Short-Term International Internship Experiences for Future Teachers and Other Child Development Professionals

ERIC Educational Resources Information Center

Miller, Kari Knutson; Gonzalez, Amber M.

2016-01-01

This paper examines outcomes associated with participation in short-term, international internship experiences. Results suggest short-term international internship experiences contribute to rich personal and professional development outcomes. Findings highlight participant challenges associated with initial internship experiences, professional…

Simulated storm surge effects on freshwater coastal wetland soil porewater salinity and extractable ammonium levels: Implications for marsh recovery after storm surge

NASA Astrophysics Data System (ADS)

McKee, M.; White, J. R.; Putnam-Duhon, L. A.

2016-11-01

Coastal wetland systems experience both short-term changes in salinity, such as those caused by wind-driven tides and storm surge, and long-term shifts caused by sea level rise. Salinity increases associated with storm surge are known to have significant effects on soil porewater chemistry, but there is little research on the effect of flooding length on salt penetration depth into coastal marsh soils. A simulated storm surge was imposed on intact soil columns collected from a non-vegetated mudflat and a vegetated marsh site in the Wax Lake Delta, LA. Triplicate intact cores were continuously exposed to a 35 salinity water column (practical salinity scale) for 1, 2, and 4 weeks and destructively sampled in order to measure porewater salinity and extractable NH4sbnd N at two cm depth intervals. Salinity was significantly higher in the top 8 cm for both the marsh and mudflat cores after one week of flooding. After four weeks of flooding, salinity was significantly higher in marsh and mudflat cores compared to the control (no salinity) cores throughout the profile for both sites. Extractable ammonium levels increased significantly in the marsh cores throughout the experiment, but there was only a marginally (p < 0.1) significant increase seen in the mudflat cores. Results indicate that porewater salinity levels can become significantly elevated within a coastal marsh soil in just one week. This vertical intrusion of salt can potentially negatively impact macrophytes and associated microbial communities for significantly longer term post-storm surge.

Mobility of multiwalled carbon nanotubes in porous media.

PubMed

Liu, Xueying; O'Carroll, Denis M; Petersen, Elijah J; Huang, Qingguo; Anderson, C Lindsay

2009-11-01

Engineered multiwalled carbon nanotubes (MWCNTs) are the subject of intense research and are expected to gain widespread usage in a broad variety of commercial products. However, concerns have been raised regarding potential environmental and human health risks. The mobility of MWCNTs in porous media is examined in this study using one-dimensional flow-through column experiments under conditions representative of subsurface and drinking water treatment systems. Results demonstrate that pore water velocity strongly influenced MWCNT transport, with high MWCNT mobility at pore water velocities greater than 4.0 m/d. A numerical simulator, which incorporated a newly developed theoretical collector efficiency relationship for MWCNTs in spherical porous media, was developed to model observed column results. The model, which incorporated traditional colloid filtration theory in conjunction with a site-blocking term, yielded good agreement with observed results in quartz sand-packed column experiments. Experiments were also conducted in glass bead-packed columns with the same mean grain size as the quartz sand-packed columns. MWCNTs were more mobile in the glass bead-packed columns.

A simple analytical infiltration model for short-duration rainfall

NASA Astrophysics Data System (ADS)

Wang, Kaiwen; Yang, Xiaohua; Liu, Xiaomang; Liu, Changming

2017-12-01

Many infiltration models have been proposed to simulate infiltration process. Different initial soil conditions and non-uniform initial water content can lead to infiltration simulation errors, especially for short-duration rainfall (SHR). Few infiltration models are specifically derived to eliminate the errors caused by the complex initial soil conditions. We present a simple analytical infiltration model for SHR infiltration simulation, i.e., Short-duration Infiltration Process model (SHIP model). The infiltration simulated by 5 models (i.e., SHIP (high) model, SHIP (middle) model, SHIP (low) model, Philip model and Parlange model) were compared based on numerical experiments and soil column experiments. In numerical experiments, SHIP (middle) and Parlange models had robust solutions for SHR infiltration simulation of 12 typical soils under different initial soil conditions. The absolute values of percent bias were less than 12% and the values of Nash and Sutcliffe efficiency were greater than 0.83. Additionally, in soil column experiments, infiltration rate fluctuated in a range because of non-uniform initial water content. SHIP (high) and SHIP (low) models can simulate an infiltration range, which successfully covered the fluctuation range of the observed infiltration rate. According to the robustness of solutions and the coverage of fluctuation range of infiltration rate, SHIP model can be integrated into hydrologic models to simulate SHR infiltration process and benefit the flood forecast.

Long-term ozone and temperature correlations above SANAE, Antarctica

NASA Technical Reports Server (NTRS)

Bodeker, Gregory E.; Scourfield, Malcolm W. J.

1994-01-01

A significant decline in Antarctic total column ozone and upper air temperatures has been observed in recent years. Furthermore, high correlations between monthly mean values of ozone and stratospheric temperature have been measured above Syowa, Antarctica. For the observations reported here, data from TOMS (Total Ozone Mapping Spectrometer) aboard the Nimbus 7 satellite have been used to examine the 1980 to 1990 decrease in total column ozone above the South African Antarctic base of SANAE (70 deg 18 min S, 2 deg 21 min W). The cooling of the Antarctic stratosphere above SANAE during this period has been investigated by examining upper air temperatures at the 150, 100, 70, 50, and 30 hPa levels obtained from daily radiosonde balloon launches. Furthermore, these two data sets have been used to examine long-term, medium-term, and short-term correlations between total column ozone and the temperatures at each of the five levels. The trend in SANAE total column ozone has been found to be -4.9 DU/year, while upper air temperatures have been found to decrease at around 0.3 C/year. An analysis of monthly average SANAE total column ozone has shown the decrease to be most severe during the month of September with a trend of -7.7 DU/year. A strong correlation (r(exp 2) = 0.92) has been found between yearly average total column ozone and temperature at the 100 hPa level. Daily ozone and temperature correlations show high values from September to November, at a time when the polar vortex is breaking down.

Predicting isoproturon long-term mineralization from short-term experiment: Can this be a suitable approach?

PubMed

Wang, Fang; Dörfler, Ulrike; Jiang, Xin; Schroll, Reiner

2016-02-01

A worldwide used pesticide - isoproturon (IPU) - was selected to test whether short-term experiments can be used to predict long-term mineralization of IPU in soil. IPU-mineralization was measured for 39 and 265 days in four different agricultural soils with a low mineralization dynamic. Additionally, in one soil IPU dissipation, formation and dissipation of metabolites, formation of non-extractable residues (NER) and (14)C-microbial biomass from (14)C-IPU were monitored for 39 and 265 days. The data from short-term and long-term experiments were used for model fitting. The long-term dynamics of IPU mineralization were considerably overestimated by the short-term experiments in two soils with neutral pH, while in two other soils with low pH and lower mineralization, the long-term mineralization of IPU could be sufficiently predicted. Additional investigations in one of the soils with neutral pH showed that dissipation of IPU and metabolites could be correctly predicted by the short-term experiment. However, the formation of NER and (14)C-microbial biomass were remarkably overestimated by the short-term experiment. Further, it could be shown that the released NER and (14)C-microbial biomass were the main contributors of (14)CO2 formation at later incubation stages. Taken together, our results indicate that in soils with neutral pH short-term experiments were inadequate to predict the long-term mineralization of IPU. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reliability assessment of slender concrete columns at the stability failure

NASA Astrophysics Data System (ADS)

Valašík, Adrián; Benko, Vladimír; Strauss, Alfred; Täubling, Benjamin

2018-01-01

The European Standard for designing concrete columns within the use of non-linear methods shows deficiencies in terms of global reliability, in case that the concrete columns fail by the loss of stability. The buckling failure is a brittle failure which occurs without warning and the probability of its formation depends on the columns slenderness. Experiments with slender concrete columns were carried out in cooperation with STRABAG Bratislava LTD in Central Laboratory of Faculty of Civil Engineering SUT in Bratislava. The following article aims to compare the global reliability of slender concrete columns with slenderness of 90 and higher. The columns were designed according to methods offered by EN 1992-1-1 [1]. The mentioned experiments were used as basis for deterministic nonlinear modelling of the columns and subsequent the probabilistic evaluation of structural response variability. Final results may be utilized as thresholds for loading of produced structural elements and they aim to present probabilistic design as less conservative compared to classic partial safety factor based design and alternative ECOV method.

Bearing capacity and rigidity of short plastic-concrete-tubal vertical columns under transverse load

NASA Astrophysics Data System (ADS)

Dolzhenko, A. V.; Naumov, A. E.; Shevchenko, A. E.

2018-03-01

The results of mathematical modeling in determining strain-stress distribution parameters of a short plastic-concrete-tubal vertical column under horizontal load as those in vertical constructions are described. Quantitative parameters of strain-stress distribution during vertical and horizontal loads and horizontal stiffness were determined by finite element modeling. The internal stress in the concrete column core was analyzed according to equivalent stress in Mohr theory of failure. It was determined that the bearing capacity of a short plastic- concrete-tubal vertical column is 25% higher in resistibility and 15% higher in rigidness than those of the caseless concrete columns equal in size. Cracks formation in the core of a short plastic-concrete-tubal vertical column happens under significantly bigger horizontal loads with less amount of concrete spent than that in caseless concrete columns. The significant increase of bearing capacity and cracking resistance of a short plastic-concrete-tubal vertical column under vertical and horizontal loads allows recommending them as highly effective and highly reliable structural wall elements in civil engineering.

Heavy metal leaching from mine tailings as affected by plants

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

Zhu, D.; Schwab, A.P.; Banks, M.K.

A column experiment was conducted to determine the impact of soil cover and plants on heavy metal leaching from mine tailings and heavy metal contaminated soil. Columns made of PVC were constructed with 30 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm of clean topsoil. Two grasses, tall fescue (Festuca arundinacea Schreb.) and big bluestem (Andropogon gerardii), were grown in the columns. The columns were leached at a slow rate for 1 yr with a 0.001 Mmore » CaCl{sub 2} solution under unsaturated conditions. The presence of both tall fescue and big bluestem increased Zn and Cd concentrations in the leachate. Lead concentrations in leachates were not affected by the presence of plants. Although plants generally reduced the total amount of water leached, total mass of Zn and Cd leached generally was not impacted by plants. Total mass of Pb leached was positively correlated with total leachate collected from each column. Covering the mine tailings with 60 cm of topsoil increased the mass of Zn and Cd leached relative to no topsoil. When the subsoil was absent, Zn and Cd leaching increased by as much as 20-fold, verifying the ability of soil to act as a sink for metals. Mine tailing remediation by establishing vegetation can reduce Pb movement but may enhance short-term Cd and Zn leaching. However, the changes were relatively small and do not outweigh the benefits of using vegetation in mine tailings reclamation.« less

The effect of feed water dissolved organic carbon concentration and composition on organic micropollutant removal and microbial diversity in soil columns simulating river bank filtration.

PubMed

Bertelkamp, C; van der Hoek, J P; Schoutteten, K; Hulpiau, L; Vanhaecke, L; Vanden Bussche, J; Cabo, A J; Callewaert, C; Boon, N; Löwenberg, J; Singhal, N; Verliefde, A R D

2016-02-01

This study investigated organic micropollutant (OMP) biodegradation rates in laboratory-scale soil columns simulating river bank filtration (RBF) processes. The dosed OMP mixture consisted of 11 pharmaceuticals, 6 herbicides, 2 insecticides and 1 solvent. Columns were filled with soil from a RBF site and were fed with four different organic carbon fractions (hydrophilic, hydrophobic, transphilic and river water organic matter (RWOM)). Additionally, the effect of a short-term OMP/dissolved organic carbon (DOC) shock-load (e.g. quadrupling the OMP concentrations and doubling the DOC concentration) on OMP biodegradation rates was investigated to assess the resilience of RBF systems. The results obtained in this study imply that - in contrast to what is observed for managed aquifer recharge systems operating on wastewater effluent - OMP biodegradation rates are not affected by the type of organic carbon fraction fed to the soil column, in case of stable operation. No effect of a short-term DOC shock-load on OMP biodegradation rates between the different organic carbon fractions was observed. This means that the RBF site simulated in this study is resilient towards transient higher DOC concentrations in the river water. However, a temporary OMP shock-load affected OMP biodegradation rates observed for the columns fed with the river water organic matter (RWOM) and the hydrophilic fraction of the river water organic matter. These different biodegradation rates did not correlate with any of the parameters investigated in this study (cellular adenosine triphosphate (cATP), DOC removal, specific ultraviolet absorbance (SUVA), richness/evenness of the soil microbial population or OMP category (hydrophobicity/charge). Copyright © 2015 Elsevier Ltd. All rights reserved.

Assessing the associative deficit of older adults in long-term and short-term/working memory.

PubMed

Chen, Tina; Naveh-Benjamin, Moshe

2012-09-01

Older adults exhibit a deficit in associative long-term memory relative to younger adults. However, the literature is inconclusive regarding whether this deficit is attenuated in short-term/working memory. To elucidate the issue, three experiments assessed younger and older adults' item and interitem associative memory and the effects of several variables that might potentially contribute to the inconsistent pattern of results in previous studies. In Experiment 1, participants were tested on item and associative recognition memory with both long-term and short-term retention intervals in a single, continuous recognition paradigm. There was an associative deficit for older adults in the short-term and long-term intervals. Using only short-term intervals, Experiment 2 utilized mixed and blocked test designs to examine the effect of test event salience. Blocking the test did not attenuate the age-related associative deficit seen in the mixed test blocks. Finally, an age-related associative deficit was found in Experiment 3, under both sequential and simultaneous presentation conditions. Even while accounting for some methodological issues, the associative deficit of older adults is evident in short-term/working memory.

Long-term Kinetics of Uranyl Desorption from Sediments Under Advective Conditions

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

Shang, Jianying; Liu, Chongxuan; Wang, Zheming

2014-02-15

Long-term (> 4 months) column experiments were performed to investigate the kinetics of uranyl (U(VI)) desorption in sediments collected from the Integrated Field Research Challenge (IFRC) site at the US Department of Energy (DOE) Hanford 300 Area. The experimental results were used to evaluate alternative multi-rate surface complexation reaction (SCR) approaches to describe the short- and long-term kinetics of U(VI) desorption under flow conditions. The SCR stoichiometry, equilibrium constants, and multi-rate parameters were independently characterized in batch and stirred flow-cell reactors. Multi-rate SCR models that were either additively constructed using the SCRs for individual size fractions (e.g., Shang et al.,more » 2011), or composite in nature could effectively describe short-term U(VI) desorption under flow conditions. The long-term desorption results, however, revealed that using a labile U concentration measured by carbonate extraction under-estimated desorbable U(VI) and the long-term rate of U(VI) desorption. An alternative modeling approach using total U as the desorbable U(VI) concentration was proposed to overcome this difficulty. This study also found that the gravel size fraction (2-8 mm), which is typically treated as non-reactive in modeling U(VI) reactive transport because of low external surface area, can have an important effect on the U(VI) desorption in the sediment. This study demonstrates an approach to effectively extrapolate U(VI) desorption kinetics for field-scale application, and identifies important parameters and uncertainties affecting model predictions.« less

75 FR 55579 - Proposed Agency Information Collection Activities; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-13

... balance sheet data on major categories of consumer and business credit receivables and on major short-term... items are collected to provide a full balance sheet. A supplemental section collects data on securitized... two columns to create a clearer distinction among broad balance sheet data items, which are collected...

The Watts New? Collection: Columns by the SEI’s Watts Humphrey

DTIC Science & Technology

2009-11-01

included with all reproductions and derivative works. External use. This document may be reproduced in its entirety, without modification, and freely...all of the buzzwords, would like to act strategically, and talks about being the industry leader, managers are hypnotized by their short-term problems

Hydrologic control on redox and nitrogen dynamics in a peatland soil.

PubMed

Rubol, Simonetta; Silver, Whendee L; Bellin, Alberto

2012-08-15

Soils are a dominant source of nitrous oxide (N(2)O), a potent greenhouse gas. However, the complexity of the drivers of N(2)O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N(2)O fluxes. Soil moisture can be considered a key driver because it influences oxygen (O(2)) supply, which feeds back on N(2)O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil water content is directly linked to O(2) and redox potential, which regulate microbial metabolism and chemical transformations in the environment. Despite its importance, only a few laboratory studies have addressed the effects of hydrological transient dynamics on nitrogen (N) cycling in the vadose zone. To further investigate these aspects, we performed a long term experiment in a 1.5 m depth soil column supplemented by chamber experiments. With this experiment, we aimed to investigate how soil moisture dynamics influence redox sensitive N cycling in a peatland soil. As expected, increased soil moisture lowered O(2) concentrations and redox potential in the soil. The decline was more severe for prolonged saturated conditions than for short events and at deep than at the soil surface. Gaseous and dissolved N(2)O, dissolved nitrate (NO(3)(-)) and ammonium (NH(4)(+)) changed considerably along the soil column profile following trends in soil O(2) and redox potential. Hot spots of N(2)O concentrations corresponded to high variability in soil O(2) in the upper and lower parts of the column. Results from chamber experiments confirmed high NO(3)(-) reduction potential in soils, particularly from the bottom of the column. Under our experimental conditions, we identified a close coupling of soil O(2) and N(2)O dynamics, both of which lagged behind soil moisture changes. These results highlight the relationship among soil hydrologic properties, redox potential and N cycling, and suggest that models working at a daily scale need to consider soil O(2) dynamics in addition to soil moisture dynamics to accurately predict patterns in N(2)O fluxes. Copyright © 2012 Elsevier B.V. All rights reserved.

One-dimensional model of inertial pumping

NASA Astrophysics Data System (ADS)

Kornilovitch, Pavel E.; Govyadinov, Alexander N.; Markel, David P.; Torniainen, Erik D.

2013-02-01

A one-dimensional model of inertial pumping is introduced and solved. The pump is driven by a high-pressure vapor bubble generated by a microheater positioned asymmetrically in a microchannel. The bubble is approximated as a short-term impulse delivered to the two fluidic columns inside the channel. Fluid dynamics is described by a Newton-like equation with a variable mass, but without the mass derivative term. Because of smaller inertia, the short column refills the channel faster and accumulates a larger mechanical momentum. After bubble collapse the total fluid momentum is nonzero, resulting in a net flow. Two different versions of the model are analyzed in detail, analytically and numerically. In the symmetrical model, the pressure at the channel-reservoir connection plane is assumed constant, whereas in the asymmetrical model it is reduced by a Bernoulli term. For low and intermediate vapor bubble pressures, both models predict the existence of an optimal microheater location. The predicted net flow in the asymmetrical model is smaller by a factor of about 2. For unphysically large vapor pressures, the asymmetrical model predicts saturation of the effect, while in the symmetrical model net flow increases indefinitely. Pumping is reduced by nonzero viscosity, but to a different degree depending on the microheater location.

One-dimensional model of inertial pumping.

PubMed

Kornilovitch, Pavel E; Govyadinov, Alexander N; Markel, David P; Torniainen, Erik D

2013-02-01

A one-dimensional model of inertial pumping is introduced and solved. The pump is driven by a high-pressure vapor bubble generated by a microheater positioned asymmetrically in a microchannel. The bubble is approximated as a short-term impulse delivered to the two fluidic columns inside the channel. Fluid dynamics is described by a Newton-like equation with a variable mass, but without the mass derivative term. Because of smaller inertia, the short column refills the channel faster and accumulates a larger mechanical momentum. After bubble collapse the total fluid momentum is nonzero, resulting in a net flow. Two different versions of the model are analyzed in detail, analytically and numerically. In the symmetrical model, the pressure at the channel-reservoir connection plane is assumed constant, whereas in the asymmetrical model it is reduced by a Bernoulli term. For low and intermediate vapor bubble pressures, both models predict the existence of an optimal microheater location. The predicted net flow in the asymmetrical model is smaller by a factor of about 2. For unphysically large vapor pressures, the asymmetrical model predicts saturation of the effect, while in the symmetrical model net flow increases indefinitely. Pumping is reduced by nonzero viscosity, but to a different degree depending on the microheater location.

Change in Measured Noncognitive Variables: A Quantitative Examination of the Influence of Short-Term Study Abroad Experiences

ERIC Educational Resources Information Center

Motley, Reginald James

2013-01-01

Students have different motivations for participating in education abroad experiences. Short-term study abroad programs offer students the opportunity to experience education abroad without spending an entire semester or year abroad. As a result of these opportunities, short-term study abroad programs have emerged to meet the demands for students…

Removal of Sb-125 and Tc-99 from Liquid Radwaste by Novel Adsorbents

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

Harjula, R.O.; Koivula, R.; Paajanen, A.

