies. When involved in faulting processes, these mechanically heterogeneous multilayers develop complex fault geometries. Here we investigate fault initiation and evolution within a mechanical multilayer by integrating field observations and rock deformation experiments. Faults initiate with a staircase trajectory that partially reflects the mechanical properties of the involved lithologies, as suggested by our deformation experiments. However, some faults initiating at low angles in calcite-rich layers (θi = 5°-20°) and at high angles in clay-rich layers (θi = 45°-86°) indicate the important role of structural inheritance at the onset of faulting. With increasing displacement, faults develop well-organized fault cores characterized by a marly, foliated matrix embedding fragments of limestone. The angles of fault reactivation, which concentrate between 30° and 60°, are consistent with the low friction coefficient measured during our experiments on marls (μs = 0.39), indicating that clay minerals exert a main control on fault mechanics. Moreover, our integrated analysis suggests that fracturing and faulting are the main mechanisms allowing fluid circulation within the low-permeability multilayer, and that its sealing integrity can be compromised only by the activity of larger faults cutting across its entire thickness.

Evidence for circulating cancer stem-like cells and epithelial-mesenchymal transition phenotype in the pleurospheres derived from lung adenocarcinoma using liquid biopsy.

PubMed

Mirza, Sheefa; Jain, Nayan; Rawal, Rakesh

2017-03-01

Lung cancer stem cells are supposed to be the main drivers of tumor initiation, maintenance, drug resistance, and relapse of the disease. Hence, identification of the cellular and molecular aspects of these cells is a prerequisite for targeted therapy of lung cancer. Currently, analysis of circulating tumor cells has the potential to become the main diagnostic technique to monitor disease progression or therapeutic response as it is non-invasive. However, accurate detection of circulating tumor cells has remained a challenge, as epithelial cell markers used so far are not always trustworthy for detecting circulating tumor cells, especially during epithelial-mesenchymal transition. As cancer stem cells are the only culprit to initiate metastatic tumors, our aim was to isolate and characterize circulating tumor stem cells rather than circulating tumor cells from the peripheral blood of NSCLC adenocarcinoma as limited data are available addressing the gene expression profiling of lung cancer stem cells. Here, we reveal that CD44(+)/CD24(-) population in circulation not only exhibit stem cell-related genes but also possess epithelial-mesenchymal transition characteristics. In conclusion, the use of one or more cancer stem cell markers along with epithelial, mesenchymal and epithelial mesenchymal transition markers will prospectively provide the most precise assessment of the threat for recurrence and metastatic disease and has a great potential for forthcoming applications in harvesting circulating tumor stem cells and their downstream applications. Our results will aid in developing diagnostic and prognostic modalities and personalized treatment regimens like dendritic cell-based immunotherapy that can be utilized for targeting and eliminating circulating tumor stem cells, to significantly reduce the possibility of relapse and improve clinical outcomes.

Verification of RELAP5-3D code in natural circulation loop as function of the initial water inventory

NASA Astrophysics Data System (ADS)

Bertani, C.; Falcone, N.; Bersano, A.; Caramello, M.; Matsushita, T.; De Salve, M.; Panella, B.

2017-11-01

High safety and reliability of advanced nuclear reactors, Generation IV and Small Modular Reactors (SMR), have a crucial role in the acceptance of these new plants design. Among all the possible safety systems, particular efforts are dedicated to the study of passive systems because they rely on simple physical principles like natural circulation, without the need of external energy source to operate. Taking inspiration from the second Decay Heat Removal system (DHR2) of ALFRED, the European Generation IV demonstrator of the fast lead cooled reactor, an experimental facility has been built at the Energy Department of Politecnico di Torino (PROPHET facility) to study single and two-phase flow natural circulation. The facility behavior is simulated using the thermal-hydraulic system code RELAP5-3D, which is widely used in nuclear applications. In this paper, the effect of the initial water inventory on natural circulation is analyzed. The experimental time behaviors of temperatures and pressures are analyzed. The experimental matrix ranges between 69 % and 93%; the influence of the opposite effects related to the increase of the volume available for the expansion and the pressure raise due to phase change is discussed. Simulations of the experimental tests are carried out by using a 1D model at constant heat power and fixed liquid and air mass; the code predictions are compared with experimental results. Two typical responses are observed: subcooled or two phase saturated circulation. The steady state pressure is a strong function of liquid and air mass inventory. The numerical results show that, at low initial liquid mass inventory, the natural circulation is not stable but pulsated.

Decadal Prediction Skill in the GEOS-5 Forecast System

NASA Technical Reports Server (NTRS)

Ham, Yoo-Geun; Rienecker, Michael M.; Suarez, M.; Vikhliaev, Yury V.; Zhao, Bin; Marshak, Jelena; Vernieres, Guillaume; Schubert, Siegfried D.

2012-01-01

A suite of decadal predictions has been conducted with the NASA Global Modeling and Assimilation Office?s GEOS-5 Atmosphere-Ocean General Circulation Model (AOGCM). The hindcasts are initialized every December from 1959 to 2010 following the CMIP5 experimental protocol for decadal predictions. The initial conditions are from a multi-variate ensemble optimal interpolation ocean and sea-ice reanalysis, and from the atmospheric reanalysis (MERRA, the Modern-Era Retrospective Analysis for Research and Applications) generated using the GEOS-5 atmospheric model. The forecast skill of a three-member-ensemble mean is compared to that of an experiment without initialization but forced with observed CO2. The results show that initialization acts to increase the forecast skill of Northern Atlantic SST compared to the uninitialized runs, with the increase in skill maintained for almost a decade over the subtropical and mid-latitude Atlantic. The annual-mean Atlantic Meridional Overturning Circulation (AMOC) index is predictable up to a 5-year lead time, consistent with the predictable signal in upper ocean heat content over the Northern Atlantic. While the skill measured by Mean Squared Skill Score (MSSS) shows 50% improvement up to 10-year lead forecast over the subtropical and mid-latitude Atlantic, however, prediction skill is relatively low in the subpolar gyre, due in part to the fact that the spatial pattern of the dominant simulated decadal mode in upper ocean heat content over this region appears to be unrealistic. An analysis of the large-scale temperature budget shows that this is the result of a model bias, implying that realistic simulation of the climatological fields is crucial for skillful decadal forecasts.

Dissolution-induced preferential flow in a limestone fracture.

PubMed

Liu, Jishan; Polak, Amir; Elsworth, Derek; Grader, Avrami

2005-06-01

Flow in a rock fracture is surprisingly sensitive to the evolution of flow paths that develop as a result of dissolution. Net dissolution may either increase or decrease permeability uniformly within the fracture, or may form a preferential flow path through which most of the injected fluid flows, depending on the prevailing ambient mechanical and chemical conditions. A flow-through test was completed on an artificial fracture in limestone at room temperature under ambient confining stress of 3.5 MPa. The sample was sequentially circulated by water of two different compositions through the 1500 h duration of the experiment; the first 935 h by tap groundwater, followed by 555 h of distilled water. Measurements of differential pressures between the inlet and the outlet, fluid and dissolved mass fluxes, and concurrent X-ray CT imaging and sectioning were used to characterize the evolution of flow paths within the limestone fracture. During the initial circulation of groundwater, the differential pressure increased almost threefold, and was interpreted as a net reduction in permeability as the contacting asperities across the fracture are removed, and the fracture closes. With the circulation of distilled water, permeability initially reduces threefold, and ultimately increases by two orders of magnitude. This spontaneous switch from net decrease in permeability, to net increase occurred with no change in flow rate or applied effective stress, and is attributed to the evolving localization of flow path as evidenced by CT images. Based on the X-ray CT characterizations, a flow path-dependent flow model was developed to simulate the evolution of flow paths within the fracture and its influence on the overall flow behaviors of the injected fluid in the fracture.

Cyclonic circulation of Saturn's atmosphere due to tilted convection

NASA Astrophysics Data System (ADS)

Afanasyev, Y. D.; Zhang, Y.

2018-03-01

Saturn displays cyclonic vortices at its poles and the general atmospheric circulation at other latitudes is dominated by embedded zonal jets that display cyclonic circulation. The abundance of small-scale convective storms suggests that convection plays a role in producing and maintaining Saturn's atmospheric circulation. However, the dynamical influence of small-scale convection on Saturn's general circulation is not well understood. Here we present laboratory analogue experiments and propose that Saturn's cyclonic circulation can be explained by tilted convection in which buoyancy forces do not align with the planet's rotation axis. In our experiments—conducted with a cylindrical water tank that is heated at the bottom, cooled at the top and spun on a rotating table—warm rising plumes and cold sinking water generate small anticyclonic and cyclonic vortices that are qualitatively similar to Saturn's convective storms. Numerical simulations complement the experiments and show that this small-scale convection leads to large-scale cyclonic flow at the surface and anticyclonic circulation at the base of the fluid layer, with a polar vortex forming from the merging of smaller cyclonic storms that are driven polewards.

A MODEL FOR FINE PARTICLE AGGLOMERATION IN CIRCULATING FLUIDIZED BED ABSORBERS

EPA Science Inventory

A model for fine particle agglomeration in circulating fluidized bed absorbers (CFBAS) has been developed. It can model the influence of different factors on agglomeration, such as the geometry of CFBAs, superficial gas velocity, initial particle size distribution, and type of ag...

Themes on circulation in the third world.

PubMed

Chapman, M; Prothero, R M

1983-01-01

"This article focuses upon circulation, or reciprocal flows of people, with specific reference to Third World societies." Aspects considered include attempts to standardize terminology and to formulate typologies of population movement; the development of explanatory models of circulation and modernization, social networks, family welfare, and capitalism; and "the transfer of methods and concepts to societies and populations different from those from which they initially evolved and in which they were first tested." excerpt

Development of an AMS method to study oceanic circulation characteristics using cosmogenic 39Ar

USGS Publications Warehouse

Collon, P.H.; Bichler, M.; Caggiano, J.; Cecil, L.D.; El, Masri Y.; Golser, R.; Jiang, C.L.; Heinz, A.; Henderson, D.; Kutschera, W.; Lehmann, B.E.; Leleux, P.; Loosli, H.H.; Pardo, R.C.; Paul, M.; Rehm, K.E.; Schlosser, P.; Scott, R.H.; Smethie, W.M.; Vondrasek, R.

2004-01-01

Initial experiments at the ATLAS facility [Nucl. Instr. and Meth. B 92 (1994) 241] resulted in a clear detection of cosmogenic 39Ar signal at the natural level. The present paper summarizes the recent developments of 39Ar AMS measurements at ATLAS: the use of an electron cyclotron resonance (ECR) positive ion source equipped with a special quartz liner to reduce 39K background, the development of a gas handling system for small volume argon samples, the acceleration of 39Ar8+ ions to 232 MeV, and the final separation of 39Ar from 39K in a gas-filled spectrograph. The first successful AMS measurements of 39Ar in ocean water samples from the Southern Atlantic ventilation experiment (SAVE) are reported. Published by Elsevier B.V.

(abstract) Cometary Particles as a Tracer of Jupiter's Stratospheric Circulation

NASA Technical Reports Server (NTRS)

West, R. A.; Friedson, A. J.

1993-01-01

The impact of fragments of comet Shoemaker-Levy 9 on Jupiter's atmosphere in July 1994 may provide an unprecedented opportunity to study Jupiter's stratospheric circulation. Recent calculations by Z. Sekanina predict that much of the comet material will be deposited in Jupiter's stratosphere. If so, and if the material is deposited in a confined region (10 000 km or less, horizontally) we can expect a situation analogous to an El Chichon or Pinatubo event for the terrestrial stratosphere. Initially the volatile material will be vaporized and will rapidly recondense. The large ice crystals and dust particles will rain out and be lost to the troposphere. The cloud of small particles which remain may have settling times of more than a year. These submicron to micron particles would probably be easily seen in methane filter images in the near-IR, and possibly in the ultraviolet. An observational program to monitor the dispersal of this cloud or clouds would reveal much about the nature of the circulation. Some predictions about the meridional evolution of the clouds can be made already, based on the meridional circulation model of West et al. unless the impact itself significantly disrupts the annual average circulation well after the initial transients die away.

Rice production with minimal irrigation and no nitrogen fertilizer by intensive use of treated municipal wastewater.

PubMed

Muramatsu, Ayumi; Watanabe, Toru; Sasaki, Atsushi; Ito, Hiroaki; Kajihara, Akihiko

2014-01-01

We designed a new cultivation system of rice with circulated irrigation to remove nitrogen from treated municipal wastewater effectively and assessed the possibility of nitrogen removal in the new system without any adverse effects on rice production through bench-scale experiments through two seasons. Overgrowth of the rice plant, which can lead to lodging and tasteless rice, was found in the first season probably because nitrogen supply based on standard practice in normal paddy fields was too much in the closed irrigation system. In the second season, therefore, the amount of treated wastewater initially applied to the system was reduced but this resulted in a considerably decreased yield. On the other hand, the taste of the rice was significantly improved. The two-season experiments revealed that the new system enabled rice production with minimal irrigation (approximately 50% on the yield base compared to normal paddy fields) and no nitrogen fertilizer. The system also achieved >95% removal of nitrogen from the treated wastewater used for circulated irrigation. The accumulation of harmful metals in the rice was not observed after one season of cultivation in the new system. The accumulation after cultivation using the same soil repeatedly for a longer time should be examined by further studies.

Recent changes in the summer monsoon circulation and their impact on dynamics and thermodynamics of the Arabian Sea

NASA Astrophysics Data System (ADS)

Pratik, Kad; Parekh, Anant; Karmakar, Ananya; Chowdary, Jasti S.; Gnanaseelan, C.

2018-05-01

The present study examines changes in the low-level summer monsoon circulation over the Arabian Sea and their impact on the ocean dynamics using reanalysis data. The study confirms intensification and northward migration of low-level jet during 1979 to 2015. Further during the study period, an increase in the Arabian Sea upper ocean heat content is found in spite of a decreasing trend in the net surface heat flux, indicating the possible role of ocean dynamics in the upper ocean warming. Increase in the anti-cyclonic wind stress curl associated with the change in the monsoon circulation induces downwelling over the central Arabian Sea, favoring upper ocean warming. The decreasing trend of southward Ekman transport, a mechanism transporting heat from the land-locked north Indian Ocean to southern latitudes, also supports increasing trend of the upper ocean heat content. To reinstate and quantify the role of changing monsoon circulation in increasing the heat content over the Arabian Sea, sensitivity experiment is carried out using ocean general circulation model. In this experiment, the model is forced by inter-annual momentum forcing while rest of the forcing is climatological. Experiment reveals that the changing monsoon circulation increases the upper ocean heat content, effectively by enhancing downwelling processes and reducing southward heat transport, which strongly endorses our hypothesis that changing ocean dynamics associated with low-level monsoon circulation is causing the increasing trend in the heat content of the Arabian Sea.

Decadal Prediction Efforts in GMAO (Global Modeling and Assimilation Office)

NASA Technical Reports Server (NTRS)

Rienecker, Michele M.; Suarez, Max; Schubert, Siegfried

2010-01-01

The Global Modeling and Assimilation Office (GMAO) plans to use our GEOS-5 atmosphere-ocean general circulation model (AOGCM) to explore issues associated with predictability on decadal time scales and to contribute to the decadal prediction project that is part ofCMIP5. The GEOS-5 AOGCM is comprised of the GEOS-5 AGCM with the Catchment Land Surface Model, coupled to GFDL's MOM, version 4. We have assimilation systems for both the atmosphere and ocean. For our climate prediction efforts, the atmosphere will be initialized from the GEOS-5 Modem Era Retrospective-analysis for Research and Applications (MERRA), available from 1979 to present at 112 resolution, and from 1948 to present at 2 resolution. The ocean assimilation is conducted within the coupled model framework, using the MERRA as a constraint for both the atmosphere and the ocean. The decadal prediction experiments will be conducted with a 1 atmosphere and a 112 ocean. Some initial results will be presented, focusing on initialization aspects of the GEOS-5 system.

Decadal Prediction Skill in the GEOS-5 Forecast System

NASA Technical Reports Server (NTRS)

Ham, Yoo-Geun; Rienecker, Michele M.; Suarez, Max J.; Vikhliaev, Yury; Zhao, Bin; Marshak, Jelena; Vernieres, Guillaume; Schubert, Siegfried D.

2013-01-01

A suite of decadal predictions has been conducted with the NASA Global Modeling and Assimilation Office's (GMAO's) GEOS-5 Atmosphere-Ocean general circulation model. The hind casts are initialized every December 1st from 1959 to 2010, following the CMIP5 experimental protocol for decadal predictions. The initial conditions are from a multivariate ensemble optimal interpolation ocean and sea-ice reanalysis, and from GMAO's atmospheric reanalysis, the modern-era retrospective analysis for research and applications. The mean forecast skill of a three-member-ensemble is compared to that of an experiment without initialization but also forced with observed greenhouse gases. The results show that initialization increases the forecast skill of North Atlantic sea surface temperature compared to the uninitialized runs, with the increase in skill maintained for almost a decade over the subtropical and mid-latitude Atlantic. On the other hand, the initialization reduces the skill in predicting the warming trend over some regions outside the Atlantic. The annual-mean Atlantic meridional overturning circulation index, which is defined here as the maximum of the zonally-integrated overturning stream function at mid-latitude, is predictable up to a 4-year lead time, consistent with the predictable signal in upper ocean heat content over the North Atlantic. While the 6- to 9-year forecast skill measured by mean squared skill score shows 50 percent improvement in the upper ocean heat content over the subtropical and mid-latitude Atlantic, prediction skill is relatively low in the sub-polar gyre. This low skill is due in part to features in the spatial pattern of the dominant simulated decadal mode in upper ocean heat content over this region that differ from observations. An analysis of the large-scale temperature budget shows that this is the result of a model bias, implying that realistic simulation of the climatological fields is crucial for skillful decadal forecasts.

Noninvasive and label-free detection of circulating melanoma cells by in vivo photoacoustic flow cytometry

NASA Astrophysics Data System (ADS)

Yang, Ping; Liu, Rongrong; Niu, Zhenyu; Suo, Yuanzhen; He, Hao; Wei, Xunbin

2015-03-01

Melanoma is a malignant tumor of melanocytes. Circulating melanoma cell has high light absorption due to melanin highly contained in melanoma cells. This property is employed for the detection of circulating melanoma cell by in vivo photoacoustic flow cytometry (PAFC). PAFC is based on photoacoustic effect. Compared to in vivo flow cytometry based on fluorescence, PAFC can employ high melanin content of melanoma cells as endogenous biomarkers to detect circulating melanoma cells in vivo. In our research, we developed in vitro experiments to prove the ability of PAFC system of detecting PA signals from melanoma cells. For in vivo experiments, we constructed a model of melanoma tumor bearing mice by inoculating highly metastatic murine melanoma cancer cells B16F10 with subcutaneous injection. PA signals were detected in the blood vessels of mouse ears in vivo. By counting circulating melanoma cells termly, we obtained the number variation of circulating melanoma cells as melanoma metastasized. Those results show that PAFC is a noninvasive and label-free method to detect melanoma metastases in blood or lymph circulation. Our PAFC system is an efficient tool to monitor melanoma metastases, cancer recurrence and therapeutic efficacy.

Analysis of a Non-Developing Tropical Circulation System During the Tropical Cyclone Structure (TCS08) Field Experiment

DTIC Science & Technology

2009-12-01

Research and Predictability Experiment (THORPEX) Pacific Asian Regional Campaigns (T- PARC ). Aircraft dropwindsondes, special ELDORA radar observations...systems within TCS025 at 2030 UTC 24 August 2008. D. ELDORA BACKGROUND For the combined TCS08 and T- PARC field experiment, the ELDORA radar was...SUBJECT TERMS Electra Doppler Radar (ELDORA), Tropical Cyclone Structure (TCS08), TCS08, Tropical Cyclone Formation, Tropical Circulation System

Tobacco and e-cigarette products initiate Kupffer cell inflammatory responses.

PubMed

Rubenstein, David A; Hom, Sarah; Ghebrehiwet, Berhane; Yin, Wei

2015-10-01

Kupffer cells are liver resident macrophages that are responsible for screening and clearing blood of pathogens and foreign particles. It has recently been shown that Kupffer cells interact with platelets, through an adhesion based mechanism, to aid in pathogen clearance and then these platelets re-enter the general systemic circulation. Thus, a mechanism has been identified that relates liver inflammation to possible changes in the systemic circulation. However, the role that Kupffer cells play in cardiovascular disease initiation/progression has not been elucidated. Thus, our objective was to determine whether or not Kupffer cells are responsive to a classical cardiovascular risk factor and if these changes can be transmitted into the general systemic circulation. If Kupffer cells initiate inflammatory responses after exposure to classical cardiovascular risk factors, then this provides a potential alternative/synergistic pathway for cardiovascular disease initiation. We aimed to elucidate the prevalence of this potential pathway. We hypothesized that Kupffer cells would initiate a robust inflammatory response after exposure to tobacco cigarette or e-cigarette products and that the inflammatory response would have the potential to antagonize other salient cells for cardiovascular disease progression. To test this, Kupffer cells were incubated with tobacco smoke extracts, e-cigarette vapor extracts or pure nicotine. Complement deposition onto Kupffer cells, Kupffer cell complement receptor expression, oxidative stress production, cytokine release and viability and density were assessed after the exposure. We observed a robust inflammatory response, oxidative stress production and cytokine release after Kupffer cells were exposed to tobacco or e-cigarette extracts. We also observed a marginal decrease in cell viability coupled with a significant decrease in cell density. In general, this was not a function of the extract formulation (e.g. tobacco vs. e-cigarette products or the formulation of the cigarette product). These results indicate that Kupffer cells are responsive to classical cardiovascular risk factors and that an inflammatory response is initiated that may pass into the general systemic circulation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Selecting Meteorological Input for the Global Modeling Initiative Assessments

NASA Technical Reports Server (NTRS)

Strahan, Susan; Douglass, Anne; Prather, Michael; Coy, Larry; Hall, Tim; Rasch, Phil; Sparling, Lynn

1999-01-01

The Global Modeling Initiative (GMI) science team has developed a three dimensional chemistry and transport model (CTM) to evaluate the impact of the exhaust of supersonic aircraft on the stratosphere. An important goal of the GMI is to test modules for numerical transport, photochemical integration, and model dynamics within a common framework. This work is focussed on the dependence of the overall assessment on the wind and temperature fields used by the CTM. Three meteorological data sets for the stratosphere were available to GMI: the National Center for Atmospheric Research Community Climate Model (CCM2), the Goddard Earth Observing System Data Assimilation System (GEOS-DAS), and the Goddard Institute for Space Studies general circulation model (GISS-2'). Objective criteria were established by the GMI team to evaluate which of these three data sets provided the best representation of trace gases in the stratosphere today. Tracer experiments were devised to test various aspects of model transport. Stratospheric measurements of long-lived trace gases were selected as a test of the CTM transport. This presentation describes the criteria used in grading the meteorological fields and the resulting choice of wind fields to be used in the GMI assessment. This type of objective model evaluation will lead to a higher level of confidence in these assessments. We suggest that the diagnostic tests shown here be used to augment traditional general circulation model evaluation methods.

Liquid biopsy in pancreatic cancer: the beginning of a new era

PubMed Central

Yadav, Dipesh Kumar; Bai, Xueli; Yadav, Rajesh Kumar; Singh, Alina; Li, Guogang; Ma, Tao; Chen, Wei; Liang, Tingbo

2018-01-01

With dismal survival rate pancreatic cancer remains one of the most aggressive and devastating malignancy. Predominantly, due to the absence of a dependable methodology for early identification and limited therapeutic options for advanced disease. However, it takes over 17 years to develop pancreatic cancer from initiation of mutation to metastatic cancer; therefore, if diagnosed early; it may increase overall survival dramatically, thus, providing a window of opportunity for early detection. Recently, genomic expression analysis defined 4 subtypes of pancreatic cancer based on mutated genes. Hence, we need simple and standard, minimally invasive test that can monitor those altered genes or their associated pathways in time for the success of precision medicine, and liquid biopsy seems to be one answer to all these questions. Again, liquid biopsy has an ability to pair with genomic tests. Additionally, liquid biopsy based development of circulating tumor cells derived xenografts, 3D organoids system, real-time monitoring of genetic mutations by circulating tumor DNA and exosome as the targeted drug delivery vehicle holds lots of potential for the treatment and cure of pancreatic cancer. At present, diagnosis of pancreatic cancer is frantically done on the premise of CA19-9 and radiological features only, which doesn't give a picture of genetic mutations and epigenetic alteration involved. In this manner, the current diagnostic paradigm for pancreatic cancer diagnosis experiences low diagnostic accuracy. This review article discusses the current state of liquid biopsy in pancreatic cancer as diagnostic and therapeutic tools and future perspectives of research in the light of circulating tumor cells, circulating tumor DNA and exosomes.

An advanced method for classifying atmospheric circulation types based on prototypes connectivity graph

NASA Astrophysics Data System (ADS)

Zagouras, Athanassios; Argiriou, Athanassios A.; Flocas, Helena A.; Economou, George; Fotopoulos, Spiros

2012-11-01

Classification of weather maps at various isobaric levels as a methodological tool is used in several problems related to meteorology, climatology, atmospheric pollution and to other fields for many years. Initially the classification was performed manually. The criteria used by the person performing the classification are features of isobars or isopleths of geopotential height, depending on the type of maps to be classified. Although manual classifications integrate the perceptual experience and other unquantifiable qualities of the meteorology specialists involved, these are typically subjective and time consuming. Furthermore, during the last years different approaches of automated methods for atmospheric circulation classification have been proposed, which present automated and so-called objective classifications. In this paper a new method of atmospheric circulation classification of isobaric maps is presented. The method is based on graph theory. It starts with an intelligent prototype selection using an over-partitioning mode of fuzzy c-means (FCM) algorithm, proceeds to a graph formulation for the entire dataset and produces the clusters based on the contemporary dominant sets clustering method. Graph theory is a novel mathematical approach, allowing a more efficient representation of spatially correlated data, compared to the classical Euclidian space representation approaches, used in conventional classification methods. The method has been applied to the classification of 850 hPa atmospheric circulation over the Eastern Mediterranean. The evaluation of the automated methods is performed by statistical indexes; results indicate that the classification is adequately comparable with other state-of-the-art automated map classification methods, for a variable number of clusters.

Lung cancer perfusion: can we measure pulmonary and bronchial circulation simultaneously?

PubMed

Yuan, Xiaodong; Zhang, Jing; Ao, Guokun; Quan, Changbin; Tian, Yuan; Li, Hong

2012-08-01

To describe a new CT perfusion technique for assessing the dual blood supply in lung cancer and present the initial results. This study was approved by the institutional review board. A CT protocol was developed, and a dual-input CT perfusion (DI-CTP) analysis model was applied and evaluated regarding the blood flow fractions in lung tumours. The pulmonary trunk and the descending aorta were selected as the input arteries for the pulmonary circulation and the bronchial circulation respectively. Pulmonary flow (PF), bronchial flow (BF), and a perfusion index (PI, = PF/ (PF + BF)) were calculated using the maximum slope method. After written informed consent was obtained, 13 consecutive subjects with primary lung cancer underwent DI-CTP. Perfusion results are as follows: PF, 13.45 ± 10.97 ml/min/100 ml; BF, 48.67 ± 28.87 ml/min/100 ml; PI, 21 % ± 11 %. BF is significantly larger than PF, P < 0.001. There is a negative correlation between the tumour volume and perfusion index (r = 0.671, P = 0.012). The dual-input CT perfusion analysis method can be applied successfully to lung tumours. Initial results demonstrate a dual blood supply in primary lung cancer, in which the systemic circulation is dominant, and that the proportion of the two circulation systems is moderately dependent on tumour size. A new CT perfusion technique can assess lung cancer's dual blood supply. A dual blood supply was confirmed with dominant bronchial circulation in lung cancer. The proportion of the two circulations is moderately dependent on tumour size. This new technique may benefit the management of lung cancer.

Progress toward a circulation atlas for application to coastal water siting problems

NASA Technical Reports Server (NTRS)

Munday, J. C., Jr.; Gordon, H. H.

1978-01-01

Circulation data needed to resolve coastal siting problems are assembled from historical hydrographic and remote sensing studies in the form of a Circulation Atlas. Empirical data are used instead of numerical model simulations to achieve fine resolution and include fronts and convergence zones. Eulerian and Langrangian data are collected, transformed, and combined into trajectory maps and current vector maps as a function of tidal phase and wind vector. Initial Atlas development is centered on the Elizabeth River, Hampton Roads, Virgina.

Direct measurement of initial wake separation (bo) and initial circulation (ro) using pulsed lidars

DOT National Transportation Integrated Search

2013-06-17

The initial separation distance (bo) between a counter-rotating vortex pair generated by an aircraft is a fundamental parameter affecting wake turbulence decay. For the past decade Pulsed Doppler Lidars have emerged as the primary remote sensors for ...

The time course of follicle-stimulating hormone suppression by recombinant human inhibin A in the adult male rhesus monkey (Macaca mulatta).

PubMed

Ramaswamy, S; Pohl, C R; McNeilly, A S; Winters, S J; Plant, T M

1998-08-01

In higher primates, FSH secretion appears to be regulated by a control system consistent with that described by the classical inhibin hypothesis. The purpose of the present experiment was to examine the time course of inhibin's action to suppress FSH secretion in the intact adult male rhesus monkey. To this end, five adult males implanted with indwelling venous catheters and exhibiting typical episodic patterns of LH and testosterone (T) secretion received a 4-day i.v. infusion of recombinant human (rh) inhibin A (832 ng/h x kg) followed, after a 4-week interval, by vehicle infusion of similar duration. Changes in circulating FSH concentrations during the inhibin and vehicle infusions were determined using a sensitive homologous macaque RIA, whereas enzyme-linked immunosorbent assays were employed to track inhibin A, inhibin B, and inhibin pro-alpha-C levels during the experiment. Normal pulsatile activity in the hypothalamic-pituitary-Leydig cell axis was confirmed by monitoring changes in circulating concentrations of LH and T in 12-h windows of sequential blood collection (1200-2400 h; every 20 min) before, during, and after the rh inhibin A and vehicle infusions. Although infusion of rh inhibin A, which led to a 12 ng/ml square wave increment in circulating levels of this inhibin dimer, produced a marked decline in circulating FSH concentrations, significant suppression of the secretion of this gonadotropin was not manifest until 54 h after initiation of the infusion. Despite the marked decline in FSH secretion during the last 24 h of the 4-day infusion of recombinant hormone, circulating inhibin B and pro-alpha-C concentrations were maintained at preinfusion control levels (1 ng/ml). The finding that imposition of an exaggerated circulating inhibin signal led to suppression of FSH secretion in the male monkey only after 2 days of exposure to the hormone indicates that in this species the feedback action of testicular inhibin on FSH secretion is heavily lagged. Moreover, as the decrease in FSH did not lead to changes in native inhibin secretion, it seems reasonable to propose that the FSH-inhibin feedback loop that governs testicular function in higher primates operates with considerable hysteresis at both the pituitary and gonadal levels. The failure of dramatically elevated inhibin A levels to influence the pulsatile secretion of LH in the monkey reinforces the idea that in this species the pituitary action of testicular inhibin is specific for FSH and does not involve modulation of GnRH receptor levels.

Circulating a Good Service Model at Its Core: Circulation!

ERIC Educational Resources Information Center

Hernandez, Edmee Sofia; Germain, Carol Anne, Ed.

2009-01-01

Circulation is the library's tireless foot soldier: it serves as the front gate to the library's services and resources. This service point is where most patrons enter and leave; and experience their first and last impressions--impressions that linger. In an age when academic libraries are facing meager budgets and declining usage statistics, this…

A Non-Lethal Traumatic/Hemorrhagic Insult Strongly Modulates the Compartment-Specific PAI-1 Response in the Subsequent Polymicrobial Sepsis

PubMed Central

Raeven, Pierre; Salibasic, Alma; Drechsler, Susanne; Weixelbaumer, Katrin Maria; Jafarmadar, Mohammad; van Griensven, Martijn; Bahrami, Soheyl; Osuchowski, Marcin Filip

2013-01-01

Introduction Plasminogen activator inhibitor 1 (PAI-1) is a key factor in trauma- and sepsis-induced coagulopathy. We examined how trauma-hemorrhage (TH) modulates PAI-1 responses in subsequent cecal ligation and puncture (CLP)-induced sepsis, and the association of PAI-1 with septic outcomes. Methods Mice underwent TH and CLP 48 h later in three separate experiments. In experiment 1, mice were sacrificed pre- and post-CLP to characterize the trajectory of PAI-1 in plasma (protein) and tissues (mRNA). Post-CLP dynamics in TH-CLP (this study) and CLP-Only mice (prior study) were then compared for modulatory effects of TH. In experiment 2, to relate PAI-1 changes to outcome, mice underwent TH-CLP and were sampled daily and followed for 14 days to compare non-survivors (DEAD) and survivors (SUR). In experiment 3, plasma and tissue PAI-1 expression were compared between mice predicted to die (P-DIE) and to live (P-LIVE). Results In experiment 1, an early post-TH rise of circulating PAI-1 was contrasted by a delayed (post-TH) decrease of PAI-1 mRNA in organs. In the post-CLP phase, profiles of circulating PAI-1 were similar between TH-CLP and CLP-Only mice. Conversely, PAI-1 mRNA declined in the liver and heart of TH-CLP mice versus CLP-Only. In experiment 2, there were no DEAD/SUR differences in circulating PAI-1 prior to CLP. Post-CLP, circulating PAI-1 in DEAD was 2–4-fold higher than in SUR. PAI-1 increase heralded septic deaths up to 48 h prior but DEAD/SUR thrombomodulin (endothelial injury marker) levels were identical. In experiment 3, levels of circulating PAI-1 and its hepatic gene expression were higher in P-DIE versus P-LIVE mice and those increases closely correlated with liver dysfunction. Conclusions Trauma modulated septic PAI-1 responses in a compartment-specific fashion. Only post-CLP increases in circulating PAI-1 predicted septic outcomes. In posttraumatic sepsis, pre-lethal release of PAI-1 was mostly of hepatic origin and was independent of endothelial injury. PMID:23408987

A retrospective analysis of negative diffusion-weighted image results in patients with acute cerebral infarction

PubMed Central

Zuo, Lian; Zhang, Yue; Xu, Xiahong; Li, Ying; Bao, Huan; Hao, Junjie; Wang, Xin; Li, Gang

2015-01-01

We aimed to investigate the clinicoradiologic determinants of negative diffusion-weighted image (DWI) results in patients with acute cerebral infarction (ACI). The medical records were reviewed of ACI patients. Patients were divided to the DWI positive and negative group. Positive DWI was used as independent variable and patients' clinicoradiologic factors were used as co-variables for multivariate logistic regression analysis. 349 patients received initial cerebral MRI within 72 hours of admission. Lacunar infarction was most common (42.1%) followed by posterior circulation infarction (30.1%) and partial anterior circulation infarction (18.1%). The majority of the patients (72.2%) had an NIHSS score of less than 5 at admission. 316 patients (90.54%) were positive on initial DWI. Patients with smoking, initial SBP ≥ 140 or DBP ≥ 90 mmHg, initial fasting plasma glucose (FPG) ≥7.0 mmol/L, initial MRI from onset of disease >1 d and anterior circulation infarction were liable to show positive DWI. Furthermore, DWI negative patients had significantly lower NIHSS scores (IQR 0,1,2) than DWI positive patients (IQR 1,2,4) (P = 0.000) at two weeks post onset of acute cerebral infarction. In conclusion, multiple clinicoradiologic factors are associated with negative and positive DWI and further delineation of these factors is required in future prospective studies. PMID:25777182

In vitro microfluidic circulatory system for circulating cancer cells

PubMed Central

wan, jiandi; Fan, Rong; Emery, Travis; Zhang, Yongguo; Xia, Yuxuan; Sun, Jun; Wan, Jiandi

2016-01-01

Circulating tumor cells (CTCs) experience hemodynamic shear stress in circulation and play critical roles in cancer metastasis. The effect of shear on CTCs, however, remains less studied. Here, we described a protocol to circulate HCT116 human colon cancer cells in a microfluidic circulatory system mimicking physiologically relevant circulating conditions. This protocol represents a useful scaffold to mimic the transportation of CTCs in circulation and thus provides an effective means to study the effect of shear on CTCs. We anticipate that future studies using the developed system will help us to further investigate the regulatory roles of shear in molecular responses of CTCs. PMID:28690779

First Tracer Test After Circulation in Desert Peak 27-15

DOE Data Explorer

Rose, Peter

2013-11-16

Following the successful stimulation of Desert Peak target EGS well 27-15, a circulation test was initiated by injecting a conservative tracer (1,5-nds) in combination with a reactive tracer (7-amino-1,3-naphthalene disulfonate). The closest production well 74-21 was monitored over the subsequent several months.

Control method for mixed refrigerant based natural gas liquefier

DOEpatents

Kountz, Kenneth J.; Bishop, Patrick M.

2003-01-01

In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig. Refrigerant vapor is introduced from the refrigerant holding tank into the refrigerant circulation circuit until the suction pressure is reduced to below about 15 psig, after which flow of the refrigerant vapor from the refrigerant holding tank is terminated. Natural gas is then introduced into a natural gas liquefier, resulting in liquefaction of the natural gas.

Development of the probability of return of spontaneous circulation in intervals without chest compressions during out-of-hospital cardiac arrest: an observational study.

PubMed

Gundersen, Kenneth; Kvaløy, Jan Terje; Kramer-Johansen, Jo; Steen, Petter Andreas; Eftestøl, Trygve

2009-02-06

One of the factors that limits survival from out-of-hospital cardiac arrest is the interruption of chest compressions. During ventricular fibrillation and tachycardia the electrocardiogram reflects the probability of return of spontaneous circulation associated with defibrillation. We have used this in the current study to quantify in detail the effects of interrupting chest compressions. From an electrocardiogram database we identified all intervals without chest compressions that followed an interval with compressions, and where the patients had ventricular fibrillation or tachycardia. By calculating the mean-slope (a predictor of the return of spontaneous circulation) of the electrocardiogram for each 2-second window, and using a linear mixed-effects statistical model, we quantified the decline of mean-slope with time. Further, a mapping from mean-slope to probability of return of spontaneous circulation was obtained from a second dataset and using this we were able to estimate the expected development of the probability of return of spontaneous circulation for cases at different levels. From 911 intervals without chest compressions, 5138 analysis windows were identified. The results show that cases with the probability of return of spontaneous circulation values 0.35, 0.1 and 0.05, 3 seconds into an interval in the mean will have probability of return of spontaneous circulation values 0.26 (0.24-0.29), 0.077 (0.070-0.085) and 0.040(0.036-0.045), respectively, 27 seconds into the interval (95% confidence intervals in parenthesis). During pre-shock pauses in chest compressions mean probability of return of spontaneous circulation decreases in a steady manner for cases at all initial levels. Regardless of initial level there is a relative decrease in the probability of return of spontaneous circulation of about 23% from 3 to 27 seconds into such a pause.

Exploring the Circulation Dynamics of Mississippi Sound and Bight Using the CONCORDE Synthesis Model

NASA Astrophysics Data System (ADS)

Pan, C.; Dinniman, M. S.; Fitzpatrick, P. J.; Lau, Y.; Cambazoglu, M. K.; Parra, S. M.; Hofmann, E. E.; Dzwonkowski, B.; Warner, S. J.; O'Brien, S. J.; Dykstra, S. L.; Wiggert, J. D.

2017-12-01

As part of the modeling effort of the GOMRI (Gulf of Mexico Research Initiative)-funded CONCORDE consortium, a high resolution ( 400 m) regional ocean model is implemented for the Mississippi (MS) Sound and Bight. The model is based on the Coupled Ocean Atmosphere Wave Sediment Transport Modeling System (COAWST), with initial and lateral boundary conditions drawn from data assimilative 3-day forecasts of the 1km-resolution Gulf of Mexico Navy Coastal Ocean Model (GOM-NCOM). The model initiates on 01/01/2014 and runs for 3 years. The model results are validated with available remote sensing data and with CONCORDE's moored and ship-based in-situ observations. Results from a three-year simulation (2014-2016) show that ocean circulation and water properties of the MS Sound and Bight are sensitive to meteorological forcing. A low resolution surface forcing, drawn from the North America Regional Reanalysis (NARR), and a high resolution forcing, called CONCORDE Meteorological Analysis (CMA) ) that resolves the diurnal sea breeze, are used to drive the model to examine the sensitivity of the circulation to surface forcing. The model responses to the low resolution NARR forcing and to the high resolution CMA are compared in detail for the CONCORDE Fall and Spring field campaigns when contemporaneous in situ data are available, with a focus on how simulated exchanges between MS Sound and MS Bight are impacted. In most cases, the model shows higher simulation skill when it is driven by CMA. Freshwater plumes of the MS River, MS Sound and Mobile Bay influence the shelf waters of the MS Bight in terms of material budget and dynamics. Drifters and dye experiments near Mobile Bay demonstrate that material exchanges between Mobile Bay and the Sound, and between the Sound and Bight, are sensitive to the wind strength and direction. A model - data comparison targeting the Mobile Bay plume suggests that under both northerly and southerly wind conditions the model is capable of simulating the variation of the plume in terms of velocity, plume extent, heat and salt budgets.

Optimization of EGFR high positive cell isolation procedure by design of experiments methodology.

PubMed

Levi, Ofer; Tal, Baruch; Hileli, Sagi; Shapira, Assaf; Benhar, Itai; Grabov, Pavel; Eliaz, Noam

2015-01-01

Circulating tumor cells (CTCs) in blood circulation may play a role in monitoring and even in early detection of metastasis patients. Due to the limited presence of CTCs in blood circulation, viable CTCs isolation technology must supply a very high recovery rate. Here, we implement design of experiments (DOE) methodology in order to optimize the Bio-Ferrography (BF) immunomagnetic isolation (IMI) procedure for the EGFR high positive CTCs application. All consequent DOE phases such as screening design, optimization experiments and validation experiments were used. A significant recovery rate of more than 95% was achieved while isolating 100 EGFR high positive CTCs from 1 mL human whole blood. The recovery achievement in this research positions BF technology as one of the most efficient IMI technologies, which is ready to be challenged with patients' blood samples. © 2015 International Clinical Cytometry Society.

Sediment dynamics in the Adriatic Sea investigated with coupled models

USGS Publications Warehouse

Sherwood, Christopher R.; Book, Jeffrey W.; Carniel, Sandro; Cavaleri, Luigi; Chiggiato, Jacopo; Das, Himangshu; Doyle, James D.; Harris, Courtney K.; Niedoroda, Alan W.; Perkins, Henry; Poulain, Pierre-Marie; Pullen, Julie; Reed, Christopher W.; Russo, Aniello; Sclavo, Mauro; Signell, Richard P.; Traykovski, Peter A.; Warner, John C.

2004-01-01

Several large research programs focused on the Adriatic Sea in winter 2002-2003, making it an exciting place for sediment dynamics modelers (Figure 1). Investigations of atmospheric forcing and oceanic response (including wave generation and propagation, water-mass formation, stratification, and circulation), suspended material, bottom boundary layer dynamics, bottom sediment, and small-scale stratigraphy were performed by European and North American researchers participating in several projects. The goal of EuroSTRATAFORM researchers is to improve our ability to understand and simulate the physical processes that deliver sediment to the marine environment and generate stratigraphic signatures. Scientists involved in the Po and Apennine Sediment Transport and Accumulation (PASTA) experiment benefited from other major research programs including ACE (Adriatic Circulation Experiment), DOLCE VITA (Dynamics of Localized Currents and Eddy Variability in the Adriatic), EACE (the Croatian East Adriatic Circulation Experiment project), WISE (West Istria Experiment), and ADRICOSM (Italian nowcasting and forecasting) studies.

L-1011 aircraft carrying a Pegasus XL (SORCE)

NASA Image and Video Library

2003-01-25

The L-1011 aircraft carrying a Pegasus XL rocket with NASA's Solar Radiation and Climate Experiment (SORCE) attached takes off from Cape Canaveral Air Force Station, Fla. The L-1011 will release the rocket over the Atlantic Ocean at 39,000 feet. After separation from the rocket, initial contact with the satellite will be made and the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado.

KSC-03pd0184

NASA Image and Video Library

2003-01-25

KENNEDY SPACE CENTER, FLA. -- -- The L-1011 aircraft carrying a Pegasus XL rocket with NASA's Solar Radiation and Climate Experiment (SORCE) is seen after takeoff off from Cape Canaveral Air Force Station, Fla. The L-1011 will release the rocket over the Atlantic Ocean at 39,000 feet. After separation from the rocket, initial contact with the satellite will be made and the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado.

Effects of syndyphalin-33 on feed intake and circulating measures of growth hormone, cortisol, and immune cell populations in the recently-weaned pig

USDA-ARS?s Scientific Manuscript database

The synthetic met-enkephalin syndyphalin-33 (SD-33) increases feed intake in sheep and transiently increases circulating growth hormone (GH) concentrations in sheep, rats, and pigs. Two experiments were performed to evaluate the effects of SD-33 on recently-weaned pigs. In a preliminary experiment, ...

Feature-oriented regional modeling and simulations in the Gulf of Maine and Georges Bank

NASA Astrophysics Data System (ADS)

Gangopadhyay, Avijit; Robinson, Allan R.; Haley, Patrick J.; Leslie, Wayne G.; Lozano, Carlos J.; Bisagni, James J.; Yu, Zhitao

2003-03-01

The multiscale synoptic circulation system in the Gulf of Maine and Georges Bank (GOMGB) region is presented using a feature-oriented approach. Prevalent synoptic circulation structures, or 'features', are identified from previous observational studies. These features include the buoyancy-driven Maine Coastal Current, the Georges Bank anticyclonic frontal circulation system, the basin-scale cyclonic gyres (Jordan, Georges and Wilkinson), the deep inflow through the Northeast Channel (NEC), the shallow outflow via the Great South Channel (GSC), and the shelf-slope front (SSF). Their synoptic water-mass ( T- S) structures are characterized and parameterized in a generalized formulation to develop temperature-salinity feature models. A synoptic initialization scheme for feature-oriented regional modeling and simulation (FORMS) of the circulation in the coastal-to-deep region of the GOMGB system is then developed. First, the temperature and salinity feature-model profiles are placed on a regional circulation template and then objectively analyzed with appropriate background climatology in the coastal region. Furthermore, these fields are melded with adjacent deep-ocean regional circulation (Gulf Stream Meander and Ring region) along and across the SSF. These initialization fields are then used for dynamical simulations via the primitive equation model. Simulation results are analyzed to calibrate the multiparameter feature-oriented modeling system. Experimental short-term synoptic simulations are presented for multiple resolutions in different regions with and without atmospheric forcing. The presented 'generic and portable' methodology demonstrates the potential of applying similar FORMS in many other regions of the Global Coastal Ocean.

Insights Into Circulating Cytokine Dynamics during Pregnancy in HIV-Infected Beninese Exposed to Plasmodium falciparum Malaria

PubMed Central

Ibitokou, Samad A.; Denoeud-Ndam, Lise; Ezinmegnon, Sèm; Ladékpo, Rodolphe; Zannou, Djimon-Marcel; Massougbodji, Achille; Girard, Pierre-Marie; Cot, Michel; Luty, Adrian J. F.; Ndam, Nicaise Tuikue

2015-01-01

We investigated the circulating plasma levels of Th1- (Interleukin-2 [IL-2], tumor necrosis factor-α [TNF-α], interferon-gamma [IFN-γ]) and Th2-type (IL-4, IL-5, IL-10) cytokines in human immunodeficiency virus (HIV)-infected pregnant women living in a malaria-endemic area. We analyzed samples from 200 pregnant women included in the prevention of pregnancy-associated malaria in HIV-infected women: cotrimoxazole prophylaxis versus mefloquine (PACOME) clinical trial who were followed until delivery. Cytokine concentrations were measured by flow cytometry-based multiplex bead array. Significantly elevated levels of IL-10 and lower levels of TNF-α were observed at delivery compared with inclusion (P = 0.005). At inclusion, the presence of circulating IFN-γ, a higher CD4+ T cell count and having initiated intermittent preventive treatment of malaria with sulfadoxine pyrimethamine (SP-IPTp) were all associated with a lower likelihood of Plasmodium falciparum infection. At delivery, the inverse relationship between the presence of infection and circulating IFN-γ persisted, although there was a positive association between the likelihood of infection and the presence of circulating TNF-α. Initiation of antiretroviral therapy was associated with elevated IL-5 production. Consistent with our own and others' observations in HIV seronegative subjects, this study shows circulating IL-10 to be a marker of infection with P. falciparum during pregnancy even in HIV-infected women, although plasma IFN-γ may be a marker of anti-malarial protection in such women. PMID:26101276

[Study on the law of circulation of meridians].

PubMed

Wang, Hong-mo

2005-03-01

To study the basic law of circulation of channels and collaterals. Inherit and develop ripe experiences of predecessors based on The Yellow Emperor's Internal Classic and other classic medical books. Circulation of channels and collaterals has the eight laws, including naming law, distribution law, converging law, exterior-interior association law, beginning-ending running law, meridian-qi bidirectional circulation law, zang- and fu-organ pathway liaison law, and liaison law of connecting with trunks and sense organs.

The Impact of Gulf Stream-Induced Diabatic Forcing on Coastal Mid-Atlantic Surface Cyclogenesis

NASA Astrophysics Data System (ADS)

Cione, Joseph Jerome

In this dissertation, numerical experiments were conducted using a mesoscale atmospheric model developed at North Carolina State University. Three sets of numerical experiments were conducted and were designed to: quantify the impact Gulf Stream frontal distance, initial surface air temperature and cold air outbreak timing each have on the subsequent development of the marine atmospheric boundary layer during periods of offshore cold advection; investigate critical processes associated with Gulf Stream -induced mesocyclogenesis and; elucidate the role SST gradients and surface fluxes of heat and moisture have on the intensification and track of propagating mesocyclonic systems within the highly baroclinic Gulf Stream region. A major finding from the offshore cold advection simulations is that the initial air-sea contrast is the dominant forcing mechanism linked to the offshore circulation development and marine boundary layer modification. Results from the mesocyclogenesis experiments indicate that surface cyclogenesis was simulated to occur along a Gulf Stream meander in a region where the gradients in sea surface temperature (SST) were maximized. Results from sensitivity experiments illustrate that changes in the Gulf Stream SST gradient pattern can act to alter the timing and degree of cyclonic development simulated, while the inclusion of surface fluxes and moist convective processes during the development phase act to strongly enhance the intensity and/or occurrence of simulated mesocyclogenesis. Both observational and numerical results from studies investigating the impact strong Gulf Stream SST gradients have on the development of pre-existing, propagating cyclonic systems show that the baroclinic nature of the low level environment near the circulation center (as well as the degree of simulated/observed surface cyclonic intensification) appear to be highly dependent upon the mesoscale storm track within the Gulf Stream frontal zone. Furthermore, the numerical storm track experiments conducted in this research illustrate that surfaces fluxes can act to significantly alter the storm track of the surface mesocyclone (in addition to impacting the overall intensification of the simulated cyclonic system). This work also presents the technique development and operational utilization of the recently devised Atlantic Surface Cyclone Intensification Index (ASCII). The index continues to be implemented by the National Weather Service at the Raleigh-Durham and surrounding coastal forecast offices, and to date, has been successfully utilized for 11 coastal winter storm events over the February 1994-January 1996 period.

A table top experiment to study plasma confined by a dipole magnet

NASA Astrophysics Data System (ADS)

Bhattacharjee, Sudeep; Baitha, Anuj Ram

2016-10-01

There has been a long quest to understand charged particle generation, confinement and underlying complex processes in a plasma confined by a dipole magnet. Our earth's magnetosphere is an example of such a naturally occurring system. A few laboratory experiments have been designed for such investigations, such as the Levitated Dipole Experiment (LDX) at MIT, the Terella experiment at Columbia university, and the Ring Trap-1 (RT-1) experiment at the University of Tokyo. However, these are large scale experiments, where the dipole magnetic field is created with superconducting coils, thereby, necessitating power supplies and stringent cryogenic requirements. We report a table top experiment to investigate important physical processes in a dipole plasma. A strong cylindrical permanent magnet, is employed to create the dipole field inside a vacuum chamber. The magnet is suspended and cooled by circulating chilled water. The plasma is heated by electromagnetic waves of 2.45 GHz and a second frequency in the range 6 - 11 GHz. Some of the initial results of measurements and numerical simulation of magnetic field, visual observations of the first plasma, and spatial measurements of plasma parameters will be presented.

Association of circulating active and total ghrelin concentrations with dry matter intake, growth, and carcass characteristics of finishing beef cattle

USDA-ARS?s Scientific Manuscript database

Ghrelin is a gut peptide that when acylated is thought to stimulate appetite. Circulating ghrelin concentrations could potentially be used as a predictor of DMI in cattle. The objective of this experiment was to determine the association of circulating ghrelin concentrations with DMI and other produ...

Glider Observations of Circulation Around an Island

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Glider Observations of Circulation Around an Island...of island circulation through observations using underwater gliders , with the ultimate goal of better prediction. OBJECTIVES Given a goal of...APPROACH We are making Spray glider observations from Palau to resolve the phenomena described above. We have extensive experience deploying

Beyond "Classroom" Technology: The Equipment Circulation Program at Rasmuson Library, University of Alaska Fairbanks

ERIC Educational Resources Information Center

Jensen, Karen

2008-01-01

The library at the University of Alaska Fairbanks offers a unique equipment lending program through its Circulation Desk. The program features a wide array of equipment types, generous circulation policies, and unrestricted borrowing, enabling students, staff, and faculty to experiment with the latest in audio, video, and computer technologies,…

Thermal circulation patterns and turbulent fluxes along steep mountain slopes

NASA Astrophysics Data System (ADS)

Nadeau, D. F.; Pardyjak, E.; Higgins, C. W.; Huwald, H.; Baerenbold, F.; Parlange, M. B.

2010-12-01

In hydrology, it is crucial to understand the atmospheric flow dynamics in mountainous terrain to predict turbulent exchanges of heat and moisture accurately at the regional scale. Under clear sky and weak synoptic conditions, these land-atmosphere interactions are driven by thermal circulations that take place over a strong diurnal cycle. During the day, winds travel up the mountain slopes and at night, they travel down toward to the bottom of the valley. Little is known about how the transition between these two regimes takes place over steep slopes. The Slope Experiment at La Fouly (SELF) in the Swiss Alps was designed to investigate these transition periods throughout summer 2010. In this paper, we will present the first results obtained from this field campaign. Data from a network of 16 wireless surface stations is used to define catchment wide micrometeorological processes such as slope and valley wind system development, while detailed measurements of the turbulent processes on a steep idealized slope (20 to 45 degrees) were also made. The slope was instrumented along a transect with four towers (including a surface energy budget station and 10 m tower with sonic anemometers), 13 surface temperature measurement stations and a tethered balloon system to capture the complex interplay between surface and atmosphere. Initial data presented will include basic circulation pattern development and measurements of the turbulent fluxes of water vapor, heat and momentum on the slope.

Sensitivity of soil moisture initialization for decadal predictions under different regional climatic conditions in Europe

NASA Astrophysics Data System (ADS)

Khodayar, S.; Sehlinger, A.; Feldmann, H.; Kottmeier, C.

2015-12-01

The impact of soil initialization is investigated through perturbation simulations with the regional climate model COSMO-CLM. The focus of the investigation is to assess the sensitivity of simulated extreme periods, dry and wet, to soil moisture initialization in different climatic regions over Europe and to establish the necessary spin up time within the framework of decadal predictions for these regions. Sensitivity experiments consisted of a reference simulation from 1968 to 1999 and 5 simulations from 1972 to 1983. The Effective Drought Index (EDI) is used to select and quantify drought status in the reference run to establish the simulation time period for the sensitivity experiments. Different soil initialization procedures are investigated. The sensitivity of the decadal predictions to soil moisture initial conditions is investigated through the analysis of water cycle components' (WCC) variability. In an episodic time scale the local effects of soil moisture on the boundary-layer and the propagated effects on the large-scale dynamics are analysed. The results show: (a) COSMO-CLM reproduces the observed features of the drought index. (b) Soil moisture initialization exerts a relevant impact on WCC, e.g., precipitation distribution and intensity. (c) Regional characteristics strongly impact the response of the WCC. Precipitation and evapotranspiration deviations are larger for humid regions. (d) The initial soil conditions (wet/dry), the regional characteristics (humid/dry) and the annual period (wet/dry) play a key role in the time that soil needs to restore quasi-equilibrium and the impact on the atmospheric conditions. Humid areas, and for all regions, a humid initialization, exhibit shorter spin up times, also soil reacts more sensitive when initialised during dry periods. (e) The initial soil perturbation may markedly modify atmospheric pressure field, wind circulation systems and atmospheric water vapour distribution affecting atmospheric stability conditions, thus modifying precipitation intensity and distribution even several years after the initialization.

CFD validation experiments at the Lockheed-Georgia Company

NASA Technical Reports Server (NTRS)

Malone, John B.; Thomas, Andrew S. W.

1987-01-01

Information is given in viewgraph form on computational fluid dynamics (CFD) validation experiments at the Lockheed-Georgia Company. Topics covered include validation experiments on a generic fighter configuration, a transport configuration, and a generic hypersonic vehicle configuration; computational procedures; surface and pressure measurements on wings; laser velocimeter measurements of a multi-element airfoil system; the flowfield around a stiffened airfoil; laser velocimeter surveys of a circulation control wing; circulation control for high lift; and high angle of attack aerodynamic evaluations.

Mixing-induced fluid destratification and ullage condensation

NASA Technical Reports Server (NTRS)

Meserole, Jere S.; Jones, Ogden S.; Fortini, Anthony F.

1987-01-01

In many applications, on-orbit storage and transfer of cryogens will require forced mixing to control tank pressure without direct venting to space. During a no-vent transfer or during operation of a thermodynamic vent system in a cryogen storage tank, pressure control is achieved by circulating cool liquid to the liquid-vapor interface to condense some of the ullage vapor. To measure the pressure and temperature response rates in mixing-induced condensation, an experiment has been developed using Freon 11 to simulate the two-phase behavior of a cryogen. A thin layer at the liquid surface is heated to raise the tank pressure, and then a jet mixer is turned on to circulate the liquid, cool the surface, and reduce the pressure. Many nozzle configurations and flow rates are used. Tank pressure and the temperature profiles in the ullage and the liquid are measured. Initial data from this ground test are shown correlated with normal-gravity and drop-tower dye-mixing data. Pressure collapse times are comparable to the dye-mixing times, whereas the times needed for complete thermal mixing are much longer than the dye-mixing times.

Impact of soil moisture initialization on boreal summer subseasonal forecasts: mid-latitude surface air temperature and heat wave events

NASA Astrophysics Data System (ADS)

Seo, Eunkyo; Lee, Myong-In; Jeong, Jee-Hoon; Koster, Randal D.; Schubert, Siegfried D.; Kim, Hye-Mi; Kim, Daehyun; Kang, Hyun-Suk; Kim, Hyun-Kyung; MacLachlan, Craig; Scaife, Adam A.

2018-05-01

This study uses a global land-atmosphere coupled model, the land-atmosphere component of the Global Seasonal Forecast System version 5, to quantify the degree to which soil moisture initialization could potentially enhance boreal summer surface air temperature forecast skill. Two sets of hindcast experiments are performed by prescribing the observed sea surface temperature as the boundary condition for a 15-year period (1996-2010). In one set of the hindcast experiments (noINIT), the initial soil moisture conditions are randomly taken from a long-term simulation. In the other set (INIT), the initial soil moisture conditions are taken from an observation-driven offline Land Surface Model (LSM) simulation. The soil moisture conditions from the offline LSM simulation are calibrated using the forecast model statistics to minimize the inconsistency between the LSM and the land-atmosphere coupled model in their mean and variability. Results show a higher boreal summer surface air temperature prediction skill in INIT than in noINIT, demonstrating the potential benefit from an accurate soil moisture initialization. The forecast skill enhancement appears especially in the areas in which the evaporative fraction—the ratio of surface latent heat flux to net surface incoming radiation—is sensitive to soil moisture amount. These areas lie in the transitional regime between humid and arid climates. Examination of the extreme 2003 European and 2010 Russian heat wave events reveal that the regionally anomalous soil moisture conditions during the events played an important role in maintaining the stationary circulation anomalies, especially those near the surface.

Numerical simulation of the circulation of the atmosphere of Titan

NASA Technical Reports Server (NTRS)

Hourdin, F.; Levan, P.; Talagrand, O.; Courtin, Regis; Gautier, Daniel; Mckay, Christopher P.

1992-01-01

A three dimensional General Circulation Model (GCM) of Titan's atmosphere is described. Initial results obtained with an economical two dimensional (2D) axisymmetric version of the model presented a strong superrotation in the upper stratosphere. Because of this result, a more general numerical study of superrotation was started with a somewhat different version of the GCM. It appears that for a slowly rotating planet which strongly absorbs solar radiation, circulation is dominated by global equator to pole Hadley circulation and strong superrotation. The theoretical study of this superrotation is discussed. It is also shown that 2D simulations systemically lead to instabilities which make 2D models poorly adapted to numerical simulation of Titan's (or Venus) atmosphere.

Clarifying the Dynamics of the General Circulation: Phillips's 1956 Experiment.

NASA Astrophysics Data System (ADS)

Lewis, John M.

1998-01-01

In the mid-1950s, amid heated debate over the physical mechanisms that controlled the known features of the atmosphere's general circulation, Norman Phillips simulated hemispheric motion on the high-speed computer at the Institute for Advanced Study. A simple energetically consistent model was integrated for a simulated time of approximately 1 month. Analysis of the model results clarified the respective roles of the synoptic-scale eddies (cyclones-anticyclones) and mean meridional circulation in the maintenance of the upper-level westerlies and the surface wind regimes. Furthermore, the modeled cyclones clearly linked surface frontogenesis with the upper-level Charney-Eady wave. In addition to discussing the model results in light of the controversy and ferment that surrounded general circulation theory in the 1940s-1950s, an effort is made to follow Phillips's scientific path to the experiment.

The effect of local circulations on the variation of atmospheric pollutants in the northwestern Taiwan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pay-Liam Lin; Hsin-Chih Lai

1996-12-31

A field experiment was held in the northwestern Taiwan as a part of a long-term research program for studying Taiwan`s local circulation. The program has been named as Taiwan Regional-circulation Experiment (TREX). The particular goal of this research is to investigate characteristics of boundary layer and local Circulation and their impact on the distribution and Variation of pollutants in the northwestern Taiwan during Mei-Yu season. It has been known for quite sometime that land-sea breeze is very pronounced under hot and humid conditions. Extensive network includes 11 pilot ballon stations, 3 acoustic sounding sites, and 14 surface stations in aboutmore » 20 km by 20 km area centered at National Central University, Chung-Li. In addition, there are ground temperature measurements at 3 sites, Integrated Sounding System (ISS) at NCU, air plane observation, tracer experiment with 10 collecting stations, 3 background upper-air sounding stations, 2 towers etc. NOAA and GMS satellite data, sea surface temperature radar, and precipitation data are collected. The local circulations such as land/sea breezes and mountain/valley winds, induced by thermal and topographical effects often play an important role in transporting, redistributing and transforming atmospheric pollutants. This study documents the effects of the development of local circulations and the accompanying evolution of boundary layer on the distribution and the variation of the atmospheric pollutants in the north western Taiwan during Mei-Yu season.« less

Analysis of altimeter data jointly with seafloor electric data (vertically integrated velocity) and VCTD-yoyo data (detailed profiles of VCTD)

NASA Technical Reports Server (NTRS)

Tarits, Pascal D.; Menvielle, M.; Provost, C.; Filloux, J. H.

1991-01-01

We propose simultaneous analyses of the TOPEX/POSEIDON altimetry data, in situ data--mainly permanent seafloor electric recordings--and velocity, conductivity, temperature, density (VCTD)-yoyo data at several stations in areas of scientific interest. We are planning experiments in various areas of low and high energy levels. Several complementary and redundant methods will be used to characterize the ocean circulation and its short- and long-term variability. We shall emphasize long-term measurement using permanent stations. Our major initial objectives with the TOPEX/POSEIDON mission are the Confluence area in the Argentine Basin and the Circumpolar Antarctic Current. An early experiment was carried out in the Confluence zone in 1988 and 1990 (Confluence Principal Investigators, 1990) to prepare for an intensive phase later one. This intensive phase will include new types of instrumentation. Preliminary experiments will be carried out in the Mediterranean Sea (in 1991) and in the North Atlantic Ocean (in 1992, north of the Canary Islands) to test the new instrumentation.

Ship wakes and their manifestations on the sea surface

NASA Astrophysics Data System (ADS)

Ermakov, Stanislav; Kapustin, Ivan; Kalimulin, Rashid

2013-04-01

Spatial/temporal evolution of turbulence generated by surface ships and the effect of the wake on short wind waves has been studied on the Black Sea and on the Gorky Water Reservoir. Measurements of currents in ship wakes were conducted using an Acoustic Doppler Current Profiler deployed from a motor boat. It was obtained that the temporal/spatial evolution of the wake width could be described approximately by a 0.4-power dependence, and the wake depth remained nearly constant at its initial stage. This allowed one to consider the wake widening as a one-dimensional process. We have developed a simple one-dimensional model of ship wake evolution using a semi-empirical theory of turbulence, and the initial stage of the wake widening (when neglecting dissipation) was described by the equation of turbulent energy balance with the pulse initial condition. Mean circulating currents in the wake zone resulting in the wind wave intensification ("suloi" areas) at the boundaries of the wake were detected in experiment. The asymmetry of the "suloi" bands was observed when the wind was blowing nearly perpendicular to the wake axis. It was shown that the later stage of the wake evolution is characterized by the formation of slick bands at the edges of the wake. The slick bands is a result of the transport of surfactants to the water surface by air bubbles in the wake and their compression due to the mean circulating currents. The work was supported by RFBR (projects 12-05-31237, 11-05-00295), the Program RAN Radiophysics, and by the Russian Government (Grants No. 11.G34.31.0048 and 11.G34.31.0078).

Genesis of Pre-Hurricane Felix (2007). Part 2; Warm Core Formation, Precipitation Evolution, and Predictability

NASA Technical Reports Server (NTRS)

Wang, zhuo; Montgomery M. T.; Dunkerton, T. J.