2006-07-01

Novel proprietary metal oxide materials (MOM) have been tested for the removal of Sb-125 from simulated Floor Drain Waters of BWR. Antimony was present in the solutions as oxidized anionic form. Long term column experiment with simulated liquid that showed high Sb-125 removal at least up to 8000 bed volumes. One column experiments was carried out using nonradioactive Sb to exhaust the column. Leaching tests with 1000 ppm boric acid showed that 100 % of absorbed Sb remains in the sorbent material. Column experiments with real Fuel Pond Water from Olkiluoto NPP (BWR) showed reduction of Sb-125 (feed level 400more » Bq/L, 1.10{sup -5} {mu}Ci/mL) below detection limit (MDA = 1.7 Bq/L, 5.10{sup -8},{mu}Ci/mL). Additional experiments have also been carried out with pertechnetate (Tc-99) ions. Results indicate that MOM materials are efficient also for the removal of Tc-99 from concentrated NaNO{sub 3} solution. (authors)« less

LABORATORY INVESTIGATION OF RESIDUAL LIQUID ORGANICS FROM SPILLS, LEAKS, AND THE DISPOSAL OF HAZARDOUS WASTES IN GROUNDWATER

EPA Science Inventory

Organic liquids that are essentially immiscible with water migrate through the subsurface through the influence of capillary, viscous and buoyancy forces. our experimental methods were employed. irst, quantitative displacement experiments using short soil columns; second, additio...

LABORATORY INVESTIGATION OF RESIDUAL LIQUID ORGANICS FROM SPILLS, LEAKS, AND THE DISPOSAL OF HAZARDOUS WASTES IN GROUNDWATER

EPA Science Inventory

Organic liquids that are essentially immiscible with water migrate through the subsurface through the influence of capillary, viscous and buoyancy forces. Four experimental methods were employed. First, quantitative displacement experiments using short soil columns; second, add...

A paradigm shift in the surgical reconstruction of extra-articular distal humeral fractures: single-column plating.

PubMed

Meloy, Gregory M; Mormino, Matthew A; Siska, Peter A; Tarkin, Ivan S

2013-11-01

The study aimed (1) to examine if there are equivalent results in terms of union, alignment and elbow functionally comparing single- to dual-column plating of AO/OTA 13A2 and A3 distal humeral fractures and (2) if there are more implant-related complications in patients managed with bicolumnar plating compared to single-column plate fixation. This was a multi-centred retrospective comparative study. The study was conducted at two academic level 1 trauma centres. A total of 105 patients were identified to have surgical management of extra-articular distal humeral fractures Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 13A2 and AO/OTA 13A3). Patients were treated with traditional dual-column plating or a single-column posterolateral small-fragment pre-contoured locking plate used as a neutralisation device with at least five screws in the short distal segment. The patients' elbow functionality was assessed in terms of range of motion, union and alignment. In addition, the rate of complications between the groups including radial nerve palsy, implant-related complications (painful prominence and/or ulnar nerve neuritis) and elbow stiffness were compared. Patients treated with single-column plating had similar union rates and alignment. However, single-column plating resulted in a significantly better range of motion with less complications. The current study suggests that exposure/instrumentation of only the lateral column is a reliable and preferred technique. This technique allows for comparable union rates and alignment with increased elbow functionality and decreased number of complications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development and validation of a liquid chromatographic method for the simultaneous determination of aniracetam and its related substances in the bulk drug and a tablet formulation.

PubMed

Papandreou, Georgios; Zorpas, Kostas; Archontaki, Helen

2011-11-01

Simultaneous determination of aniracetam and its related impurities (2-pyrrolidinone, p-anisic acid, 4-p-anisamidobutyric acid and (p-anisoyl)-4-methyl-2-pyrrolidinone) was accomplished in the bulk drug and in a tablet formulation using a high performance liquid chromatographic method with UV detection. Separation was achieved on a Hypersil BDS-CN column (150 mm × 4.0 mm, 5 μm) using a gradient elution program with solvent A composed of phosphate buffer (pH 4.0; 0.010 M) and solvent B of acetonitrile-phosphate buffer (pH 4.0; 0.010 M) (90:10, v/v). The flow rate of the mobile phase was 1.0 mL min(-1) and the total elution time, including the column re-equilibration, was approximately 20 min. The UV detection wavelength was varied appropriately among 210, 250 and 280 nm. Injection volume was 20 μL and experiments were conducted at ambient temperature. The developed method was validated in terms of system suitability, selectivity, linearity, range, precision, accuracy, limits of detection and quantification for the impurities, short term and long term stability of the analytes in the prepared solutions and robustness, following the ICH guidelines. Therefore, the proposed method was suitable for the simultaneous determination of aniracetam and its studied related impurities. Copyright © 2011 Elsevier B.V. All rights reserved.

Experimental and modeling of the unsaturated transports of S-metolachlor and its metabolites in glaciofluvial vadose zone solids.

PubMed

Sidoli, Pauline; Lassabatere, Laurent; Angulo-Jaramillo, Rafael; Baran, Nicole

2016-07-01

The transport of pesticides to groundwater is assumed to be impacted by flow processes and geochemical interactions occurring in the vadose zone. In this study, the transport of S-metolachlor (SMOC) and its two metabolites ESA-metolachlor (MESA) and OXA-metolachlor (MOXA) in vadose zone materials of a glaciofluvial aquifer is studied at laboratory scale. Column experiments are used to study the leaching of a conservative tracer (bromide) and SMOC, MESA and MOXA under unsaturated conditions in two lithofacies, a bimodal gravel (Gcm,b) and a sand (S-x). Tracer experiments showed water fractionation into mobile and immobile compartments more pronounced in bimodal gravel columns. In both lithofacies columns, SMOC outflow is delayed (retardation factor>2) and mass balance reveals depletion (mass balance of 0.59 and 0.77 in bimodal gravel and sand, respectively). However, complete mass elution associated with retardation factors close to unity shows that there is no adsorption of MESA and MOXA in either lithofacies. SMOC transport is characterized by non-equilibrium sorption and sink term in both bimodal gravel and sand columns. Batch experiments carried out using agitation times consistent with column water residence times confirmed a time-dependence of SMOC sorption and high adsorption rates (>80%) of applied concentrations. Desorption experiments confirm the irreversibility of a major part of the SMOC adsorption onto particles, corresponding to the sink term in columns. In the bimodal gravel column, SMOC adsorption occurs mainly on reactive particles in contact with mobile water because of flow regionalization whereas in the sand column, there is pesticide diffusion to the immobile water. Such results clearly show that sorption mechanisms in the vadose zone solids below the soil are both solute and contact-time-dependent and are impacted by hydrodynamic conditions. The more rapid transport of MESA and MOXA to the aquifer would be controlled mainly by water flow through the unsaturated zone whereas SMOC transport is retarded by sorption processes within the vadose zone. Copyright © 2016 Elsevier B.V. All rights reserved.

The effects of used motor oil, silt, and the water mold Saprolegnia parasitica on the growth and survival of mole salamanders (genus Ambystoma).

PubMed

Lefcort, H; Hancock, K A; Maur, K M; Rostal, D C

1997-05-01

Amphibians appear to be declining worldwide. One cause of their decline may be used crankcase oil which leaks from motor vehicles and washes into ponds. Once in ponds, the oil may either be directly toxic to amphibians, or may indirectly affect them by disrupting food chains. The effects of oil may also be compounded by naturally occurring materials in the water column such as silt. Silt may interfere with respiration across gill surfaces. This study examined the effects of oil and silt on the growth and metamorphosis of larval mole salamanders, Ambystoma opacum and A. tigrinum tigrinum. In Experiment One it examined ponds with and without silty water and oil pollution to determine their suitability as habitats for salamander larvae. In Experiment Two it studied the effects of low levels of oil combined with silt on animals raised in the laboratory and fed prey items not raised in oil. In Experiment Three, it explored the effects of oil at an ecosystem level by raising the salamanders in the field in plastic micromesocosms that mimicked small ponds. Finally, in Experiment Four, in the laboratory, it examined the short-term survival of salamanders in high concentrations of oil. This study found that ponds containing oil and silt produce salamanders of reduced size and weight. Furthermore, while salamanders are relatively robust to the short term effects of large concentrations of used motor oil, oil has deleterious effects on the community and therefore exerts an indirect negative effect on salamanders. In the mi- cro-mesocosms containing oil, salamanders were smaller and weighed less than animals not raised in oil. Furthermore, silt results in reduced growth, earlier metamorphosis, and increased susceptibility to the water mold Saprolegnia parasitica.

Numerical and experimental analyses of lighting columns in terms of passive safety

NASA Astrophysics Data System (ADS)

Jedliński, Tomasz Ireneusz; Buśkiewicz, Jacek

2018-01-01

Modern lighting columns have a very beneficial influence on road safety. Currently, the columns are being designed to keep the driver safe in the event of a car collision. The following work compares experimental results of vehicle impact on a lighting column with FEM simulations performed using the Ansys LS-DYNA program. Due to high costs of experiments and time-consuming research process, the computer software seems to be very useful utility in the development of pole structures, which are to absorb kinetic energy of the vehicle in a precisely prescribed way.

Central executive involvement in children's spatial memory.

PubMed

Ang, Su Yin; Lee, Kerry

2008-11-01

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.

Fate of the fecal indicator Escherichia coli in irrigation with partially treated wastewater.

PubMed

Vergine, P; Saliba, R; Salerno, C; Laera, G; Berardi, G; Pollice, A

2015-11-15

Treated wastewater reuse is increasing in semi-arid regions as a response to the effects of climate change and increased competition for natural water resources. Investigating the fate of bacterial indicators is relevant to assess their persistence in the environment and possible transfer to groundwater or to the food chain. A long-term field-scale experimental campaign and a soil column test were carried out to evaluate the fate of the fecal indicator Escherichia coli (E. coli) in a cultivated soil when contaminated water resources are used for irrigation. For field experiments, fecal contamination was simulated by dosing the indicator to the effluent of a membrane bioreactor, thus simulating a filtration system's failure, and irrigating a test field where grass was grown. The presence of E. coli on grass and topsoil samples was monitored under different scenarios. For evaluating the fate of the same indicator in the subsoil, a set of soil columns was installed next to the field, operated, and monitored for E. coli concentration over time and along depth. Real municipal wastewater was used in this case as source of fecal contamination. Results showed that short- and medium-term effects on topsoil were strongly dependent on the concentration of E. coli in the irrigation water. Limited persistence and no relevant accumulation of the indicator on the grass and in the topsoil were observed. Watering events performed after fecal contamination did not influence significantly the decay in the topsoil, which followed a log-linear model. The trend of the E. coli concentrations in the leaching of the soil columns followed a log-linear model as well, suggesting bacterial decay as the dominant mechanism affecting the underground indicator's concentration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rapid regulation of brain-derived neurotrophic factor mRNA within eye-specific circuits during ocular dominance column formation.

PubMed

Lein, E S; Shatz, C J

2000-02-15

The neurotrophin brain-derived neurotrophic factor (BDNF) has emerged as a candidate retrograde signaling molecule for geniculocortical axons during the formation of ocular dominance columns. Here we examined whether neuronal activity can regulate BDNF mRNA in eye-specific circuits in the developing cat visual system. Dark-rearing throughout the critical period for ocular dominance column formation decreases levels of BDNF mRNA within primary visual cortex, whereas short-term (2 d) binocular blockade of retinal activity with tetrodotoxin (TTX) downregulates BDNF mRNA within the lateral geniculate nucleus (LGN) and visual cortical areas. Brief (6 hr to 2 d) monocular TTX blockade during the critical period and also in adulthood causes downregulation in appropriate eye-specific laminae in the LGN and ocular dominance columns within primary visual cortex. Monocular TTX blockade at postnatal day 23 also downregulates BDNF mRNA in a periodic fashion, consistent with recent observations that ocular dominance columns can be detected at these early ages by physiological methods. In contrast, 10 d monocular TTX during the critical period does not cause a lasting decrease in BDNF mRNA expression in columns pertaining to the treated eye, consistent with the nearly complete shift in physiological response properties of cortical neurons in favor of the unmanipulated eye known to result from long-term monocular deprivation. These observations demonstrate that BDNF mRNA levels can provide an accurate "molecular readout" of the activity levels of cortical neurons and are consistent with a highly local action of BDNF in strengthening and maintaining active synapses during ocular dominance column formation.

Programmable selectivity for GC with series-coupled columns using pulsed heating of the second column.

PubMed

Whiting, Joshua; Sacks, Richard

2003-05-15

A series-coupled ensemble of a nonpolar dimethyl polysiloxane column and a polar trifluoropropylmethyl polysiloxane column with independent at-column heating is used to obtain pulsed heating of the second column. For mixture component bands that are separated by the first column but coelute from the column ensemble, a temperature pulse is initiated after the first of the two components has crossed the column junction point and is in the second column, while the other component is still in the first column. This accelerates the band for the first component. If the second column cools sufficiently prior to the second component band crossing the junction, the second band experiences less acceleration, and increased separation is observed for the corresponding peaks in the ensemble chromatogram. High-speed at-column heating is obtained by wrapping the fused-silica capillary column with resistance heater wire and sensor wire. Rapid heating for a temperature pulse is obtained with a short-duration linear heating ramp of 1000 degrees C/min. During a pulse, the second-column temperature increases by 20-100 degrees C in a few seconds. Using a cold gas environment, cooling to a quiescent temperature of 30 degrees C can be obtained in approximately 25 s. The effects of temperature pulse initiation time and amplitude on ensemble peak separation and resolution are described. A series of appropriately timed temperature pulses is used to separate three coeluting pairs of components in a 13-component mixture.

Insensitivity of visual short-term memory to irrelevant visual information.

PubMed

Andrade, Jackie; Kemps, Eva; Werniers, Yves; May, Jon; Szmalec, Arnaud

2002-07-01

Several authors have hypothesized that visuo-spatial working memory is functionally analogous to verbal working memory. Irrelevant background speech impairs verbal short-term memory. We investigated whether irrelevant visual information has an analogous effect on visual short-term memory, using a dynamic visual noise (DVN) technique known to disrupt visual imagery (Quinn & McConnell, 1996b). Experiment I replicated the effect of DVN on pegword imagery. Experiments 2 and 3 showed no effect of DVN on recall of static matrix patterns, despite a significant effect of a concurrent spatial tapping task. Experiment 4 showed no effect of DVN on encoding or maintenance of arrays of matrix patterns, despite testing memory by a recognition procedure to encourage visual rather than spatial processing. Serial position curves showed a one-item recency effect typical of visual short-term memory. Experiment 5 showed no effect of DVN on short-term recognition of Chinese characters, despite effects of visual similarity and a concurrent colour memory task that confirmed visual processing of the characters. We conclude that irrelevant visual noise does not impair visual short-term memory. Visual working memory may not be functionally analogous to verbal working memory, and different cognitive processes may underlie visual short-term memory and visual imagery.

Long- and short-term effects of smothering and burial by drill cuttings on calcareous algae in a static-renewal test.

PubMed

Reynier, Márcia V; Tâmega, Frederico T S; Daflon, Sarah D A; Santos, Maurício A B; Coutinho, Ricardo; Figueiredo, Marcia A O

2015-07-01

Discharge of drill cuttings into the ocean during drilling of offshore oil wells can impact benthic communities through an increase in the concentrations of suspended particles in the water column and sedimentation of particles on the seafloor around the drilling installation. The present study assessed effects of water-based drill cuttings, barite, bentonite, and natural sediments on shallow- and deep-water calcareous algae in short-term (30 d) and long-term (90 d) experiments, using 2 species from Peregrino's oil field at Campos Basin, Brazil: Mesophyllum engelhartii and Lithothamnion sp. The results were compared with the shallow-water species Lithothamnion crispatum. Smothering and burial exposures were simulated. Oxygen production and fluorescence readings were recorded. Although less productive, M. engelhartii was as sensitive to stress as Lithothamnion sp. Mesophyllum engelhartii was sensitive to smothering by drill cuttings, barite, and bentonite after 60 d of exposure and was similarly affected by natural sediments after 90 d. These results indicate that smothering by sediments caused physical effects that might be attributable to partial light attenuation and partial restriction on gas exchange but did not kill the calcareous algae in the long term. However, 1-mo burial by either natural sediments or drill cuttings was sufficient after 60 d for both species to reduce oxygen production, and the algae were completely dead under both sources of sediments. © 2015 SETAC.

Ten Years of Observatory Science from Saanich Inlet on the VENUS Cabled Ocean Observatory

NASA Astrophysics Data System (ADS)

Dewey, R. K.; Tunnicliffe, V.; Macoun, P.; Round, A.

2016-02-01

The Saanich Inlet array of the VENUS cabled ocean observatory, maintained and operated by Ocean Networks Canada, was installed in February 2006, and in 2016 will have supported ten years of comprehensive interactive science. Representing the first in the present generation of cabled observing technologies, this coastal array has provided continuous high power and broadband communications to a variety of instrument platforms, hundreds of sensors, and enabled dozens of short, medium, and long-term studies. Saanich Inlet is a protected fjord with limited tidal action, resulting in an extremely productive environment, with strong seasonal chemical variations driven by episodic deep water renewal events and oxygen reduction processes. The breadth of the research has included microbial and benthic community dynamics, biogeochemical cycles, forensics, quantifying inter-annual variations, benthic-pelagic coupling, sensor testing, plankton dynamics, and bio-turbulence. Observatory measurements include core water properties (CTD & O2) and water-column echo-sounder records, as well as experiment-oriented deployments utilizing cameras, Gliders, Dopplers, hydrophones, and a variety of biogeochemical sensors. With a recently installed Buoy Profiler System for monitoring the entire water column, community plans continue with a dedicated Redox experiment through the 2016-17 seasons. Highlights from the dozens of research papers and theses will be presented to demonstrate the achievements enabled by a comprehensive coastal cabled observing system.

Comparison between the intra-particle diffusivity in the hydrophilic interaction chromatography and reversed phase liquid chromatography modes. Impact on the column efficiency.

PubMed

Gritti, Fabrice; Guiochon, Georges

2013-07-05

The effective diffusion coefficients of five low molecular weigh compounds (naphthalene, uracil, uridine, adenosine, and cytosine) were measured at room temperature in a 4.6mm×100mm column packed with 3.5μm XBridge HILIC particles. The mobile phase was an acetonitrile-water mixture (92.5/7.5, v/v) containing 10mM ammonium acetate and 0.02% acetic acid. Using a physically reliable model of effective diffusion in binary composite media (Torquato's model), accurate estimates of the intra-particle diffusivities in the HILIC particles were obtained as a function of the retention of these analytes. The HILIC diffusion coefficients were compared to those previously obtained for endcapped RPLC-C18 particles (5.0μm Gemini-C18). The experimental results confirm that adsorption sites are not localized in RPLC whereas they are so in the HILIC mode. In contrast to RPLC columns, HILIC columns provide longitudinal diffusion B/u terms that increase very little with increasing retention factors. This confirms the absence of surface diffusion in HILIC. The impact of intra-particle diffusivity on the column efficiency was projected in HILIC and RPLC on the basis of the measured intra-particle diffusivities and on the well established theory of band broadening in particulate columns. Accordingly, RPLC columns generate short-range eddy dispersion and solid-liquid mass transfer resistance Cu terms that increase less than do HILIC column with increasing retention factors. The HETP contribution caused by the trans-column structure heterogeneity is smaller in the HILIC than in the RPLC modes because the transverse excursion length is smaller in HILIC. Even though the overall column efficiencies are comparable in HILIC and RPLC, this study shows that the individual mass transfer phenomena are inherently different in the HILIC and the RPLC retention modes. Copyright © 2013 Elsevier B.V. All rights reserved.

Hurricane Arthur and its effect on the short term variation of pCO2

NASA Astrophysics Data System (ADS)

Lemay, Jonathan; Thomas, Helmuth; Craig, Susanne; Greenan, Blair; Fennel, Katja

2016-04-01

Seasonal changes in carbon cycling over the years have become better understood on the Scotian Shelf, however little is resolved in short term variation. Hourly measurements were collected from an autonomous moored instrument (CARIOCA) stationed at Halifax Line 2 (HL2), roughly 30km off the coast of Halifax for the 2014 year. Data from the 2007 deployment of the SeaHorse vertical sampling mooring at HL2 was also collected. Focusing on the storm event, Hurricane Arthur, July 5th 2014 reveals a significant drop in pCO2. With the shelf having carbon rich deep water, a reduction of pCO2 due to mixing went against current understanding. It was revealed that slightly above the mixed layer there is a sustained population of phytoplankton. When wind mixing from storms occurs, this population moves to the surface allowing greater light and nutrients for short term growth. This growth then reduces pCO2 for a short period of time until wind speeds slow down reducing mixing of the water column.

"One-pot" ethyl chloroformate derivatization and liquid-liquid extraction of reduced glutathione in erythrocyte and its quantitative GC-MS analysis.

PubMed

Manca, Alessandra; Alladio, Eugenio; Massarenti, Paola; Puccinelli, M Paola; De Francesco, Antonella; Del Grosso, Erika; Mengozzi, Giulio; Pazzi, Marco; Vincenti, Marco

2017-12-01

A simple "one-pot" derivatization and liquid-liquid extraction (LLE) procedure was developed for GC-MS analysis of reduced glutathione (GSH) analysis in erythrocytes. The metabolite was extracted by 5% (w/v) TCA, the supernatant treated with ECF and ethanol-pyridine media, the derivative separated and detected by gas chromatography-mass spectrometry using a short non-polar capillary GC column at a high column-head pressure. Total analysis time was 11min. The process was optimized by a Design of Experiment. The method was validated showing a good linearity over the 25.4-813.4μM concentration range, providing satisfactory results in terms of intra-day and inter-day precision as well as an optimal accuracy. The new method was evaluated in a pilot study involving patients with severe protein malnutrition. Comparison of this group with a group of healthy subjects revealed significantly lower GSH concentrations in erythrocytes in the former, thus proving that the described GC-MS method could be employed for fast and simple GSH analysis in clinical studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Gummed-up memory: chewing gum impairs short-term recall.