2010-01-01

This is the second of a two-part study examining the simulated formation of Atlantic Hurricane Felix (2007) in a cloud-representing framework. Here several open issues are addressed concerning the formation of the storm's warm core, the evolution and respective contribution of stratiform versus convective precipitation within the parent wave's pouch, and the sensitivity of the development pathway reported in Part I to different model physics options and initial conditions. All but one of the experiments include ice microphysics as represented by one of several parameterizations, and the partition of convective versus stratiform precipitation is accomplished using a standard numerical technique based on the high-resolution control experiment. The transition to a warm-core tropical cyclone from an initially cold-core, lower tropospheric wave disturbance is analyzed first. As part of this transformation process, it is shown that deep moist convection is sustained near the pouch center. Both convective and stratiform precipitation rates increase with time. While stratiform precipitation occupies a larger area even at the tropical storm stage, deep moist convection makes a comparable contribution to the total rain rate at the pregenesis stage, and a larger contribution than stratiform processes at the storm stage. The convergence profile averaged near the pouch center is found to become dominantly convective with increasing deep moist convective activity there. Low-level convergence forced by interior diabatic heating plays a key role in forming and intensifying the near-surface closed circulation, while the midlevel convergence associated with stratiform precipitation helps to increase the midlevel circulation and thereby contributes to the formation and upward extension of a tropospheric-deep cyclonic vortex. Sensitivity tests with different model physics options and initial conditions demonstrate a similar pregenesis evolution. These tests suggest that the genesis location of a tropical storm is largely controlled by the parent wave's critical layer, whereas the genesis time and intensity of the protovortex depend on the details of the mesoscale organization, which is less predictable. Some implications of the findings are discussed.

Seasonal predictability of Arctic Sea Ice: assessing its limits and potential in a GCM and implications for observations.

NASA Astrophysics Data System (ADS)

Blanchard-Wrigglesworth, E.

2012-12-01

Arctic sea ice has exhibited a dramatic decrease both in area and thickness over the recent decades, particularly during the summer months. This decrease has led to growing interest in the potential predictability of summer sea ice, spurred in part by the socioeconomic implications. Here we present results of several parallel experiments designed to assess and understand the limits and potential for seasonal predictability of Arctic sea ice, with an emphasis on the summer minimum. Building on our experience from the SEARCH Outlook, we present results of a coupled general circulation model (GCM) hindcast simulation of Arctic summer sea ice variability for the satellite period (1979-present). These are initialized with spring sea ice volume anomalies obtained from a modelling and assimilation system, considered to be a close representation of reality. We show that there is significant predictability, yet the stochastic forcing imparted mainly by the atmosphere can lead to large errors in the hindcast. The model, however, can simulate anomalous runs that lie beyond a Gaussian distribution. Additionally, we investigate the regional characteristics of predictability and its links to sea ice dynamics and the spatio-temporal behavior of sea ice anomalies. We show a distinct difference between models. Unfortunately, observational data of thickness are not yet detailed enough to assess the models. Our results indicate the potential for detailed ice thickness observations in improving regional predictability. Finally, we discuss the importance of experiment design in predictability experiments, and show that predictions made with models that have a large mean state bias in sea ice require a careful initialization in order to fully capture all initial value predictability.

The Oceanographic Multipurpose Software Environment (OMUSE v1.0)

NASA Astrophysics Data System (ADS)

Pelupessy, Inti; van Werkhoven, Ben; van Elteren, Arjen; Viebahn, Jan; Candy, Adam; Portegies Zwart, Simon; Dijkstra, Henk

2017-08-01

In this paper we present the Oceanographic Multipurpose Software Environment (OMUSE). OMUSE aims to provide a homogeneous environment for existing or newly developed numerical ocean simulation codes, simplifying their use and deployment. In this way, numerical experiments that combine ocean models representing different physics or spanning different ranges of physical scales can be easily designed. Rapid development of simulation models is made possible through the creation of simple high-level scripts. The low-level core of the abstraction in OMUSE is designed to deploy these simulations efficiently on heterogeneous high-performance computing resources. Cross-verification of simulation models with different codes and numerical methods is facilitated by the unified interface that OMUSE provides. Reproducibility in numerical experiments is fostered by allowing complex numerical experiments to be expressed in portable scripts that conform to a common OMUSE interface. Here, we present the design of OMUSE as well as the modules and model components currently included, which range from a simple conceptual quasi-geostrophic solver to the global circulation model POP (Parallel Ocean Program). The uniform access to the codes' simulation state and the extensive automation of data transfer and conversion operations aids the implementation of model couplings. We discuss the types of couplings that can be implemented using OMUSE. We also present example applications that demonstrate the straightforward model initialization and the concurrent use of data analysis tools on a running model. We give examples of multiscale and multiphysics simulations by embedding a regional ocean model into a global ocean model and by coupling a surface wave propagation model with a coastal circulation model.

Brain temperature in volunteers subjected to intranasal cooling.

PubMed

Covaciu, L; Weis, J; Bengtsson, C; Allers, M; Lunderquist, A; Ahlström, H; Rubertsson, S

2011-08-01

Intranasal cooling can be used to initiate therapeutic hypothermia. However, direct measurement of brain temperature is difficult and the intra-cerebral distribution of temperature changes with cooling is unknown. The purpose of this study was to measure the brain temperature of human volunteers subjected to intranasal cooling using non-invasive magnetic resonance (MR) methods. Intranasal balloons catheters circulated with saline at 20°C were applied for 60 min in ten awake volunteers. No sedation was used. Brain temperature changes were measured and mapped using MR spectroscopic imaging (MRSI) and phase-mapping techniques. Heart rate and blood pressure were monitored throughout the experiment. Rectal temperature was measured before and after the cooling. Mini Mental State Examination (MMSE) test and nasal inspection were done before and after the cooling. Questionnaires about the subjects' personal experience were completed after the experiment. Brain temperature decrease measured by MRSI was -1.7 ± 0.8°C and by phase-mapping -1.8 ± 0.9°C (n = 9) at the end of cooling. Spatial distribution of temperature changes was relatively uniform. Rectal temperature decreased by -0.5 ± 0.3°C (n = 5). The physiological parameters were stable and no shivering was reported. The volunteers remained alert during cooling and no cognitive dysfunctions were apparent in the MMSE test. Postcooling nasal examination detected increased nasal secretion in nine of the ten volunteers. Volunteers' acceptance of the method was good. Both MR techniques revealed brain temperature reductions after 60 min of intranasal cooling with balloons circulated with saline at 20°C in awake, unsedated volunteers.

Intercomparison of methods of coupling between convection and large-scale circulation. 1. Comparison over uniform surface conditions

DOE PAGES

Daleu, C. L.; Plant, R. S.; Woolnough, S. J.; ...

2015-10-24

Here, as part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistentmore » implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.« less

Circulating carotenoid concentrations are positively correlated with later clutch initiation in Florida Scrub-Jays (Aphelocoma coerulescens).

PubMed

Heiss, Rebecca S; Cohen, Alan A; Bowman, Reed; Boughton, Raoul K; Bridge, Eli; McGraw, Kevin J; Schoech, Stephan J

2011-02-01

Antioxidants play key roles in preventing free radical damage to various molecules, cells, and tissues, but it is not well understood how variation in antioxidant levels may relate to the reproductive success or health of wild animals. We explored the relationship between circulating antioxidant concentrations and both body condition and timing of reproduction in male and female Florida Scrub-Jays (Aphelocoma coerulescens), a cooperatively breeding passerine bird. We examined whether levels of uric acid, vitamin E, and carotenoids (all potentially important antioxidants) were linked to body condition and timing of reproduction, two measures that are directly related to reproductive success. Antioxidant concentrations were not correlated with body condition, but they were related to timing of first clutch initiation, though not always in the predicted direction. Elevated circulating levels of carotenoids were associated with delayed clutch initiation in female breeders. Relatively higher vitamin E levels in control birds were associated with earlier clutch initiation, whereas male breeders that received long-term food supplementation had elevated levels of vitamin E and delayed reproduction. Several potential explanations for the link between elevated levels of antioxidants and delayed clutch initiation are discussed. Separate explanations for each sex include, but are not limited to, oxidative stress as a result of territory defense efforts in males, different dietary regimes due to supplementation, and mobilized plasma antioxidants in females that were coping with a stressor. © 2010 Wiley-Liss, Inc.

Heterogeneity of circulating epithelial tumour cells from individual patients with respect to expression profiles and clonal growth (sphere formation) in breast cancer.

PubMed

Pizon, M; Zimon, D; Carl, S; Pachmann, U; Pachmann, K; Camara, O

2013-01-01

The detection of tumour cells circulating in the peripheral blood of patients with breast cancer is a sign that cells have been able to leave the primary tumour and survive in the circulation. However, in order to form metastases, they require additional properties such as the ability to adhere, self-renew, and grow. Here we present data that a variable fraction among the circulating tumour cells detected by the Maintrac(®) approach expresses mRNA of the stem cell gene NANOG and of the adhesion molecule vimentin and is capable of forming tumour spheres, a property ascribed to tumour-initiating cells (TICs). Between ten and 50 circulating epithelial antigen-positive cells detected by the Maintrac approach were selected randomly from each of 20 patients with breast cancer before and after surgery and were isolated using automated capillary aspiration and deposited individually onto slides for expression profiling. In addition, the circulating tumour cells were cultured without isolation among the white blood cells from 39 patients with breast cancer in different stages of disease using culture methods favouring growth of epithelial cells. Although no epithelial cell adhesion molecule (EpCAM)-positive cells expressing stem cell genes or the adhesion molecule vimentin was detected before surgery, 10%-20% of the cells were found to be positive for mRNA of these genes after surgery. Tumour spheres from circulating cells of 39 patients with different stages of breast cancer were grown without previous isolation in a fraction increasing with the aggressivity of the tumour. Here we show that among the peripherally circulating tumour cells, a variable fraction is able to express stem cell and adhesion properties and can be grown into tumour spheres, a property ascribed to cells capable of initiating tumours and metastases.

Paradoxical attenuation of leukocyte rolling in response to ischemia- reperfusion and extracorporeal blood circulation in inflamed tissue.

PubMed

Schäfer, Stephan C; Sehrt, Desiree N; Kamler, Markus; Jakob, Heinz; Lehr, Hans-Anton

2005-07-01

In contrast to acute preparations such as the exteriorized mesentery or the cremaster muscle, chronically instrumented chamber models allow one to study the microcirculation under "physiological" conditions, i.e., in the absence of trauma-induced leukocyte rolling along the venular endothelium. To underscore the importance of studying the naive microcirculation, we implanted titanium dorsal skinfold chambers in hamsters and used intravital fluorescence microscopy to study venular leukocyte rolling in response to ischemia-reperfusion injury or extracorporeal blood circulation. The experiments were performed in chambers that fulfilled all well-established criteria for a physiological microcirculation as well as in chambers that showed various extents of leukocyte rolling due to trauma, hemorrhage, or inflammation. In ideal chambers with a physiological microcirculation (<30 rolling leukocytes/mm vessel circumference in 30 s), ischemia-reperfusion injury and extracorporeal blood circulation significantly stimulated leukocyte rolling along the venular endothelium and, subsequently, firm leukocyte adhesion. In contrast, both stimuli failed to elicit leukocyte rolling in borderline chambers (30-100 leukocytes/mm), and in blatantly inflamed chambers with yet higher numbers of rolling leukocytes at baseline (>100 leukocytes/mm), we observed a paradoxical reduction of leukocyte rolling after ischemia-reperfusion injury or extracorporeal blood circulation. A similar effect was observed when we superfused leukotriene B4 (LTB4) onto the chamber tissue. The initial increase in leukocyte rolling in response to an LTB4 challenge was reversed by a second superfusion 90 min later. These observations underscore 1) the benefit of studying leukocyte-endothelial cell interaction in chronically instrumented chamber models and 2) the necessity to strictly adhere to well-established criteria of a physiological microcirculation.

Untangling the roles of wind, run-off and tides in Prince William Sound

NASA Astrophysics Data System (ADS)

Colas, François; Wang, Xiaochun; Capet, Xavier; Chao, Yi; McWilliams, James C.

2013-07-01

Prince William Sound (PWS) oceanic circulation is driven by a combination of local wind, large run-off and strong tides. Using a regional oceanic model of the Gulf of Alaska, adequately resolving the mean circulation and mesoscale eddies, we configure a series of three nested domains. The inner domain zooms in on Prince William Sound with a 1-km horizontal grid resolution. We analyze a set of four experiments with different combinations of run-off, wind and tides to demonstrate the relative influence of these forcing on the central Sound mean circulation cell and its seasonal variability. The mean circulation in the central PWS region is generally characterized by a cyclonic cell. When forced only by the wind, the circulation is cyclonic in winter and fall and strongly anticyclonic in summer. The addition of freshwater run-off greatly enhances the eddy kinetic energy in PWS partly through near-surface baroclinic instabilities. This leads to a much more intermittent circulation in the central Sound, with the presence of intense small-scale turbulence and a disappearance of the summer wind-forced anticyclonic cell. The addition of tides reduces the turbulence intensity (relatively to the experiment with run-off only), particularly in the central Sound. The generation of turbulent motions by baroclinic processes is lowered by tidal mixing and by modification of the exchange at Hinchinbrook Entrance. Tides have an overall stabilizing effect on the central Sound circulation. Tidal rectification currents help maintain a mean cyclonic circulation throughout the year.

Circulation of Endemic Type 2 Vaccine-Derived Poliovirus in Egypt from 1983 to 1993

PubMed Central

Yang, Chen-Fu; Naguib, Tary; Yang, Su-Ju; Nasr, Eman; Jorba, Jaume; Ahmed, Nahed; Campagnoli, Ray; van der Avoort, Harrie; Shimizu, Hiroyuki; Yoneyama, Tetsuo; Miyamura, Tatsuo; Pallansch, Mark; Kew, Olen

2003-01-01

From 1988 to 1993, 30 cases of poliomyelitis associated with poliovirus type 2 were found in seven governorates of Egypt. Because many of the cases were geographically and temporally clustered and because the case isolates differed antigenically from the vaccine strain, it was initially assumed that the cases signaled the continued circulation of wild type 2 poliovirus. However, comparison of sequences encoding the major capsid protein, VP1 (903 nucleotides), revealed that the isolates were related (93 to 97% nucleotide sequence identity) to the Sabin type 2 oral poliovirus vaccine (OPV) strain and unrelated (<82% nucleotide sequence identity) to the wild type 2 polioviruses previously indigenous to Egypt (last known isolate: 1979) or to any contemporary wild type 2 polioviruses found elsewhere. The rate and pattern of VP1 divergence among the circulating vaccine-derived poliovirus (cVDPV) isolates suggested that all lineages were derived from a single OPV infection that occurred around 1983 and that progeny from the initiating infection circulated for approximately a decade within Egypt along several independent chains of transmission. Complete genomic sequences of an early (1988) and a late (1993) cVDPV isolate revealed that their 5′ untranslated region (5′ UTR) and noncapsid- 3′ UTR sequences were derived from other species C enteroviruses. Circulation of type 2 cVDPVs occurred at a time of low OPV coverage in the affected communities and ceased when OPV coverage rates increased. The potential for cVDPVs to circulate in populations with low immunity to poliovirus has important implications for current and future strategies to eradicate polio worldwide. PMID:12857906

Circulation of endemic type 2 vaccine-derived poliovirus in Egypt from 1983 to 1993.

PubMed

Yang, Chen-Fu; Naguib, Tary; Yang, Su-Ju; Nasr, Eman; Jorba, Jaume; Ahmed, Nahed; Campagnoli, Ray; van der Avoort, Harrie; Shimizu, Hiroyuki; Yoneyama, Tetsuo; Miyamura, Tatsuo; Pallansch, Mark; Kew, Olen

2003-08-01

From 1988 to 1993, 30 cases of poliomyelitis associated with poliovirus type 2 were found in seven governorates of Egypt. Because many of the cases were geographically and temporally clustered and because the case isolates differed antigenically from the vaccine strain, it was initially assumed that the cases signaled the continued circulation of wild type 2 poliovirus. However, comparison of sequences encoding the major capsid protein, VP1 (903 nucleotides), revealed that the isolates were related (93 to 97% nucleotide sequence identity) to the Sabin type 2 oral poliovirus vaccine (OPV) strain and unrelated (<82% nucleotide sequence identity) to the wild type 2 polioviruses previously indigenous to Egypt (last known isolate: 1979) or to any contemporary wild type 2 polioviruses found elsewhere. The rate and pattern of VP1 divergence among the circulating vaccine-derived poliovirus (cVDPV) isolates suggested that all lineages were derived from a single OPV infection that occurred around 1983 and that progeny from the initiating infection circulated for approximately a decade within Egypt along several independent chains of transmission. Complete genomic sequences of an early (1988) and a late (1993) cVDPV isolate revealed that their 5' untranslated region (5' UTR) and noncapsid- 3' UTR sequences were derived from other species C enteroviruses. Circulation of type 2 cVDPVs occurred at a time of low OPV coverage in the affected communities and ceased when OPV coverage rates increased. The potential for cVDPVs to circulate in populations with low immunity to poliovirus has important implications for current and future strategies to eradicate polio worldwide.

The Arctic Predictability and Prediction on Seasonal-to-Interannual TimEscales (APPOSITE) project: a summary

NASA Astrophysics Data System (ADS)

Hawkins, Ed; Day, Jonny; Tietsche, Steffen

2016-04-01

Recent years have seen significant developments in seasonal-to-interannual timescale climate prediction capabilities. However, until recently the potential of such systems to predict Arctic climate had not been assessed. We describe a multi-model predictability experiment which was run as part of the Arctic Predictability and Prediction On Seasonal to Inter-annual TimEscales (APPOSITE) project. The main goal of APPOSITE was to quantify the timescales on which Arctic climate is predictable. In order to achieve this, a coordinated set of idealised initial-value predictability experiments, with seven general circulation models, was conducted. This was the first model intercomparison project designed to quantify the predictability of Arctic climate on seasonal to inter-annual timescales. Here we provide a summary and update of the project's results which include: (1) quantifying the predictability of Arctic climate, especially sea ice; (2) the state-dependence of this predictability, finding that extreme years are potentially more predictable than neutral years; (3) analysing a spring 'predictability barrier' to skillful forecasts; (4) initial sea ice thickness information provides much of the skill for summer forecasts; (5) quantifying the sources of error growth and uncertainty in Arctic predictions. The dataset is now publicly available.

Enhanced seasonal forecast skill following stratospheric sudden warmings

NASA Astrophysics Data System (ADS)

Sigmond, M.; Scinocca, J. F.; Kharin, V. V.; Shepherd, T. G.

2013-02-01

Advances in seasonal forecasting have brought widespread socio-economic benefits. However, seasonal forecast skill in the extratropics is relatively modest, prompting the seasonal forecasting community to search for additional sources of predictability. For over a decade it has been suggested that knowledge of the state of the stratosphere can act as a source of enhanced seasonal predictability; long-lived circulation anomalies in the lower stratosphere that follow stratospheric sudden warmings are associated with circulation anomalies in the troposphere that can last up to two months. Here, we show by performing retrospective ensemble model forecasts that such enhanced predictability can be realized in a dynamical seasonal forecast system with a good representation of the stratosphere. When initialized at the onset date of stratospheric sudden warmings, the model forecasts faithfully reproduce the observed mean tropospheric conditions in the months following the stratospheric sudden warmings. Compared with an equivalent set of forecasts that are not initialized during stratospheric sudden warmings, we document enhanced forecast skill for atmospheric circulation patterns, surface temperatures over northern Russia and eastern Canada and North Atlantic precipitation. We suggest that seasonal forecast systems initialized during stratospheric sudden warmings are likely to yield significantly greater forecast skill in some regions.

The impact of endophyte-infected fescue consumption on digital circulation and lameness in the distal thoracic limb of the horse.

PubMed

Douthit, T L; Bormann, J M; Gradert, K C; Lomas, L W; DeWitt, S F; Kouba, J M

2012-09-01

This experiment was conducted to evaluate if consumption of endophyte-infected fescue alters digital circulation in the distal thoracic limb of the horse and to assess if soundness of the hooves of horses is affected by consumption of endophyte-infected fescue. Twelve American Quarter Horses (mean initial BW 459 ± 31 kg), 6 mares and 6 geldings, were used in this 90-d study that comprised high-endophyte (E+) and low-endophyte (E-) treatment groups. Fescue seed was integrated into the E+ diet at a rate sufficient to bring total ergovaline to 200 μg/kg, and endophyte-free fescue seed was incorporated into the E- diet from d 0 to 90. From d 30 to 60, native prairie hay was replaced with high- or low-endophyte fescue hay, bringing total dietary ergovaline to 280 μg/kg (E+) and 18 μg/kg (E-). From d 61 to 90, fescue seed was ground to decrease particle size. On d 0, 30, 60, and 90, Doppler ultrasonography and thermographic imaging were used to measure the diam. of the medial palmar artery, velocity of blood flow, and surface temperature of the hoof as indicators of digital circulation. Lameness examinations were conducted on the same days. There were no consistent treatment differences observed when evaluating measurements of digital circulation. On d 60, horses in the E+ treatment group showed increased hoof sensitivity in the left limb (P = 0.02). These horses tended to have increased hoof sensitivity when both thoracic limbs were averaged (P = 0.06), and they demonstrated increased lameness during longeing (P = 0.08). Data indicated that mares may have increased digital circulation, regardless of treatment, compared with geldings (P ≤ 0.05). Heavier horses also had greater arterial diam., velocity of blood flow, and hoof temperature than lighter BW horses (P ≤ 0.05) on d 30, 60, and 90 at time points that ranged from 90 to 180 min after feeding. Although horses consuming the E+ diet demonstrated increased lameness, especially on d 60, compared with horses consuming the E- diet, the measures of digital circulation did not support the hypothesis that digital circulation was reduced. Because of observed lameness issues, limiting the access of horses to endophyte-infected fescue may be prudent.

Decadal climate prediction (project GCEP).

PubMed

Haines, Keith; Hermanson, Leon; Liu, Chunlei; Putt, Debbie; Sutton, Rowan; Iwi, Alan; Smith, Doug

2009-03-13

Decadal prediction uses climate models forced by changing greenhouse gases, as in the International Panel for Climate Change, but unlike longer range predictions they also require initialization with observations of the current climate. In particular, the upper-ocean heat content and circulation have a critical influence. Decadal prediction is still in its infancy and there is an urgent need to understand the important processes that determine predictability on these timescales. We have taken the first Hadley Centre Decadal Prediction System (DePreSys) and implemented it on several NERC institute compute clusters in order to study a wider range of initial condition impacts on decadal forecasting, eventually including the state of the land and cryosphere. The eScience methods are used to manage submission and output from the many ensemble model runs required to assess predictive skill. Early results suggest initial condition skill may extend for several years, even over land areas, but this depends sensitively on the definition used to measure skill, and alternatives are presented. The Grid for Coupled Ensemble Prediction (GCEP) system will allow the UK academic community to contribute to international experiments being planned to explore decadal climate predictability.

Nutraceutical augmentation of circulating endothelial progenitor cells and hematopoietic stem cells in human subjects.

PubMed

Mikirova, Nina A; Jackson, James A; Hunninghake, Ron; Kenyon, Julian; Chan, Kyle W H; Swindlehurst, Cathy A; Minev, Boris; Patel, Amit N; Murphy, Michael P; Smith, Leonard; Ramos, Famela; Ichim, Thomas E; Riordan, Neil H

2010-04-08

The medical significance of circulating endothelial or hematopoietic progenitors is becoming increasing recognized. While therapeutic augmentation of circulating progenitor cells using G-CSF has resulted in promising preclinical and early clinical data for several degenerative conditions, this approach is limited by cost and inability to perform chronic administration. Stem-Kine is a food supplement that was previously reported to augment circulating EPC in a pilot study. Here we report a trial in 18 healthy volunteers administered Stem-Kine twice daily for a 2 week period. Significant increases in circulating CD133 and CD34 cells were observed at days 1, 2, 7, and 14 subsequent to initiation of administration, which correlated with increased hematopoietic progenitors as detected by the HALO assay. Augmentation of EPC numbers in circulation was detected by KDR-1/CD34 staining and colony forming assays. These data suggest Stem-Kine supplementation may be useful as a stimulator of reparative processes associated with mobilization of hematopoietic and endothelial progenitors.

Broadening Participation in Geosciences with Academic Year and Summer Research Experiences

NASA Astrophysics Data System (ADS)

Austin, S. A.; Howard, A.; Johnson, L. P.; Gutierrez, R.; Chow, Y.

2013-12-01

Medgar Evers College, City University of New York, has initiated a multi-tiered strategy aimed at increasing the number of under-represented minority and female students pursuing careers in the Geosciences, especially Earth and Atmospheric Sciences and related areas. The strategy incorporates research on the persistence of minority and female under-represented students in STEM disciplines. The initiatives include NASA and NSF-funded team-based undergraduate research activities during the summer and academic year as well as academic support (clustering, PTLT workshops for gatekeeper courses), curriculum integration modules, and independent study/special topics courses. In addition, high school students are integrated into summer research activities working with undergraduate and graduate students as well as faculty and other scientist mentors. An important initial component was the building of an infrastructure to support remote sensing, supported by NASA. A range of academic year and summer research experiences are provided to capture student interest in the geosciences. NYC-based research activities include urban impacts of global climate change, the urban heat island, ocean turbulence and general circulation models, and space weather: magnetic rope structure, solar flares and CMEs. Field-based investigations include atmospheric observations using BalloonSat sounding vehicles, observations of tropospheric ozone using ozonesondes, and investigations of the ionosphere using a CubeSat. This presentation provides a description of the programs, student impact, challenges and observations.

Analysis and numerical study of inertia-gravity waves generated by convection in the tropics

NASA Astrophysics Data System (ADS)

Evan, Stephanie

2011-12-01

Gravity waves transport momentum and energy upward from the troposphere and by dissipation affect the large-scale structure of the middle atmosphere. An accurate representation of these waves in climate models is important for climate studies, but is still a challenge for most global and climate models. In the tropics, several studies have shown that mesoscale gravity waves and intermediate scale inertia-gravity waves play an important role in the dynamics of the upper atmosphere. Despite observational evidence for the importance of forcing of the tropical circulation by inertia-gravity waves, their exact properties and forcing of the tropical stratospheric circulation are not fully understood. In this thesis, properties of tropical inertia-gravity waves are investigated using radiosonde data from the 2006 Tropical Warm Pool International Cloud Experiment (TWP-ICE), the European Centre for Medium-Range Weather Forecasts (ECMWF) dataset and high-resolution numerical experiments. Few studies have characterized inertia-gravity wave properties using radiosonde profiles collected on a campaign basis. We first examine the properties of intermediate-scale inertia-gravity waves observed during the 2006 TWP-ICE campaign in Australia. We show that the total vertical flux of horizontal momentum associated with the waves is of the same order of magnitude as previous observations of Kelvin waves. This constitutes evidence for the importance of the forcing of the tropical circulation by intermediate-scale inertia-gravity waves. Then, we focus on the representation of inertia-gravity waves in analysis data. The wave event observed during TWP-ICE is also present in the ECMWF data. A comparison between the characteristics of the inertia-gravity wave derived with the ECMWF data to the properties of the wave derived with the radiosonde data shows that the ECMWF data capture similar structure for this wave event but with a larger vertical wavelength. The Weather Research and Forecasting (WRF) modeling system is used to understand the representation of the wave event in the ECMWF data. The model is configured as a tropical channel with a high top at 1 hPa. WRF is used with the same horizontal resolution (˜ 40 km) as the operational ECMWF in 2006 while using a finer vertical grid-spacing than ECMWF. Different experiments are performed to determine the sensitivity of the wave structure to cumulus schemes, initial conditions and vertical resolution. We demonstrate that high vertical resolution would be required for ECMWF to accurately resolve the vertical structure of inertia-gravity waves and their effect on the middle atmosphere circulation. Lastly we perform WRF simulations in January 2006 and 2007 to assess gravity wave forcing of the tropical stratospheric circulation. In these simulations a large part of the gravity wave spectrum is explicitly simulated. The WRF model is able to reproduce the evolution of the mean tropical stratospheric zonal wind when compared to observational data and the ECMWF reanalysis. It is shown that gravity waves account for 60% up to 80% of the total wave forcing of the tropical stratospheric circulation. We also compute wave forcing associated with intermediate-scale inertiagravity waves. In the WRF simulations this wave type represents ˜ 30% of the total gravity wave forcing. This suggests that intermediate-scale inertia-gravity waves can play an important role in the tropical middle-atmospheric circulation. In addition, the WRF high-resolution simulations are used to provide some guidance for constraining gravity wave parameterizations in coarse-grid climate models.

Multimodel Evidence for an Atmospheric Circulation Response to Arctic Sea Ice Loss in the CMIP5 Future Projections

NASA Astrophysics Data System (ADS)

Zappa, G.; Pithan, F.; Shepherd, T. G.

2018-01-01

Previous single-model experiments have found that Arctic sea ice loss can influence the atmospheric circulation. To evaluate this process in a multimodel ensemble, a novel methodology is here presented and applied to infer the influence of Arctic sea ice loss in the CMIP5 future projections. Sea ice influence is estimated by comparing the circulation response in the RCP8.5 scenario against the circulation response to sea surface warming and CO2 increase inferred from the AMIPFuture and AMIP4xCO2 experiments, where sea ice is unperturbed. Multimodel evidence of the impact of sea ice loss on midlatitude atmospheric circulation is identified in late winter (January-March), when the sea ice-related surface heat flux perturbation is largest. Sea ice loss acts to suppress the projected poleward shift of the North Atlantic jet, to increase surface pressure in northern Siberia, and to lower it in North America. These features are consistent with previous single-model studies, and the present results indicate that they are robust to model formulation.

Multimodel Evidence for an Atmospheric Circulation Response to Arctic Sea Ice Loss in the CMIP5 Future Projections.

PubMed

Zappa, G; Pithan, F; Shepherd, T G

2018-01-28

Previous single-model experiments have found that Arctic sea ice loss can influence the atmospheric circulation. To evaluate this process in a multimodel ensemble, a novel methodology is here presented and applied to infer the influence of Arctic sea ice loss in the CMIP5 future projections. Sea ice influence is estimated by comparing the circulation response in the RCP8.5 scenario against the circulation response to sea surface warming and CO 2 increase inferred from the AMIPFuture and AMIP4xCO2 experiments, where sea ice is unperturbed. Multimodel evidence of the impact of sea ice loss on midlatitude atmospheric circulation is identified in late winter (January-March), when the sea ice-related surface heat flux perturbation is largest. Sea ice loss acts to suppress the projected poleward shift of the North Atlantic jet, to increase surface pressure in northern Siberia, and to lower it in North America. These features are consistent with previous single-model studies, and the present results indicate that they are robust to model formulation.

Theoretical and experimental design studies for the Atmospheric General Circulation Experiment

NASA Technical Reports Server (NTRS)

Fowlis, W. W.; Hathaway, D. H.; Miller, T. L.; Roberts, G. O.; Kopecky, K. J.

1985-01-01

The major criterion for the Atmospheric General Circulation Experiment (AGCE) design is that it be possible to realize strong baroclinic instability in the spherical configuration chosen. A configuration was selected in which a hemispherical shell of fluid is subjected to latitudinal temperature gradients on its spherical boundaries and the latitudinal boundaries are insulators. Work in the laboratory with a cylindrical version of this configuration revealed more instabilities than baroclinic instability. Since researchers fully expect these additional instabilities to appear in the spherical configuration also, they decided to continue the laboratory cylindrical annulus studies. Four flow regimes were identified: an axisymmetric Hadley circulation, boundary layer convection, baroclinic waves and deep thermal convection. Regime diagrams were prepared.

Crucial considerations for pipelines to validate circulating biomarkers for breast cancer.

PubMed

Ewaisha, Radwa; Gawryletz, Chelsea D; Anderson, Karen S

2016-01-01

Despite decades of progress in breast imaging, breast cancer remains the second most common cause of cancer mortality in women. The rapidly proliferative breast cancers that are associated with high relapse rates and mortality frequently present in younger women, in unscreened individuals, or in the intervals between screening mammography. Biomarkers exist for monitoring metastatic disease, such as CEA, CA27.29 and CA15-3, but there are no circulating biomarkers clinically available for early detection, prognosis, or monitoring for clinical relapse. There has been significant progress in the discovery of potential circulating biomarkers, including proteins, autoantibodies, nucleic acids, exosomes, and circulating tumor cells, but the vast majority of these biomarkers have not progressed beyond initial research discovery, and none have yet been approved for clinical use in early stage disease. Here, the authors review the crucial considerations of developing pipelines for the rapid evaluation of circulating biomarkers for breast cancer.

A new dynamical downscaling approach with GCM bias corrections and spectral nudging

NASA Astrophysics Data System (ADS)

Xu, Zhongfeng; Yang, Zong-Liang

2015-04-01

To improve confidence in regional projections of future climate, a new dynamical downscaling (NDD) approach with both general circulation model (GCM) bias corrections and spectral nudging is developed and assessed over North America. GCM biases are corrected by adjusting GCM climatological means and variances based on reanalysis data before the GCM output is used to drive a regional climate model (RCM). Spectral nudging is also applied to constrain RCM-based biases. Three sets of RCM experiments are integrated over a 31 year period. In the first set of experiments, the model configurations are identical except that the initial and lateral boundary conditions are derived from either the original GCM output, the bias-corrected GCM output, or the reanalysis data. The second set of experiments is the same as the first set except spectral nudging is applied. The third set of experiments includes two sensitivity runs with both GCM bias corrections and nudging where the nudging strength is progressively reduced. All RCM simulations are assessed against North American Regional Reanalysis. The results show that NDD significantly improves the downscaled mean climate and climate variability relative to other GCM-driven RCM downscaling approach in terms of climatological mean air temperature, geopotential height, wind vectors, and surface air temperature variability. In the NDD approach, spectral nudging introduces the effects of GCM bias corrections throughout the RCM domain rather than just limiting them to the initial and lateral boundary conditions, thereby minimizing climate drifts resulting from both the GCM and RCM biases.

Exploring Nurse Communication About Spirituality.

PubMed

Wittenberg, Elaine; Ragan, Sandra L; Ferrell, Betty

2017-07-01

Although spiritual care is considered one of the pillars of palliative care, many health-care providers never receive formal training on how to communicate about spirituality with patients and families. The aim of this study was to explore the spiritual care experiences of oncology nurses in order to learn more about patient needs and nurse responses. A survey was circulated at a communication training course for oncology nurses in June 2015. Nurses recalled a care experience that included the initiation of a spiritual care topic and their response to the patient/family. Data were analyzed using thematic analysis. Nurses reported that communication about spirituality was primarily initiated by patients, rather than family members, and spiritual topics commonly emerged during the end of life or when patients experienced spiritual distress. Nurses' experiences highlighted the positive impact spiritual conversations had on the quality of patient care and its benefit to families. Spiritual communication was described as an important nursing role at the end of patients' lives, and nonverbal communication, listening, and discussing patients' emotions were emphasized as important and effective nurse communication skills during spiritual care conversations. Approximately one-third of nurses in the sample reported sharing their own personal spiritual or religious backgrounds with patients, and they reported that these sharing experiences strengthened their own faith. It is evident that patients want to discuss spiritual topics during care. Study findings illustrate the need to develop a spiritual communication curriculum and provide spiritual care communication training to clinicians.

Walker circulation in a transient climate

NASA Astrophysics Data System (ADS)

Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

2016-04-01

The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate response (temperature change by the time of CO2 doubling), which in turn might be related to a decreased ocean heat uptake. This uncertainty across the models we attribute to the multitude of factors controlling ocean and atmosphere heat exchange, both at global and regional scales, as well as to the present capabilities of GCMs in simulating this exchange. References: England, M. H., McGregor, S., Spence, P., Meehl, G. A., Timmermann, A., Cai, W., Gupta, A. S., McPhaden, M. J., Purich, A., and Santoso, A., 2014. Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus. Nature Climate Change 4 (3): 222-227. Ma, J., and Xie, S. P., 2013. Regional Patterns of Sea Surface Temperature Change: A Source of Uncertainty in Future Projections of Precipitation and Atmospheric Circulation*. Journal of Climate, 26 (8): 2482-2501

Interannual Variation of Surface Circulation in the Japan/East Sea due to External Forcings and Intrinsic Variability

NASA Astrophysics Data System (ADS)

Choi, Byoung-Ju; Cho, Seong Hun; Jung, Hee Seok; Lee, Sang-Ho; Byun, Do-Seong; Kwon, Kyungman

2018-03-01

The interannual variation of surface ocean currents can be as large as seasonal variation in the Japan/East Sea (JES). To identify the major factors that cause such interannual variability of surface ocean circulation in the JES, surface circulation was simulated from 1998 to 2009 using a three-dimensional model. Contributions of atmospheric forcing (ATM), open boundary data (OBC), and intrinsic variability (ITV) of the surface flow in the JES on the interannual variability of surface ocean circulation were separately examined using numerical simulations. Variability in surface circulation was quantified in terms of variance in sea surface height, 100-m depth water temperature, and surface currents. ITV was found to be the dominant factor that induced interannual variabilities of surface circulation, the main path of the East Korea Warm Current (EKWC), and surface kinetic energy on a time scale of 2-4 years. OBC and ATM were secondary factors contributing to the interannual variation of surface circulation. Interannual variation of ATM changed the separation latitude of EKWC and increased the variability of surface circulation in the Ulleung Basin. Interannual variation of OBC enhanced low-frequency changes in surface circulation and eddies in the Yamato Basin. It also modulated basin-wide uniform oscillations of sea level. This study suggests that precise estimation of initial conditions using data assimilation is essential for long-term prediction of surface circulation in the JES.

Modeling of circulating fluised beds for post-combustion carbon capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, A.; Shadle, L.; Miller, D.

2011-01-01

A compartment based model for a circulating fluidized bed reactor has been developed based on experimental observations of riser hydrodynamics. The model uses a cluster based approach to describe the two-phase behavior of circulating fluidized beds. Fundamental mass balance equations have been derived to describe the movement of both gas and solids though the system. Additional work is being performed to develop the correlations required to describe the hydrodynamics of the system. Initial testing of the model with experimental data shows promising results and highlights the importance of including end effects within the model.

Effect of Glucocorticoid-Induced Insulin Resistance on Follicle Development and Ovulation1

PubMed Central

Hackbart, Katherine S.; Cunha, Pauline M.; Meyer, Rudelle K.; Wiltbank, Milo C.

2013-01-01

ABSTRACT Polycystic ovarian syndrome (PCOS) is characterized by hyperandrogenemia, polycystic ovaries, and menstrual disturbance and a clear association with insulin resistance. This research evaluated whether induction of insulin resistance, using dexamethasone (DEX), in a monovular animal model, the cow, could produce an ovarian phenotype similar to PCOS. In all of these experiments, DEX induced insulin resistance in cows as shown by increased glucose, insulin, and HOMA-IR (homeostasis model assessment of insulin resistance). Experiment 1: DEX induced anovulation (zero of five DEX vs. four of four control cows ovulated) and decreased circulating estradiol (E2). Experiment 2: Gonadotropin-releasing hormone (GnRH) was administered to determine pituitary and follicular responses during insulin resistance. GnRH induced a luteinizing hormone (LH) surge and ovulation in both DEX (seven of seven) and control (seven of seven) cows. Experiment 3: E2 was administered to determine hypothalamic responsiveness after induction of an E2 surge in DEX (eight of eight) and control (eight of eight) cows. An LH surge was induced in control (eight of eight) but not DEX (zero of eight) cows. All control (eight of eight) but only two of eight DEX cows ovulated within 60 h of E2 administration. Experiment 4: Short-term DEX was initiated 24 h after induced luteal regression to determine if DEX could acutely block ovulation before peak insulin resistance was induced, similar to progesterone (P4). All control (five of five), no P4-treated (zero of six), and 50% of DEX-treated (three of six) cows ovulated by 96 h after luteal regression. All anovular cows had reduced circulating E2. These data are consistent with DEX creating a lesion in hypothalamic positive feedback to E2 without altering pituitary responsiveness to GnRH or ovulatory responsiveness of follicles to LH. It remains to be determined if the considerable insulin resistance and the reduced follicular E2 production induced by DEX had any physiological importance in the induction of anovulation. PMID:23616591

Experimentally determined rock-fluid interactions applicable to a natural hot dry rock geothermal system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charles, R.W.; Holley, C.E. Jr.; Tester, J.W.

1980-02-01

The Los Alamos Scientific Laboratory is pursuing laboratory and field experiments in the development of the Hot Dry Rock concept of geothermal energy. The field program consists of experiments in a hydraulically fractured region of low permeability in which hot rock is intercepted by two wellbores. These experiments are designed to test reservoir engineering parameters such as: heat extraction rates, water loss rates, flow characteristics including impedance and buoyancy, seismic activity and fluid chemistry. Laboratory experiments have been designed to provide information on the mineral reactivity which may be encountered in the field program. Two experimental circulation systems have beenmore » built to study the rates of dissolution and alteration in dynamic flow. Solubility studies have been done in agitated systems. To date, pure minerals, samples of the granodiorite from the actual reservoir and Tijeras Canyon granite have been reacted with distilled water and various solutions of NaCl, NaOH, and Na/sub 2/CO/sub 3/. The results of these experimental systems are compared to observations made in field experiments done in a hot dry rock reservoir at a depth of approximately 3 km with initial rock temperatures of 150 to 200/sup 0/C.« less

Osteolytic bone lesions, severe hypercalcemia without circulating blasts: unusual presentation of childhood acute lymphoblastic leukemia

PubMed Central

Bechir, Achour; Haifa, Regaieg; Atef, Ben Abdelkader; Emna, Bouslema; Asma, Achour; Nesrine, Ben Sayed; Yosra, Ben Youssef; Abdrrahim, Khelif

2017-01-01

Hypercalcemia and severe osteolytic lesions are rare complications of acute lymphoblastic leukemia (ALL) in childhood. We report a case of a 3 years old boy who presented with prolonged fever, nausea, vomiting and increasing lower limbs pain. Skeletal X-rays and CT scan showed severe osteolytic lesions of the skull and extremities. Her physical examination showed multiple cervical lymph nodes. In laboratory tests, he had severe hypercalcemia. Parathyroid hormone (PTH) was not elevated. Despite the absence of circulating blasts, bone marrow biopsy revealed B-precursor (ALL). Hypercalcemia was initially treated with intravenous isotonic sodium chloride solution and diuretics but the serum calcium level normalized only after the beginning of corticosteroids and chemotherapy. The child responded initially to chemotherapy and eventually relapsed and died of septic shock. Acute leukemia must be considered in differential diagnosis in patients with hypercalcemia. A detailed examination even when there no circulating blasts in their peripheral blood smear, and if in doubt bone marrow aspiration should must be taken into consideration. PMID:28690758

Prolonged effect of the stratospheric pathway in linking Barents-Kara Sea sea ice variability to the midlatitude circulation in a simplified model

NASA Astrophysics Data System (ADS)

Zhang, Pengfei; Wu, Yutian; Smith, Karen L.

2018-01-01

To better understand the dynamical mechanism that accounts for the observed lead-lag correlation between the early winter Barents-Kara Sea (BKS) sea ice variability and the later winter midlatitude circulation response, a series of experiments are conducted using a simplified atmospheric general circulation model with a prescribed idealized near-surface heating over the BKS. A prolonged effect is found in the idealized experiments following the near-surface heating and can be explicitly attributed to the stratospheric pathway and the long time scale in the stratosphere. The analysis of the Eliassen-Palm flux shows that, as a result of the imposed heating and linear constructive interference, anomalous upward propagating planetary-scale waves are excited and weaken the stratospheric polar vortex. This stratospheric response persists for approximately 1-2 months accompanied by downward migration to the troposphere and the surface. This downward migration largely amplifies and extends the low-level jet deceleration in the midlatitudes and cold air advection over central Asia. The idealized model experiments also suggest that the BKS region is the most effective in affecting the midlatitude circulation than other regions over the Arctic.

World Ocean Circulation Experiment

NASA Technical Reports Server (NTRS)

Clarke, R. Allyn

1992-01-01

The oceans are an equal partner with the atmosphere in the global climate system. The World Ocean Circulation Experiment is presently being implemented to improve ocean models that are useful for climate prediction both by encouraging more model development but more importantly by providing quality data sets that can be used to force or to validate such models. WOCE is the first oceanographic experiment that plans to generate and to use multiparameter global ocean data sets. In order for WOCE to succeed, oceanographers must establish and learn to use more effective methods of assembling, quality controlling, manipulating and distributing oceanographic data.

Experimental Study and CFD Simulation of a 2D Circulating Fluidized Bed

NASA Astrophysics Data System (ADS)

Kallio, S.; Guldén, M.; Hermanson, A.

Computational fluid dynamics (CFD) gains popularity in fluidized bed modeling. For model validation, there is a need of detailed measurements under well-defined conditions. In the present study, experiments were carried out in a 40 em wide and 3 m high 2D circulating fluidized bed. Two experiments were simulated by means of the Eulerian multiphase models of the Fluent CFD software. The vertical pressure and solids volume fraction profiles and the solids circulation rate obtained from the simulation were compared to the experimental results. In addition, lateral volume fraction profiles could be compared. The simulated CFB flow patterns and the profiles obtained from simulations were in general in a good agreement with the experimental results.

SASSYS pretest analysis of the THORS-SHRS experiments. [LMFBR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bordner, G.L.; Dunn, F.E.

The THORS Facility at ORNL was recently modified to allow the testing of two parallel 19-pin simulated fueled subassemblies under natural circulation conditions similar to those that might occur during a partial failure of the shutdown heat removal system (SHRS) of a liquid-metal fast breeder reactor. The planned experimental program included a series of tests at various inlet plenum temperatures to determine boiling threshold power levels and the power range for stable boiling during natural circulation operation. Pretest calculations were performed at ANL, which supplement those carried out at ORNL for the purposes of validating the SASSYS model in themore » natural circulation regime and of providing data which would be useful in planning the experiments.« less

Oceanographic and atmospheric conditions on the continental shelf north of the Monterey Bay during August 2006

NASA Astrophysics Data System (ADS)

Ramp, Steven R.; Lermusiaux, Pierre F. J.; Shulman, Igor; Chao, Yi; Wolf, Rebecca E.; Bahr, Frederick L.

2011-09-01

A comprehensive data set from the ocean and atmosphere was obtained just north of the Monterey Bay as part of the Monterey Bay 2006 (MB06) field experiment. The wind stress, heat fluxes, and sea surface temperature were sampled by the Naval Postgraduate School's TWIN OTTER research aircraft. In situ data were collected using ships, moorings, gliders and AUVs. Four data-assimilating numerical models were additionally run, including the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS ®) model for the atmosphere and the Harvard Ocean Prediction System (HOPS), the Regional Ocean Modeling System (ROMS), and the Navy Coastal Ocean Model (NCOM) for the ocean. The scientific focus of the Adaptive Sampling and Prediction Experiment (ASAP) was on the upwelling/relaxation cycle and the resulting three-dimensional coastal circulation near a coastal promontory, in this case Point Año Nuevo, CA. The emphasis of this study is on the circulation over the continental shelf as estimated from the wind forcing, two ADCP moorings, and model outputs. The wind stress during August 2006 consisted of 3-10 day upwelling favorable events separated by brief 1-3 day relaxations. During the first two weeks there was some correlation between local winds and currents and the three models' capability to reproduce the events. During the last two weeks, largely equatorward surface wind stress forced the sea surface and barotropic poleward flow occurred over the shelf, reducing model skill at predicting the circulation. The poleward flow was apparently remotely forced by mesoscale eddies and alongshore pressure gradients, which were not well simulated by the models. The small, high-resolution model domains were highly reliant on correct open boundary conditions to drive these larger-scale poleward flows. Multiply-nested models were no more effective than well-initialized local models in this respect.

The subpolar North Atlantic - Response to North Atlantic oscillation like forcing and Influence on the Atlantic meridional overturning circulation

NASA Astrophysics Data System (ADS)

Lohmann, Katja; Drange, Helge; Jungclaus, Johann

2010-05-01

The extent and strength of the North Atlantic subpolar gyre (SPG) changed rapidly in the mid-1990s, going from large and strong in 1995 to substantially weakened in the following years. The abrupt change in the intensity of the SPG is commonly linked to the reversal of the North Atlantic Oscillation (NAO) index, changing from strong positive to negative values, in the winter 1995/96. In this study we investigate the impact of the initial SPG state on its subsequent behavior by means of an ocean general circulation model driven by NCEP-NCAR reanalysis fields. Our sensitivity integrations suggest that the weakening of the SPG cannot be explained by the change in the atmospheric forcing alone. Rather, for the time period around 1995, the SPG was about to weaken, irrespective of the actual atmospheric forcing, due to the ocean state governed by the persistently strong positive NAO during the preceding seven years (1989 to 1995). Our analysis indicates that it was this preconditioning of the ocean, in combination with the sudden drop in the NAO in 1995/96, that lead to the strong and rapid weakening of the SPG in the second half of the 1990s. In the second part, the sensitivity of the low-frequency variability of the Atlantic meridional overturning circulation to changes in the subpolar North Atlantic is investigated using a 2000 year long control integration as well as sensitivity experiments with the MPI-M Earth System Model. Two 1000 year long sensitivity experiments will be performed, in which the low-frequency variability in the overflow transports from the Nordic Seas and in the subpolar deep water formation rates is suppressed respectively. This is achieved by nudging temperature and salinity in the GIN Sea or in the subpolar North Atlantic (up to about 1500m depth) towards a monthly climatology obtained from the last 1000 years of the control integration.

Initial Circulation and Peak Vorticity Behavior of Vortices Shed from Airfoil Vortex Generators

NASA Technical Reports Server (NTRS)

Wendt, Bruce J.; Biesiadny, Tom (Technical Monitor)

2001-01-01

An extensive parametric study of vortices shed from airfoil vortex generators has been conducted to determine the dependence of initial vortex circulation and peak vorticity on elements of the airfoil geometry and impinging flow conditions. These elements include the airfoil angle of attack, chord length, span, aspect ratio, local boundary layer thickness, and free stream Mach number. In addition, the influence of airfoil-to-airfoil spacing on the circulation and peak vorticity has been examined for pairs of co-rotating and counter-rotating vortices. The vortex generators were symmetric airfoils having a NACA-0012 cross-sectional profile. These airfoils were mounted either in isolation, or in pairs, on the surface of a straight pipe. The turbulent boundary layer thickness to pipe radius ratio was about 17 percent. The circulation and peak vorticity data were derived from cross-plane velocity measurements acquired with a seven-hole probe at one chord-length downstream of the airfoil trailing edge location. The circulation is observed to be proportional to the free-stream Mach number, the angle-of-attack, and the span-to-boundary layer thickness ratio. With these parameters held constant, the circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio. The peak vorticity is also observed to be proportional to the free-stream Mach number, the airfoil angle-of-attack, and the span-to-boundary layer thickness ratio. Unlike circulation, however, the peak vorticity is observed to increase with increasing aspect ratio, reaching a peak value at an aspect ratio of about 2.0 before falling off again at higher values of aspect ratio. Co-rotating vortices shed from closely spaced pairs of airfoils have values of circulation and peak vorticity under those values found for vortices shed from isolated airfoils of the same geometry. Conversely, counter-rotating vortices show enhanced values of circulation and peak vorticity when compared to values obtained in isolation. The circulation may be accurately modeled with an expression based on Prandtl's relationship between finite airfoil circulation and airfoil geometry. A correlation for the peak vorticity has been derived from a conservation relationship equating the moment at the airfoil tip to the rate of angular momentum production of the shed vortex, modeled as a Lamb (ideal viscous) vortex. This technique provides excellent qualitative agreement to the observed behavior of peak vorticity for low aspect ratio airfoils typically used as vortex generators.

Return of spontaneous Circulation Is Not Affected by Different Chest Compression Rates Superimposed with Sustained Inflations during Cardiopulmonary Resuscitation in Newborn Piglets

PubMed Central

Li, Elliott S.; Cheung, Po-Yin; Lee, Tze-Fun; Lu, Min; O'Reilly, Megan

2016-01-01

Objective Recently, sustained inflations (SI) during chest compression (CC) have been suggested as an alternative to the current approach during neonatal resuscitation. However, the optimal rate of CC during SI has not yet been established. Our aim was to determine whether different CC rates during SI reduce time to return of spontaneous circulation (ROSC) and improve hemodynamic recovery in newborn piglets with asphyxia-induced bradycardia. Intervention and measurements Term newborn piglets were anesthetized, intubated, instrumented and exposed to 45-min normocapnic hypoxia followed by asphyxia. Resuscitation was initiated when heart rate decreased to 25% of baseline. Piglets were randomized into three groups: CC superimposed by SI at a rate of 90 CC per minute (SI+CC 90, n = 8), CC superimposed by SI at a rate of 120 CC per minute (SI+CC 120, n = 8), or a sham group (n = 6). Cardiac function, carotid blood flow, cerebral oxygenation and respiratory parameters were continuously recorded throughout the experiment. Main results Both treatment groups had similar time of ROSC, survival rates, hemodynamic and respiratory parameters during cardiopulmonary resuscitation. The hemodynamic recovery in the subsequent 4h was similar in both groups and was only slightly lower than sham-operated piglets at the end of experiment. Conclusion Newborn piglets resuscitated by SI+CC 120 did not show a significant advantage in ROSC, survival, and hemodynamic recovery as compared to those piglets resuscitated by SI+CC 90. PMID:27304210

Electrostatic Potential Generated During Extracorporeal Pump Prime Circulation Before Cardiopulmonary Bypass Initiation

PubMed Central

Newton, Haley S.; Niles, Scott D.; Ploessl, James; Richenbacher, Wayne

2007-01-01

Abstract: The development of electrostatic potentials generated during cardiopulmonary bypass (CPB) procedures using polyvinylchloride (PVC) tubing in conjunction with roller pumps has been previously documented. The resulting damage from the electrostatic discharge (ESD) has been reported to affect gas transfer devices, but details of potential damage to electronic components commonly used during extracorporeal circulation have not been similarly described. The purpose of this study was to measure the ability of a triboelectric potential to be generated from a primed, circulating, adult CPB pump before the initiation of CPB. Two identical adult CPB circuits were assembled: one incorporating a roller pump and the second incorporating a centrifugal pump mechanism. Primed pumps were circulated (1–6 LPM), and evidence of generated triboelectric potentials was evaluated using a digital multimeter (Fluke 8062 A). The ESD generated from an adult CPB circuit using a roller head configuration elicited a charge in excess of 600 DC V. An identical circuit constructed with a centrifugal pump mechanism did not produce any measurable charge. Sensitive electrical components in the CPB hardware platform may be damaged by ESD potential spikes of this magnitude. Preventative measures, such as circuit charge dissipation, may reduce the potential for such damage when using PVC tubing. PMID:17486872

Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) scientific advances and future west pacific coordination

NASA Astrophysics Data System (ADS)

Ganachaud, A. S.; Sprintall, J.; Lin, X.; Ando, K.

2016-02-01

The Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) is an international research program under the auspices of CLIVAR (Climate Variability and Predictability). The key objectives are to understand the Southwest Pacific Ocean circulation and Convergence Zone (SPCZ) dynamics, as well as their influence on regional and basin-scale climate patterns. It was designed to measure and monitor the ocean circulation, and to validate and improve numerical models. South Pacific oceanic waters are carried from the subtropical gyre centre in the westward flowing South Equatorial Current (SEC), towards the southwest Pacific-a major circulation pathway that redistributes water from the subtropics to the equator and Southern Ocean. Water transit through the Coral and Solomon Seas is potentially of great importance to tropical climate prediction because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate ENSO and produce basin-scale climate feedbacks. On average, the oceanic circulation is driven by the Trade Winds, and subject to substantial variability, related with the SPCZ position and intensity. The circulation is complex, with the SEC splitting into zonal jets upon encountering island archipelagos, before joining either the East Australian Current or the New Guinea Costal UnderCurrent towards the equator. SPICE included large, coordinated in situ measurement programs and high resolution numerical simulations of the area. After 8 years of substantial in situ oceanic observational and modeling efforts, our understanding of the region has much improved. We have a refined description of the SPCZ behavior, boundary currents, pathways, and water mass transformation, including the previously undocumented Solomon Sea. The transports are large and vary substantially in a counter-intuitive way, with asymmetries and gating effects that depend on time scales. We will review the recent advancements and discuss our current knowledge gaps and important emerging research directions. In particular we will discuss how SPICE, along with the Northwestern Pacific Ocean Circulation and Climate Experiment (NPOCE) and Indonesian ThroughFlow (ITF) programs could evolve toward an integrative observing system under CLIVAR coordination.

Buoyancy Driven Coolant Mixing Studies of Natural Circulation Flows at the ROCOM Test Facility Using ANSYS CFX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hohne, Thomas; Kliem, Soren; Rohde, Ulrich

2006-07-01

Coolant mixing in the cold leg, downcomer and the lower plenum of pressurized water reactors is an important phenomenon mitigating the reactivity insertion into the core. Therefore, mixing of the de-borated slugs with the ambient coolant in the reactor pressure vessel was investigated at the four loop 1:5 scaled ROCOM mixing test facility. Thermal hydraulics analyses showed, that weakly borated condensate can accumulate in particular in the pump loop seal of those loops, which do not receive safety injection. After refilling of the primary circuit, natural circulation in the stagnant loops can re-establish simultaneously and the de-borated slugs are shiftedmore » towards the reactor pressure vessel (RPV). In the ROCOM experiments, the length of the flow ramp and the initial density difference between the slugs and the ambient coolant was varied. From the test matrix experiments with 0 resp. 2% density difference between the de-borated slugs and the ambient coolant were used to validate the CFD software ANSYS CFX. To model the effects of turbulence on the mean flow a higher order Reynolds stress turbulence model was employed and a mesh consisting of 6.4 million hybrid elements was utilized. Only the experiments and CFD calculations with modeled density differences show a stratification in the downcomer. Depending on the degree of density differences the less dense slugs flow around the core barrel at the top of the downcomer. At the opposite side the lower borated coolant is entrained by the colder safety injection water and transported to the core. The validation proves that ANSYS CFX is able to simulate appropriately the flow field and mixing effects of coolant with different densities. (authors)« less

Insulin does not stimulate muscle protein synthesis during increased plasma branched-chain amino acids alone but still decreases whole body proteolysis in humans.

PubMed

Everman, Sarah; Meyer, Christian; Tran, Lee; Hoffman, Nyssa; Carroll, Chad C; Dedmon, William L; Katsanos, Christos S

2016-10-01

Insulin stimulates muscle protein synthesis when the levels of total amino acids, or at least the essential amino acids, are at or above their postabsorptive concentrations. Among the essential amino acids, branched-chain amino acids (BCAA) have the primary role in stimulating muscle protein synthesis and are commonly sought alone to stimulate muscle protein synthesis in humans. Fourteen healthy young subjects were studied before and after insulin infusion to examine whether insulin stimulates muscle protein synthesis in relation to the availability of BCAA alone. One half of the subjects were studied in the presence of postabsorptive BCAA concentrations (control) and the other half in the presence of increased plasma BCAA (BCAA). Compared with that prior to the initiation of the insulin infusion, fractional synthesis rate of muscle protein (%/h) did not change (P > 0.05) during insulin in either the control (0.04 ± 0.01 vs 0.05 ± 0.01) or the BCAA (0.05 ± 0.02 vs. 0.05 ± 0.01) experiments. Insulin decreased (P < 0.01) whole body phenylalanine rate of appearance (μmol·kg -1 ·min -1 ), indicating suppression of muscle proteolysis, in both the control (1.02 ± 0.04 vs 0.76 ± 0.04) and the BCAA (0.89 ± 0.07 vs 0.61 ± 0.03) experiments, but the change was not different between the two experiments (P > 0.05). In conclusion, insulin does not stimulate muscle protein synthesis in the presence of increased circulating levels of plasma BCAA alone. Insulin's suppressive effect on proteolysis is observed independently of the levels of circulating plasma BCAA. Copyright © 2016 the American Physiological Society.

Insulin does not stimulate muscle protein synthesis during increased plasma branched-chain amino acids alone but still decreases whole body proteolysis in humans

PubMed Central

Everman, Sarah; Meyer, Christian; Tran, Lee; Hoffman, Nyssa; Carroll, Chad C.; Dedmon, William L.

2016-01-01

Insulin stimulates muscle protein synthesis when the levels of total amino acids, or at least the essential amino acids, are at or above their postabsorptive concentrations. Among the essential amino acids, branched-chain amino acids (BCAA) have the primary role in stimulating muscle protein synthesis and are commonly sought alone to stimulate muscle protein synthesis in humans. Fourteen healthy young subjects were studied before and after insulin infusion to examine whether insulin stimulates muscle protein synthesis in relation to the availability of BCAA alone. One half of the subjects were studied in the presence of postabsorptive BCAA concentrations (control) and the other half in the presence of increased plasma BCAA (BCAA). Compared with that prior to the initiation of the insulin infusion, fractional synthesis rate of muscle protein (%/h) did not change (P > 0.05) during insulin in either the control (0.04 ± 0.01 vs 0.05 ± 0.01) or the BCAA (0.05 ± 0.02 vs. 0.05 ± 0.01) experiments. Insulin decreased (P < 0.01) whole body phenylalanine rate of appearance (μmol·kg−1·min−1), indicating suppression of muscle proteolysis, in both the control (1.02 ± 0.04 vs 0.76 ± 0.04) and the BCAA (0.89 ± 0.07 vs 0.61 ± 0.03) experiments, but the change was not different between the two experiments (P > 0.05). In conclusion, insulin does not stimulate muscle protein synthesis in the presence of increased circulating levels of plasma BCAA alone. Insulin's suppressive effect on proteolysis is observed independently of the levels of circulating plasma BCAA. PMID:27530230

KSC-03PD-0180

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- The Pegasus XL rocket is dropped from the L-1011 aircraft at 3:14 p.m. EST, propelling NASA's Solar Radiation and Climate Experiment (SORCE) toward its orbit. Separation of the spacecraft from the rocket occurred 10 minutes and 46 seconds after launch at about 3:24 p.m. Initial contact with the satellite was made seven seconds after separation via a NASA communications satellite network. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

KSC-03pd0183

NASA Image and Video Library

2003-01-25

KENNEDY SPACE CENTER, FLA. - After takeoff off from Cape Canaveral Air Force Station, Fla., the Pegasus XL rocket, with NASA's Solar Radiation and Climate Experiment (SORCE), can be seen attached underneath and between the wheels of the L-1011 aircraft. The L-1011 will release the rocket over the Atlantic Ocean at 39,000 feet. After separation from the rocket, initial contact with the satellite will be made and the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado.

KSC-03pd0180

NASA Image and Video Library

2003-01-25

KENNEDY SPACE CENTER, FLA. -- The Pegasus XL rocket is dropped from the L-1011 aircraft at 3:14 p.m. EST, propelling NASA's Solar Radiation and Climate Experiment (SORCE) toward its orbit. Separation of the spacecraft from the rocket occurred 10 minutes and 46 seconds after launch at about 3:24 p.m. Initial contact with the satellite was made seven seconds after separation via a NASA communications satellite network. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

[Health advocacy in violence against women: an experience].

PubMed

Vives-Cases, Carmen; Alvarez-Dardet, Carlos; Colomer, Concha; Bertomeu, Angustias

2005-01-01

The development of political responses to a problem needs for its construction as a social problem of a continuous epidemiological surveillance system available for the affected public and key decision makers. A women's health advocacy net based initiative was launched in November 2003. Every month the epidemic index of deaths (ratio of deaths in that month and median of deaths occurring the previous 5 years) due to Intimate Partner Violence (IPV) is published in a section called "Violence Alert" of e-leusis.net a women's web page. The objective was giving visibility to information contributing to shape the problem. from a population perspective. The initiative was introduced at the beginning to journalists and every month a press release with the index results and a comment on it is circulated. More than half of the months studied (January 2003-December 2004) were epidemic (epidemic indexb > or = 1.25). "Violence alert" has received 2330 visits since then, an average of 65 visits per week. The page attracted media coverage from radio, TV and newspapers.

Performance of the dark energy camera liquid nitrogen cooling system

NASA Astrophysics Data System (ADS)

Cease, H.; Alvarez, M.; Alvarez, R.; Bonati, M.; Derylo, G.; Estrada, J.; Flaugher, B.; Flores, R.; Lathrop, A.; Munoz, F.; Schmidt, R.; Schmitt, R. L.; Schultz, K.; Kuhlmann, S.; Zhao, A.

2014-01-01

The Dark Energy Camera, the Imager and its cooling system was installed onto the Blanco 4m telescope at the Cerro Tololo Inter-American Observatory in Chile in September 2012. The imager cooling system is a LN2 two-phase closed loop cryogenic cooling system. The cryogenic circulation processing is located off the telescope. Liquid nitrogen vacuum jacketed transfer lines are run up the outside of the telescope truss tubes to the imager inside the prime focus cage. The design of the cooling system along with commissioning experiences and initial cooling system performance is described. The LN2 cooling system with the DES imager was initially operated at Fermilab for testing, then shipped and tested in the Blanco Coudé room. Now the imager is operating inside the prime focus cage. It is shown that the cooling performance sufficiently cools the imager in a closed loop mode, which can operate for extended time periods without maintenance or LN2 fills.

Design and Operation of the RHIC 80-K Cooler

NASA Astrophysics Data System (ADS)

Nicoletti, A.; Reuter, A.; Sidi-Yekhlef, A.; Talty, P.; Quimby, E.

2004-06-01

A stand-alone cryogenic system designed to maintain the magnets of the Relativistic Heavy Ion Collider (RHIC) at between 80 and 100 K during accelerator shutdown periods has been conceived and designed at Brookhaven National Laboratory and built by PHPK Technologies of Columbus, Ohio. Since most thermal contraction occurs above this temperature, this unit, referred to as the 80-K Cooler, will eliminate the stresses associated with thermal cycling. The cooling system will provide the necessary refrigeration by circulating cooled helium gas at approximately 1500 kPA through the RHIC heat shields and magnets. This helium is cooled by heat exchange with liquid nitrogen and circulated via three cold centrifugal pumps. The nominal delivered cooling capacity required to maintain the magnets at temperature is approximately 36 kW, primarily intercepted at the heat shield. The system also has separate heat exchangers for use as a pre-cooler from room temperature to 82 K. Selection of sextant or sextants for pre-cooling is designed into the RHIC cryogenic distribution system. Topics covered include Cooler design decisions, details of the Cooler as built, integration into the existing RHIC cryogenic system and initial operating experience.