PubMed

Kozlov, Michail D; Hughes, Robert W; Jones, Dylan M

2012-01-01

Several studies have suggested that short-term memory is generally improved by chewing gum. However, we report the first studies to show that chewing gum impairs short-term memory for both item order and item identity. Experiment 1 showed that chewing gum reduces serial recall of letter lists. Experiment 2 indicated that chewing does not simply disrupt vocal-articulatory planning required for order retention: Chewing equally impairs a matched task that required retention of list item identity. Experiment 3 demonstrated that manual tapping produces a similar pattern of impairment to that of chewing gum. These results clearly qualify the assertion that chewing gum improves short-term memory. They also pose a problem for short-term memory theories asserting that forgetting is based on domain-specific interference given that chewing does not interfere with verbal memory any more than tapping. It is suggested that tapping and chewing reduce the general capacity to process sequences.

Kinetic investigation of narrow-bore columns packed with prototype sub-2 μm superficially porous particles with various shell thickness.

PubMed

Gritti, Fabrice; Omamogho, Jesse; Guiochon, Georges

2011-10-07

The recent successful breakthrough of sub-3 μm shell particles in HPLC has triggered considerable research efforts toward the design of new brands of core-shell particles. We investigated the mass transfer mechanism of a few analytes in narrow-bore columns packed with prototype 1.7 μm shell particles, made of 1.0, 1.2, and 1.4 μm solid nonporous cores surrounded by porous shells 350, 250, and 150 nm thick, respectively. Three probe solutes, uracil, naphthalene, and insulin, were chosen to assess the kinetic performance of these columns. Inverse size exclusion chromatography, peak parking experiments, and the numerical integration of the experimental peak profiles were carried out in order to measure the external, internal, and total column porosities, the true bulk diffusion coefficients of these analytes, the height equivalent to a theoretical plate, the longitudinal diffusion term, and the trans-particle mass transfer resistance term. The residual eddy diffusion term was measured by difference. The results show the existence of important trans-column velocity biases (7%) possibly due to the presence of particle multiplets in the slurry mixture used during the packing process. Our results illustrates some of the difficulties encountered by scientists preparing and packing shell particles into narrow-bore columns. Copyright © 2011 Elsevier B.V. All rights reserved.

Benchscale Assessment of the Efficacy of a Reactive Core Mat to Isolate PAH-spiked Aquatic Sediments.

PubMed

Meric, Dogus; Barbuto, Sara; Sheahan, Thomas C; Shine, James P; Alshawabkeh, Akram N

2014-01-01

This paper describes the results of a benchscale testing program to assess the efficacy of a reactive core mat (RCM) for short term isolation and partial remediation of contaminated, subaqueous sediments. The 1.25 cm thick RCM (with a core reactive material such as organoclay with filtering layers on top and bottom) is placed on the sediment, and approximately 7.5 - 10 cm of overlying soil is placed on the RCM for stability and protection. A set of experiments were conducted to measure the sorption characteristics of the mat core (organoclay) and sediment used in the experiments, and to determine the fate of semi-volatile organic contaminants and non-reactive tracers through the sediment and reactive mat. The experimental study was conducted on naphthalene-spiked Neponset River (Milton, MA) sediment. The results show nonlinear sorption behavior for organoclay, with sorption capacity increasing with increasing naphthalene concentration. Neponset River sediment showed a notably high sorption capacity, likely due to the relatively high organic carbon fraction (14%). The fate and transport experiments demonstrated the short term efficiency of the reactive mat to capture the contamination that is associated with the post-capping period during which the highest consolidation-induced advective flux occurs, driving solid particles, pore fluid and soluble contaminants toward the reactive mat. The goal of the mat placement is to provide a physical filtering and chemically reactive layer to isolate contamination from the overlying water column. An important finding is that because of the high sorption capacity of the Neponset River sediment, the physical filtering capability of the mat is as critical as its chemical reactive capacity.

An integrated wastewater reuse concept combining natural reclamation techniques, membrane filtration and metal oxide adsorption.

PubMed

Sperlich, A; Zheng, X; Ernst, M; Jekel, M

2008-01-01

In a Sino-German research project, a sustainable water reclamation concept was developed for different applications of municipal water reuse at the Olympic Green 2008 in Beijing, China. Results from pilot-scale experiments in Beijing and Berlin show that selective nutrient removal by adsorption onto granular ferric hydroxide (GFH) after a membrane bioreactor (MBR) can maintain a total phosphorus concentration of <0.03 microg L(-1) P, thus preventing eutrophication of artificial lakes. Operation time of GFH adsorption columns can be extended by regeneration using sodium hydroxide solution. A subsequent ultrafiltration (UF) membrane after bank filtration creates an additional barrier for pathogens and allows for further urban reuse applications such as toilet flushing. Short term bank / bio-filtration prior to UF is shown to effectively remove biopolymers and reduce membrane fouling. Copyright IWA Publishing 2008.

The experimental verification on the shear bearing capacity of exposed steel column foot

NASA Astrophysics Data System (ADS)

Xijin, LIU

2017-04-01

In terms of the shear bearing capacity of the exposed steel column foot, there are many researches both home and abroad. However, the majority of the researches are limited to the theoretical analysis sector and few of them make the experimental analysis. In accordance with the prototype of an industrial plant in Beijing, this paper designs the experimental model. The experimental model is composed of six steel structural members in two groups, with three members without shear key and three members with shear key. The paper checks the shear bearing capacity of two groups respectively under different axial forces. The experiment shows: The anchor bolt of the exposed steel column foot features relatively large shear bearing capacity which could not be neglected. The results deducted through calculation methods proposed by this paper under two situations match the experimental results in terms of the shear bearing capacity of the steel column foot. Besides, it also proposed suggestions on revising the Code for Design of Steel Structure in the aspect of setting the shear key in the steel column foot.

Study of Ozone Layer Variability near St. Petersburg on the Basis of SBUV Satellite Measurements and Numerical Simulation (2000-2014)

NASA Astrophysics Data System (ADS)

Virolainen, Y. A.; Timofeyev, Y. M.; Smyshlyaev, S. P.; Motsakov, M. A.; Kirner, O.

2017-12-01

A comparison between the numerical simulation results of ozone fields with different experimental data makes it possible to estimate the quality of models for their further use in reliable forecasts of ozone layer evolution. We analyze time series of satellite (SBUV) measurements of the total ozone column (TOC) and the ozone partial columns in two atmospheric layers (0-25 and 25-60 km) and compare them with the results of numerical simulation in the chemistry transport model (CTM) for the low and middle atmosphere and the chemistry climate model EMAC. The daily and monthly average ozone values, short-term periods of ozone depletion, and long-term trends of ozone columns are considered; all data sets relate to St. Petersburg and the period between 2000 and 2014. The statistical parameters (means, standard deviations, variations, medians, asymmetry parameter, etc.) of the ozone time series are quite similar for all datasets. However, the EMAC model systematically underestimates the ozone columns in all layers considered. The corresponding differences between satellite measurements and EMAC numerical simulations are (5 ± 5)% and (7 ± 7)% and (1 ± 4)% for the ozone column in the 0-25 and 25-60 km layers, respectively. The correspondent differences between SBUV measurements and CTM results amount to (0 ± 7)%, (1 ± 9)%, and (-2 ± 8)%. Both models describe the sudden episodes of the ozone minimum well, but the EMAC accuracy is much higher than that of the CTM, which often underestimates the ozone minima. Assessments of the long-term linear trends show that they are close to zero for all datasets for the period under study.

Understanding Women's Differing Experiences of Distress after Colposcopy: A Qualitative Interview Study.

PubMed

O'Connor, Mairead; Waller, Jo; Gallagher, Pamela; Martin, Cara M; O'Leary, John J; D'Arcy, Tom; Prendiville, Walter; Flannelly, Grainne; Sharp, Linda

2015-01-01

Women who have an abnormal cervical cytology test may be referred for a colposcopy. Accumulating evidence suggests some women may experience distress after colposcopy. This exploratory study examined women's differing experiences of post-colposcopy distress with the aim of identifying factors that are predictive of, or protective against, distress. We carried out semistructured, qualitative interviews with 23 women who had undergone colposcopies. Interviews were transcribed verbatim, coded, and analyzed thematically. The Framework Approach was used to summarize and organize the data and identify emerging higher order themes. Two forms of post-colposcopy distress emerged: 1) short term and 2) long term. Short-term distress was experienced immediately after the colposcopy and in the days afterward, and was usually related to the physical experience of the colposcopy. Long-term distress typically persisted over time and was related to concerns about fertility, cervical cancer, and sexual intercourse. The drivers of short-term and long-term distress differed. Factors related to short-term distress were feeling unprepared for the procedure, having a negative experience of the procedure, and attending the clinic alone. Factors related to long-term distress were future intentions to have (more) children, having physical after-effects of the procedure that impacted on the woman's life, and being under on-going clinic surveillance. Absence of these factors (e.g., being accompanied to the clinic) was protective against short- and long-term distress. Colposcopy can lead to short- and long-term post-procedural distress for some women. We identified a range of factors, some potentially modifiable, that seem to influence the chances of experiencing distress. These results may inform the development of strategies or interventions aimed at preventing or minimizing distress after colposcopy and related procedures. Copyright © 2015 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

Orthographic Structure and Reading Experience Affect the Transfer from Iconic to Short Term Memory

ERIC Educational Resources Information Center

Lefton, Lester A.; Spragins, Anne B.

1974-01-01

The basic hypothesis of these experiments was that the processing strategy for the transfer of alphabetic material from iconic storage to short-term memory involves a sequential left-to-right factor that develops with increases in experience with reading. (Author)

Short-Term International Experiences and Teacher Language Awareness

ERIC Educational Resources Information Center

Harbon, Lesley

2007-01-01

This research study had as its focus the impact of a short-term international experience on teacher language awareness (TLA). In-country intensive immersion experiences were considered beneficial for language teacher professional development. This project examined the Australian teachers' perceptions of their teaching and home-stay experiences…

Short segment pedicle screw instrumentation and augmentation vertebroplasty in lumbar burst fractures: an experience

PubMed Central

Akbar, Saleem; Dhar, Shabir A.

2008-01-01

To assess the efficacy and feasibility of vertebroplasty and posterior short-segment pedicle screw fixation for the treatment of traumatic lumbar burst fractures. Short-segment pedicle screw instrumentation is a well described technique to reduce and stabilize thoracic and lumbar spine fractures. It is relatively a easy procedure but can only indirectly reduce a fractured vertebral body, and the means of augmenting the anterior column are limited. Hardware failure and a loss of reduction are recognized complications caused by insufficient anterior column support. Patients with traumatic lumbar burst fractures without neurologic deficits were included. After a short segment posterior reduction and fixation, bilateral transpedicular reduction of the endplate was performed using a balloon, and polymethyl methacrylate cement was injected. Pre-operative and post-operative central and anterior heights were assessed with radiographs and MRI. Sixteen patients underwent this procedure, and a substantial reduction of the endplates could be achieved with the technique. All patients recovered uneventfully, and the neurologic examination revealed no deficits. The post-operative radiographs and magnetic resonance images demonstrated a good fracture reduction and filling of the bone defect without unwarranted bone displacement. The central and anterior height of the vertebral body could be restored to 72 and 82% of the estimated intact height, respectively. Complications were cement leakage in three cases without clinical implications and one superficial wound infection. Posterior short-segment pedicle fixation in conjunction with balloon vertebroplasty seems to be a feasible option in the management of lumbar burst fractures, thereby addressing all the three columns through a single approach. Although cement leakage occurred but had no clinical consequences or neurological deficit. PMID:18193300

Short-term Responses of Posidonia australis to Changes in Light Quality

PubMed Central

Strydom, Simone; McMahon, Kathryn M.; Kendrick, Gary A.; Statton, John; Lavery, Paul S.

2018-01-01

Seagrass meadows are highly productive ecosystems that provide ecosystem services to the coastal zone but are declining globally, particularly due to anthropogenic activities that reduce the quantity of light reaching seagrasses, such as dredging, river discharge and eutrophication. Light quality (the spectral composition of the light) is also altered by these anthropogenic stressors as the differential attenuation of wavelengths of light is caused by materials within the water column. This study addressed the effect of altered light quality on different life-history stages of the seagrass Posidonia australis, a persistent, habitat-forming species in Australia. Aquarium-based experiments were conducted to determine how adult shoots and seedlings respond to blue (peak λ = 451 nm); green (peak λ = 522 nm); yellow (peak λ = 596 nm) and red (peak λ = 673 nm) wavelengths with a control of full-spectrum light (λ = 400 – 700 nm, at 200 μmol photons m-2 s-1). Posidonia australis adults did not respond to changes in light quality relative to full-spectrum light, demonstrating a capacity to obtain enough photons from a range of wavelengths across the visible spectrum to maintain short-term growth at high irradiances. Posidonia australis seedlings (<4 months old) grown in blue light showed a significant increase in xanthophyll concentrations when compared to plants grown in full-spectrum, demonstrating a pigment acclimation response to blue light. These results differed significantly from negative responses to changes in light quality recently described for Halophila ovalis, a colonizing seagrass species. Persistent seagrasses such as P. australis, appear to be better at tolerating short-term changes in light quality compared to colonizing species when sufficient PPFD is present. PMID:29387070

Pre-Service Teachers' Perceptions of a Short-Term International Experience Programme

ERIC Educational Resources Information Center

Barkhuizen, Gary; Feryok, Anne

2006-01-01

Short-term international experiences (STIE) are becoming a regular, sometimes required, feature of pre-service language teacher education programmes. Often inappropriately termed "immersion programmes", they aim to give teachers the opportunity to improve their language proficiency in the language they will teach, to develop their…

The Demonstration of Short-Term Consolidation.

ERIC Educational Resources Information Center

Jolicoeur, Pierre; Dell'Acqua, Roberto

1998-01-01

Results of seven experiments involving 112 college students or staff using a dual-task approach provide evidence that encoding information into short-term memory involves a distinct process termed short-term consolidation (STC). Results suggest that STC has limited capacity and that it requires central processing mechanisms. (SLD)

Comparison of twin-cell centrifugal partition chromatographic columns with different cell volume.

PubMed

Goll, Johannes; Audo, Gregoire; Minceva, Mirjana

2015-08-07

Two twin-cell centrifugal partition chromatographic columns (SCPC 250 and SCPE-250-BIO, Armen Instrument, France) with the same column volume but different cell size and number were compared in terms of stationary phase retention and column efficiency. The columns were tested with two types of solvent systems: a commonly used organic solvent based biphasic system from the ARIZONA solvent system family and a polymer/salt based aqueous two phase system (ATPS). The efficiency of the columns was evaluated by pulse injection experiments of two benzenediols (pyrocatechol and hydroquinone) in the case of the ARIZONA system and a protein mixture (myoglobin and lysozyme) in the case of the ATPS. As result of high stationary phase retention, the column with the lower number of larger twin-cells (SCPE-250-BIO) is suitable for protein separations using ATPS. On the other hand, due to higher column efficiency, the column with the greater number of smaller cells (SCPC 250) is superior for batch elution separations performed with standard liquid-liquid chromatography organic solvent based biphasic systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Bubble Shuttle: A newly discovered transport mechanism, which transfers microorganisms from the sediment into the water column

NASA Astrophysics Data System (ADS)

Schmale, O.; Stolle, C.; Leifer, I.; Schneider von Deimling, J.; Kiesslich, K.; Krause, S.; Frahm, A.; Treude, T.

2013-12-01

The diversity and abundance of methanotrophic microorganisms is well studied in the aquatic environment, indicating their importance in biogeochemical cycling of methane in the sediment and the water column. However, whether methanotrophs are distinct populations in these habitats or are exchanged between benthic and pelagic environments, remains an open question. Therefore, field studies were conducted at the 'Rostocker Seep' site (Coal Oil Point seep area, California, USA) to test our hypothesis that methane-oxidizing microorganisms can be transported by gas bubbles from the sediment into the water column. The natural methane emanating location 'Rostocker Seep' showed a strong surface water oversaturation in methane with respect to the atmospheric equilibrium. Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) analyzes were performed to determine the abundance of aerobic and anaerobic methanotrophic microorganisms. Aerobic methane oxidizing bacteria were detected in the sediment and the water column, whereas anaerobic methanotrophs were detected exclusively in the sediment. The key device of the project was the newly developed "Bubble Catcher" used to collect naturally emanating gas bubbles at the sea floor together with particles attached to the bubble surface rim. Bubble Catcher experiments were carried out directly above a natural bubble release spot and on a reference site at which artificially released gas bubbles were caught, which had no contact with the sediment. CARD-FISH analyzes showed that aerobic methane oxidizing bacteria were transported by gas bubbles from the sediment into the water column. In contrast anaerobic methanotrophs were not detected in the bubble catcher. Further results indicate that this newly discovered Bubble Shuttle transport mechanism might influence the distribution pattern of methanotrophic microorganisms in the water column and even at the air-sea interface. Methane seep areas are often characterized by an elevated abundance of methane-oxidizing microorganisms, which consume a considerable amount of methane before it escapes into the atmosphere. Based on our study we hypothesize that the Bubble Shuttle transport mechanism contributes to this pelagic methane sink by a sediment-water column transfer of methane oxidizing microorganisms. Furthermore, this Bubble Shuttle may influence the methanotrophic community in the water column after massive short-term submarine inputs of methane (e.g. release of methane from bore holes). Especially in deep-sea regions, where the abundance of methane oxidizing microorganisms in the water column is low in general, Bubble Shuttle may inject a relevant amount of methane oxidizing microorganisms into the water column during massive inputs, supporting indirectly the turnover of this greenhouse active trace gas in the submarine environment.

Short-Term International Experience (STIE) and Students' Understanding of Quality Early Childhood Service Provision

ERIC Educational Resources Information Center

Sims, Margaret; Nishida, Yukiyo

2018-01-01

Exposing pre-service teachers to international professional experiences through a short-term visiting programme serves to challenge their understandings of good quality practice through disturbing assumptions and expectations previously formed through experiences in their own country/culture. Much of the research in international study focuses on…

Phosphorus cycling and partitioning in an oligotrophic Everglades wetland ecosystem: A radioisotope tracing study

USGS Publications Warehouse

Noe, G.B.; Scinto, L.J.; Taylor, J.; Childers, D.L.; Jones, R.D.

2003-01-01

1. Our goal was to quantify short-term phosphorus (P) partitioning and identify the ecosystem components important to P cycling in wetland ecosystems. To do this, we added P radiotracer to oligotrophic, P-limited Everglades marshes. 32PO4 was added to the water column in six 1-m2 enclosed mesocosms located in long-hydroperiod marshes of Shark River Slough, Everglades National Park. Ecosystem components were then repeatedly sampled over 18 days. 2. Water column particulates (>0.45 ??m) incorporated radiotracer within the first minute after dosing and stored 95-99% of total water column 32P activity throughout the study. Soluble (<0.45 ??m) 32P in the water column, in contrast, was always <5% of the 32P in surface water. Periphyton, both floating and attached to emergent macrophytes, had the highest specific activity of 32P (Bq g-131P) among the different ecosystem components. Fish and aquatic macroinvertebrates also had high affinity for P, whereas emergent macrophytes, soil and flocculent detrital organic matter (floc) had the lowest specific activities of radiotracer. 3. Within the calcareous, floating periphyton mats, 81% of the initial 32P uptake was associated with Ca, but most of this 32P entered and remained within the organic pool (Ca-associated = 14% of total) after 1 day. In the floc layer, 32P rapidly entered the microbial pool and the labile fraction was negligible for most of the study. 4. Budgeting of the radiotracer indicated that 32P moved from particulates in the water column to periphyton and floc and then to the floc and soil over the course of the 18 days incubations. Floc (35% of total) and soil (27%) dominated 32P storage after 18 days, with floating periphyton (12%) and surface water (10%) holding smaller proportions of total ecosystem 32P. 5. To summarise, oligotrophic Everglades marshes exhibited rapid uptake and retention of labile 32P. Components dominated by microbes appear to control short-term P cycling in this oligotrophic ecosystem.

Study of the footprints of short-term variation in XCO2 observed by TCCON sites using NIES and FLEXPART atmospheric transport models

NASA Astrophysics Data System (ADS)

Belikov, Dmitry A.; Maksyutov, Shamil; Ganshin, Alexander; Zhuravlev, Ruslan; Deutscher, Nicholas M.; Wunch, Debra; Feist, Dietrich G.; Morino, Isamu; Parker, Robert J.; Strong, Kimberly; Yoshida, Yukio; Bril, Andrey; Oshchepkov, Sergey; Boesch, Hartmut; Dubey, Manvendra K.; Griffith, David; Hewson, Will; Kivi, Rigel; Mendonca, Joseph; Notholt, Justus; Schneider, Matthias; Sussmann, Ralf; Velazco, Voltaire A.; Aoki, Shuji

2017-01-01

The Total Carbon Column Observing Network (TCCON) is a network of ground-based Fourier transform spectrometers (FTSs) that record near-infrared (NIR) spectra of the sun. From these spectra, accurate and precise observations of CO2 column-averaged dry-air mole fractions (denoted XCO2) are retrieved. TCCON FTS observations have previously been used to validate satellite estimations of XCO2; however, our knowledge of the short-term spatial and temporal variations in XCO2 surrounding the TCCON sites is limited. In this work, we use the National Institute for Environmental Studies (NIES) Eulerian three-dimensional transport model and the FLEXPART (FLEXible PARTicle dispersion model) Lagrangian particle dispersion model (LPDM) to determine the footprints of short-term variations in XCO2 observed by operational, past, future and possible TCCON sites. We propose a footprint-based method for the collocation of satellite and TCCON XCO2 observations and estimate the performance of the method using the NIES model and five GOSAT (Greenhouse Gases Observing Satellite) XCO2 product data sets. Comparison of the proposed approach with a standard geographic method shows a higher number of collocation points and an average bias reduction up to 0.15 ppm for a subset of 16 stations for the period from January 2010 to January 2014. Case studies of the Darwin and Reunion Island sites reveal that when the footprint area is rather curved, non-uniform and significantly different from a geographical rectangular area, the differences between these approaches are more noticeable. This emphasises that the collocation is sensitive to local meteorological conditions and flux distributions.

Short- and long-term memory contributions to immediate serial recognition: evidence from serial position effects.

PubMed

Purser, Harry; Jarrold, Christopher

2010-04-01

A long-standing body of research supports the existence of separable short- and long-term memory systems, relying on phonological and semantic codes, respectively. The aim of the current study was to measure the contribution of long-term knowledge to short-term memory performance by looking for evidence of phonologically and semantically coded storage within a short-term recognition task, among developmental samples. Each experimental trial presented 4-item lists. In Experiment 1 typically developing children aged 5 to 6 years old showed evidence of phonologically coded storage across all 4 serial positions, but evidence of semantically coded storage at Serial Positions 1 and 2. In a further experiment, a group of individuals with Down syndrome was investigated as a test case that might be expected to use semantic coding to support short-term storage, but these participants showed no evidence of semantically coded storage and evidenced phonologically coded storage only at Serial Position 4, suggesting that individuals with Down syndrome have a verbal short-term memory capacity of 1 item. Our results suggest that previous evidence of semantic effects on "short-term memory performance" does not reflect semantic coding in short-term memory itself, and provide an experimental method for researchers wishing to take a relatively pure measure of verbal short-term memory capacity, in cases where rehearsal is unlikely.

The relationship between vocabulary and short-term memory measures in monolingual and bilingual speakers

PubMed Central

Kaushanskaya, Margarita; Blumenfeld, Henrike K.; Marian, Viorica

2012-01-01

Previous studies have indicated that bilingualism may influence the efficiency of lexical access in adults. The goals of this research were (1) to compare bilingual and monolingual adults on their native-language vocabulary performance, and (2) to examine the relationship between short-term memory skills and vocabulary performance in monolinguals and bilinguals. In Experiment 1, English-speaking monolingual adults and simultaneous English–Spanish bilingual adults were administered measures of receptive English vocabulary and of phonological short-term memory. In Experiment 2, monolingual adults were compared to sequential English–Spanish bilinguals, and were administered the same measures as in Experiment 1, as well as a measure of expressive English vocabulary. Analyses revealed comparable levels of performance on the vocabulary and the short-term memory measures in the monolingual and the bilingual groups across both experiments. There was a stronger effect of digit-span in the bilingual group than in the monolingual group, with high-span bilinguals outperforming low-span bilinguals on vocabulary measures. Findings indicate that bilingual speakers may rely on short-term memory resources to support word retrieval in their native language more than monolingual speakers. PMID:22518091

The baric probe: a novel long-term implantable intracranial pressure monitor with ultrasound-based interrogation.

PubMed

Limbrick, David D; Lake, Stephen; Talcott, Michael; Alexander, Benjamin; Wight, Samuel; Willie, Jon T; Richard, William D; Genin, Guy M; Leuthardt, Eric C

2012-12-01

Prompt diagnosis of shunt malfunction is critical in preventing neurological morbidity and death in individuals with hydrocephalus; however, diagnostic methods for this condition remain limited. For several decades, investigators have sought a long-term, implantable intracranial pressure (ICP) monitor to assist in the diagnosis of shunt malfunction, but efforts have been impeded by device complexity, marked measurement drift, and limited instrumentation lifespan. In the current report, the authors introduce an entirely novel, simple, compressible gas design that addresses each of these problems. The device described herein, termed the "baric probe," consists of a subdural fluid bladder and multichannel indicator that monitors the position of an air-fluid interface (AFI). A handheld ultrasound probe is used to interrogate the baric probe in vivo, permitting noninvasive ICP determination. To assess the function of device prototypes, ex vivo experiments were conducted using a water column, and short- and long-term in vivo experiments were performed using a porcine model with concurrent measurements of ICP via a fiberoptic monitor. Following a toe region of approximately 2 cm H(2)O, the baric probe's AFI demonstrated a predictable linear relationship to ICP in both ex vivo and in vivo models. After a 2-week implantation of the device, this linear relationship remained robust and reproducible. Further, changes in ICP were observed with the baric probe, on average, 3 seconds in advance of the fiberoptic ICP monitor reading. The authors demonstrate "proof-of-concept" and feasibility for the baric probe, a long-term implantable ICP monitor designed to facilitate the prompt and accurate diagnosis of shunt malfunction. The baric probe showed a consistent linear relationship between ICP and the device's AFI in ex vivo and short- and long-term in vivo models. With a low per-unit cost, a reduced need for radiography or CT, and an indicator that can be read with a handheld ultrasound probe that interfaces with any smart phone, the baric probe promises to simplify the care of patients with shunt-treated hydrocephalus throughout both the developed and the developing world.

Mutagenicity of fractionated test material from the synthetic fuel technology with bacterial systems

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

Rao, T.K.; Young, J.A.; Hardigree, A.A.

1978-01-01

The predictive value of short-term genetic tests, such as the Salmonella and Escherichia coli (K-12, 343/113) systems including microsomal activation, is well documented. We have applied the short-term testing to various crude products and effluents from the synthetic fuel technologies. Class fractionation and column chromatography of the test materials and the coupled bioassays can be used to identify the most active fractions (collaborative effort with Analytical Chemistry Division). Reversion at the histidine locus for Salmonella was assayed with each fraction and the results are expressed in units of revertants (strain TA98) per milligram of the starting material (organic content) includingmore » metabolic activation with a crude rat liver preparation. Results obtained with the Salmonella system were validated by employing E. coli strains auxotrophic for arginine. Genetic activity is seen with a variety of fractions, largely the basic and neutral (PAH) components. Total activity varies from process to process, thus, the short-term genetic test can be considered a useful prescreen for potential biohazard of various effluents both in plants and in the immediate plant environment.« less

Short-term Memory as a Processing Shift

ERIC Educational Resources Information Center

Lewis-Smith, Marion Quinn

1975-01-01

The series of experiments described here examined the predictions for free recall from sequential models and the shift formulation, focusing on the roles of short- and long-term memory in the primacy/recency shift and on the effects of expectancies on short- and long-term memory. (Author/RK)

Root induced changes of effective 1D hydraulic properties in a soil column.

PubMed

Scholl, P; Leitner, D; Kammerer, G; Loiskandl, W; Kaul, H-P; Bodner, G

Roots are essential drivers of soil structure and pore formation. This study aimed at quantifying root induced changes of the pore size distribution (PSD). The focus was on the extent of clogging vs. formation of pores during active root growth. Parameters of Kosugi's lognormal PSD model were determined by inverse estimation in a column experiment with two cover crops (mustard, rye) and an unplanted control. Pore dynamics were described using a convection-dispersion like pore evolution model. Rooted treatments showed a wider range of pore radii with increasing volumes of large macropores >500 μm and micropores <2.5 μm, while fine macropores, mesopores and larger micropores decreased. The non-rooted control showed narrowing of the PSD and reduced porosity over all radius classes. The pore evolution model accurately described root induced changes, while structure degradation in the non-rooted control was not captured properly. Our study demonstrated significant short term root effects with heterogenization of the pore system as dominant process of root induced structure formation. Pore clogging is suggested as a partial cause for reduced pore volume. The important change in micro- and large macropores however indicates that multiple mechanic and biochemical processes are involved in root-pore interactions.

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

Bornea, A.; Zamfirache, M.; Stefan, L.

ICIT (Institute for Cryogenics and Isotopic Technologies) has used its experience in cryogenic water distillation process to propose a similar process for hydrogen distillation that can be used in detritiation technologies. This process relies on the same packages but a stainless filling is tested instead of the phosphorous bronze filling used for water distillation. This paper presents two types of packages developed for hydrogen distillation, both have a stainless filling but it differs in terms of density, exchange surface and specific volume. Performance data have been obtained on laboratory scale. In order to determine the characteristics of the package, themore » installation was operated in the total reflux mode, for different flow rate for the liquid. There were made several experiments considering different operating conditions. Samples extracted at the top and bottom of cryogenic distillation column allowed mathematical processing to determine the separation performance. The experiments show a better efficiency for the package whose exchange surface was higher and there were no relevant differences between both packages as the operating pressure of the cryogenic column was increasing. For a complete characterization of the packages, future experiments will be considered to determine performance at various velocities in the column and their correlation with the pressure in the column. We plan further experiments to separate tritium from the mixture of isotopes DT, having in view that our goal is to apply this results to a detritiation plant.« less

Establishment of a short-term global health nursing education experience: impact on students' ways of knowing.

PubMed

Wagner, Linda D; Christensen, Stacy E

2015-05-01

The Essentials of Baccalaureate Education for Professional Nursing recognizes that with the increased globalization of health care, professional nurses have to be prepared to practice in multicultural environments and must possess the skills needed to provide culturally competent care. Thirty-five baccalaureate nursing students participated in a short-term course abroad to Jamaica over a period of 3 years. The impact of such an experience on ways of knowing was assessed in 20 participants, using a visual analog scale. Students believed that the short-term course abroad experience had a positive impact on their personal knowing and that they developed an understanding of a health care system different from their own, while reflecting on issues of social justice. Results provide evidence of the positive impact on short-term course abroad trips on students' ways of knowing. Critical to establishment of these experiences is evaluation of their merit through documentation of student learning outcomes. Copyright 2015, SLACK Incorporated.

Updating and feature overwriting in short-term memory for timbre.

PubMed

Mercer, Tom; McKeown, Denis

2010-11-01

Previous research has demonstrated a potent, stimulus-specific form of interference in short-term auditory memory. This effect has been interpreted in terms of interitem confusion and grouping, but the present experiments suggested that interference might be a feature-specific phenomenon. Participants compared standard and comparison tones over a 10-sec interval and were required to determine whether they differed in timbre. A single interfering distractor tone was presented either 50 msec or 8 sec after the offset of the standard (Experiment 1) or 2 sec prior to its onset (Experiment 2). The distractor varied in the number of features it shared with the standard and comparison, and this proved critical, since performance on the task was greatly impaired when the distractor either consisted of novel, unshared features (Experiment 1) or contained the distinguishing feature of the comparison tone (Experiments 1 and 2). These findings were incompatible with earlier accounts of forgetting but were fully explicable by the recent timbre memory model, which associates interference in short-term auditory memory with an "updating" process and feature overwriting. These results suggest similarities with the mechanisms that underlie forgetting in verbal short-term memory.

[Short-term memory characteristics of vibration intensity tactile perception on human wrist].

PubMed

Hao, Fei; Chen, Li-Juan; Lu, Wei; Song, Ai-Guo

2014-12-25

In this study, a recall experiment and a recognition experiment were designed to assess the human wrist's short-term memory characteristics of tactile perception on vibration intensity, by using a novel homemade vibrotactile display device based on the spatiotemporal combination vibration of multiple micro vibration motors as a test device. Based on the obtained experimental data, the short-term memory span, recognition accuracy and reaction time of vibration intensity were analyzed. From the experimental results, some important conclusions can be made: (1) The average short-term memory span of tactile perception on vibration intensity is 3 ± 1 items; (2) The greater difference between two adjacent discrete intensities of vibrotactile stimulation is defined, the better average short-term memory span human wrist gets; (3) There is an obvious difference of the average short-term memory span on vibration intensity between the male and female; (4) The mechanism of information extraction in short-term memory of vibrotactile display is to traverse the scanning process by comparison; (5) The recognition accuracy and reaction time performance of vibrotactile display compares unfavourably with that of visual and auditory. The results from this study are important for designing vibrotactile display coding scheme.

Visual Short-Term Cued Recall Memory in Infancy.

ERIC Educational Resources Information Center

Brody, Leslie R.

1981-01-01

The visual short-term cued recall memory of 8-, 12-, and 16-month-olds was assessed in two experiments using an operant indirect delayed-reaction procedure. In each experiment, 12- and 16-month olds performed better than chance, whereas 8-month-old infants did not. (Author/DB)

Short-term memory in autism spectrum disorder.

PubMed

Poirier, Marie; Martin, Jonathan S; Gaigg, Sebastian B; Bowler, Dermot M

2011-02-01

Three experiments examined verbal short-term memory in comparison and autism spectrum disorder (ASD) participants. Experiment 1 involved forward and backward digit recall. Experiment 2 used a standard immediate serial recall task where, contrary to the digit-span task, items (words) were not repeated from list to list. Hence, this task called more heavily on item memory. Experiment 3 tested short-term order memory with an order recognition test: Each word list was repeated with or without the position of 2 adjacent items swapped. The ASD group showed poorer performance in all 3 experiments. Experiments 1 and 2 showed that group differences were due to memory for the order of the items, not to memory for the items themselves. Confirming these findings, the results of Experiment 3 showed that the ASD group had more difficulty detecting a change in the temporal sequence of the items. (c) 2010 APA, all rights reserved.

Multiple Roles for Time in Short-Term Memory: Evidence from Serial Recall of Order and Timing

ERIC Educational Resources Information Center

Farrell, Simon

2008-01-01

Three experiments are reported that examine the relationship between short-term memory for time and order information, and the more specific claim that order memory is driven by a timing signal. Participants were presented with digits spaced irregularly in time and postcued (Experiments 1 and 2) or precued (Experiment 3) to recall the order or…

Investigation of holdup and axial dispersion of liquid phase in a catalytic exchange column using radiotracer technique.

PubMed

Kumar, Rajesh; Pant, H J; Goswami, Sunil; Sharma, V K; Dash, A; Mishra, S; Bhanja, K; Mohan, Sadhana; Mahajani, S M

2017-03-01

Holdup and axial dispersion of liquid phase in a catalytic exchange column were investigated by measuring residence time distributions (RTD) using a radiotracer technique. RTD experiments were independently carried out with two different types of packings i.e. hydrophobic water-repellent supported platinum catalyst and a mixture (50% (v/v)) of hydrophobic catalyst and a hydrophillic wettable packing were used in the column. Mean residence times and hold-ups of the liquid phase were estimated at different operating conditions. Axial dispersion model (ADM) and axial dispersion with exchange model (ADEM) were used to simulate the measured RTD data. Both the models were found equally suitable to describe the measured data. The degree of axial mixing was estimated in terms of Peclet number (Pe) and Bodenstein number (Bo). Based on the obtained parameters of the ADM, correlations for total liquid hold-up (H T ) and axial mixing in terms of Bo were proposed for design and scale up of the full-scale catalytic exchange column. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chancellor Water Colloids: Characterization and Radionuclide Associated Transport

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

Reimus, Paul William; Boukhalfa, Hakim

2014-09-26

Column transport experiments were conducted in which water from the Chancellor nuclear test cavity was transported through crushed volcanic tuff from Pahute Mesa. In one experiment, the cavity water was spiked with solute 137Cs, and in another it was spiked with 239/240Pu(IV) nanocolloids. A third column experiment was conducted with no radionuclide spike at all, although the 137Cs concentrations in the water were still high enough to quantify in the column effluent. The radionuclides strongly partitioned to natural colloids present in the water, which were characterized for size distribution, mass concentration, zeta potential/surface charge, critical coagulation concentration, and qualitative mineralogy.more » In the spiked water experiments, the unanalyzed portion of the high-concentration column effluent samples were combined and re-injected into the respective columns as a second pulse. This procedure was repeated again for a third injection. Measurable filtration of the colloids was observed after each initial injection of the Chancellor water into the columns, but the subsequent injections (spiked water experiments only) exhibited no apparent filtration, suggesting that the colloids that remained mobile after relatively short transport distances were more resistant to filtration than the initial population of colloids. It was also observed that while significant desorption of 137Cs from the colloids occurred after the first injection in both the spiked and unspiked waters, subsequent injections of the spiked water exhibited much less 137Cs desorption (much greater 137Cs colloid-associated transport). This result suggests that the 137Cs that remained associated with colloids during the first injection represented a fraction that was more strongly adsorbed to the mobile colloids than the initial 137Cs associated with the colloids. A greater amount of the 239/240Pu desorbed from the colloids during the second column injection compared to the first injection, but then desorption decreased significantly in the third injection. This result suggests that the Pu(IV) nanocolloids probably at least partially dissolved during and after the first injection, resulting in enhanced desorption from the colloids during the second injection, but by the third injection the Pu started following the same trend that was observed for 137Cs. The experiments suggest a transport scale dependence in which mobile colloids and colloid-associated radionuclides observed at downstream points along a flow path have a greater tendency to remain mobile along the flow path than colloids and radionuclides observed at upstream points. This type of scale dependence may help explain observations of colloid-facilitated Pu transport over distances of up to 2 km at Pahute Mesa.« less

Industrial Work Placement in Higher Education: A Study of Civil Engineering Student Engagement

ERIC Educational Resources Information Center

Tennant, Stuart; Murray, Mike; Gilmour, Bob; Brown, Linda

2018-01-01

For civil engineering undergraduates, short-term industrial work placement provides an invaluable learning experience. Notwithstanding the near-universal endorsement of short-term placement programmes, the resulting experience is rarely articulated through the student voice. This article provides an analysis of 174 questionnaires returned by…

Cultural and Cognitive Development in Short-Term Study Abroad: Illuminating the 360 Experience

ERIC Educational Resources Information Center

Burton, Susan

2012-01-01

The three articles in this dissertation investigate leading others through developmental opportunities by facilitating their engagement in intercultural challenges. Specifically the research explores the meaning followers make of developmental challenges during short-term study abroad experiences and encounters with diversity. Data in the form of…

A Short-Term Study Abroad Program for School Counseling Students

ERIC Educational Resources Information Center

Cunningham, Teddi; Caldwell, Charmaine; Geltner, Jill

2011-01-01

Well planned, short-term study abroad programs can benefit school counseling students through exposure to new and different cultural experiences. Students gain knowledge and skills that will help them serve the diverse cultural groups found in public school settings. The objective of the short-term study abroad program described in this article…

Short-term memory across eye blinks.

PubMed

Irwin, David E

2014-01-01

The effect of eye blinks on short-term memory was examined in two experiments. On each trial, participants viewed an initial display of coloured, oriented lines, then after a retention interval they viewed a test display that was either identical or different by one feature. Participants kept their eyes open throughout the retention interval on some blocks of trials, whereas on others they made a single eye blink. Accuracy was measured as a function of the number of items in the display to determine the capacity of short-term memory on blink and no-blink trials. In separate blocks of trials participants were instructed to remember colour only, orientation only, or both colour and orientation. Eye blinks reduced short-term memory capacity by approximately 0.6-0.8 items for both feature and conjunction stimuli. A third, control, experiment showed that a button press during the retention interval had no effect on short-term memory capacity, indicating that the effect of an eye blink was not due to general motoric dual-task interference. Eye blinks might instead reduce short-term memory capacity by interfering with attention-based rehearsal processes.

Evidence of linked biogeochemical and hydrological processes in homogeneous and layered vadose zone systems

NASA Astrophysics Data System (ADS)

McGuire, J. T.; Hansen, D. J.; Mohanty, B. P.

2010-12-01

Understanding chemical fate and transport in the vadose zone is critical to protect groundwater resources and preserve ecosystem health. However, prediction can be challenging due to the dynamic hydrologic and biogeochemical nature of the vadose zone. Additional controls on hydrobiogeochemical processes are added by subsurface structural heterogeneity. This study uses repacked soil column experiments to quantify linkages between microbial activity, geochemical cycling and hydrologic flow. Three “short” laboratory soil columns were constructed to evaluate the effects of soil layering: a homogenized medium-grained sand, homogenized organic-rich loam, and a sand-over-loam layered column. In addition, two “long” columns were constructed using either gamma-irradiated (sterilized) or untreated sediments to evaluate the effects of both soil layers and the presence of microorganisms. The long columns were packed identically; a medium-grained sand matrix with two vertically separated and horizontally offset lenses of organic-rich loam. In all 5 columns, downward and upward infiltration of water was evaluated to simulate rainfall and rising water table events respectively. In-situ colocated probes were used to measure soil water content, matric potential, Eh, major anions, ammonium, Fe2+, and total sulfide. Enhanced biogeochemical cycling was observed in the short layered column versus the short, homogeneous columns, and enumerations of iron and sulfate reducing bacteria were 1-2 orders of magnitude greater. In the long columns, microbial activity caused mineral bands and produced insoluble gases that impeded water flow through the pores of the sediment. Capillary barriers, formed around the lenses due to soil textural differences, retarded water flow rates through the lenses. This allowed reducing conditions to develop, evidenced by the production of Fe2+ and S2-. At the fringes of the lenses, Fe2+ oxidized to form Fe(III)-oxide bands that further retarded water flux. No such mineral bands developed in the sterilized column. As a consequence, water content in the lenses of the sterilized column was half that of the other column and flow rates through the lenses were an order of magnitude lower. This flow impedance limited the interaction and mixing of groundwater with infiltrating vadose zone water and led to the formation of geochemically distinct water masses residing in relatively close proximity to one another. Results provide a specific examples of the direct impact of biogeochemical cycling on water flow in the vadose zone and vice versa. In addition, these demonstrate that the presence of layers in vadose zone environments may be an important control on overall chemical fate and transport in subsurface systems.