Coronary Heart Disease Alters Intercellular Communication by Modifying Microparticle-Mediated MicroRNA Transport

PubMed Central

Finn, Nnenna A.; Eapen, Danny; Manocha, Pankaj; Kassem, Hatem Al; Lassegue, Bernard; Ghasemzadeh, Nima; Quyyumi, Arshed; Searles, Charles D.

2013-01-01

Coronary heart disease (CHD) is characterized by abnormal intercellular communication and circulating microRNAs (miRNAs) are likely involved in this process. Here, we show that CHD was associated with changes in the transport of circulating miRNA, particularly decreased miRNA enrichment in microparticles (MPs). Additionally, MPs from CHD patients were less efficient at transferring miRNA to cultured HUVECs, which correlated with their diminished capacity to bind developmental endothelial locus-1 (Del-1). In summary, CHD was associated with distinct changes in circulating miRNA transport and these changes may contribute to the abnormal intercellular communication that underlies CHD initiation and progression. PMID:24042051

Research on Parallel Three Phase PWM Converters base on RTDS

NASA Astrophysics Data System (ADS)

Xia, Yan; Zou, Jianxiao; Li, Kai; Liu, Jingbo; Tian, Jun

2018-01-01

Converters parallel operation can increase capacity of the system, but it may lead to potential zero-sequence circulating current, so the control of circulating current was an important goal in the design of parallel inverters. In this paper, the Real Time Digital Simulator (RTDS) is used to model the converters parallel system in real time and study the circulating current restraining. The equivalent model of two parallel converters and zero-sequence circulating current(ZSCC) were established and analyzed, then a strategy using variable zero vector control was proposed to suppress the circulating current. For two parallel modular converters, hardware-in-the-loop(HIL) study based on RTDS and practical experiment were implemented, results prove that the proposed control strategy is feasible and effective.

HER2 expression identifies dynamic functional states within circulating breast cancer cells.

PubMed

Jordan, Nicole Vincent; Bardia, Aditya; Wittner, Ben S; Benes, Cyril; Ligorio, Matteo; Zheng, Yu; Yu, Min; Sundaresan, Tilak K; Licausi, Joseph A; Desai, Rushil; O'Keefe, Ryan M; Ebright, Richard Y; Boukhali, Myriam; Sil, Srinjoy; Onozato, Maristela L; Iafrate, Anthony J; Kapur, Ravi; Sgroi, Dennis; Ting, David T; Toner, Mehmet; Ramaswamy, Sridhar; Haas, Wilhelm; Maheswaran, Shyamala; Haber, Daniel A

2016-09-01

Circulating tumour cells in women with advanced oestrogen-receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer acquire a HER2-positive subpopulation after multiple courses of therapy. In contrast to HER2-amplified primary breast cancer, which is highly sensitive to HER2-targeted therapy, the clinical significance of acquired HER2 heterogeneity during the evolution of metastatic breast cancer is unknown. Here we analyse circulating tumour cells from 19 women with ER + /HER2 - primary tumours, 84% of whom had acquired circulating tumour cells expressing HER2. Cultured circulating tumour cells maintain discrete HER2 + and HER2 - subpopulations: HER2 + circulating tumour cells are more proliferative but not addicted to HER2, consistent with activation of multiple signalling pathways; HER2 - circulating tumour cells show activation of Notch and DNA damage pathways, exhibiting resistance to cytotoxic chemotherapy, but sensitivity to Notch inhibition. HER2 + and HER2 - circulating tumour cells interconvert spontaneously, with cells of one phenotype producing daughters of the opposite within four cell doublings. Although HER2 + and HER2 - circulating tumour cells have comparable tumour initiating potential, differential proliferation favours the HER2 + state, while oxidative stress or cytotoxic chemotherapy enhances transition to the HER2 - phenotype. Simultaneous treatment with paclitaxel and Notch inhibitors achieves sustained suppression of tumorigenesis in orthotopic circulating tumour cell-derived tumour models. Together, these results point to distinct yet interconverting phenotypes within patient-derived circulating tumour cells, contributing to progression of breast cancer and acquisition of drug resistance.

Identification, emergence and mobilization of circulating endothelial cells or progenitors in the embryo.

PubMed

Pardanaud, Luc; Eichmann, Anne

2006-07-01

Using quail-chick parabiosis and QH1 monoclonal antibody analysis, we have identified circulating endothelial cells and/or progenitors in the embryo. These cells were already present early in ontogeny, before the third embryonic day. Under normal conditions, they integrated into most tissues but remained scarce. When experimental angiogenic responses were induced by wounding or grafts onto the chorioallantoic membrane, circulating endothelial cells were rapidly mobilized and selectively integrated sites of neoangiogenesis. Their mobilization was not dependent on the presence of the bone marrow as it was effective before its differentiation. Surprisingly, mobilization was not effective during sprouting angiogenesis following VEGF treatment of chorioallantoic membrane. Thus, embryonic circulating endothelial cells were efficiently mobilized during the establishment of an initial vascular supply to ischemic tissues following wounding or grafting, but were not involved during classical sprouting angiogenesis.

Importance of convective parameterization in ENSO predictions

NASA Astrophysics Data System (ADS)

Zhu, Jieshun; Kumar, Arun; Wang, Wanqiu; Hu, Zeng-Zhen; Huang, Bohua; Balmaseda, Magdalena A.

2017-06-01

This letter explored the influence of atmospheric convection scheme on El Niño-Southern Oscillation (ENSO) predictions using a set of hindcast experiments. Specifically, a low-resolution version of the Climate Forecast System version 2 is used for 12 month hindcasts starting from each April during 1982-2011. The hindcast experiments are repeated with three atmospheric convection schemes. All three hindcasts apply the identical initialization with ocean initial conditions taken from the European Centre for Medium-Range Weather Forecasts and atmosphere/land initial states from the National Centers for Environmental Prediction. Assessments indicate a substantial sensitivity of the sea surface temperature prediction skill to the different convection schemes, particularly over the eastern tropical Pacific. For the Niño 3.4 index, the anomaly correlation skill can differ by 0.1-0.2 at lead times longer than 2 months. Long-term simulations are further conducted with the three convection schemes to understand the differences in prediction skill. By conducting heat budget analyses for the mixed-layer temperature anomalies, it is suggested that the convection scheme having the highest skill simulates stronger and more realistic coupled feedbacks related to ENSO. Particularly, the strength of the Ekman pumping feedback is better represented, which is traced to more realistic simulation of surface wind stress. Our results imply that improving the mean state simulations in coupled (ocean-atmosphere) general circulation model (e.g., ameliorating the Intertropical Convergence Zone simulation) might further improve our ENSO prediction capability.

Hydrodechlorination of TCE in a circulated electrolytic column at high flow rate.

PubMed

Fallahpour, Noushin; Yuan, Songhu; Rajic, Ljiljana; Alshawabkeh, Akram N

2016-02-01

Palladium-catalytic hydrodechlorination of trichloroethylene (TCE) by cathodic H2 produced from water electrolysis has been tested. For a field in-well application, the flow rate is generally high. In this study, the performance of Pd-catalytic hydrodechlorination of TCE using cathodic H2 is evaluated under high flow rate (1 L min(-1)) in a circulated column system, as expected to occur in practice. An iron anode supports reduction conditions and it is used to enhance TCE hydrodechlorination. However, the precipitation occurs and high flow rate was evaluated to minimize its adverse effects on the process (electrode coverage, clogging, etc.). Under the conditions of 1 L min(-1) flow, 500 mA current, and 5 mg L(-1) initial TCE concentration, removal efficacy using iron anodes (96%) is significantly higher than by mixed metal oxide (MMO) anodes (66%). Two types of cathodes (MMO and copper foam) in the presence of Pd/Al2O3 catalyst under various currents (250, 125, and 62 mA) were used to evaluate the effect of cathode materials on TCE removal efficacy. The similar removal efficiencies were achieved for both cathodes, but more precipitation generated with copper foam cathode (based on the experiments done by authors). In addition to the well-known parameters such as current density, electrode materials, and initial TCE concentration, the high velocities of groundwater flow can have important implications, practically in relation to the flush out of precipitates. For potential field application, a cost-effective and sustainable in situ electrochemical process using a solar panel as power supply is being evaluated. Published by Elsevier Ltd.

Hydrodechlorination of TCE in a circulated electrolytic column at high flow rate

PubMed Central

Fallahpour, Noushin; Yuan, Songhu; Rajic, Ljiljana; Alshawabkeh, Akram N.

2015-01-01

Palladium-catalytic hydrodechlorination of trichloroethylene (TCE) by cathodic H2 produced from water electrolysis has been tested. For a field in-well application, the flow rate is generally high. In this study, the performance of Pd-catalytic hydrodechlorination of TCE using cathodic H2 is evaluated under high flow rate (1 L min−1) in a circulated column system, as expected to occur in practice. An iron anode supports reduction conditions and it is used to enhance TCE hydrodechlorination. However, the precipitation occurs and high flow rate was evaluated to minimize its advers effects on the process (electrode coverage, clogging, etc.). Under the conditions of 1 L min−1 flow, 500 mA current, and 5 mg L−1 initial TCE concentration, removal efficacy using iron anodes (96%) is significantly higher than by mixed metal oxide (MMO) anodes (66%). Two types of cathodes (MMO and copper foam) in the presence of Pd/Al2O3 catalyst under various currents (250, 125, and 62 mA) were used to evaluate the effect of cathode materials on TCE removal efficacy. The similar removal efficiencies were achieved for both cathodes, but more precipitation generated with copper foam cathode (based on the experiments done by authors). In addition to the well-known parameters such as current density, electrode materials, and initial TCE concentration, the high velocities of groundwater flow can have important implications, practically in relation to the flush out of precipitates. For potential field application, a cost-effective and sustainable in situ electrochemical process using a solar panel as power supply is being evaluated. PMID:26344148

In vivo label-free photoacoustic flow cytography and on-the-spot laser killing of single circulating melanoma cells

NASA Astrophysics Data System (ADS)

He, Yun; Wang, Lidai; Shi, Junhui; Yao, Junjie; Li, Lei; Zhang, Ruiying; Huang, Chih-Hsien; Zou, Jun; Wang, Lihong V.

2016-12-01

Metastasis causes as many as 90% of cancer-related deaths, especially for the deadliest skin cancer, melanoma. Since hematogenous dissemination of circulating tumor cells is the major route of metastasis, detection and destruction of circulating tumor cells are vital for impeding metastasis and improving patient prognosis. Exploiting the exquisite intrinsic optical absorption contrast of circulating melanoma cells, we developed dual-wavelength photoacoustic flow cytography coupled with a nanosecond-pulsed melanoma-specific laser therapy mechanism. We have successfully achieved in vivo label-free imaging of rare single circulating melanoma cells in both arteries and veins of mice. Further, the photoacoustic signal from a circulating melanoma cell immediately hardware-triggers a lethal pinpoint laser irradiation to kill it on the spot in a thermally confined manner without causing collateral damage. A pseudo-therapy study including both in vivo and in vitro experiments demonstrated the performance and the potential clinical value of our method, which can facilitate early treatment of metastasis by clearing circulating tumor cells from vasculature.

Circulation and Purification in the LUX-ZEPLIN System Test

NASA Astrophysics Data System (ADS)

Alsum, Shaun; Lz Collaboration

2016-03-01

LZ is a dark-matter direct detection experiment whose detector is a two-phase TPC using approximately seven tons of active xenon as its scintillator. The xenon must have few electronegative impurities to ensure sufficient electron transport through the drift region. The LZ purification system is being prototyped in the LZ system test, a test platform located at SLAC using about 100kg of Xenon, which consists of gas circulation through a SAES getter. We utilize a dual-phase and a gas-phase heat exchanger to reduce needed cooling power. To achieve this circulation we employ an all metal seal triple diaphragm pump, also prototyped in the System Test. This talk will present early results from the system test as well as some baseline LZ designs. The LUX-ZEPLIN dark matter direct detection experiment.

A general circulation model study of the solar and QBO modulation of the stratospheric circulation during the northern hemisphere winter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodera, Kunihiko; Chiba, Masaru; Shibata, Kiyotaka

1991-07-01

A general circulation model has been used to study the modulation of north-polar temperatures during winter by both solar activity and the equatorial quasi-biennial oscillation (QBO). The variation of solar activity was simulated by changing the heating rate due to the absorption of ultraviolet (UV) radiation by ozone, while the QBO zonal wind fields were reproduced by incorporating zonal-momentum sources in the equatorial stratosphere. A total of 10 experiments were conducted by changing the heating rate from 70 to 110% for each of the simulated QBO easterly and westerly cases. The results of the numerical experiments show modulation effects similarmore » to those found by Labitzke (1987) in the 30-mb temperatures at the North Pole.« less

Use of Ocean Remote Sensing Data to Enhance Predictions with a Coupled General Circulation Model

NASA Technical Reports Server (NTRS)

Rienecker, Michele M.

1999-01-01

Surface height, sea surface temperature and surface wind observations from satellites have given a detailed time sequence of the initiation and evolution of the 1997/98 El Nino. The data have beet complementary to the subsurface TAO moored data in their spatial resolution and extent. The impact of satellite observations on seasonal prediction in the tropical Pacific using a coupled ocean-atmosphere general circulation model will be presented.

Sealed operation, and circulation and purification of gas in the HARPO TPC

NASA Astrophysics Data System (ADS)

Frotin, M.; Gros, P.; Attié, D.; Bernard, D.; Dauvois, V.; Delbart, A.; Durand, D.; Geerebaert, Y.; Legand, S.; Magnier, P.; Poilleux, P.; Semeniouk, I.

2018-02-01

HARPO is a time projection chamber (TPC) demonstrator of a gamma-ray telescope and polarimeter in the MeV-GeV range, for a future space mission. We present the evolution of the TPC performance over a five month sealed-mode operation, by the analysis of cosmic-ray data, followed by the fast and complete recovery of the initial gas properties using a lightweight gas circulation and purification system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daleu, C. L.; Plant, R. S.; Woolnough, S. J.

Here, as part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistentmore » implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.« less

Numerical experiments with a general circulation model concerning the distribution of ozone in the stratosphere

NASA Technical Reports Server (NTRS)

Kurzeja, R. J.; Haggard, K. V.; Grose, W. L.

1984-01-01

The distribution of ozone below 60 km altitude has been simulated in two experiments employing a nine-layer quasi-geostrophic spectral model and linear parameterization of ozone photochemistry, the first of which included thermal and orographic forcing of the planetary scale waves, while the second omitted it. The first experiment exhibited a high latitude winter ozone buildup which was due to a Brewer-Dodson circulation forced by large amplitude (planetary scale) waves in the winter lower stratosphere. Photochemistry was also found to be important down to lower altitudes (20 km) in the summer stratosphere than had previously been supposed.

Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing

NASA Astrophysics Data System (ADS)

Vecchi, Gabriel A.; Soden, Brian J.; Wittenberg, Andrew T.; Held, Isaac M.; Leetmaa, Ants; Harrison, Matthew J.

2006-05-01

Since the mid-nineteenth century the Earth's surface has warmed, and models indicate that human activities have caused part of the warming by altering the radiative balance of the atmosphere. Simple theories suggest that global warming will reduce the strength of the mean tropical atmospheric circulation. An important aspect of this tropical circulation is a large-scale zonal (east-west) overturning of air across the equatorial Pacific Ocean-driven by convection to the west and subsidence to the east-known as the Walker circulation. Here we explore changes in tropical Pacific circulation since the mid-nineteenth century using observations and a suite of global climate model experiments. Observed Indo-Pacific sea level pressure reveals a weakening of the Walker circulation. The size of this trend is consistent with theoretical predictions, is accurately reproduced by climate model simulations and, within the climate models, is largely due to anthropogenic forcing. The climate model indicates that the weakened surface winds have altered the thermal structure and circulation of the tropical Pacific Ocean. These results support model projections of further weakening of tropical atmospheric circulation during the twenty-first century.

Summer circulation in the Mexican tropical Pacific

NASA Astrophysics Data System (ADS)

Trasviña, A.; Barton, E. D.

2008-05-01

The main components of large-scale circulation of the eastern tropical Pacific were identified in the mid 20th century, but the details of the circulation at length scales of 10 2 km or less, the mesoscale field, are less well known particularly during summer. The winter circulation is characterized by large mesoscale eddies generated by intense cross-shore wind pulses. These eddies propagate offshore to provide an important source of mesoscale variability for the eastern tropical Pacific. The summer circulation has not commanded similar attention, the main reason being that the frequent generation of hurricanes in the area renders in situ observations difficult. Before the experiment presented here, the large-scale summer circulation of the Gulf of Tehuantepec was thought to be dominated by a poleward flow along the coast. A drifter-deployment experiment carried out in June 2000, supported by satellite altimetry and wind data, was designed to characterize this hypothesized Costa Rica Coastal Current. We present a detailed comparison between altimetry-estimated geostrophic and in situ currents estimated from drifters. Contrary to expectation, no evidence of a coherent poleward coastal flow across the gulf was found. During the 10-week period of observations, we documented a recurrent pattern of circulation within 500 km of shore, forced by a combination of local winds and the regional-scale flow. Instead of the Costa Rica Coastal Current, we found a summer eddy field capable of influencing large areas of the eastern tropical Pacific. Even in summer, the cross-isthmus wind jet is capable of inducing eddy formation.

Assimilation of Tropical Cyclone Track and Wind Radius Data with an Ensemble Kalman Filter

NASA Astrophysics Data System (ADS)

Kunii, M.

2014-12-01

Improving tropical cyclone (TC) forecasts is one of the most important issues in meteorology, but TC intensity forecasts are a challenging task. Because the lack of observations near TCs usually results in degraded accuracy of initial fields, utilizing TC advisory data in data assimilation typically has started with an ensemble Kalman filtering (EnKF). In this study, TC intensity and position information was directly assimilated using the EnKF, and the impact of these observations was investigated by comparing different assimilation strategies. Another experiment with TC wind radius data was carried out to examine the influence of TC shape parameters. Sensitivity experiments indicated that the assimilation of TC intensity and position data yielded results that were superior to those based on conventional assimilation of TC minimum sea level pressure as a standard surface pressure observation. Assimilation of TC radius data modified TC outer circulations closer to observations. The impacts of these TC parameters were also evaluated using the case of Typhoon Talas in 2011. The TC intensity, position, and wind radius data led to improved TC track forecasts and thence to improved precipitation forecasts. These results imply that initialization with these TC-related observations benefits TC forecasts, offering promise for the prevention and mitigation of natural disasters caused by TCs.

Gulf of Mexico physical-oceanography program final report: years 1 and 2. Volume 1. Executive summary. Technical report, 1983-1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

In 1982, Minerals Management Service (MMS) initiated a multi-year program under contract with Science Applications International Corp. (SAIC) to study the physical oceanography of the Gulf of Mexico as part of its outer continental shelf environmental-studies programs. This particular program, called the Gulf of Mexico Physical Oceanography Program (GOMPOP), has two primary goals: (1) develop a better understanding and description of conditions and processes governing Gulf circulation; and (2) establish a data base that could be used as initial and boundary conditions by a companion MMS-funded numerical circulation-modeling program. The report presents results from the first two of three yearsmore » of observations in the eastern Gulf.« less

Some Measures of Cost Effectiveness in Library Collections.

ERIC Educational Resources Information Center

Hamaker, Charles A.

1992-01-01

Describes measures of cost effectiveness that are useful for academic library collections, based on experiences at the Louisiana State University libraries. Highlights include circulation analysis of newly cataloged books; current periodical use compared to cost; faculty ranking of journals; and circulation patterns (i.e., use versus cost and…

Circulatory shear flow alters the viability and proliferation of circulating colon cancer cells

NASA Astrophysics Data System (ADS)

Fan, Rong; Emery, Travis; Zhang, Yongguo; Xia, Yuxuan; Sun, Jun; Wan, Jiandi

2016-06-01

During cancer metastasis, circulating tumor cells constantly experience hemodynamic shear stress in the circulation. Cellular responses to shear stress including cell viability and proliferation thus play critical roles in cancer metastasis. Here, we developed a microfluidic approach to establish a circulatory microenvironment and studied circulating human colon cancer HCT116 cells in response to a variety of magnitude of shear stress and circulating time. Our results showed that cell viability decreased with the increase of circulating time, but increased with the magnitude of wall shear stress. Proliferation of cells survived from circulation could be maintained when physiologically relevant wall shear stresses were applied. High wall shear stress (60.5 dyne/cm2), however, led to decreased cell proliferation at long circulating time (1 h). We further showed that the expression levels of β-catenin and c-myc, proliferation regulators, were significantly enhanced by increasing wall shear stress. The presented study provides a new insight to the roles of circulatory shear stress in cellular responses of circulating tumor cells in a physiologically relevant model, and thus will be of interest for the study of cancer cell mechanosensing and cancer metastasis.

Vertical Distribution of Radiation Stress for Non-linear Shoaling Waves

NASA Astrophysics Data System (ADS)

Webb, B. M.; Slinn, D. N.

2004-12-01

The flux of momentum directed shoreward by an incident wave field, commonly referred to as the radiation stress, plays a significant role in nearshore circulation and, therefore, has a profound impact on the transport of pollutants, biota, and sediment in nearshore systems. Having received much attention since the seminal work of Longuet-Higgins and Stewart in the early 1960's, use of the radiation stress concept continues to be refined and evidence of its utility is widespread in literature pertaining to coastal and ocean science. A number of investigations, both numerical and analytical in nature, have used the concept of the radiation stress to derive appropriate forcing mechanisms that initiate cross-shore and longshore circulation, but typically in a depth-averaged sense due to a lack of information concerning the vertical distribution of the wave stresses. While depth-averaged nearshore circulation models are still widely used today, advancements in technology have permitted the adaptation of three-dimensional (3D) modeling techniques to study flow properties of complex nearshore circulation systems. It has been shown that the resulting circulation in these 3D models is very sensitive to the vertical distribution of the nearshore forcing, which have often been implemented as either depth-uniform or depth-linear distributions. Recently, analytical expressions describing the vertical structure of radiation stress components have appeared in the literature (see Mellor, 2003; Xia et al., 2004) but do not fully describe the magnitude and structure in the region bound by the trough and crest of non-linear, propagating waves. Utilizing a three-dimensional, non-linear, numerical model that resolves the time-dependent free surface, we present mean flow properties resulting from a simulation of Visser's (1984, 1991) laboratory experiment on uniform longshore currents. More specifically, we provide information regarding the vertical distribution of radiation stress components (Sxx and Sxy) resulting from obliquely incident, non-linear shoaling waves. Vertical profiles of the radiation stress components predicted by the numerical model are compared with published analytical solutions, expressions given by linear theory, and observations from an investigation employing second-order cnoidal wave theory.

Simulating surface oil transport during the Deepwater Horizon oil spill: Experiments with the BioCast system

NASA Astrophysics Data System (ADS)

Jolliff, Jason Keith; Smith, Travis A.; Ladner, Sherwin; Arnone, Robert A.

2014-03-01

The U.S. Naval Research Laboratory (NRL) is developing nowcast/forecast software systems designed to combine satellite ocean color data streams with physical circulation models in order to produce prognostic fields of ocean surface materials. The Deepwater Horizon oil spill in the Gulf of Mexico provided a test case for the Bio-Optical Forecasting (BioCast) system to rapidly combine the latest satellite imagery of the oil slick distribution with surface circulation fields in order to produce oil slick transport scenarios and forecasts. In one such sequence of experiments, MODIS satellite true color images were combined with high-resolution ocean circulation forecasts from the Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS®) to produce 96-h oil transport simulations. These oil forecasts predicted a major oil slick landfall at Grand Isle, Louisiana, USA that was subsequently observed. A key driver of the landfall scenario was the development of a coastal buoyancy current associated with Mississippi River Delta freshwater outflow. In another series of experiments, longer-term regional circulation model results were combined with oil slick source/sink scenarios to simulate the observed containment of surface oil within the Gulf of Mexico. Both sets of experiments underscore the importance of identifying and simulating potential hydrodynamic conduits of surface oil transport. The addition of explicit sources and sinks of surface oil concentrations provides a framework for increasingly complex oil spill modeling efforts that extend beyond horizontal trajectory analysis.

A Study of VITOM in Pediatric Surgery and Urology: Evaluation of Technology Acceptance and Usability by Operating Team and Surgeon Musculoskeletal Discomfort.

PubMed

Frykman, Philip K; Freedman, Andrew L; Kane, Timothy D; Cheng, Zhi; Petrosyan, Mikael; Catchpole, Kenneth

2017-02-01

We studied operating team acceptability of Video Telescopic Monitor (VITOM ® ) exoscope by exploring the ease of use of the device in two centers. We also assessed factors affecting surgeon musculoskeletal discomfort. We focused on how the operating team interacted with the VITOM system with surrogate measures of usefulness, image quality, ease of use, workload, and setup time. Multivariable linear regression was used to model the relationships between team role, experience, and setup time. Relationships between localized musculoskeletal discomfort and use of VITOM alone, and with loupes, were also analyzed. Four surgeons, 7 surgical techs, 7 circulating nurses, and 13 surgical residents performed 70 pediatric surgical and urological operations. We found that subjective views of each team member were consistently positive with 69%-74% agreed or strongly agreed that VITOM enhanced their ability to perform their job and improved the surgical process. Unexpectedly, the scrub techs and nurses perceived more value and utility of VITOM, presumably because it provides them a view of the operative field that would otherwise be unavailable to them. Team members rated perceptions of image quality highly and workload generally satisfactory. Not surprisingly, setup time decreased with team experience and multivariable modeling showed significant correlations with surgeon and surgical tech experience, but not circulating nurse. An important finding was that surgeon neck discomfort was reduced with use of VITOM alone for magnification, compared with use of loupes and VITOM. The most likely explanation for these findings is improved posture with the neck at a neutral position when viewing the VITOM images, compared with neck flexion with loupes, and thus, a less favorable ergonomic position. This study suggests that there may be small drawbacks associated with VITOM use initially, but these reduce with increased experience and benefit both the surgeon and the rest of the team.

Activities relating to understanding the initiation, organization and structure of moist convection in the Southeast environment

NASA Technical Reports Server (NTRS)

Mcnider, Richard T.

1992-01-01

In the spring and summer of 1986, NASA/Marshall Space Flight Center (MSFC) will sponsor the Satellite Precipitation And Cloud Experiment (SPACE) to be conducted in the Central Tennessee, Northern Alabama, and Northeastern Mississippi area. The field program will incorporate high altitude flight experiments associated with meteorological remote sensor development for future space flight, and an investigation of precipitation processes associated with mesoscale and small convective systems. In addition to SPACE, the MIcroburst and Severe Thunderstorm (MIST) program, sponsored by the National Science Foundation (NSF), and the FAA-Lincoln Laboratory Operational Weather Study (FLOWS), sponsored by the Federal Aviation Administration (FAA), will take place concurrently within the SPACE experiment area. All three programs (under the joint acronym COHMEX (COoperative Huntsville Meteorological EXperiment)) will provide a data base for detailed analysis of mesoscale convective systems while providing ground truth comparisons for remote sensor evaluation. The purpose of this document is to outline the experiment design criteria for SPACE, and describe the special observing facilities and data sets that will be available under the COHMEX joint program. In addition to the planning of SPACE-COHMEX, this document covers three other parts of the program. The field program observations' main activity was the operation of an upper air rawinsonde network to provide ground truth for aircraft and spacecraft observations. Another part of the COHMEX program involved using boundary layer mesoscale models to study and simulate the initiation and organization of moist convection due to mesoscale thermal and mechanical circulations. The last part of the program was the collection, archival and distribution of the resulting COHMEX-SPACE data sets.

Anthropogenic Influence on the Changes of the Subtropical Gyre Circulation in the South Pacific in the 20th Century

NASA Astrophysics Data System (ADS)

Albrecht, F.; Pizarro, O.; Montecinos, A.

2016-12-01

The subtropical ocean gyre in the South Pacific is a large scale wind-driven ocean circulation, including the Peru-Chile Current, the westward South Equatorial Current, the East Australian Current, and the eastward South Pacific Current. Large scale ocean circulations play an essential role in the climate of the Earth over long and short term time scales.In the recent years a spin-up of this circulation has been recognized analyzing observations of sea level, temperature and salinity profiles, sea surface temperature and wind. Until now it is not clear whether this spin-up is decadal variability or whether it is a long-term trend introduced by anthropogenic forcing. This study aims to analyze whether and how anthropogenic forcing influences the position and the strength of the gyre in the 20th century. To determine that, yearly means of different variables of an ensemble of CMIP5 models are analyzed. The experiments 'historical' and 'historicalNat' are examined. The 'historical' experiment simulates the climate of the 20th century and the 'historicalNat' experiment covers the same time period, but only includes natural forcings. Comparing the outcomes of these two experiments is supposed to give information about the anthropogenic influence on the subtropical gyre of the South Pacific.The main variable we analyze is sea level change. This is directly related to the gyre circulation. The center of the gyre is characterized by a high pressure zone (high sea level) and the temporal and spatial variability of the sea level height field gives information about changes in the gyre circulation. The CMIP5 databank includes steric and dynamic sea level changes. Steric sea level, that is the contribution of temperature and salinity of the water, describes the major contribution to regional sea level change with respect to the global mean. Density changes contract or expand the water, which also changes the sea surface height. This does not only occur at the surface, but at all layers in the ocean. Sea level change thus integrates ocean variability throughout the depth of the ocean. Sea level simulations of the different experiments are compared using long-term trends, multi-year anomalies and EOF-Analysis. Changes in temperature and salinity in the deeper ocean are used to describe the development of the gyre below the surface.

Initial Steroid Sensitivity in Children with Steroid-Resistant Nephrotic Syndrome Predicts Post-Transplant Recurrence

PubMed Central

Ding, Wen Y.; Koziell, Ania; McCarthy, Hugh J.; Bierzynska, Agnieszka; Bhagavatula, Murali K.; Dudley, Jan A.; Inward, Carol D.; Coward, Richard J.; Tizard, Jane; Reid, Christopher; Antignac, Corinne; Boyer, Olivia

2014-01-01

Of children with idiopathic nephrotic syndrome, 10%–20% fail to respond to steroids or develop secondary steroid resistance (termed initial steroid sensitivity) and the majority progress to transplantation. Although 30%–50% of these patients suffer disease recurrence after transplantation, with poor long-term outcome, no reliable indicator of recurrence has yet been identified. Notably, the incidence of recurrence after transplantation appears reduced in patients with steroid-resistant nephrotic syndrome (SRNS) due to monogenic disorders. We reviewed 150 transplanted patients with SRNS to identify biomarkers that consistently predict outcome of SRNS after transplantation. In all, 25 children had genetic or familial SRNS and did not experience post-transplant recurrence. We reviewed phenotypic factors, including initial steroid sensitivity, donor type, age, ethnicity, time to ESRD, and time on dialysis, in the remaining 125 children. Of these patients, 57 (45.6%) developed post-transplant recurrence; 26 of 28 (92.9%) patients with initial steroid sensitivity recurred after transplantation, whereas only 26 of 86 (30.2%) patients resistant from the outset recurred (odds ratio, 30; 95% confidence interval, 6.62 to 135.86; P<0.001). We were unable to determine recurrence in two patients (one with initial steroid sensitivity), and nine patients did not receive initial steroids. Our data show that initial steroid sensitivity is highly predictive of post-transplant disease recurrence in this pediatric patient population. Because a pathogenic circulating permeability factor in nephrotic syndrome remains to be confirmed, we propose initial steroid sensitivity as a surrogate marker for post-transplant recurrence. PMID:24511128

Mechanical circulatory support of a univentricular Fontan circulation with a continuous axial-flow pump in a piglet model.

PubMed

Wei, Xufeng; Sanchez, Pablo G; Liu, Yang; Li, Tieluo; Watkins, A Claire; Wu, Zhongjun J; Griffith, Bartley P

2015-01-01

Despite the significant contribution of the Fontan procedure to the therapy of complex congenital heart diseases, many patients progress to failure of their Fontan circulation. The use of ventricular assist devices to provide circulatory support to these patients remains challenging. In the current study, a continuous axial-flow pump was used to support a univentricular Fontan circulation. A modified Fontan circulation (atrio-pulmonary connection) was constructed in six Yorkshire piglets (8-14 kg). A Dacron conduit (12 mm) with two branches was constructed to serve as a complete atrio-pulmonary connection without the use of cardiopulmonary bypass. The Impella pump was inserted into the conduit through an additional Polytetrafluoroethylene (PTFE) graft in five animals. Hemodynamic data were collected for 6 hours under the supported Fontan circulation. The control animal died after initiating the Fontan circulation independent of resuscitation. Four pump supported animals remained hemodynamically stable for 6 hours with pump speeds between 18,000 rpm and 22,000 rpm (P1-P3). Oxygen saturation was maintained between 95% and 100%. Normal organ perfusion was illustrated by blood gas analysis and biochemical assays. A continuous axial-flow pump can be used for temporal circulatory support to the failing Fontan circulation as "bridge" to heart transplantation or recovery.

Coronary heart disease alters intercellular communication by modifying microparticle-mediated microRNA transport.

PubMed

Finn, Nnenna A; Eapen, Danny; Manocha, Pankaj; Al Kassem, Hatem; Lassegue, Bernard; Ghasemzadeh, Nima; Quyyumi, Arshed; Searles, Charles D

2013-11-01

Coronary heart disease (CHD) is characterized by abnormal intercellular communication and circulating microRNAs (miRNAs) are likely involved in this process. Here, we show that CHD was associated with changes in the transport of circulating miRNA, particularly decreased miRNA enrichment in microparticles (MPs). Additionally, MPs from CHD patients were less efficient at transferring miRNA to cultured HUVECs, which correlated with their diminished capacity to bind developmental endothelial locus-1 (Del-1). In summary, CHD was associated with distinct changes in circulating miRNA transport and these changes may contribute to the abnormal intercellular communication that underlies CHD initiation and progression. Published by Elsevier B.V.

Laboratory formation of non-cementing, methane hydrate-bearing sands

USGS Publications Warehouse

Waite, William F.; Bratton, Peter M.; Mason, David H.

2011-01-01

Naturally occurring hydrate-bearing sands often behave as though methane hydrate is acting as a load-bearing member of the sediment. Mimicking this behavior in laboratory samples with methane hydrate likely requires forming hydrate from methane dissolved in water. To hasten this formation process, we initially form hydrate in a free-gas-limited system, then form additional hydrate by circulating methane-supersaturated water through the sample. Though the dissolved-phase formation process can theoretically be enhanced by increasing the pore pressure and flow rate and lowering the sample temperature, a more fundamental concern is preventing clogs resulting from inadvertent methane bubble formation in the circulation lines. Clog prevention requires careful temperature control throughout the circulation loop.

An Oceanographic Perspective on the Charney Report

NASA Astrophysics Data System (ADS)

Wunsch, C. I.

2009-12-01

The Charney report (“Carbon Dioxide and Climate: A Scientific Assessment”, NRC 1979) was produced early in the discussions of oncoming climate change. Despite the somewhat crude understanding in 1979, its climate sensitivity estimates have proven remarkably stable over the past three decades. From the perspective of an oceanographic member of the Committee, the deliberations made it clear how primitive knowledge was of the ocean circulation at that time. The inability to say very much about how rapidly the ocean would take up carbon and heat led to the formulation and conduct of the World Ocean Circulation Experiment (WOCE) and associated programs such as the Joint Global Ocean Flux Study (JGOFS). Thus one less-obvious outcome of the Report was the various initiatives that brought a revolution in understanding of the ocean circulation and its climate impacts. That the range of uncertainty has not been reduced from its 1979 estimate is in part a consequence of the discovery of many elements influencing climate sensitivities which were only marginally perceived by the Committee. The climate system is far better understood today, but as the scientific cliché has it, we now know much more about what we don’t know.. One unexpected result of the Report was the insistence---by the G. W. Bush Administration---that since the uncertainty range had not diminished, the US global change research program had been a waste of money. The inference was dealt with in yet another, much longer, NRC report, “Thinking Strategically: The Appropriate Use of Metrics for the Climate Change Science Program.”

Microbe-mediated transformations of marine dissolved organic matter during 2,100 years of natural incubation in the cold, oxic crust of the Mid-Atlantic Ridge.

NASA Astrophysics Data System (ADS)

Shah Walter, S. R.; Jaekel, U.; Huber, J. A.; Dittmar, T.; Girguis, P. R.

2015-12-01

On the western flank of the Mid-Atlantic Ridge, oxic seawater from the deep ocean is downwelled into the basaltic crust, supplying the crustal aquifer with an initial inoculum of organic matter and electron acceptors. Studies have shown that fluids circulating within the crust are minimally altered from original seawater, making this subsurface environment a unique natural experiment in which the fate of marine organic matter and the limitations of microbial adaptability in the context of reduced carbon supply can be examined. To make the subsurface crustal aquifer accessible, two CORK (Circulation Obviation Retrofit Kit) observatories have been installed at North Pond, a sediment-filled depression beneath the oligotrophic Sargasso Sea. Radiocarbon analysis of dissolved inorganic (DIC) and organic carbon (DOC) in samples recovered from these observatories show uncoupled aging between DOC and DIC with Δ14C values of DOC as low as -933‰ despite isolation from the open ocean for, at most, 2,100 years. This extreme value is part of a general trend of decreasing DOC δ13C and Δ14C values with increasing incubation time within the aquifer. Combined with reduced concentrations of DOC, our results argue for selective microbial oxidation of the youngest, most 13C-enriched components of downwelled DOC, possibly identifying these as characteristics of the more bioavailable fractions of deep-ocean dissolved organic matter. They also suggest that microbial oxidation during low-temperature hydrothermal circulation could be an important sink for aged marine dissolved organic matter.

Molecular Surveillance of Low Pathogenic Avian Influenza Viruses in Wild Birds across the United States: Inferences from the Hemagglutinin Gene

PubMed Central

Piaggio, Antoinette J.; Shriner, Susan A.; VanDalen, Kaci K.; Franklin, Alan B.; Anderson, Theodore D.; Kolokotronis, Sergios-Orestis

2012-01-01

A United States interagency avian influenza surveillance plan was initiated in 2006 for early detection of highly pathogenic avian influenza viruses (HPAIV) in wild birds. The plan included a variety of wild bird sampling strategies including the testing of fecal samples from aquatic areas throughout the United States from April 2006 through December 2007. Although HPAIV was not detected through this surveillance effort we were able to obtain 759 fecal samples that were positive for low pathogenic avian influenza virus (LPAIV). We used 136 DNA sequences obtained from these samples along with samples from a public influenza sequence database for a phylogenetic assessment of hemagglutinin (HA) diversity in the United States. We analyzed sequences from all HA subtypes except H5, H7, H14 and H15 to examine genetic variation, exchange between Eurasia and North America, and geographic distribution of LPAIV in wild birds in the United States. This study confirms intercontinental exchange of some HA subtypes (including a newly documented H9 exchange event), as well as identifies subtypes that do not regularly experience intercontinental gene flow but have been circulating and evolving in North America for at least the past 20 years. These HA subtypes have high levels of genetic diversity with many lineages co-circulating within the wild birds of North America. The surveillance effort that provided these samples demonstrates that such efforts, albeit labor-intensive, provide important information about the ecology of LPAIV circulating in North America. PMID:23226543

Community input requested

NASA Astrophysics Data System (ADS)

Fine, Rana A.; Walker, Dan

In June 1996, the National Research Council (NRC) formed the Committee on Major U.S. Oceanographic Research Programs to foster coordination among the large programs (e.g., World Ocean Circulation Experiment, Ocean Drilling Program, Ridge Interdisciplinary Global Experiment, and others) and examine their role in ocean research. In particular, the committee is charged with (1) enhancing information sharing and the coordinated implementation of the research plans of the major ongoing and future programs; (2) assisting the federal agencies and ocean sciences community in identifying gaps, as well as appropriate followon activities to existing programs; (3) making recommendations on how future major ocean programs should be planned, structured and organized; and (4) evaluating the impact of major ocean programs on the understanding of the oceans, development of research facilities, education, and collegiality in the academic community. The activity was initiated at the request of the National Science Foundation (NSF) Division of Ocean Sciences, is overseen by the NRC's Ocean Studies Board (OSB), and is funded by both NSF and the Office of Naval Research.

Detection of imported wild polioviruses and of vaccine-derived polioviruses by environmental surveillance in Egypt.

PubMed

Blomqvist, Soile; El Bassioni, Laila; El Maamoon Nasr, Eman M; Paananen, Anja; Kaijalainen, Svetlana; Asghar, Humayun; de Gourville, Esther; Roivainen, Merja

2012-08-01

Systematic environmental surveillance for poliovirus circulation has been conducted in Egypt since 2000. The surveillance has revealed three independent importations of wild-type poliovirus. In addition, several vaccine-derived polioviruses have been detected in various locations in Egypt. In addition to acute flaccid paralysis (AFP) surveillance, environmental surveillance can be used to monitor the wild poliovirus and vaccine-derived poliovirus circulation in populations in support of polio eradication initiatives.

Detection of Imported Wild Polioviruses and of Vaccine-Derived Polioviruses by Environmental Surveillance in Egypt

PubMed Central

El Bassioni, Laila; El Maamoon Nasr, Eman M.; Paananen, Anja; Kaijalainen, Svetlana; Asghar, Humayun; de Gourville, Esther; Roivainen, Merja

2012-01-01

Systematic environmental surveillance for poliovirus circulation has been conducted in Egypt since 2000. The surveillance has revealed three independent importations of wild-type poliovirus. In addition, several vaccine-derived polioviruses have been detected in various locations in Egypt. In addition to acute flaccid paralysis (AFP) surveillance, environmental surveillance can be used to monitor the wild poliovirus and vaccine-derived poliovirus circulation in populations in support of polio eradication initiatives. PMID:22582070

Role of radiative-convective feedbacks in tropical cyclogenesis in rotating radiative-convective equilibrium simulations

NASA Astrophysics Data System (ADS)

Wing, A. A.; Camargo, S. J.; Sobel, A. H.

2015-12-01

"Self-aggregation" is a mode of convective organization found in idealized numerical simulations, in which there is a spontaneous transition from randomly distributed to organized convection despite homogeneous boundary conditions. Self-aggregation has primarily been studied in a non-rotating framework, but it has been hypothesized to be important to tropical cyclogenesis. In numerical simulations of tropical cyclones, a broad vortex or saturated column is often used to initialize the circulation. Here, we instead allow a circulation to develop spontaneously from a homogeneous environment in 3-d cloud-resolving simulations of radiative-convective equilibrium in a rotating framework, with interactive radiation and surface fluxes and fixed sea surface temperature. The goals of this study are two-fold: to study tropical cyclogenesis in an unperturbed environment free from the influence of a prescribed initial vortex or external disturbances, and to compare cyclogenesis to non-rotating self-aggregation. We quantify the feedbacks leading to tropical cyclogenesis using a variance budget equation for the vertically integrated frozen moist static energy. In the initial development of a broad circulation, the feedback processes are similar to the initial phase of non-rotating aggregation. Sensitivity tests in which the degree of interactive radiation is modified are also performed to determine the extent to which the radiative feedbacks that are essential to non-rotating self-aggregation are important for tropical cyclogenesis. Finally, we examine the evolution of the rotational and divergent flow, to determine the point at which rotation becomes important and the cyclogenesis process begins to differ from non-rotating aggregation.

High-Resolution Specification of the Land and Ocean Surface for Improving Regional Mesoscale Model Predictions

NASA Technical Reports Server (NTRS)

Case, Jonathan L.; Lazarus, Steven M.; Splitt, Michael E.; Crosson, William L.; Lapenta, William M.; Jedlovec, Gary J.; Peters-Lidard, Christa D.

2008-01-01

The exchange of energy and moisture between the Earth's surface and the atmospheric boundary layer plays a critical role in many meteorological processes. High-resolution, accurate representations of surface properties such as sea-surface temperature (SST), soil temperature and moisture content, ground fluxes, and vegetation are necessary to better understand the Earth-atmosphere interactions and improve numerical predictions of sensible weather. The NASA Short-term Prediction Research and Transition (SPoRT) Center has been conducting separate studies to examine the impacts of high-resolution land-surface initialization data from the Goddard Space Flight Center Land Information System (LIS) on subsequent WRF forecasts, as well as the influence of initializing WRF with SST composites derived from the MODIS instrument. This current project addresses the combined impacts of using high-resolution lower boundary data over both land (LIS data) and water (MODIS SSTs) on the subsequent daily WRF forecasts over Florida during May 2004. For this experiment, the WRF model is configured to run on a nested domain with 9- km and 3-kin grid spacing, centered on the Florida peninsula and adjacent coastal waters of the Gulf of Mexico and Atlantic Ocean. A control configuration of WRF is established to take all initial condition data from the NCEP Eta model. Meanwhile, two WRF experimental runs are configured to use high-resolution initialization data from (1) LIS land-surface data only, and (2) a combination of LIS data and high-resolution MODIS SST composites. The experiment involves running 24-hour simulations of the control WRF configuration, the MS-initialized WRF, and the LIS+MODIS-initialized WRF daily for the entire month of May 2004. All atmospheric data for initial and boundary conditions for the Control, LIS, and LIS+MODIS runs come from the NCEP Eta model on a 40-km grid. Verification statistics are generated at land surface observation sites and buoys, and the impacts of the high-resolution lower boundary data on the development and evolution of mesoscale circulations such as sea and land breezes are examined, This paper will present the results of these WRF modeling experiments using LIS and MODIS lower boundary datasets over the Florida peninsula during May 2004.

Sources of variation in plasma corticosterone and dehydroepiandrosterone in the male northern cardinal (Cardinalis cardinalis): II. Effects of urbanization, food supplementation and social stress.

PubMed

Wright, Sarah; Fokidis, H Bobby

2016-09-01

Perturbations in an organism's environment can induce significant shifts in hormone secretory patterns. In this context, the glucocorticoid (GC) steroids secreted by the adrenal cortex have received much attention from ecologists and behaviorists due to their role in the vertebrate stress response. Adrenal GCs, such as corticosterone (CORT), are highly responsive to instability in environmental and social conditions. However, little is understood about how adrenal dehydroepiandrosterone (DHEA) is influenced by changing conditions. We conducted field experiments to determine how circulating CORT and DHEA vary during restraint stress in the male northern cardinals (Cardinalis cardinalis). Specifically, we examined how four different changes in the physical (urbanization and food availability) and social (territorial conflict, distress of a mate) environment affect CORT and DHEA levels. The majority of cardinals responded to restraint stress by increasing and decreasing CORT and DHEA, respectively, however this depended on sampling context. Cardinals sampled from urban habitats had both lower initial and restraint stress CORT concentrations, but a comparable DHEA pattern to those sampled from a forest. Supplementing food to territorial males did not alter circulating initial DHEA or CORT concentrations nor did it change the response to restraint stress when compared to unsupplemented controls. Exposing cardinals to varying durations of song playback, which mimics a territorial intrusion, did not affect CORT levels, but did attenuate the DHEA response to restraint stress. Examining a larger dataset of males captured before, after or at the same time as their female mate, allowed us to address how the stress of a captured mate affected the male's CORT and DHEA response. Males showed elevated initial and restraint CORT and DHEA when their female mate was captured first. Taken together, these data demonstrate that both CORT and DHEA secretion patterns depends on environmental, and particularly current social conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Aspect of ECMWF downscaled Regional Climate Modeling in simulating Indian summer monsoon rainfall and dependencies on lateral boundary conditions

NASA Astrophysics Data System (ADS)

Ghosh, Soumik; Bhatla, R.; Mall, R. K.; Srivastava, Prashant K.; Sahai, A. K.

2018-03-01

Climate model faces considerable difficulties in simulating the rainfall characteristics of southwest summer monsoon. In this study, the dynamical downscaling of European Centre for Medium-Range Weather Forecast's (ECMWF's) ERA-Interim (EIN15) has been utilized for the simulation of Indian summer monsoon (ISM) through the Regional Climate Model version 4.3 (RegCM-4.3) over the South Asia Co-Ordinated Regional Climate Downscaling EXperiment (CORDEX) domain. The complexities of model simulation over a particular terrain are generally influenced by factors such as complex topography, coastal boundary, and lack of unbiased initial and lateral boundary conditions. In order to overcome some of these limitations, the RegCM-4.3 is employed for simulating the rainfall characteristics over the complex topographical conditions. For reliable rainfall simulation, implementations of numerous lower boundary conditions are forced in the RegCM-4.3 with specific horizontal grid resolution of 50 km over South Asia CORDEX domain. The analysis is considered for 30 years of climatological simulation of rainfall, outgoing longwave radiation (OLR), mean sea level pressure (MSLP), and wind with different vertical levels over the specified region. The dependency of model simulation with the forcing of EIN15 initial and lateral boundary conditions is used to understand the impact of simulated rainfall characteristics during different phases of summer monsoon. The results obtained from this study are used to evaluate the activity of initial conditions of zonal wind circulation speed, which causes an increase in the uncertainty of regional model output over the region under investigation. Further, the results showed that the EIN15 zonal wind circulation lacks sufficient speed over the specified region in a particular time, which was carried forward by the RegCM output and leads to a disrupted regional simulation in the climate model.

The prehistory of biology preprints: A forgotten experiment from the 1960s.

PubMed

Cobb, Matthew

2017-11-01

In 1961, the National Institutes of Health (NIH) began to circulate biological preprints in a forgotten experiment called the Information Exchange Groups (IEGs). This system eventually attracted over 3,600 participants and saw the production of over 2,500 different documents, but by 1967, it was effectively shut down following the refusal of journals to accept articles that had been circulated as preprints. This article charts the rise and fall of the IEGs and explores the parallels with the 1990s and the biomedical preprint movement of today.

Use of minimal invasive extracorporeal circulation in cardiac surgery: principles, definitions and potential benefits. A position paper from the Minimal invasive Extra-Corporeal Technologies international Society (MiECTiS)

PubMed Central

Anastasiadis, Kyriakos; Murkin, John; Antonitsis, Polychronis; Bauer, Adrian; Ranucci, Marco; Gygax, Erich; Schaarschmidt, Jan; Fromes, Yves; Philipp, Alois; Eberle, Balthasar; Punjabi, Prakash; Argiriadou, Helena; Kadner, Alexander; Jenni, Hansjoerg; Albrecht, Guenter; van Boven, Wim; Liebold, Andreas; de Somer, Fillip; Hausmann, Harald; Deliopoulos, Apostolos; El-Essawi, Aschraf; Mazzei, Valerio; Biancari, Fausto; Fernandez, Adam; Weerwind, Patrick; Puehler, Thomas; Serrick, Cyril; Waanders, Frans; Gunaydin, Serdar; Ohri, Sunil; Gummert, Jan; Angelini, Gianni; Falk, Volkmar; Carrel, Thierry

2016-01-01

Minimal invasive extracorporeal circulation (MiECC) systems have initiated important efforts within science and technology to further improve the biocompatibility of cardiopulmonary bypass components to minimize the adverse effects and improve end-organ protection. The Minimal invasive Extra-Corporeal Technologies international Society was founded to create an international forum for the exchange of ideas on clinical application and research of minimal invasive extracorporeal circulation technology. The present work is a consensus document developed to standardize the terminology and the definition of minimal invasive extracorporeal circulation technology as well as to provide recommendations for the clinical practice. The goal of this manuscript is to promote the use of MiECC systems into clinical practice as a multidisciplinary strategy involving cardiac surgeons, anaesthesiologists and perfusionists. PMID:26819269

Modern embalming, circulation of fluids, and the voyage through the human arterial system: Carl L. Barnes and the culture of immortality in America.

PubMed

Podgorny, Irina

2011-01-01

By considering the work of American embalmer, lawyer, and physician Carl Lewis Barnes (1872-1927), this paper analyzes the emergence of modern embalming in America. Barnes experimented with and exhibited the techniques by which embalming fluids travelled into the most remote cavities of the human body. In this sense, modem embalmers based their skills and methods on experimental medicine, turning the anatomy of blood vessels, physiology of circulation, and composition of blood into a circuit that allowed embalming fluids to move throughout the corpse. Embalmers in the late 19th century took ownership of the laws of hydrodynamics and the physiology of blood circulation to market their fluids and equipment, thus playing the role of physiologists of death, performing and demonstrating physiological experiments with dead bodies.

Sensitivity of Middle Atmospheric Temperature and Circulation in the UIUC Mesosphere-Stratosphere-Troposphere GCM to the Treatment of Subgrid-Scale Gravity-Wave Breaking

NASA Technical Reports Server (NTRS)

Yang, Fanglin; Schlesinger, Michael E.; Andranova, Natasha; Zubov, Vladimir A.; Rozanov, Eugene V.; Callis, Lin B.

2003-01-01

The sensitivity of the middle atmospheric temperature and circulation to the treatment of mean- flow forcing due to breaking gravity waves was investigated using the University of Illinois at Urbana-Champaign 40-layer Mesosphere-Stratosphere-Troposphere General Circulation Model (MST-GCM). Three GCM experiments were performed. The gravity-wave forcing was represented first by Rayleigh friction, and then by the Alexander and Dunkerton (AD) parameterization with weak and strong breaking effects of gravity waves. In all experiments, the Palmer et al. parameterization was included to treat the breaking of topographic gravity waves in the troposphere and lower stratosphere. Overall, the experiment with the strong breaking effect simulates best the middle atmospheric temperature and circulation. With Rayleigh friction and the weak breaking effect, a large warm bias of up to 60 C was found in the summer upper mesosphere and lower thermosphere. This warm bias was linked to the inability of the GCM to simulate the reversal of the zonal winds from easterly to westerly crossing the mesopause in the summer hemisphere. With the strong breaking effect, the GCM was able to simulate this reversal, and essentially eliminated the warm bias. This improvement was the result of a much stronger meridional transport circulation that possesses a strong vertical ascending branch in the summer upper mesosphere, and hence large adiabatic cooling. Budget analysis indicates that 'in the middle atmosphere the forces that act to maintain a steady zonal-mean zonal wind are primarily those associated with the meridional transport circulation and breaking gravity waves. Contributions from the interaction of the model-resolved eddies with the mean flow are small. To obtain a transport circulation in the mesosphere of the UIUC MST-GCM that is strong enough to produce the observed cold summer mesopause, gravity-wave forcing larger than 100 m/s/day in magnitude is required near the summer mesopause. In the tropics, only with the AD parameterization can the model produce realistic semiannual oscillations.

Hydrothermal Circulation Within and Between Basement Outcrops on a Young Ridge Flank: Numerical Models and Thermal Constraints

NASA Astrophysics Data System (ADS)

Hutnak, M.; Fisher, A. T.; Stauffer, P.; Gable, C. W.

2005-12-01

We use two-dimensional, finite-element models of coupled heat and fluid flow to investigate local and large-scale heat and fluid transport around and between basement outcrops on a young ridge flank. System geometries and properties are based on observations and measurements on the 3.4-3.6 Ma eastern flank of the Juan de Fuca Ridge. A small area of basement exposure (Baby Bare outcrop) experiences focused hydrothermal discharge, whereas a much larger feature (Grizzly Bare outcrop) 50 km to the south is a site of hydrothermal recharge. Observations of seafloor heat flow, subseafloor pressures, and basement fluid geochemistry at and near these outcrops constrain acceptable model results. Single-outcrop simulations suggest that local convection alone (represented by a high Nusselt number proxy) cannot explain the near-outcrop heat flow patterns; rapid through-flow is required. Venting of at least 5 L/s through the smaller outcrop, a volumetric flow rate consistent with earlier estimates based on plume and outcrop measurements, is needed to match seafloor heat flow patterns. Heat flow patterns are more variable and complex near the larger, recharging outcrop. Simulations that include 5-20 L/s of recharge through this feature can replicate first-order trends in the data, but small-scale variations are likely to result from heterogeneous flow paths and vigorous, local convection. Two-outcrop simulations started with a warm hydrostatic initial condition, based on a conductive model, result in rapid fluid flow from the smaller outcrop to the larger outcrop, inconsistent with observations. Flow can be sustained in the opposite (correct) direction if it is initially forced, which generates a hydrothermal siphon between the two features. Free flow simulations maintain rapid circulation at rates consistent with observations (specific discharge of m/yr to tens of m/yr), provided basement permeability is on the order of 10-10 m2 or greater. Lateral flow rates scale inversely with the thickness of the permeable basement layer. The differential pressure needed to drive this circulation, created by the siphon, is on the order of tens to hundreds of kPa, with greater differential pressure needed when basement permeability is lower.

Effects of captopril on the human foetal placental circulation: an interaction with bradykinin and angiotensin I.

PubMed Central

de Moura, R; Lopes, M A

1995-01-01

1. The mechanism underlying the foetal toxicity induced by captopril is not well understood. Since bradykinin and angiotensin II appear to be important in the regulation of the placental circulation, experiments were performed to assess the effects of captopril on the vascular actions of these peptides on the human foetal placental circulation. 2. Full-term human placentas, obtained from normal pregnancy, were perfused with a modified Tyrode solution bubbled with O2 using a pulsatile pump. The placental perfusion pressure was measured with a Statham pressure transducer and recorded continuously on a Hewlett-Packard polygraph. 3. Bradykinin (0.1, 0.3 and 1.0 nmol) injected into the placental arterial circulation produced an increase in placental perfusion pressure in all experiments. This effect of bradykinin was significantly inhibited by indomethacin (3 x 10(-7) M). 4. Captopril (10(-7) M) significantly potentiated the pressor effect of bradykinin on the human placental circulation (n = 6). This effect of captopril was reversed by indomethacin (3 x 10(-7) M). 5. Angiotensin I (n = 6) and angiotensin II (n = 6), injected into the placental arterial circulation, both produced dose-dependent increases in placental perfusion pressure. The dose-response curves to angiotensin I (n = 6) were significantly displaced to the right by captopril in a concentration-dependent manner. 6. We suggest that the toxic effects of captopril on the foetus, rather than reflecting an inhibition of angiotensin II formation, may instead be related to a potentiation of the vasoconstrictor effect of bradykinin on the foetal placental circulation, thereby reducing blood flow and causing foetal damage. The reasons for this are discussed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7669485

Geothermal heating enhances atmospheric asymmetries on synchronously rotating planets

NASA Astrophysics Data System (ADS)

Haqq-Misra, Jacob; Kopparapu, Ravi Kumar

2015-01-01

Earth-like planets within the liquid water habitable zone of M-type stars may evolve into synchronous rotators. On these planets, the substellar hemisphere experiences perpetual daylight while the opposing antistellar hemisphere experiences perpetual darkness. Because the night-side hemisphere has no direct source of energy, the air over this side of the planet is prone to freeze out and deposit on the surface, which could result in atmospheric collapse. However, general circulation models (GCMs) have shown that atmospheric dynamics can counteract this problem and provide sufficient energy transport to the antistellar side. Here, we use an idealized GCM to consider the impact of geothermal heating on the habitability of synchronously rotating planets. Geothermal heating may be expected due to tidal interactions with the host star, and the effects of geothermal heating provide additional habitable surface area and may help to induce melting of ice on the antistellar hemisphere. We also explore the persistence of atmospheric asymmetries between the Northern and Southern hemispheres, and we find that the direction of the meridional circulation (for rapidly rotating planets) or the direction of zonal wind (for slowly rotating planets) reverses on either side of the substellar point. We show that the zonal circulation approaches a theoretical state similar to a Walker circulation only for slowly rotating planets, while rapidly rotating planets show a zonal circulation with the opposite direction. We find that a cross-polar circulation is present in all cases and provides an additional mechanism of mass and energy transport from the substellar to antistellar point. Characterization of the atmospheres of synchronously rotating planets should include consideration of hemispheric differences in meridional circulation and examination of transport due to cross-polar flow.

Meridional overturning and large-scale circulation of the Indian Ocean

NASA Astrophysics Data System (ADS)

Ganachaud, Alexandre; Wunsch, Carl; Marotzke, Jochem; Toole, John

2000-11-01

The large scale Indian Ocean circulation is estimated from a global hydrographic inverse geostrophic box model with a focus on the meridional overturning circulation (MOC). The global model is based on selected recent World Ocean Circulation Experiment (WOCE) sections which in the Indian Basin consist of zonal sections at 32°S, 20°S and 8°S, and a section between Bali and Australia from the Java-Australia Dynamic Experiment (JADE). The circulation is required to conserve mass, salinity, heat, silica and "PO" (170PO4+O2). Near-conservation is imposed within layers bounded by neutral surfaces, while permitting advective and diffusive exchanges between the layers. Conceptually, the derived circulation is an estimate of the average circulation for the period 1987-1995. A deep inflow into the Indian Basin of 11±4 Sv is found, which is in the lower range of previous estimates, but consistent with conservation requirements and the global data set. The Indonesian Throughflow (ITF) is estimated at 15±5 Sv. The flow in the Mozambique Channel is of the same magnitude, implying a weak net flow between Madagascar and Australia. A net evaporation of -0.6±0.4 Sv is found between 32°S and 8°S, consistent with independent estimates. No net heat gain is found over the Indian Basin (0.1 ± 0.2PW north of 32°S) as a consequence of the large warm water influx from the ITF. Through the use of anomaly equations, the average dianeutral upwelling and diffusion between the sections are required and resolved, with values in the range 1-3×10-5 cm s-1 for the upwelling and 2-10 cm2 s-1 for the diffusivity.

Circulation in the South China Sea during summer 2000 as obtained from observations and a generalized topography-following ocean model

NASA Astrophysics Data System (ADS)

Wang, Huiqun; Yuan, Yaochu; Guan, Weibing; Lou, Ruyun; Wang, Kangshan

2004-07-01

On the basis of the recently obtained hydrographic data in the South China Sea, the improved Princeton Ocean Model with a generalized topography-following coordinate system is used to study the circulation in the region during summer 2000. Several sensitivity experiments are carried out to achieve reasonable model parameters for the South China Sea (SCS). It is shown from the resting stratification experiments that the generalized topography-following coordinate scheme is better than the standard sigma grid scheme for reducing the pressure gradient errors. The combination of sea surface height anomaly derived from TOPEX/Poseidon and numerical results with both diagnostic and semidiagnostic simulations provides a consistent circulation pattern for the SCS in August, and the main circulation features can be summarized as follows: (1) There is a notable anticyclonic warm eddy southeast of Vietnam with a horizontal scale of ˜300 km, and there is a cyclonic cold eddy. The simultaneous existence of these cold and warm eddies is one of the important circulation characteristics in the SCS during summer 2000. (2) A secondary cold eddy is found east of Vietnam. (3) The northwestern part of the SCS is dominated by an anticyclonic circulation system. (4) There is also a secondary warm eddy southwest off the Luzon Island. (5) A cyclonic eddy is found west off the Borneo Island. (6) A western intensification phenomenon obviously occurs in the SCS. The dynamical mechanisms of the above-mentioned circulation pattern in the SCS are the interaction between the wind stress and bottom topography and the joint effect of baroclinicity and relief.

Vertical length scale selection for pancake vortices in strongly stratified viscous fluids

NASA Astrophysics Data System (ADS)

Godoy-Diana, Ramiro; Chomaz, Jean-Marc; Billant, Paul

2004-04-01

The evolution of pancake dipoles of different aspect ratio is studied in a stratified tank experiment. Two cases are reported here for values of the dipole initial aspect ratio alpha_0 = L_v/L_h (where L_v and L_h are vertical and horizontal length scales, respectively) of alpha_0 = 0.4 (case I) and alpha_0 = 1.2 (case II). In the first case, the usual decay scenario is observed where the dipole diffuses slowly with a growing thickness and a decaying circulation. In case II, we observed a regime where the thickness of the dipole decreases and the circulation in the horizontal mid-plane of the vortices remains constant. We show that this regime where the vertical length scale decreases can be explained by the shedding of two boundary layers at the top and bottom of the dipole that literally peel off vorticity layers. Horizontal advection and vertical diffusion cooperate in this regime and the decrease towards the viscous vertical length scale delta = L_hRe(-1/2) occurs on a time scale alpha_0 Re(1/2) T_A, T_A being the advection time L_h/U. From a scaling analysis of the equations for a stratified viscous fluid in the Boussinesq approximation, two dominant balances depending on the parameter R = ReF_h(2) are discussed, where F_h = U/NL_h is the horizontal Froude number and Re = UL_h/nu is the Reynolds number, U, N and nu being, respectively, the translation speed of the dipole, the Brunt Väisälä frequency and the kinematic viscosity. When R≫ 1 the vertical length scale is determined by buoyancy effects to be of order L_b = U/N. The experiments presented in this paper pertain to the case of small R, where viscous effects govern the selection of the vertical length scale. We show that if initially L_v ≤ delta, the flow diffuses on the vertical (case I), while if L_v ≫ delta (case II), vertically sheared horizontal advection decreases the vertical length scale down to delta. This viscous regime may explain results from experiments and numerical simulations on the late evolution of stratified flows where the decay is observed to be independent of the buoyancy frequency N.

A global numerical study of radon-222 and lead-210 in the atmosphere using the AES and York University CDT General Circulation Model (AYCG)

NASA Technical Reports Server (NTRS)

Beagley, Stephen R.; Degrandpre, Jean; Mcconnell, John C.; Laprise, Rene; Mcfarlane, Norman

1994-01-01

The Canadian Climate Center (CCC) GCM has been modified to allow its use for studies in atmospheric chemistry. The initial experiments reported here have been run to test and allow sensitivity studies of the new transport module. The impact of different types of parameterization for the convective mixing have been studied based on the large scale evolution of Rn-222 and Pb-210. Preliminary results have shown that the use of a scheme, which mixes unstable columns over a very short time scale, produces a global distribution of lead that agrees in some aspects with observations. The local impact of different mixing schemes on a short lived tracer like the radon is very important.

Initialization, Prediction and Diagnosis of the Rapid Intensification of Tropical Cyclones using the Australian Community Climate and Earth System Simulator, ACCESS

DTIC Science & Technology

2012-10-12

structure on the evolving storm behaviour. 13 7. Large scale influences on Rapid Intensification and Extratropical Transition: RI and ET...assimilation techniques to better initialize and validate TC structures (including the intense inner core and storm asymmetries) consistent with the large...Without vortex specification, initial conditions usually contain a weak and misplaced circulation. Based on estimates of central pressure and storm size

Timeslice experiments for understanding regional climate projections: applications to the tropical hydrological cycle and European winter circulation

NASA Astrophysics Data System (ADS)

Chadwick, Robin; Douville, Hervé; Skinner, Christopher B.