Cortical metabolic activity matches the pattern of visual suppression in strabismus.

PubMed

Adams, Daniel L; Economides, John R; Sincich, Lawrence C; Horton, Jonathan C

2013-02-27

When an eye becomes deviated in early childhood, a person does not experience double vision, although the globes are aimed at different targets. The extra image is prevented from reaching perception in subjects with alternating exotropia by suppression of each eye's peripheral temporal retina. To test the impact of visual suppression on neuronal activity in primary (striate) visual cortex, the pattern of cytochrome oxidase (CO) staining was examined in four macaques raised with exotropia by disinserting the medial rectus muscles shortly following birth. No ocular dominance columns were visible in opercular cortex, where the central visual field is represented, indicating that signals coming from the central retina in each eye were perceived. However, the border strips at the edges of ocular dominance columns appeared pale, reflecting a loss of activity in binocular cells from disruption of fusion. In calcarine cortex, where the peripheral visual field is represented, there were alternating pale and dark bands resembling ocular dominance columns. To interpret the CO staining pattern, [(3)H]proline was injected into the right eye in two monkeys. In the right calcarine cortex, the pale CO columns matched the labeled proline columns of the right eye. In the left calcarine cortex, the pale CO columns overlapped the unlabeled columns of the left eye in the autoradiograph. Therefore, metabolic activity was reduced in the ipsilateral eye's ocular dominance columns which serve peripheral temporal retina, in a fashion consistent with the topographic organization of suppression scotomas in humans with exotropia.

What do short-term and long-term relationships look like? Building the relationship coordination and strategic timing (ReCAST) model.

PubMed

Eastwick, Paul W; Keneski, Elizabeth; Morgan, Taylor A; McDonald, Meagan A; Huang, Sabrina A

2018-05-01

Close relationships research has examined committed couples (e.g., dating relationships, marriages) using intensive methods that plot relationship development over time. But a substantial proportion of people's real-life sexual experiences take place (a) before committed relationships become "official" and (b) in short-term relationships; methods that document the time course of relationships have rarely been applied to these contexts. We adapted a classic relationship trajectory-plotting technique to generate the first empirical comparisons between the features of people's real-life short-term and long-term relationships across their entire timespan. Five studies compared long-term and short-term relationships in terms of the timing of relationship milestones (e.g., flirting, first sexual intercourse) and the occurrence/intensity of important relationship experiences (e.g., romantic interest, strong sexual desire, attachment). As romantic interest was rising and partners were becoming acquainted, long-term and short-term relationships were indistinguishable. Eventually, romantic interest in short-term relationships plateaued and declined while romantic interest in long-term relationships continued to rise, ultimately reaching a higher peak. As relationships progressed, participants evidenced more features characteristic of the attachment-behavioral system (e.g., attachment, caregiving) in long-term than short-term relationships but similar levels of other features (e.g., sexual desire, self-promotion, intrasexual competition). These data inform a new synthesis of close relationships and evolutionary psychological perspectives called the Relationship Coordination and Strategic Timing (ReCAST) model. ReCAST depicts short-term and long-term relationships as partially overlapping trajectories (rather than relationships initiated with distinct strategies) that differ in their progression along a normative relationship development sequence. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Paper Microzone Plates as Analytical Tools for Studying Enzyme Stability: A Case Study on the Stabilization of Horseradish Peroxidase Using Trehalose and SU-8 Epoxy Novolac Resin.

PubMed

Ganaja, Kirsten A; Chaplan, Cory A; Zhang, Jingyi; Martinez, Nathaniel W; Martinez, Andres W

2017-05-16

Paper microzone plates in combination with a noncontact liquid handling robot were demonstrated as tools for studying the stability of enzymes stored on paper. The effect of trehalose and SU-8 epoxy novolac resin (SU-8) on the stability of horseradish peroxidase (HRP) was studied in both a short-term experiment, where the activity of various concentrations of HRP dried on paper were measured after 1 h, and a long-term experiment, where the activity of a single concentration of HRP dried and stored on paper was monitored for 61 days. SU-8 was found to stabilize HRP up to 35 times more than trehalose in the short-term experiment for comparable concentrations of the two reagents, and a 1% SU-8 solution was found to stabilize HRP approximately 2 times more than a 34% trehalose solution in both short- and long-term experiments. The results suggest that SU-8 is a promising candidate for use as an enzyme-stabilizing reagent for paper-based diagnostic devices and that the short-term experiment could be used to quickly evaluate the capacity of various reagents for stabilizing enzymes to identify and characterize new enzyme-stabilizing reagents.

Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

NASA Technical Reports Server (NTRS)

Huz, Kateryna

2014-01-01

RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better detection via good peak separation with a longer run time is a better asset than moderate peak separation with a shorter run time. Even given that RESOLVE is highly interested in water and that mission timeline is of significant importance given the short seven-to-ten-day mission timeline, worse detection with an 8m column may lead to overlooking other substances existing on the moon that could advance planetary science. Thus, I recommend the 20m column. However, if mission timeline and water separation are deemed the highest priority, the 8m column should be selected due to its ability to separate water within a shorter run time than the 20m column.

Expect the Unexpected: International Short-Term Study Course Pedagogies and Practices

ERIC Educational Resources Information Center

Roholt, Ross VeLure; Fisher, Colleen

2013-01-01

Given the United States' population changes and the increasing impact of globalization, international context and experience in the MSW curriculum are essential. Gaining popularity as a vehicle for such experience are short-term international courses, defined as educational trips outside the United States lasting from 1 to 3 weeks. To achieve…

The Impact of Pointing on the Short-Term Memory (STM) of Heterophonic Homographs

ERIC Educational Resources Information Center

Vaknin-Nusbaum, Vered; Miller, Paul

2014-01-01

This study entailed two short-term memory (STM) experiments investigating the importance of vowel diacritics for the temporary retention of three distinct Hebrew word list types: heterophonic homographs, non-homographs and homophonic homographs. Eighty university students participated in each experiment, with half of them tested with word lists…

Short- and Long-Term Effects of Cumulative Finals on Student Learning

ERIC Educational Resources Information Center

Khanna, Maya M.; Brack, Amy S. Badura; Finken, Laura L.

2013-01-01

In two experiments, we examined the benefits of cumulative and noncumulative finals on students' short- and long-term course material retention. In Experiment 1, we examined results from course content exams administered immediately after course finals. Course sections including cumulative finals had higher content exam scores than sections…

Identity Matters in a Short-Term, International Service-Learning Program

ERIC Educational Resources Information Center

Mather, Peter C.; Karbley, Megan; Yamamoto, Makiko

2012-01-01

This study explores the role that identity and the identity development process play in a short-term, international service-learning experience. Employing narrative inquiry, two of the co-authors, student participants in a 2-week service-learning program in Honduras, describe and interpret their service-learning experience in the context of life…

U.S.-Based Short-Term Public Health Cultural Immersion Experience for Chinese Undergraduate Students

ERIC Educational Resources Information Center

Powell, Dorothy Lewis; Biederman, Donna J.

2017-01-01

A U.S. and Chinese university developed a short-term student exchange program in public/community health. The program--which consisted of lectures, seminars, field trips, cross-cultural experiences, and a synthesis excursion--resulted in high levels of program satisfaction, increased intrapersonal awareness, and skill acquisition. Program content…

Short-Term Memory Retrievals and Expectation in On-Line Sentence Comprehension: The Effects of Recent Linguistic Context

ERIC Educational Resources Information Center

Bartek, Brian D.

2011-01-01

Understanding how short-term memory shapes sentence comprehension processes is a long-standing topic in psycholinguistics. This thesis pursues new insights on two facets of short-term memory's role in sentence comprehension: (a) The first four experiments search for, and obtain, concrete evidence that locality effects, or increased integration…

Short-Term Memory for Order but Not for Item Information Is Impaired in Developmental Dyslexia

ERIC Educational Resources Information Center

Hachmann, Wibke M.; Bogaerts, Louisa; Szmalec, Arnaud; Woumans, Evy; Duyck, Wouter; Job, Remo

2014-01-01

Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short-to long-term memory (Szmalec et al. "Journal of Experimental Psychology: Learning, Memory, & Cognition" 37(5): 1270-1279, 2011). At the same time, models of short-term memory…

Immobilization of uranium and arsenic by injectible iron and hydrogen stimulated autotrophic sulphate reduction

NASA Astrophysics Data System (ADS)

Burghardt, D.; Simon, E.; Knöller, K.; Kassahun, A.

2007-12-01

The main object of the study was the development of a long-term efficient and inexpensive in-situ immobilization technology for uranium (U) and arsenic (As) in smaller and decentralized groundwater discharges from abandoned mining processing sites. Therefore, corrosion of grey cast iron (gcFe) and nano-scale iron particles (naFe) as well as hydrogen stimulated autotrophic sulphate reduction (aSR) were investigated. Two column experiments with sulphate reducing bacterias (SRB) (biotic gcFe , biotic naFe) and one abiotic gcFe-column experiment were performed. In the biotic naFe column, no particle translocation was observed and a temporary but intensive naFe corrosion indicated by a decrease in Eh, a pH increase and H 2 evolution. Decreasing sulphate concentrations and 34S enrichment in the column effluent indicated aSR. Fe(II) retention could be explained by siderite and consequently FeS precipitation by geochemical modeling (PhreeqC). U and As were completely immobilised within the biotic naFe column. In the biotic gcFe column, particle entrapment in open pore spaces resulted in a heterogeneous distribution of Fe-enriched zones and an increase in permeability due to preferential flow. However, Fe(II) concentrations in the effluent indicated a constant and lasting gcFe corrosion. An efficient immobilization was found for As, but not for U.

Dissolved phosphorus retention of light-weight expanded shale and masonry sand used in subsurface flow treatment wetlands.

PubMed

Forbes, Margaret G; Dickson, Kenneth R; Golden, Teresa D; Hudak, Paul; Doyle, Robert D

2004-02-01

Using surface flow constructed wetlands for long-term phosphorus (P) retention presents a challenge due to the fact that P is stored primarily in the sediments. Subsurface flow wetlands have the potential to greatly increase P retention; however, the substrate needs to have both high hydraulic conductivity and high P sorption capacity. The objective of our study was to assess the P retention capacity of two substrates, masonry sand and lightweight expanded shale. We used sorption/desorption isotherms, flow-through column experiments, and pilot-scale wetlands to quantify P retained from treated municipal wastewater. Langmuir sorption isotherms predicted that the expanded shale has a maximum sorption capacity of 971 mg/kg and the masonry sand 58.8 mg/kg. In column desorption and column flow-through experiments, the masonry sand desorbed P when exposed to dilute P solutions. The expanded shale, however, had very little desorption and phosphorus did not break through the columns during our experiment. In pilot cells, masonry sand retained (mean +/- standard deviation) 45 +/- 62 g P/m2/yr and expanded shale retained 164 +/- 110 g P/m2/yr. We conclude that only the expanded shale would be a suitable substrate for retaining P in a subsurface flow wetland.

Multi-Column Experimental Test Bed Using CaSDB MOF for Xe/Kr Separation

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

Welty, Amy Keil; Greenhalgh, Mitchell Randy; Garn, Troy Gerry

Processing of spent nuclear fuel produces off-gas from which several volatile radioactive components must be separated for further treatment or storage. As part of the Off-gas Sigma Team, parallel research at INL and PNNL has produced several promising sorbents for the selective capture of xenon and krypton from these off-gas streams. In order to design full-scale treatment systems, sorbents that are promising on a laboratory scale must be proven under process conditions to be considered for pilot and then full-scale use. To that end, a bench-scale multi-column system with capability to test multiple sorbents was designed and constructed at INL.more » This report details bench-scale testing of CaSDB MOF, produced at PNNL, and compares the results to those reported last year using INL engineered sorbents. Two multi-column tests were performed with the CaSDB MOF installed in the first column, followed with HZ-PAN installed in the second column. The CaSDB MOF column was placed in a Stirling cryocooler while the cryostat was employed for the HZ-PAN column. Test temperatures of 253 K and 191 K were selected for the first column while the second column was held at 191 K for both tests. Calibrated volume sample bombs were utilized for gas stream analyses. At the conclusion of each test, samples were collected from each column and analyzed for gas composition. While CaSDB MOF does appear to have good capacity for Xe, the short time to initial breakthrough would make design of a continuous adsorption/desorption cycle difficult, requiring either very large columns or a large number of smaller columns. Because of the tenacity with which Xe and Kr adhere to the material once adsorbed, this CaSDB MOF may be more suitable for use as a long-term storage solution. Further testing is recommended to determine if CaSDB MOF is suitable for this purpose.« less

Americium, Cesium, and Plutonium Colloid-Facilitated Transport in a Groundwater/Bentonite/Fracture Fill Material System: Column Experiments and Model Results

NASA Astrophysics Data System (ADS)

Dittrich, T. M.; Boukhalfa, H.; Reimus, P. W.

2014-12-01

The objective of this study was to investigate and quantify the effects of desorption kinetics and colloid transport on radionuclides with different sorption affinities. We focused on quantifying transport mechanisms important for upscaling in time and distance. This will help determine the long-term fate and transport of radionuclides to aid in risk assessments. We selected a fractured/weathered granodiorite at the Grimsel Test Site (GTS) in Switzerland as a model crystalline rock repository system because the system has been thoroughly studied and field experiments involving radionuclides have already been conducted. Working on this system provides a unique opportunity to compare lab experiments with field-scale observations. Weathered fracture fill material (FFM) and bentonite used as backfill at the GTS were characterized (e.g., BET, SEM/EDS, QXRD), and batch and breakthrough column experiments were conducted. Solutions were prepared in synthetic groundwaters that matched the natural water chemistry. FFM samples were crushed, rinsed, sieved (150-355 μm), and equilibrated with synthetic groundwater. Bentonite was crushed, sodium-saturated, equilibrated with synthetic groundwater, and settled to yield a stable suspension. Suspensions were equilibrated with Am, Cs, or Pu. All experiments were conducted with Teflon®materials to limit sorption to system components. After radionuclide/colloid injections reached stability, radionuclide-free solutions were injected to observe the desorption and release behavior. Aliquots of effluent were measured for pH, colloid concentration, and total and dissolved radionuclides. Unanalyzed effluent from the first column was then injected through a second column of fresh material. The process was repeated for a third column and the results of all three breakthrough curves were modeled with a multi-site/multi-rate MATLAB code to elucidate the sorption rate coefficients and binding site densities of the bentonite colloids and fracture fill material. Nearly 50% of the sorbed Am was exchanged from the colloids to the fracture filling material in each of the three columns; whereas, less Cs and Pu was desorbed with each pass through a new column. Using a two-site kinetic model allowed for interrogation of desorption rates and dominant transport parameters.

Short-Term Compassion Training Increases Prosocial Behavior in a Newly Developed Prosocial Game

PubMed Central

Leiberg, Susanne; Klimecki, Olga; Singer, Tania

2011-01-01

Compassion has been suggested to be a strong motivator for prosocial behavior. While research has demonstrated that compassion training has positive effects on mood and health, we do not know whether it also leads to increases in prosocial behavior. We addressed this question in two experiments. In Experiment 1, we introduce a new prosocial game, the Zurich Prosocial Game (ZPG), which allows for repeated, ecologically valid assessment of prosocial behavior and is sensitive to the influence of reciprocity, helping cost, and distress cues on helping behavior. Experiment 2 shows that helping behavior in the ZPG increased in participants who had received short-term compassion training, but not in participants who had received short-term memory training. Interindividual differences in practice duration were specifically related to changes in the amount of helping under no-reciprocity conditions. Our results provide first evidence for the positive impact of short-term compassion training on prosocial behavior towards strangers in a training-unrelated task. PMID:21408020

Conventional and narrow bore short capillary columns with cyclodextrin derivatives as chiral selectors to speed-up enantioselective gas chromatography and enantioselective gas chromatography-mass spectrometry analyses.

PubMed

Bicchi, Carlo; Liberto, Erica; Cagliero, Cecilia; Cordero, Chiara; Sgorbini, Barbara; Rubiolo, Patrizia

2008-11-28

The analysis of complex real-world samples of vegetable origin requires rapid and accurate routine methods, enabling laboratories to increase sample throughput and productivity while reducing analysis costs. This study examines shortening enantioselective-GC (ES-GC) analysis time following the approaches used in fast GC. ES-GC separations are due to a weak enantiomer-CD host-guest interaction and the separation is thermodynamically driven and strongly influenced by temperature. As a consequence, fast temperature rates can interfere with enantiomeric discrimination; thus the use of short and/or narrow bore columns is a possible approach to speeding-up ES-GC analyses. The performance of ES-GC with a conventional inner diameter (I.D.) column (25 m length x 0.25 mm I.D., 0.15 microm and 0.25 microm d(f)) coated with 30% of 2,3-di-O-ethyl-6-O-tert-butyldimethylsilyl-beta-cyclodextrin in PS-086 is compared to those of conventional I.D. short column (5m length x 0.25 mm I.D., 0.15 microm d(f)) and of different length narrow bore columns (1, 2, 5 and 10 m long x 0.10 mm I.D., 0.10 microm d(f)) in analysing racemate standards of pesticides and in the flavour and fragrance field and real-world-samples. Short conventional I.D. columns gave shorter analysis time and comparable or lower resolutions with the racemate standards, depending mainly on analyte volatility. Narrow-bore columns were tested under different analysis conditions; they provided shorter analysis time and resolutions comparable to those of conventional I.D. ES columns. The narrow-bore columns offering the most effective compromise between separation efficiency and analysis time are the 5 and 2m columns; in combination with mass spectrometry as detector, applied to lavender and bergamot essential oil analyses, these reduced analysis time by a factor of at least three while separation of chiral markers remained unaltered.

Questioning short-term memory and its measurement: Why digit span measures long-term associative learning.

PubMed

Jones, Gary; Macken, Bill

2015-11-01

Traditional accounts of verbal short-term memory explain differences in performance for different types of verbal material by reference to inherent characteristics of the verbal items making up memory sequences. The role of previous experience with sequences of different types is ostensibly controlled for either by deliberate exclusion or by presenting multiple trials constructed from different random permutations. We cast doubt on this general approach in a detailed analysis of the basis for the robust finding that short-term memory for digit sequences is superior to that for other sequences of verbal material. Specifically, we show across four experiments that this advantage is not due to inherent characteristics of digits as verbal items, nor are individual digits within sequences better remembered than other types of individual verbal items. Rather, the advantage for digit sequences stems from the increased frequency, compared to other verbal material, with which digits appear in random sequences in natural language, and furthermore, relatively frequent digit sequences support better short-term serial recall than less frequent ones. We also provide corpus-based computational support for the argument that performance in a short-term memory setting is a function of basic associative learning processes operating on the linguistic experience of the rememberer. The experimental and computational results raise questions not only about the role played by measurement of digit span in cognition generally, but also about the way in which long-term memory processes impact on short-term memory functioning. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Language differences in verbal short-term memory do not exclusively originate in the process of subvocal rehearsal.

PubMed

Thorn, A S; Gathercole, S E

2001-06-01

Language differences in verbal short-term memory were investigated in two experiments. In Experiment 1, bilinguals with high competence in English and French and monolingual English adults with extremely limited knowledge of French were assessed on their serial recall of words and nonwords in both languages. In all cases recall accuracy was superior in the language with which individuals were most familiar, a first-language advantage that remained when variation due to differential rates of articulation in the two languages was taken into account. In Experiment 2, bilinguals recalled lists of English and French words with and without concurrent articulatory suppression. First-language superiority persisted under suppression, suggesting that the language differences in recall accuracy were not attributable to slower rates of subvocal rehearsal in the less familiar language. The findings indicate that language-specific differences in verbal short-term memory do not exclusively originate in the subvocal rehearsal process. It is suggested that one source of language-specific variation might relate to the use of long-term knowledge to support short-term memory performance.

Stiffening of short small-size circular composite steel–concrete columns with shear connectors

PubMed Central

Younes, Sherif M.; Ramadan, Hazem M.; Mourad, Sherif A.

2015-01-01

An experimental program was conducted to investigate the effect of shear connectors’ distribution and method of load application on load–displacement relationship and behavior of thin-walled short concrete-filled steel tube (CFT) columns when subjected to axial load. The study focused on the compressive strength of the CFT columns and the efficiency of the shear stud in distribution of the load between the concrete core and steel tube. The study showed that the use of shear connectors enhanced slightly the axial capacity of CFT columns. It is also shown that shear connectors have a great effect on load distribution between the concrete and steel tubes. PMID:27222757

Two-dimensional preparative liquid chromatography system for preparative separation of minor amount components from complicated natural products.