2017-11-01

A set of atmosphere-only timeslice experiments are described, designed to examine the processes that cause regional climate change and inter-model uncertainty in coupled climate model responses to CO_2 forcing. The timeslice experiments are able to reproduce the pattern of regional climate change in the coupled models, and are applied here to two cases where inter-model uncertainty in future projections is large: the tropical hydrological cycle, and European winter circulation. In tropical forest regions, the plant physiological effect is the largest cause of hydrological cycle change in the two models that represent this process. This suggests that the CMIP5 ensemble mean may be underestimating the magnitude of water cycle change in these regions, due to the inclusion of models without the plant effect. SST pattern change is the dominant cause of precipitation and circulation change over the tropical oceans, and also appears to contribute to inter-model uncertainty in precipitation change over tropical land regions. Over Europe and the North Atlantic, uniform SST increases drive a poleward shift of the storm-track. However this does not consistently translate into an overall polewards storm-track shift, due to large circulation responses to SST pattern change, which varies across the models. Coupled model SST biases influence regional rainfall projections in regions such as the Maritime Continent, and so projections in these regions should be treated with caution.

The Sensitivity of Atlantic Meridional Overturning Circulation to Dynamical Framework in an Ocean General Circulation Model

NASA Astrophysics Data System (ADS)

Li, X.; Yu, Y.

2016-12-01

The horizontal coordinate systems commonly used in most global ocean models are the sphere latitude-longitude grid and displaced poles such as tripolar grid. The effect of the horizontal coordinate system on Atlantic Meridional Overturning Circulation (AMOC) is evaluated using an oceanic general circulation model (OGCM). Two experiments are conducted with the model using latitude-longitude grid (Lat_1) and tripolar grid (Tri). Results show that Tri simulates a stronger NADW than Lat_1, as more saline water masses enter into the GIN Seas in Tri. Two reasons can be attributed to the stronger NADW. One is the removal of zonal filter in Tri, which leads to an increasing of zonal gradient of temperature and salinity, thus strengthens the north geostrophic flow. In turn, it decreases the positive subsurface temperature and salinity biases in the subtropical regions. The other may be associated with topography at the North Pole, because the realistic topography is applied in tripolar grid and the longitude-latitude grid employs an artificial island around the North Pole. In order to evaluate the effect of filter on AMOC, three enhanced filter experiments are carried out. Compared to Lat_1, enhanced filter can also increase the NADW, for more saline water is suppressed to go north and accumulated in the Labrador Sea, especially in the experiment with enhanced filter on salinity (Lat_2_S).

[Laboratory evaluation of remediation of nitrobenzene contaminated aquifer by using groundwater circulation well].

PubMed

Bai, Jing; Zhao, Yong-Sheng; Sun, Chao; Qin, Chuan-Yu; Yu, Ling

2014-10-01

A two-dimension simulated sand box was set up to investigate the influencing factors, such as the initial groundwater level, aeration rate and the initial groundwater rate, that affect groundwater circulation well (GCW) by determining the intensity of groundwater circulation which was characterized by the variation of groundwater level before and after aeration. The optimal operating parameters were used to remediate nitrobenzene contaminated aquifer. The results demonstrated that: GCW could be well operated under the conditions of 45 cm groundwater level, 0.7 m3 · h(-1) aeration rate. The effects of groundwater velocity less than 1.0 m · d(-1) could be ignored. The lateral mobility rate of nitrobenzene was faster than that of longitudinal. The average concentration of nitrobenzene was 246.97 mg · L(-1) on day 50 of leakage. During the remediation of circulation well, an efficient organics remediation region was gradually formed around the circulation well. The organics in this region was removed preferentially, and the concentration decreased continuously. Besides the efficient remediation region, there was a transient region, where the concentration of organics was influenced by the combined effects of adsorption/desorption and migration potential of organics. During the whole remediation process, the concentration of nitrobenzene went through three stages described as rapid removal, slow removal. After 14h aeration, the nitrobenzene average concentration was reduced to 71.19 mg L(-1). The residual nitrobenzene was distributed in regions far away from GCW. Therefore, nitrobenzene contaminated aquifer could be well remediated by GCW, and there were optimal operation conditions and appropriate remediation time which guaranteed the best remediation effect.

Two Years After the Schmallenberg Virus Epidemic in the Netherlands: Does the Virus still Circulate?

PubMed

Veldhuis, A M B; Mars, M H; Roos, C A J; van Wuyckhuise, L; van Schaik, G

2017-02-01

Two years after the introduction of the Schmallenberg virus in north-western Europe, it is unknown whether the virus is still circulating in countries that were the first to be confronted with it. When the population-level immunity declines in Europe, reintroduction or the re-emergence of SBV in Europe might eventually result in an outbreak of similar magnitude of that seen in 2011-2012. The Netherlands was part of the primary outbreak region of SBV in 2011. The aim of this study was to determine whether SBV circulated amongst dairy herds in the Netherlands in 2013, and if so, to which extent. For this purpose, the presence of SBV-specific antibodies in naive cattle was investigated. A total of 394 dairy farms were sampled between October and December 2013 by collecting five serum samples per herd. Antibodies were detected in 1.1% [95% confidence interval (CI): 0.7-1.7)] of the animals. All seropositive animals were single reactors per herd and were at least 8 months old at sampling. As these results were inconclusive in demonstrating freedom of SBV circulation, a more in-depth investigation was initiated to provide more insight: an additional sample of 20 youngstock within the same age category (including the five initially sampled animals) was collected from 17 of the 21 positive herds and tested for SBV-specific antibodies. This resulted in 9 antibody-positive test results of 316 samples. Again, the positive samples were single reactors within the sample obtained from each farm, which is unlikely given the characteristics of SBV. Therefore, assuming the single reactors as false-positive, this survey showed with 95% confidence that the maximum possible prevalence of herds with SBV circulation in the Netherlands was <1% in 2013. © 2015 Blackwell Verlag GmbH.

Influence of glacial ice sheets on the Atlantic meridional overturning circulation through surface wind change

NASA Astrophysics Data System (ADS)

Sherriff-Tadano, Sam; Abe-Ouchi, Ayako; Yoshimori, Masakazu; Oka, Akira; Chan, Wing-Le

2018-04-01

Coupled modeling studies have recently shown that the existence of the glacial ice sheets intensifies the Atlantic meridional overturning circulation (AMOC). However, most models show a strong AMOC in their simulations of the Last Glacial Maximum (LGM), which is biased compared to reconstructions that indicate both a weaker and stronger AMOC during the LGM. Therefore, a detailed investigation of the mechanism behind this intensification of the AMOC is important for a better understanding of the glacial climate and the LGM AMOC. Here, various numerical simulations are conducted to focus on the effect of wind changes due to glacial ice sheets on the AMOC and the crucial region where the wind modifies the AMOC. First, from atmospheric general circulation model experiments, the effect of glacial ice sheets on the surface wind is evaluated. Second, from ocean general circulation model experiments, the influence of the wind stress change on the AMOC is evaluated by applying wind stress anomalies regionally or at different magnitudes as a boundary condition. These experiments demonstrate that glacial ice sheets intensify the AMOC through an increase in the wind stress at the North Atlantic mid-latitudes, which is induced by the North American ice sheet. This intensification of the AMOC is caused by the increased oceanic horizontal and vertical transport of salt, while the change in sea ice transport has an opposite, though minor, effect. Experiments further show that the Eurasian ice sheet intensifies the AMOC by directly affecting the deep-water formation in the Norwegian Sea.

Sensitivity of Atlantic meridional overturning circulation to the dynamical framework in an ocean general circulation model

NASA Astrophysics Data System (ADS)

Li, Xiaolan; Yu, Yongqiang; Liu, Hailong; Lin, Pengfei

2017-06-01

The horizontal coordinate systems commonly used in most global ocean models are the spherical latitude-longitude grid and displaced poles, such as a tripolar grid. The effect of the horizontal coordinate system on Atlantic meridional overturning circulation (AMOC) is evaluated by using an OGCM (ocean general circulation model). Two experiments are conducted with the model—one using a latitude-longitude grid (referred to as Lat_1) and the other using a tripolar grid (referred to as Tri). The results show that Tri simulates a stronger North Atlantic deep water (NADW) than Lat_1, as more saline water masses enter the Greenland-Iceland-Norwegian (GIN) seas in Tri. The stronger NADW can be attributed to two factors. One is the removal of the zonal filter in Tri, which leads to an increasing of the zonal gradient of temperature and salinity, thus strengthening the north geostrophic flow. In turn, it decreases the positive subsurface temperature and salinity biases in the subtropical regions. The other may be associated with topography at the North Pole, because realistic topography is applied in the tripolar grid while the latitude-longitude grid employs an artificial island around the North Pole. In order to evaluate the effect of the filter on AMOC, three enhanced filter experiments are carried out. Compared to Lat_1, an enhanced filter can also augment NADW formation, since more saline water is suppressed in the GIN seas, but accumulated in the Labrador Sea, especially in experiment Lat_2_S, which is the experiment with an enhanced filter on salinity.

Benchmarking in a differentially heated rotating annulus experiment: Multiple equilibria in the light of laboratory experiments and simulations

NASA Astrophysics Data System (ADS)

Vincze, Miklos; Harlander, Uwe; Borchert, Sebastian; Achatz, Ulrich; Baumann, Martin; Egbers, Christoph; Fröhlich, Jochen; Hertel, Claudia; Heuveline, Vincent; Hickel, Stefan; von Larcher, Thomas; Remmler, Sebastian

2014-05-01

In the framework of the German Science Foundation's (DFG) priority program 'MetStröm' various laboratory experiments have been carried out in a differentially heated rotating annulus configuration in order to test, validate and tune numerical methods to be used for modeling large-scale atmospheric processes. This classic experimental set-up is well known since the late 1940s and is a widely studied minimal model of the general mid-latitude atmospheric circulation. The two most relevant factors of cyclogenesis, namely rotation and meridional temperature gradient are quite well captured in this simple arrangement. The tabletop-size rotating tank is divided into three sections by coaxial cylindrical sidewalls. The innermost section is cooled whereas the outermost annular cavity is heated, therefore the working fluid (de-ionized water) in the middle annular section experiences differential heat flow, which imposes thermal (density) stratification on the fluid. At high enough rotation rates the isothermal surfaces tilt, leading to baroclinic instability. The extra potential energy stored in this unstable configuration is then converted into kinetic energy, exciting drifting wave patterns of temperature and momentum anomalies. The signatures of these baroclinic waves at the free water surface have been analysed via infrared thermography in a wide range of rotation rates (keeping the radial temperature difference constant) and under different initial conditions (namely, initial spin-up and "spin-down"). Paralelly to the laboratory simulations of BTU Cottbus-Senftenberg, five other groups from the MetStröm collaboration have conducted simulations in the same parameter regime using different numerical approaches and solvers, and applying different initial conditions and perturbations for stability analysis. The obtained baroclinic wave patterns have been evaluated via determining and comparing their Empirical Orthogonal Functions (EOFs), drift rates and dominant wave modes. Thus certain "benchmarks" have been created that can later be used as test cases for atmospheric numerical model validation. Both in the experiments and in the numerics multiple equilibrium states have been observed in the form of hysteretic behavior depending on the initial conditions. The precise quantification of these state and wave mode transitions may shed light to some aspects of the basic underlying dynamics of the baroclinic annulus configuration, still to be understood.

Maintenance of Summer Monsoon Circulations: A Planetary-Scale Perspective.

NASA Astrophysics Data System (ADS)

Chen, Tsing-Chang

2003-06-01

The monsoon circulation, which is generally considered to be driven by the landmass-ocean thermal contrast, like a gigantic land-sea breeze circulation, exhibits a phase reversal in its vertical structure; a monsoon high aloft over a continental thermal low is juxtaposed with a midoceanic trough underlaid by an oceanic anticyclone. This classic monsoon circulation model is well matched by the monsoon circulation depicted with the observational data prior to the First Global Atmospheric Research Program (GARP) Global Experiment (FGGE). However, synthesizing findings of the global circulation portrayed with the post-FGGE data, it was found that some basic features of major monsoon circulations in Asia, North America, South America, and Australia differ from those of the classic monsoon circulation model. Therefore, a revision of the classic monsoon theory is suggested. With four different wave regimes selected to fit the horizontal dimensions of these monsoon circulations, basic features common to all four major monsoons are illustrated in terms of diagnostic analyses of the velocity potential maintenance equation (which relates diabatic heating and velocity potential) and the streamfunction budget (which links velocity potential and streamfunction) in these wave regimes. It is shown that a monsoon circulation is actually driven by the east-west differential heating and maintained dynamically by a balance between a vorticity source and advection. This dynamic balance is reflected by a spatial quadrature relationship between the monsoon divergent circulation and the monsoon high (low) at upper (lower) levels.

Changes in ovarian function associated with circulating concentrations of estradiol before a GnRH-induced ovulation in beef cows

USDA-ARS?s Scientific Manuscript database

These studies were conducted to evaluate causes for differences in circulating concentrations of estradiol prior to a GnRH-induced ovulation and to determine if exogenous GnRH administration could alter LH secretion and subsequent follicular estradiol production. Beef cows (Experiment 1; n = 32, Ex...

An Oceanic General Circulation Model (OGCM) investigation of the Red Sea circulation, 1. Exchange between the Red Sea and the Indian Ocean

NASA Astrophysics Data System (ADS)

Sofianos, Sarantis S.; Johns, William E.

2002-11-01

The mechanisms involved in the seasonal exchange between the Red Sea and the Indian Ocean are studied using an Oceanic General Circulation Model (OGCM), namely the Miami Isopycnic Coordinate Ocean Model (MICOM). The model reproduces the basic characteristics of the seasonal circulation observed in the area of the strait of Bab el Mandeb. There is good agreement between model results and available observations on the strength of the exchange and the characteristics of the water masses involved, as well as the seasonal flow pattern. During winter, this flow consists of a typical inverse estuarine circulation, while during summer, the surface flow reverses, there is an intermediate inflow of relatively cold and fresh water, and the hypersaline outflow at the bottom of the strait is significantly reduced. Additional experiments with different atmospheric forcing (seasonal winds, seasonal thermohaline air-sea fluxes, or combinations) were performed in order to assess the role of the atmospheric forcing fields in the exchange flow at Bab el Mandeb. The results of both the wind- and thermohaline-driven experiments exhibit a strong seasonality at the area of the strait, which is in phase with the observations. However, it is the combination of both the seasonal pattern of the wind stress and the seasonal thermohaline forcing that can reproduce the observed seasonal variability at the strait. The importance of the seasonal cycle of the thermohaline forcing on the exchange flow pattern is also emphasized by these results. In the experiment where the thermohaline forcing is represented by its annual mean, the strength of the exchange is reduced almost by half.

Deep sequencing identifies circulating mouse miRNAs that are functionally implicated in manifestations of aging and responsive to calorie restriction.

PubMed

Dhahbi, Joseph M; Spindler, Stephen R; Atamna, Hani; Yamakawa, Amy; Guerrero, Noel; Boffelli, Dario; Mote, Patricia; Martin, David I K

2013-02-01

MicroRNAs (miRNAs) function to modulate gene expression, and through this property they regulate a broad spectrum of cellular processes. They can circulate in blood and thereby mediate cell-to-cell communication. Aging involves changes in many cellular processes that are potentially regulated by miRNAs, and some evidence has implicated circulating miRNAs in the aging process. In order to initiate a comprehensive assessment of the role of circulating miRNAs in aging, we have used deep sequencing to characterize circulating miRNAs in the serum of young mice, old mice, and old mice maintained on calorie restriction (CR). Deep sequencing identifies a set of novel miRNAs, and also accurately measures all known miRNAs present in serum. This analysis demonstrates that the levels of many miRNAs circulating in the mouse are increased with age, and that the increases can be antagonized by CR. The genes targeted by this set of age-modulated miRNAs are predicted to regulate biological processes directly relevant to the manifestations of aging including metabolic changes, and the miRNAs themselves have been linked to diseases associated with old age. This finding implicates circulating miRNAs in the aging process, raising questions about their tissues of origin, their cellular targets, and their functional role in metabolic changes that occur with aging.

Development of a 25 K Pulse Tube Refrigerator for Future HTS-Series Products in Power Engineering

NASA Astrophysics Data System (ADS)

Gromoll, B.; Huber, N.; Dietrich, M.; Yang, L. W.; Thummes, G.

2006-04-01

Demands are made on refrigerators for future HTS-series products like generators, motors, transformers, which are only partly fulfilled by commercially available refrigerators. Based on the experiences with HTS-prototypes, pulse tube refrigerators (PTRs) are considered to have the highest potential to fulfill the identified requirements. Siemens have therefore started the development of a high-performance PTR together with TransMIT Giessen. Design target is a PTR with a cooling power of 80 W near 25 K based on an oil-free CFIC — linear compressor with a power input of 2 × 5 kW. The initial tests on the first single-stage laboratory version of this PTR with stainless steel mesh regenerator revealed high regenerator losses from circulating mass flow that manifests itself in form of an azimuthal temperature asymmetry in the regenerator. The circulating flow can be greatly reduced by increasing the transverse heat conductance of the matrix by use of stacks of different materials. So far, the minimum no-load temperature of the PTR is 35 K and a cooling power of 75 W is available at 50 K with a compressor efficiency of about 80 %. Further optimization of the regenerator matrix appears to be possible.

Equilibrium and kinetic studies of sorption of 2.4-dichlorophenol onto 2 mixtures: bamboo biochar plus calcium sulphate (BC) and hydroxyapatite plus bamboo biochar plus calcium sulphate (HBC), in a fluidized bed circulation column

DOE PAGES

Alamin, Ahmed Hassan; Kaewsichan, Lupong

2016-06-30

Sorption studies were carried out to investigate removal of 2.4-dichlorophenol (2.4-DCP) from aqueous solution in a fluidized bed by two types of adsorbent mixtures: BC (Bamboo char plus Calcium sulphate), and HBC (Hydroxyapatite plus Bamboo char plus Calcium sulphate); both manufactured in ball shape. The main material bamboo char was characterized by FTIR, DTA and SEM. The adsorption experiments were conducted in a fluidized bed circulation column. Adsorption, isotherms and kinetic studies were established under 180 min operating process time, at different initial 2.4-DCP solution concentrations ranging from 5–10 mg/L, and at different flow rates ranging from 0.25–0.75 L/min. Themore » data obtained fitted well for both the Langmuir and Freundlich isotherm models; indicating favorable condition of monolayer adsorption. The kinetics of both adsorbents complies with the pseudo second-order kinetic model. BC was proven a new effective composite and low cost adsorbent which can be applied in the field of wastewater treatment, and it can also play an important role in industry water treatment« less

Equilibrium and kinetic studies of sorption of 2.4-dichlorophenol onto 2 mixtures: bamboo biochar plus calcium sulphate (BC) and hydroxyapatite plus bamboo biochar plus calcium sulphate (HBC), in a fluidized bed circulation column

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alamin, Ahmed Hassan; Kaewsichan, Lupong

Sorption studies were carried out to investigate removal of 2.4-dichlorophenol (2.4-DCP) from aqueous solution in a fluidized bed by two types of adsorbent mixtures: BC (Bamboo char plus Calcium sulphate), and HBC (Hydroxyapatite plus Bamboo char plus Calcium sulphate); both manufactured in ball shape. The main material bamboo char was characterized by FTIR, DTA and SEM. The adsorption experiments were conducted in a fluidized bed circulation column. Adsorption, isotherms and kinetic studies were established under 180 min operating process time, at different initial 2.4-DCP solution concentrations ranging from 5–10 mg/L, and at different flow rates ranging from 0.25–0.75 L/min. Themore » data obtained fitted well for both the Langmuir and Freundlich isotherm models; indicating favorable condition of monolayer adsorption. The kinetics of both adsorbents complies with the pseudo second-order kinetic model. BC was proven a new effective composite and low cost adsorbent which can be applied in the field of wastewater treatment, and it can also play an important role in industry water treatment« less

Droplet-based magnetically activated cell separation: analysis of separation efficiency based on the variation of flow-induced circulation in a pendent drop.

PubMed

Kim, Youngho; Lee, Sang Ho; Kim, Byungkyu

2009-12-01

Under the assumption that separation efficiencies are mainly affected by the velocity of flow-induced circulation due to buffer injection in a pendent drop, this paper describes an analysis of the separation efficiency of a droplet-based magnetically activated cell separation (DMACS) system. To investigate the velocity of the flow-induced circulation, we supposed that numerous flows in a pendent drop could be considered as a "theoretically normalized" flow (or conceptually normalized flow, CNF) based on the Cauchy-Goursat theorem. With the morphological characteristics (length and duration time) of a pendent drop depending on the initial volume, we obtained the velocities of the CNF. By measuring the separation efficiencies for different initial volumes and by analyzing the separation efficiency in terms of the velocity of the CNF, we found that the separation efficiencies (in the case of a low rate of buffer injection; 5 and 15 microl x min(-1)) are mainly affected by the velocity of the CNF. Moreover, we confirmed that the phenomenological features of a pendent drop cause a fluctuation of its separation efficiencies over a range of specific volumes (initial volumes ranging from 40 to 80 microl), because of the "sweeping-off" phenomenon, that is, positive cells gathered into the positive fraction are forced to move away from the magnetic side by flow-induced circulation due to buffer injection. In addition, from the variation of the duration time, that is, the interval between the beginning of injection of the buffer solution and the time at which a pendent drop detaches, it could also be confirmed that a shorter duration time leads to decrease of the number of positive cells in negative fraction regardless of the rate of buffer injection (5, 15, and 50 microl x min(-1)). Therefore, if a DMACS system is operated with a 15 microl x min(-1) buffer injection flow rate and an initial volume of 80 microl or more, we would have the best efficiency of separation in the negative fraction.

Pharmacology Experiments on the Computer.

ERIC Educational Resources Information Center

Keller, Daniel

1990-01-01

A computer program that replaces a set of pharmacology and physiology laboratory experiments on live animals or isolated organs is described and illustrated. Five experiments are simulated: dose-effect relationships on smooth muscle, blood pressure and catecholamines, neuromuscular signal transmission, acetylcholine and the circulation, and…

Evaluating the influence of antecedent soil moisture on variability of the North American Monsoon precipitation in the coupled MM5/VIC modeling system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Chunmei; Leung, Lai R.; Gochis, David

2009-11-29

The influence of antecedent soil moisture on North American monsoon system (NAMS) precipitation variability was explored using the MM5 mesoscale model coupled with the Variable Infiltration Capacity (VIC) land surface model. Sensitivity experiments were performed with extreme wet and dry initial soil moisture conditions for both the 1984 wet monsoon year and the 1989 dry year. The MM5-VIC model reproduced the key features of NAMS in 1984 and 1989 especially over northwestern Mexico. Our modeling results indicate that the land surface has memory of the initial soil wetness prescribed at the onset of the monsoon that persists over most ofmore » the region well into the monsoon season (e.g. until August). However, in contrast to the classical thermal contrast concept, where wetter soils lead to cooler surface temperatures, less land-sea thermal contrast, weaker monsoon circulations and less precipitation, the coupled model consistently demonstrated a positive soil moisture – precipitation feedback. Specifically, anomalously wet premonsoon soil moisture always lead to enhanced monsoon precipitation, and the reverse was also true. The surface temperature changes induced by differences in surface energy flux partitioning associated with pre-monsoon soil moisture anomalies changed the surface pressure and consequently the flow field in the coupled model, which in turn changed moisture convergence and, accordingly, precipitation patterns. Both the largescale circulation change and local land-atmospheric interactions in response to premonsoon soil moisture anomalies play important roles in the coupled model’s positive soil moisture monsoon precipitation feedback. However, the former may be sensitive to the strength and location of the thermal anomalies, thus leaving open the possibility of both positive and negative soil moisture precipitation feedbacks.« less

Impact of cloud radiative heating on East Asian summer monsoon circulation

DOE PAGES

Guo, Zhun; Zhou, Tianjun; Wang, Minghuai; ...

2015-07-17

The impacts of cloud radiative heating on East Asian Summer Monsoon (EASM) over the southeastern China (105°-125°E, 20°-35°N) are explained by using the Community Atmosphere Model version 5 (CAM5). Sensitivity experiments demonstrate that the radiative heating of clouds leads to a positive effect on the local EASM circulation over southeastern China. Without the radiative heating of cloud, the EASM circulation and precipitation would be much weaker than that in the normal condition. The longwave heating of clouds dominates the changes of EASM circulation. The positive effect of clouds on EASM circulation is explained by the thermodynamic energy equation, i.e. themore » different heating rate between cloud base and cloud top enhances the convective instability over southeastern China, which enhances updraft consequently. The strong updraft would further result in a southward meridional wind above the center of the updraft through Sverdrup vorticity balance.« less

Quasi-periodic oscillations in a symmetric general circulation model

NASA Technical Reports Server (NTRS)

Goswami, B. N.; Shukla, J.

1984-01-01

Observational evidence has been presented for the existence of quasi-periodic fluctuations of the tropical circulation with periods around two weeks and around 40 days. It is expected that an understanding of the mechanisms of these quasi-periodic oscillations in the tropical atmosphere will improve the predictability of the short range climate fluctuations in the tropics. The present study evolved as an outgrowth of an investigation conducted by Goswami et al. (1984). In this investigation remarkable oscillations of the Hadlay circulation for an ocean covered earth were observed. In the current study evidence is presented regarding the episodic behavior of the tropical circulation in general, and the propagation characteristics of these oscillations in the lower atmosphere. Attention is given to the results of six different experiments.

Improved Decadal Climate Prediction in the North Atlantic using EnOI-Assimilated Initial Condition

NASA Astrophysics Data System (ADS)

Li, Q.; Xin, X.; Wei, M.; Zhou, W.

2017-12-01

Decadal prediction experiments of Beijing Climate Center climate system model version 1.1(BCC-CSM1.1) participated in Coupled Model Intercomparison Project Phase 5 (CMIP5) had poor skill in extratropics of the North Atlantic, the initialization of which was done by relaxing modeled ocean temperature to the Simple Ocean Data Assimilation (SODA) reanalysis data. This study aims to improve the prediction skill of this model by using the assimilation technique in the initialization. New ocean data are firstly generated by assimilating the sea surface temperature (SST) of the Hadley Centre Sea Ice and Sea Surface Temperature (HadISST) dataset to the ocean model of BCC-CSM1.1 via Ensemble Optimum Interpolation (EnOI). Then a suite of decadal re-forecasts launched annually over the period 1961-2005 is carried out with simulated ocean temperature restored to the assimilated ocean data. Comparisons between the re-forecasts and previous CMIP5 forecasts show that the re-forecasts are more skillful in mid-to-high latitude SST of the North Atlantic. Improved prediction skill is also found for the Atlantic multi-decadal Oscillation (AMO), which is consistent with the better skill of Atlantic meridional overturning circulation (AMOC) predicted by the re-forecasts. We conclude that the EnOI assimilation generates better ocean data than the SODA reanalysis for initializing decadal climate prediction of BCC-CSM1.1 model.

Interaction of the sea breeze with a river breeze in an area of complex coastal heating

NASA Technical Reports Server (NTRS)

Zhong, Shiyuan; Takle, Eugene S.; Leone, John M., Jr.

1991-01-01

The interaction of the sea-breeze circulation with a river-breeze circulation in an area of complex coastal heating (east coast of Florida) was studied using a 3D finite-element mesoscale model. The model simulations are compared with temperature and wind fields observed on a typical fall day during the Kennedy Space Center Atmospheric Boundary Layer Experiment. The results from numerical experiments designed to isolate the effect of the river breeze indicate that the convergence in the sea-breeze front is suppressed when it passes over the cooler surface of the rivers.

Female Hamster Preference for Odors is Not Regulated by Circulating Gonadal Hormones

PubMed Central

Eidson, Lori N.; Maras, Pamela M.; Epperson, Erin; Petrulis, Aras

2009-01-01

Proceptive and receptive behaviors of female rodents, such as golden hamsters, are often regulated by changes in circulating levels of ovarian hormones. However, less is known about how ovarian hormones might regulate female hamster’s attraction and preference for volatile odor from males. To evaluate this, we assessed female preference by recording investigation and proximity to male and female volatile odorants in a Y-maze across all days of the estrous cycle (Experiment 1 & 2) or following ovariectomy (Experiment 3). In Experiment 1, female subjects were tested four times, once on each day of their estrous cycle. Females showed a preference for male odors on diestrus day 1 and to a lesser degree on proestrus, but showed no preference on the day of behavioral estrus. Irrespective of cycle day, preference was apparent in the first few days of testing and disappeared by the fourth day, suggesting that repeated testing attenuated female preference. To avoid this problem, in Experiment 2 each animal was tested only on one day of the 4-day estrous cycle. Female preference for male volatile odors over those from females was observed on each day of their estrous cycle, including estrus. Moreover, following gonadectomy (Experiment 3) female hamsters still preferred male volatile odors to those of females. Taken together, this suggests that circulating levels of gonadal hormones do not influence preference for male volatile odors in female hamsters. PMID:17374544

KSC-03PD-0179

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- After being dropped from the L-1011 aircraft at 3:14 p.m. EST over the Atlantic Ocean, the Pegasus XL rocket fires, propelling NASA's Solar Radiation and Climate Experiment (SORCE) toward its orbit. Separation of the spacecraft from the rocket occurred 10 minutes and 46 seconds after launch at about 3:24 p.m. Initial contact with the satellite was made seven seconds after separation via a NASA communications satellite network. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

Soil Moisture, Coastline Curvature, and Sea Breeze Initiated Precipitation Over Florida

NASA Technical Reports Server (NTRS)

Baker, R. David; Lynn, Barry H.; Boone, Aaron; Tao, Wei-Kuo

1999-01-01

Land surface-atmosphere interaction plays a key role in the development of summertime convection and precipitation over the Florida peninsula. Land-ocean temperature contrasts induce sea-breeze circulations along both coasts. Clouds develop along sea-breeze fronts, and significant precipitation can occur during the summer months. However, other factors such as soil moisture distribution and coastline curvature may modulate the timing, location, and intensity of sea breeze initiated precipitation. Here, we investigate the role of soil moisture and coastline curvature on Florida precipitation using the 3-D Goddard Cumulus Ensemble (GCE) cloud model coupled with the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model. This study utilizes data from the Convection and Precipitation Electrification Experiment (CaPE) collected on 27 July 1991. Our numerical simulations suggest that a realistic distribution of soil moisture influences the location and intensity of precipitation but not the timing of precipitation. In contrast, coastline curvature affects the timing and location of precipitation but has little influence on peak rainfall rates. However, both factors (soil moisture and coastline curvature) are required to fully account for observed rainfall amounts.

KSC-03pd0179

NASA Image and Video Library

2003-01-25

KENNEDY SPACE CENTER, FLA. -- After being dropped from the L-1011 aircraft at 3:14 p.m. EST over the Atlantic Ocean, the Pegasus XL rocket fires, propelling NASA's Solar Radiation and Climate Experiment (SORCE) toward its orbit. Separation of the spacecraft from the rocket occurred 10 minutes and 46 seconds after launch at about 3:24 p.m. Initial contact with the satellite was made seven seconds after separation via a NASA communications satellite network. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

The Mediterranean Overflow in the Gulf of Cadiz: A rugged journey

PubMed Central

Sánchez-Leal, Ricardo F.; Bellanco, María Jesús; Fernández-Salas, Luis Miguel; García-Lafuente, Jesús; Gasser-Rubinat, Marc; González-Pola, César; Hernández-Molina, Francisco J.; Pelegrí, Josep L.; Peliz, Alvaro; Relvas, Paulo; Roque, David; Ruiz-Villarreal, Manuel; Sammartino, Simone; Sánchez-Garrido, José Carlos

2017-01-01

The pathways and transformations of dense water overflows, which depend on small-scale interactions between flow dynamics and erosional-depositional processes, are a central piece in the ocean’s large-scale circulation. A novel, high-resolution current and hydrographic data set highlights the intricate pathway travelled by the saline Mediterranean Overflow as it enters the Atlantic. Interaction with the topography constraints its spreading. Over the initial 200 km west of the Gibraltar gateway, distinct channels separate the initial gravity current into several plunging branches depth-sorted by density. Shallow branches follow the upper slope and eventually detach as buoyant plumes. Deeper branches occupy mid slope channels and coalesce upon reaching a diapiric ridge. A still deeper branch, guided by a lower channel wall marked by transverse furrows, experiences small-scale overflows which travel downslope to settle at mid-depths. The Mediterranean salt flux into the Atlantic has implications for the buoyancy balance in the North Atlantic. Observations on how this flux enters at different depth levels are key to accurately measuring and understanding the role of Mediterranean Outflow in future climate scenarios. PMID:29152570

Self-organization of hydrothermal outflow and recharge in young oceanic crust: Constraints from open-top porous convection analog experiments

NASA Astrophysics Data System (ADS)

Mittelstaedt, E. L.; Olive, J. A. L.; Barreyre, T.

2016-12-01

Hydrothermal circulation at the axis of mid-ocean ridges has a profound effect on chemical and biological processes in the deep ocean, and influences the thermo-mechanical state of young oceanic lithosphere. Yet, the geometry of fluid pathways beneath the seafloor and its relation to spatial gradients in crustal permeability remain enigmatic. Here we present new laboratory models of hydrothermal circulation aimed at constraining the self-organization of porous convection cells in homogeneous as well as highly heterogeneous crust analogs. Oceanic crust analogs of known permeability are constructed using uniform glass spheres and 3-D printed plastics with a network of mutually perpendicular tubes. These materials are saturated with corn syrup-water mixtures and heated at their base by a resistive silicone strip heater to initiate thermal convection. A layer of pure fluid (i.e., an analog ocean) overlies the porous medium and allows an "open-top" boundary condition. Areas of fluid discharge from the crust into the ocean are identified by illuminating microscopic glass particles carried by the fluid, using laser sheets. Using particle image velocimetry, we estimate fluid discharge rates as well as the location and extent of fluid recharge. Thermo-couples distributed throughout the crust provide insights into the geometry of convection cells at depth, and enable estimates of convective heat flux, which can be compared to the heat supplied at the base of the system. Preliminary results indicate that in homogeneous crust, convection is largely confined to the narrow slot overlying the heat source. Regularly spaced discharge zones appear focused while recharge areas appear diffuse, and qualitatively resemble the along-axis distribution of hydrothermal fields at oceanic spreading centers. By varying the permeability of the crustal analogs, the viscosity of the convecting fluid, and the imposed basal temperature, our experiments span Rayleigh numbers between 10 and 10,000. This allows us to precisely map the conditions of convection initiation, and test scaling relations between the Nusselt and Rayleigh numbers. Finally, we investigate how these scalings and convection geometry change when a slot of high-permeability material (i.e., an analog fault) is introduced in the middle of the porous domain.

The effect of latent heat release on synoptic-to-planetary wave interactions and its implication for satellite observations: Theoretical modeling

NASA Technical Reports Server (NTRS)

Branscome, Lee E.; Bleck, Rainer; Obrien, Enda

1990-01-01

The project objectives are to develop process models to investigate the interaction of planetary and synoptic-scale waves including the effects of latent heat release (precipitation), nonlinear dynamics, physical and boundary-layer processes, and large-scale topography; to determine the importance of latent heat release for temporal variability and time-mean behavior of planetary and synoptic-scale waves; to compare the model results with available observations of planetary and synoptic wave variability; and to assess the implications of the results for monitoring precipitation in oceanic-storm tracks by satellite observing systems. Researchers have utilized two different models for this project: a two-level quasi-geostrophic model to study intraseasonal variability, anomalous circulations and the seasonal cycle, and a 10-level, multi-wave primitive equation model to validate the two-level Q-G model and examine effects of convection, surface processes, and spherical geometry. It explicitly resolves several planetary and synoptic waves and includes specific humidity (as a predicted variable), moist convection, and large-scale precipitation. In the past year researchers have concentrated on experiments with the multi-level primitive equation model. The dynamical part of that model is similar to the spectral model used by the National Meteorological Center for medium-range forecasts. The model includes parameterizations of large-scale condensation and moist convection. To test the validity of results regarding the influence of convective precipitation, researchers can use either one of two different convective schemes in the model, a Kuo convective scheme or a modified Arakawa-Schubert scheme which includes downdrafts. By choosing one or the other scheme, they can evaluate the impact of the convective parameterization on the circulation. In the past year researchers performed a variety of initial-value experiments with the primitive-equation model. Using initial conditions typical of climatological winter conditions, they examined the behavior of synoptic and planetary waves growing in moist and dry environments. Surface conditions were representative of a zonally averaged ocean. They found that moist convection associated with baroclinic wave development was confined to the subtropics.

Physics-based coastal current tomographic tracking using a Kalman filter.

PubMed

Wang, Tongchen; Zhang, Ying; Yang, T C; Chen, Huifang; Xu, Wen

2018-05-01

Ocean acoustic tomography can be used based on measurements of two-way travel-time differences between the nodes deployed on the perimeter of the surveying area to invert/map the ocean current inside the area. Data at different times can be related using a Kalman filter, and given an ocean circulation model, one can in principle now cast and even forecast current distribution given an initial distribution and/or the travel-time difference data on the boundary. However, an ocean circulation model requires many inputs (many of them often not available) and is unpractical for estimation of the current field. A simplified form of the discretized Navier-Stokes equation is used to show that the future velocity state is just a weighted spatial average of the current state. These weights could be obtained from an ocean circulation model, but here in a data driven approach, auto-regressive methods are used to obtain the time and space dependent weights from the data. It is shown, based on simulated data, that the current field tracked using a Kalman filter (with an arbitrary initial condition) is more accurate than that estimated by the standard methods where data at different times are treated independently. Real data are also examined.

Hybrid Continuous-Flow Total Artificial Heart.

PubMed

Fox, Carson; Chopski, Steven; Murad, Nohra; Allaire, Paul; Mentzer, Robert; Rossano, Joseph; Arabia, Francisco; Throckmorton, Amy

2018-05-01

Clinical studies using total artificial hearts (TAHs) have demonstrated that pediatric and adult patients derive quality-of-life benefits from this form of therapy. Two clinically-approved TAHs and other pumps under development, however, have design challenges and limitations, including thromboembolic events, neurologic impairment, infection risk due to large size and percutaneous drivelines, and lack of ambulation, to name a few. To address these limitations, we are developing a hybrid-design, continuous-flow, implantable or extracorporeal, magnetically-levitated TAH for pediatric and adult patients with heart failure. This TAH has only two moving parts: an axial impeller for the pulmonary circulation and a centrifugal impeller for the systemic circulation. This device will utilize the latest generation of magnetic bearing technology. Initial geometries were established using pump design equations, and computational modeling provided insight into pump performance. The designs were the basis for prototype manufacturing and hydraulic testing. The study results demonstrate that the TAH is capable of delivering target blood flow rates of 1-6.5 L/min with pressure rises of 1-92 mm Hg for the pulmonary circulation and 24-150 mm Hg for the systemic circulation at 1500-10 000 rpm. This initial design of the TAH was successful and serves as the foundation to continue its development as a novel, more compact, nonthrombogenic, and effective therapeutic alternative for infants, children, adolescents, and adults with heart failure. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

The impact of the ocean observing system on estimates of the California current circulation spanning three decades

NASA Astrophysics Data System (ADS)

Moore, Andrew M.; Jacox, Michael G.; Crawford, William J.; Laughlin, Bruce; Edwards, Christopher A.; Fiechter, Jérôme

2017-08-01

Data assimilation is now used routinely in oceanography on both regional and global scales for computing ocean circulation estimates and for making ocean forecasts. Regional ocean observing systems are also expanding rapidly, and observations from a wide array of different platforms and sensor types are now available. Evaluation of the impact of the observing system on ocean circulation estimates (and forecasts) is therefore of considerable interest to the oceanographic community. In this paper, we quantify the impact of different observing platforms on estimates of the California Current System (CCS) spanning a three decade period (1980-2010). Specifically, we focus attention on several dynamically related aspects of the circulation (coastal upwelling, the transport of the California Current and the California Undercurrent, thermocline depth and eddy kinetic energy) which in many ways describe defining characteristics of the CCS. The circulation estimates were computed using a 4-dimensional variational (4D-Var) data assimilation system, and our analyses also focus on the impact of the different elements of the control vector (i.e. the initial conditions, surface forcing, and open boundary conditions) on the circulation. While the influence of each component of the control vector varies between different metrics of the circulation, the impact of each observing system across metrics is very robust. In addition, the mean amplitude of the circulation increments (i.e. the difference between the analysis and background) remains relatively stable throughout the three decade period despite the addition of new observing platforms whose impact is redistributed according to the relative uncertainty of observations from each platform. We also consider the impact of each observing platform on CCS circulation variability associated with low-frequency climate variability. The low-frequency nature of the dominant climate modes in this region allows us to track through time the impact of each observation on the circulation, and illustrates how observations from some platforms can influence the circulation up to a decade into the future.

Tropical storm interannual and interdecadal variability in an ensemble of GCM integrations

NASA Astrophysics Data System (ADS)

Vitart, Frederic Pol.

1999-11-01

A T42L18 Atmospheric General Circulation Model forced by observed SSTs has been integrated for 10 years with 9 different initial conditions. An objective procedure for tracking model-generated tropical storms has been applied to this ensemble. Statistical tools have been applied to the ensemble frequency, intensity and location of tropical storms, leading to the conclusion that the potential predictability is particularly strong over the western North Pacific, the eastern North Pacific and the western North Atlantic. An EOF analysis of local SSts and a combined EOF analysis of vertical wind shear, 200 mb and 850 mb vorticity indicate that the simulated tropical storm interannual variability is mostly constrained by the large scale circulation as in observations. The model simulates a realistic interannual variability of tropical storms over the western North Atlantic, eastern North Pacific, western North Pacific and Australian basin where the model simulates a realistic large scale circulation. Several experiments with the atmospheric GCM forced by imposed SSTs demonstrate that the GCM simulates a realistic impact of ENSO on the simulated Atlantic tropical storms. In addition the GCM simulates fewer tropical storms over the western North Atlantic with SSTs of the 1950s than with SSTs of the 1970s in agreement with observations. Tropical storms simulated with RAS and with MCA have been compared to evaluate their sensitivity to a change in cumulus parameterization. Composites of tropical storm structure indicate stronger tropical storms with higher warm cores with MCA. An experiment using the GFDL hurricane model and several theoretical calculations indicate that the mean state may be responsible for the difference in intensity and in the height of the warm core. With the RAS scheme, increasing the threshold which determines when convection can occur increases the tropical storm frequency almost linearly. The increase of tropical storm frequency seems to be linked to an increase of CAPE. Tropical storms predicted by a coupled model produce a strong cooling of SSTs and their intensity is lower than in the simulations. An ensemble of coupled GCM integrations displays some skill in forecasting the tropical storm frequency when starting on July 1st.

Kinetics, prognostic and predictive values of ESR1 circulating mutations in metastatic breast cancer patients progressing on aromatase inhibitor

PubMed Central

Clatot, Florian; Perdrix, Anne; Augusto, Laetitia; Beaussire, Ludivine; Delacour, Julien; Calbrix, Céline; Sefrioui, David; Viailly, Pierre-Julien; Bubenheim, Michael; Moldovan, Cristian; Alexandru, Cristina; Tennevet, Isabelle; Rigal, Olivier; Guillemet, Cécile; Leheurteur, Marianne; Gouérant, Sophie; Petrau, Camille; Théry, Jean-Christophe; Picquenot, Jean-Michel; Veyret, Corinne; Frébourg, Thierry; Jardin, Fabrice

2016-01-01

Purpose To assess the prognostic and predictive value of circulating ESR1 mutation and its kinetics before and after progression on aromatase inhibitor (AI) treatment. Patients and methods ESR1 circulating D538G and Y537S/N/C mutations were retrospectively analyzed by digital droplet PCR after first-line AI failure in patients treated consecutively from 2010 to 2012 for hormone receptor-positive metastatic breast cancer. Progression-free survival (PFS) and overall survival (OS) were analyzed according to circulating mutational status and subsequent lines of treatment. The kinetics of ESR1 mutation before (3 and 6 months) and after (3 months) AI progression were determined in the available archive plasmas. Results Circulating ESR1 mutations were found at AI progression in 44/144 patients included (30.6%). Median follow-up from AI initiation was 40 months (range 4-94). The median OS was decreased in patients with circulating ESR1 mutation than in patients without mutation (15.5 versus 23.8 months, P=0.0006). The median PFS was also significantly decreased in patients with ESR1 mutation than in patients without mutation (5.9 vs 7 months, P=0.002). After AI failure, there was no difference in outcome for patients receiving chemotherapy (n = 58) versus non-AI endocrine therapy (n=51) in patients with and without ESR1 mutation. ESR1 circulating mutations were detectable in 75% of all cases before AI progression, whereas the kinetics 3 months after progression did not correlate with outcome. Conclusion ESR1 circulating mutations are independent risk factors for poor outcome after AI failure, and are frequently detectable before clinical progression. Interventional studies based on ESR1 circulating status are warranted. PMID:27801670

Kinetics, prognostic and predictive values of ESR1 circulating mutations in metastatic breast cancer patients progressing on aromatase inhibitor.

PubMed

Clatot, Florian; Perdrix, Anne; Augusto, Laetitia; Beaussire, Ludivine; Delacour, Julien; Calbrix, Céline; Sefrioui, David; Viailly, Pierre-Julien; Bubenheim, Michael; Moldovan, Cristian; Alexandru, Cristina; Tennevet, Isabelle; Rigal, Olivier; Guillemet, Cécile; Leheurteur, Marianne; Gouérant, Sophie; Petrau, Camille; Théry, Jean-Christophe; Picquenot, Jean-Michel; Veyret, Corinne; Frébourg, Thierry; Jardin, Fabrice; Sarafan-Vasseur, Nasrin; Di Fiore, Frédéric

2016-11-15

To assess the prognostic and predictive value of circulating ESR1 mutation and its kinetics before and after progression on aromatase inhibitor (AI) treatment. ESR1 circulating D538G and Y537S/N/C mutations were retrospectively analyzed by digital droplet PCR after first-line AI failure in patients treated consecutively from 2010 to 2012 for hormone receptor-positive metastatic breast cancer. Progression-free survival (PFS) and overall survival (OS) were analyzed according to circulating mutational status and subsequent lines of treatment. The kinetics of ESR1 mutation before (3 and 6 months) and after (3 months) AI progression were determined in the available archive plasmas. Circulating ESR1 mutations were found at AI progression in 44/144 patients included (30.6%). Median follow-up from AI initiation was 40 months (range 4-94). The median OS was decreased in patients with circulating ESR1 mutation than in patients without mutation (15.5 versus 23.8 months, P=0.0006). The median PFS was also significantly decreased in patients with ESR1 mutation than in patients without mutation (5.9 vs 7 months, P=0.002). After AI failure, there was no difference in outcome for patients receiving chemotherapy (n = 58) versus non-AI endocrine therapy (n=51) in patients with and without ESR1 mutation. ESR1 circulating mutations were detectable in 75% of all cases before AI progression, whereas the kinetics 3 months after progression did not correlate with outcome. ESR1 circulating mutations are independent risk factors for poor outcome after AI failure, and are frequently detectable before clinical progression. Interventional studies based on ESR1 circulating status are warranted.

Does coupled ocean enhance ozone-hole-induced Southern Hemisphere circulation changes?

NASA Astrophysics Data System (ADS)

Son, S. W.; Han, B. R.; Kim, S. Y.; Park, R.

2017-12-01

The ozone-hole-induced Southern Hemisphere (SH) circulation changes, such as poleward shift of westerly jet and Hadley cell widening, have been typically explored with either coupled general circulation models (CGCMs) prescribing stratospheric ozone or chemistry-climate models (CCMs) prescribing surface boundary conditions. Only few studies have utilized ocean-coupled CCMs with a relatively coarse resolution. To better quantify the role of interactive chemistry and coupled ocean in the ozone-hole-induced SH circulation changes, the present study examines a set of CGCM and CCM simulations archived for the Coupled Model Intercomparison Project phase 5 (CMIP5) and CCM initiative (CCMI). Although inter-model spread of Antarctic ozone depletion is substantially large especially in the austral spring, both CGCMs with relatively simple ozone chemistry and CCMs with fully interactive comprehensive chemistry reasonably well reproduce long-term trends of Antarctic ozone and the associated polar-stratospheric temperature changes. Most models reproduce a poleward shift of SH jet and Hadley-cell widening in the austral summer in the late 20th century as identified in reanalysis datasets. These changes are quasi-linearly related with Antarctic ozone changes, confirming the critical role of Antarctic ozone depletion in the austral-summer zonal-mean circulation changes. The CGCMs with simple but still interactive ozone show slightly stronger circulation changes than those with prescribed ozone. However, the long-term circulation changes in CCMs are largely insensitive to the coupled ocean. While a few models show the enhanced circulation changes when ocean is coupled, others show essentially no changes or even weakened circulation changes. This result suggests that the ozone-hole-related stratosphere-troposphere coupling in the late 20th century may be only weakly sensitive to the coupled ocean.

Living Bone Allotransplants Survive by Surgical Angiogenesis Alone: Development of a Novel Method of Composite Tissue Allotransplantation

PubMed Central

Larsen, Mikko; Pelzer, Michael; Friedrich, Patricia F.; Wood, Christina M.; Bishop, Allen T.

2011-01-01

Background: Segmental bone defects pose reconstructive challenges. Composite tissue allotransplantation offers a potential solution but requires long-term immunosuppression with attendant health risks. This study demonstrates a novel method of composite-tissue allotransplantation, permitting long-term drug-free survival, with use of therapeutic angiogenesis of autogenous vessels to maintain circulation. Methods: Ninety-three rats underwent femoral allotransplantation, isotransplantation, or allografting. Group-1 femora were transplanted across a major histocompatibility complex barrier, with microsurgical pedicle anastomoses. The contralateral saphenous artery and vein (termed the AV bundle) of the recipient animal were implanted within the medullary canal to allow development of an autogenous circulation. In Group 2, allotransplantation was also performed, but with AV bundle ligation. Group 3 bones were frozen allografts rather than composite-tissue allotransplantation femora, and Group 4 bones were isotransplants. Paired comparison allowed evaluation of AV bundle effect, bone allogenicity (isogeneic or allogeneic), and initial circulation and viability (allotransplant versus allograft). Two weeks of immunosuppression therapy maintained blood flow initially, during development of a neoangiogenic autogenous blood supply from the AV bundle in patent groups. At eighteen weeks, skin grafts from donor, recipient, and third-party rats were tested for immunocompetence and donor-specific tolerance. At twenty-one weeks, bone circulation was quantified and new bone formation was measured. Results: Final circulatory status depended on both the initial viability of the graft and the successful development of neoangiogenic circulation. Median cortical blood flow was highest in Group 1 (4.6 mL/min/100 g), intermediate in Group 4 isotransplants (0.4 mL/min/100 g), and absent in others. Capillary proliferation and new bone formation were generally highest in allotransplants (15.0%, 6.4 μm3/μm2/yr) and isotransplants with patent AV bundles (16.6%, 50.3 μm3/μm2/yr) and less in allotransplants with ligated AV bundles (4.4%, 0.0 μm3/μm2/yr) or allografts (8.1%, 24.1 μm3/μm2/yr). Donor and third-party-type skin grafts were rejected, indicating immunocompetence without donor-specific tolerance. Conclusions: In the rat model, microvascular allogeneic bone transplantation in combination with short-term immunosuppression and AV bundle implantation creates an autogenous neoangiogenic circulation, permitting long-term allotransplant survival with measurable blood flow. Clinical Relevance: These methods may allow future composite-tissue allotransplantation of bone without the appreciable health risks that are associated with long-term immunosuppression or immune tolerance induction. PMID:21266640

A cost-sharing formula for online circulation and a union catalog through a regional, multitype library cooperative.

PubMed Central

Arcari, R D

1987-01-01

The experience of the Capitol Region Library Council and the University of Connecticut Health Center in developing a cost allocation formula for a circulation and online catalog shared by twenty-nine libraries is reviewed. The resulting formula identifies a basic unit cost as a minimum for each system participant. PMID:3676536

Coastal Ocean Circulation Experiment off Senegal (COCES - II)

DTIC Science & Technology

2013-09-30

II) Pierre-Marie Poulain Istituto Nazionale di Oceanografia e di Geofisica Sperimentale Borgo Grotta Gigante , 42/c 34010 Sgonico (Trieste), Italy...region strongly dominated by coastal upwelling. Specific goals are: 1. to construct unbiased statistics of near surface circulation; 2. to describe...Geophysics,Borgo Grotta Gigante , 42/c,34010 Sgonico (Trieste), Italy, 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S

The Sensitivity of the Midlatitude Moist Isentropic Circulation on Both Sides of the Climate Model Hierarchy

NASA Astrophysics Data System (ADS)

Fajber, R. A.; Kushner, P. J.; Laliberte, F. B.

2017-12-01

In the midlatitude atmosphere, baroclinic eddies are able to raise warm, moist air from the surface into the midtroposphere where it condenses and warms the atmosphere through latent heating. This coupling between dynamics and moist thermodynamics motivates using a conserved moist thermodynamic variable, such as the equivalent potential temperature, to study the midlatitude circulation and associated heat transport since it implicitly accounts for latent heating. When the equivalent potential temperature is used to zonally average the circulation, the moist isentropic circulation takes the form of a single cell in each hemisphere. By utilising the statistical transformed Eulerian mean (STEM) circulation we are able to parametrize the moist isentropic circulation in terms of second order dynamic and moist thermodynamic statistics. The functional dependence of the STEM allows us to analytically calculate functional derivatives that reveal the spatially varying sensitivity of the moist isentropic circulation to perturbations in different statistics. Using the STEM functional derivatives as sensitivity kernels we interpret changes in the moist isentropic circulation from two experiments: surface heating in an idealised moist model, and a climate change scenario in a comprehensive atmospheric general circulation model. In both cases we find that the changes in the moist isentropic circulation are well predicted by the functional sensitivities, and that the total heat transport is more sensitive to changes in dynamical processes driving local changes in poleward heat transport than it is to thermodynamic and/or radiative processes driving changes to the distribution of equivalent potential temperature.

Operational experience with the supercritical helium during the TF coils tests campaign of SST-1

NASA Astrophysics Data System (ADS)

Panchal, Rohitkumar Natvarlal; Patel, Rakesh; Tank, Jignesh; Mahesuria, Gaurang; Sonara, Dashrath; Tanna, Vipul; Patel, Jayant; Srikanth, G. L. N.; Singh, Manoj; Patel, Ketan; Christian, Dikens; Garg, Atul; Bairagi, Nitn; Gupta, Manoj Kumar; Nimavat, Hiren; Shah, Pankil; Sharma, Rajiv; Pradhan, Subrata

2012-06-01

Under the 'SST-1 mission mandate' recently, all the sixteen Steady State Superconducting Tokamak (SST-1) Toroidal Field (TF) magnets have been successfully tested at their nominal currents of 10000 A in cold under supercritical helium (SHe) flow conditions. The TF magnets test campaign have begun in an experimental cryostat since June 2010 with the SST-1 Helium cryogenics facility, which is a 1.3 kW at 4.5 K helium refrigerator-cum-liquefier (HRL) system. The HRL provides ~300 g-s-1supercritical helium (SHe) with cold circulator (CC) as well as ~ 60 g-s-1 without cold circulator to fulfill the forced flow cooling requirements of SST- 1 magnets. In case of single TF coil tests, we can adjust HRL process parameters such that an adequate amount of required supercritical helium is available without the cold circulator. In this paper, the complete process is describing the Process Flow Diagram (PFD) of 1.3 kW at 4.5 K HRL, techniques to generate supercritical helium without using the cold-circulator and the results of the cooldown, steady state characteristics and experience of supercritical helium operations during the TF coils test campaign have been discussed.

Rotor Wake Development During the First Revolution

NASA Technical Reports Server (NTRS)

McAlister, Kenneth W.

2003-01-01

The wake behind a two-bladed model rotor in light climb was measured using particle image velocimetry, with particular emphasis on the development of the trailing vortex during the first revolution of the rotor. The distribution of vorticity was distinguished from the slightly elliptical swirl pattern. Peculiar dynamics within the void region may explain why the peak vorticity appeared to shift away from the center as the vortex aged, suggesting the onset of instability. The swirl and axial velocities (which reached 44 and 12 percent of the rotor-tip speed, respectively) were found to be asymmetric relative to the vortex center. In particular, the axial flow was composed of two concentrated zones moving in opposite directions. The radial distribution of the circulation rapidly increased in magnitude until reaching a point just beyond the core radius, after which the rate of growth decreased significantly. The core-radius circulation increased slightly with wake age, but the large-radius circulation appeared to remain relatively constant. The radial distributions of swirl velocity and vorticity exhibit self-similar behaviors, especially within the core. The diameter of the vortex core was initially about 10 percent of the rotor-blade chord, but more than doubled its size after one revolution of the rotor. According to vortex models that approximate the measured data, the core-radius circulation was about 79 percent of the large-radius circulation, and the large-radius circulation was about 67 percent of the maximum bound circulation on the rotor blade. On average, about 53 percent of the maximum bound circulation resides within the vortex core during the first revolution of the rotor.

Impacts of Local Soil Moisture Anomalies on the Atmospheric Circulation and on Remote Surface Meteorological Fields During Boreal Summer: A Comprehensive Analysis over North America

NASA Technical Reports Server (NTRS)

Koster, Randal D.; Chang, Yehui; Wang, Hailan; Schubert, Siegfried D.

2016-01-01

We perform a series of stationary wave model (SWM) experiments in which the boreal summer atmosphere is forced, over a number of locations in the continental U.S., with an idealized diabatic heating anomaly that mimics the atmospheric heating associated with a dry land surface. For localized heating within a large portion of the continental interior, regardless of the specific location of this heating, the spatial pattern of the forced atmospheric circulation anomaly (in terms of 250-mb eddy streamfunction) is largely the same: a high anomaly forms over west central North America and a low anomaly forms to the east. In supplemental atmospheric general circulation model (AGCM) experiments, we find similar results; imposing soil moisture dryness in the AGCM in different locations within the US interior tends to produce the aforementioned pattern, along with an associated near-surface warming and precipitation deficit in the center of the continent. The SWM-based and AGCM-based patterns generally agree with composites generated using reanalysis and precipitation gauge data. The AGCM experiments also suggest that dry anomalies imposed in the lower Mississippi Valley have remote surface impacts of particularly large spatial extent, and a region along the eastern half of the US-Canada border is particularly sensitive to dry anomalies in a number of remote areas. Overall, the SWM and AGCM experiments support the idea of a positive feedback loop operating over the continent: dry surface conditions in many interior locations lead to changes in atmospheric circulation that act to enhance further the overall dryness of the continental interior.

The role of neutrophils and monocytic cells in controlling the initiation of Clostridium perfringens gas gangrene.

PubMed

O'Brien, David K; Therit, Blair H; Woodman, Michael E; Melville, Stephen B

2007-06-01

Clostridium perfringens is a common cause of the fatal disease gas gangrene (myonecrosis). Established gas gangrene is notable for a profound absence of neutrophils and monocytic cells (phagocytes), and it has been suggested that the bactericidal activities of these cells play an insignificant role in controlling the progression of the infection. However, large inocula of bacteria are needed to establish an infection in experimental animals, suggesting phagocytes may play a role in inhibiting the initiation of gangrene. Examination of tissue sections of mice infected with a lethal (1 x 10(9)) or sublethal (1 x 10(6)) inoculum of C. perfringens revealed that phagocyte infiltration in the first 3 h postinfection was inhibited with a lethal dose but not with a sublethal dose, indicating that exclusion of phagocytes begins very early in the infection cycle. Experiments in which mice were depleted of either circulating monocytes or neutrophils before infection with C. perfringens showed that monocytes play a role in inhibiting the onset of gas gangrene at intermediate inocula but, although neutrophils can slow the onset of the infection, they are not protective. These results suggest that treatments designed to increase monocyte infiltration and activate macrophages may lead to increased resistance to the initiation of gas gangrene.

An Analysis of Results of a High-Resolution World Ocean Circulation Model.

DTIC Science & Technology

1988-03-01

Level Experiments ............... 16 a. Baseline (Laplacian Mixing) Integration ........ 16 b. Isopycnal Mixing Integration ................... 18 3...One-Half Degree, Twenty Level Experiments .......... 18 a. Baseline (Three Year Interior Restoring) Integration...TWENTY LEVEL EXPERIMENTS .................... 21 1. Baseline (Laplacian Mixing) Integration ............. 21 2. Isopycnal Mixing Integration

A personal history of the human exploration initiative with commentary on the pivotal role for life support research

NASA Technical Reports Server (NTRS)

Mendell, Wendell

1990-01-01

The author relates the history of the human exploration initiative from a personal perspective from the 1961 J. F. Kennedy initiative to land a man on the moon up to 1986 when a memo was circulated from NASA Headquarters to its employees which stated as a major goal the expansion of the human presence beyond Earth into the solar system. The pivotal role of life support research is woven into this personalized history.

Motion of Air Bubbles in Water Subjected to Microgravity Accelerations

NASA Technical Reports Server (NTRS)

DeLombard, Richard; Kelly, Eric M.; Hrovat, Kenneth; Nelson, Emily S.; Pettit, Donald R.

2006-01-01

The International Space Station (ISS) serves as a platform for microgravity research for the foreseeable future. A microgravity environment is one in which the effects of gravity are drastically reduced which then allows physical experiments to be conducted without the over powering effects of gravity. During his 6-month stay on the ISS, astronaut Donald R. Pettit performed many informal/impromptu science experiments with available equipment. One such experiment focused on the motion of air bubbles in a rectangular container nearly filled with de-ionized water. Bubbles were introduced by shaking and then the container was secured in place for several hours while motion of the bubbles was recorded using time-lapse photography. This paper shows correlation between bubble motion and quasi-steady acceleration levels during one such experiment operation. The quasi-steady acceleration vectors were measured by the Microgravity Acceleration Measurement System (MAMS). Essentially linear motion was observed in the condition considered here. Dr. Pettit also created other conditions which produced linear and circulating motion, which are the subjects of further study. Initial observations of this bubble motion agree with calculations from many microgravity physical science experiments conducted on shuttle microgravity science missions. Many crystal-growth furnaces involve heavy metals and high temperatures in which undesired acceleration-driven convection during solidification can adversely affect the crystal. Presented in this paper will be results showing correlation between bubble motion and the quasi-steady acceleration vector.

A three-dimensional ocean mesoscale simulation using data from the SEMAPHORE experiment: Mixed layer heat budget

NASA Astrophysics Data System (ADS)

Caniaux, Guy; Planton, Serge

1998-10-01

A primitive equation model is used to simulate the mesoscale circulation associated with a portion of the Azores Front investigated during the intensive observation period (IOP) of the Structure des Echanges Mer-Atmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE) experiment in fall 1993. The model is a mesoscale version of the ocean general circulation model (OGCM) developed at the Laboratoire d'Océanographie Dynamique et de Climatologie (LODYC) in Paris and includes open lateral boundaries, a 1.5-level-order turbulence closure scheme, and fine mesh resolution (0.11° for latitude and 0.09° for longitude). The atmospheric forcing is provided by satellite data for the solar and infrared fluxes and by analyzed (or reanalyzed for the wind) atmospheric data from the European Centre for Medium-Range Weather Forecasts (ECMWF) forecast model. The extended data set collected during the IOP of SEMAPHORE enables a detailed initialization of the model, a coupling with the rest of the basin through time dependent open boundaries, and a model/data comparison for validation. The analysis of model outputs indicates that most features are in good agreement with independent available observations. The surface front evolution is subject to an intense deformation different from that of the deep front system, which evolves only weakly. An estimate of the upper layer heat budget is performed during the 22 days of the integration of the model. Each term of this budget is analyzed according to various atmospheric events that occurred during the experiment, such as the passage of a strong storm. This facilitates extended estimates of mixed layer or relevant surface processes beyond those which are obtainable directly from observations. Surface fluxes represent 54% of the heat loss in the mixed layer and 70% in the top 100-m layer, while vertical transport at the mixed layer bottom accounts for 31% and three-dimensional processes account for 14%.

Wind effect on the Atlantic meridional overturning circulation via sea ice and vertical diffusion

NASA Astrophysics Data System (ADS)

Yang, Haijun; Wang, Kun; Dai, Haijin; Wang, Yuxing; Li, Qing

2016-06-01

Effects of wind and fresh water on the Atlantic meridional overturning circulation (AMOC) are investigated using a fully coupled climate model. The AMOC can change significantly when perturbed by either wind stress or freshwater flux in the North Atlantic. This study focuses on wind stress effect. Our model results show that the wind forcing is crucial in maintaining the AMOC. Reducing wind forcing over the ocean can cause immediately weakening of the vertical salinity diffusion and convection in the mid-high latitudes Atlantic, resulting in an enhancement of vertical salinity stratification that restrains the deep water formation there, triggering a slowdown of the thermohaline circulation. As the thermohaline circulation weakens, the sea ice expands southward and melts, providing the upper ocean with fresh water that weakens the thermohaline circulation further. The wind perturbation experiments suggest a positive feedback between sea-ice and thermohaline circulation strength, which can eventually result in a complete shutdown of the AMOC. This study also suggests that sea-ice variability may be also important to the natural AMOC variability on decadal and longer timescales.

Antarctic glaciation caused ocean circulation changes at the Eocene-Oligocene transition

NASA Astrophysics Data System (ADS)

Goldner, A.; Herold, N.; Huber, M.

2014-07-01

Two main hypotheses compete to explain global cooling and the abrupt growth of the Antarctic ice sheet across the Eocene-Oligocene transition about 34 million years ago: thermal isolation of Antarctica due to southern ocean gateway opening, and declining atmospheric CO2 (refs 5, 6). Increases in ocean thermal stratification and circulation in proxies across the Eocene-Oligocene transition have been interpreted as a unique signature of gateway opening, but at present both mechanisms remain possible. Here, using a coupled ocean-atmosphere model, we show that the rise of Antarctic glaciation, rather than altered palaeogeography, is best able to explain the observed oceanographic changes. We find that growth of the Antarctic ice sheet caused enhanced northward transport of Antarctic intermediate water and invigorated the formation of Antarctic bottom water, fundamentally reorganizing ocean circulation. Conversely, gateway openings had much less impact on ocean thermal stratification and circulation. Our results support available evidence that CO2 drawdown--not gateway opening--caused Antarctic ice sheet growth, and further show that these feedbacks in turn altered ocean circulation. The precise timing and rate of glaciation, and thus its impacts on ocean circulation, reflect the balance between potentially positive feedbacks (increases in sea ice extent and enhanced primary productivity) and negative feedbacks (stronger southward heat transport and localized high-latitude warming). The Antarctic ice sheet had a complex, dynamic role in ocean circulation and heat fluxes during its initiation, and these processes are likely to operate in the future.

A numerical study of circulation in the Gulf of Riga, Baltic Sea. Part I: Whole-basin gyres and mean currents

NASA Astrophysics Data System (ADS)

Lips, Urmas; Zhurbas, Victor; Skudra, Maris; Väli, Germo

2016-01-01

A regional model of the Gulf of Riga (GoR) with horizontal grid spacing of 0.5 nautical miles was applied to study the features and driving forces of the whole-basin circulation in the GoR. The initial conditions and atmospheric forcing were taken from the operational models High Resolution Operational Model for the Baltic (HIROMB) and High Resolution Limited Area Model (HIRLAM), respectively. The wind stress curl is shown to be a major contributor to the whole-basin circulation pattern. An anticyclonic circulation pattern in the summer is determined by a combined effect of the negative wind stress curl, thermal density stratification and bottom topography. Positive values of the wind stress curl and a cyclonic circulation pattern prevail during the cold period of the year when seasonal thermocline is absent. During calm periods, the anticyclonic type of circulation is established due to a combined effect of the river runoff, saltier water inflow into and mixed water outflow from the GoR. Two seasonal baroclinic jet-like currents are identified in the summer: the Northward Longshore Current in the western GoR and Southward Subsurface Longshore Current in the eastern GoR. The alteration of the circulation pattern in the GoR from cyclonic in the cold period of the year to anticyclonic in the summer, and vice versa, was shown to be observed not every year due to inter-annual variability of wind forcing.

Antarctic glaciation caused ocean circulation changes at the Eocene-Oligocene transition.

PubMed

Goldner, A; Herold, N; Huber, M

2014-07-31

Two main hypotheses compete to explain global cooling and the abrupt growth of the Antarctic ice sheet across the Eocene-Oligocene transition about 34 million years ago: thermal isolation of Antarctica due to southern ocean gateway opening, and declining atmospheric CO2 (refs 5, 6). Increases in ocean thermal stratification and circulation in proxies across the Eocene-Oligocene transition have been interpreted as a unique signature of gateway opening, but at present both mechanisms remain possible. Here, using a coupled ocean-atmosphere model, we show that the rise of Antarctic glaciation, rather than altered palaeogeography, is best able to explain the observed oceanographic changes. We find that growth of the Antarctic ice sheet caused enhanced northward transport of Antarctic intermediate water and invigorated the formation of Antarctic bottom water, fundamentally reorganizing ocean circulation. Conversely, gateway openings had much less impact on ocean thermal stratification and circulation. Our results support available evidence that CO2 drawdown--not gateway opening--caused Antarctic ice sheet growth, and further show that these feedbacks in turn altered ocean circulation. The precise timing and rate of glaciation, and thus its impacts on ocean circulation, reflect the balance between potentially positive feedbacks (increases in sea ice extent and enhanced primary productivity) and negative feedbacks (stronger southward heat transport and localized high-latitude warming). The Antarctic ice sheet had a complex, dynamic role in ocean circulation and heat fluxes during its initiation, and these processes are likely to operate in the future.

Aeroacoustic interaction of a distributed vortex with a lifting Joukowski airfoil

NASA Technical Reports Server (NTRS)

Hardin, J. C.; Lamkin, S. L.

1984-01-01

A first principles computational aeroacoustics calculation of the flow and noise fields produced by the interaction of a distributed vortex with a lifting Joukowski airfoil is accomplished at the Reynolds number of 200. The case considered is that where the circulations of the vortex and the airfoil are of opposite sign, corresponding to blade vortex interaction on the retreating side of a single helicopter rotor. The results show that the flow is unsteady, even in the absence of the incoming vortex, resulting in trailing edge noise generation. After the vortex is input, it initially experiences a quite rapid apparent diffusion rate produced by stretching in the airfoil velocity gradients. Consideration of the effects of finite vortex size and viscosity causes the noise radiation during the encounter to be much less impulsive than predicted by previous analyses.

Atmospheric Test Models and Numerical Experiments for the Simulation of the Global Distributions of Weather Data Transponders III. Horizontal Distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molenkamp, C.R.; Grossman, A.

1999-12-20

A network of small balloon-borne transponders which gather very high resolution wind and temperature data for use by modern numerical weather predication models has been proposed to improve the reliability of long-range weather forecasts. The global distribution of an array of such transponders is simulated using LLNL's atmospheric parcel transport model (GRANTOUR) with winds supplied by two different general circulation models. An initial study used winds from CCM3 with a horizontal resolution of about 3 degrees in latitude and longitude, and a second study used winds from NOGAPS with a 0.75 degree horizontal resolution. Results from both simulations show thatmore » reasonable global coverage can be attained by releasing balloons from an appropriate set of launch sites.« less

An intense, quasi-steady thunderstorm over mountainous terrain. I - Evolution of the storm-initiating mesoscale circulation

NASA Technical Reports Server (NTRS)

Cotton, W. R.; George, R. L.; Knupp, K. R.

1982-01-01

The evolution of mesoscale systems that eventually lead to the formation of large quasi-steady storm systems is investigated. The morphological and turbulent structure of the quasi-steady storm is described. Data obtained during the South Park Area Cumulus Experiment from surface meteorological stations, rawinsondes and tethered balloons, conventional and Doppler radars, powered aircraft, and satellites, indicate that on July 19, 1977, a north-south oriented line of intense convective cells formed and remained within South Park. Elevated surface heating created a region of low-level convergence, importing Pacific moisture from west of the Rockies. The mesoscale thunderstorm line formed over this convergence zone, and a single large convective cell was observed to grow on the southern end of the mesoscale line, exhibiting supercell characteristics and substantial modifications of the environmental flow.

Structural coloration signals condition, parental investment, and circulating hormone levels in Eastern bluebirds (Sialia sialis).

PubMed

Grindstaff, Jennifer L; Lovern, Matthew B; Burtka, Jennifer L; Hallmark-Sharber, Alesia

2012-08-01

Many of the brilliant plumage coloration displays of birds function as signals to conspecifics. One species in which the function of plumage ornaments has been assessed is the Eastern bluebird (Sialia sialis). Studies of a population breeding in Alabama (USA) have established that plumage ornaments signal quality, parental investment, and competitive ability in both sexes. Here we tested the additional hypotheses that (1) Eastern bluebird plumage ornamentation signals nest defense behavior in heterospecific competitive interactions and (2) individual variation in plumage ornamentation reflects underlying differences in circulating hormone levels. We also tested the potential for plumage ornaments to signal individual quality and parental investment in a population breeding in Oklahoma (USA). We found that Eastern bluebirds with more ornamented plumage are in better condition, initiate breeding earlier in the season, produce larger clutches, have higher circulating levels of the stress hormone corticosterone, and more ornamented males have lower circulating androgen levels. Plumage coloration was not related to nest defense behavior. Thus, plumage ornamentation may be used by both sexes to assess the physiological condition and parental investment of prospective mates. Experimental manipulations of circulating hormone levels during molt are needed to define the role of hormones in plumage ornamentation.

Initial conditions and ENSO prediction using a coupled ocean-atmosphere model

NASA Astrophysics Data System (ADS)

Larow, T. E.; Krishnamurti, T. N.

1998-01-01

A coupled ocean-atmosphere initialization scheme using Newtonian relaxation has been developed for the Florida State University coupled ocean-atmosphere global general circulation model. The initialization scheme is used to initialize the coupled model for seasonal forecasting the boreal summers of 1987 and 1988. The atmosphere model is a modified version of the Florida State University global spectral model, resolution T-42. The ocean general circulation model consists of a slightly modified version of the Hamburg's climate group model described in Latif (1987) and Latif et al. (1993). The coupling is synchronous with information exchanged every two model hours. Using ECMWF atmospheric daily analysis and observed monthly mean SSTs, two, 1-year, time-dependent, Newtonian relaxation were performed using the coupled model prior to conducting the seasonal forecasts. The coupled initializations were conducted from 1 June 1986 to 1 June 1987 and from 1 June 1987 to 1 June 1988. Newtonian relaxation was applied to the prognostic atmospheric vorticity, divergence, temperature and dew point depression equations. In the ocean model the relaxation was applied to the surface temperature. Two, 10-member ensemble integrations were conducted to examine the impact of the coupled initialization on the seasonal forecasts. The initial conditions used for the ensembles are the ocean's final state after the initialization and the atmospheric initial conditions are ECMWF analysis. Examination of the SST root mean square error and anomaly correlations between observed and forecasted SSTs in the Niño-3 and Niño-4 regions for the 2 seasonal forecasts, show closer agreement between the initialized forecast than two, 10-member non-initialized ensemble forecasts. The main conclusion here is that a single forecast with the coupled initialization outperforms, in SST anomaly prediction, against each of the control forecasts (members of the ensemble) which do not include such an initialization, indicating possible importance for the inclusion of the atmosphere during the coupled initialization.

Label-free detection of circulating melanoma cells by in vivo photoacoustic flow cytometry

NASA Astrophysics Data System (ADS)

Wang, Xiaoling; Yang, Ping; Liu, Rongrong; Niu, Zhenyu; Suo, Yuanzhen; He, Hao; Gao, Wenyuan; Tang, Shuo; Wei, Xunbin

2016-03-01

Melanoma is a malignant tumor of melanocytes. Melanoma cells have high light absorption due to melanin highly contained in melanoma cells. This property is employed for the detection of circulating melanoma cell by in vivo photoacoustic flow cytometry (PAFC), which is based on photoacoustic effect. Compared to in vivo flow cytometry based on fluorescence, PAFC can employ high melanin content of melanoma cells as endogenous biomarkers to detect circulating melanoma cells in vivo. We have developed in vitro experiments to prove the ability of PAFC system of detecting photoacoustic signals from melanoma cells. For in vivo experiments, we have constructed a model of melanoma tumor bearing mice by inoculating highly metastatic murine melanoma cancer cells, B16F10 with subcutaneous injection. PA signals are detected in the blood vessels of mouse ears in vivo. The raw signal detected from target cells often contains some noise caused by electronic devices, such as background noise and thermal noise. We choose the Wavelet denoising method to effectively distinguish the target signal from background noise. Processing in time domain and frequency domain would be combined to analyze the signal after denoising. This algorithm contains time domain filter and frequency transformation. The frequency spectrum image of the signal contains distinctive features that can be used to analyze the property of target cells or particles. The processing methods have a great potential for analyzing signals accurately and rapidly. By counting circulating melanoma cells termly, we obtain the number variation of circulating melanoma cells as melanoma metastasized. Those results show that PAFC is a noninvasive and label-free method to detect melanoma metastases in blood or lymph circulation.

Spectral Energetics Diagnoses and FGGE Special Observing Periods and Energetics Analyses of Forecast Experiments with GLAS GCM

NASA Technical Reports Server (NTRS)

Kung, E. C.

1984-01-01

Energetics characteristics of Goddard Laboratory for Atmospheric Sciences (GLAS) General Circulation Models (GCM) as they are reflected on the First GARD GLobal Experiment (FGGE) analysis data set are discussed. Energetics descriptions of GLAS GCM forecast experiments are discussed as well as Eneretics response of GLAS GCM climatic simulation experiments.

World Ocean Circulation Experiment (WOCE) Young Investigator Workshops

NASA Technical Reports Server (NTRS)

Austin, Meg

2004-01-01

The World Ocean Circulation Experiment (WOCE) Young Investigator Workshops goals and objectives are: a) to familiarize Young Investigators with WOCE models, datasets and estimation procedures; b) to offer intensive hands-on exposure to these models ard methods; c) to build collaborations among junior scientists and more senior WOCE investigators; and finally, d) to generate ideas and projects leading to fundable WOCE synthesis projects. To achieve these goals and objectives, the Workshop will offer a mixture of tutorial lectures on numerical models and estimation procedures, advanced seminars on current WOCE synthesis activities and related projects, and the opportunity to conduct small projects which put into practice the techniques advanced in the lectures.

Tropical Atlantic-Korea teleconnection pattern during boreal summer season

NASA Astrophysics Data System (ADS)

Ham, Yoo-Geun; Chikamoto, Yoshimitsu; Kug, Jong-Seong; Kimoto, Masahide; Mochizuki, Takashi

2017-10-01

The remote impact of tropical Atlantic sea surface temperature (SST) variability on Korean summer precipitation is examined based on observational data analysis along with the idealized and hindcast model experiments. Observations show a significant correlation (i.e. 0.64) between Korean precipitation anomalies (averaged over 120-130°E, 35-40°N) and the tropical Atlantic SST index (averaged over 60°W-20°E, 30°S-30°N) during the June-July-August (JJA) season for the 1979-2010 period. Our observational analysis and partial-data assimilation experiments using the coupled general circulation model demonstrate that tropical Atlantic SST warming induces the equatorial low-level easterly over the western Pacific through a reorganization of the global Walker Circulation, causing a decreased precipitation over the off-equatorial western Pacific. As a Gill-type response to this diabatic forcing, an anomalous low-level anticyclonic circulation appears over the Philippine Sea, which transports wet air from the tropics to East Asia through low-level southerly, resulting an enhanced precipitation in the Korean peninsula. Multi-model hindcast experiments also show that predictive skills of Korean summer precipitation are improved by utilizing predictions of tropical Atlantic SST anomalies as a predictor for Korean precipitation anomalies.

A novel small animal extracorporeal circulation model for studying pathophysiology of cardiopulmonary bypass.

PubMed

Fujii, Yutaka; Shirai, Mikiyasu; Inamori, Shuji; Takewa, Yoshiaki; Tatsumi, Eisuke

2015-03-01

Extracorporeal circulation (ECC) is indispensable for cardiac surgery. Despite the fact that ECCcauses damage to blood components and is non-physiologic, its pathophysiology has not been fully elucidated. This is because difficulty in clinical research and animal experiments keeps the knowledge insufficient. Therefore, it is desirable to have a miniature ECC model for small animals, which enables repetitive experiments, to study the mechanism of pathophysiological changes during ECC. We developed a miniature ECC system and applied it to the rat. We measured changes in hemodynamics, blood gases and hemoglobin (Hb) concentration, serum cytokines (TNF-α, IL-6, IL-10), biochemical markers (LDH, AST, ALT), and the wet-to-dry weight (W/D) ratio of the lung for assessing whether the rat ECC model is comparable to the human ECC. The ECC system consisted of a membranous oxygenator (polypropylene, 0.03 m(2)), tubing line (polyvinyl chloride), and roller pump. Priming volume of this system is only 8 ml. Rats (400-450 g) were divided into the SHAM group (n = 7) and the ECC group (n = 7). Blood samples were collected before, 60 and 120 min after initiation of ECC. During ECC, blood pressure and Hb were maintained around 80 mmHg and 10 g/dL, respectively. The levels of the inflammatory and biochemical markers and the W/D ratio were significantly elevated in the ECC group, indicating some organ damages and systemic inflammatory responses during ECC. We successfully established the ECC for the rat. This miniature ECC model could be a useful approach for studying the mechanism of pathophysiology during ECC and basic assessment of the ECC devices.

A Last Glacial Maximum world-ocean simulation at eddy-permitting resolution - Part 1: Experimental design and basic evaluation

NASA Astrophysics Data System (ADS)

Ballarotta, M.; Brodeau, L.; Brandefelt, J.; Lundberg, P.; Döös, K.

2013-01-01

Most state-of-the-art climate models include a coarsely resolved oceanic component, which has difficulties in capturing detailed dynamics, and therefore eddy-permitting/eddy-resolving simulations have been developed to reproduce the observed World Ocean. In this study, an eddy-permitting numerical experiment is conducted to simulate the global ocean state for a period of the Last Glacial Maximum (LGM, ~ 26 500 to 19 000 yr ago) and to investigate the improvements due to taking into account these higher spatial scales. The ocean general circulation model is forced by a 49-yr sample of LGM atmospheric fields constructed from a quasi-equilibrated climate-model simulation. The initial state and the bottom boundary condition conform to the Paleoclimate Modelling Intercomparison Project (PMIP) recommendations. Before evaluating the model efficiency in representing the paleo-proxy reconstruction of the surface state, the LGM experiment is in this first part of the investigation, compared with a present-day eddy-permitting hindcast simulation as well as with the available PMIP results. It is shown that the LGM eddy-permitting simulation is consistent with the quasi-equilibrated climate-model simulation, but large discrepancies are found with the PMIP model analyses, probably due to the different equilibration states. The strongest meridional gradients of the sea-surface temperature are located near 40° N and S, this due to particularly large North-Atlantic and Southern-Ocean sea-ice covers. These also modify the locations of the convection sites (where deep-water forms) and most of the LGM Conveyor Belt circulation consequently takes place in a thinner layer than today. Despite some discrepancies with other LGM simulations, a glacial state is captured and the eddy-permitting simulation undertaken here yielded a useful set of data for comparisons with paleo-proxy reconstructions.

Circulating nucleic acids and evolution.

PubMed

Anker, Philippe; Stroun, Maurice

2012-06-01

J.B. Lamarck in 1809 was the first to present a theory of evolution. He proposed it was due to the adaptation of species to environmental changes, this adaptation being acquired by the offspring. In 1868, Darwin suggested that cells excrete gemmules, which circulate through the body and reach the gonads where they are transmitted to the next generation. His main argument came from graft hybrids. In the fifties and sixties, Russian geneticists, rejecting neo-Darwinism, said that acquired characteristics were the basis of evolution. The main experiments on which they based their theory were the transmission of hereditary characteristics by a special technique of grafting between two varieties of plants. We repeated this kind of experiment and also succeeded in obtaining hereditary modifications of the pupil plants that acquired some characteristics of the mentor variety. Rather than adopting the views of the Russian scientists, we suggested that DNA was circulating between the mentor and pupil plants. Hirata's group have shown recently, by using molecular techniques such as cloning, RFLP PCR and sequencing some genes of their graft hybrids of pepper plants, that transfer of informative molecules from the mentor to the pupil plant does exist. Nucleic acids are actively released by cells; they circulate in the body. They can transform oncogenically or trigger antibody response but the only genetic transformation showing that DNA can go from the soma to the germen comes from graft hybrids. This suggests that circulating nucleic acids, in this case DNA, like Darwin's gemmules, play a role in the mechanism of evolution.

A Forecast Skill Comparison between CliPAS One-Tier and Two-Tier Hindcast Experiments

NASA Astrophysics Data System (ADS)

Lee, J.; Wang, B.; Kang, I.

2006-05-01

A 24-year (1981-2004) MME hindcast experimental dataset is produced under the "Climate Prediction and Its Application to Society" (CliPAS) project sponsored by Korean Meteorological Administration (KMA). This dataset consists of 5 one-tier model systems from National Aeronautics and Space Administration (NASA), National Center for Environmental Prediction (NCEP), Frontier Research Center for Global Change (FRCGC), Seoul National University (SNU), and University of Hawaii (UH) and 5 two-tier model systems from Florida State University (FSU), Geophysical Fluid Dynamic Lab (GFDL), SNU, and UH. Multi-model Ensemble (MME) Forecast skills of seasonal precipitation and atmospheric circulation are compared between CliPAS one-tier and two-tier hindcast experiments for seasonal mean precipitation and atmospheric circulation. For winter prediction, two-tier MME has a comparable skill to one-tier MME. However, it is demonstrated that in the Asian-Australian monsoon (A-AM) heavy precipitation regions, one-tier systems are superior to two-tier systems in summer season. The reason is that inclusion of the local warm pool- monsoon interaction in the one-tier system improves the ENSO teleconnection with monsoon regions. Both one-tier and two-tier MME fail to predict Indian monsoon circulation, while they have a significantly good skill for the broad scale monsoon circulation defined by Webster and Yang index. One-tier system has a much better skill to predict the monsoon circulation over the western North pacific where air-sea interaction plays an important role than two-tier system.

Design of Complex Systems to Achieve Passive Safety: Natural Circulation Cooling of Liquid Salt Pebble Bed Reactors

NASA Astrophysics Data System (ADS)

Scarlat, Raluca Olga

This dissertation treats system design, modeling of transient system response, and characterization of individual phenomena and demonstrates a framework for integration of these three activities early in the design process of a complex engineered system. A system analysis framework for prioritization of experiments, modeling, and development of detailed design is proposed. Two fundamental topics in thermal-hydraulics are discussed, which illustrate the integration of modeling and experimentation with nuclear reactor design and safety analysis: thermal-hydraulic modeling of heat generating pebble bed cores, and scaled experiments for natural circulation heat removal with Boussinesq liquids. The case studies used in this dissertation are derived from the design and safety analysis of a pebble bed fluoride salt cooled high temperature nuclear reactor (PB-FHR), currently under development in the United States at the university and national laboratories level. In the context of the phenomena identification and ranking table (PIRT) methodology, new tools and approaches are proposed and demonstrated here, which are specifically relevant to technology in the early stages of development, and to analysis of passive safety features. A system decomposition approach is proposed. Definition of system functional requirements complements identification and compilation of the current knowledge base for the behavior of the system. Two new graphical tools are developed for ranking of phenomena importance: a phenomena ranking map, and a phenomena identification and ranking matrix (PIRM). The functional requirements established through this methodology were used for the design and optimization of the reactor core, and for the transient analysis and design of the passive natural circulation driven decay heat removal system for the PB-FHR. A numerical modeling approach for heat-generating porous media, with multi-dimensional fluid flow is presented. The application of this modeling approach to the PB-FHR annular pebble bed core cooled by fluoride salt mixtures generated a model that is called Pod. Pod. was used to show the resilience of the PB-FHR core to generation of hot spots or cold spots, due to the effect of buoyancy on the flow and temperature distribution in the packed bed. Pod. was used to investigate the PB-FHR response to ATWS transients. Based on the functional requirements for the core, Pod. was used to generate an optimized design of the flow distribution in the core. An analysis of natural circulation loops cooled by single-phase Boussinesq fluids is presented here, in the context of reactor design that relies on natural circulation decay heat removal, and design of scaled experiments. The scaling arguments are established for a transient natural circulation loop, for loops that have long fluid residence time, and negligible contribution of fluid inertia to the momentum equation. The design of integral effects tests for the loss of forced circulation (LOFC) for PB-FHR is discussed. The special case of natural circulation decay heat removal from a pebble bed reactor was analyzed. A way to define the Reynolds number in a multi-dimensional pebble bed was identified. The scaling methodology for replicating pebble bed friction losses using an electrically resistance heated annular pipe and a needle valve was developed. The thermophysical properties of liquid fluoride salts lead to design of systems with low flow velocities, and hence long fluid residence times. A comparison among liquid coolants for the performance of steady state natural circulation heat removal from a pebble bed was performed. Transient natural circulation experimental data with simulant fluids for fluoride salts is given here. The low flow velocity and the relatively high viscosity of the fluoride salts lead to low Reynolds number flows, and a low Reynolds number in conjunction with a sufficiently high coefficient of thermal expansion makes the system susceptible to local buoyancy effects Experiments indicate that slow exchange of stagnant fluid in static legs can play a significant role in the transient response of natural circulation loops. The effect of non-linear temperature profiles on the hot or cold legs or other segments of the flow loop, which may develop during transient scenarios, should be considered when modeling the performance of natural circulation loops. The data provided here can be used for validation of the application of thermal-hydraulic systems codes to the modeling of heat removal by natural circulation with liquid fluoride salts and its simulant fluids.

Assimilation of Sea Color Data Into A Three Dimensional Biogeochemical Model: Sensitivity Experiments

NASA Astrophysics Data System (ADS)

Echevin, V.; Levy, M.; Memery, L.

The assimilation of two dimensional sea color data fields into a 3 dimensional coupled dynamical-biogeochemical model is performed using a 4DVAR algorithm. The biogeochemical model includes description of nitrates, ammonium, phytoplancton, zooplancton, detritus and dissolved organic matter. A subset of the biogeochemical model poorly known parameters (for example,phytoplancton growth, mortality,grazing) are optimized by minimizing a cost function measuring misfit between the observations and the model trajectory. Twin experiments are performed with an eddy resolving model of 5 km resolution in an academic configuration. Starting from oligotrophic conditions, an initially unstable baroclinic anticyclone splits into several eddies. Strong vertical velocities advect nitrates into the euphotic zone and generate a phytoplancton bloom. Biogeochemical parameters are perturbed to generate surface pseudo-observations of chlorophyll,which are assimilated in the model in order to retrieve the correct parameter perturbations. The impact of the type of measurement (quasi-instantaneous, daily mean, weekly mean) onto the retrieved set of parameters is analysed. Impacts of additional subsurface measurements and of errors in the circulation are also presented.

Using Computational Fluid Dynamics and Experiments to Design Sweeping Jets for High Reynolds Number Cruise Configurations

NASA Technical Reports Server (NTRS)

Jones, Gregory S.; Milholen, William E., II; Fell, Jared S.; Webb, Sandy R.; Cagle, C. Mark

2016-01-01

The application of a sweeping jet actuator to a circulation control system was initiated by a risk reduction series of experiments to optimize the authority of a single sweeping jet actuator. The sweeping jet design was integrated into the existing Fundamental Aerodynamic Subsonic Transonic- Modular Active Control (FAST-MAC) model by replacing the steady blowing system with an array of thirty-nine sweeping jet cartridges. A constant slot height to wing chord ratio was similar to the steady blowing configuration resulting in each actuator having a unique in size for the sweeping jet configuration. While this paper will describe the scaling and optimization of the actuators for future high Reynolds number applications, the major focus of this effort was to target the transonic flight regime by increasing the amplitude authority of the actuator. This was accomplished by modifying the diffuser of the sweeping jet actuator, and this paper highlights twelve different diffuser designs. The experimental portion of this work was completed in the NASA Langley National Transonic Facility.

The Arctic Predictability and Prediction on Seasonal-to-Interannual TimEscales (APPOSITE) data set

NASA Astrophysics Data System (ADS)

Day, J. J.; Tietsche, S.; Collins, M.; Goessling, H. F.; Guemas, V.; Guillory, A.; Hurlin, W. J.; Ishii, M.; Keeley, S. P. E.; Matei, D.; Msadek, R.; Sigmond, M.; Tatebe, H.; Hawkins, E.

2015-10-01

Recent decades have seen significant developments in seasonal-to-interannual timescale climate prediction capabilities. However, until recently the potential of such systems to predict Arctic climate had not been assessed. This paper describes a multi-model predictability experiment which was run as part of the Arctic Predictability and Prediction On Seasonal to Inter-annual Timescales (APPOSITE) project. The main goal of APPOSITE was to quantify the timescales on which Arctic climate is predictable. In order to achieve this, a coordinated set of idealised initial-value predictability experiments, with seven general circulation models, was conducted. This was the first model intercomparison project designed to quantify the predictability of Arctic climate on seasonal to inter-annual timescales. Here we present a description of the archived data set (which is available at the British Atmospheric Data Centre) and an update of the project's results. Although designed to address Arctic predictability, this data set could also be used to assess the predictability of other regions and modes of climate variability on these timescales, such as the El Niño Southern Oscillation.

Stem-like plasticity and heterogeneity of circulating tumor cells: current status and prospect challenges in liver cancer

PubMed Central

Correnti, Margherita; Raggi, Chiara

2017-01-01

Poor prognosis and high recurrence remain leading causes of primary liver cancerassociated mortality. The spread of circulating tumor cells (CTCs) in the blood plays a major role in the initiation of metastasis and tumor recurrence after surgery. Nevertheless, only a subset of CTCs can survive, migrate to distant sites and establish secondary tumors. Consistent with cancer stem cell (CSC) hypothesis, stem-like CTCs might represent a potential source for cancer relapse and distant metastasis. Thus, identification of stem-like metastasis-initiating CTC-subset may provide useful clinically prognostic information. This review will emphasize the most relevant findings of CTCs in the context of stem-like biology associated to liver carcinogenesis. In this view, the emerging field of stem-like CTCs may deliver substantial contribution in liver cancer field in order to move to personalized approaches for diagnosis, prognosis and therapy. PMID:27738343

Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 1

NASA Technical Reports Server (NTRS)

Jones, Gregory S. (Editor); Joslin, Ronald D. (Editor)

2005-01-01

As technological advances influence the efficiency and effectiveness of aerodynamic and hydrodynamic applications, designs and operations, this workshop was intended to address the technologies, systems, challenges and successes specific to Coanda driven circulation control in aerodynamics and hydrodynamics. A major goal of this workshop was to determine the 2004 state-of-the-art in circulation control and understand the roadblocks to its application. The workshop addressed applications, CFD, and experiments related to circulation control, emphasizing fundamental physics, systems analysis, and applied research. The workshop consisted of 34 single session oral presentations and written papers that focused on Naval hydrodynamic vehicles (e.g. submarines), Fixed Wing Aviation, V/STOL platforms, propulsion systems (including wind turbine systems), ground vehicles (automotive and trucks) and miscellaneous applications (e.g., poultry exhaust systems and vacuum systems). Several advanced CFD codes were benchmarked using a two-dimensional NCCR circulation control airfoil. The CFD efforts highlighted inconsistencies in turbulence modeling, separation and performance predictions.

High-Reynolds Number Circulation Control Testing in the National Transonic Facility

NASA Technical Reports Server (NTRS)

Milholen, William E., II; Jones, Gregory S.; Chan, David T.; Goodliff, Scott L.

2012-01-01

A new capability to test active flow control concepts and propulsion simulations at high Reynolds numbers in the National Transonic Facility at the NASA Langley Research Center is being developed. The first active flow control experiment was completed using the new FAST-MAC semi-span model to study Reynolds number scaling effects for several circulation control concepts. Testing was conducted over a wide range of Mach numbers, up to chord Reynolds numbers of 30 million. The model was equipped with four onboard flow control valves allowing independent control of the circulation control plenums, which were directed over a 15% chord simple-hinged flap. Preliminary analysis of the uncorrected lift data showed that the circulation control increased the low-speed maximum lift coefficient by 33%. At transonic speeds, the circulation control was capable of positively altering the shockwave pattern on the upper wing surface and reducing flow separation. Furthermore, application of the technique to only the outboard portion of the wing demonstrated the feasibility of a pneumatic based roll control capability.

Effects of block copolymer properties on nanocarrier protection from in vivo clearance

PubMed Central

D’Addio, Suzanne M.; Saad, Walid; Ansell, Steven M.; Squiers, John J.; Adamson, Douglas; Herrera-Alonso, Margarita; Wohl, Adam R.; Hoye, Thomas R.; Macosko, Christopher W.; Mayer, Lawrence D.; Vauthier, Christine; Prud’homme, Robert K.

2012-01-01

Drug nanocarrier clearance by the immune system must be minimized to achieve targeted delivery to pathological tissues. There is considerable interest in finding in vitro tests that can predict in vivo clearance outcomes. In this work, we produce nanocarriers with dense PEG layers resulting from block copolymer-directed assembly during rapid precipitation. Nanocarriers are formed using block copolymers with hydrophobic blocks of polystyrene (PS), poly-ε-caprolactone (PCL), poly-D,L-lactide (PLA), or poly-lactide-co-glycolide (PLGA), and hydrophilic blocks of polyethylene glycol (PEG) with molecular weights from 1.5 kg/mol to 9 kg/mol. Nanocarriers with paclitaxel prodrugs are evaluated in vivo in Foxn1nu mice to determine relative rates of clearance. The amount of nanocarrier in circulation after 4 h varies from 10% to 85% of initial dose, depending on the block copolymer. In vitro complement activation assays are conducted in an effort to correlate the protection of the nanocarrier surface from complement binding and activation and in vivo circulation. Guidelines for optimizing block copolymer structure to maximize circulation of nanocarriers formed by rapid precipitation and directed assembly are proposed, relating to the relative size of the hydrophilic and hydrophobic block, the hydrophobicity of the anchoring block, the absolute size of the PEG block, and polymer crystallinity. The in vitro results distinguish between the poorly circulating PEG5k-PCL9k and the better circulating nanocarriers, but could not rank the better circulating nanocarriers in order of circulation time. Analysis of PEG surface packing on monodisperse 200 nm latex spheres indicates that the sizes of the hydrophobic PCL, PS, and PLA blocks are correlated with the PEG blob size, and possibly the clearance from circulation. Suggestions for next step in vitro measurements are made. PMID:22732478

Oxidative Burst of Circulating Neutrophils Following Traumatic Brain Injury in Human

PubMed Central

Liao, Yiliu; Liu, Peng; Guo, Fangyuan; Zhang, Zhi-Yuan; Zhang, Zhiren

2013-01-01

Besides secondary injury at the lesional site, Traumatic brain injury (TBI) can cause a systemic inflammatory response, which may cause damage to initially unaffected organs and potentially further exacerbate the original injury. Here we investigated plasma levels of important inflammatory mediators, oxidative activity of circulating leukocytes, particularly focusing on neutrophils, from TBI subjects and control subjects with general trauma from 6 hours to 2 weeks following injury, comparing with values from uninjured subjects. We observed increased plasma level of inflammatory cytokines/molecules TNF-α, IL-6 and CRP, dramatically increased circulating leukocyte counts and elevated expression of TNF-α and iNOS in circulating leukocytes from TBI patients, which suggests a systemic inflammatory response following TBI. Our data further showed increased free radical production in leukocyte homogenates and elevated expression of key oxidative enzymes iNOS, COX-2 and NADPH oxidase (gp91phox) in circulating leukocytes, indicating an intense induction of oxidative burst following TBI, which is significantly greater than that in control subjects with general trauma. Furthermore, flow cytometry assay proved neutrophils as the largest population in circulation after TBI and showed significantly up-regulated oxidative activity and suppressed phagocytosis rate for circulating neutrophils following brain trauma. It suggests that the highly activated neutrophils might play an important role in the secondary damage, even outside the injured brain. Taken together, the potent systemic inflammatory response induced by TBI, especially the intensively increase oxidative activity of circulating leukocytes, mainly neutrophils, may lead to a systemic damage, dysfunction/damage of bystander tissues/organs and even further exacerbate secondary local damage. Controlling these pathophysiological processes may be a promising therapeutic strategy and will protect unaffected organs and the injured brain from the secondary damage. PMID:23894384

Climate dynamics along the arid northern coast of Chile: The 1997-1998 Dinámica del Clima de la Región de Antofagasta (DICLIMA) experiment

NASA Astrophysics Data System (ADS)

Rutllant, José A.; Fuenzalida, Humberto; Aceituno, Patricio

2003-09-01

The DICLIMA field experiment was designed to test and quantify the hypothesis of an afternoon enhancement of the coastal subsidence in the extremely arid northern Chile because of solar heating over the west slope of the Andes. Ten-day campaigns near Antofagasta (23°S) were carried out in January 1997, July 1997, and January 1998. Significant diurnal cycles in temperature, mixing ratio, and wind from about 1000 to 4000 m above sea level were observed. This layer was decoupled from the marine boundary layer circulation below by the subsidence inversion when its base was under the average height of the coastal mountain range. The solar heating cycle over the Andes and associated circulation resulted in a mean afternoon zonal divergence above the subsidence inversion base of about 30 × 10-6 s-1, exceeding by a factor of 5 typical subtropical west coast divergences. The corresponding early morning convergence was particularly intense during the austral winter experiment. In spite of the very strong El Niño conditions that prevailed during the July 1997 and January 1998 experiments, the overwhelming control that radiation exerts on the daily cycles of the atmospheric circulation over the west slope of the Andes seems to guarantee the general validity of the results.

Idealized Numerical Modeling Experiments of the Diurnal Cycle of Tropical Cyclones

NASA Astrophysics Data System (ADS)

Navarro, Erika L.

Numerical experiments are performed to evaluate the role of the daily cycle of radiation on axisymmetric hurricane structure. Although a diurnal response in the high cloudiness of tropical cyclones (TCs) has been well documented in the past, the impact to storm structure and intensity remains unknown. Previous modeling work attributes differences in results to experimental setup (e.g., initial and boundary conditions) as well as to radiative parameterization schemes. Here, a numerically-simulated TC in a statistical steady-state is examined to quantify the TC response to the daily cycle of radiation, and a modified, Sawyer-Eliassen approach is applied to evaluate the dynamical mechanism. Fourier analysis in time reveals a spatially coherent pattern in the temperature, wind, and latent heating tendency fields that is statistically significant at the 95% level. This signal accounts for up to 62% of the variance in the temperature field of the upper troposphere, and is mainly concentrated in the TC outflow layer. Composite analysis reveals a cycle in the storm intensity in the low-levels, which lags a periodic response in the latent heating tendency by 6 h. Average magnitudes of the azimuthal wind anomalies near the radius of maximum wind (RMW) are 1 m/s and account for 21% of the overall variance. A hypothesis is drawn from these results that the TC diurnal cycle is comprised of two distinct, periodic circulations: (1) a radiatively-driven circulation in the TC outflow layer due to absorption of solar radiation, and (2) a convectively-driven circulation in the lower and middle troposphere due to anomalous latent heating from convection. These responses are coupled and are periodic with respect to the diurnal cycle. Using a modified, Sawyer-Eliassen approach for time-varying heating, these hypotheses are evaluated to determine the impact of periodic diurnal heating on a balanced vortex. Periodic heating near the top of the vortex produces a local overturning circulation in the region of heating that manifests as inertia-buoyancy waves in the storm environment. Periodic heating in the lower troposphere drives an overturning circulation that resembles the Sawyer-Eliassen solution. This low-level heating induces a positive perturbation azimuthal wind response of 4 m/s near the RMW, which lags the maximum in streamfunction by 6 h. Comparison of these solutions to the numerically-simulated TC reveals a close correspondence of results, suggesting that the axisymmetric TC diurnal cycle is a balanced response driven by periodic heating. The sensitivity of these results to the length of the diurnal period and the vortex intensity are evaluated using the modified, Sawyer-Eliassen approach. Although the true diurnal period is fixed in nature, these experiments allow for the relationship between the magnitude and structure of the TC diurnal signal to the length of the diurnal period to be explored. Results demonstrate that the TC diurnal cycle exhibits large variance, even for the same heating distributions. High-frequency forcing projects mainly onto inertia-buoyancy waves, while low-frequency produces a balanced response resembling the Sawyer-Eliassen solution. Comparison to two, numerically simulated TCs with modified diurnal periods show similar results. In addition, stronger diurnal signals are observed for stronger vortices, suggesting a dependence of the TC diurnal signal on the underlying state of the vortex. These results imply that the magnitude and structure of the TC diurnal signal in nature varies throughout the storm lifetime, and is a function of the structure and intensity of the vortex.

Interannual Variability of the Patagonian Shelf Circulation and Cross-Shelf Exchange

NASA Astrophysics Data System (ADS)

Combes, V.; Matano, R. P.

2016-02-01

Observational studies have already established the general mean circulation and hydrographic characteristics of the Patagonian shelf waters using data from in situ observation, altimetry and more recently from the Aquarius satellite sea surface salinity, but the paucity of those data in time or below the surface leave us with an incomplete picture of the shelf circulation and of its variability. This study discusses the variability of the Patagonian central shelf circulation and off-shelf transport using a high-resolution model experiment for the period 1979-2012. The model solution shows high skill in reproducing the best-known aspects of the shelf and deep-ocean circulations. This study links the variability of the central shelf circulation and off-shelf transport to the wind variability, southern shelf transport variability and large-scale current variability. We find that while the inner and central shelf circulation are principally wind driven, the contribution of the Brazil/Malvinas Confluence (BMC) variability becomes important in the outer shelf and along the shelf break. The model also indicates that whereas the location of the off-shelf transport is controlled by the BMC, its variability is modulated by the southern shelf transport. The variability of the subtropical shelf front, where the fresh southern shelf waters encounters the saline northern shelf waters, is also presented in this study.

Circulation in the mesosphere and lower thermosphere during the MAP (Middle Atmosphere Program)/WINE (Winter in the Northern Europe) period

NASA Technical Reports Server (NTRS)

Tarasenko, D. A.

1987-01-01

One of the scientific programs in the MAP project, Winter in the Northern Europe (WINE) 1983 to 1984 involved an analysis of circulation processes in the middle atmosphere which characterized that winter period. Rocket soundings were conducted at many stations. In order to investigate deviations of the mean winds for the MAP/WINE period from the circulation conditions of other winters and from the climatic norm, rocket sounding data of Churchill and Barrow stations was well as the Pressure Modulated Radiometer channel 3000 data enabled the compilation of geopotential fields and the calculation of winds in the geostrophic approximation for comparison with the meteor winds. The large scale processes of the winter which determined the circulation in the period of the experiment were analyzed briefly. The analysis and results are discussed.

[Effects of self-foot reflexology on stress, fatigue and blood circulation in premenopausal middle-aged women].

PubMed

Jang, Soo Hyun; Kim, Kye Ha

2009-10-01

This study was to examine the effects of self-foot reflexology on stress, fatigue and blood circulation in premenopausal middle-aged women. A quasi-experimental nonequivalent control group, pretest-posttest design was used. Participants were 59 premenopausal, middle-aged women in their 40s and 60s living in G city: 30 in the experiment group and 29 in the control group. Data were collected from May to August 2008. Self-foot reflexology was performed three times a week for 6 weeks for 40 min at each session. The results showed that self-foot reflexology was effective in reducing perceived stress and fatigue and helped blood circulation in premenopausal middle-aged women. Self-foot reflexology may be an effective nursing intervention in reducing perceived stress and fatigue and in improving blood circulation.

Use of ACE inhibitors in Fontan: Rational or irrational?

PubMed

Wilson, Thomas G; Iyengar, Ajay J; Winlaw, David S; Weintraub, Robert G; Wheaton, Gavin R; Gentles, Thomas L; Ayer, Julian; Grigg, Leeanne E; Justo, Robert N; Radford, Dorothy J; Bullock, Andrew; Celermajer, David S; Dalziel, Kim; Schilling, Chris; d'Udekem, Yves

2016-05-01

Despite a lack of evidence supporting the use of angiotensin-converting enzyme (ACE) inhibitors in patients with a Fontan circulation, their use is frequent. We decided to identify the rationale for ACE inhibitor therapy in patients within the Australia and New Zealand Fontan Registry. All patients in the Registry taking an ACE inhibitor at last follow up were identified, and a review of medical records was undertaken to determine the rationale for treatment initiation and reasons for treatment continuation or dose increase. In 2015, 36% of the surviving patients in the Registry (462/1268) were taking an ACE inhibitor. Indications for initiation of therapy were ventricular systolic or diastolic dysfunction (29%), atrioventricular valve regurgitation (19%), preservation of normal ventricular function (7%), prolonged effusions at Fontan (6%), hypertension (6%), other (6%) and unknown (2%). No indication was stated in the remaining patients (25%). Those with hypoplastic left heart syndrome were more likely to be on an ACE inhibitor than those with an alternative primary morphology (70% vs 32%; p<0.001). Only 36% of the patients treated with an ACE inhibitor at last follow up (166/462) had an indication that would generally justify treatment in a two-ventricle circulation. It is likely that the use of ACE inhibitors in patients with a Fontan circulation is excessive within our region. The coordination of prospective, multicentre studies and initiatives such as the Australia and New Zealand Fontan Registry will facilitate further investigations to guide treatment decisions in the growing Fontan population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Extending the NASA Ames Mars General Circulation Model to Explore Mars’ Middle Atmosphere

NASA Astrophysics Data System (ADS)

Brecht, Amanda; Hollingsworth, J.; Kahre, M.; Schaeffer, J.

2013-10-01

The NASA Ames Mars General Circulation Model (MGCM) upper boundary has been extended to ~120 km altitude (p ~10-5 mbar). The extension of the MGCM upper boundary initiates the ability to understand the connection between the lower and upper atmosphere of Mars through the middle atmosphere 70 - 120 km). Moreover, it provides the opportunity to support future missions (i.e. the 2013 MAVEN mission). A major factor in this extension is the incorporation of the Non-Local Thermodynamic Equilibrium (NLTE) heating (visible) and cooling (infrared). This modification to the radiative transfer forcing (i.e., RT code) has been significantly tested in a 1D vertical column and now has been ported to the full 3D Mars GCM. Initial results clearly show the effects of NLTE in the upper middle atmosphere. Diagnostic of seasonal mean fields and large-scale wave activity will be shown with insight into circulation patterns in the middle atmosphere. Furthermore, sensitivity tests with the resolution of the pressure and temperature grids, in which the k-coefficients are calculated upon, have been performed in the 1D RT code. Our progress on this research will be presented. Brecht is supported by NASA’s Postdoctoral Program at the Ames Research Center, administered by Oak Ridge Associated Universities through a contract with NASA.

Numerical simulations of a transverse indirect circulation and low-level jet in the exit region of an upper-level jet

NASA Technical Reports Server (NTRS)

Brill, K. F.; Uccellini, L. W.; Burkhart, R. P.; Warner, T. T.; Anthes, R. A.

1985-01-01

A numerical study was performed of a severe weather event (tornado) which occurred on May 10, 1973 in the Ohio region. The situation was modeled with a primitive equation mesoscale dynamic formulation. Account was taken of precipitation, the planetary boundary layer parameters as bulk quantities, the vertical pressure gradient, and lateral boundary conditions based on radiosonde data. Two 12-hr simulations, adiabatic and nondivergent, respectively, were analyzed for relationships between upper and lower level jets. In the adiabatic formulation, a transverse circulation with a low level jet formed at the exit region of the upper level jet. The nondivergent situation led to similar, but weaker, phenomena. Both forms suggest that indirect circulation in the exit zone of an upper level jet is strongly influenced by the initial structure of the jet.

Rapid evolution of a jet streak circulation in a pre-convective environment

NASA Technical Reports Server (NTRS)

Kocin, P. J.; Uccellini, L. W.; Petersen, R. A.

1986-01-01

An analysis of the April 10, 1979 Red River Valley severe weather outbreak, using a three-hourly rawinsonde network, indicates that the preconvection environment is influenced by upper-level and lower-level tropospheric jet streaks (ULJs and LLJs) that act to destabilize the atmosphere, and contribute to low-level heat and moisture transports and convergence that act to initiate the storm system. Transformation of an indirect circulation noted within the exit region of the ULJ at 1200 and 1500 GMT is observed within a six-hour period. Dramatic changes are found in the jet streak circulations over a short period of time as the system deviates from that approximated by the geostrophic momentum approximation, and these deviations suggest that adjustments asssociated with ULJs in this case could not be resolved using a simplified two-dimensional approach.

The Arctic Predictability and Prediction on Seasonal-to-Interannual TimEscales (APPOSITE) data set version 1

NASA Astrophysics Data System (ADS)

Day, Jonathan J.; Tietsche, Steffen; Collins, Mat; Goessling, Helge F.; Guemas, Virginie; Guillory, Anabelle; Hurlin, William J.; Ishii, Masayoshi; Keeley, Sarah P. E.; Matei, Daniela; Msadek, Rym; Sigmond, Michael; Tatebe, Hiroaki; Hawkins, Ed

2016-06-01

Recent decades have seen significant developments in climate prediction capabilities at seasonal-to-interannual timescales. However, until recently the potential of such systems to predict Arctic climate had rarely been assessed. This paper describes a multi-model predictability experiment which was run as part of the Arctic Predictability and Prediction On Seasonal to Interannual Timescales (APPOSITE) project. The main goal of APPOSITE was to quantify the timescales on which Arctic climate is predictable. In order to achieve this, a coordinated set of idealised initial-value predictability experiments, with seven general circulation models, was conducted. This was the first model intercomparison project designed to quantify the predictability of Arctic climate on seasonal to interannual timescales. Here we present a description of the archived data set (which is available at the British Atmospheric Data Centre), an assessment of Arctic sea ice extent and volume predictability estimates in these models, and an investigation into to what extent predictability is dependent on the initial state. The inclusion of additional models expands the range of sea ice volume and extent predictability estimates, demonstrating that there is model diversity in the potential to make seasonal-to-interannual timescale predictions. We also investigate whether sea ice forecasts started from extreme high and low sea ice initial states exhibit higher levels of potential predictability than forecasts started from close to the models' mean state, and find that the result depends on the metric. Although designed to address Arctic predictability, we describe the archived data here so that others can use this data set to assess the predictability of other regions and modes of climate variability on these timescales, such as the El Niño-Southern Oscillation.

Multiple causes of the Younger Dryas cold period: new insights from coupled model experiments constrained by data assimilation

NASA Astrophysics Data System (ADS)

Renssen, Hans; Mairesse, Aurélien; Goosse, Hugues; Mathiot, Pierre; Heiri, Oliver; Roche, Didier M.; Nisancioglu, Kerim H.; Valdes, Paul J.

2016-04-01

The Younger Dryas cooling event disrupted the overall warming trend in the North Atlantic region during the last deglaciation. Climate change during the Younger Dryas was abrupt, and thus provides insights into the sensitivity of the climate system to perturbations. The sudden Younger Dryas cooling has traditionally been attributed to a shut-down of the Atlantic meridional overturning circulation by meltwater discharges. However, alternative explanations such as strong negative radiative forcing and a shift in atmospheric circulation have also been offered. In this study we investigate the importance of these different forcings in coupled climate model experiments constrained by data assimilation. We find that the Younger Dryas climate signal as registered in proxy evidence is best simulated using a combination of processes: a weakened Atlantic meridional overturning circulation, moderate negative radiative forcing and an altered atmospheric circulation. We conclude that none of the individual mechanisms alone provide a plausible explanation for the Younger Dryas cold period. We suggest that the triggers for abrupt climate changes like the Younger Dryas are more complex than suggested so far, and that studies on the response of the climate system to perturbations should account for this complexity. Reference: Renssen, H. et al. (2015) Multiple causes of the Younger Dryas cold period. Nature Geoscience 8, 946-949.

Stratospheric General Circulation with Chemistry Model (SGCCM)

NASA Technical Reports Server (NTRS)

Rood, Richard B.; Douglass, Anne R.; Geller, Marvin A.; Kaye, Jack A.; Nielsen, J. Eric; Rosenfield, Joan E.; Stolarski, Richard S.

1990-01-01

In the past two years constituent transport and chemistry experiments have been performed using both simple single constituent models and more complex reservoir species models. Winds for these experiments have been taken from the data assimilation effort, Stratospheric Data Analysis System (STRATAN).

Simulation of a small cold-leg-break experiment at the PMK-2 test facility using the RELAP5 and ATHLET codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ezsoel, G.; Guba, A.; Perneczky, L.

Results of a small-break loss-of-coolant accident experiment, conducted on the PMK-2 integral-type test facility are presented. The experiment simulated a 1% break in the cold leg of a VVER-440-type reactor. The main phenomena of the experiment are discussed, and in the case of selected events, a more detailed interpretation with the help of measured void fraction, obtained by a special measurement device, is given. Two thermohydraulic computer codes, RELAP5 and ATHLET, are used for posttest calculations. The aim of these calculations is to investigate the code capability for modeling natural circulation phenomena in VVER-440-type reactors. Therefore, the results of themore » experiment and both calculations are compared. Both codes predict most of the transient events well, with the exception that RELAP5 fails to predict the dryout period in the core. In the experiment, the hot- and cold-leg loop-seal clearing is accompanied by natural circulation instabilities, which can be explained by means of the ATHLET calculation.« less

Soil Moisture and the Persistence of North American Drought.

NASA Astrophysics Data System (ADS)

Oglesby, Robert J.; Erickson, David J., III

1989-11-01

We describe numerical sensitivity experiments exploring the effects of soil moisture on North American summertime climate using the NCAR CCMI, a 12-layer global atmospheric general circulation model. In particular. the hypothesis that reduced soil moisture may help induce and amplify warm, dry summers over midlatitude continental interiors is examined. Equilibrium climate statistics are computed for the perpetual July model response to imposed soil moisture anomalies over North America between 36° and 49°N. In addition, the persistence of imposed soil moisture anomalies is examined through use of the seasonal cycle mode of operation with use of various initial atmospheric states both equilibrated and nonequilibrated to the initial soil moisture anomaly.The climate statistics generated by thew model simulations resemble in a general way those of the summer of 1988, when extensive heat and drought occurred over much of North America. A reduction in soil moisture in the model leads to an increase in surface temperature, lower surface pressure, increased ridging aloft, and a northward shift of the jet stream. Low-level moisture advection from the Gulf of Mexico is important in determining where persistent soil moisture deficits can be maintained. In seasonal cycle simulations, it lock longer for an initially unequilibrated atmosphere to respond to the imposed soil moisture anomaly, via moisture transport from the Gulf of Mexico, than when initially the atmosphere was in equilibrium with the imposed anomaly., i.e., the initial state was obtained from the appropriate perpetual July simulation. The results demonstrate the important role of soil moisture in prolonging and/or amplifying North American summertime drought.

On the Origin of Monsoon

NASA Technical Reports Server (NTRS)

Chao, Winston C.; Chen, Baode

2000-01-01

The notion that the continental-scale land-sea contrast is the main reason that monsoon circulation exists has been a long-held belief. The purpose of this paper is to point out that this notion should be substantially modified. The central idea of this notion states that in summer, radiative heating of the continent, say Asia, gives rise to a continental-scale thermal low and surrounding the thermal low in its southeast direction the low level wind flows in from south-west. This low-level inflow creates a convergence of moisture, which maintains the cumulus convection. And in winter, radiative cooling of continent gives rise to a thermal high and to its southeast the low-level wind is from northeast. The mechanism in this interpretation does undoubtedly exist. However, this mechanism, though believed to be the main driving force of monsoon, has not been tested in numerical experiments. There has been an increasing recognition in the recent years that monsoon is inextricably tied to the heating in the intertropical convergence zone (ITCZ). We propose that the main cause of monsoon is ITCZ's being substantially away from the equator. A brief qualitative explanation of why the ITCZ can be a source of monsoon circulation can be offered based on the circulation field forced by the ITCZ heating. The existence of the ITCZ's does not always have to rely on land-sea contrast on the continental scale. This is hinted in the fact that in February the ITCZ close to Australia (and its associated monsoon circulation) covers a longitudinal range several times as long as that of Australia and thus cannot possibly be caused mainly by the land-sea contrast associated with Australia. Yet, this cannot be used as a proof that the ITCZ in the Asian summer monsoon is not mainly due to land-sea contrast. One of the purposes of this work is to provide a convincing proof. In this work the role of land-sea contrast in the origin of monsoon is examined through numerical simulation with the Goddard general circulation model. The Asian and Australian monsoon circulations are obtained in a four-year integration and then the integration is repeated with Asia, the maritime continent, and Australia replaced by ocean. The sea surface temperature (SST) at each affected grid is specified as the SST at the first grid to the east that is an ocean grid in the first experiment. The latter integration shows that the monsoon circulation pattern over where south Asia and Australia were and the surrounding region has largely remained. The results discount land-sea contrast as the main cause of Asian monsoon. A third experiment is the same as the first except that the topography of Asia, the maritime continent, and Australia is reduced to zero. This experiment reveals that the difference between the first two experiments is due more to the removal of topography than to the removal of land-sea contrast. August precipitation is shown averaged over the last three years of each of the three experiments. They show that the Asian monsoon rainy region is largely intact in the second experiment and the difference between the second and the third experiment is mainly in the longitudinal location of the maximum precipitation. Additionally, in Asian and Australian winter monsoons land-sea contrast also plays only a modifying role. Although land-sea contrast plays only a modifying role in Asian and Australian (and Central American including Mexican) monsoons, it is the main reason that ITCZ (and thus monsoon) exists in Africa and South America. Thus, monsoons can be classified into two groups depending on whether land-sea contrast plays a major role.

Dispersal and transport of river sediment on the Catalan Shelf (NW Mediterranean Sea).

NASA Astrophysics Data System (ADS)

Grifoll, Manel; Gracia, Vicente; Espino, Manuel; Sánchez-Arcilla, Agustín

2014-05-01

A three-dimensional coupled hydrodynamics-sediment transport model for the Catalan shelf (NW Mediterranean Sea) is implemented and used to represent the fluvial sediment transport and depositional patterns. The modelling system COAWST (Warner et al., 2010) allows to exchange field from the water circulation model ROMS and the wave model SWAN including combined wave-current bed stress and both sediment transport mechanisms: bed and suspended load. Two rivers surrounding Barcelona harbour are considered in the numerical experiments. Different temporal and spatial scales are modelled in order to evaluate physical mechanisms such as: fine deposits formation in the inner-shelf, harbour siltation or sediment exporting to the outer shelf. Short-time simulations in a high-resolution mesh have been used to reproduce the initial stages of the sediment dispersal. In this case, sediment accumulation occurs confined in an area attached to the coastline. A subsequent reworking is observed due to the wave-induced bottom stresses which resuspend fine material exported then towards the mid-shelf by seawards fluxes. The long-term water circulation simulations explains the observed fine deposits over the shelf. The results provide knowledge of sediment transport processes in the near-shore area of a micro-tidal domain. REFERENCES: Warner, J.C., Armstrong, B., He, R., and Zambon, J.B., 2010, Development of a Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system: Ocean Modeling, v. 35, no. 3, p. 230-244.

Porosity evolution at the brittle-ductile transition in the continental crust: Implications for deep hydro-geothermal circulation.

PubMed

Violay, M; Heap, M J; Acosta, M; Madonna, C

2017-08-09

Recently, projects have been proposed to engineer deep geothermal reservoirs in the ductile crust. To examine their feasibility, we performed high-temperature (up to 1000 °C), high-pressure (130 MPa) triaxial experiments on granite (initially-intact and shock-cooled samples) in which we measured the evolution of porosity during deformation. Mechanical data and post-mortem microstuctural characterisation (X-ray computed tomography and scanning electron microscopy) indicate that (1) the failure mode was brittle up to 900 °C (shear fracture formation) but ductile at 1000 °C (no strain localisation); (2) only deformation up to 800 °C was dilatant; (3) deformation at 900 °C was brittle but associated with net compaction due to an increase in the efficiency of crystal plastic processes; (4) ductile deformation at 1000 °C was compactant; (5) thermally-shocking the granite did not influence strength or failure mode. Our data show that, while brittle behaviour increases porosity, porosity loss is associated with both ductile behaviour and transitional behaviour as the failure mode evolves from brittle to ductile. Extrapolating our data to geological strain rates suggests that the brittle-ductile transition occurs at a temperature of 400 ± 100 °C, and is associated with the limit of fluid circulation in the deep continental crust.

A Study of the December 1992 Westerly Wind Burst Event during TOGA COARE

NASA Technical Reports Server (NTRS)

Chen, Chaing; Tao, Wei-Kuo; Duffy, Dean G.; Lai, George S.; Lin, Po-Hsiung

1999-01-01

Using the Penn State/NCAR MM5 mesoscale model, a westerly wind burst (WWB) that occurred during the period from 19 to 30 December 1992 over the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) has been simulated and compared with observation. This event is characterized by the presence of super cloud clusters and the occurrence of a major WWB that extended over the western and central Pacific Ocean. Although several of the observed convective systems were not precisely simulated by MM5, the model did capture many other observed characteristics, such as the explosive development of convection, the cyclonic circulation and the WWB. The WWB resulted from the coalescence of three types of tropical disturbances. The first type was a low-level westerly jet (LWJ) that developed at the equator and may be associated with the eastward propagation of an ISO (Intraseasonal Oscillation). The second type featured an easterly wave-like disturbance that originated in the south central Pacific Ocean and propagated westward. Finally, the third type involved a cross-equatorial flow that deflected Northern Hemispheric easterlies into the Southern Hemisphere and may be caused by inertial instability. These disturbances worked in concert, resulting in intense convection over the TOGA COARE region. Once intense convection developed, a large-scale circulation was produced over the western Pacific warm pool, propagated eastward, and initiated a WWB.

The mechanism of muscle injury in the crush syndrome: ischemic versus pressure-stretch myopathy.

PubMed

Better, O S; Abassi, Z; Rubinstein, I; Marom, S; Winaver, Y; Silberman, M

1990-01-01

Crush injuries are ubiquitous, common sequelae in victims of seismic, industrial and military catastrophes, and were considered to be mainly due to ischemia of the affected limbs. Our clinical experience suggests that early in the crush syndrome, interference with the circulation may occur but is rare. The predominant earliest lesion in the crush syndrome is postulated to be pressure-stretch myopathy, rather than ischemic myopathy. It is proposed that at the membrane level, stretch increases sarcoplasmic influx of Na, Cl, H2O and Ca down their electrochemical gradient. Energy-requiring cationic extrusion pumps work at maximal capacity, but are unable to cope with the increased load. This results in cell swelling and increase in cytosolic and mitochondrial calcium with activation of autolytic destructive processes and interference with cellular respiration. Extensive muscle swelling may cause late muscle tamponade and myoneural ischemic damage (compartmental syndrome). Thus, whereas prevalent theory suggests that the sarcolemmal cationic pump activity is attenuated in the crush syndrome due to early ischemia, we propose that the cationic extrusion pump is maximally activated as in the amphotericin B model. Because the cationic pump is maximally activated in the stretched muscle and in cells exposed to amphotericin, these models rapidly deplete their scarce ATP stores and are susceptible to hypoxia in the face of initially normal circulation.

Oxidative stress and inflammatory response increase during coronary artery bypass grafting with extracorporeal circulation.

PubMed

Melek, Flora Eli; Baroncini, Liz Andréa Villela; Repka, João Carlos Domingus; Nascimento, Celso Soares; Précoma, Dalton Bertolim

2012-01-01

Thiobarbituric acid-reactive substance is a marker of oxidative stress and has cytotoxic and genotoxic actions. C- reactive protein is used to evaluate the acute phase of inflammatory response. To assess the thiobarbituric acid-reactive substance and C-reactive protein levels during extracorporeal circulation in patients submitted to cardiopulmonary bypass. Twenty-five consecutive surgical patients (16 men and nine women; mean age 61.2 ± 9.7 years) with severe coronary artery disease diagnosed by angiography scheduled for myocardial revascularization surgery with extracorporeal circulation were selected. Blood samples were collected immediately before initializing extracorporeal circulation, T0; in 10 minutes, T10; and in 30 minutes, T30. The thiobarbituric acid-reactive substance levels increased after extracorporeal circulation (P=0.001), with average values in T0=1.5 ± 0.07; in T10=5.54 ± 0.35; and in T30=3.36 ± 0.29 mmoles/mg of serum protein. The C-reactive protein levels in T0 were negative in all samples; in T10 average was 0.96 ± 0.7 mg/dl; and in T30 average was 0.99 ± 0.76 mg/dl. There were no significant differences between the dosages in T10 and T30 (P=0.83). C-reactive protein and thiobarbituric acid-reactive substance plasma levels progressively increased during extracorporeal circulation, with maximum values of thiobarbituric acid-reactive substance at 10 min and of C-reactive protein at 30 min. It suggests that there are an inflammatory response and oxidative stress during extracorporeal circulation.

Rotating-fluid experiments with an atmospheric general circulation model

NASA Technical Reports Server (NTRS)

Geisler, J. E.; Pitcher, E. J.; Malone, R. C.

1983-01-01

In order to determine features of rotating fluid flow that are dependent on the geometry, rotating annulus-type experiments are carried out with a numerical model in spherical coordinates. Rather than constructing and testing a model expressly for this purpose, it is found expedient to modify an existing general circulation model of the atmosphere by removing the model physics and replacing the lower boundary with a uniform surface. A regime diagram derived from these model experiments is presented; its major features are interpreted and contrasted with the major features of rotating annulus regime diagrams. Within the wave regime, a narrow region is found where one or two zonal wave numbers are dominant. The results reveal no upper symmetric regime; wave activity at low rotation rates is thought to be maintained by barotropic rather than baroclinic processes.

Mid-latitude afforestation shifts general circulation and tropical precipitation.

PubMed

Swann, Abigail L S; Fung, Inez Y; Chiang, John C H

2012-01-17

We show in climate model experiments that large-scale afforestation in northern mid-latitudes warms the Northern Hemisphere and alters global circulation patterns. An expansion of dark forests increases the absorption of solar energy and increases surface temperature, particularly in regions where the land surface is unable to compensate with latent heat flux due to water limitation. Atmospheric circulation redistributes the anomalous energy absorbed in the northern hemisphere, in particular toward the south, through altering the Hadley circulation, resulting in the northward displacement of the tropical rain bands. Precipitation decreases over parts of the Amazon basin affecting productivity and increases over the Sahel and Sahara regions in Africa. We find that the response of climate to afforestation in mid-latitudes is determined by the amount of soil moisture available to plants with the greatest warming found in water-limited regions. Mid-latitude afforestation is found to have a small impact on modeled global temperatures and on global CO(2), but regional heating from the increase in forest cover is capable of driving unintended changes in circulation and precipitation. The ability of vegetation to affect remote circulation has implications for strategies for climate mitigation.

Global transport of atmospheric smoke following a major nuclear exchange

NASA Technical Reports Server (NTRS)

Haberle, R. M.; Ackerman, T. P.; Toon, O. B.; Hollingsworth, J. L.

1985-01-01

A fully interactive zonally symmetric general circulation model is used to simulate the transport and evolution of a massive smoke cloud that is likely to form in the atmosphere following a major nuclear war. The presence of such a cloud significantly alters the simulated circulation and the subsequent transport of the smoke particles themselves. While the model indicates a tendency for interhemispheric exchange, the most immediate effect is that the radiatively active particles are carried into the stratosphere by the generation of strong vertical motions and intense convection regardless of their initial injection altitudes.

Global transport of atmospheric smoke following a major nuclear exchange

NASA Astrophysics Data System (ADS)

Haberle, Robert M.; Ackerman, Thomas P.; Toon, Owen B.; Hollingsworth, Jeffery L.

A fully interactive zonally symmetric general circulation model is used to simulate the transport and evolution of a massive smoke cloud that is likely to form in the atmosphere following a major nuclear war. The presence of such a cloud significantly alters the simulated circulation and the subsequent transport of the smoke particles themselves. While the model indicates a tendency for interhemispheric exchange, the most immediate effect is that the radiatively active particles are carried into the stratosphere by the generation of strong vertical motions and intense convection regardless of their initial injection altitudes.

Computer studies of baroclinic flow. [Atmospheric General Circulation Experiment

NASA Technical Reports Server (NTRS)

Gall, R.

1985-01-01

Programs necessary for computing the transition curve on the regime diagram for the atmospheric general circulation experiment (AGOE) were completed and used to determine the regime diagram for the rotating annulus and some axisymmetric flows for one possible AGOE configuration. The effect of geometrical constraints on the size of eddies developing from a basic state is being examined. In AGOE, the geometric constraint should be the width of the shear zone or the baroclinic zone. Linear and nonlinear models are to be used to examine both barotropic and baroclinic flows. The results should help explain the scale selection mechanism of baroclinic eddies in the atmosphere experimental models such as AGOE, and the multiple vortex phenomenon in tornadoes.

Decline of the marine ecosystem caused by a reduction in the Atlantic overturning circulation.