PubMed

Qiu, Ying-Kun; Chen, Fang-Fang; Zhang, Ling-Ling; Yan, Xia; Chen, Lin; Fang, Mei-Juan; Wu, Zhen

2014-04-11

An on-line comprehensive two-dimensional preparative liquid chromatography system was developed for preparative separation of minor amount components from complicated natural products. Medium-pressure liquid chromatograph (MPLC) was applied as the first dimension and preparative HPLC as the second one, in conjunction with trapping column and makeup pump. The performance of the trapping column was evaluated, in terms of column size, dilution ratio and diameter-height ratio, as well as system pressure from the view of medium pressure liquid chromatograph. Satisfactory trapping efficiency can be achieved using a commercially available 15 mm × 30 mm i.d. ODS pre-column. The instrument operation and the performance of this MPLC×preparative HPLC system were illustrated by gram-scale isolation of crude macro-porous resin enriched water extract of Rheum hotaoense. Automated multi-step preparative separation of 25 compounds, whose structures were identified by MS, (1)H NMR and even by less-sensitive (13)C NMR, could be achieved in a short period of time using this system, exhibiting great advantages in analytical efficiency and sample treatment capacity compared with conventional methods. Copyright © 2014 Elsevier B.V. All rights reserved.

Short- and Mid-Term Effects of Violent Victimization on Delinquency: A Multilevel Growth-Curve Modeling Approach.

PubMed

Kim, Young S; Lo, Celia C

2016-10-01

The present study investigates how adolescents' experiences of violent victimization exert short- and mid-term effects on their involvement in delinquency. The study compares and contrasts delinquency trajectories of youths whose experiences of violent victimization differ. A multilevel growth-curve modeling approach is applied to analyze data from five waves of the National Youth Survey. The results show that, although delinquency involvement increases as youths experience violent victimization, delinquency trajectories differ with the type of violent victimization, specifically, parental versus non-parental victimization. Violent victimization by parents produced a sharp initial decline in delinquency (short-term effect) followed by a rapid acceleration (mid-term effect). In turn, non-parental violence showed a stable trend over time. The findings have important implications for prevention and treatment services. © The Author(s) 2015.

Maximising Intercultural Learning in Short Term International Placements: Findings Associated with Orientation Programs, Guided Reflection and Immersion

ERIC Educational Resources Information Center

Campbell, Coral J. L.; Walta, Caroline

2015-01-01

Short-term international practicum experience is now a feature of many university education programs in Australia in an attempt to engage students with the growing multi-cultural aspects of Australian life. The stated purposes of such practicum experiences generally highlight intercultural learning, which is associated with the development of…

Short-Term International Service-Learning: Faculty Perceptions of and Pedagogical Strategies for the Design and Implementation of Successful Learning Experiences

ERIC Educational Resources Information Center

Van Cleave, Thomas Jacob

2013-01-01

Faculty-led short-term international service-learning (STISL) experiences are thought to have great potential in developing students' global citizenship through combining study abroad and community service pedagogies. However, thorough investigation of the pedagogical strategies employed in STISL courses to achieve such outcomes has yet to be…

Nordic Experiences: Participants' Expectations and Experiences of Short-Term Study Abroad Programs

ERIC Educational Resources Information Center

Rahikainen, Katariina; Hakkarainen, Kai

2013-01-01

The purpose of this study was to investigate Finnish high school students' and teachers' perceptions of the effects of short-term Nordic study abroad programs in which they had participated. The data presented were based on a "mixed-methods strategy." The data set consisted of responses from 158 students and 92 teachers to a specifically…

The Precategorical Nature of Visual Short-Term Memory

ERIC Educational Resources Information Center

Quinlan, Philip T.; Cohen, Dale J.

2016-01-01

We conducted a series of recognition experiments that assessed whether visual short-term memory (VSTM) is sensitive to shared category membership of to-be-remembered (tbr) images of common objects. In Experiment 1 some of the tbr items shared the same basic level category (e.g., hand axe): Such items were no better retained than others. In the…

An investigation of the impact of selected prereading activities on student content learning through laboratory activities

NASA Astrophysics Data System (ADS)

Kass, Jesse (Shaya)

This study investigated whether two prereading activities impacted student learning from hands-on science activities. The study was based on constructivist learning theory. Based on the work of Piaget, it was hypothesized that students who activated prior knowledge would learn more from the activities. Based on the work of Vygotsky it was hypothesized that students who talk more and write more would learn more from the activity. The K-W-L chart and anticipation guide strategies were used with eighth grade students at Graves Middle School in Whittier, California before learning about levers and convection currents. D. M. Ogle (1986) created the three-column K-W-L chart to have students activate prior knowledge. In the first column, the students write what they already know about a subject, in the second column, the students write what they want to know about the subject, and the students complete the third column after learning about a subject by writing answers to the questions that they asked in the second column. Duffelmeyer (1994) created the anticipation guide based on Herber's (1978) reasoning guide. In the anticipation guide, the teacher creates three or four sentences that convey the major ideas of the topic and the students either agree or disagree with the statements. After learning about the topic, students revisit their answers and decide if they were correct or incorrect and they must defend their choices. This research used the Solomon (1947) four-square design and compared both the experimental groups to a control group that simply discussed the concepts before completing the activity. The research showed no significant difference between the control group and either of the treatment groups. The reasons for the lack of significant differences are considered. It was hypothesized that since the students were unfamiliar with the prereading activities and did not have much experience with using either writing-to-learn or talking-to-learn strategies, the short-term intervention was not effective. Directions for future study are considered.

Part 1: Vadose-zone column studies of toluene (enhanced bioremediation) in a shallow unconfined aquifer

USGS Publications Warehouse

Tindall, J.A.; Friedel, M.J.; Szmajter, R.J.; Cuffin, S.M.

2005-01-01

The objectives of the laboratory study described in this paper were (1) to determine the effectiveness of four nutrient solutions and a control in stimulating the microbial degradation of toluene in the unsaturated zone as an alternative to bioremediation methodologies such as air sparging, in situ vitrification, or others (Part I), and (2) to compare the effectiveness of the addition of the most effective nutrient solution from Part I (modified Hoagland type, nitrate-rich) and hydrogen peroxide (H2O2) on microbial degradation of toluene for repeated, simulated spills in the unsaturated zone (Part II). For Part 1, fifteen columns (30-cm diameter by 150-cm height), packed with air-dried, 0.25-mm, medium-fine sand, were prepared to simulate shallow unconfined aquifer conditions. Toluene (10 mL) was added to the surface of each column, and soil solution and soil gas samples were collected from the columns every third day for 21 days. On day 21, a second application of toluene (10 mL) was made, and the experiment was run for another 21 days. Solution 4 was the most effective for microbial degradation in Part I. For Part II, three columns were designated nutrient-rich 3-day toluene columns and received toluene injections every 3 days; three columns were designated as nutrient-rich 7-day columns and received toluene injections every 7 days; and two columns were used as controls to which no nutrient was added. As measured by CO2 respiration, the initial benefits for aerobic organisms from the O2 enhancement were sustained by the bacteria for only a short period of time (about 8 days). Degradation benefits from the nutrient solution were sustained throughout the experiment. The O2 and nutrient-enhanced columns degraded significantly more toluene than the control columns when simulating repeated spills onto the unsaturated zone, and demonstrated a potentially effective in situ bioremediation technology when used immediately or within days after a spill. The combined usage of H 2O2 and nitrate-rich nutrients served to effectively maximize natural aerobic and anaerobic metabolic processes that biodegrade hydrocarbons in petroleum-contaminated media. Applications of this technology in the field may offer economical advantages to other, more intrusive abatement technologies. ?? Springer 2005.

Dynamic characterization of the Chamousset rock column before its fall

NASA Astrophysics Data System (ADS)

Levy, C.; Baillet, L.; Jongmans, D.

2009-04-01

The rockfall of Chamousset (volume of 21000m3 ) occurred on November 10, 2007, affecting the 300 m high Urgonian cliff of the southern Vercors massif, French Alps. This event took place when the Vercors plateau was covered by snow. The unstable column was previously detected by observations on the development of a 30 m long fracture back on the plateau. Two aerial Lidar scans of the cliff were acquired before and after the failure, allowing the geometry of the column and of the broken plane to be determined. A temporary seismic array along with two extensometers was installed from July to November 2007. The seismic array consisted of 7 short period seismometers (1 three-components and 6 vertical-component). One vertical seismometer was installed on the column while the other 6 were deployed on the plateau with an array aperture of about 70 m. During the last two months of record, short period seismometers were replaced by 4.5 Hz geophones. The monitoring system recorded in a continuous mode (1000 Hz of frequency sampling) but it stopped to work two weeks before the fall, after the solar panels were covered by snow. During the running period, the seismic array recorded hundreds of local seismic events, from short (less than 0.5 s) impulsive signals to events with a long duration (a few tens of seconds). Our study was first focused on the dynamic response of the column and on the seismic noise frequency content. Fourier spectra of the seismic noise signals recorded on the column and the corresponding spectral ratios showed the presence of several resonance frequencies of the column. The first resonance frequency was measured at 3.6 Hz in July 2007 and it decreases regularly with time to reach 2.6 Hz two weeks before the fall. In parallel, extensometer measurements show that the fracture aperture increased with time during the same period. The dynamic response of a block which separates from a rock mass was 2D numerically modelled. Finite element computations showed that the progressive block decoupling, resulting from a crack propagation inside the mass, generates a decrease of the natural frequency, as it was measured on the site. These results highlight the interest to study the dynamic response of an unstable column for hazard assessment purposes. In a second phase, we studied the recorded impulsive signals in which we were able to identify P and S waves. Seismic experiments were performed in September 2008 on the plateau in order to constrain the ground velocity structure. Preliminary event location shows that the signal sources were located along the broken plane and probably result from micro-cracks along rock bridges.

Deposition and transport of Pseudomonas aeruginosa in porous media: lab-scale experiments and model analysis.

PubMed

Kwon, Kyu-Sang; Kim, Song-Bae; Choi, Nag-Choul; Kim, Dong-Ju; Lee, Soonjae; Lee, Sang-Hyup; Choi, Jae-Woo

2013-01-01

In this study, the deposition and transport of Pseudomonas aeruginosa on sandy porous materials have been investigated under static and dynamic flow conditions. For the static experiments, both equilibrium and kinetic batch tests were performed at a 1:3 and 3:1 soil:solution ratio. The batch data were analysed to quantify the deposition parameters under static conditions. Column tests were performed for dynamic flow experiments with KCl solution and bacteria suspended in (1) deionized water, (2) mineral salt medium (MSM) and (3) surfactant + MSM. The equilibrium distribution coefficient (K(d)) was larger at a 1:3 (2.43 mL g(-1)) than that at a 3:1 (0.28 mL g(-1)) soil:solution ratio. Kinetic batch experiments showed that the reversible deposition rate coefficient (k(att)) and the release rate coefficient (k(det)) at a soil:solution ratio of 3:1 were larger than those at a 1:3 ratio. Column experiments showed that an increase in ionic strength resulted in a decrease in peak concentration of bacteria, mass recovery and tailing of the bacterial breakthrough curve (BTC) and that the presence of surfactant enhanced the movement of bacteria through quartz sand, giving increased mass recovery and tailing. Deposition parameters under dynamic condition were determined by fitting BTCs to four different transport models, (1) kinetic reversible, (2) two-site, (3) kinetic irreversible and (4) kinetic reversible and irreversible models. Among these models, Model 4 was more suitable than the others since it includes the irreversible sorption term directly related to the mass loss of bacteria observed in the column experiment. Applicability of the parameters obtained from the batch experiments to simulate the column breakthrough data is evaluated.

Short- and Long-Term Outcomes of Student Field Research Experiences in Special Populations.

PubMed

Soliman, Amr S; Chamberlain, Robert M

2016-06-01

Global health education and training of biomedical students in international and minority health research is expending through U.S. academic institutions. This study addresses the short- and long-term outcomes of an NCI-funded R25 short-term summer field research training program. This program is designed for MPH and Ph.D. students in cancer epidemiology and related disciplines, in international and minority settings (special populations) in a recent 7-year period. Positive short-term outcome of 73 students was measured as publishing a manuscript from the field research data and having a job in special populations. Positive long-term outcome was measured as having a post-doc position, being in a doctoral program, and/or employment in special populations at least 3 years from finishing the program. Significant factors associated with both short- and long-term success included resourcefulness of the student and compatibility of personalities and interests between the student and the on-campus and off-campus mentors. Short-term-success of students who conducted international filed research was associated with visits of the on-campus mentor to the field site. Short-term success was also associated with extent of mentorship in the field site and with long-term success. Future studies should investigate how field research sites could enhance careers of students, appropriateness of the sites for specific training competencies, and how to maximize the learning experience of students in international and minority research sites.

Effect of Short-Term Hypergravity Treatment on Mouse 2-Cell Embryo Development

NASA Astrophysics Data System (ADS)

Ning, Li-Na; Lei, Xiao-Hua; Cao, Yu-Jing; Zhang, Yun-Fang; Cao, Zhong-Hong; Chen, Qi; Duan, En-Kui

2015-11-01

Though there are numerous biological experiments, which have been performed in a space environment, to study the physiological effect of space travel on living organisms, while the potential effect of weightlessness or short-term hypergravity on the reproductive system in most species, particularly in mammalian is still controversial and unclear. In our previous study, we investigated the effect of space microgravity on the development of mouse 4-cell embryos by using Chinese SJ-8. .Unexpectedly, we did not get any developed embryo during the space-flight. Considering that the process of space experiment is quite different from most experiments done on earth in several aspects such as, the vibration and short-term hypergravity during the rock launching and landing. Thus we want to know whether the short-term hypergravity produced by the launch process affect the early embryo development in mice, and howthe early embryos respond to the hypergravity. In present study, we are mimicking the short-term hypergravity during launch by using a centrifuge to investigate its influence on the development of early embryo (2-cell) in mice. We also examined the actin filament distribution in 2-cell embryos by immunostaining to test their potential capacity of development under short-term hypergravity exposure. Our results showed that most 2-cell embryos in the hypergravity exposure groups developed into blastocysts with normal morphology after 72h cultured in vitro, and there is no obvious difference in the development rate of blastocyst formation compared to the control. Moreover, there were no statistically significant differences in birth rates after oviduct transfer of 2-cell mouse embryos exposed on short-term hypergravity compared with 1 g condition. In addition, the well-organized actin distribution appeared in 2-cell embryos after exposed on hypergravity and also in the subsequent developmental blastocysts. Taken together, our data shows that short-term exposure in hypergravity conditions does not affect the normal development and actin filament structures of mouse embryos.

Direct and indirect effects of biochar on the mobility of metals and nutrients in contaminated soils: a two-column leaching experiment

NASA Astrophysics Data System (ADS)

Rees, Frédéric; Simonnot, Marie-Odile; Morel, Jean-Louis

2014-05-01

Biochar has been claimed to be not only a promising carbon sequestration or fertilizing agent in soils but also a high capacity sorbent, of particular interest for the management of contaminated soils. Several studies have described its positive effects on the mobility of different potentially toxic elements in soils, but many doubts remain about the underlying mechanisms. In particular, the distinction between the actual adsorption of elements on biochar and their biochar-induced retention on soil particles is often impossible to achieve. We studied here the dynamic interactions between one biochar produced at 450°C from a mix of hard wood and soft wood, and two soils contaminated by Cd, Pb and Zn which were sampled near a smelter and only differed from their pH. In order to distinguish between the actual immobilization of elements on biochar and their modified retention on soil particles, we developed a two-column leaching experiment using calcium nitrate as the initial leaching solution. The first column was filled with one of the two soils, and was linked in a closed loop with the second column containing a mass of pure biochar equivalent to 10% of the soil mass. The leaching solution circulated first in the soil column, then through the biochar column and again in the soil column and so on, so that it became progressively equilibrated with both soil and biochar. Each experiment lasted for 12 days at a flow rate of 1 mL/min. The pH and electrical conductivity of the leaching solution was continuously monitored at the outlet of the biochar column, and samples of the leaching solution were regularly taken for further analysis, both before and after having passed each of the columns. Our results show that the chemical equilibrium between soil and biochar was obtained in a short time for major elements such as Na, K and Mg, whereas for heavy metals and other elements as well as for pH and dissolved carbon, the equilibrium was still not reached at the end of the experiment. This observation highlights the slow, diffusive nature of biochar chemical interactions with the soil. The comparison of samples enabled us to quantify the immobilization of elements on biochar from its indirect effect on the retention capacity of the soil, mostly due to the increase of pH and the dynamics of inorganic and organic carbon in the solution. Altogether, these results provide new information about the complex effects of biochar on soil properties and about its efficiency in the context of soil remediation.

Short-term Action Intentions Overrule Long-Term Semantic Knowledge

ERIC Educational Resources Information Center

van Elk, M.; van Schie, H.T.; Bekkering, H.

2009-01-01

In the present study, we investigated whether the preparation of an unusual action with an object (e.g. bringing a cup towards the eye) could selectively overrule long-term semantic representations. In the first experiment it was found that unusual action intentions activated short-term semantic goal representations, rather than long-term…

Exposure to and recall of violence reduce short-term memory and cognitive control.

PubMed

Bogliacino, Francesco; Grimalda, Gianluca; Ortoleva, Pietro; Ring, Patrick

2017-08-08

Previous research has investigated the effects of violence and warfare on individuals' well-being, mental health, and individual prosociality and risk aversion. This study establishes the short- and long-term effects of exposure to violence on short-term memory and aspects of cognitive control. Short-term memory is the ability to store information. Cognitive control is the capacity to exert inhibition, working memory, and cognitive flexibility. Both have been shown to affect positively individual well-being and societal development. We sampled Colombian civilians who were exposed either to urban violence or to warfare more than a decade earlier. We assessed exposure to violence through either the urban district-level homicide rate or self-reported measures. Before undertaking cognitive tests, a randomly selected subset of our sample was asked to recall emotions of anxiety and fear connected to experiences of violence, whereas the rest recalled joyful or emotionally neutral experiences. We found that higher exposure to violence was associated with lower short-term memory abilities and lower cognitive control in the group recalling experiences of violence, whereas it had no effect in the other group. This finding demonstrates that exposure to violence, even if a decade earlier, can hamper cognitive functions, but only among individuals actively recalling emotional states linked with such experiences. A laboratory experiment conducted in Germany aimed to separate the effect of recalling violent events from the effect of emotions of fear and anxiety. Both factors had significant negative effects on cognitive functions and appeared to be independent from each other.

Exposure to and recall of violence reduce short-term memory and cognitive control

PubMed Central

Bogliacino, Francesco; Ortoleva, Pietro; Ring, Patrick

2017-01-01

Previous research has investigated the effects of violence and warfare on individuals' well-being, mental health, and individual prosociality and risk aversion. This study establishes the short- and long-term effects of exposure to violence on short-term memory and aspects of cognitive control. Short-term memory is the ability to store information. Cognitive control is the capacity to exert inhibition, working memory, and cognitive flexibility. Both have been shown to affect positively individual well-being and societal development. We sampled Colombian civilians who were exposed either to urban violence or to warfare more than a decade earlier. We assessed exposure to violence through either the urban district-level homicide rate or self-reported measures. Before undertaking cognitive tests, a randomly selected subset of our sample was asked to recall emotions of anxiety and fear connected to experiences of violence, whereas the rest recalled joyful or emotionally neutral experiences. We found that higher exposure to violence was associated with lower short-term memory abilities and lower cognitive control in the group recalling experiences of violence, whereas it had no effect in the other group. This finding demonstrates that exposure to violence, even if a decade earlier, can hamper cognitive functions, but only among individuals actively recalling emotional states linked with such experiences. A laboratory experiment conducted in Germany aimed to separate the effect of recalling violent events from the effect of emotions of fear and anxiety. Both factors had significant negative effects on cognitive functions and appeared to be independent from each other. PMID:28739904

A first look at the turnover dynamics of low molecular weight organic carbon in shallow and deep soils of coastal prairie grassland ecosystem.

NASA Astrophysics Data System (ADS)

Mcfarland, J. W.; Lawrence, C. R.; Creamer, C.; Conaway, C. H.; Haw, M.; Waldrop, M. P.