PubMed

Schmittner, Andreas

2005-03-31

Reorganizations of the Atlantic meridional overturning circulation were associated with large and abrupt climatic changes in the North Atlantic region during the last glacial period. Projections with climate models suggest that similar reorganizations may also occur in response to anthropogenic global warming. Here I use ensemble simulations with a coupled climate-ecosystem model of intermediate complexity to investigate the possible consequences of such disturbances to the marine ecosystem. In the simulations, a disruption of the Atlantic meridional overturning circulation leads to a collapse of the North Atlantic plankton stocks to less than half of their initial biomass, owing to rapid shoaling of winter mixed layers and their associated separation from the deep ocean nutrient reservoir. Globally integrated export production declines by more than 20 per cent owing to reduced upwelling of nutrient-rich deep water and gradual depletion of upper ocean nutrient concentrations. These model results are consistent with the available high-resolution palaeorecord, and suggest that global ocean productivity is sensitive to changes in the Atlantic meridional overturning circulation.

The future of spaceborne altimetry. Oceans and climate change: A long-term strategy

NASA Technical Reports Server (NTRS)

Koblinsky, C. J. (Editor); Gaspar, P. (Editor); Lagerloef, G. (Editor)

1992-01-01

The ocean circulation and polar ice sheet volumes provide important memory and control functions in the global climate. Their long term variations are unknown and need to be understood before meaningful appraisals of climate change can be made. Satellite altimetry is the only method for providing global information on the ocean circulation and ice sheet volume. A robust altimeter measurement program is planned which will initiate global observations of the ocean circulation and polar ice sheets. In order to provide useful data about the climate, these measurements must be continued with unbroken coverage into the next century. Herein, past results of the role of the ocean in the climate system is summarized, near term goals are outlined, and requirements and options are presented for future altimeter missions. There are three basic scientific objectives for the program: ocean circulation; polar ice sheets; and mean sea level change. The greatest scientific benefit will be achieved with a series of dedicated high precision altimeter spacecraft, for which the choice of orbit parameters and system accuracy are unencumbered by requirements of companion instruments.

Assimilation of TOPEX/POSEIDON altimeter data into a circulation model of the North Atlantic

NASA Astrophysics Data System (ADS)

Blayo, E.; Verron, J.; Molines, J. M.

1994-12-01

Assimilation experiments were conducted using the first 12 months of TOPEX/POSEIDON (T/P) altimeter measurements in a multilayered quasi-geostrophic model of the North Atlantic between 20°N and 60°N. These experiments demonstrate the feasibility of using T/P data to control a basin-scale circulation model by means of an assimilation procedure. Moreover, they allow us to recreate the four-dimensional behavior of the North Atlantic Ocean during the year October 1992-September 1993 and to improve our knowledge and understanding of such circulation patterns. For this study we used a four-layer quasigeostrophic model of high horizontal resolution (1/6° in latitude and longitude). The assimilation procedure used is an along-track, sequential, nudging technique. The evolution of the model general circulation is described and analyzed from a deterministic and statistical point of view, with special emphasis on the Gulf Stream area. The gross features of the North Atlantic circulation in terms of mean transport and circulation are reproduced, such as the path, penetration and recirculation of the Gulf Stream, and its meandering throughout the eastern basin. The North Atlantic Drift is, however, noticeably underestimated. A northern meander of the north wall of the Gulf Stream above the New England Seamount Chain is present for most of the year, while, just downstream, the southern part of the jet is subject to a 100-km southeastward deflection. The Azores current is shown to remain stable and to shift southward with time from the beginning of December 1992 to the end of April 1993, the amplitude of the shift being about 2°. The computation of the mean latitude of the Gulf Stream as a function of time shows an abrupt shift from a northern position to a southern position in January, and a reverse shift, from a southern position to a northern position, in July. Finally, some issues are addressed concerning the comparison of assimilation experiments using T/P data and Geosat data. The first results show that the T/P simulations are more energetic than the Geosat simulations, especially east of the Mid-Atlantic Ridge, for every wavelength from 50 km to 500 km. This property is also verified in the deep ocean. The predicted abyssal circulation is indeed more energetic in the T/P case, which is more in accordance with what we know of the real ocean. Moreover, the good T/P altimeter coverage near the coasts greatly improves the model eddy kinetic energy levels in these areas, especially east of 25°W.

KSC-03PD-0178

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- The L-1011 aircraft soars through the sky over the Atlantic Ocean with a Pegasus XL rocket, containing NASA's Solar Radiation and Climate Experiment (SORCE), attached underneath. The rocket will be dropped from the aircraft at 3:14 p.m. EST. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

KSC-03PD-0177

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. - The L-1011 aircraft soars through the sky over the Atlantic Ocean with a Pegasus XL rocket, containing NASA's Solar Radiation and Climate Experiment (SORCE), attached underneath. The rocket will be dropped from the aircraft at 3:14 p.m. EST. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

RELAP5 posttest calculation of IAEA-SPE-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petelin, S.; Mavko, B.; Parzer, I.

The International Atomic Energy Agency`s Fourth Standard Problem Exercise (IAEA-SPE-4) was performed at the PMK-2 facility. The PMK-2 facility is designed to study processes following small- and medium-size breaks in the primary system and natural circulation in VVER-440 plants. The IAEA-SPE-4 experiment represents a cold-leg side small break, similar to the IAEA-SPE-2, with the exception of the high-pressure safety injection being unavailable, and the secondary side bleed and feed initiation. The break valve was located at the dead end of a vertical downcomer, which in fact simulates a break in the reactor vessel itself, and should be unlikely to happenmore » in a real nuclear power plant (NPP). Three different RELAP5 code versions were used for the transient simulation in order to assess the calculations with test results.« less

Automation of a portable extracorporeal circulatory support system with adaptive fuzzy controllers.

PubMed

Mendoza García, A; Krane, M; Baumgartner, B; Sprunk, N; Schreiber, U; Eichhorn, S; Lange, R; Knoll, A

2014-08-01

The presented work relates to the procedure followed for the automation of a portable extracorporeal circulatory support system. Such a device may help increase the chances of survival after suffering from cardiogenic shock outside the hospital, additionally a controller can provide of optimal organ perfusion, while reducing the workload of the operator. Animal experiments were carried out for the acquisition of haemodynamic behaviour of the body under extracorporeal circulation. A mathematical model was constructed based on the experimental data, including a cardiovascular model, gas exchange and the administration of medication. As the base of the controller fuzzy logic was used allowing the easy integration of knowledge from trained perfusionists, an adaptive mechanism was included to adapt to the patient's individual response. Initial simulations show the effectiveness of the controller and the improvements of perfusion after adaptation. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

Improved Seasonal Prediction of European Summer Temperatures With New Five-Layer Soil-Hydrology Scheme

NASA Astrophysics Data System (ADS)

Bunzel, Felix; Müller, Wolfgang A.; Dobrynin, Mikhail; Fröhlich, Kristina; Hagemann, Stefan; Pohlmann, Holger; Stacke, Tobias; Baehr, Johanna

2018-01-01

We evaluate the impact of a new five-layer soil-hydrology scheme on seasonal hindcast skill of 2 m temperatures over Europe obtained with the Max Planck Institute Earth System Model (MPI-ESM). Assimilation experiments from 1981 to 2010 and 10-member seasonal hindcasts initialized on 1 May each year are performed with MPI-ESM in two soil configurations, one using a bucket scheme and one a new five-layer soil-hydrology scheme. We find the seasonal hindcast skill for European summer temperatures to improve with the five-layer scheme compared to the bucket scheme and investigate possible causes for these improvements. First, improved indirect soil moisture assimilation allows for enhanced soil moisture-temperature feedbacks in the hindcasts. Additionally, this leads to improved prediction of anomalies in the 500 hPa geopotential height surface, reflecting more realistic atmospheric circulation patterns over Europe.

GLOBEC (Global Ocean Ecosystems Dynamics: Northwest Atlantic program

NASA Technical Reports Server (NTRS)

1991-01-01

The specific objective of the meeting was to plan an experiment in the Northwestern Atlantic to study the marine ecosystem and its role, together with that of climate and physical dynamics, in determining fisheries recruitment. The underlying focus of the GLOBEC initiative is to understand the marine ecosystem as it related to marine living resources and to understand how fluctuation in these resources are driven by climate change and exploitation. In this sense the goal is a solid scientific program to provide basic information concerning major fisheries stocks and the environment that sustains them. The plan is to attempt to reach this understanding through a multidisciplinary program that brings to bear new techniques as disparate as numerical fluid dynamic models of ocean circulation, molecular biology and modern acoustic imaging. The effort will also make use of the massive historical data sets on fisheries and the state of the climate in a coordinated manner.

KSC-03pd0178

NASA Image and Video Library

2003-01-25

KENNEDY SPACE CENTER, FLA. -- The L-1011 aircraft soars through the sky over the Atlantic Ocean with a Pegasus XL rocket, containing NASA's Solar Radiation and Climate Experiment (SORCE), attached underneath. The rocket will be dropped from the aircraft at 3:14 p.m. EST. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

KSC-03pd0177

NASA Image and Video Library

2003-01-25

KENNEDY SPACE CENTER, FLA. - The L-1011 aircraft soars through the sky over the Atlantic Ocean with a Pegasus XL rocket, containing NASA's Solar Radiation and Climate Experiment (SORCE), attached underneath. The rocket will be dropped from the aircraft at 3:14 p.m. EST. Over the next few days, the mission team will insure that the spacecraft is functioning properly. The SORCE science instruments will then be turned on and their health verified. Approximately 21 days after launch, if all is going well, the instruments will start initial science data collection and calibration will begin. The spacecraft will study the Sun's influence on our Earth and will measure from space how the Sun affects the Earth's ozone layer, atmospheric circulation, clouds, and oceans. This mission is a joint partnership between NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, Colorado. [Photo courtesy of Jeff Caplan, Langley Research

Utilization of a New Intracranial Support Catheter as an Intermediate Aspiration Catheter in the Treatment of Acute Ischemic Stroke: Technical Report on Initial Experience.

PubMed

Lozano, J Diego; Massari, Francesco; Howk, Mary C; de Macedo Rodrigues, Katyucia; Brooks, Christopher; Perras, Mary; Rex, David E; Wakhloo, Ajay K; Kühn, Anna Luisa; Puri, Ajit S

2016-05-21

The endovascular management of acute ischemic stroke (AIS) due to emergency large vessel occlusion (ELVO) has become the standard of care after the recent publication of landmark randomized, controlled trials. Mechanical thrombectomy, in addition to intravenous thrombolysis (within 4.5 hours when eligible), is now part of the algorithm of the standard of care when treating AIS in patients with ELVO in the anterior circulation up to six hours after symptom onset. A newly introduced device, the Arc™ intracranial support catheter (Medtronic, Irvine, USA), is specifically designed for the introduction of neurointerventional devices into the cerebral vasculature and facilitates the delivery of microcatheters into smaller, more distal intracranial vessels. This technical report describes the use of the Arc™ intracranial support catheter in the setting of AIS.

Utilization of a New Intracranial Support Catheter as an Intermediate Aspiration Catheter in the Treatment of Acute Ischemic Stroke: Technical Report on Initial Experience

PubMed Central

Lozano, J. Diego; Massari, Francesco; Howk, Mary C; de Macedo Rodrigues, Katyucia; Brooks, Christopher; Perras, Mary; Rex, David E; Wakhloo, Ajay K; Kühn, Anna Luisa

2016-01-01

The endovascular management of acute ischemic stroke (AIS) due to emergency large vessel occlusion (ELVO) has become the standard of care after the recent publication of landmark randomized, controlled trials. Mechanical thrombectomy, in addition to intravenous thrombolysis (within 4.5 hours when eligible), is now part of the algorithm of the standard of care when treating AIS in patients with ELVO in the anterior circulation up to six hours after symptom onset. A newly introduced device, the Arc™ intracranial support catheter (Medtronic, Irvine, USA), is specifically designed for the introduction of neurointerventional devices into the cerebral vasculature and facilitates the delivery of microcatheters into smaller, more distal intracranial vessels. This technical report describes the use of the Arc™ intracranial support catheter in the setting of AIS. PMID:27382525

Vascular Endothelial Growth Factor (VEGF) mRNA Isoforms are Altered in Bovine Granulosa Cells (GC) by Circulating Progestin Concentrations (P4) and May Indicate Follicle Status and Oocyte Competence

USDA-ARS?s Scientific Manuscript database

Previously, Melengestrol Acetate (MGA) fed for 14 d (0.5mg/cow/d; < 1 ng/ml P4) resulted in persistent follicles with increased size, decreased number of GC/follicular fluid (FF) volume, and less fertile oocytes. An experiment was conducted to determine effects of circulating P4 on amount of mRNA fo...

Flow dynamics and salt transport in a coastal aquifer driven by a stratified saltwater body: Lab experiment and numerical modeling

NASA Astrophysics Data System (ADS)

Oz, Imri; Shalev, Eyal; Yechieli, Yoseph; Gavrieli, Ittai; Gvirtzman, Haim

2014-04-01

This paper examines the transient development and the steady-state configuration of groundwater within a coastal aquifer adjacent to a stratified saltwater body. Such systems consist of three different water types: the regional fresh groundwater, and low and high salinity brines forming the upper and lower water layers of the stratified water body, respectively. The dynamics, location and the geometry of the interfaces and the density-driven circulation flows that develop in the aquifer are examined using laboratory experiments and numerical modeling at the same scale. The results show that the transient intrusion of the different water bodies into the aquifer takes place at different rates, and that the locations of the interfaces between them change with time, before reaching steady-state. Under steady-state conditions both the model and the experiments show the existence of three interfaces between the three water types. The numerical model, which is calibrated against the salinity distribution and groundwater discharge rate in the laboratory experiments, allows the quantification of the flow rates and flow patterns within the aquifer. These flow patterns, which cannot be derived from laboratory experiments, show the transient development of three circulation cells which are confined between the three interfaces. These results confirm the hypothesis that has been previously suggested based solely on a steady-state numerical modeling defined by a conceptual understanding. Parametric analysis shows that the creation of three circulation cells and three interfaces is limited to certain conditions and defines the ranges for the creation of this unique system.

Optimization of Progressive Freeze Concentration on Apple Juice via Response Surface Methodology

NASA Astrophysics Data System (ADS)

Samsuri, S.; Amran, N. A.; Jusoh, M.

2018-05-01

In this work, a progressive freeze concentration (PFC) system was developed to concentrate apple juice and was optimized by response surface methodology (RSM). The effects of various operating conditions such as coolant temperature, circulation flowrate, circulation time and shaking speed to effective partition constant (K) were investigated. Five different level of central composite design (CCD) was employed to search for optimal concentration of concentrated apple juice. A full quadratic model for K was established by using method of least squares. A coefficient of determination (R2) of this model was found to be 0.7792. The optimum conditions were found to be coolant temperature = -10.59 °C, circulation flowrate = 3030.23 mL/min, circulation time = 67.35 minutes and shaking speed = 30.96 ohm. A validation experiment was performed to evaluate the accuracy of the optimization procedure and the best K value of 0.17 was achieved under the optimized conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Zhun; Zhou, Tianjun; Wang, Minghuai

The impacts of cloud radiative heating on East Asian Summer Monsoon (EASM) over the southeastern China (105°-125°E, 20°-35°N) are explained by using the Community Atmosphere Model version 5 (CAM5). Sensitivity experiments demonstrate that the radiative heating of clouds leads to a positive effect on the local EASM circulation over southeastern China. Without the radiative heating of cloud, the EASM circulation and precipitation would be much weaker than that in the normal condition. The longwave heating of clouds dominates the changes of EASM circulation. The positive effect of clouds on EASM circulation is explained by the thermodynamic energy equation, i.e. themore » different heating rate between cloud base and cloud top enhances the convective instability over southeastern China, which enhances updraft consequently. The strong updraft would further result in a southward meridional wind above the center of the updraft through Sverdrup vorticity balance.« less

Circulating AST, H-FABP, and NGAL are early and accurate biomarkers of graft injury and dysfunction in a preclinical model of kidney transplantation.

PubMed

Jochmans, Ina; Lerut, Evelyne; van Pelt, Jos; Monbaliu, Diethard; Pirenne, Jacques

2011-11-01

To investigate circulating biomarkers of initial graft injury in a porcine kidney autotransplant model. Injury endured by kidney grafts early posttransplant determines their outcome. However, creatinine (clearance) is a poor surrogate of tissue injury and urinary biomarkers are limited by graft anuria or persistent native kidney diuresis. No validated circulating biomarkers quantifying initial graft injury exist. Minimally injured porcine kidney grafts (n = 6) were cold stored (18 hours) and autotransplanted. Moderately (n = 6) and severely injured grafts (n = 7) were exposed to 30 or 60 minutes warm ischemia before storage and autotransplantation. Four biomarkers [aspartate transaminase (AST), heart-type fatty acid-binding protein (H-FABP), neutrophil gelatinase-associated lipocalin (NGAL), and N-acetyl-β-glucosaminidase (NAG)] were measured posttransplant and compared with creatinine (clearance) and histology. Diuresis was delayed in moderately [2.5 days (2-3)] and severely [4 days (4-5)] versus minimally injured grafts (P < 0.001). Creatinine peaked later than AST, H-FABP, and NGAL [4 days (3-5) vs 3 hours (3-6), 6 hours (6-24), 2 days (1-3), respectively] and only differentiated minimally from severely injured grafts. Peak AST and H-FABP distinguished all injury grades. Neutrophil gelatinase-associated lipocalin discriminated initial graft injury 2 days posttransplant. Peak AST, H-FABP, and NGAL correlated with peak creatinine [Pearson coefficients: 0.70 (P = 0.001), 0.85 (P < 0.0001), 0.80 (P < 0.0001)]. N-acetyl-β-glucosaminidase was not different. Decreased clearance accounted for a small percentage of H-FABP and NGAL increase. Histology was not different among transplanted groups. Plasma AST, H-FABP, and NGAL reflect the severity of initial kidney graft injury and predict graft dysfunction earlier and more accurately than creatinine (clearance) and histology. They represent promising tools to improve patient care after kidney transplantation.

Transmissibility and persistence of oral polio vaccine viruses: implications for the global poliomyelitis eradication initiative.

PubMed

Fine, P E; Carneiro, I A

1999-11-15

The global poliomyelitis eradication initiative has been a tremendous success, with current evidence suggesting that wild poliovirus will cease to circulate anywhere in the world soon after the year 2000. As the goal of wild poliovirus eradication is approached, concern has been raised about the potential for persistent transmission of oral polio vaccine (OPV) viruses, as these viruses are known to revert toward wild-type neurovirulence. This paper has been extracted from a document prepared for the World Health Organization on the implications of OPV transmissibility for the strategy of stopping OPV vaccination after global eradication of wild polioviruses. The authors review the empirical evidence on OPV transmissibility available from household and community transmission studies and from mass-vaccination experiences. They then consider theoretical measures of transmissibility and persistence for wild and OPV viruses (secondary attack rate, basic reproduction number, and critical populations' size), to assess whether transmissibility of OPV viruses is sufficient to allow persistence of these viruses after cessation of vaccination. The findings indicate that OPV viruses could persist under various plausible circumstances, and that this potential should be a major consideration when planning the cessation of OPV vaccination.

Use of the 1991 ASCOT field study data in a mesoscale model employing a four-dimensional data assimilation technique

NASA Astrophysics Data System (ADS)

Fast, Jerome D.; Osteen, B. Lance

In this study, a four-dimensional data assimilation technique based on Newtonian relaxation is incorporated into the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) and evaluated using data taken from one experiment of the US Department of Energy's (DOE) 1991 Atmospheric Studies in COmplex Terrain (ASCOT) field study along the front range of the Rockies in Colorado. The main objective of this study is to determine the ability of the model to predict small-scale circulations influenced by terrain, such as drainage flows, and assess the impact of data assimilation on the numerical results. In contrast to previous studies in which the smallest horizontal grid spacing was 10 km and 8 km, data assimilation is applied in this study to domains with a horizontal grid spacing as small as 1 km. The prognostic forecasts made by RAMS are evaluated by comparing simulations that employ static initial conditions, with simulations that incorporate continuous data assimilation, and data assimilation for a fixed period of time (dynamic initialization). This paper will also elaborate on the application and limitation of the Newtonian relaxation technique in limited-area mesoscale models with a relatively small grid spacing.

A mixed pseudospectral/finite difference method for the axisymmetric flow in a heated, rotating spherical shell. [for experimental atmospheric simulation

NASA Technical Reports Server (NTRS)

Macaraeg, M. G.

1986-01-01

For a Spacelab flight, a model experiment of the earth's atmospheric circulation has been proposed. This experiment is known as the Atmospheric General Circulation Experiment (AGCE). In the experiment concentric spheres will rotate as a solid body, while a dielectric fluid is confined in a portion of the gap between the spheres. A zero gravity environment will be required in the context of the simulation of the gravitational body force on the atmosphere. The present study is concerned with the development of pseudospectral/finite difference (PS/FD) model and its subsequent application to physical cases relevant to the AGCE. The model is based on a hybrid scheme involving a pseudospectral latitudinal formulation, and finite difference radial and time discretization. The advantages of the use of the hybrid PS/FD method compared to a pure second-order accurate finite difference (FD) method are discussed, taking into account the higher accuracy and efficiency of the PS/FD method.

Three-dimensional computer model for the atmospheric general circulation experiment

NASA Technical Reports Server (NTRS)

Roberts, G. O.

1984-01-01

An efficient, flexible, three-dimensional, hydrodynamic, computer code has been developed for a spherical cap geometry. The code will be used to simulate NASA's Atmospheric General Circulation Experiment (AGCE). The AGCE is a spherical, baroclinic experiment which will model the large-scale dynamics of our atmosphere; it has been proposed to NASA for future Spacelab flights. In the AGCE a radial dielectric body force will simulate gravity, with hot fluid tending to move outwards. In order that this force be dominant, the AGCE must be operated in a low gravity environment such as Spacelab. The full potential of the AGCE will only be realized by working in conjunction with an accurate computer model. Proposed experimental parameter settings will be checked first using model runs. Then actual experimental results will be compared with the model predictions. This interaction between experiment and theory will be very valuable in determining the nature of the AGCE flows and hence their relationship to analytical theories and actual atmospheric dynamics.

Physiological levels of blood coagulation factors IX and X control coagulation kinetics in an in vitro model of circulating tissue factor

NASA Astrophysics Data System (ADS)

Tormoen, Garth W.; Khader, Ayesha; Gruber, András; McCarty, Owen J. T.

2013-06-01

Thrombosis significantly contributes to cancer morbidity and mortality. The mechanism behind thrombosis in cancer may be circulating tissue factor (TF), as levels of circulating TF are associated with thrombosis. However, circulating TF antigen level alone has failed to predict thrombosis in patients with cancer. We hypothesize that coagulation factor levels regulate the kinetics of circulating TF-induced thrombosis. Coagulation kinetics were measured as a function of individual coagulation factor levels and TF particle concentration. Clotting times increased when pooled plasma was mixed at or above a ratio of 4:6 with PBS. Clotting times increased when pooled plasma was mixed at or above a ratio of 8:2 with factor VII-depleted plasma, 7:3 with factor IX- or factor X-depleted plasmas, or 2:8 with factor II-, V- or VIII-depleted plasmas. Addition of coagulation factors VII, X, IX, V and II to depleted plasmas shortened clotting and enzyme initiation times, and increased enzyme generation rates in a concentration-dependent manner. Only additions of factors IX and X from low-normal to high-normal levels shortened clotting times and increased enzyme generation rates. Our results demonstrate that coagulation kinetics for TF particles are controlled by factor IX and X levels within the normal physiological range. We hypothesize that individual patient factor IX and X levels may be prognostic for susceptibility to circulating TF-induced thrombosis.

Impacts of initial convective structure on subsequent squall line evolution

NASA Astrophysics Data System (ADS)

Varble, A.; Morrison, H.; Zipser, E. J.

2017-12-01

A Weather Research and Forecasting simulation of the 20 May 2011 MC3E squall line using 750-m horizontal grid spacing produces wide convective regions with strongly upshear tilted convective updrafts and mesoscale bowing segments that are not produced in radar observations. Similar features occur across several different bulk microphysics schemes, despite surface observations exhibiting cold pool equivalent potential temperature drops that are similar to and pressure rises that are greater than those in the simulation. Observed rear inflow remains more elevated than simulated, partly counteracting the cold pool circulation, whereas the simulated rear inflow descends to low levels, maintaining its strength and reinforcing the cold pool circulation that overpowers the pre-squall line low level vertical wind shear. The descent and strength of the simulated rear inflow is fueled by strong latent cooling caused by large ice water contents detrained from upshear tilted convective cores that accumulate at the rear of the stratiform region. This simulated squall evolution is sensitive to model resolution, which is too coarse to resolve individual convective drafts. Nesting a 250-m horizontal grid spacing domain into the 750-m domain substantially alters the initial convective cells with reduced latent cooling, weaker convective downdrafts, and a weaker initial cold pool. As the initial convective cells develop into a squall line, the rear inflow remains more elevated in the 250-m domain with a cold pool that eventually develops to be just as strong and deeper than the one in the 750-m run. Despite this, the convective cores remain more upright in the 250-m run with the rear inflow partly counteracting the cold pool circulation, whereas the 750-m rear inflow near the surface reinforces the shallower cold pool and causes bowing in the squall line. The different structure in the 750-m run produces excessive mid-level front-to-rear detrainment that widens the convective region relative to the 250-m run and observations while continuing the cycle of excessive latent cooling and rear inflow descent at the rear of the stratiform region in a positive feedback. The causes of initial convective structure differences that produce the divergence in simulated squall line evolutions are explored.

Ocean Data Assimilation in Support of Climate Applications: Status and Perspectives.

PubMed

Stammer, D; Balmaseda, M; Heimbach, P; Köhl, A; Weaver, A

2016-01-01

Ocean data assimilation brings together observations with known dynamics encapsulated in a circulation model to describe the time-varying ocean circulation. Its applications are manifold, ranging from marine and ecosystem forecasting to climate prediction and studies of the carbon cycle. Here, we address only climate applications, which range from improving our understanding of ocean circulation to estimating initial or boundary conditions and model parameters for ocean and climate forecasts. Because of differences in underlying methodologies, data assimilation products must be used judiciously and selected according to the specific purpose, as not all related inferences would be equally reliable. Further advances are expected from improved models and methods for estimating and representing error information in data assimilation systems. Ultimately, data assimilation into coupled climate system components is needed to support ocean and climate services. However, maintaining the infrastructure and expertise for sustained data assimilation remains challenging.

The evolution of misoscale circulations in a downburst-producing storm and comparison to numerical results

NASA Technical Reports Server (NTRS)

Kessinger, C. J.; Wilson, J. W.; Weisman, M.; Klemp, J.

1984-01-01

Data from three NCAR radars are used in both single and dual Doppler analyses to trace the evolution of a June 30, 1982 Colorado convective storm containing downburst-type winds and strong vortices 1-2 km in diameter. The analyses show that a series of small circulations formed along a persistent cyclonic shear boundary; at times as many as three misocyclones were present with vertical vorticity values as large as 0.1/s using a 0.25 km grid interval. The strength of the circulations suggests the possibility of accompanying tornadoes or funnels, although none were observed. Dual-Doppler analyses show that strong, small-scale downdrafts develop in close proximity to the misocyclones. A midlevel mesocyclone formed in the same general region of the storm where the misocylones later developed. The observations are compared with numerical simulations from a three-dimensional cloud model initialized with sounding data from the same day.

Seeding hydrate formation in water-saturated sand with dissolved-phase methane obtained from hydrate dissolution: A progress report

USGS Publications Warehouse

Waite, William F.; Osegovic, J.P.; Winters, William J.; Max, M.D.; Mason, David H.

2008-01-01

An isobaric flow loop added to the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) is being investigated as a means of rapidly forming methane hydrate in watersaturated sand from methane dissolved in water. Water circulates through a relatively warm source chamber, dissolving granular methane hydrate that was pre-made from seed ice, then enters a colder hydrate growth chamber where hydrate can precipitate in a water-saturated sand pack. Hydrate dissolution in the source chamber imparts a known methane concentration to the circulating water, and hydrate particles from the source chamber entrained in the circulating water can become nucleation sites to hasten the onset of hydrate formation in the growth chamber. Initial results suggest hydrate grows rapidly near the growth chamber inlet. Techniques for establishing homogeneous hydrate formation throughout the sand pack are being developed.

Cytomorphology of Circulating Colorectal Tumor Cells:A Small Case Series

PubMed Central

Marrinucci, Dena; Bethel, Kelly; Lazar, Daniel; Fisher, Jennifer; Huynh, Edward; Clark, Peter; Bruce, Richard; Nieva, Jorge; Kuhn, Peter

2010-01-01

Several methodologies exist to enumerate circulating tumor cells (CTCs) from the blood of cancer patients; however, most methodologies lack high-resolution imaging, and thus, little is known about the cytomorphologic features of these cells. In this study of metastatic colorectal cancer patients, we used immunofluorescent staining with fiber-optic array scanning technology to identify CTCs, with subsequent Wright-Giemsa and Papanicolau staining. The CTCs were compared to the corresponding primary and metastatic tumors. The colorectal CTCs showed marked intrapatient pleomorphism. In comparison to the corresponding tissue biopsies, cells from all sites showed similar pleomorphism, demonstrating that colorectal CTCs retain the pleomorphism present in regions of solid growth. They also often retain particular cytomorphologic features present in the patient's primary and/or metastatic tumor tissue. This study provides an initial analysis of the cytomorphologic features of circulating colon cancer cells, providing a foundation for further investigation into the significance and metastatic potential of CTCs. PMID:20111743

On the validation of a code and a turbulence model appropriate to circulation control airfoils

NASA Technical Reports Server (NTRS)

Viegas, J. R.; Rubesin, M. W.; Maccormack, R. W.

1988-01-01

A computer code for calculating flow about a circulation control airfoil within a wind tunnel test section has been developed. This code is being validated for eventual use as an aid to design such airfoils. The concept of code validation being used is explained. The initial stages of the process have been accomplished. The present code has been applied to a low-subsonic, 2-D flow about a circulation control airfoil for which extensive data exist. Two basic turbulence models and variants thereof have been successfully introduced into the algorithm, the Baldwin-Lomax algebraic and the Jones-Launder two-equation models of turbulence. The variants include adding a history of the jet development for the algebraic model and adding streamwise curvature effects for both models. Numerical difficulties and difficulties in the validation process are discussed. Turbulence model and code improvements to proceed with the validation process are also discussed.

β-Hydroxy-β-methylbutyrate (HMB)-free acid attenuates circulating TNF-α and TNFR1 expression postresistance exercise.

PubMed

Townsend, Jeremy R; Fragala, Maren S; Jajtner, Adam R; Gonzalez, Adam M; Wells, Adam J; Mangine, Gerald T; Robinson, Edward H; McCormack, William P; Beyer, Kyle S; Pruna, Gabriel J; Boone, Carleigh H; Scanlon, Tyler M; Bohner, Jonathan D; Stout, Jeffrey R; Hoffman, Jay R

2013-10-15

The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyrate-free acid (HMB-FA) and cold-water immersion (CWI) on circulating concentrations of TNF-α and monocyte TNF-α receptor 1 (TNFR1) expression. Forty resistance-trained men (22.3 ± 2.4 yr) were randomized into four groups [placebo (PL), HMB-FA, CWI, and HMB-FA-CWI] and performed an acute, intense exercise protocol (four sets of up to 10 repetitions of the squat, dead lift, and split squat). Participants also performed four sets of up to 10 repetitions of the squat at 24 and 48 h following the initial exercise bout. Blood was sampled before exercise (PRE), immediately postexercise (IP), and 30 min, 24 h, and 48 h postexercise (30P, 24P, and 48P, respectively). Circulating TNF-α was assayed, and TNFR1 expression on CD14+ monocytes was measured by flow cytometry. The exercise protocol significantly elevated TNF-α in only PL (P = 0.006) and CWI (P = 0.045) IP. Mean percent changes show that TNF-α significantly increased from PRE to IP for only PL and CWI groups (P < 0.05), whereas the percent change of TNF-α for HMB-FA and HMB-FA-CWI was not significant. TNFR1 expression was elevated in PL (P = 0.023) and CWI (P = 0.02) at 30P compared with PRE, whereas both HMB-FA-treated groups did not increase significantly. In conclusion, HMB-FA attenuated circulating TNF-α IP and TNFR1 expression during recovery compared with PL and CWI. HMB-FA supplementation may attenuate the initial immune response to intense exercise, which may reduce recovery time following intense exercise.

Deep water characteristics and circulation in the South China Sea

NASA Astrophysics Data System (ADS)

Wang, Aimei; Du, Yan; Peng, Shiqiu; Liu, Kexiu; Huang, Rui Xin

2018-04-01

This study investigates the deep circulation in the South China Sea (SCS) using oceanographic observations combined with results from a bottom layer reduced gravity model. The SCS water, 2000 m below the surface, is quite different from that in the adjacent Pacific Ocean, and it is characterized by its low dissolved oxygen (DO), high temperature and low salinity. The horizontal distribution of deep water properties indicates a basin-scale cyclonic circulation driven by the Luzon overflow. The results of the bottom layer reduced gravity model are consistent with the existence of the cyclonic circulation in the deep SCS. The circulation is stronger at the northern/western boundary. After overflowing the sill of the Luzon Strait, the deep water moves broadly southwestward, constrained by the 3500 m isobath. The broadening of the southward flow is induced by the downwelling velocity in the interior of the deep basin. The main deep circulation bifurcates into two branches after the Zhongsha Islands. The southward branch continues flowing along the 3500 m isobath, and the eastward branch forms the sub-basin scale cyclonic circulation around the seamounts in the central deep SCS. The returning flow along the east boundary is fairly weak. The numerical experiments of the bottom layer reduced gravity model reveal the important roles of topography, bottom friction, and the upwelling/downwelling pattern in controlling the spatial structure, particularly the strong, deep western boundary current.

Disinfection of Escherichia coli bacteria using hybrid method of ozonation and hydrodynamic cavitation with orifice plate

NASA Astrophysics Data System (ADS)

Karamah, Eva F.; Ghaudenson, Rioneli; Amalia, Fitri; Bismo, Setijo

2017-11-01

This research aims to evaluate the performance of hybrid method of ozonation and hydrodynamic cavitation with orifice plate on E.coli bacteria disinfection. In this research, ozone dose, circulation flowrate, and disinfection method were varied. Ozone was produced by commercial ozonator with ozone dose of 64.83 mg/hour, 108.18 mg/hour, and 135.04 mg/hour. Meanwhile, hydrodynamic cavitation was generated by an orifice plate. The disinfection method compared in this research were: hydrodynamic cavitation, ozonation, and the combination of both. The best result on each method was achieved on the 60th minutes and with a circulation flowrate of 7 L/min. The hybrid method attained final concentration of 0 CFU/mL from the initial concentration of 2.10 × 105 CFU/mL. The ozonation method attained final concentration of 0 CFU/mL from the initial concentration of 1.32 × 105 CFU/mL. Cavitation method gives the least disinfection with final concentration of 5.20 × 104 CFU/mL from the initial concentration of 2.17 × 105 CFU/mL. In conclusion, hybrid method gives a faster and better disinfection of E.coli than each method on its own.

Blood clearance and biodistribution of polymer brush-afforded silica particles prepared by surface-initiated living radical polymerization.

PubMed

Ohno, Kohji; Akashi, Tatsuki; Tsujii, Yoshinobu; Yamamoto, Masaya; Tabata, Yasuhiko

2012-03-12

The physiological properties of polymer brush-afforded silica particles prepared by surface-initiated living radical polymerization were investigated in terms of the circulation lifetime in the blood and distribution in tissues. Hydrophilic polymers consisting mainly of poly(poly(ethylene glycol) methyl ether methacrylate) were grafted onto silica particles by surface-initiated atom transfer radical polymerization that was mediated by a copper complex to produce hairy hybrid particles. A series of hybrid particles was synthesized by varying the diameter of the silica core and the chain length of the polymer brush to examine the relationship between their physicochemical and physiological properties. The hybrid particles were injected intravenously into mice to investigate systematically their blood clearance and body distribution. It was revealed that the structural features of the hybrid particles significantly affected their in vivo pharmacokinetics. Some hybrid particles exhibited an excellently prolonged circulation lifetime in the blood with a half life of ∼20 h. When such hybrid particles were injected intravenously into a tumor-bearing mouse, they preferentially accumulated in tumor tissue. The tumor-targeted delivery was optically visualized using hybrid particles grafted with fluorescence-labeled polymer brushes.

The Ocean Topography Experiment (TOPEX) - Some questions answered

NASA Technical Reports Server (NTRS)

Townsend, W. F.

1985-01-01

The Ocean Topography Experiment (TOPEX) is to provide a basis for improving the understanding of the general circulation of the global oceans. In the context of this experiment, measurements of the surface topography of the oceans are to be conducted with the aid of radar altimetry. The obtained data, when combined with appropriate in situ observations, will make it possible to determine the three-dimensional structure of the ocean currents. The in situ observations needed are to be provided by the World Ocean Circulation Experiment (WOCE). Information regarding the ocean surface winds obtained with the aid of the NASA Scatterometer (NSCAT) to be flown on the Navy Remote Ocean Sensing System (N-ROSS) can supplement the TOPEX and WOCE data about the oceans. The TOPEX satellite is to be designed for a three year lifetime, but it will carry expendables for two additional years. Attention is given to TOPEX as an international program, aspects of timing regarding the conduction of the various experiments dealing with the oceans and the global climate, and the special characteristics of the TOPEX mission.

Sensitivity of the overturning circulation of the Baltic Sea to climate change, a numerical experiment

NASA Astrophysics Data System (ADS)

Hordoir, Robinson; Höglund, Anders; Pemberton, Per; Schimanke, Semjon

2018-02-01

An ocean model covering the Baltic Sea area is forced by several climate scenarios for a period extending from 1961 to 2100. The Baltic Sea overturning circulation is then analyzed. The analysis shows that this circulation decreases between the end of the 20th century and the end of the 21st century, and that the decrease is amplified in the case of the strongest greenhouse gas emission scenarios, which corresponds with the highest warming cases. The reasons behind this decrease in overturning circulation are investigated. A strong increase of thermal stratification is noticed at the level of the Baltic Sea mixed layer. Based on buoyancy flux considerations, we demonstrate that the decrease in overturning circulation coincides with the increase of thermal stratification. Evidence shows that the underlying process is linked to a smaller erosion of the halocline due to a higher shielding, itself linked with a stronger and longer seasonal thermocline. This theory works if surface wind mixing is not taken into account directly in the computation of buoyancy fluxes.

Response to perturbations for granular flow in a hopper

NASA Astrophysics Data System (ADS)

Wambaugh, John F.; Behringer, Robert P.; Matthews, John V.; Gremaud, Pierre A.

2007-11-01

We experimentally investigate the response to perturbations of circular symmetry for dense granular flow inside a three-dimensional right-conical hopper. These experiments consist of particle tracking velocimetry for the flow at the outer boundary of the hopper. We are able to test commonly used constitutive relations and observe granular flow phenomena that we can model numerically. Unperturbed conical hopper flow has been described as a radial velocity field with no azimuthal component. Guided by numerical models based upon continuum descriptions, we find experimental evidence for secondary, azimuthal circulation in response to perturbation of the symmetry with respect to gravity by tilting. For small perturbations we can discriminate between constitutive relations, based upon the agreement between the numerical predictions they produce and our experimental results. We find that the secondary circulation can be suppressed as wall friction is varied, also in agreement with numerical predictions. For large tilt angles we observe the abrupt onset of circulation for parameters where circulation was previously suppressed. Finally, we observe that for large tilt angles the fluctuations in velocity grow, independent of the onset of circulation.

Inter-annual variability of the Mediterranean thermohaline circulation in Med-CORDEX simulations

NASA Astrophysics Data System (ADS)

Vittoria Struglia, Maria; Adani, Mario; Carillo, Adriana; Pisacane, Giovanna; Sannino, Gianmaria; Beuvier, Jonathan; Lovato, Tomas; Sevault, Florence; Vervatis, Vassilios

2016-04-01

Recent atmospheric reanalysis products, such as ERA40 and ERA-interim, and their regional dynamical downscaling prompted the HyMeX/Med-CORDEX community to perform hind-cast simulations of the Mediterranean Sea, giving the opportunity to evaluate the response of different ocean models to a realistic inter-annual atmospheric forcing. Ocean numerical modeling studies have been steadily improving over the last decade through hind-cast processing, and are complementary to observations in studying the relative importance of the mechanisms playing a role in ocean variability, either external forcing or internal ocean variability. This work presents a review and an inter-comparison of the most recent hind-cast simulations of the Mediterranean Sea Circulation, produced in the framework of the Med-CORDEX initiative, at resolutions spanning from 1/8° to 1/16°. The richness of the simulations available for this study is exploited to address the effects of increasing resolution, both of models and forcing, the initialization procedure, and the prescription of the atmospheric boundary conditions, which are particularly relevant in order to model a realistic THC, in the perspective of fully coupled regional ocean-atmosphere models. The mean circulation is well reproduced by all the simulations. However, it can be observed that the horizontal resolution of both atmospheric forcing and ocean model plays a fundamental role in the reproduction of some specific features of both sub-basins and important differences can be observed among low and high resolution atmosphere forcing. We analyze the mean circulation on both the long-term and decadal time scale, and the represented inter-annual variability of intermediate and deep water mass formation processes in both the Eastern and Western sub-basins, finding that models agree with observations in correspondence of specific events, such as the 1992-1993 Eastern Mediterranean Transient, and the 2005-2006 event in the Gulf of Lion. Long-term trends of the hydrological properties have been investigated at sub-basin scale and have been interpreted in terms of response to forcing and boundary conditions, detectable differences resulting mainly due either to the different initialization and spin up procedure or to the different prescription of Atlantic boundary conditions.

Technology Transfer at Edgar Mine: Phase 1; October 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Augustine, Chad R.; Bauer, Stephen; Nakagawa, Masami

The objective of this project is to study the flow of fluid through the fractures and to characterize the efficiency of heat extraction (heat transfer) from the test rock mass in the Edgar Mine, managed by Colorado School of Mines in Idaho Springs, CO. The experiment consists of drilling into the wall of the mine and fracturing the rock, characterizing the size and nature of the fracture network, circulating fluid through the network, and measuring the efficiency of heat extraction from the 'reservoir' by monitoring the temperature of the 'produced' fluid with time. This is a multi-year project performed asmore » a collaboration between the National Renewable Energy Laboratory, Colorado School of Mines and Sandia National Laboratories and carried out in phases. This report summarizes Phase 1: Selection and characterization of the location for the experiment, and outlines the steps for Phase 2: Circulation Experiments.« less

The general circulation in the eastern Algerian subbasin inferred from the ELISA experiment

NASA Astrophysics Data System (ADS)

Aubertin, E.; Millot, C.; Taupier-Letage, I.; Albérola, C.; Robin, S.; Font, J.

2003-04-01

About 40 current meters were set at nominal depths of 100, 350, 1000, 1800 and 2700 m on 9 moorings in the eastern Algerian subbasin from July 1997 to July 1998 during the ELISA operation (http://www.com.univ-mrs.fr/ELISA/). Most moorings were located on the 2800-m isobath, and all data sets were checked using the tidal currents analysis (Albérola et al., 1995). They allow i) confirming known features about the alongslope circulation, ii) proving that Algerian Eddies (AE's) can extend down to the bottom and iii) evidencing an anticlockwise circulation at intermediate and greater depths in the whole subbasin. i) At about 50 km from the Algerian and Sardinian coastlines, the general circulation is clearly alongslope and anticlockwise at all depths, as during previous experiments (Millot, 1994; Bouzinac et al., 1999). It is also confirmed that alongslope currents are generally larger closer to the bottom than at intermediate depths, with most annual means from 350 to 2700 m in the range 3-6 cm/s, up to about 10 cm/s at 2700 m on one mooring. This permanent (unless disturbed by AE's, see ii)) and extremely large circulation is still not well simulated by the general circulation models, which still prevents from getting a correct understanding of the functioning of the whole western basin. ii) During the experiment, three 100-200 km AE's (96-1, 97-1, and 98-2) have been identified following the anticlockwise circuit that was first specified by Fuda et al. (2000) in the study area. One of them (96-1), which had a lifetime of about 3 years (Puillat et al., 2002), remained stationary during about 5 months and was well sampled at that time by 3 moorings at least. This AE, as all AE's previously sampled (Millot et al., 1997; Ruiz et al., 2002), was clearly an anticyclone, not only in the surface AW layer, but also in the whole deep layer (i.e. down to 2800 m). Alongslope, the eddy-associated current is opposed to the general circulation at all depths, and can even be larger. When it started propagating again, 96-1 still extended over the whole depth at least during a couple of months, before markedly reducing its signature. Contrary to what is said by Testor (2002), the lagrangian floats that were launched at about 600 m within 96-1 at the beginning of the experiment did confirm the anticyclonic rotation in the intermediate layer at least (data provided by J.C. Gascard and P. Testor). These observations are seemingly consistent with many other float trajectories at 1200 and 1950 m (U. Send, personal communication) that clearly evidence mesoscale anticyclonic loops. The ELISA time series, as well as the MEDIPROD-5 ones (Millot et al., 1997) clearly confirm that the current associated with an AE has the same amplitude and phase within the whole deep layer. This is consistent with laboratory experiments and with the (sole?) hypothesis of Obaton et al. (2000) that the deep circulation within an AE is forced by a pressure effect from the surface layer. However, theoretical analyses and numerical models are, to our knowledge, not available yet to confirm this hypothesis and / or explain the actual processes yet. iii) Moorings located in the middle of the eastern Algerian subbasin, as well as the float trajectories mentioned above in the whole subbasin (south of about 39 °N), do account for an overall anticlockwise circulation in the whole deep layer. This circulation roughly corresponds to the circuit of the AE's described above. It must be noticed that most of this closed circulation is embedded in the overall alongslope circulation (from Algeria to Sardinia), thus being associated with relatively large speeds increasing with depth (as described above). Closure of this circuit (roughly from Sardinia to Balearic Islands and Algeria) do reveal very different characteristics with annual means lower than 3 cm/s decreasing with depth. Reasons for such a well defined, although not permanent, closed circulation in the eastern Algerian subbasin, and relationships with both the bathymetry and the AE's dynamics are under study Albérola C., S. Rousseau, C. Millot, M. Astraldi, J. Font, J. Garcia-Lafuente, G.P. Gasparini, U. Send and A. Vangriesheim, 1995. Tidal currents in the interior of the Western Mediterranean Sea. Oceanol. Acta, 18, 2, 273-284. Bouzinac C., J. Font and C. Millot, 1999. Hydrology and currents observed in the channel of Sardinia during the PRIMO-1 experiment from November 1993 to October 1994. J. Mar. Systems, 20, 1-4, 333-355. Fuda J.-L., C. Millot, I. Taupier-Letage, U. Send and J.M. Bocognano, 2000. XBT monitoring of a meridian section across the Western Mediterranean Sea. Deep-Sea Res., I 47, 2191-2218. Millot C., 1994. Models and data: a synergetic approach in the western Mediterranean Sea. Erice School Proceedings,"Ocean Processes in Climate Dynamics: Global and Mediterranean Examples", P. Malanotte-Rizzoli and A.R. Robinson eds, 407-425. Millot C., I. Taupier-Letage and M. Benzohra, 1997. Circulation off Algeria inferred from the Médiprod-5 current meters. Deep-Sea Res., 44, 9-10, 1467-1495. Obaton D., C. Millot, G. Chabert D'Hières and I. Taupier-Letage, 2000. The Algerian Current: comparisons between in situ and laboratory measurements. Deep-Sea Res., I 47, 2159-2190. Puillat I., I.Taupier-Letage and C. Millot. Algerian eddies lifetimes can near 3 years, 2002. Journal of Marine Syst., 31, 4, 245-259. Ruiz S., J. Font, M.Emelianov, J. Isern-Fontanet, C. Millot and I. Taupier-Letage, 2002. Deep structure of an open sea eddy in the Algerian Basin. J. Mar. Sys., 33-34, 179-195. Testor P., 2002. Etude lagrangienne de circulations tourbillonnaires de subméso et méso échelle en Méditerranée occidentale sur la base d'observations et de simulations numériques : phénoménologie et interaction avec la circulation générale. Thèse de Doctorat d'Université, Paris 6.

The Aqua-planet Experiment (APE): Response to Changed Meridional SST Profile

NASA Technical Reports Server (NTRS)

Williamson, David L.; Blackburn, Michael; Nakajima, Kensuke; Ohfuchi, Wataru; Takahashi, Yoshiyuki O.; Hayashi, Yoshi-Yuki; Nakamura, Hisashi; Ishiwatari, Masaki; Mcgregor, John L.; Borth, Hartmut;

Buoyancy forcing and the MOC: insights from experiments, simulations and global models

NASA Astrophysics Data System (ADS)

White, B. L.; Passaggia, P. Y.; Zemskova, V.

2017-12-01

The driving forces behind the Meridional Overturning Circulation (MOC) have been widely debated, with wind-driven upwelling, surface buoyancy fluxes due to heating/cooling/freshwater input, and vertical diffusion due to turbulent mixing all thought to play significant roles. To explore the specific role of buoyancy forcing we present results from experiments and simulations of Horizontal Convection (HC), where a circulation is driven by differential buoyancy forcing applied along a horizontal surface. We interpret these results using energy budgets based on the local Available Potential Energy framework introduced in [Scotti and White, J. Fluid Mech., 2014]. We first describe HC experiments driven by the diffusion of salt in water across membranes localized at the surface, at Schmidt numbers {Sc}≈ 610 and Rayleigh numbers in the range 1012 < Ra=Δ b L3/(ν κ ) < 1017, where ν is the kinematic viscosity of water, κ is the diffusion coefficient of salt, L=[.5,2,5]m is the length of the different tanks and Δ b=g(ρ salt}-ρ {fresh}/ρ_{fresh is the reduced gravity difference. We show that the scaling follows a Nu ˜ Ra1/4 type scaling recently theorized by Shishkina et; al. (2016). We then present numerical results for rotating horizontal convection with a zonally re-entrant channel to represent the Southern Ocean branch of the MOC. While the zonal wind stress profile is important to the spatial pattern of the circulation, perhaps surprisingly, the energy budget shows only a weak dependence on the magnitude of the wind input, suggesting that surface APE generation by buoyancy forcing is dominant in driving the overturning circulation.

Numerical Study of Interaction of a Vortical Density Inhomogeneity with Shock and Expansion Waves

NASA Technical Reports Server (NTRS)

Povitsky, A.; Ofengeim, D.

1998-01-01

We studied the interaction of a vortical density inhomogeneity (VDI) with shock and expansion waves. We call the VDI the region of concentrated vorticity (vortex) with a density different from that of ambiance. Non-parallel directions of the density gradient normal to the VDI surface and the pressure gradient across a shock wave results in an additional vorticity. The roll-up of the initial round VDI towards a non-symmetrical shape is studied numerically. Numerical modeling of this interaction is performed by a 2-D Euler code. The use of an adaptive unstructured numerical grid makes it possible to obtain high accuracy and capture regions of induced vorticity with a moderate overall number of mesh points. For the validation of the code, the computational results are compared with available experimental results and good agreement is obtained. The interaction of the VDI with a propagating shock wave is studied for a range of initial and induced circulations and obtained flow patterns are presented. The splitting of the VDI develops into the formation of a non-symmetrical vortex pair and not in a set of vortices. A method for the analytical computation of an overall induced circulation Gamma(sub 1) as a result of the interaction of a moving VDI with a number of waves is proposed. Simplified, approximated, expressions for Gamma(sub 1) are derived and their accuracy is discussed. The splitting of the VDI passing through the Prandtl-Meyer expansion wave is studied numerically. The obtained VDI patterns are compared to those for the interaction of the VDI with a propagating shock wave for the same values of initial and induced circulations. These patterns have similar shapes for corresponding time moments.

Fever of unknown origin in the elderly.

PubMed

Wakefield, K M; Henderson, S T; Streit, J G

1989-06-01

Fever is a prominent sign of an acute-phase response induced by microbial invasion, tissue injury, immunologic reactions, or inflammatory processes. This generalized host response is produced by a multiplicity of localized or systemic diseases and characterized by acute, subacute, or chronic changes in metabolic, endocrinologic, neurologic, and immunologic functions. The fundamental event is an initiation of the acute-phase response by the production of a mediated molecule called IL-1. This polypeptide is produced primarily from phagocytic cells such as blood monocytes, phagocytic lining cells of the liver and spleen, and other tissue macrophages. IL-1 produces a local reaction but also enters the circulation, acting as a hormone to mediate distant organ system responses to infection, immunologic reaction, and inflammatory processes. Fever is the result when IL-1 initiates the synthesis of prostaglandins, notably prostaglandin E2 in the thermoregulatory center located in the anterior hypothalamus. The thermostatic set point is then raised and mechanisms to conserve heat (vasoconstriction) and to produce heat (shivering) are initiated. The result is a sudden rise in body temperature. The same basic mechanisms are involved in FUO. Many of the biologic and biochemical changes that are seen in FUO are also evidence of an acute-phase response. The elevated erythrocyte sedimentation rate is partly due to increased synthesis of hepatic proteins, including compliment components, ceruloplasmin, fibrinogen, and C-reactive protein. IL-1 acts directly on the bone marrow to increase absolute numbers and immaturity of circulating neutrophils. Anemia is produced by many mechanisms, including the reduction of circulating serum iron. Although fever production in the elderly maybe delayed or of less intensity, it is still a marker of significant disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Cloud, Aerosol, and Complex Terrain Interactions (CACTI) Preliminary Science Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varble, Adam; Nesbitt, Steve; Salio, Paola

General circulation models and downscaled regional models exhibit persistent biases in deep convective initiation location and timing, cloud top height, stratiform area and precipitation fraction, and anvil coverage. Despite important impacts on the distribution of atmospheric heating, moistening, and momentum, nearly all climate models fail to represent convective organization, while system evolution is not represented at all. Improving representation of convective systems in models requires characterization of their predictability as a function of environmental conditions, and this characterization depends on observing many cases of convective initiation, non-initiation, organization, and non-organization. The Cloud, Aerosol, and Complex Terrain Interactions (CACTI) experiment inmore » the Sierras de Córdoba mountain range of north-central Argentina is designed to improve understanding of cloud life cycle and organization in relation to environmental conditions so that cumulus, microphysics, and aerosol parameterizations in multi-scale models can be improved. The Sierras de Córdoba range has a high frequency of orographic boundary-layer clouds, many reaching congestus depths, many initiating into deep convection, and some organizing into mesoscale systems uniquely observable from a single fixed site. Some systems even grow upscale to become among the deepest, largest, and longest-lived in the world. These systems likely contribute to an observed regional trend of increasing extreme rainfall, and poor prediction of them likely contributes to a warm, dry bias in climate models downstream of the Sierras de Córdoba range in a key agricultural region. Many environmental factors influence the convective lifecycle in this region including orographic, low-level jet, and frontal circulations, surface fluxes, synoptic vertical motions influenced by the Andes, cloud detrainment, and aerosol properties. Local and long-range transport of smoke resulting from biomass burning as well as blowing dust are common in the austral spring, while changes in land surface properties as the wet season progresses impact surface fluxes and boundary layer evolution on daily and seasonal time scales that feed back to cloud and rainfall generation. This range of environmental conditions and cloud properties coupled with a high frequency of events makes this an ideal location for improving our understanding of cloud-environment interactions. The following primary science questions will be addressed through coordinated first ARM Mobile Facility (AMF1), mobile C-band Scanning ARM Precipitation Radar (C-SAPR2), guest instrumentation, and potential ARM Aerial Facility (AAF) Gulfstream-1 (G-1) observations: 1. How are the properties and lifecycles of orographically generated cumulus humulis, mediocris, and congestus clouds affected by environmental kinematics, thermodynamics, aerosols, and surface properties? How do these cloud types alter these environmental conditions? 2. How do environmental kinematics, thermodynamics, and aerosols impact deep convective initiation, upscale growth, and mesoscale organization? How are soil moisture, surface fluxes, and aerosol properties altered by deep convective precipitation events and seasonal accumulation of precipitation? This multi-faceted experiment involves a long term 8.5-month Extended Observing Period (EOP, 15 August, 2018-30 April, 2019) as well as a 6-week Intensive Observation Period (IOP, 1 November-15 December) that will coincide with the international multi-agency RELAMPAGO field campaign.« less

On the Origin of Monsoon

NASA Technical Reports Server (NTRS)

Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

2000-01-01

It is a long-held fundamental belief that the basic cause of a monsoon is land-sea thermal contrast on the continental scale. Through general circulation model experiments we demonstrate that this belief should be changed. The Asian and Australian summer monsoon circulations are largely intact in an experiment in which Asia, maritime continent, and Australia are replaced by ocean. It is also shown that the change resulting from such replacement is in general due more to the removal of topography than to the removal of land-sea contrast. Therefore, land-sea contrast plays only a minor modifying role in Asian and Australian summer monsoons. This also happens to the Central American summer monsoon. However, the same thing cannot be said of the African and South American summer monsoons. In Asian and Australian winter monsoons land-sea contrast also plays only a minor role. Our interpretation for the origin of monsoon is that the summer monsoon is the result of ITCZ's (intertropical convergence zones) peak being substantially (more than 10 degrees) away from the equator. The origin of the ITCZ has been previously interpreted by Chao. The circulation around thus located ITCZ, previously interpreted by Chao and Chen through the modified Gill solution and briefly described in this paper, explains the monsoon circulation. The longitudinal location of the ITCZs is determined by the distribution of surface conditions. ITCZ's favor locations of higher SST as in western Pacific and Indian Ocean, or tropical landmass, due to land-sea contrast, as in tropical Africa and South America. Thus, the role of landmass in the origin of monsoon can be replaced by ocean of sufficiently high SST. Furthermore, the ITCZ circulation extends into the tropics in the other hemisphere to give rise to the winter monsoon circulation there. Also through the equivalence of land-sea contrast and higher SST, it is argued that the basic monsoon onset mechanism proposed by Chao is valid for all monsoons.

PROTEIN METABOLISM AND EXCHANGE AS INFLUENCED BY CONSTRICTION OF THE VENA CAVA

PubMed Central

McKee, Frank W.; Hyatt, Robert E.; Wilt, William G.; Tishkoff, Garson H.; Whipple, George H.

1949-01-01

Further studies of ascitic fluid production and related factors in dogs with constriction of the vena cava above the diaphragm are reported. Whole dog plasma given intravenously to such animals produces a rise in circulating plasma protein to normal levels, but increases the output of ascitic fluid with a loss of protein via the ascites equivalent to 72, 76, and 65 per cent respectively, of the injected protein. Forced ingestion of water in excess of the test animal's normal needs and desires produces no significant changes in the circulating plasma protein level or in ascitic fluid production. Amino acid growth mixtures given intravenously in distilled water cause weight loss, elevation of circulating plasma proteins, a slightly negative nitrogen balance, but no ascitic fluid production. Amino acid growth mixtures given intravenously in normal saline cause depression of the circulating plasma proteins, negative nitrogen balance, and significant ascitic fluid production. Ascitic fluid given intravenously to the test animals causes a marked depression of circulating plasma proteins, a marked increase in ascitic fluid production containing the equivalent of 116 and 98 per cent of the injected protein, and a negative nitrogen balance. Ascitic fluid given orally produces a marked depression of circulating plasma proteins, and a marked increase in ascitic fluid secretion, containing the equivalent of 66, 66, and 54 per cent respectively, of the ingested protein. Sodium chloride is a dominant factor in some of these experiments where abundant ascites production is recorded. Protein levels and intake are important, but take second place to sodium. Ascitic fluids show electrophoretic patterns which are almost identical to the plasma patterns. The A/G ratios are often equal in ascitic fluid and plasma, sometimes even lower in the ascitic fluid. This emphasizes the ease with which globulins pass cell or other membrane barriers in these experiments. PMID:18143588

The ECCO Family of State Estimates: An Overview

NASA Astrophysics Data System (ADS)

Wunsch, C.

2008-12-01

The idea of ECCO (Estimating the Circulation and Climate of the Ocean)originated in the middle 1980s, when it became apparent that a global oceanographic observing system for the general circulation would become a reality as it did through the World Ocean Circulation Experiment. Observational design involved extremely diverse technologies and oceanic flow regimes. To be physically interpretable, these diverse data and physical processes would need to be combined into a useful, coherent, whole. Such a synthesis can only be done with a skillful GCM having useful resolution. ECCO originated as an experiment to demonstrate the technical feasibility of such a synthesis and to determine if any of several possible methods was preferable. In contrast to a number of other superficially similar efforts, mainly derived from weather forecasting methods, the ECCO goal was to estimate the long-term circulation mean and its variability on climate (decadal and longer) time scales in a form exactly satisfying known equations of motion. ECCO was made feasible with the simultaneous construction of a new GCM (MIT) along with the development of an automatic differentiation (AD) software tool(now called TAF) which rendered practical the method of Lagrange multipliers (called the adjoint method in oceanography). Parallel developments of simplified sequential methods (smoothers) provided an alternative, also practical, methodology. One can now use the existing (publicly available) machinery to discuss the ocean circulation and its variability. The huge variety of issues connected with the global circulation has meant that an entire family of estimates has grown up, each having different emphases (primarily global; but some primarily regional---the tropics, the Southern Ocean); some focussed on physics---the role of eddies or sea ice). The methodology leads, usefully, to intense scrutiny of data and model errors and spatio-temporal coverage. As with any estimation problem, no uniquely 'correct' solution is now or ever going to be possible-- -only evolving best estimates. Further development of these and similar methodologies appears to be a necessary, inevitable, and growing component of oceanography and climate.

Multiscale and multidisciplinary Marine Rapid Environmental Assessment data collection methods for process studies: the case of the Taranto Gulf

NASA Astrophysics Data System (ADS)

Federico, Ivan; Maicu, Francesco; Pinardi, Nadia; Lyubartsev, Vladyslav; Causio, Salvatore; Caporale, Claudio; Demarte, Maurizio; Falconieri, Alfredo; Lecci, Rita; Lacava, Teodosio; Lisi, Matteo; Sepp-Neves, Augusto; Lorenzetti, Giuliano; Manfe', Giorgia; Trotta, Francesco; Zaggia, Luca; Ciliberti, Stefania Angela; Fratianni, Claudia; Grandi, Alessandro

2017-04-01

The present work aims to investigate the thermohaline properties and the circulation of the Gulf of Taranto, which is a deep, semi-enclosed ocean area in the northern Ionian sea, encircled by two Italian peninsulas of southern Apulia and Calabria. Since few observations in the past have been reported in the Gulf of Taranto, it emerged the need of planning and implementing oceanographic cruises in this area, based on an innovative concept of MREA (Marine Rapid Environmental Assessment). The methodology was based on an optimal experimental strategy to collect definitive evidences on ocean mesoscales with a spatial-and-time synoptic coverage. The MREA surveys have been performed thanks to the synergies between Italian oceanographic research centers and the Italian Navy Hydrographic Institute. Starting from the experience and results of MREA14 (Pinardi et al., 2016), which have shown in the Gulf an anticyclonic circulation in Autumn (October 2014) and the presence of submesoscale structure, a new experiment (MREA16) was repeated in a different season (Summer, June-July 2016), evaluating possible changes in current circulation. Furthermore, the new sampling methodology was refined and strengthened integrating the classical CTD data collection with additional simultaneous measurements of currents by means of vessel-mounted ADCP. The geostrophic circulation pattern derived from the CTD objective-analysis mapping techniques has been verified with the ADCP measurements. Moreover, the analysis on circulation fields confirms the presence of possible submesoscale structures, which can be well solved by a high-resolution sampling scheme. The MREA investigation in Gulf of Taranto shows a large-scale gyre anticyclonically-oriented in Autumn (MREA14) and cyclonically-oriented in Summer (MREA16). This opposite circulation pattern is probably connected to (i) the impact of Western Adriatic Coastal Current (WACC), (ii) the effect of the Northern Ionian Sea outflow-inflow system in different seasons and (iii) the local atmospheric forcing.

Evaluation of Global Ocean Data Assimilation Experiment Products on South Florida Nested Simulations with the Hybrid Coordinate Ocean Model

DTIC Science & Technology

2009-01-01

Ocean Model 7:285-322 Halliwell GR Jr, Weisberg RH, Mayer DA (2003) A synthetic float analysis of upper-limb meridional overturning circulation ...encompasses a variety of coastal regions (the broad Southwest Florida shelf, the narrow Atlantic Keys shelf, the shallow Florida Bay, and Biscayne...products. The results indicate that the successful hindcasting of circulation patterns in a coastal area that is characterized by complex topography and

Targeting CD81 to Prevent Metastases in Breast Cancer

DTIC Science & Technology

2015-10-01

in tumor cells would curb the formation of CTCs. Briefly, 4T1 cells either WT or cells in which CD81 has been knocked down stably using CRISPR -Cas9...expression in breast cancer cells impairs the number of circulating tumor cells . The experiments were performed using a protocol that we standardized for...detection of circulating tumor cells in an immunocompetent syngeneic mouse model of breast cancer using FASTcell™ system. 15. SUBJECT TERMS Breast

The Sterilization Effect of Cooperative Treatment of High Voltage Electrostatic Field and Variable Frequency Pulsed Electromagnetic Field on Heterotrophic Bacteria in Circulating Cooling Water

NASA Astrophysics Data System (ADS)

Gao, Xuetong; Liu, Zhian; Zhao, Judong

2018-01-01

Compared to other treatment of industrial circulating cooling water in the field of industrial water treatment, high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization technology, an advanced technology, is widely used because of its special characteristics--low energy consumption, nonpoisonous and environmentally friendly. In order to get a better cooling water sterilization effect under the premise of not polluting the environment, some experiments about sterilization of heterotrophic bacteria in industrial circulating cooling water by cooperative treatment of high voltage electrostatic field and variable frequency pulsed electromagnetic field were carried out. The comparison experiment on the sterilization effect of high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization on heterotrophic bacteria in industrial circulating cooling water was carried out by change electric field strength and pulse frequency. The results show that the bactericidal rate is selective to the frequency and output voltage, and the heterotrophic bacterium can only kill under the condition of sweep frequency range and output voltage. When the voltage of the high voltage power supply is 4000V, the pulse frequency is 1000Hz and the water temperature is 30°C, the sterilization rate is 48.7%, the sterilization rate is over 90%. Results of this study have important guiding significance for future application of magnetic field sterilization.

Greenland meltwater experiments

NASA Astrophysics Data System (ADS)

Olsen, S. M.; Schmith, T.

2012-04-01

We explore the climatic response to additional Greenland Ice Sheet melting in the EC-EARTH coupled climate model. As reference runs, we use an ensemble of two simulations from 1850 to present with historic forcing. For each of these we pick the years 1935,1950 and 1965, respectively as initial conditions for perturbed experiments with an additional freshwater forcing of 0.1 Sv distributed uniformly around Greenland , a plausible value in the upper end of future Greenland ice sheet melt estimates. We find give no evidence for abrupt transitions associated with tipping points in the Atlantic overturning circulation and mid-latitude heat transport. In fact, modelled decline in overturning in response to the additional forcing does not project onto a comparable reduction in the mid latitude (36N) ocean heat transport. This result points to an ongoing watermass transformation in the subpolar region and Arctic Mediterranean as a whole and a continued thermal mode of operation of the overturning. At the northern boundary of the subpolar region (60N) the response in overturning shows a contrasting increase in intensity along with an increase in heat transport. Whereas the latter may be expected as a result of freshwater capping and subsurface warming in the subpolar region, the increased overturning at 60N is more difficult to explain. In order to assess this in more detail we have quantified the individual thermohaline exchange components of light and dense water masses across the Greenland-Scotland Ridge. We find that the intensified overturning at 60N is reflected in increased transports of light Atlantic Water to the Nordic Seas. However, the vertical, thermohalinie overturning loop is not equally strengthened. On the contrary, we model a decline in the denser parts of the outflow, the overflows in the Denmark Strait and Faroe Bank Channel and a strong increase in the polar outflow in the Denmark Strait. We observe a gradual transition from a vertical mode of operation with 70% of the Atlantic Inflow being transformed to dense overflow towards a state approaching an equal contribution of the vertical and horizontal thermohaline circulation loops after 20-30 years. Along with this transition we find an overall decline in the intensity of the barotropic gyre circulation of the Nordic Seas reflecting in part a reduced winter deepening of the mixed layer. Thus, we may seek to explain this transition as a result of more efficient lateral mixing of the Atlantic Inflow during its cyclonic circulation around the basin margins. Finally, we show that the associated atmospheric response is a standing Rossby wave train reflected in the mean tropospheric thickness anomaly field with a through over Labrador Sea, a ridge over Barents Sea and a minor through over eastern Europe. Corresponding anomalies are found in the surface temperature field.

Quantification of Operational Learning in Minimal Invasive Extracorporeal Circulation.

PubMed

Anastasiadis, Kyriakos; Antonitsis, Polychronis; Asteriou, Christos; Argiriadou, Helena; Deliopoulos, Apostolos; Konstantinou, Dimitrios; Grosomanidis, Vassilios; Tossios, Paschalis

2017-07-01

Minimal invasive extracorporeal circulation (MiECC) has initiated important new efforts within science and technology towards a more physiologic perfusion. In this study, we aim to investigate the learning curve of our center regarding MiECC. We studied a series of 150 consecutive patients who underwent elective coronary artery bypass grafting by the same surgical team during the initial phase of MiECC application. Patients were randomly assigned into two groups. Group A (n = 75) included patients operated on MiECC, while group B (n = 75) included patients operated with conventional cardiopulmonary bypass (cCPB). The primary end-point of the study was to identify whether there is a learning curve when operating on MiECC. The following parameters were unrelated with increasing experience, even though the results favored MiECC use: reduced CPB duration (102.9 ± 25 vs. 122.2 ± 33 min, P <0.001), peak troponin release (0.07 ± 0.02 vs. 0.1 ± 0.04 ng/mL, P < 0.01), peak creatinine levels (0.97 ± 0.24 vs. 1.2 ± 0.3 mg/dL, P < 0.001), duration of mechanical ventilation (14.1 ± 7.2 vs. 36.9 ± 59.8 h, P < 0.01) and ICU stay (2.1 ± 0.7 vs. 4.4 ± 6.4 days, P < 0.01). However, need for intraoperative blood transfusion showed a trend towards a gradual decrease as experience with MiECC system was accumulating (R 2  = 0.094, P = 0.007). Subsequently, operational learning applied to postoperative hematocrit and hemoglobin levels (R 2  = 0.098, P = 0.006). We identified that advantages of MiECC technology in terms of reduced hemodilution and improved end-organ protection and clinical outcome are evident from the first patient. Optimal results are obtained with 50 cases; this refers mainly to significant reduction in the need for intraoperative blood transfusion. Teamwork from surgeons, anesthesiologists, and perfusionists is of paramount importance in order to maximize the clinical benefits from this technology. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

An Oceanic General Circulation Model (OGCM) investigation of the Red Sea circulation: 2. Three-dimensional circulation in the Red Sea

NASA Astrophysics Data System (ADS)

Sofianos, Sarantis S.; Johns, William E.

2003-03-01

The three-dimensional circulation of the Red Sea is studied using a set of Miami Isopycnic Coordinate Ocean Model (MICOM) simulations. The model performance is tested against the few available observations in the basin and shows generally good agreement with the main observed features of the circulation. The main findings of this analysis include an intensification of the along-axis flow toward the coasts, with a transition from western intensified boundary flow in the south to eastern intensified flow in the north, and a series of strong seasonal or permanent eddy-like features. Model experiments conducted with different forcing fields (wind-stress forcing only, surface buoyancy forcing only, or both forcings combined) showed that the circulation produced by the buoyancy forcing is stronger overall and dominates the wind-driven part of the circulation. The main circulation pattern is related to the seasonal buoyancy flux (mostly due to the evaporation), which causes the density to increase northward in the basin and produces a northward surface pressure gradient associated with the downward sloping of the sea surface. The response of the eastern boundary to the associated mean cross-basin geostrophic current depends on the stratification and β-effect. In the northern part of the basin this results in an eastward intensification of the northward surface flow associated with the presence of Kelvin waves while in the south the traditional westward intensification due to Rossby waves takes place. The most prominent gyre circulation pattern occurs in the north where a permanent cyclonic gyre is present that is involved in the formation of Red Sea Outflow Water (RSOW). Beneath the surface boundary currents are similarly intensified southward undercurrents that carry the RSOW to the sill to flow out of the basin into the Indian Ocean.

In vivo effect of staphylococcal enterotoxin A on peripheral blood lymphocytes.

PubMed Central

Zehavi-Willner, T; Shenberg, E; Barnea, A

1984-01-01

Staphylococcal enterotoxin A (SEA) administration to monkeys produced an initial lymphocytic leukopenia lasting approximately 24 h. Lymphocytes isolated from blood circulation (PBL) during this stage had normal or decreased [3H]thymidine incorporating activity. After 48 h, however, a significant increase (five- to sixfold) in [3H]thymidine incorporating activity into PBL was apparent. The peak of incorporating activity (seven- to eightfold) was reached 3 to 4 days after SEA administration, followed by a gradual decline, reaching the baseline after 2 weeks. The increased levels of [3H] thymidine incorporation in PBL were concomitant with the conversion of lymphopenia into lymphocytosis, accompanied by the release of many immature cells into the circulation. Lymphocytes isolated 24 h after SEA administration in vivo did not respond to the mitogenic action of SEA in vitro. Lymphocytes isolated at later stages after SEA challenge were fully activated by toxin. From a series of studies, it was concluded that SEA administered to monkeys caused, during the initial 24 h, the removal of a great proportion of lymphocytes from the circulation, followed by the release of new immature cells with augmented DNA synthesis activity. The lymphocytic leukocytosis state declined gradually and reached normal levels between 3 and 4 weeks after the SEA challenge. The biological implications of the hematological changes occurring after SEA challenge in vivo are discussed. PMID:6715041

New Version of Pimentel Report Is Learning Resource for Young People.

ERIC Educational Resources Information Center

Zurer, Pamela

1987-01-01

Reviews National Research Council's (NRC) book, "Opportunities in Chemistry: Today and Tomorrow." Describes the difference between this volume and the NRC's earlier version, "Opportunities in Chemistry." Discusses the initial circulation of the new volume. Indicates how to obtain the new volume. (CW)

The Future of Library Automation in Schools.

ERIC Educational Resources Information Center

Anderson, Elaine

2000-01-01

Addresses the future of library automation programs for schools. Discusses requirements of emerging OPACs and circulation systems; the Schools Interoperability Framework (SIF), an industry initiatives to develop an open specification for ensuring that K-12 instructional and administrative software applications work together more effectively; home…

Interannual to decadal variability of circulation in the northern Japan/East Sea, 1958-2006

NASA Astrophysics Data System (ADS)

Stepanov, Dmitry; Stepanova, Victoriia; Gusev, Anatoly

2015-04-01

We use a numerical ocean model INMOM (Institute of Numerical Mathematics Ocean Model) and atmospheric forcing data extracted from the CORE (Coordinated Ocean Reference Experiments) dataset and reconstruct a circulation in the Japan/East Sea (JES) from 1958 to 2006 and its interannual and decadal variability in the intermediate and abyssal layers in the northern JES. It is founded that the circulation is cyclonic over the course of a climatological year. The circulation increases in spring and decreases in autumn. We analyzes the relative vorticity (RV) averaged over the Japan Basin (JB) and show that the variability is characterized by the interannual oscillations (2.3, 3.7 and 4.7 years) and decadal variability (9.5 and 14.3 years). The spectrum structure of the average RV variability does not change with depth; however, the energy of the decadal oscillations decreases in contrast to that of the interannual oscillations. We analyze monthly anomalies of the wind stress curl and sensible heat flux and reveal that interannual variability (3-4 years) of the circulation over the JB result from 4-year variability of the wind stress curl. In contrast, the decadal variability (period of 9.5 years) of the circulation over the JB is generated by both the wind stress curl and the decadal variability in deep convection.

Simulation of mesoscale circulation in the Tatar Strait of the Japan Sea

NASA Astrophysics Data System (ADS)

Ponomarev, V. I.; Fayman, P. A.; Prants, S. V.; Budyansky, M. V.; Uleysky, M. Yu.

2018-06-01

The eddy-resolved ocean circulation model RIAMOM (Lee et al., 2003) is used to analyze seasonal variability of mesoscale circulation in the Tatar Strait of the Japan Sea. The model domain is a vast area including the northern Japan Sea, Okhotsk Sea and adjacent region in the Pacific Ocean. A numerical experiment with a horizontal 1/18° resolution has been carried out under realistic meteorological conditions from the ECMWF ERA-40 reanalysis with restoring of surface temperature and salinity. The simulated seasonal variability of both the current system and mesoscale eddy dynamics in the Tatar Strait is in a good agreement with temperature and salinity distributions of oceanographic observation data collected during various seasons and years. Two general circulation regimes in the Strait have been found. The circulation regime changes from summer to winter due to seasonal change of the North Asian Monsoon. On a synoptic time scale, the similar change of the circulation regime occurs due to change of the southeastern wind to the northwestern one when the meteorological situation with an anticyclone over the Okhotsk Sea changes to that with a strong cyclone. The Lagrangian maps illustrate seasonal changes in direction of the main currents and in polarity and location of mesoscale eddies in the Strait.

NEXT, a HPXe TPC for neutrinoless double beta decay searches

NASA Astrophysics Data System (ADS)

Gómez-Cadenas, J. J.; Martín-Albo, J.

2008-11-01

The next-generation experiments for neutrinoless double beta decay searches are a major challenge, since the detectors have to fulfill conflicting requirements: they have to be very massive and scalable; very sensitive to the signature of the ββ processes, and simultaneously impose extremely stringent limits on the copious backgrounds. A high-pressure gaseous Xenon TPC may be the ideal detector for this purpose: the isotope 136Xe is almost 9% of natural Xenon and enrichment by centrifugation is a relatively easy technology as demonstrated by the EXO collaboration; the detector can be extrapolated to large masses; energy resolution in gas is expected to be at the level of 1% FWHM at Qββ this fact, combined with the very long life of the ββ2ν mode accounts for negligible backgrounds of intrinsic origin up to masses of the order of 1 ton. The detector is fully active and the gas can be continuously re-circulated and purified, which, together with the existence of a kinematical signature gives an extra handle against backgrounds. NEXT (Neutrino Experiment with a Xenon TPC) is an on-going project that aims to build a 100 kg HPXe TPC at a pressure of ~10 bar. The experiment has already been aproved by the scientific committee of the Canfranc Underground Laboratory (LSC), in Spain, for the initial R&D phase. The NEXT Collaboration has defined an ambitious roadmap for the next five years: an initial phase of R&D during 2 years will be used to decide the technology (MicroMegas, GEMs. APDs. PMTs, etc.); in 3 years a first prototype (NEXT-10) will be constructed; followed by NEXT-100 in 5 years. A special grant (Consolider-Ingenio 2010) from the Ministry of Science of Spain will fund the experiment during this period. The Collaboration is composed by the leading Spanish groups in experimental neutrino and underground physics. The general ideas behind neutrinoless double beta decay searches with a HPXe TPC are discussed in this note.

Optimisation of a parallel ocean general circulation model

NASA Astrophysics Data System (ADS)

Beare, M. I.; Stevens, D. P.

1997-10-01

This paper presents the development of a general-purpose parallel ocean circulation model, for use on a wide range of computer platforms, from traditional scalar machines to workstation clusters and massively parallel processors. Parallelism is provided, as a modular option, via high-level message-passing routines, thus hiding the technical intricacies from the user. An initial implementation highlights that the parallel efficiency of the model is adversely affected by a number of factors, for which optimisations are discussed and implemented. The resulting ocean code is portable and, in particular, allows science to be achieved on local workstations that could otherwise only be undertaken on state-of-the-art supercomputers.

Tropical disturbances in relation to general circulation modeling

NASA Technical Reports Server (NTRS)

Estoque, M. A.

1982-01-01

The initial results of an evaluation of the performance of the Goddard Laboratory of Atmospheric Simulation general circulation model depicting the tropical atmosphere during the summer are presented. Because the results show the existence of tropical wave disturbances throughout the tropics, the characteristics of synoptic disturbances over Africa were studied and a synoptic case study of a selected disturbance in this area was conducted. It is shown that the model is able to reproduce wave type synoptic disturbances in the tropics. The findings show that, in one of the summers simulated, the disturbances are predominantly closed vortices; in another summer, the predominant disturbances are open waves.

Heat balance statistics derived from four-dimensional assimilations with a global circulation model

NASA Technical Reports Server (NTRS)

Schubert, S. D.; Herman, G. F.

1981-01-01

The reported investigation was conducted to develop a reliable procedure for obtaining the diabatic and vertical terms required for atmospheric heat balance studies. The method developed employs a four-dimensional assimilation mode in connection with the general circulation model of NASA's Goddard Laboratory for Atmospheric Sciences. The initial analysis was conducted with data obtained in connection with the 1976 Data Systems Test. On the basis of the results of the investigation, it appears possible to use the model's observationally constrained diagnostics to provide estimates of the global distribution of virtually all of the quantities which are needed to compute the atmosphere's heat and energy balance.

Wireless Technology in the Library: The RIT Experience: Overview of the Project.

ERIC Educational Resources Information Center

Pitkin, Pat

2001-01-01

Provides an overview of a project at RIT (Rochester Institute of Technology) that experimented with wireless technology, including laptop computers that circulate within the library building. Discusses project requirements, including ease of use, low maintenance, and low cost; motivation, including mobility; implementation; and benefits to the…

"The living picture": on the circulation of microscope-slide knowledge in 1903.

PubMed

Gaycken, Oliver

2013-01-01

Microscope slides allowed preparations to circulate among scientific and educational contexts. An extension of the circulation of microscope slides was how they became part of lantern exhibition culture. This article considers an early example of the adoption of microscope lantern show conventions by another medium, the cinema. E Martin Duncan, who was employed by Charles Urban to produce a series of popular-science films beginning in 1903, brought his experience with microphotography to bear on the challenge of adapting cinema to the purpose of public instruction. Duncan's first series of films, entitled "The Unseen World," demonstrated both profound links to the display tradition of the lantern lecture as well as the transformation of that tradition by the cinema's representational possibilities.

Spaceborne studies of ocean circulation

NASA Technical Reports Server (NTRS)

Patzert, W. C.

1984-01-01

The history and near-term future of ocean remote sensing to study ocean circulation are examined. Seasat provided the first-ever global data sets of sea surface topography (altimeter) and marine winds (scatterometer) and laid the foundation for the next generation of satellite missions planned for the late 1980s. The future missions are the next generation of altimeter and scatterometer to be flown aboard TOPEX (TOPography EXperiment) and NROSS (Navy Remote Sensing System), respectively. The data from these satellites will be coordinated with measurements made at sea to determine the driving forces of ocean circulation and to study the oceans' role in climate variability. The significance of such studies to such matters as climatic changes, fisheries, commerce, waste disposal, and national defense is noted.

Eastern Pacific cooling and Atlantic overturning circulation during the last deglaciation.

PubMed

Kienast, Markus; Kienast, Stephanie S; Calvert, Stephen E; Eglinton, Timothy I; Mollenhauer, Gesine; François, Roger; Mix, Alan C

2006-10-19

Surface ocean conditions in the equatorial Pacific Ocean could hold the clue to whether millennial-scale global climate change during glacial times was initiated through tropical ocean-atmosphere feedbacks or by changes in the Atlantic thermohaline circulation. North Atlantic cold periods during Heinrich events and millennial-scale cold events (stadials) have been linked with climatic changes in the tropical Atlantic Ocean and South America, as well as the Indian and East Asian monsoon systems, but not with tropical Pacific sea surface temperatures. Here we present a high-resolution record of sea surface temperatures in the eastern tropical Pacific derived from alkenone unsaturation measurements. Our data show a temperature drop of approximately 1 degrees C, synchronous (within dating uncertainties) with the shutdown of the Atlantic meridional overturning circulation during Heinrich event 1, and a smaller temperature drop of approximately 0.5 degrees C synchronous with the smaller reduction in the overturning circulation during the Younger Dryas event. Both cold events coincide with maxima in surface ocean productivity as inferred from 230Th-normalized carbon burial fluxes, suggesting increased upwelling at the time. From the concurrence of equatorial Pacific cooling with the two North Atlantic cold periods during deglaciation, we conclude that these millennial-scale climate changes were probably driven by a reorganization of the oceans' thermohaline circulation, although possibly amplified by tropical ocean-atmosphere interaction as suggested before.

Constraints on ocean circulation at the Paleocene-Eocene Thermal Maximum from neodymium isotopes

NASA Astrophysics Data System (ADS)

Abbott, April N.; Haley, Brian A.; Tripati, Aradhna K.; Frank, Martin

2016-04-01

Global warming during the Paleocene-Eocene Thermal Maximum (PETM) ˜ 55 million years ago (Ma) coincided with a massive release of carbon to the ocean-atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role of changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites to reconstruct past deep-ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth Nd isotopes and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for initiation and recovery of the ocean-atmosphere system associated with the PETM.

Destroyer Engineered Operating Cycle (DDEOC), System Maintenance Analysis DDG-37 Class, Salt Water Circulating System SMA 37-106-256, Review of Experience

DTIC Science & Technology

1978-07-01

horizontally mounted, single-end suction, single- stage centrifugal pumps. The rotating elements are mounted on the shaft of the driving motor, and the pump...annual open-and-inspect requirement for MIP E-17/296-21, MRC 21 A14V A. Industrial Facility Improvements -- None IMA Improvements -- None Intergrated ...Circulating Pump, Warren Pumps, Inc., NAVSHIPS 347-3146, January 1959. 4. Technical Manual - Horizontal Close-Co!;pled Pumps Sea (Salt) Water

[The physiology of the isolated dog pancreas--the influence of the actual blood glucose level on the blood circulation in the pancreas].

PubMed

Hempfling, H; Husemann, B

1975-06-01

1. Glucose loading tests were undertaken on isolated pancreas or pancreas-duodenal preparations. 2. In 75% of cases a vasodilatation can be observed which leads to enhanced blood circulation under constant pressure in the isolated organ. 3. This vasodilatation persists until the level of blood sugar has normalized. 4. The experiment being carried out on an isolated organ, external factors such as the vagus nerve, do not become active.

Development and analysis of closed cycle circulator elements. Final report 31 Jul 978-31 May 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shih, C.C.; Karr, G.R.; Perkins, J.F.

1980-05-01

A series of experiments with various flow rates of laser gas and coolants under several levels of energy inputs has been conducted on the Army Closed Cycle Circulator for pulsed EDL to collect sufficient data for flow calibration and coefficient determination. Verification of the theoretical models depicting the functions of the heat exchangers in maintaining the thermal balance in the flow through the steady and transient states are made through comparison with results of the experimental analysis.

A Weak Constraint 4D-Var Assimilation System for the Navy Coastal Model Using the Representer Method

DTIC Science & Technology

2013-01-01

the help of the Parametric Fortrai compiler (PFC), Erwig et al. 2007 . Some general circulation models of the complexity of NCOM have seen 1 similar...the Mir general circulation model (MITgcm, Marotzke et al. 1999) also used in the ECCO consortium assimilation experiments ( Stammer et al. 2002...using the« inverse Regional Ocean Modeling System (IROMS, Di Lorenzo et al. 2007 ) with horizontal resolutions of 10 and 30km. The CCS is a large

Technical report series on global modeling and data assimilation. Volume 1: Documentation of the Goddard Earth Observing System (GEOS) General Circulation Model, version 1

NASA Technical Reports Server (NTRS)

Suarez, Max J. (Editor); Takacs, Lawrence L.; Molod, Andrea; Wang, Tina

1994-01-01

This technical report documents Version 1 of the Goddard Earth Observing System (GEOS) General Circulation Model (GCM). The GEOS-1 GCM is being used by NASA's Data Assimilation Office (DAO) to produce multiyear data sets for climate research. This report provides a documentation of the model components used in the GEOS-1 GCM, a complete description of model diagnostics available, and a User's Guide to facilitate GEOS-1 GCM experiments.

The Dermis as a Delivery Site of Trypanosoma brucei for Tsetse Flies

PubMed Central

Caljon, Guy; Van Reet, Nick; De Trez, Carl; Vermeersch, Marjorie; Pérez-Morga, David; Van Den Abbeele, Jan

2016-01-01

Tsetse flies are the sole vectors of Trypanosoma brucei parasites that cause sleeping sickness. Our knowledge on the early interface between the infective metacyclic forms and the mammalian host skin is currently highly limited. Glossina morsitans flies infected with fluorescently tagged T. brucei parasites were used in this study to initiate natural infections in mice. Metacyclic trypanosomes were found to be highly infectious through the intradermal route in sharp contrast with blood stream form trypanosomes. Parasite emigration from the dermal inoculation site resulted in detectable parasite levels in the draining lymph nodes within 18 hours and in the peripheral blood within 42 h. A subset of parasites remained and actively proliferated in the dermis. By initiating mixed infections with differentially labeled parasites, dermal parasites were unequivocally shown to arise from the initial inoculum and not from a re-invasion from the blood circulation. Scanning electron microscopy demonstrated intricate interactions of these skin-residing parasites with adipocytes in the connective tissue, entanglement by reticular fibers of the periadipocytic baskets and embedment between collagen bundles. Experimental transmission experiments combined with molecular parasite detection in blood fed flies provided evidence that dermal trypanosomes can be acquired from the inoculation site immediately after the initial transmission. High resolution thermographic imaging also revealed that intradermal parasite expansion induces elevated skin surface temperatures. Collectively, the dermis represents a delivery site of the highly infective metacyclic trypanosomes from which the host is systemically colonized and where a proliferative subpopulation remains that is physically constrained by intricate interactions with adipocytes and collagen fibrous structures. PMID:27441553

Resuscitator’s perceptions and time for corrective ventilation steps during neonatal resuscitation☆

PubMed Central

Sharma, Vinay; Lakshminrusimha, Satyan; Carrion, Vivien; Mathew, Bobby

2016-01-01

Background The 2010 neonatal resuscitation program (NRP) guidelines incorporate ventilation corrective steps (using the mnemonic – MRSOPA) into the resuscitation algorithm. The perception of neonatal providers, time taken to perform these maneuvers or the effectiveness of these additional steps has not been evaluated. Methods Using two simulated clinical scenarios of varying degrees of cardiovascular compromise –perinatal asphyxia with (i) bradycardia (heart rate – 40 min−1) and (ii) cardiac arrest, 35 NRP certified providers were evaluated for preference to performing these corrective measures, the time taken for performing these steps and time to onset of chest compressions. Results The average time taken to perform ventilation corrective steps (MRSOPA) was 48.9 ± 21.4 s. Providers were less likely to perform corrective steps and proceed directly to endotracheal intubation in the scenario of cardiac arrest as compared to a state of bradycardia. Cardiac compressions were initiated significantly sooner in the scenario of cardiac arrest 89 ± 24 s as compared to severe bradycardia 122 ± 23 s, p < 0.0001. There were no differences in the time taken to initiation of chest compressions between physicians or mid-level care providers or with the level of experience of the provider. Conclusions Effective ventilation of the lungs with corrective steps using a mask is important in most cases of neonatal resuscitation. Neonatal resuscitators prefer early endotracheal intubation and initiation of chest compressions in the presence of asystolic cardiac arrest. Corrective ventilation steps can potentially postpone initiation of chest compressions and may delay return of spontaneous circulation in the presence of severe cardiovascular compromise. PMID:25796996

Quinine-induced disseminated intravascular coagulation.

PubMed

Spearing, R L; Hickton, C M; Sizeland, P; Hannah, A; Bailey, R R

Recurrent disseminated intravascular coagulation occurred in 3 women after ingestion of quinine tablets for cramp. All had circulating quinine-dependent antibodies to platelets and in 2 there was initial evidence of antibody consumption, with low titres that rose steeply over the next few days and remained high for many months.

Column formation and hysteresis in a two-fluid tornado

NASA Astrophysics Data System (ADS)

Sharifullin, B. R.; Naumov, I. V.; Herrada, M. A.; Shtern, V. N.

2018-03-01

This experimental and numerical study addresses a flow of water and sunflower oil. This flow is driven by the rotating lid in a sealed vertical cylinder. The experiments were performed in a glass container with a radius of 45 mm and a height of 45 mm with the water volume fraction of 20%. Different densities and immiscibility of liquids provide the stable and sharp interface. At the rest, the interface is flat and horizontal. As the rotation speeds up, a new water-flow cell emerges near the bottom center. This cell expands and occupies almost the entire water domain while the initial water circulation shrinks into a thin layer adjacent to the interface. The water, rising near the container axis, strongly deforms the interface (upward near the axis and downward near the sidewall). A new oil-flow cell emerges above the interface near the axis. This cell disappears as the interface approaches the lid. The water separates from the sidewall, reaches the lid, and forms a column. As the rotation is decreased, the scenario reverses, but the flow states differ from those for the increasing rotation, i.e., a hysteresis is observed. The numerical simulations agree with the experiment and help explain the flow metamorphoses.

A "NIRS" death experience: a reduction in cortical oxygenation by time-resolved near-infrared spectroscopy preceding cardiac arrest.

PubMed

Lanks, C; Kim, C B; Rossiter, H B

2017-09-08

Near-infrared spectroscopy (NIRS) has been used effectively post-cardiac-arrest to gauge adequacy of resuscitation and predict the likelihood of achieving a return of spontaneous circulation. However, preempting hemodynamic collapse is preferable to achieving ROSC through advanced cardiac life support. Minimizing "time down" without end-organ perfusion has always been a central pillar of ACLS. In many critically ill patients there is a prolonged phase of end-organ hypoperfusion preceding loss of palpable pulses and initiation of ACLS. Due to the relative infrequency of in-hospital cardiac arrest, NIRS has not previously evaluated the period immediately prior to hemodynamic collapse. Here we report a young man who suffered a pulseless electrical activity (PEA) arrest while cortical oxygenation was monitored using time-resolved near-infrared spectroscopy. The onset of cortical deoxygenation preceded the loss of palpable pulses by 15 min, suggesting that TRS-NIRS monitoring might provide a means of preempting PEA arrest. Our experience with this patient represents a promising new direction for continuous NIRS monitoring and has the potential to not only predict clinical outcomes, but affect them to the patient's benefit as well.

Circulating nucleic acids as possible damage-associated molecular patterns in different stages of renal failure.

PubMed

Kocić, Gordana; Radenkovic, Sonja; Cvetkovic, Tatjana; Cencic, Avrelija; Carluccio, Francesco; Musovic, Dijana; Nikolić, Goran; Jevtović-Stoimenov, Tatjana; Sokolović, Dusan; Milojkovic, Boban; Basic, Jelena; Veljkovic, Andrej; Stojanović, Svetlana

2010-05-01

Chronic renal failure (CRF) is a condition associated with the risk of cardiovascular complications. Systemic inflammatory response, initiated by the pathogen-associated molecular-pattern (PAMP) molecules, exerts many similarities with the damage-associated molecular-pattern (DAMP) molecule-induced systemic response. Up to now, a number of DAMP molecules were identified. We hypothesized that the available circulating nucleic acids, acting as DAMPs, may modulate immunoinflammatory reaction in CRF. Patients with the different stages of chronic kidney disease, kidney transplantation, and patients on dialysis were included in the study. Obtained results about higher concentration of circulating ribonucleic acid (RNA), according to the stages of kidney diseases, may contribute to the hypothesis that damaged kidney tissue releases nucleic acids. Circulating RNAs expressed maximal absorbance peak at 270 nm in spectrophotometric scan analysis, which corresponded to polyC, compared to different standard samples. During in vitro conditions, by using the culture of human residential macrophages, circulating RNA isolated from patients with IV-V-stage renal diseases, patients on hemodialysis, and patients who underwent renal transplantation were able to significantly change signal transduction proteins related to inflammation and antiviral response. They significantly increased the intracellular concentration of active nuclear transcription factor nuclear factor kappa B (NF-kappaB), interferon regulatory factors (IRF)-3, and IRF-7 and significantly decreased melanoma differentiation-associated protein-5 (MDA-5) and p38. In this way, it seems that circulating RNA, acting as DAMP, may contribute to the mechanisms of additional inflammatory reaction, possible immune destruction, and decreased antiviral response, related to complications in kidney diseases.

A Study of Subseasonal Predictability of the Atmospheric Circulation Low-frequency Modes based on SL-AV forecasts

NASA Astrophysics Data System (ADS)

Kruglova, Ekaterina; Kulikova, Irina; Khan, Valentina; Tischenko, Vladimir

2017-04-01

The subseasonal predictability of low-frequency modes and the atmospheric circulation regimes is investigated based on the using of outputs from global Semi-Lagrangian (SL-AV) model of the Hydrometcentre of Russia and Institute of Numerical Mathematics of Russian Academy of Science. Teleconnection indices (AO, WA, EA, NAO, EU, WP, PNA) are used as the quantitative characteristics of low-frequency variability to identify zonal and meridional flow regimes with focus on control distribution of high impact weather patterns in the Northern Eurasia. The predictability of weekly and monthly averaged indices is estimated by the methods of diagnostic verification of forecast and reanalysis data covering the hindcast period, and also with the use of the recommended WMO quantitative criteria. Characteristics of the low frequency variability have been discussed. Particularly, it is revealed that the meridional flow regimes are reproduced by SL-AV for summer season better comparing to winter period. It is shown that the model's deterministic forecast (ensemble mean) skill at week 1 (days 1-7) is noticeably better than that of climatic forecasts. The decrease of skill scores at week 2 (days 8-14) and week 3( days 15-21) is explained by deficiencies in the modeling system and inaccurate initial conditions. It was noticed the slightly improvement of the skill of model at week 4 (days 22-28), when the condition of atmosphere is more determined by the flow of energy from the outside. The reliability of forecasts of monthly (days 1-30) averaged indices is comparable to that at week 1 (days 1-7). Numerical experiments demonstrated that the forecast accuracy can be improved (thus the limit of practical predictability can be extended) through the using of probabilistic approach based on ensemble forecasts. It is shown that the quality of forecasts of the regimes of circulation like blocking is higher, than that of zonal flow.

Idealized WRF model sensitivity simulations of sea breeze types and their effects on offshore windfields

NASA Astrophysics Data System (ADS)

Steele, C. J.; Dorling, S. R.; von Glasow, R.; Bacon, J.

2013-01-01

The behaviour and characteristics of the marine component of sea breeze cells have received little attention relative to their onshore counterparts. Yet there is a growing interest and dependence on the offshore wind climate from, for example, a wind energy perspective. Using idealized model experiments, we investigate the sea breeze circulation at scales which approximate to those of the southern North Sea, a region of major ongoing offshore wind farm development. We also contrast the scales and characteristics of the pure and the little known corkscrew and backdoor sea breeze types, where the type is pre-defined by the orientation of the synoptic scale flow relative to the shoreline. We find, crucially, that pure sea breezes, in contrast to corkscrew and backdoor types, can lead to substantial wind speed reductions offshore and that the addition of a second eastern coastline emphasises this effect through generation of offshore "calm zones". The offshore extent of all sea breeze types is found to be sensitive to both the influence of Coriolis acceleration and to the boundary layer scheme selected. These extents range, for example for a pure sea breeze produced in a 2 m s-1 offshore gradient wind, from 0 km to 21 km between the Mellor-Yamada-Nakanishi-Niino and the Yonsei State University schemes respectively. The corkscrew type restricts the development of a backdoor sea breeze on the opposite coast and is also capable of traversing a 100 km offshore domain even under high along-shore gradient wind speed (>15 m s-1) conditions. Realistic variations in sea surface skin temperature and initializing vertical thermodynamic profile do not significantly alter the resulting circulation, though the strengths of the simulated sea breezes are modulated if the effective land-sea thermal contrast is altered. We highlight how sea breeze impacts on circulation need to be considered in order to improve the accuracy of both assessments of the offshore wind energy climate and forecasts of wind energy output.

Sensitivity of Boreal-Summer Circulation and Precipitation to Atmospheric Aerosols in Selected Regions. Part 2; The Americas

NASA Technical Reports Server (NTRS)

Wilcox, E. M.; Sud, Y. C.; Walker, G.

2009-01-01

Aerosol perturbations over selected land regions are imposed in Version-4 of the Goddard Earth Observing System (GEOS-4) general circulation model (GCM) to assess the influence of increasing aerosol concentrations on regional circulation patterns and precipitation in four selected regions: India, Africa, and North and South America. Part 1 of this paper addresses the responses to aerosol perturbations in India and Africa. This paper presents the same for aerosol perturbations over the Americas. GEOS-4 is forced with prescribed aerosols based on climatological data, which interact with clouds using a prognostic scheme for cloud microphysics including aerosol nucleation of water and ice cloud hydrometeors. In clear-sky conditions the aerosols interact with radiation. Thus the model includes comprehensive physics describing the aerosol direct and indirect effects on climate (hereafter ADE and AIE respectively). Each simulation is started from analyzed initial conditions for 1 May and was integrated through June-July-August of each of the six years: 1982 1987 to provide a 6-ensemble set. Results are presented for the difference between simulations with double the climatological aerosol concentration and one-half the climatological aerosol concentration for three experiments: two where the ADE and AIE are applied separately and one in which both the ADE and AIE are applied. The ADE and AIE both yield reductions in net radiation at the top of the atmosphere and surface while the direct absorption of shortwave radiation contributes a net radiative heating in the atmosphere. A large net heating of the atmosphere is also apparent over the subtropical North Atlantic Ocean that is attributable to the large aerosol perturbation imposed over Africa. This atmospheric warming and the depression of the surface pressure over North America contribute to a northward shift of the inter-Tropical Convergence Zone over northern America, an increase in precipitation over Central America and the Caribbean, and an enhancement of convergence in the North American monsoon region.

E-selectin ligand-1 controls circulating prostate cancer cell rolling/adhesion and metastasis

PubMed Central

Yasmin-Karim, Sayeda; King, Michael R.; Messing, Edward M.; Lee, Yi-Fen

2014-01-01

Circulating prostate cancer (PCa) cells preferentially roll and adhere on bone marrow vascular endothelial cells, where abundant E-selectin and stromal cell-derived factor 1 (SDF-1) are expressed, subsequently initiating a cascade of activation events that eventually lead to the development of metastases. To elucidate the roles of circulating PCa cells' rolling and adhesion behaviors in cancer metastases, we applied a dynamic cylindrical flow-based microchannel device that is coated with E-selectin and SDF-1, mimicking capillary endothelium. Using this device we captured a small fraction of rolling PCa cells. These rolling cells display higher static adhesion ability, more aggressive cancer phenotypes and stem-like properties. Importantly, mice received rolling PCa cells, but not floating PCa cells, developed cancer metastases. Genes coding for E-selectin ligands and genes associated with cancer stem cells and metastasis were elevated in rolling PCa cells. Knock down of E-selectin ligand 1(ESL-1), significantly impaired PCa cells' rolling capacity and reduced cancer aggressiveness. Moreover, ESL-1 activates RAS and MAP kinase signal cascade, consequently inducing the downstream targets. In summary, circulating PCa cells' rolling capacity contributes to PCa metastasis, and that is in part controlled by ESL-1. PMID:25301730

Generating and manipulating quantized vortices on-demand in a Bose-Einstein condensate: A numerical study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gertjerenken, B.; Kevrekidis, P. G.; Carretero-González, R.

Here, we numerically investigate an experimentally viable method for generating and manipulating on-demand several vortices in a highly oblate atomic Bose-Einstein condensate (BEC) in order to initialize complex vortex distributions for studies of vortex dynamics. The method utilizes moving laser beams to generate, capture, and transport vortices inside and outside the BEC. This methodology is examined in detail and shows a wide parameter range of applicability for the prototypical two-vortex case, as well as case examples of producing and manipulating several vortices for which there is no net circulation, corresponding to equal numbers of positive and negative circulation vortices, andmore » cases for which there is one net quantum of circulation. We also find that the presence of dissipation can help stabilize the pinning of the vortices on their respective laser beam pinning sites. Finally, we illustrate how to utilize laser beams as repositories that hold large numbers of vortices and how to deposit individual vortices in a sequential fashion in the repositories in order to construct superfluid flows about the repository beams with several quanta of circulation.« less

Generating and manipulating quantized vortices on-demand in a Bose-Einstein condensate: A numerical study

DOE PAGES

Gertjerenken, B.; Kevrekidis, P. G.; Carretero-González, R.; ...

2016-02-01

Here, we numerically investigate an experimentally viable method for generating and manipulating on-demand several vortices in a highly oblate atomic Bose-Einstein condensate (BEC) in order to initialize complex vortex distributions for studies of vortex dynamics. The method utilizes moving laser beams to generate, capture, and transport vortices inside and outside the BEC. This methodology is examined in detail and shows a wide parameter range of applicability for the prototypical two-vortex case, as well as case examples of producing and manipulating several vortices for which there is no net circulation, corresponding to equal numbers of positive and negative circulation vortices, andmore » cases for which there is one net quantum of circulation. We also find that the presence of dissipation can help stabilize the pinning of the vortices on their respective laser beam pinning sites. Finally, we illustrate how to utilize laser beams as repositories that hold large numbers of vortices and how to deposit individual vortices in a sequential fashion in the repositories in order to construct superfluid flows about the repository beams with several quanta of circulation.« less

Circulation of core collection monographs in an academic medical library.

PubMed

Schmidt, C M; Eckerman, N L

2001-04-01

Academic medical librarians responsible for monograph acquisition face a challenging task. From the plethora of medical monographs published each year, academic medical librarians must select those most useful to their patrons. Unfortunately, none of the selection tools available to medical librarians are specifically intended to assist academic librarians with medical monograph selection. The few short core collection lists that are available are intended for use in the small hospital or internal medicine department library. As these are the only selection tools available, however, many academic medical librarians spend considerable time reviewing these collection lists and place heavy emphasis on the acquisition of listed books. The study reported here was initiated to determine whether the circulation of listed books in an academic library justified the emphasis placed on the acquisition of these books. Circulation statistics for "listed" and "nonlisted" books in the hematology (WH) section of Indiana University School of Medicine's Ruth Lilly Medical Library were studied. The average circulation figures for listed books were nearly two times as high as the corresponding figures for the WH books in general. These data support the policies of those academic medical libraries that place a high priority on collection of listed books.

Effects of one's sex and sex hormones on sympathetic responses to chemoreflex activation.

PubMed

Usselman, Charlotte W; Steinback, Craig D; Shoemaker, J Kevin

2016-03-01

What is the topic of this review? This review summarizes sex-dependent differences in the sympathetic responses to chemoreflex activation, with a focus on the role of circulating sex hormones on the sympathetic outcomes. What advances does it highlight? The importance of circulating sex hormones for the regulation of sympathetic nerve activity in humans has only recently begun to be elucidated, and few studies have examined this effect during chemoreflex regulation. We review recent studies indicating that changes in circulating sex hormones are associated with alterations to chemoreflex-driven increases in sympathetic activity and highlight those areas which require further study. Sex-dependent differences in baseline sympathetic nerve activity are established, but little information exists on the influence of sex on sympathetic activation during chemoreflex stimulation. In this article, we review the evidence for the effect of sex on chemoreflex-driven increases in sympathetic nerve activity. We also review recent studies which indicate that changes in circulating sex hormones, as initiated by the menstrual cycle and hormonal contraceptive use, elicit notable changes in the muscle sympathetic activation during chemoreflex stimulation. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Circulation of core collection monographs in an academic medical library

PubMed Central

Schmidt, Cynthia M.; Eckerman, Nancy L.

2001-01-01

Academic medical librarians responsible for monograph acquisition face a challenging task. From the plethora of medical monographs published each year, academic medical librarians must select those most useful to their patrons. Unfortunately, none of the selection tools available to medical librarians are specifically intended to assist academic librarians with medical monograph selection. The few short core collection lists that are available are intended for use in the small hospital or internal medicine department library. As these are the only selection tools available, however, many academic medical librarians spend considerable time reviewing these collection lists and place heavy emphasis on the acquisition of listed books. The study reported here was initiated to determine whether the circulation of listed books in an academic library justified the emphasis placed on the acquisition of these books. Circulation statistics for “listed” and “nonlisted” books in the hematology (WH) section of Indiana University School of Medicine's Ruth Lilly Medical Library were studied. The average circulation figures for listed books were nearly two times as high as the corresponding figures for the WH books in general. These data support the policies of those academic medical libraries that place a high priority on collection of listed books. PMID:11337947

The momentum constraints on the shallow meridional circulation associated with the marine ITCZ

NASA Astrophysics Data System (ADS)

Dixit, Vishal; Srinivasan, J.

2017-12-01

Recent studies have shown that the shallow meridional circulation (SMC) coexists with the deep circulation in the marine ITCZ. The SMC has been assumed to be forced by strong meridional gradients of Sea Surface Temperature (SST) which affect the atmosphere under hydrostatic balance. In this paper, we present a new viewpoint that the shallow meridional circulation is a part of circulation that forms when the marine ITCZ is located away from the equator. To support this view, we have used reanalysis data over east Pacific ocean to show that the shallow meridional circulation is absent when the ITCZ is located near the equator while it is strong to the south of the ITCZ when the ITCZ is located away from the equator. To further support this view, we have conducted idealized aquaplanet experiments by shifting SST maximum polewards to simulate the observed contrast in the meridional circulation associated with near equatorial and off-equatorial ITCZ. The detailed momentum budget of the flow above the boundary layer shows that, to the south of an off-equatorial ITCZ, the dominant balance between the Coriolis force and the advection of relative vorticity by the mean flow leads to cancellation of the planetary rotational effects. As a result, the net rotational effects experienced by the diverging flow above the boundary layer are negligible and a shallow meridional flow along the pressure gradients is generated. This dominant balance does not occur in the aquaplanet GCM when the ITCZ forms near the equator.

The East Asian Atmospheric Water Cycle and Monsoon Circulation in the Met Office Unified Model

NASA Astrophysics Data System (ADS)

Rodríguez, José M.; Milton, Sean F.; Marzin, Charline

2017-10-01

In this study the low-level monsoon circulation and observed sources of moisture responsible for the maintenance and seasonal evolution of the East Asian monsoon are examined, studying the detailed water budget components. These observational estimates are contrasted with the Met Office Unified Model (MetUM) climate simulation performance in capturing the circulation and water cycle at a variety of model horizontal resolutions and in fully coupled ocean-atmosphere simulations. We study the role of large-scale circulation in determining the hydrological cycle by analyzing key systematic errors in the model simulations. MetUM climate simulations exhibit robust circulation errors, including a weakening of the summer west Pacific Subtropical High, which leads to an underestimation of the southwesterly monsoon flow over the region. Precipitation and implied diabatic heating biases in the South Asian monsoon and Maritime Continent region are shown, via nudging sensitivity experiments, to have an impact on the East Asian monsoon circulation. By inference, the improvement of these tropical biases with increased model horizontal resolution is hypothesized to be a factor in improvements seen over East Asia with increased resolution. Results from the annual cycle of the hydrological budget components in five domains show a good agreement between MetUM simulations and ERA-Interim reanalysis in northern and Tibetan domains. In simulations, the contribution from moisture convergence is larger than in reanalysis, and they display less precipitation recycling over land. The errors are closely linked to monsoon circulation biases.

High sub-seasonal variability in water volume transports, revealed through a new ocean monitoring initiative using autonomous gliders

NASA Astrophysics Data System (ADS)

Heslop, E.; Ruiz, S.; Allen, J.; Tintoré, J.

2012-04-01

One of the clear challenges facing oceanography today is to define variability in ocean processes at a seasonal and sub-seasonal scale, in order to clearly identify the signature of both natural large-scale climatic oscillations and the long-term trends brought about by the human-induced change in atmospheric composition. Without visibility of this variance, which helps to determine the margins of significance for long-term trends and decipher cause and effect, the inferences drawn from sparse data points can be misleading. The cyclonic basin scale circulation pattern in the Western Mediterranean has long been known; the role/contribution that processes in the Balearic Basin play in modifying this is less well defined. The Balearic Channels (channels between the Balearic Islands) are constriction points on this basin scale circulation that appear to exert a controlling influence on the north/south exchange of water masses. Understanding the variability in current flows through these channels is important, not just for the transport of heat and salt, but also for ocean biology that responds to physical variability at the scale of that variability. Earlier studies at a seasonal scale identified; an interannual summer/winter variation of 1 Sv in the strength of the main circulation pattern and a high cruise-to-cruise variability in the pattern and strength of the flows through the channels brought about by mesoscale activity. Initial results using new high-resolution data from glider based monitoring missions across the Ibiza Channel (the main exchange channel in the Balearic Basin), combined with ship and contemporaneous satellite data, indicate surprisingly high and rapid changes in the flows of surface and intermediate waters imposed on the broad seasonal cycle. To date the data suggests that there are three potential 'modes' of water volume transport, generated from the interplay between basin and mesoscale circulation. We will review the concept of transport modes as seen through the earlier seasonal ship based studies and demonstrate that the scales of variability captured by the glider monitoring provides a unique view of variability in this circulation system, which is as high on a weekly timescale as the previously identified seasonal cycle.

Can increased poleward oceanic heat flux explain the warm Cretaceous climate?

NASA Astrophysics Data System (ADS)

Schmidt, Gavin A.; Mysak, Lawrence A.

1996-10-01

The poleward transport of heat in the mid-Cretaceous (100 Ma) is examined using an idealized coupled ocean-atmosphere model. The oceanic component consists of two zonally averaged basins representing the proto-Pacific and proto-Indian oceans and models the dynamics of the meridional thermohaline circulation. The atmospheric component is a simple energy and moisture balance model which includes the diffusive meridional transport of sensible heat and moisture. The ocean model is spun up with a variety of plausible Cretaceous surface temperature and salinity profiles, and a consistent atmosphere is objectively derived based on the resultant sea surface temperature and the surface heat and freshwater fluxes. The coupled model does not exhibit climate drift. Multiple equilibria of the coupled model are found that break the initial symmetry of the ocean circulation; several of these equilibria have one-cell (northern or southern sinking) thermohaline circulation patterns. Two main classes of circulation are found: circulations where the densest water is relatively cool and is formed at the polar latitudes and circulations where the densest water is warm, but quite saline, and the strongest sinking occurs at the tropics. In all cases, significant amounts of warm, saline bottom water are formed in the proto-Indian basin which modify the deepwater characteristics in the larger (proto-Pacific) basin. Temperatures in the deep ocean are warm, 10°-17°C, in agreement with benthic foraminiferal oxygen isotope data. The poleward transport of heat in the modeled Cretaceous oceans is larger than in some comparable models of the present day thermohaline circulation and significantly larger than estimates of similar processes in the present-day ocean. It is consistently larger in the polar sinking cases when compared with that seen in the tropical sinking cases, but this represents an increase of only 10%. The largest increase over present-day model transports is in the atmospheric latent heat transport, where an increased hydrological cycle (especially in the tropical sinking cases) contributes up to an extra 1 PW of poleward heat transport. Better constraints on the oceanic deepwater circulation during this period are necessary before the meridional circulation can be unambiguously described.

Impact of the ongoing Amazonian deforestation on local precipitation: A GCM simulation study

NASA Technical Reports Server (NTRS)

Walker, G. K.; Sud, Y. C.; Atlas, R.

1995-01-01

Numerical simulation experiments were conducted to delineate the influence of in situ deforestation data on episodic rainfall by comparing two ensembles of five 5-day integrations performed with a recent version of the Goddard Laboratory for Atmospheres General Circulation Model (GCM) that has a simple biosphere model (SiB). The first set, called control cases, used the standard SiB vegetation cover (comprising 12 biomes) and assumed a fully forested Amazonia, while the second set, called deforestation cases, distinguished the partially deforested regions of Amazonia as savanna. Except for this difference, all other initial and prescribed boundary conditions were kept identical in both sets of integrations. The differential analyses of these five cases show the following local effects of deforestation. (1) A discernible decrease in evapotranspiration of about 0.80 mm/d (roughly 18%) that is quite robust in the averages for 1-, 2-, and 5-day forecasts. (2) A decrease in precipitation of about 1.18 mm/d (roughly 8%) that begins to emerge even in 1-2 day averages and exhibits complex evolution that extends downstream with the winds. (3) A significant decrease in the surface drag force (as a consequence of reduced surface roughness of deforested regions) that, in turn, affects the dynamical structure of moisture convergence and circulation. The surface winds increase significantly during the first day, and thereafter the increase is well maintained even in the 2- and 5-day averages.

Live imaging using a FRET glucose sensor reveals glucose delivery to all cell types in the Drosophila brain.

PubMed

Volkenhoff, Anne; Hirrlinger, Johannes; Kappel, Johannes M; Klämbt, Christian; Schirmeier, Stefanie

2018-04-01

All complex nervous systems are metabolically separated from circulation by a blood-brain barrier (BBB) that prevents uncontrolled leakage of solutes into the brain. Thus, all metabolites needed to sustain energy homeostasis must be transported across this BBB. In invertebrates, such as Drosophila, the major carbohydrate in circulation is the disaccharide trehalose and specific trehalose transporters are expressed by the glial BBB. Here we analyzed whether glucose is able to contribute to energy homeostasis in Drosophila. To study glucose influx into the brain we utilized a genetically encoded, FRET-based glucose sensor expressed in a cell type specific manner. When confronted with glucose all brain cells take up glucose within two minutes. In order to characterize the glucose transporter involved, we studied Drosophila Glut1, the homologue of which is primarily expressed by the BBB-forming endothelial cells and astrocytes in the mammalian nervous system. In Drosophila, however, Glut1 is expressed in neurons and is not found at the BBB. Thus, Glut1 cannot contribute to initial glucose uptake from the hemolymph. To test whether gap junctional coupling between the BBB forming cells and other neural cells contributes to glucose distribution we assayed these junctions using RNAi experiments and only found a minor contribution of gap junctions to glucose metabolism. Our results provide the entry point to further dissect the mechanisms underlying glucose distribution and offer new opportunities to understand brain metabolism. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of propagation mechanisms of stimulation-induced fractures in rocks

NASA Astrophysics Data System (ADS)

Krause, Michael; Renner, Joerg

2016-04-01

Effectivity of geothermal energy production depends crucially on the heat exchange between the penetrated hot rock and the circulating water. Hydraulic stimulation of rocks at depth intends to create a network of fractures that constitutes a large area for exchange. Two endmembers of stimulation products are typically considered, tensile hydro-fractures that propagate in direction of the largest principal stress and pre-existing faults that are sheared when fluid pressure reduces the effective normal stress acting on them. The understanding of the propagation mechanisms of fractures under in-situ conditions is still incomplete despite intensive research over the last decades. Wing-cracking has been suggested as a mechanism of fracture extension from pre-existent faults with finite length that are induced to shear. The initiation and extension of the wings is believed to be in tensile mode. Open questions concern the variability of the nominal material property controlling tensile fracture initiation and extension, the mode I facture toughness KIC, with in-situ conditions, e.g., its mean-stress dependence. We investigated the fracture-propagation mechanism in different rocks (sandstones and granites) under varying conditions mimicking those representative for geothermal systems. To determine KIC-values we performed 3-point bending experiments. We varied the confining pressure, the piston velocity, and the position of the chevron notch relative to the loading configuration. Additional triaxial experiments at a range of confining pressures were performed to study wing crack propagation from artificial flaws whose geometrical characteristics, i.e., length, width, and orientation relative to the axial load are varied. We monitored acoustic emissions to constrain the spacio-temporal evolution of the fracturing. We found a significant effect of the length of the artificial flaw and the confining pressure on wing-crack initiation but did not observe a systematic dependence of wing-crack initiation on the orientation of the initial flaw in the range of tested angles. In fact, wings do not develop for artificial flaws shorter than 3 mm. The force required to initiate wing cracking increases with increasing confining pressure as does the apparent fracture toughness. So called ``anti-wing cracks'' were observed too, probably an artifact of the geometrical constraints imposed on the sample in a conventional triaxial compression test.

Studies on the liver sequestration of lymphocytes bearing membrane-associated galactose-terminal glycoconjugates: reversal with agents that effectively compete for the asialoglycoprotein receptor.

PubMed

Samlowski, W E; Spangrude, G J; Daynes, R A

1984-10-15

The removal of "effete" glycoproteins from the circulation represents a proposed physiologic role for the hepatocyte asialoglycoprotein receptor. Our experiments support the hypothesis that this receptor may also be directly involved in the removal from the circulation of cells bearing asialoglycoconjugates. We report that the enhanced liver localization of neuraminidase-treated lymphocytes can be competitively inhibited by the coinjection of asialofetuin (ASF). Fetuin itself was without effect. Competitive inhibition of the liver receptor allowed normal localization to lymphoid tissues of the enzyme-treated lymphocytes, a condition which persisted as long as free ASF was present in the circulation. Our studies support the concept that cell surface carbohydrates play an important role in the tissue distribution of circulating lymphocytes. The process of thymocyte maturation, bone marrow transplantation, and the adoptive immunotherapy with continuous T-cell lines represent conditions where recirculation potential may be influenced by the presence of galactose terminal glycoconjugates.

Multidecadal Weakening of Indian Summer Monsoon Circulation Induces an Increasing Northern Indian Ocean Sea Level

NASA Astrophysics Data System (ADS)

Swapna, P.; Jyoti, J.; Krishnan, R.; Sandeep, N.; Griffies, S. M.

2017-10-01

North Indian Ocean sea level has shown significant increase during last three to four decades. Analyses of long-term climate data sets and ocean model sensitivity experiments identify a mechanism for multidecadal sea level variability relative to global mean. Our results indicate that North Indian Ocean sea level rise is accompanied by a weakening summer monsoon circulation. Given that Indian Ocean meridional heat transport is primarily regulated by the annual cycle of monsoon winds, weakening of summer monsoon circulation has resulted in reduced upwelling off Arabia and Somalia and decreased southward heat transport, and corresponding increase of heat storage in the North Indian Ocean. These changes in turn lead to increased retention of heat and increased thermosteric sea level rise in the North Indian Ocean, especially in the Arabian Sea. These findings imply that rising North Indian Ocean sea level due to weakening of monsoon circulation demands adaptive strategies to enable a resilient South Asian population.

Global warming hiatus contributed to the increased occurrence of intense tropical cyclones in the coastal regions along East Asia.

PubMed

Zhao, Jiuwei; Zhan, Ruifen; Wang, Yuqing

2018-04-16

The recent global warming hiatus (GWH) was characterized by a La Niña-like cooling in the tropical Eastern Pacific accompanied with the Indian Ocean and the tropical Atlantic Ocean warming. Here we show that the recent GWH contributed significantly to the increased occurrence of intense tropical cyclones in the coastal regions along East Asia since 1998. The GWH associated sea surface temperature anomalies triggered a pair of anomalous cyclonic and anticyclonic circulations and equatorial easterly anomalies over the Northwest Pacific, which favored TC genesis and intensification over the western Northwest Pacific but suppressed TC genesis and intensification over the southeastern Northwest Pacific due to increased vertical wind shear and anticyclonic circulation anomalies. Results from atmospheric general circulation model experiments demonstrate that the Pacific La Niña-like cooling dominated the Indian Ocean and the tropical Atlantic Ocean warming in contributing to the observed GWH-related anomalous atmospheric circulation over the Northwest Pacific.

Increased beta-adrenergic responsiveness induced by 14 days exposure to simulated microgravity

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Polet, J. L.; Engelke, K. A.; Hoffler, G. W.; Lane, L. D.; Blomqvist, C. G.

1995-01-01

Increased sensitivity of end-organ responses to neuroendocrine stimuli as a result of prolonged exposure to the relative inactivity of microgravity has recently been hypothesized. This notion is based on the inverse relationship between circulating norepinephrine and beta-adrenoreceptor sensitivity. The beta-adrenoreceptor activity is reduced in individuals who have elevated plasma norepinephrine as a result of regular exposure to upright posture and physical exercise. In contrast, adrenoreceptor hypersensitivity has been reported in patients with dysautonomias in which circulating catecholamines are absent or reduced. Taken together, these studies and the observation that circulating plasma norepinephrine has been reduced during spaceflight and in groundbased simulations of microgravity prompt the suggestion that adrenoreceptor hypersensitivity may be a consequence of the adaptation to spaceflight. We conducted an experiment designed to measure cardiovascular responses to adrenoreceptor agonists in human subjects before and after prolonged exposure to 6 deg head-down tilt (HDT) to test the hypothesis that adaptation to microgravity increases adrenoreceptor responsiveness, and that this adaptation is associated with reduced levels of circulating norepinephrine.

What Drives the Variability of the Atlantic Water Circulation in the Arctic Ocean?

NASA Astrophysics Data System (ADS)

Lique, C.; Johnson, H. L.

2016-02-01

The Atlantic Water (AW) layer in the Arctic Basin is isolated from the atmosphere by the overlaying surface layer; yet observations of the AW pan-Arctic boundary current have revealed that the velocities in this layer exhibit significant variations on all timescales. Here, analysis of a global ocean/sea ice model hindcast, complemented by experiments performed with an idealized process model, are used to investigate what controls the variability of AW circulation, with a focus on the role of wind forcing. The AW circulation carries the imprint of wind variations, both remotely over the Nordic and Barents seas where they force variability on the AW inflow to the Arctic Basin, and locally over the Arctic Basin through the forcing of the wind-driven Beaufort gyre, which modulates and transfers the wind variability to the AW layer. Our results further suggest that understanding variability in the large amount of heat contained within the AW layer requires a better understanding of the circulation within both AW and surface layers.

Characteristics of oily sludge combustion in circulating fluidized beds.

PubMed

Zhou, Lingsheng; Jiang, Xiumin; Liu, Jianguo

2009-10-15

Incineration of oily sludge in circulating fluidized beds may be an effective way for its management in some cases. The objective of the present paper is to investigate combustion characteristics of oily sludge, which would be helpful and useful for the design and simulation of a circulating fluidized bed. Firstly, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of its pyrolysis products. Secondly, an experiment for measuring of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved from the experimental results. Finally, the combustion characteristics of oily sludge was studied in a lab-scale circulating fluidized bed, which could obtain some information about the location of release and combustion of the volatiles.

The Twist Tensor Nuclear Norm for Video Completion.

PubMed

Hu, Wenrui; Tao, Dacheng; Zhang, Wensheng; Xie, Yuan; Yang, Yehui

2017-12-01

In this paper, we propose a new low-rank tensor model based on the circulant algebra, namely, twist tensor nuclear norm (t-TNN). The twist tensor denotes a three-way tensor representation to laterally store 2-D data slices in order. On one hand, t-TNN convexly relaxes the tensor multirank of the twist tensor in the Fourier domain, which allows an efficient computation using fast Fourier transform. On the other, t-TNN is equal to the nuclear norm of block circulant matricization of the twist tensor in the original domain, which extends the traditional matrix nuclear norm in a block circulant way. We test the t-TNN model on a video completion application that aims to fill missing values and the experiment results validate its effectiveness, especially when dealing with video recorded by a nonstationary panning camera. The block circulant matricization of the twist tensor can be transformed into a circulant block representation with nuclear norm invariance. This representation, after transformation, exploits the horizontal translation relationship between the frames in a video, and endows the t-TNN model with a more powerful ability to reconstruct panning videos than the existing state-of-the-art low-rank models.

Assimilating NOAA SST data into BSH operational circulation model for North and Baltic Seas

NASA Astrophysics Data System (ADS)

Losa, Svetlana; Schroeter, Jens; Nerger, Lars; Janjic, Tijana; Danilov, Sergey; Janssen, Frank

A data assimilation (DA) system is developed for BSH operational circulation model in order to improve forecast of current velocities, sea surface height, temperature and salinity in the North and Baltic Seas. Assimilated data are NOAA sea surface temperature (SST) data for the following period: 01.10.07 -30.09.08. All data assimilation experiments are based on im-plementation of one of the so-called statistical DA methods -Singular Evolutive Interpolated Kalman (SEIK) filter, -with different ways of prescribing assumed model and data errors statis-tics. Results of the experiments will be shown and compared against each other. Hydrographic data from MARNET stations and sea level at series of tide gauges are used as independent information to validate the data assimilation system. Keywords: Operational Oceanography and forecasting

Simulation of the global ocean thermohaline circulation with an eddy-resolving INMIO model configuration

NASA Astrophysics Data System (ADS)

Ushakov, K. V.; Ibrayev, R. A.

2017-11-01

In this paper, the first results of a simulation of the mean World Ocean thermohaline characteristics obtained by the INMIO ocean general circulation model configured with 0.1 degree resolution in a 5-year long numerical experiment following the CORE-II protocol are presented. The horizontal and zonal mean distributions of the solution bias against the WOA09 data are analyzed. The seasonal cycle of heat content at a specified site of the North Atlantic is also discussed. The simulation results demonstrate a clear improvement in the quality of representation of the upper ocean compared to the results of experiments with 0.5 and 0.25 degree model configurations. Some remaining biases of the model solution and possible ways of their overcoming are highlighted.

Underage Drinking and the Drinking Age

ERIC Educational Resources Information Center

Main, Carla T.

2009-01-01

The problem of underage drinking on college campuses has been brewing for many years to the continued vexation of higher education administrators. In 2008, John McCardell, president emeritus of Middlebury College, began to circulate for signature a public statement among colleagues titled "The Amethyst Initiative," which calls for elected…

Soundstop. An Experimental Student Housing Study.

ERIC Educational Resources Information Center

Ontario Dept. of Education, Toronto. School Planning and Building Research Section.

The design development of a housing facility for deaf and blind students is reviewed in considerable detail. Initially traditional architectural solutions to the creation of dormitory space and accompanying circulation patterns are examined for their effect upon the lives of the inhabitants. The subsequent design progression which is presented is…

Invasive plants in Arizona's forests and woodlands

Treesearch

Alix Rogstad; Tom DeGomez; Carol Hull Sieg

2007-01-01

Climate is critically linked to vegetation dynamics at many different spatial and temporal scales across the desert Southwest. Small-scale, short duration monsoon season thunderstorms can bring much needed precipitation to small patches of vegetation or can initiate widespread flooding. Long-term variations in climate related to ocean circulation patterns can create...

Extratropical response to Fast and Slow episodes of Madden-Julian Oscillation in observation and using intervention experiments with CFSv2

NASA Astrophysics Data System (ADS)

Yadav, P.; Straus, D. M.

2017-12-01

The Madden-Julian Oscillation (MJO) is a potential source of predictability in the extratropics in extended range weather forecasting. The nature of MJO is sporadic and therefore, the mid-latitude response may depend on the nature of the MJO event, in particular the phase speed. We discuss the results of our observational and modeling study of mid-latitude circulation response to Fast and Slow MJO episodes using wintertime ERA-Interim reanalysis data and the CFSv2 coupled model of NOAA. The observational study shows that the mid-latitude response to different propagating speeds is not the same. The propagation speed is defined by the time the OLR takes to propagate from phase 3 to phase 6. The mid-latitude response is assessed in terms of composite maps and frequency of occurrence of robust circulation regimes. Fast episode composite anomalies of 500hPa height show a developing Rossby wave in the mid-Pacific with downstream propagation through MJO phases 2- 4. Development of NAO+ teleconnection pattern is stronger in Slow that in Fast MJO episodes, and occurs with a greater time lag after MJO heating is in the Indian Ocean (phase 3). Previous results find an increase in occurrence of NAO- regime following phase 6. We have found that much of this behavior is due to the slow episodes. Based on these observational results, intervention experiments using CFSv2 are designed to better understand the impact of heating/cooling and to estimate mid-latitude response to Fast and Slow MJO episodes. The added heating experiments consist of 31 year reforecasts for December 1 initial conditions from CFS reanalysis (1980-2011) in which the identical MJO evolution of three-dimensional diabatic heating has been added, thus producing fast and slow MJO episodes with well-defined phase speeds. We will discuss the results of these experiments with a focus on understanding the role of phase speed and interference in setting up the response, and to understand the mechanisms that distinguish fast and slow types of response We will also discuss the diagnostics using Predictable Component Analysis to distinguish the signal forced by common diabatic heating signal from noise, and weather regime response to fast and slow MJO using cluster analysis.

Zebrafish as an early stage screening tool to study the systemic circulation of nanoparticulate drug delivery systems in vivo.