2016-12-01

The functional importance of low molecular weight organic compounds (LMWOC) is in disproportion to their abundance within soil organic carbon (SOC) pools. LMWOC are critical in driving microbial metabolism, though microbial utilization is likely dependent on C chemistry. In this study, we examined the fate of two important, often plant-derived, components of soluble SOC: sugars and carboxylic acids, through an extended soil profile. Our objective was to evaluate the short-term (9 d) and long-term (16 mo) turnover dynamics of LMWOC under varying physical, biological, and chemical conditions through the soil column. Our study area is a coastal prairie near Santa Cruz, CA; soils are classified as fine-loamy, mixed thermic typic Argixerolls. The long-term component of this study was conducted in situ and replicated in the laboratory to quantify the short-term dynamics. We injected 13C-labeled glucose (GLU), 13C-labeled oxalic acid (OA), or deionized water into the A, B (argillic), and B/C (mottled) horizons at depths of 25, 75, and 125 cm, respectively. We sampled soil gas for 13CO2 intensively in the lab and at increasingly graduated intervals in the field. At the conclusion of each experiment, soils were harvested to assess total recovery of 13C in soil pools. Measures of extractable C indicated a significant priming effect in the A horizon, and an increase in microbial biomass C (MBC) in the argillic horizon in response to GLU and OA. In all instances, residence time was lower for GLU than OA and increased with depth for both substrates. In the short-term OA- C was mineralized to a greater degree than GLU- C in the A and argillic horizons, but in the deepest (mottled) soil horizon recovery of OA- C was substantially higher, and likely resulted from enhanced organo-metal complexation. Dissolved Al3+, which forms strong aqueous complexes with OA, may limit the availability of OA at depth compared to shallower soils. Long-term recovery favored GLU- C, which increased with depth. GLU contains no significant functional groups for adsorption to the mineral phase, but immobilization within MBC was comparatively high, which suggests long-term retention of GLU-C is linked to mineral interaction with microbial residues following turnover.

Statistical mechanics of neocortical interactions: A scaling paradigm applied to electroencephalography

NASA Astrophysics Data System (ADS)

Ingber, Lester

1991-09-01

A series of papers has developed a statistical mechanics of neocortical interactions (SMNI), deriving aggregate behavior of experimentally observed columns of neurons from statistical electrical-chemical properties of synaptic interactions. While not useful to yield insights at the single-neuron level, SMNI has demonstrated its capability in describing large-scale properties of short-term memory and electroencephalographic (EEG) systematics. The necessity of including nonlinear and stochastic structures in this development has been stressed. In this paper, a more stringent test is placed on SMNI: The algebraic and numerical algorithms previously developed in this and similar systems are brought to bear to fit large sets of EEG and evoked-potential data being collected to investigate genetic predispositions to alcoholism and to extract brain ``signatures'' of short-term memory. Using the numerical algorithm of very fast simulated reannealing, it is demonstrated that SMNI can indeed fit these data within experimentally observed ranges of its underlying neuronal-synaptic parameters, and the quantitative modeling results are used to examine physical neocortical mechanisms to discriminate high-risk and low-risk populations genetically predisposed to alcoholism. Since this study is a control to span relatively long time epochs, similar to earlier attempts to establish such correlations, this discrimination is inconclusive because of other neuronal activity which can mask such effects. However, the SMNI model is shown to be consistent with EEG data during selective attention tasks and with neocortical mechanisms describing short-term memory previously published using this approach. This paper explicitly identifies similar nonlinear stochastic mechanisms of interaction at the microscopic-neuronal, mesoscopic-columnar, and macroscopic-regional scales of neocortical interactions. These results give strong quantitative support for an accurate intuitive picture, portraying neocortical interactions as having common algebraic or physics mechanisms that scale across quite disparate spatial scales and functional or behavioral phenomena, i.e., describing interactions among neurons, columns of neurons, and regional masses of neurons.

Impacts of 120 years of fertilizer addition on a temperate grassland ecosystem

PubMed Central

Kidd, Jonathan; Manning, Peter; Simkin, Janet; Peacock, Simon; Stockdale, Elizabeth

2017-01-01

The widespread application of fertilizers has greatly influenced many processes and properties of agroecosystems, and agricultural fertilization is expected to increase even further in the future. To date, most research on fertilizer impacts has used short-term studies, which may be unrepresentative of long-term responses, thus hindering our capacity to predict long-term impacts. Here, we examined the effects of long-term fertilizer addition on key ecosystem properties in a long-term grassland experiment (Palace Leas Hay Meadow) in which farmyard manure (FYM) and inorganic fertilizer treatments have been applied consistently for 120 years in order to characterize the experimental site more fully and compare ecosystem responses with those observed at other long-term and short-term experiments. FYM inputs increased soil organic carbon (SOC) stocks, hay yield, nutrient availability and acted as a buffer against soil acidification (>pH 5). In contrast, N-containing inorganic fertilizers strongly acidified the soil (

First Directly Retrieved Global Distribution of Tropospheric Column Ozone from GOME: Comparison with the GEOS-CHEM Model

NASA Technical Reports Server (NTRS)

Liu, Xiong; Chance, Kelly; Sioris, Christopher E.; Kurosu, Thomas P.; Spurr, Robert J. D.; Martin, Randall V.; Fu, Tzung-May; Logan, Jennifer A.; Jacob, Daniel J.; Palmer, Paul I.;

Adolescent Development of Global Competencies through a Short-Term International Study-Travel Experience to China

ERIC Educational Resources Information Center

Gould, Rachel Zucker

2012-01-01

The capacity of adolescents to develop global competencies was examined by collecting and analyzing data from 62 student-travelers before, during, and after a short-term study-travel experience to China. The Global Perspectives Inventory was used to compare the student-travelers' perspectives before and after travel with a comparison group of 60…

How to Say No: Single- and Dual-Process Theories of Short-Term Recognition Tested on Negative Probes

ERIC Educational Resources Information Center

Oberauer, Klaus

2008-01-01

Three experiments with short-term recognition tasks are reported. In Experiments 1 and 2, participants decided whether a probe matched a list item specified by its spatial location. Items presented at study in a different location (intrusion probes) had to be rejected. Serial position curves of positive, new, and intrusion probes over the probed…

Short Term International Study for Teachers as a Form of Experiential Learning: A Case Study of American Educators in Turkey

ERIC Educational Resources Information Center

Berk, Zulfikar

2017-01-01

This dissertation is a case study of the experiences and perspectives of nine US teachers who participated in a short-term international study tour to Turkey, from the theoretical perspectives of global education and experiential learning. It examines how that experience shaped the teachers' understandings of global dynamics, cultural differences…

Identity modulates short-term memory for facial emotion.

PubMed

Galster, Murray; Kahana, Michael J; Wilson, Hugh R; Sekuler, Robert

2009-12-01

For some time, the relationship between processing of facial expression and facial identity has been in dispute. Using realistic synthetic faces, we reexamined this relationship for both perception and short-term memory. In Experiment 1, subjects tried to identify whether the emotional expression on a probe stimulus face matched the emotional expression on either of two remembered faces that they had just seen. The results showed that identity strongly influenced recognition short-term memory for emotional expression. In Experiment 2, subjects' similarity/dissimilarity judgments were transformed by multidimensional scaling (MDS) into a 2-D description of the faces' perceptual representations. Distances among stimuli in the MDS representation, which showed a strong linkage of emotional expression and facial identity, were good predictors of correct and false recognitions obtained previously in Experiment 1. The convergence of the results from Experiments 1 and 2 suggests that the overall structure and configuration of faces' perceptual representations may parallel their representation in short-term memory and that facial identity modulates the representation of facial emotion, both in perception and in memory. The stimuli from this study may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental.

Identity modulates short-term memory for facial emotion

PubMed Central

Galster, Murray; Kahana, Michael J.; Wilson, Hugh R.; Sekuler, Robert

2010-01-01

For some time, the relationship between processing of facial expression and facial identity has been in dispute. Using realistic synthetic faces, we reexamined this relationship for both perception and short-term memory. In Experiment 1, subjects tried to identify whether the emotional expression on a probe stimulus face matched the emotional expression on either of two remembered faces that they had just seen. The results showed that identity strongly influenced recognition short-term memory for emotional expression. In Experiment 2, subjects’ similarity/dissimilarity judgments were transformed by multidimensional scaling (MDS) into a 2-D description of the faces’ perceptual representations. Distances among stimuli in the MDS representation, which showed a strong linkage of emotional expression and facial identity, were good predictors of correct and false recognitions obtained previously in Experiment 1. The convergence of the results from Experiments 1 and 2 suggests that the overall structure and configuration of faces’ perceptual representations may parallel their representation in short-term memory and that facial identity modulates the representation of facial emotion, both in perception and in memory. The stimuli from this study may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental. PMID:19897794

Shear Performance of Horizontal Joints in Short Precast Concrete Columns with Sleeve Grouted Connections under Cyclic Loading

PubMed Central

Liu, Bingyu; Chen, Jiang; Zhang, Yiping

2016-01-01

In this study, two short precast concrete columns and two cast-in-situ concrete columns were tested under cyclic loads. It was shown that the sleeve grouted connection was equivalent to the cast-in-situ connections for short columns when the axial compression ratio was 0.6. In order to determine the influence of the axial compression ratio and the shear-span ratio on the shear capacity of the horizontal joint, a FE model was established and verified. The analysis showed that the axial compression ratio is advantageous to the joint and the shear capacity of the horizontal joint increases with increase of the shear-span ratio. Based on the results, the methods used to estimate the shear capacity of horizontal joints in the Chinese Specification and the Japanese Guidelines are discussed and it was found that both overestimated the shear capacity of the horizontal joint. In addition, the Chinese Specification failed to consider the influence of the shear-span ratio. PMID:27861493

Effects of Cabin Upsets on Adsorption Columns for Air Revitalization

NASA Technical Reports Server (NTRS)

LeVan, Douglas

1999-01-01

The National Aeronautics and Space Administration (NASA) utilizes adsorption technology as part of contaminant removal systems designed for long term missions. A variety of trace contaminants can be effectively removed from gas streams by adsorption onto activated carbon. An activated carbon adsorption column meets NASA's requirements of a lightweight and efficient means of controlling trace contaminant levels aboard spacecraft and space stations. The activated carbon bed is part of the Trace Contaminant Control System (TCCS) which is utilized to purify the cabin atmosphere. TCCS designs oversize the adsorption columns to account for irregular fluctuations in cabin atmospheric conditions. Variations in the cabin atmosphere include changes in contaminant concentrations, temperature, and relative humidity. Excessively large deviations from typical conditions can result from unusual crew activity, equipment malfunctions, or even fires. The research carried out under this award focussed in detail on the effects of cabin upsets on the performance of activated carbon adsorption columns. Both experiments and modeling were performed with an emphasis on the roll of a change in relative humidity on adsorption of trace contaminants. A flow through fixed-bed apparatus was constructed at the NASA Ames Research Center, and experiments were performed there. Modeling work was performed at the University of Virginia.

How high is visual short-term memory capacity for object layout?

PubMed

Sanocki, Thomas; Sellers, Eric; Mittelstadt, Jeff; Sulman, Noah

2010-05-01

Previous research measuring visual short-term memory (VSTM) suggests that the capacity for representing the layout of objects is fairly high. In four experiments, we further explored the capacity of VSTM for layout of objects, using the change detection method. In Experiment 1, participants retained most of the elements in displays of 4 to 8 elements. In Experiments 2 and 3, with up to 20 elements, participants retained many of them, reaching a capacity of 13.4 stimulus elements. In Experiment 4, participants retained much of a complex naturalistic scene. In most cases, increasing display size caused only modest reductions in performance, consistent with the idea of configural, variable-resolution grouping. The results indicate that participants can retain a substantial amount of scene layout information (objects and locations) in short-term memory. We propose that this is a case of remote visual understanding, where observers' ability to integrate information from a scene is paramount.

Reconstruction of daily solar UV irradiation from 1893 to 2002 in Potsdam, Germany

NASA Astrophysics Data System (ADS)

Junk, Jürgen; Feister, Uwe; Helbig, Alfred

2007-08-01

Long-term records of solar UV radiation reaching the Earth’s surface are scarce. Radiative transfer calculations and statistical models are two options used to reconstruct decadal changes in solar UV radiation from long-term records of measured atmospheric parameters that contain information on the effect of clouds, atmospheric aerosols and ground albedo on UV radiation. Based on earlier studies, where the long-term variation of daily solar UV irradiation was derived from measured global and diffuse irradiation as well as atmospheric ozone by a non-linear regression method [Feister et al. (2002) Photochem Photobiol 76:281 293], we present another approach for the reconstruction of time series of solar UV radiation. An artificial neural network (ANN) was trained with measurements of solar UV irradiation taken at the Meteorological Observatory in Potsdam, Germany, as well as measured parameters with long-term records such as global and diffuse radiation, sunshine duration, horizontal visibility and column ozone. This study is focussed on the reconstruction of daily broad-band UV-B (280 315 nm), UV-A (315 400 nm) and erythemal UV irradiation (ER). Due to the rapid changes in cloudiness at mid-latitude sites, solar UV irradiance exhibits appreciable short-term variability. One of the main advantages of the statistical method is that it uses doses of highly variable input parameters calculated from individual spot measurements taken at short time intervals, which thus do represent the short-term variability of solar irradiance.

Direct Demonstration of the Greenhouse Effect

NASA Astrophysics Data System (ADS)

Jaffe, D. A.; Malashanka, S.; Call, K.; Bernays, N.

2012-12-01

Consider these three "theories:" climate change, evolution, and gravity. Why are two of them hotly debated by non-scientists, but not gravity? In part, the answer is that climate change and evolution are more complex processes and not readily observable over short time scales to most people. In contrast, the "theory of gravity" is tested every day by billions of people world-wide and is therefore not challenged. While there are numerous "demonstrations" of the greenhouse effect available online, unfortunately, many of them are based on poor understanding of the physical principles involved. For this reason, we sought to develop simple and direct experiments that would demonstrate aspects of the greenhouse effect that would be suitable for museums, K-12, and/or college classrooms. We will describe two experiments. In the first, we use a simple plexiglass tube, approximately 12 cm long, with IR transparent windows. The tube is first filled with dry nitrogen and exposed to an IR heat lamp. Following this, the tube is filled with pure, dry CO2. Both tubes warm up, but the tube filled with CO2 ends up about 0.7 degrees C warmer. It is useful to compare this 12 cm column of CO2 to the column in the earth's atmosphere, which is equivalent to approximately 2.7 meters of pure CO2. This demonstration would be suitable for museum exhibits to demonstrate the physical basis of CO2 heating in the atmosphere. In the second experiment, we use FTIR spectroscopy to quantify the CO2 content of ambient air and indoor/classroom air. For this experiment, we use a commercial standard of 350 ppm CO2 to calibrate the absorption features. Once the CO2 content of ambient air is found, it is useful for students to compare their observed value to background data (e.g. NOAA site in Hawaii) and/or the "Keeling Curve". This leads into a discussion on causes for local variations and the long-term trends. This experiment is currently used in our general chemistry class but could be used in many other science classes. Both of the above experiments should lead to a greater understanding of the scientific basis for the greenhouse effect.

Impact of Flow-Dependent Error Correlations and Tropospheric Chemistry on Assimilated Ozone

NASA Technical Reports Server (NTRS)

Wargan, K.; Stajner, I.; Hayashi, H.; Pawson, S.; Jones, D. B. A.

2003-01-01

The presentation compares different versions of a global three-dimensional ozone data assimilation system developed at NASA's Data Assimilation Office. The Solar Backscatter Ultraviolet/2 (SBUV/2) total and partial ozone column retrievals are the sole data assimilated in all of the experiments presented. We study the impact of changing the forecast error covariance model from a version assuming static correlations with a one that captures a short-term Lagrangian evolution of those correlations. This is further combined with a study of the impact of neglecting the tropospheric ozone production, loss and dry deposition rates, which are obtained from the Harvard GEOS-CHEM model. We compare statistical characteristics of the assimilated data and the results of validation against independent observations, obtained from WMO balloon-borne sondes and the Polar Ozone and Aerosol Measurement (POAM) III instrument. Experiments show that allowing forecast error correlations to evolve with the flow results in positive impact on assimilated ozone within the regions where data were not assimilated, particularly at high latitudes in both hemispheres. On the other hand, the main sensitivity to tropospheric chemistry is in the Tropics and sub-Tropics. The best agreement between the assimilated ozone and the in-situ sonde data is in the experiment using both flow-dependent error covariances and tropospheric chemistry.

Behaviour of axially and eccentrically loaded short columns reinforced with GFRP bars

NASA Astrophysics Data System (ADS)

Sreenath, S.; Balaji, S.; Saravana Raja Mohan, K.

2017-07-01

The corrosion of steel reinforcing bars is a predominant factor in limiting the life expectancy of Reinforced Cement Concrete (RCC) structures. Corrosion resistant Fibre Reinforced Polymer (FRP) bars can be an effective alternative to steel bars in this context. Recent investigations reported the flexural behaviour of RCC beams reinforced with Glass Fibre Reinforced Polymer (GFRP) bars. This study is meant to investigate the suitability of Sand Coated GFRP reinforcement bars in short square columns which when loaded axially and loaded with a minimum eccentricity. Standard tests to assess mechanical properties of GFRP bars and pullout test to quantify the bond strength between the bars and concrete were conducted. GFRP reinforced column specimens with a cross-sectional dimension of 100mm X 100mm and of length 1000mm were cast and tested under axial and eccentric loading. The assessed load carrying capacity was compared with that of conventional steel reinforced columns of the same size. The yield load and ultimate load at failure withstood by the steel reinforced columns were considerably more than that of GFRP reinforced columns. The energy absorption capacity of GFRP reinforced columns was also poor compared to steel reinforced columns. Both the columns exhibited nearly the same ductile behaviour. Hence GFRP reinforcements are not recommendable for compression members.

Fraxel laser indications and long-term follow-up.

PubMed

Tanzi, Elizabeth L; Wanitphakdeedecha, Rungsima; Alster, Tina S

2008-01-01

Fractional photothermolysis, based on creating spatially precise microscopic thermal wounds, is performed using a 1550-nm erbium fiber laser that targets water-containing tissue to effect the photocoagulation of narrow, sharply defined columns of skin known as microscopic thermal zones. According to the authors, Fraxel resurfacing has been shown to be both safe and effective for facial and nonfacial photodamage, atrophic acne scars, hypopigmented scars, and dyspigmentation. Because only a fraction of the skin is treated during a single session, a series (typically 3 to 6 treatments) of fractional resurfacing at 2- to 4-week intervals is required for the best clinical improvement. It is the authors' experience that a series of Fraxel treatments can achieve a similar clinical result for atrophic scars compared with traditional ablative laser skin resurfacing. However, the improvement seen after a series of Fraxel treatments for perioral laxity and rhytides often falls short of the impressive results that can be achieved with ablative laser skin resurfacing.

Advances in SAW gas sensors based on the condensate-adsorption effect.

PubMed

Liu, Jiuling; Wang, Wen; Li, Shunzhou; Liu, Minghua; He, Shitang

2011-01-01

A surface-acoustic-wave (SAW) gas sensor with a low detection limit and fast response for volatile organic compounds (VOCs) based on the condensate-adsorption effect detection is developed. In this sensor a gas chromatography (GC) column acts as the separator element and a dual-resonator oscillator acts as the detector element. Regarding the surface effective permittivity method, the response mechanism analysis, which relates the condensate-adsorption effect, is performed, leading to the sensor performance prediction prior to fabrication. New designs of SAW resonators, which act as feedback of the oscillator, are devised in order to decrease the insertion loss and to achieve single-mode control, resulting in superior frequency stability of the oscillator. Based on the new phase modulation approach, excellent short-term frequency stability (±3 Hz/s) is achieved with the SAW oscillator by using the 500 MHz dual-port resonator as feedback element. In a sensor experiment investigating formaldehyde detection, the implemented SAW gas sensor exhibits an excellent threshold detection limit as low as 0.38 pg.

Effects of age, gender, and stimulus presentation period on visual short-term memory.

PubMed

Kunimi, Mitsunobu

2016-01-01

This study focused on age-related changes in visual short-term memory using visual stimuli that did not allow verbal encoding. Experiment 1 examined the effects of age and the length of the stimulus presentation period on visual short-term memory function. Experiment 2 examined the effects of age, gender, and the length of the stimulus presentation period on visual short-term memory function. The worst memory performance and the largest performance difference between the age groups were observed in the shortest stimulus presentation period conditions. The performance difference between the age groups became smaller as the stimulus presentation period became longer; however, it did not completely disappear. Although gender did not have a significant effect on d' regardless of the presentation period in the young group, a significant gender-based difference was observed for stimulus presentation periods of 500 ms and 1,000 ms in the older group. This study indicates that the decline in visual short-term memory observed in the older group is due to the interaction of several factors.

Decay uncovered in nonverbal short-term memory.

PubMed

Mercer, Tom; McKeown, Denis

2014-02-01

Decay theory posits that memory traces gradually fade away over the passage of time unless they are actively rehearsed. Much recent work exploring verbal short-term memory has challenged this theory, but there does appear to be evidence for trace decay in nonverbal auditory short-term memory. Numerous discrimination studies have reported a performance decline as the interval separating two tones is increased, consistent with a decay process. However, most of this tone comparison research can be explained in other ways, without reference to decay, and these alternative accounts were tested in the present study. In Experiment 1, signals were employed toward the end of extended retention intervals to ensure that listeners were alert to the presence and frequency content of the memoranda. In Experiment 2, a mask stimulus was employed in an attempt to distinguish between a highly detailed sensory trace and a longer-lasting short-term memory, and the distinctiveness of the stimuli was varied. Despite these precautions, slow-acting trace decay was observed. It therefore appears that the mere passage of time can lead to forgetting in some forms of short-term memory.