PubMed

Sieber, Sandro; Grossen, Philip; Detampel, Pascal; Siegfried, Salome; Witzigmann, Dominik; Huwyler, Jörg

2017-10-28

Nanomedicines have gained much attention for the delivery of small molecules or nucleic acids as treatment options for many diseases. However, the transfer from experimental systems to in vivo applications remains a challenge since it is difficult to assess their circulation behavior in the body at an early stage of drug discovery. Thus, innovative and improved concepts are urgently needed to overcome this issue and to close the gap between empiric nanoparticle design, in vitro assessment, and first in vivo experiments using rodent animal models. This study was focused on the zebrafish as a vertebrate screening model to assess the circulation in blood and extravasation behavior of nanoparticulate drug delivery systems in vivo. To validate this novel approach, monodisperse preparations of fluorescently labeled liposomes with similar size and zeta potential were injected into transgenic zebrafish lines expressing green fluorescent protein in their vasculature. Phosphatidylcholine-based lipids differed by fatty acid chain length and saturation. Circulation behavior and vascular distribution pattern were evaluated qualitatively and semi-quantitatively using image analysis. Liposomes composed of lipids with lower transition temperature (<28°C) as well as PEGylated liposomes showed longer circulation times and extravasation. In contrast, liposomes composed of lipids with transition temperatures>28°C bound to venous parts of the vasculature. This circulation patterns in the zebrafish model did correlate with published and experimental pharmacokinetic data from mice and rats. Our findings indicate that the zebrafish model is a useful vertebrate screening tool for nanoparticulate drug delivery systems to predict their in vivo circulation behavior with respect to systemic circulation time and exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

ISP33 standard problem on the PACTEL facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purhonen, H.; Kouhia, J.; Kalli, H.

ISP33 is the first OECD/NEA/CSNI standard problem related to VVER type of pressurized water reactors. The reference reactor of the PACTEL test facility, which was used to carry out the ISP33 experiment, is the VVER-440 reactor, two of which are located near the Finnish city of Loviisa. The objective of the ISP33 test was to study the natural circulation behaviour of VVER-440 reactors at different coolant inventories. Natural circulation was considered as a suitable phenomenon to focus on by the first VVER related ISP due to its importance in most accidents and transients. The behaviour of the natural circulation wasmore » expected to be different compared to Western type of PWRs as a result of the effect of horizontal steam generators and the hot leg loop seals. This ISP was conducted as a blind problem. The experiment was started at full coolant inventory. Single-phase natural circulation transported the energy from the core to the steam generators. The inventory was then reduced stepwise at about 900 s intervals draining 60 kg each time from the bottom of the downcomer. the core power was about 3.7% of the nominal value. The test was terminated after the cladding temperatures began to rise. ATHLET, CATHARE, RELAP5 (MODs 3, 2.5 and 2), RELAP4/MOD6, DINAMIKA and TECH-M4 codes were used in 21 pre- and 20 posttest calculations submitted for the ISP33.« less

The impact of environmental inertial stability on the secondary circulation of axisymmetric tropical cyclones

NASA Astrophysics Data System (ADS)

O'Neill, M. E.; Chavas, D. R.

2017-12-01

In f-plane numerical simulations and analytical theory, tropical cyclones completely recycle their exhausted outflow air back into the boundary layer. This low-angular momentum air must experience cyclonic torque at the sea surface for cyclone to reach equilibrium. On Earth, however, it is not clear that tropical cyclones recycle all of the outflow air in a closed secondary circulation, and strong asymmetric outflow-jet interactions suggest that much of the air may be permanently evacuated from the storm over its lifetime. The fraction of outflow air that is returned to the near-storm boundary layer is in part a function of the environmental inertial stability, which controls the size and strength of the upper anticyclone. We run a suite of idealized axisymmetric tropical cyclone simulations at constant latitude while varying the outer domain's inertial stability profile. Fixing the latitude allows the gradient wind balance of the storm core to remain constant except for changes due to the far environment. By varying both the outer inertial stability and its location with respect to the Rossby radius of deformation, we show how the tropical cyclone's area-of-influence is controlled by the nature and strength of the upper anticyclone. Parcel tracking additionally demonstrates the likelihood of outflow air parcels to be quickly re-consumed by the secondary circulation as a function of inertial stability. These experiments demonstrate the sensitivity of the tropical cyclone's secondary circulation, typically assumed to be closed, to the dynamics of the far environment.

Air Circulation and Heat Exchange under Reduced Pressures

NASA Astrophysics Data System (ADS)

Rygalov, Vadim; Wheeler, Raymond; Dixon, Mike; Hillhouse, Len; Fowler, Philip

Low pressure atmospheres were suggested for Space Greenhouses (SG) design to minimize sys-tem construction and re-supply materials, as well as system manufacturing and deployment costs. But rarified atmospheres modify heat exchange mechanisms what finally leads to alter-ations in thermal control for low pressure closed environments. Under low atmospheric pressures (e.g., lower than 25 kPa compare to 101.3 kPa for normal Earth atmosphere), convection is becoming replaced by diffusion and rate of heat exchange reduces significantly. During a period from 2001 to 2009, a series of hypobaric experiments were conducted at Space Life Sciences Lab (SLSLab) NASA's Kennedy Space Center and the Department of Space Studies, University of North Dakota. Findings from these experiments showed: -air circulation rate decreases non-linearly with lowering of total atmospheric pressure; -heat exchange slows down with pressure decrease creating risk of thermal stress (elevated leaf tem-peratures) for plants in closed environments; -low pressure-induced thermal stress could be reduced by either lowering system temperature set point or increasing forced convection rates (circulation fan power) within certain limits; Air circulation is an important constituent of controlled environments and plays crucial role in material and heat exchange. Theoretical schematics and mathematical models are developed from a series of observations. These models can be used to establish optimal control algorithms for low pressure environments, such as a space greenhouse, as well as assist in fundamental design concept developments for these or similar habitable structures.

Transport on intermediate time scales in flows with cat's eye patterns

NASA Astrophysics Data System (ADS)

Pöschke, Patrick; Sokolov, Igor M.; Zaks, Michael A.; Nepomnyashchy, Alexander A.

2017-12-01

We consider the advection-diffusion transport of tracers in a one-parameter family of plane periodic flows where the patterns of streamlines feature regions of confined circulation in the shape of "cat's eyes," separated by meandering jets with ballistic motion inside them. By varying the parameter, we proceed from the regular two-dimensional lattice of eddies without jets to the sinusoidally modulated shear flow without eddies. When a weak thermal noise is added, i.e., at large Péclet numbers, several intermediate time scales arise, with qualitatively and quantitatively different transport properties: depending on the parameter of the flow, the initial position of a tracer, and the aging time, motion of the tracers ranges from subdiffusive to superballistic. We report on results of extensive numerical simulations of the mean-squared displacement for different initial conditions in ordinary and aged situations. These results are compared with a theory based on a Lévy walk that describes the intermediate-time ballistic regime and gives a reasonable description of the behavior for a certain class of initial conditions. The interplay of the walk process with internal circulation dynamics in the trapped state results at intermediate time scales in nonmonotonic characteristics of aging not captured by the Lévy walk model.

System analysis of the dynamic response of the coronary circulation to a sudden change in heart rate.

PubMed

Dankelman, J; Stassen, H G; Spaan, J A

1990-03-01

In this study the response of driving pressure/flow ration on an abrupt change in heart rate was analysed. The difference between the response obtained with constant pressure and constant flow perfusion was also studied. The responses show a fast initial reversed phase followed by a slow phase caused by regulation. To test whether the initial phase could be the result of mechanical changes in the coronary circulation, a model for regulation was extended by the addition of four different mechanical models originating from the literature. These extended models were able to explain the fast initial phase. However, the mechanical model consisting of an intramyocardial compliance (C = 0.08 ml mm Hg-1 100 g-1) with a variable venous resistance, and the model consisting of a waterfall and a small compliance (C = 0.007 ml mm Hg-1 100g-1) both explained these responses best. The analysis showed that there is no direct relationship between rate of change of vascular tone and rate of change of pressure/flow ratio. However, on the basis of the two extended models, it can be predicted that the half-time for the response of regulation to be complete is about 9s with constant pressure perfusion and 15 s with constant flow perfusion.

Summertime land-sea thermal contrast and atmospheric circulation over East Asia in a warming climate—Part I: Past changes and future projections

NASA Astrophysics Data System (ADS)

Kamae, Youichi; Watanabe, Masahiro; Kimoto, Masahide; Shiogama, Hideo

2014-11-01

Land-sea surface air temperature (SAT) contrast, an index of tropospheric thermodynamic structure and dynamical circulation, has shown a significant increase in recent decades over East Asia during the boreal summer. In Part I of this two-part paper, observational data and the results of transient warming experiments conducted using coupled atmosphere-ocean general circulation models (GCMs) are analyzed to examine changes in land-sea thermal contrast and the associated atmospheric circulation over East Asia from the past to the future. The interannual variability of the land-sea SAT contrast over the Far East for 1950-2012 was found to be tightly coupled with a characteristic tripolar pattern of tropospheric circulation over East Asia, which manifests as anticyclonic anomalies over the Okhotsk Sea and around the Philippines, and a cyclonic anomaly over Japan during a positive phase, and vice versa. In response to CO2 increase, the cold northeasterly winds off the east coast of northern Japan and the East Asian rainband were strengthened with the circulation pattern well projected on the observed interannual variability. These results are commonly found in GCMs regardless of future forcing scenarios, indicating the robustness of the East Asian climate response to global warming. The physical mechanisms responsible for the increase of the land-sea contrast are examined in Part II.

Effect of Anesthesia Carrier Gas on In-Vivo Circulation Times of Ultrasound Microbubble Contrast Agents in Rats

PubMed Central

Mullin, Lee; Gessner, Ryan; Kwan, James; Kaya, Mehmet; Borden, Mark A.; Dayton, Paul A.

2012-01-01

Purpose Microbubble contrast agents are currently implemented in a variety of both clinical and preclinical ultrasound imaging studies. The therapeutic and diagnostic capabilities of these contrast agents are limited by their short in-vivo lifetimes, and research to lengthen their circulation times is ongoing. In this manuscript, observations are presented from a controlled experiment performed to evaluate differences in circulation times for lipid shelled perfluorocarbon-filled contrast agents circulating within rodents as a function of inhaled anesthesia carrier gas. Methods The effects of two common anesthesia carrier gas selections - pure oxygen and medical air – were observed within five rats. Contrast agent persistence within the kidney was measured and compared for oxygen and air anesthesia carrier gas for six bolus contrast injections in each animal. Simulations were performed to examine microbubble behavior with changes in external environment gases. Results A statistically significant extension of contrast circulation time was observed for animals breathing medical air compared to breathing pure oxygen. Simulations support experimental observations and indicate that enhanced contrast persistence may be explained by reduced ventilation/perfusion mismatch and classical diffusion, in which nitrogen plays a key role by contributing to the volume and diluting other gas species in the microbubble gas core. Conclusion: Using medical air in place of oxygen as the carrier gas for isoflurane anesthesia can increase the circulation lifetime of ultrasound microbubble contrast agents. PMID:21246710

Deformation structure analysis of material at fatigue on the basis of the vector field

NASA Astrophysics Data System (ADS)

Kibitkin, Vladimir V.; Solodushkin, Andrey I.; Pleshanov, Vasily S.

2017-12-01

In the paper, spatial distributions of deformation, circulation, and shear amplitudes and shear angles are obtained from the displacement vector field measured by the DIC technique. This vector field and its characteristics of shears and vortices are given as an example of such approach. The basic formulae are also given. The experiment shows that honeycomb deformation structures can arise in the center of a macrovortex at developed plastic flow. The spatial distribution of local circulation and shears is discovered, which coincides with the deformation structure but their amplitudes are different. The analysis proves that the spatial distribution of shear angles is a result of maximum tangential and normal stresses. The anticlockwise circulation of most local vortices obeys the normal Gaussian law in the area of interest.

3.0 Tesla high spatial resolution contrast-enhanced magnetic resonance angiography (CE-MRA) of the pulmonary circulation: initial experience with a 32-channel phased array coil using a high relaxivity contrast agent.

PubMed

Nael, Kambiz; Fenchel, Michael; Krishnam, Mayil; Finn, J Paul; Laub, Gerhard; Ruehm, Stefan G

2007-06-01

To evaluate the technical feasibility of high spatial resolution contrast-enhanced magnetic resonance angiography (CE-MRA) with highly accelerated parallel acquisition at 3.0 T using a 32-channel phased array coil, and a high relaxivity contrast agent. Ten adult healthy volunteers (5 men, 5 women, aged 21-66 years) underwent high spatial resolution CE-MRA of the pulmonary circulation. Imaging was performed at 3 T using a 32-channel phase array coil. After intravenous injection of 1 mL of gadobenate dimeglumine (Gd-BOPTA) at 1.5 mL/s, a timing bolus was used to measure the transit time from the arm vein to the main pulmonary artery. Subsequently following intravenous injection of 0.1 mmol/kg of Gd-BOPTA at the same rate, isotropic high spatial resolution data sets (1 x 1 x 1 mm3) CE-MRA of the entire pulmonary circulation were acquired using a fast gradient-recalled echo sequence (TR/TE 3/1.2 milliseconds, FA 18 degrees) and highly accelerated parallel acquisition (GRAPPA x 6) during a 20-second breath hold. The presence of artifact, noise, and image quality of the pulmonary arterial segments were evaluated independently by 2 radiologists. Phantom measurements were performed to assess the signal-to-noise ratio (SNR). Statistical analysis of data was performed by using Wilcoxon rank sum test and 2-sample Student t test. The interobserver variability was tested by kappa coefficient. All studies were of diagnostic quality as determined by both observers. The pulmonary arteries were routinely identified up to fifth-order branches, with definition in the diagnostic range and excellent interobserver agreement (kappa = 0.84, 95% confidence interval 0.77-0.90). Phantom measurements showed significantly lower SNR (P < 0.01) using GRAPPA (17.3 +/- 18.8) compared with measurements without parallel acquisition (58 +/- 49.4). The described 3 T CE-MRA protocol in addition to high T1 relaxivity of Gd-BOPTA provides sufficient SNR to support highly accelerated parallel acquisition (GRAPPA x 6), resulting in acquisition of isotopic (1 x 1 x 1 mm3) voxels over the entire pulmonary circulation in 20 seconds.

A review of the Southern Oscillation - Oceanic-atmospheric circulation changes and related rainfall anomalies

NASA Technical Reports Server (NTRS)

Kousky, V. E.; Kagano, M. T.; Cavalcanti, I. F. A.

1984-01-01

The region of South America is emphasized in the present consideration of the Southern Oscillation (SO) oceanic and atmospheric circulation changes. The persistence of climate anomalies associated with El Nino-SO events is due to strong atmosphere-ocean coupling. Once initiated, the SO follows a certain sequence of events with clearly defined effects on tropical and subtropical rainfall. Excessive rainfall related to the SO in the central and eastern Pacific, Peru, Ecuador, and southern Brazil, are complemented by drought in Australia, Indonesia, India, West Africa, and northeast Brazil. El Nino-SO events are also associated with dramatic changes in the tropospheric flow pattern over a broad area of both hemispheres.

A Newton-Krylov solver for fast spin-up of online ocean tracers

NASA Astrophysics Data System (ADS)

Lindsay, Keith

2017-01-01

We present a Newton-Krylov based solver to efficiently spin up tracers in an online ocean model. We demonstrate that the solver converges, that tracer simulations initialized with the solution from the solver have small drift, and that the solver takes orders of magnitude less computational time than the brute force spin-up approach. To demonstrate the application of the solver, we use it to efficiently spin up the tracer ideal age with respect to the circulation from different time intervals in a long physics run. We then evaluate how the spun-up ideal age tracer depends on the duration of the physics run, i.e., on how equilibrated the circulation is.

Inkjet-Print Micromagnet Array on Glass Slides for Immunomagnetic Enrichment of Circulating Tumor Cells

PubMed Central

Chen, Peng; Huang, Yu-Yen; Bhave, Gauri; Hoshino, Kazunori; Zhang, Xiaojing

2015-01-01

We report an inkjet-printed microscale magnetic structure that can be integrated on regular glass slides for the immunomagnetic screening of rare Circulating Tumor Cells (CTCs). CTCs detach from the primary tumor site, circulate with the bloodstream, and initiate the cancer metastasis process. Therefore, a liquid biopsy in the form of capturing and analyzing CTCs may provide key information for cancer prognosis and diagnosis. Inkjet printing technology provides a non-contact, layer-by-layer and mask-less approach to deposit defined magnetic patterns on an arbitrary substrate. Such thin film patterns, when placed in an external magnetic field, significantly enhance the attractive force in the near-field close to the CTCs to facilitate the separation. We demonstrated the efficacy of the inkjet-print micromagnet array integrated immunomagnetic assay in separating COLO205 (human colorectal cancer cell line) from whole blood samples. The micromagnets increased the capture efficiency by 26% compared with using plain glass slide as the substrate. PMID:26289942

Integrated and spectral energetics of the GLAS general circulation model

NASA Technical Reports Server (NTRS)

Tenenbaum, J.

1982-01-01

Integrated and spectral error energetics of the GLAS General circulation model are compared with observations for periods in January 1975, 1976, and 1977. For two cases the model shows significant skill in predicting integrated energetics quantities out to two weeks, and for all three cases, the integrated monthly mean energetics show qualitative improvements over previous versions of the model in eddy kinetic energy and barotropic conversions. Fundamental difficulties remain with leakage of energy to the stratospheric level, particularly above strong initial jet streams associated in part with regions of steep terrain. The spectral error growth study represents the first comparison of general circulation model spectral energetics predictions with the corresponding observational spectra on a day by day basis. The major conclusion is that eddy kinetics energy can be correct while significant errors occur in the kinetic energy of wavenumber 3. Both the model and observations show evidence of single wavenumber dominance in eddy kinetic energy and the correlation of spectral kinetics and potential energy.

A Pacific Ocean general circulation model for satellite data assimilation

NASA Technical Reports Server (NTRS)

Chao, Y.; Halpern, D.; Mechoso, C. R.

1991-01-01

A tropical Pacific Ocean General Circulation Model (OGCM) to be used in satellite data assimilation studies is described. The transfer of the OGCM from a CYBER-205 at NOAA's Geophysical Fluid Dynamics Laboratory to a CRAY-2 at NASA's Ames Research Center is documented. Two 3-year model integrations from identical initial conditions but performed on those two computers are compared. The model simulations are very similar to each other, as expected, but the simulations performed with the higher-precision CRAY-2 is smoother than that with the lower-precision CYBER-205. The CYBER-205 and CRAY-2 use 32 and 64-bit mantissa arithmetic, respectively. The major features of the oceanic circulation in the tropical Pacific, namely the North Equatorial Current, the North Equatorial Countercurrent, the South Equatorial Current, and the Equatorial Undercurrent, are realistically produced and their seasonal cycles are described. The OGCM provides a powerful tool for study of tropical oceans and for the assimilation of satellite altimetry data.

Circulating parathyroid hormone and calcitonin in rats after spaceflight

NASA Technical Reports Server (NTRS)

Arnaud, Sara B.; Fung, Paul; Popova, Irina A.; Morey-Holton, Emily R.; Grindeland, Richard E.

1992-01-01

Parathyroid hormone and calcithonin, two major calcium-regulating hormones, were measured in the plasma of five experimental groups of rats to evaluate postflight calcium homeostasis after the 14-day Cosmos 2044 flight. Parathyroid hormone values were slightly higher in the flight animals (F) than in the appropriate cage and diet controls (S) (44 +/- 21 vs 21 +/- 4 pg/ml, P less than 0.05), but they were the same as in the vivarium controls (V), which had different housing and feeding schedules. The difference in F and V (22 +/- 11 vs 49 +/- 16 pg/ml, P less than 0.05) was most likely due to failure of circulating calcitonin in F to show the normal age-dependent increase which was demonstrated in age-matched controls in a separate experiment. Basal values for parathyroid hormone and calcitonin were unchanged after 2 wk of hindlimb suspension, a flight simulation model, in age-matched and younger rats. From a time course experiment serum calcium was higher and parathyroid hormone lower after 4 wk than in ambulatory controls. Postflight circulating levels of parathyroid hormone appear to reflect disturbances in calcium homeostasis from impaired renal function of undetermined cause, whereas levels of calcitonin reflect depression of a normal growth process.

The Blalock-Taussig shunt revisited: a contemporary experience.

PubMed

McKenzie, E Dean; Khan, Muhammad S; Samayoa, Andres X; Vener, Daniel S; Ishak, Youstina M; Santos, Alexia B; Heinle, Jeffrey S; Fraser, Charles D

2013-04-01

The Blalock-Taussig shunt (BTS) was introduced 68 years ago before open repair of cyanotic congenital heart disease (CHD) was possible. The originally described technique has undergone many modifications but remains an integral component of the management of cyanotic CHD. We report our contemporary, single institution experience with the BTS. We performed a retrospective review of all patients treated with a BTS from June 1995 to December 2011. There were 730 BTS performed in 712 patients; 727 (99.6%) by interposition graft (modified). The BTS was predominantly right-sided (n = 657, 90%). Median age and weight at palliation were 8 days (range 0 days to 18.5 years) and 3.2 kg (1.5 to 51 kg). Median hospital length of stay was 16 days (range 0 to 347 days). There were 241 (33%) BTS performed as initial palliation for ultimate 2-ventricle (2V) circulation, 471 (65%) as part of staged palliation for patients with functionally univentricular lesions (1V), 6 (1%) as a part of 1.5-ventricle palliation, and 12 (1%) for Ebstein's anomaly. There were 473 (65%) BTS placed via sternotomy and the most common site of BTS was the right subclavian to right pulmonary artery (PA; n = 452, 62%). Hospital mortality was higher for BTS in 1V patients (1V 15% vs 2V 3%, p < 0.0001). Overall, 536 (73%) patients were bridged to complete repair or the second stage of 1V palliation after a median duration of 6.5 months (0 days to 15.3 years). Multivariable regression showed that sternotomy approach, use of cardiopulmonary bypass, innominate artery-PA shunt, and diagnosis of Ebstein's were risk factors for in-hospital mortality (p < 0.05). Although the BTS remains an important component of the surgical treatment of cyanotic congenital heart disease, patients with single ventricle circulation still face significant ongoing risk of mortality. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Morpho-functional aspects of the influence of procaine and diethylaminoethanol treatment on the immune system of rabbits.

PubMed

Bordea, M; Ardeleanu, C; Dolganiuc, A; Olinescu, A; Vrăbiescu, A

1998-01-01

Research was conducted in 24 male rabbits divided into three equal groups: 1) Controls; 2) Given daily i.m. injections with 15 mg/kg body weight of procaine for 30 days; 3) Given daily i.m. injections with 15 mg/kg body weight of diethylaminoethanol (DEAE) for 35 days. Blood samples were taken from the auricular vein to perform haematological investigations: before treatment, during treatment and for another 7 weeks after termination of treatment. At the end of the experiment, the animals were sacrificed in order to collect: 1) leukocytes, macrophages and lymphocytes from their spleen, for the purpose of immunological investigations, and 2) fragments of bone marrow (femur), thymus and spleen, for histopathological investigations. The result of haematological investigations indicated a statistically significant increase of circulating lymphocytes had occurred in rabbits treated with DEAE. There was an increase of percentage as well as of number of circulating lymphocytes. The increase occurred gradually in the course of treatment and continued after treatment was terminated. There were higher values than the initial ones by 44.4% and 66.4%, respectively, during the second and the fourth week after termination of treatment. Afterwards, the values started decreasing, so that by the end of the experiment (week 7 after termination), the values came close to those before treatment. Immunological findings indicated that T lymphocytes collected from rabbits treated with procaine or DEAE did not synthesize migration inhibition factors. Procaine and DEAE were found, in vitro, not to have a polyclonal stimulating effect over T lymphocytes. A study of blastic differentiation showed lymphocytes from treated rabbits to incorporate a larger amount of tritiated thymidine, by 52.6% in the procaine group and by 90% in the DEAE group, than those from non-treated rabbits. Histopathological examination indicated signs of a more intense activity in tissue formations involved in cell proliferation in the lymphoid organs collected from DEAE treated rabbits.

[William Harvey revisited ].

PubMed

Steinke, Hubert

2015-07-01

William Harvey's discovery of the circulation of the blood is often described as a product of the Scientific Revolution of the Seventeenth Century. Modern research has, however, shown thatHarvey followed the Aristotelian research tradition and thus tried to reveal the purpose of the organs through examination of various animals. His publication of 1628 has to be read as an argument of natural philosophy, or, more precisely, as a series of linked observations, experiments and philosophical reasonings from which the existence of circulation has to be deduced as a logical consequence. Harvey did not consider experiments as superior to philosophical reasoning nor intended he to create a new system of medicine. He believed in the vitality of the heart and the blood and rejected Francis Bacon's empirism and the mechanistic rationalism of Descartes. Harvey's contribution and originality lied less in his single observations and experiments but in the manner how he linked them with critical reasoning and how he accepted, presented and defended the ensuing radical findings.

Early administration of epinephrine (adrenaline) in patients with cardiac arrest with initial shockable rhythm in hospital: propensity score matched analysis

PubMed Central

Andersen, Lars W; Kurth, Tobias; Chase, Maureen; Berg, Katherine M; Cocchi, Michael N; Callaway, Clifton

2016-01-01

Objectives To evaluate whether patients who experience cardiac arrest in hospital receive epinephrine (adrenaline) within the two minutes after the first defibrillation (contrary to American Heart Association guidelines) and to evaluate the association between early administration of epinephrine and outcomes in this population. Design Prospective observational cohort study. Setting Analysis of data from the Get With The Guidelines-Resuscitation registry, which includes data from more than 300 hospitals in the United States. Participants Adults in hospital who experienced cardiac arrest with an initial shockable rhythm, including patients who had a first defibrillation within two minutes of the cardiac arrest and who remained in a shockable rhythm after defibrillation. Intervention Epinephrine given within two minutes after the first defibrillation. Main outcome measures Survival to hospital discharge. Secondary outcomes included return of spontaneous circulation and survival to hospital discharge with a good functional outcome. A propensity score was calculated for the receipt of epinephrine within two minutes after the first defibrillation, based on multiple characteristics of patients, events, and hospitals. Patients who received epinephrine at either zero, one, or two minutes after the first defibrillation were then matched on the propensity score with patients who were “at risk” of receiving epinephrine within the same minute but who did not receive it. Results 2978patients were matched on the propensity score, and the groups were well balanced. 1510 (51%) patients received epinephrine within two minutes after the first defibrillation, which is contrary to current American Heart Association guidelines. Epinephrine given within the first two minutes after the first defibrillation was associated with decreased odds of survival in the propensity score matched analysis (odds ratio 0.70, 95% confidence interval 0.59 to 0.82; P<0.001). Early epinephrine administration was also associated with a decreased odds of return of spontaneous circulation (0.71, 0.60 to 0.83; P<0.001) and good functional outcome (0.69, 0.58 to 0.83; P<0.001). Conclusion Half of patients with a persistent shockable rhythm received epinephrine within two minutes after the first defibrillation, contrary to current American Heart Association guidelines. The receipt of epinephrine within two minutes after the first defibrillation was associated with decreased odds of survival to hospital discharge as well as decreased odds of return of spontaneous circulation and survival to hospital discharge with a good functional outcome. PMID:27053638

Early administration of epinephrine (adrenaline) in patients with cardiac arrest with initial shockable rhythm in hospital: propensity score matched analysis.

PubMed

Andersen, Lars W; Kurth, Tobias; Chase, Maureen; Berg, Katherine M; Cocchi, Michael N; Callaway, Clifton; Donnino, Michael W

2016-04-06

To evaluate whether patients who experience cardiac arrest in hospital receive epinephrine (adrenaline) within the two minutes after the first defibrillation (contrary to American Heart Association guidelines) and to evaluate the association between early administration of epinephrine and outcomes in this population. Prospective observational cohort study. Analysis of data from the Get With The Guidelines-Resuscitation registry, which includes data from more than 300 hospitals in the United States. Adults in hospital who experienced cardiac arrest with an initial shockable rhythm, including patients who had a first defibrillation within two minutes of the cardiac arrest and who remained in a shockable rhythm after defibrillation. Epinephrine given within two minutes after the first defibrillation. Survival to hospital discharge. Secondary outcomes included return of spontaneous circulation and survival to hospital discharge with a good functional outcome. A propensity score was calculated for the receipt of epinephrine within two minutes after the first defibrillation, based on multiple characteristics of patients, events, and hospitals. Patients who received epinephrine at either zero, one, or two minutes after the first defibrillation were then matched on the propensity score with patients who were "at risk" of receiving epinephrine within the same minute but who did not receive it. 2978 patients were matched on the propensity score, and the groups were well balanced. 1510 (51%) patients received epinephrine within two minutes after the first defibrillation, which is contrary to current American Heart Association guidelines. Epinephrine given within the first two minutes after the first defibrillation was associated with decreased odds of survival in the propensity score matched analysis (odds ratio 0.70, 95% confidence interval 0.59 to 0.82; P<0.001). Early epinephrine administration was also associated with a decreased odds of return of spontaneous circulation (0.71, 0.60 to 0.83; P<0.001) and good functional outcome (0.69, 0.58 to 0.83; P<0.001). Half of patients with a persistent shockable rhythm received epinephrine within two minutes after the first defibrillation, contrary to current American Heart Association guidelines. The receipt of epinephrine within two minutes after the first defibrillation was associated with decreased odds of survival to hospital discharge as well as decreased odds of return of spontaneous circulation and survival to hospital discharge with a good functional outcome. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Circulating polymerase chain reaction chips utilizing multiple-membrane activation

NASA Astrophysics Data System (ADS)

Wang, Chih-Hao; Chen, Yi-Yu; Liao, Chia-Sheng; Hsieh, Tsung-Min; Luo, Ching-Hsing; Wu, Jiunn-Jong; Lee, Huei-Huang; Lee, Gwo-Bin

2007-02-01

This paper reports a new micromachined, circulating, polymerase chain reaction (PCR) chip for nucleic acid amplification. The PCR chip is comprised of a microthermal control module and a polydimethylsiloxane (PDMS)-based microfluidic control module. The microthermal control modules are formed with three individual heating and temperature-sensing sections, each modulating a specific set temperature for denaturation, annealing and extension processes, respectively. Micro-pneumatic valves and multiple-membrane activations are used to form the microfluidic control module to transport sample fluids through three reaction regions. Compared with other PCR chips, the new chip is more compact in size, requires less time for heating and cooling processes, and has the capability to randomly adjust time ratios and cycle numbers depending on the PCR process. Experimental results showed that detection genes for two pathogens, Streptococcus pyogenes (S. pyogenes, 777 bps) and Streptococcus pneumoniae (S. pneumoniae, 273 bps), can be successfully amplified using the new circulating PCR chip. The minimum number of thermal cycles to amplify the DNA-based S. pyogenes for slab gel electrophoresis is 20 cycles with an initial concentration of 42.5 pg µl-1. Experimental data also revealed that a high reproducibility up to 98% could be achieved if the initial template concentration of the S. pyogenes was higher than 4 pg µl-1. The preliminary results of the current paper were presented at the 19th IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2006), Istanbul, Turkey, 22-26 January, 2006.

Analysis of gene expression as relevant to cancer cells and circulating tumour cells.

PubMed

Friel, Anne M; Crown, John; O'Driscoll, Lorraine

2011-01-01

Current literature provides significant evidence to support the concept that there are limited subpopulations of cells within a solid tumour that have increased tumour-initiating potential relative to the total tumour population. Such tumour-initiating cells have been identified in leukaemia and in a variety of solid tumours using different combinations of cell surface markers, suggesting that a tumour-initiating cell heterogeneity exists for each specific tumour. These studies have been extended to endometrial cancer; and herein we present several experimental approaches, both in vitro and in vivo, that can be used to determine whether such populations exist, and if so, to characterize them. These methods are adaptable to the investigation of tumour-initiating cells from other tumour types.

Great New Insights from Failed Experiments, Unanticipated Results and Embracing Controversial Observations

NASA Technical Reports Server (NTRS)

Nuth, Joseph A., III; Johnson, Natasha M.; Ferguson, Frank T.; Rietmeijer, Frans J. M.; Hill, Hugh G. M.

2015-01-01

Experimental data and observations, whether telescopic or analytical, are never wrong, though data derived from such sources can be misinterpreted or applied inappropriately to derive conclusions that are incorrect. Given that nature always behaves according to the laws of physics and chemistry, rather than according to currently popular models and theories, experimental results should always be considered correct even when the results are far from those that one might initially expect. We discuss a number of cases where the results of experiments, even one carried out as a simple calibration measure, produced wildly different results that generally required many years of effort or contemplation to understand. On the positive side, exploration of the circumstances that produced the errant results often led to new and interesting insights concerning processes that might occur in natural environments and that were well worth the effort involved. Specifically, we show how an experiment that "failed" due to a broken conductor led to experiments that made the first refractory oxide solids containing mass independently fractionated oxygen isotopes and to 1998 predictions of the oxygen isotopic composition of the sun that were confirmed by the analysis of Genesis samples in 2011. We describe a calibration experiment that unexpectedly produced single magnetic domain iron particles. We discuss how tracking down a persistent source of "contamination" in experiments intended to produce amorphous iron and magnesium silicate smokes led to a series of studies on the synthesis of carbonaceous grain coatings that turn out to be very efficient Fischer-Tropsch catalysts and have great potential for trapping the planetary noble gases found in meteorites. We describe how models predicting the instability of silicate grains in circumstellar environments spurred new measurements of the vapor pressure of SiO partially based on previous experiments showing unexpected but systematic non-equilibrium behavior instead of the anticipated equilibrium products resembling meteoritic minerals. We trace the process that led from observations of the presence of crystalline minerals detected in the comae of some comets to the 1999 prediction of large-scale circulation of materials from the hot, innermost regions of the solar nebula out to the cold dark nebular environments where comets form. This large-scale circulation was ultimately confirmed by analyses of highly refractory Stardust samples collected from the Kuiper Belt Comet Wild 2. Finally we discuss a modern and still unresolved conflict between the assumptions built into three well known processes: the CO Self Shielding Model for mass independent isotopic fractionation of oxygen in solar system solids, rapid and thorough mixing within the solar nebula, and the efficient conversion of CO into organic coatings and volatiles on the surfaces of nebular grains via Fischer-Tropsch-type processes.

Maps of Structured Aerosol Activity During the MY 25 Planet-encircling Dust Storm on Mars

NASA Astrophysics Data System (ADS)

Noble, J.; Wilson, R. J.; Cantor, B. A.; Kahre, M. A.; Hollingsworth, J. L.; Bridger, A. F. C.; Haberle, R. M.; Barnes, J.

2016-12-01

We have produced a sequence of 42 global maps from Ls=165.1-187.7° that delimit the areal extent of structured aerosol activity based on a synthesis of Mars Global Surveyor (MGS) data, including Mars Orbiter Camera (MOC) daily global maps (DGMs) and wide angle imagery, Thermal Emission Spectrometer (TES) dust and H2O ice opacity, and Mars general circulation model (MGCM) derived dust opacity. The primary motivation of this work is to examine the temporal and spatial relationship between dust storms observed by MOC and baroclinic eddies inferred from Fast Fourier Synoptic Mapping (FFSM) of TES temperatures in order to study the initiation and evolution of Mars year (MY) 25 planet-encircling dust storm (PDS) precursor phase dust storms. A secondary motivation is to provide improved input to MGCM simulations. Assuming that structured dust storms indicate active dust lifting, these maps allow us to define potential dust lifting regions. This work has two implications for martian atmospheric science. First, integration of MGS data has enabled us to develop improved quantitative and qualitative descriptions of storm evolution that may be used to constrain estimates of dust lifting regions, horizontal dust distribution, and to infer associated circulations. Second, we believe that these maps provide better bases and constraints for modeling storm initiation. Based on our analysis of these MGS data, we propose the following working hypothesis to explain the dynamical processes responsible for PDS initiation and expansion. Six eastward-traveling transient baroclinic eddies triggered the MY 25 precursor storms in Hellas during Ls=176.2-184.6° due to the enhanced dust lifting associated with their low-level wind and stress fields. This was followed by a seventh eddy that contributed to expansion on Ls=186.3°. Increased opacity and temperatures from dust lifting associated with the first three eddies enhanced thermal tides which supported further storm initiation and expansion out of Hellas. Constructive interference of eddies and other circulation components including sublimation flow, anabatic winds (daytime upslope), and diurnal tides may have contributed to storm onset in, and expansion out of Hellas.

Atmospheric circulation classification comparison based on wildfires in Portugal

NASA Astrophysics Data System (ADS)

Pereira, M. G.; Trigo, R. M.

2009-04-01

Atmospheric circulation classifications are not a simple description of atmospheric states but a tool to understand and interpret the atmospheric processes and to model the relation between atmospheric circulation and surface climate and other related variables (Radan Huth et al., 2008). Classifications were initially developed with weather forecasting purposes, however with the progress in computer processing capability, new and more robust objective methods were developed and applied to large datasets prompting atmospheric circulation classification methods to one of the most important fields in synoptic and statistical climatology. Classification studies have been extensively used in climate change studies (e.g. reconstructed past climates, recent observed changes and future climates), in bioclimatological research (e.g. relating human mortality to climatic factors) and in a wide variety of synoptic climatological applications (e.g. comparison between datasets, air pollution, snow avalanches, wine quality, fish captures and forest fires). Likewise, atmospheric circulation classifications are important for the study of the role of weather in wildfire occurrence in Portugal because the daily synoptic variability is the most important driver of local weather conditions (Pereira et al., 2005). In particular, the objective classification scheme developed by Trigo and DaCamara (2000) to classify the atmospheric circulation affecting Portugal have proved to be quite useful in discriminating the occurrence and development of wildfires as well as the distribution over Portugal of surface climatic variables with impact in wildfire activity such as maximum and minimum temperature and precipitation. This work aims to present: (i) an overview the existing circulation classification for the Iberian Peninsula, and (ii) the results of a comparison study between these atmospheric circulation classifications based on its relation with wildfires and relevant meteorological variables. To achieve these objectives we consider the main classifications for Iberia developed within the framework of COST action 733 (Radan Huth et al., 2008). This European project aims to provide a wide range of atmospheric circulation classifications for Europe and sub-regions (http://www.cost733.org/) with an ambitious objective of assessing, comparing and classifying all relevant weather situations in Europe. Pereira et al. (2005) "Synoptic patterns associated with large summer forest fires in Portugal". Agricultural and Forest Meteorology,129, 11-25. Radan Huth et al. (2008) "Classifications of Atmospheric circulation patterns. Recent advances and applications". Trends and Directions in Climate Research: Ann. N.Y. Acad. Sci. 1146: 105-152. doi: 10.1196/annals.1446.019. Trigo R.M., DaCamara C. (2000) "Circulation Weather Types and their impact on the precipitation regime in Portugal". Int J of Climatology, 20, 1559-1581.

Laboratory Layered Latte

NASA Astrophysics Data System (ADS)

Xue, Nan; Khodaparast, Sepideh; Zhu, Lailai; Nunes, Janine; Kim, Hyoungsoo; Stone, Howard

2017-11-01

Layered composite fluids are sometimes observed in confined systems of rather chaotic initial states, for example, layered lattes formed by pouring espresso into a glass of warm milk. In such configurations, pouring forces a lower density liquid (espresso) into a higher density ambient, which is similar to the fountain effects that characterize a wide range of flows driven by injecting a fluid into a second miscible phase. Although the initial state of the mixture is complex and chaotic, there are conditions where the mixture cools at room temperature and exhibits an organized layered pattern. Here we report controlled experiments injecting a fluid into a miscible phase and show that, above a critical injection velocity, layering naturally emerges over the time scale of minutes. We perform experimental and numerical analyses of the time-dependent flows to observe and understand the convective circulation in the layers. We identify critical conditions to produce the layering and relate the results quantitatively to the critical Rayleigh number in double-diffusive convection, which indicates the competition between the horizontal thermal gradient and the vertical density gradient generated by the fluid injection. Based on this understanding, we show how to employ this single-step process to produce layered structures in soft materials, where the local elastic properties as well as the local material concentration vary step-wise along the length of the material.

Circulating Mesenchymal Stem Cells Microparticles in Patients with Cerebrovascular Disease

PubMed Central

Cho, Yeon Hee; Kang, Ho Young; Hyung, Na Kyum; Kim, Donghee; Lee, Ji Hyun; Nam, Ji Yoon; Bang, Oh Young

2012-01-01

Preclinical and clinical studies have shown that the application of CD105+ mesenchymal stem cells (MSCs) is feasible and may lead to recovery after stroke. In addition, circulating microparticles are reportedly functional in various disease conditions. We tested the levels of circulating CD105+ microparticles in patients with acute ischemic stroke. The expression of CD105 (a surface marker of MSCs) and CXCR4 (a CXC chemokine receptor for MSC homing) on circulating microparticles was evaluated by flow cytometry of samples from 111 patients and 50 healthy subjects. The percentage of apoptotic CD105 microparticles was determined based on annexin V (AV) expression. The relationship between serum levels of CD105+/AV− microparticles, stromal cells derived factor-1α (SDF-1α), and the extensiveness of cerebral infarcts was also evaluated. CD105+/AV− microparticles were higher in stroke patients than control subjects. Correlation analysis showed that the levels of CD105+/AV− microparticles increased as the baseline stroke severity increased. Multivariate testing showed that the initial severity of stroke was independently associated with circulating CD105+/AV− microparticles (OR, 1.103 for 1 point increase in the NIHSS score on admission; 95% CI, 1.032–1.178) after adjusting for other variables. The levels of CD105+/CXCR4+/AV− microparticles were also increased in patients with severe disability (r = 0.192, p = 0.046 for NIHSS score on admission), but were decreased with time after stroke onset (r = −0.204, p = 0.036). Risk factor profiles were not associated with the levels of circulating microparticles or SDF-1α. In conclusion, our data showed that stroke triggers the mobilization of MSC-derived microparticles, especially in patients with extensive ischemic stroke. PMID:22615882

Cell–specific Variation in E-selectin Ligand Expression Among Human Peripheral Blood Mononuclear Cells: Implications for Immunosurveillance and Pathobiology

PubMed Central

Silva, Mariana; Fung, Ronald Kam Fai; Donnelly, Conor Brian; Videira, Paula Alexandra; Sackstein, Robert

2017-01-01

Both host defense and immunopathology are shaped by the ordered recruitment of circulating leukocytes to affected sites, a process initiated by binding of blood-borne cells to E-selectin displayed at target endothelial beds. Accordingly, knowledge of the expression and function of leukocyte E-selectin ligands is key to understanding the tempo and specificity of immunoreactivity. Here, we performed E-selectin adherence assays under hemodynamic flow conditions coupled with flow cytometry and western blot analysis to elucidate the function and structural biology of glycoprotein E-selectin ligands expressed on human peripheral blood mononuclear cells (PBMCs). Circulating monocytes uniformly express high levels of the canonical E-selectin binding determinant sLeX and display markedly greater adhesive interactions with E-selectin than do circulating lymphocytes, which exhibit variable E-selectin binding among CD4+ and CD8+ T-cells but no binding by B-cells. Monocytes prominently present sLeX decorations on an array of protein scaffolds including PSGL-1, CD43, and CD44 (rendering the E-selectin ligands CLA, CD43E, and HCELL, respectively), and B-cells altogether lack E-selectin ligands. Quantitative PCR gene expression studies of glycosyltransferases that regulate display of sLeX reveal high transcript levels among circulating monocytes and low levels among circulating B-cells, and, commensurately, cell surface α(1,3)-fucosylation reveals that acceptor sialyllactosaminyl glycans convertible into sLeX are abundantly expressed on human monocytes yet are relatively deficient on B-cells. Collectively, these findings unveil distinct cell-specific patterns of E-selectin ligand expression among human PBMCs, indicating that circulating monocytes are specialized to engage E-selectin and providing key insights into the molecular effectors mediating recruitment of these cells at inflammatory sites. PMID:28330896

General Anesthesia Inhibits the Activity of the “Glymphatic System”

PubMed Central

Gakuba, Clement; Gaberel, Thomas; Goursaud, Suzanne; Bourges, Jennifer; Di Palma, Camille; Quenault, Aurélien; Martinez de Lizarrondo, Sara; Vivien, Denis; Gauberti, Maxime

2018-01-01

INTRODUCTION: According to the “glymphatic system” hypothesis, brain waste clearance is mediated by a continuous replacement of the interstitial milieu by a bulk flow of cerebrospinal fluid (CSF). Previous reports suggested that this cerebral CSF circulation is only active during general anesthesia or sleep, an effect mediated by the dilatation of the extracellular space. Given the controversies regarding the plausibility of this phenomenon and the limitations of currently available methods to image the glymphatic system, we developed original whole-brain in vivo imaging methods to investigate the effects of general anesthesia on the brain CSF circulation. METHODS: We used magnetic resonance imaging (MRI) and near-infrared fluorescence imaging (NIRF) after injection of a paramagnetic contrast agent or a fluorescent dye in the cisterna magna, in order to investigate the impact of general anesthesia (isoflurane, ketamine or ketamine/xylazine) on the intracranial CSF circulation in mice. RESULTS: In vivo imaging allowed us to image CSF flow in awake and anesthetized mice and confirmed the existence of a brain-wide CSF circulation. Contrary to what was initially thought, we demonstrated that the parenchymal CSF circulation is mainly active during wakefulness and significantly impaired during general anesthesia. This effect was especially significant when high doses of anesthetic agent were used (3% isoflurane). These results were consistent across the different anesthesia regimens and imaging modalities. Moreover, we failed to detect a significant change in the brain extracellular water volume using diffusion weighted imaging in awake and anesthetized mice. CONCLUSION: The parenchymal diffusion of small molecular weight compounds from the CSF is active during wakefulness. General anesthesia has a negative impact on the intracranial CSF circulation, especially when using a high dose of anesthetic agent. PMID:29344300

General Anesthesia Inhibits the Activity of the "Glymphatic System".

PubMed

Gakuba, Clement; Gaberel, Thomas; Goursaud, Suzanne; Bourges, Jennifer; Di Palma, Camille; Quenault, Aurélien; de Lizarrondo, Sara Martinez; Vivien, Denis; Gauberti, Maxime

2018-01-01

INTRODUCTION: According to the "glymphatic system" hypothesis, brain waste clearance is mediated by a continuous replacement of the interstitial milieu by a bulk flow of cerebrospinal fluid (CSF). Previous reports suggested that this cerebral CSF circulation is only active during general anesthesia or sleep, an effect mediated by the dilatation of the extracellular space. Given the controversies regarding the plausibility of this phenomenon and the limitations of currently available methods to image the glymphatic system, we developed original whole-brain in vivo imaging methods to investigate the effects of general anesthesia on the brain CSF circulation. METHODS: We used magnetic resonance imaging (MRI) and near-infrared fluorescence imaging (NIRF) after injection of a paramagnetic contrast agent or a fluorescent dye in the cisterna magna, in order to investigate the impact of general anesthesia (isoflurane, ketamine or ketamine/xylazine) on the intracranial CSF circulation in mice. RESULTS: In vivo imaging allowed us to image CSF flow in awake and anesthetized mice and confirmed the existence of a brain-wide CSF circulation. Contrary to what was initially thought, we demonstrated that the parenchymal CSF circulation is mainly active during wakefulness and significantly impaired during general anesthesia. This effect was especially significant when high doses of anesthetic agent were used (3% isoflurane). These results were consistent across the different anesthesia regimens and imaging modalities. Moreover, we failed to detect a significant change in the brain extracellular water volume using diffusion weighted imaging in awake and anesthetized mice. CONCLUSION: The parenchymal diffusion of small molecular weight compounds from the CSF is active during wakefulness. General anesthesia has a negative impact on the intracranial CSF circulation, especially when using a high dose of anesthetic agent.

Surface water subduction during a downwelling event in a semienclosed bay

NASA Astrophysics Data System (ADS)

Barton, E. D.; Torres, R.; Figueiras, F. G.; Gilcoto, M.; Largier, J.

2016-09-01

The Ría de Vigo is a bay strongly influenced by upwelling-downwelling cycles along the adjacent coast of NW Iberia. Moored and ship-board observations during September 2006 showed that subduction, initially associated with an estuarine circulation, strengthened when a strong downwelling circulation, resulting from northward wind over the coastal ocean, was generated in the outer Ría causing ambient waters to be advected outward in the lower layer. Incoming surface waters confined the estuarine circulation to the shallow interior and displaced isopleths downward through the water column at ˜10 m d-1. As the estuarine circulation retreated inward, strong flow convergence developed between middle and inner ria in the layer above 15 m, while divergence developed beneath. The convergence increased through the period of downwelling-favorable wind at a rate consistent with the observed isopleth displacement velocities. The coefficient of turbulent diffusion Kt, from a microstructure profiler, indicated that mixing was strong in the estuarine circulation and subsequently in the downwelling zone, where localized instabilities and temperature-salinity inversions were observed. During the downwelling, concentrations of phytoplankton, including potentially harmful species, increased, especially in the middle and inner ria, as a result of inward advection, subduction, and the ability of the dinoflagellates to maintain their position in the water column by swimming. In the course of the 5 day event, the water mass of all but the innermost Ría was flushed completely and replaced by waters originating in the coastally trapped poleward flow along the Atlantic coastline.

A new multi-proxy reconstruction of Atlantic deep ocean circulation during the warm mid-Pliocene

NASA Astrophysics Data System (ADS)

Riesselman, C. R.; Dowsett, H. J.; Scher, H. D.; Robinson, M. M.

2011-12-01

The mid-Pliocene (3.264 - 3.025 Ma) is the most recent interval in Earth's history with sustained global temperatures in the range of warming predicted for the 21st century, providing an appealing analog with which to examine the Earth system changes we might encounter in the coming century. Ongoing sea surface and deep ocean temperature reconstructions and coupled ocean-atmosphere general circulation model simulations by the USGS PRISM (Pliocene Research Interpretation and Synoptic Mapping) Group identify a dramatic North Atlantic warm anomaly coupled with increased evaporation in the mid-Pliocene, possibly driving enhanced meridional overturning circulation and North Atlantic Deep Water production. However deep ocean temperature is not a conclusive proxy for water mass, and most coupled model simulations predict transient decreases in North Atlantic Deep Water production in 21st century, presenting a contrasting picture of future warmer worlds. Here, we present early results from a new multi-proxy reconstruction of Atlantic deep ocean circulation during the warm mid-Pliocene, using δ13C of benthic foraminifera as a proxy for water mass age and the neodymium isotopic imprint on fossil fish teeth as a proxy for water mass source region along a three-site depth transect from the Walvis Ridge (subtropical South Atlantic). The deep ocean circulation reconstructions resulting from this project will add a new dimension to the PRISM effort and will be useful for both initialization and evaluation of future model simulations.

Revascularization for critical limb ischemia using the SpiderFX embolic protection device in the below-the-knee circulation: initial results.

PubMed

Ward, Thomas J; Piechowiak, Rachel L; Patel, Rahul S; Fischman, Aaron M; Nowakowski, F Scott; Kim, Edward; Ellozy, Sharif H; Faries, Peter L; Lookstein, Robert A

2014-10-01

To examine the safety and efficacy of the SpiderFX embolic protection device (EPD) in the below-the-knee (BTK) circulation in patients with critical limb ischemia (CLI). A single-center retrospective review was performed to identify patients with CLI and single-vessel runoff in whom the SpiderFX EPD was used in the BTK circulation. Technical success and device-related complications were the primary endpoints. Retrieval of macroscopic debris in the EPD, 1-year freedom from major adverse limb events (MALEs), and 30-day perioperative death were also evaluated. A major amputation, surgical bypass, endovascular thrombectomy, or endovascular thrombolysis was considered a MALE. Thirty-six patients (21 men; mean age, 75.8 y) treated between 2008 and 2013 had endovascular revascularization with use of the SpiderFX EPD in the BTK circulation. The SpiderFX EPD was successfully deployed in all cases; the technical success rate of revascularization was 100%. Two minor and zero major complications were observed related to the SpiderFX. Two MALEs, a major amputation and a subsequent surgical bypass, were observed in the cohort. All MALEs occurred within 1 year of treatment (1-y freedom from MALE rate, 90%). Debris was retrieved in the SpiderFX device in 47% of patients. The use of the SpiderFX EPD in the BTK circulation in patients with CLI is safe and frequently retrieves debris. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

Multifractal analysis of macro- and microcerebral circulation in rats

NASA Astrophysics Data System (ADS)

Pavlov, Alexey N.; Sindeeva, Olga S.; Sindeev, Sergey S.; Pavlova, Olga N.; Abdurashitov, Arkady S.; Rybalova, Elena V.; Semyachkina-Glushkovskaya, Oxana V.

2016-04-01

Application of noninvasive optical coherent-domain methods and advanced data processing tools such as the wavelet-based multifractal formalism allows revealing effective markers of early stages of functional distortions in the dynamics of cerebral vessels. Based on experiments performed in rats we discuss a possibility to diagnose a hidden stage of the development of intracranial hemorrhage (ICH). We also consider responses of the cerebrovascular dynamics to a pharmacologically induced increase in the peripheral blood pressure. We report distinctions occurring at the levels of macro- and microcerebral circulation.

Seasonal changes in the atmospheric heat balance simulated by the GISS general circulation model

NASA Technical Reports Server (NTRS)

Stone, P. H.; Chow, S.; Helfand, H. M.; Quirk, W. J.; Somerville, R. C. J.

1975-01-01

Tests of the ability of numerical general circulation models to simulate the atmosphere have focussed so far on simulations of the January climatology. These models generally present boundary conditions such as sea surface temperature, but this does not prevent testing their ability to simulate seasonal changes in atmospheric processes that accompany presented seasonal changes in boundary conditions. Experiments to simulate changes in the zonally averaged heat balance are discussed since many simplified models of climatic processes are based solely on this balance.

Results of the Winter Flow Experiments Conducted on December 7-8, February 7-8, and February 28-29, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dressen, Donald S.; Beikmann, Mel

A winter flow regime has been proposed as a method of maintaining a non-freezing environment following the loss of circulation in the HDR Reservoir test facility when ambient temperature is below 32 °F. The regime, as presently envisioned, would automatically convert the surface facility from reservoir circulation to low rate reservoir production through the entire operating system except the EE-3A wellhead, the EE-2A x-mas tree, and the make-up/feed pump/water supply system.

Experience with a vectorized general circulation weather model on Star-100

NASA Technical Reports Server (NTRS)

Soll, D. B.; Habra, N. R.; Russell, G. L.

1977-01-01

A version of an atmospheric general circulation model was vectorized to run on a CDC STAR 100. The numerical model was coded and run in two different vector languages, CDC and LRLTRAN. A factor of 10 speed improvement over an IBM 360/95 was realized. Efficient use of the STAR machine required some redesigning of algorithms and logic. This precludes the application of vectorizing compilers on the original scalar code to achieve the same results. Vector languages permit a more natural and efficient formulation for such numerical codes.

Ex-vivo porcine organs with a circulation pump are effective for teaching hemostatic skills

PubMed Central

2012-01-01

Surgical residents have insufficient opportunites to learn basic hemostatic skills from clinical experience alone. We designed an ex-vivo training system using porcine organs and a circulation pump to teach hemostatic skills. Residents were surveyed before and after the training and showed significant improvement in their self-confidence (1.83 ± 1.05 vs 3.33 ± 0.87, P < 0.01) on a 5 point Likert scale. This training may be effective to educate residents in basic hemostatic skills. PMID:22404974

Microbial Life Driving Low-Temperature Basalt Alteration in the Subsurface: Decoupling Abiotic Processes from Biologically-Mediated Rock Alteration

NASA Astrophysics Data System (ADS)

Moore, R.; Lecoeuvre, A.; Stephant, S.; Dupraz, S.; Ranchou-Peyruse, M.; Ranchou-Peyruse, A.; Gérard, E.; Ménez, B.

2017-12-01

Microorganisms are involved with specific rock alteration processes in the deep subsurface. It is a challenge to link any contribution microbial life may have on rock alteration with specific functions or phyla because many alteration features and secondary minerals produced by metabolic processes can also produce abiotically. Here, two flow-through experiments were designed to mimic the circulation of a CO2-rich fluid through crystalline basalt. In order to identify microbially-mediated alteration and be able to link it with specific metabolisms represented in the subsurface, a relatively fresh crystalline basalt substrate was subsampled, sterilized and used as the substrate for both experiments. In one experiment, the substrate was left sterile, and in the other it was inoculated with an enrichment culture derived from the same aquifer as the rock substrate. Initial results show that the inoculum contained Proteobacteria and Firmicutes, which have diverse metabolic potentials. Fluid and rock analyses before, during, and after the experiments show that mineralogy, fluid chemistry, and dissolution processes differ between the sterile and inoculated systems. In the inoculated experiment iron-rich orthopyroxenes were preferentially dissolved while in the sterile system clinopyroxenes and plagioclases both exhibited a higher degree of dissolution. Additionally, the patterns of CO2 consumption and production over the duration of both experiments is different. This suggest that in a low-temperature basalt system with microorganisms CO2 is either consumed to produce biomass, or that carbonates are produced and then subsequently preserved. This suite of results combined with molecular ecology analyses can be used to conclude that in low-temperature basalts microorganisms play an intrinsic role in rock alteration.

Combined Steady-State and Dynamic Heat Exchanger Experiment

ERIC Educational Resources Information Center

Luyben, William L.; Tuzla, Kemal; Bader, Paul N.

2009-01-01

This paper describes a heat-transfer experiment that combines steady-state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas…

Dynamics of the Circulation in the Sea of Marmara: Numerical Modeling Experiments and Observations from the Turkish Straits System Experiment

DTIC Science & Technology

2011-01-01

Chiggiato & Ewa Jarosz & Jeffrey W. Book & James Dykes & Lucio Torrisi & Pierre-Marie Poulain & Riccardo Gerin & Jochen Horstmann & Şükrü Beşiktepe...Rapid Environmental Assessment J. Chiggiato (*) : J. Horstmann : Ş. Beşiktepe NATO Undersea Research Centre, La Spezia, Italy e-mail: chiggiato

Bathymetric Changes Shaped by Longshore Currents on a Natural Beach

NASA Astrophysics Data System (ADS)

Reilly, W. L.; Slinn, D.; Plant, N.

2004-12-01

The goal of the project is to simulate beach morphology on time scales of hours to days. Our approach is to develop finite difference solutions from a coupled modeling system consisting of existing nearshore circulation, wave, and sediment flux models. We initialize the model with bathymetry from a dense data set north of the pier at the Field Research Facility (FRF) in Duck, NC. We integrate the model system forward in time and compare the results of the hind-cast of the beach evolution with the field observations. The model domain extends 1000 meters in the alongshore direction and 500 meters in the cross-shore direction with 5 meter grid spacing. The bathymetry is interpolated and filtered from CRAB transects. A second-degree exponential smoothing method is used to return the cross-shore beach profile near the edges of the modeled domain back to the mean alongshore profile, because the circulation model implements periodic boundary conditions in the alongshore direction. The offshore wave height and direction are taken from the 8-meter bipod at the FRF and input to the wave-model, SWAN (Spectral Wave Nearshore), with a Gaussian-shaped frequency spectrum and a directional spreading of 5 degrees. A constant depth induced wave breaking parameter of 0.73 is used. The resulting calculated wave induced force per unit surface area (gradient of the radiation stress) output from SWAN is used to drive the currents in the circulation model. The circulation model is based on the free-surface non-linear shallow water equations and uses the fourth order compact scheme to calculate spatial derivatives and a third order Adams-Bashforth time discretization scheme. Free slip, symmetry boundary conditions are applied at both the shoreline and offshore boundaries. The time averaged sediment flux is calculated at each location after one hour of circulation. The sediment flux model is based on the approach of Bagnold and includes approximations for both bed-load and suspended load. The bathymetry is then updated by computing the divergence of the time averaged sediment fluxes. The process is then repeated using the updated bathymetry in both SWAN and the circulation model. The cycle continues for a simulation of 10 hours. The results of bathymetric change vary for different time-dependent wave conditions and initial bathymetric profiles. Typical results indicate that for wave heights on the order of one meter, shoreline advancement and sandbar evolution is observed on the order of tens of centimeters.

Customized Internal Reference Controls for Improved Assessment of Circulating MicroRNAs in Disease.

PubMed

Schlosser, Kenny; McIntyre, Lauralyn A; White, R James; Stewart, Duncan J

2015-01-01

Altered levels of circulating extracellular miRNA in plasma and serum have shown promise as non-invasive biomarkers of disease. However, unlike the assessment of cellular miRNA levels for which there are accepted housekeeping genes, analogous reference controls for normalization of circulating miRNA are lacking. Here, we provide an approach to identify and validate circulating miRNA reference controls on a de novo basis, and demonstrate the advantages of these customized internal controls in different disease settings. Importantly, these internal controls overcome key limitations of external spike-in controls. Using a global RT-qPCR screen of 1066 miRNAs in plasma from pulmonary hypertension patients (PAH) and healthy subjects as a case example, we identified a large pool of initial candidate miRNAs that were systematically ranked according to their plasma level stability using a predefined algorithm. The performance of the top candidates was validated against multiple comparators, and in a second independent cohort of PAH and control subjects. The broader utility of this approach was demonstrated in a completely different disease setting with 372 miRNAs screened in plasma from septic shock patients and healthy controls. Normalization of data with specific internal reference controls significantly reduced the overall variation in circulating miRNA levels between subjects (relative to raw data), provided a more balanced distribution of up- and down-regulated miRNAs, replicated the results obtained by the benchmark geometric averaging of all detected miRNAs, and outperformed the commonly used external spike-in strategy. We demonstrate the feasibility of identifying circulating reference controls that can reduce extraneous technical variations, and improve the assessment of disease-related changes in plasma miRNA levels. This study provides a novel conceptual framework that addresses a critical and previously unmet need if circulating miRNAs are to advance as reliable diagnostic tools in medicine.

Customized Internal Reference Controls for Improved Assessment of Circulating MicroRNAs in Disease

PubMed Central

Schlosser, Kenny; McIntyre, Lauralyn A.; White, R. James; Stewart, Duncan J.

2015-01-01

Background Altered levels of circulating extracellular miRNA in plasma and serum have shown promise as non-invasive biomarkers of disease. However, unlike the assessment of cellular miRNA levels for which there are accepted housekeeping genes, analogous reference controls for normalization of circulating miRNA are lacking. Here, we provide an approach to identify and validate circulating miRNA reference controls on a de novo basis, and demonstrate the advantages of these customized internal controls in different disease settings. Importantly, these internal controls overcome key limitations of external spike-in controls. Methods Using a global RT-qPCR screen of 1066 miRNAs in plasma from pulmonary hypertension patients (PAH) and healthy subjects as a case example, we identified a large pool of initial candidate miRNAs that were systematically ranked according to their plasma level stability using a predefined algorithm. The performance of the top candidates was validated against multiple comparators, and in a second independent cohort of PAH and control subjects. The broader utility of this approach was demonstrated in a completely different disease setting with 372 miRNAs screened in plasma from septic shock patients and healthy controls. Results Normalization of data with specific internal reference controls significantly reduced the overall variation in circulating miRNA levels between subjects (relative to raw data), provided a more balanced distribution of up- and down-regulated miRNAs, replicated the results obtained by the benchmark geometric averaging of all detected miRNAs, and outperformed the commonly used external spike-in strategy. Conclusions We demonstrate the feasibility of identifying circulating reference controls that can reduce extraneous technical variations, and improve the assessment of disease-related changes in plasma miRNA levels. This study provides a novel conceptual framework that addresses a critical and previously unmet need if circulating miRNAs are to advance as reliable diagnostic tools in medicine. PMID:26010841

Microbially mediated alteration of crystalline basalts as identified from analogical reactive percolation experiments

NASA Astrophysics Data System (ADS)

Moore, Rachael; Ménez, Bénédicte; Stéphant, Sylvian; Dupraz, Sébastien; Ranchou-Peyruse, Magali; Ranchou-Peyruse, Anthony; Gérard, Emmanuelle

2017-04-01

Alteration in the ocean crust through fluid circulation is an ongoing process affecting the first kilometers and at low temperatures some alteration may be microbially mediated. Hydrothermal activity through the hard rock basement supports diverse microbial communities within the rock by providing nutrient and energy sources. Currently, the impact of basement hosted microbial communities on alteration is poorly understood. In order to identify and quantify the nature of microbially mediated alteration two reactive percolation experiments mimicking circulation of CO2 enriched ground water were performed at 35 °C and 30 bar for 21 days each. The experiments were performed using a crystalline basalt substrate from an earlier drilled deep Icelandic aquifer. One experiment was conducted on sterile rock while the other was conducted with the addition of a microbial inoculate derived from groundwater enrichment cultures obtained from the same aquifer. µCT on the experimental basaltic substrate before and after the reactive percolation experiment along with synchrotron radiation x-ray tomographic microscopy and the mineralogical characterization of resulting material allows for the comparative volumetric quantification of dissolution and precipitation. The unique design of this experiment allows for the identification of alteration which occurs solely abiotically and of microbially mediated alteration. Experimental results are compared to natural basaltic cores from Iceland retrieved following a large field CO2 injection experiment that stimulated microbial activity at depth.

On the possibility of connecting a non-operating main circulation pump with three pumps in operation without preliminary coast-down of power-generating unit No. 5 in the Novovoronezh nuclear power plant

NASA Astrophysics Data System (ADS)

Vitkovskii, I. L.; Nikonov, S. P.; Ryasnyi, S. I.

2014-02-01

The subject of this paper is a transient caused by connection of a standby loop to three operating circulation pumps at the initial reactor heat rate equal to 70% of the rated value without preliminarily reducing it to 30% of the rated level as required by the safe operation regulations. Failure of the following normal operation systems is supposed: the first- and the second-type warning protection systems, all quick-acting reducing devices releasing steam into the auxiliary manifold, the electric heaters of the pressurizer, the pressurizer injection system, the primary cooling circuit fluid makeup/blow-through systems, and the blocking systems to shut down the main circulation pump after the level in the steam generator is exceeded. In addition, it is supposed that, under transient conditions, the valves of the turbine regulation system will be in the position in which they were at the moment of the initial event until generation of the signal for positive closing of the turbine stop valves. The first signal to actuate the reactor emergency protection system (EPS) is skipped. The failure of all quick-acting reducing devices releasing steam into the atmosphere is assumed. In addition to equipment failure, at the moment when the main circulation pump is connected, the operator erroneously puts in a new setting to maintain the power allowable for four pumps in operation-in the calculations it was taken equal to 104% of the rated level at most considering the accuracy of evaluating and maintaining the reactor heat rate-and the working group of the reactor protection and control system (P&CS) starts moving upward. On reaching the set power level, the automatic reactor power regulator stops operating and the P&CS elements remain in the position in which they are at the moment. Compliance with the design safety criteria for the adopted scenario of the transient is demonstrated.

A race-specific interaction between vitamin K status and statin use during warfarin therapy initiation

USDA-ARS?s Scientific Manuscript database

Vitamin K (VK) is required for the post-translational modification of several clotting factors. Warfarin is a vitamin K antagonist and anticoagulant. The most common dietary and circulating form of VK is phylloquinone (PK). PK is lipid soluble, carried by triglyceride-rich lipoproteins, and shares a...