Influence of the presence of PAHs and coal tar on naphthalene sorption in soils

NASA Astrophysics Data System (ADS)

Bayard, Rémy; Barna, Ligia; Mahjoub, Borhane; Gourdon, Rémy

2000-11-01

The mobility of the most water-soluble polynuclear aromatic hydrocarbons (PAHs) such as naphthalene in contaminated soils from manufactured gas plant (MGP) sites or other similar sites is influenced not only by the naturally occurring soil organic matter (SOM) but also, and in many cases mostly, by the nature and concentration of coal tar xenobiotic organic matter (XOM) and other PAH molecules present in the medium under various physical states. The objective of the present study was to quantify the effects of these factors using batch experiments, in order to simulate naphthalene transport in soil-tar-water systems using column experiments. Naphthalene sorption was studied in the presence of (i) solid coal tar particles, (ii) phenanthrene supplied as pure crystals, in the aqueous solution or already sorbed onto the soil, (iii) fluoranthene as pure crystals, and (iv) an aqueous solution of organic molecules extracted from a liquid tar. All experiments were conducted under abiotic conditions using short naphthalene/sorbent contact times of 24-60 h. Although these tests do not reflect true equilibrium conditions which usually take more time to establish, they were used to segregate relatively rapid sorption phenomena ("pseudo equilibrium") from slow sorption and other aging phenomena. For longer contact times, published data have shown that experimental biases due to progressive changes in the characteristics of the soil and the solution may drastically modify the affinity of the solutes for the soil. Slow diffusion in the microporosity and in dense organic phases may also become significant over the long term, along with some irreversible aging phenomena which have not been addressed in this work. Results showed that PAHs had no effect on naphthalene sorption when present in the aqueous solution or as pure crystals, due to their low solubility in water. Adsorbed phenanthrene was found to reduce naphthalene adsorption only when present at relatively high concentrations (about 120 mg/kg) in the soil. In contrast, experiments carried out with coal tar particles revealed a significant effect. Naphthalene sorption appeared to be proportional to the amount of coal tar added to the sand or soil, and a much higher affinity of naphthalene for XOM ( Koc above 2000 cm 3/g) than SOM ( Koc around 300 cm 3/g) was observed. Naphthalene transport in the columns of sand or soil spiked with coal tar particles was simulated very satisfactorily with a dual double-domain model. Around 90% of naphthalene retention by coal tar was found to occur within the organic phase, suggesting a phase partition process which may be explained by the amorphous nature of the XOM and its extreme affinity for naphthalene. For SOM, however, which is present as porous microaggregates of clay and humic substances, with less affinity for naphthalene, only 1/3 of naphthalene retention was found to occur within the organic phase, underlining the significant role of surface adsorption in the short term behavior of naphthalene in soil. For longer contact times, the model simulations proposed in the present study should be coupled to slow sorption, aging and biodegradation models to describe long-term behavior of naphthalene in soil-tar-water systems.

Short-Term Memory for Temporal Intervals: Contrasting Explanations of the Choose-Short Effect in Pigeons

ERIC Educational Resources Information Center

Pinto, Carlos; Machado, Armando

2011-01-01

To better understand short-term memory for temporal intervals, we re-examined the choose-short effect. In Experiment 1, to contrast the predictions of two models of this effect, the subjective shortening and the coding models, pigeons were exposed to a delayed matching-to-sample task with three sample durations (2, 6 and 18 s) and retention…

Does precision decrease with set size?

PubMed Central

Mazyar, Helga; van den Berg, Ronald; Ma, Wei Ji

2012-01-01

The brain encodes visual information with limited precision. Contradictory evidence exists as to whether the precision with which an item is encoded depends on the number of stimuli in a display (set size). Some studies have found evidence that precision decreases with set size, but others have reported constant precision. These groups of studies differed in two ways. The studies that reported a decrease used displays with heterogeneous stimuli and tasks with a short-term memory component, while the ones that reported constancy used homogeneous stimuli and tasks that did not require short-term memory. To disentangle the effects of heterogeneity and short-memory involvement, we conducted two main experiments. In Experiment 1, stimuli were heterogeneous, and we compared a condition in which target identity was revealed before the stimulus display with one in which it was revealed afterward. In Experiment 2, target identity was fixed, and we compared heterogeneous and homogeneous distractor conditions. In both experiments, we compared an optimal-observer model in which precision is constant with set size with one in which it depends on set size. We found that precision decreases with set size when the distractors are heterogeneous, regardless of whether short-term memory is involved, but not when it is homogeneous. This suggests that heterogeneity, not short-term memory, is the critical factor. In addition, we found that precision exhibits variability across items and trials, which may partly be caused by attentional fluctuations. PMID:22685337

The Relationship between Semantic Short-Term Memory and Immediate Serial Recall of Known and Unknown Words and Nonwords: Data from Two Chinese Individuals with Aphasia

ERIC Educational Resources Information Center

Wong, Winsy; Low, Sam-Po

2008-01-01

The present study investigated verbal recall of semantically preserved and degraded words and nonwords by taking into consideration the status of one's semantic short-term memory (STM). Two experiments were conducted on 2 Chinese individuals with aphasia. The first experiment showed that they had largely preserved phonological processing abilities…

Contralateral Cortical Organisation of Information in Visual Short-Term Memory: Evidence from Lateralized Brain Activity during Retrieval

ERIC Educational Resources Information Center

Fortier-Gauthier, Ulysse; Moffat, Nicolas; Dell'Acqua, Robert; McDonald, John J.; Jolicoeur, Pierre

2012-01-01

We studied brain activity during retention and retrieval phases of two visual short-term memory (VSTM) experiments. Experiment 1 used a balanced memory array, with one color stimulus in each hemifield, followed by a retention interval and a central probe, at the fixation point that designated the target stimulus in memory about which to make a…

Long-term flow-through column experiments and their relevance to natural granitoid weathering rates

USGS Publications Warehouse

White, Arthur F.; Schulz, Marjorie S.; Lawrence, Corey R.; Vivit, Davison V.; Stonestrom, David A.

2017-01-01

Four pairs of fresh and partly-weathered granitoids, obtained from well-characterized watersheds—Merced River, CA, USA; Panola, GA, USA; Loch Vale, CO, USA, and Rio Icacos, Puerto Rico—were reacted in columns under ambient laboratory conditions for 13.8 yrs, the longest running experimental weathering study to date. Low total column mass losses (<1 wt. %), correlated with the absence of pitting or surface roughening of primary silicate grains. BET surface area (SBET) increased, primarily due to Fe-oxyhydroxide precipitation. Surface areas returned to within factors of 2 to 3 of their original values after dithionite extraction. Miscible displacement experiments indicated homogeneous plug flow with negligible immobile water, commonly cited for column experiments. Fresh granitoid effluent solute concentrations initially declined rapidly, followed by much slower decreases over the next decade. Weathered granitoid effluent concentrations increased modestly over the same time period, indicating losses of natural Fe-oxide and/or clay coatings and the increased exposure of primary mineral surfaces. Corresponding (fresh and weathered) elemental effluent concentrations trended toward convergence during the last decade of reaction. NETPATH/PHREEQC code simulations indicated non-stoichiometric dissolution involving Ca release from disseminated calcite and excess K release from interlayer biotite. Effluent 87Sr/85Sr ratios reflected a progressive weathering sequence beginning and ending with 87Sr/85Sr values of plagioclase with an additional calcite input and a radiogenic biotite excursion proportional to the granitoid ages.Effluents became thermodynamically saturated with goethite and gibbsite, slightly under-saturated with kaolinite and strongly under-saturated with plagioclase, consistent with kinetically-limited weathering in which solutes such as Na varied with column flow rates. Effluent Na concentrations showed no clear trend with time during the last decade of reaction (fresh granitoids) or increased slowly with time (weathered granitoids). Analysis of cumulative Na release indicated that plagioclase dissolution achieved steady state in 3 of the 4 fresh granitoids during the last decade of reaction. Surface-area normalized plagioclase dissolution rates exhibited a narrow range (0.95 to 1.26 10-13 moles m-2 s-1), in spite of significant stoichiometric differences (An0.21 to An0.50). Rates were an order of magnitude slower than previously reported in shorter duration experiments but generally 2 to 3 orders of magnitude faster than corresponding natural analogs. CrunchFlow simulations indicated that more than a hundredfold decrease in column flow rates would be required to produce near-saturation reaction affinities that would start to slow plagioclase weathering to real-world levels. Extending simulations to approximate long term weathering in naturally weathered profiles required additional decreases in the intrinsic plagioclase dissolution and kaolinite precipitation rates and relatively large decreases in the fluid flow rate, implying that exposure to reactive mineral surfaces is significantly limited in the natural environment compared to column experiments.

Long-term flow-through column experiments and their relevance to natural granitoid weathering rates

NASA Astrophysics Data System (ADS)

White, Art F.; Schulz, Marjorie S.; Lawrence, Corey R.; Vivit, Davison V.; Stonestrom, David A.

2017-04-01

Four pairs of fresh and partly-weathered granitoids, obtained from well-characterized watersheds-Merced River, CA, USA; Panola, GA, USA; Loch Vale, CO, USA, and Rio Icacos, Puerto Rico-were reacted in columns under ambient laboratory conditions for 13.8 yrs, the longest running experimental weathering study to date. Low total column mass losses (<1 wt.%), correlated with the absence of pitting or surface roughening of primary silicate grains. BET surface area (SBET) increased, primarily due to Fe-oxyhydroxide precipitation. Surface areas returned to within factors of 2-3 of their original values after dithionite extraction. Miscible displacement experiments indicated homogeneous plug flow with negligible immobile water, commonly cited for column experiments. Fresh granitoid effluent solute concentrations initially declined rapidly, followed by much slower decreases over the next decade. Weathered granitoid effluent concentrations increased modestly over the same time period, indicating losses of natural Fe-oxide and/or clay coatings and the increased exposure of primary mineral surfaces. Corresponding (fresh and weathered) elemental effluent concentrations trended toward convergence during the last decade of reaction. NETPATH/PHREEQC code simulations indicated non-stoichiometric dissolution involving Ca release from disseminated calcite and excess K release from interlayer biotite. Effluent 87Sr/85Sr ratios reflected a progressive weathering sequence beginning and ending with 87Sr/85Sr values of plagioclase with an additional calcite input and a radiogenic biotite excursion proportional to the granitoid ages. Effluents became thermodynamically saturated with goethite and gibbsite, slightly under-saturated with kaolinite and strongly under-saturated with plagioclase, consistent with kinetically-limited weathering in which solutes such as Na varied with column flow rates. Effluent Na concentrations showed no clear trend with time during the last decade of reaction (fresh granitoids) or increased slowly with time (weathered granitoids). Analysis of cumulative Na release indicated that plagioclase dissolution achieved steady state in 3 of the 4 fresh granitoids during the last decade of reaction. Surface-area normalized plagioclase dissolution rates exhibited a narrow range (0.95-1.26 10-13 moles m-2 s-1), in spite of significant stoichiometric differences (An0.21 to An0.50). Rates were an order of magnitude slower than previously reported in shorter duration experiments but generally 2-3 orders of magnitude faster than corresponding natural analogs. CrunchFlow simulations indicated that more than a hundredfold decrease in column flow rates would be required to produce near-saturation reaction affinities that would start to slow plagioclase weathering to real-world levels. Extending simulations to approximate long term weathering in naturally weathered profiles required additional decreases in the intrinsic plagioclase dissolution and kaolinite precipitation rates and relatively large decreases in the fluid flow rate, implying that exposure to reactive mineral surfaces is significantly limited in the natural environment compared to column experiments.

Mitigation of solvent interference using a short packed column prior to ion mobility spectrometry.

PubMed

Jafari, Mohammad T; Saraji, Mohammad; Mossaddegh, Mehdi

2017-05-15

This paper introduces a novel approach to overcome the solvent interference in corona discharge-ion mobility spectrometry (CD-IMS) based on the time-resolved signals of the solvent and the analyte. To that end, a short Teflon tube was filled with a low amount of squalene or OV-1, which was prepared and located between the injection port and the entrance of the CD-IMS cell. Through this procedure, a sufficient delay (~5s) was obtained between the introduction of the solvent and the analyte into the reaction region of IMS. This resulted in removing the proton by solvent molecules, as well as increasing the effective collision during the analyte ionization, thereby providing an analysis with more sensitivity, accuracy, and precision. To show the column efficiency, ethion and diazinon (organophosphorus pesticides) were selected as the test compounds and their solutions were analyzed by the proposed method. The amount of sorbent, carrier gas flow rate, and the sorbent temperature affecting the sorbent efficiency were optimized by employing the response surface methodology and the central composite design. The proposed method was exhaustively validated in terms of sensitivity, linearity, and repeatability. In particular, the feasibility of direct injection was successfully verified by the satisfactory results, as compared with those achieved without the prior column. The methodology used in this study is very simple and inexpensive, which can overcome the solvent interference when a solution is directly injected into the CD-IMS. Copyright © 2017 Elsevier B.V. All rights reserved.

Reversed-phase liquid chromatography column testing: robustness study of the test.

PubMed

Le Mapihan, K; Vial, J; Jardy, A

2004-12-24

Choosing the right RPLC column for an actual separation among the more than 600 commercially available ones still represents a real challenge for the analyst particularly when basic solutes are involved. Many tests dedicated to the characterization and the classification of stationary phases have been proposed in the literature and some of them highlighted the need of a better understanding of retention properties to lead to a rational choice of columns. However, unlike classical chromatographic methods, the problem of their robustness evaluation has often been left unaddressed. In the present study, we present a robustness study that was applied to the chromatographic testing procedure we had developed and optimized previously. A design of experiment (DoE) approach was implemented. Four factors, previously identified as potentially influent, were selected and subjected to small controlled variations: solvent fraction, temperature, pH and buffer concentration. As our model comprised quadratic terms instead of a simple linear model, we chose a D-optimal design in order to minimize the experiment number. As a previous batch-to-batch study [K. Le Mapihan, Caractérisation et classification des phases stationnaires utilisées pour l'analyse CPL de produits pharmaceutiques, Ph.D. Thesis, Pierre and Marie Curie University, 2004] had shown a low variability on the selected stationary phase, it was then possible to split the design into two parts, according to the solvent nature, each using one column. Actually, our testing procedure involving assays both with methanol and with acetonitrile as organic modifier, such an approach enabled to avoid a possible bias due to the column ageing considering the number of experiments required (16 + 6 center points). Experimental results were computed thanks to a Partial Least Squares regression procedure, more adapted than the classical regression to handle factors and responses not completely independent. The results showed the behavior of the solutes in relation to their physico-chemical properties and the relevance of the second term degree of our model. Finally, the robust domain of the test has been fairly identified, so that any potential user precisely knows to which extend each experimental parameter must be controlled when our testing procedure is to be implemented.

Tropical Tropospheric Ozone Climatology: Approaches Based on SHADOZ Observations

NASA Technical Reports Server (NTRS)

Thompson, Anne M.; Witte, Jacquelyn C.; Chatfield, Robert B.; Hudson, Robert D.; Andrade, Marcos; Coetzee, Geert J. R.; Posny, Francoise

2004-01-01

The SHADOZ (Southern Hemisphere Additional Ozonesondes) ozone sounding network was initiated in 1998 to improve the coverage of tropical in-situ ozone measurements for satellite validation, algorithm development and related process studies. Over 2000 soundings have been archived at the central website, , for 12 stations that span the entire equatorial zone [Thompson et al., JGR, 108,8238, 2003]. The most striking features of tropospheric ozone profiles in SHADOZ are: (1) persistent longitudinal variability in tropospheric ozone profiles, with a 10-15 DU column-integrated difference between Atlantic and Pacific sites; (2) intense short-term variability triggered by changing meteorological conditions and advection of pollution. The implications of these results for profile climatologies and trends are described along with several approaches to classifying ozone profiles: 1) Seasonal means during MAM (March-April-May) and SON (September-October-November); 2) Maxima and minima, identified through correlation of TOMS-derived TTO (tropical tropospheric ozone) column depth with the sonde integrated tropospheric ozone column; and 3) Meteorological regimes, a technique that is effective in the subtropics where tropical and mid-latitude conditions alternate.

Hepatotoxic microcystin removal using pumice embedded monolithic composite cryogel as an alternative water treatment method.

PubMed

Gurbuz, Fatma; Ceylan, Şeyda; Odabaşı, Mehmet; Codd, Geoffrey A

2016-03-01

Microcystins are the most commonly encountered water-borne cyanotoxins which present short- and long-term risks to human health. Guidelines at international and national level, and legislation in some countries, have been introduced for the effective health risk management of these potent hepatotoxic, tumour-promoters. The stable cyclic structure of microcystins and their common production by cyanobacteria in waterbodies at times of high total dissolved organic carbon content presents challenges to drinking water treatment facilities, with conventional, advanced and novel strategies under evaluation. Here, we have studied the removal of microcystins using three different forms of pumice particles (PPs), which are embedded into macroporous cryogel columns. Macroporous composite cryogel columns (MCCs) are a new generation of separation media designed to face this challenging task. Three different MCCs were prepared by adding plain PPs, Cu(2+)-attached PPs and Fe(3+)-attached PPs to reaction media before the cryogelation step. Column studies showed that MCCs could be successfully used as an alternative water treatment method for successful microcystin removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Numerical Analysis of Infiltration Into a Sand Profile Bounded by a Capillary Fringe

NASA Astrophysics Data System (ADS)

Curtis, Alan A.; Watson, Keith K.

1980-04-01

The rapid response sometimes observed in a tile drain system following surface ponding of water is discussed in terms of the air compressibility effect. An earlier numerical study describing water movement into a bounded profile with a lower boundary impermeable to the passage of both air and water is reviewed with particular reference to the validity of the time-dependent boundary condition transformation used in simulating the inhibiting effects of the air pressure increase on infiltration. The extension of the transformation approach to a profile bounded by a capillary fringe is then considered in detail, and the results of numerical analyses are presented for infiltration into two columns of a fine sand initially in hydraulic equilibrium from a prior gravity drainage regime. The shorter column develops a steady state flow condition at short times which is consistent with earlier experimental findings. In contrast, the pressure of the entrapped air in the longer column gradually increases as infiltration proceeds until the analysis is terminated when air escape through the lower boundary is imminent.

Validation of TES ammonia observations at the single pixel scale in the San Joaquin Valley during DISCOVER-AQ

NASA Astrophysics Data System (ADS)

Sun, Kang; Cady-Pereira, Karen; Miller, David J.; Tao, Lei; Zondlo, Mark A.; Nowak, John B.; Neuman, J. A.; Mikoviny, Tomas; Müller, Markus; Wisthaler, Armin; Scarino, Amy J.; Hostetler, Chris A.

2015-05-01

Ammonia measurements from a vehicle-based, mobile open-path sensor and those from aircraft were compared with Tropospheric Emission Spectrometer (TES) NH3 columns at the pixel scale during the NASA Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality field experiment. Spatial and temporal mismatches were reduced by having the mobile laboratory sample in the same areas as the TES footprints. To examine how large heterogeneities in the NH3 surface mixing ratios may affect validation, a detailed spatial survey was performed within a single TES footprint around the overpass time. The TES total NH3 column above a single footprint showed excellent agreement with the in situ total column constructed from surface measurements with a difference of 2% (within the combined measurement uncertainties). The comparison was then extended to a TES transect of nine footprints where aircraft data (5-80 ppbv) were available in a narrow spatiotemporal window (<10 km, <1 h). The TES total NH3 columns above the nine footprints agreed to within 6% of the in situ total columns derived from the aircraft-based measurements. Finally, to examine how TES captures surface spatial gradients at the interpixel scale, ground-based, mobile measurements were performed directly underneath a TES transect, covering nine footprints within ±1.5 h of the overpass. The TES total columns were strongly correlated (R2 = 0.82) with the median NH3 mixing ratios measured at the surface. These results provide the first in situ validation of the TES total NH3 column product, and the methodology is applicable to other satellite observations of short-lived species at the pixel scale.

In vitro investigations of propulsion during laser lithotripsy using video tracking.

PubMed

Eisel, Maximilian; Ströbl, Stephan; Pongratz, Thomas; Strittmatter, Frank; Sroka, Ronald

2018-04-01

Ureteroscopic laser lithotripsy is an important and widely used method for destroying ureter stones. It represents an alternative to ultrasonic and pneumatic lithotripsy techniques. Although these techniques have been thoroughly investigated, the influence of some physical parameters that may be relevant to further improve the treatment results is not fully understood. One crucial topic is the propulsive stone movement induced by the applied laser pulses. To simplify and speed up the optimization of laser parameters in this regard, a video tracking method was developed in connection with a vertical column setup that allows recording and subsequently analyzing the propulsive stone movement in dependence of different laser parameters in a particularly convenient and fast manner. Pulsed laser light was applied from below to a cubic BegoStone phantom loosely guided within a vertical column setup. The video tracking method uses an algorithm to determine the vertical stone position in each frame of the recorded scene. The time-dependence of the vertical stone position is characterized by an irregular series of peaks. By analyzing the slopes of the peaks in this signal it was possible to determine the mean upward stone velocity for a whole pulse train and to compare it for different laser settings. For a proof of principle of the video tracking method, a specific pulse energy setting (1 J/pulse) was used in combination with three different pulse durations: short pulse (0.3 ms), medium pulse (0.6 ms), and long pulse (1.0 ms). The three pulse durations were compared in terms of their influence on the propulsive stone movement in terms of upward velocity. Furthermore, the propulsions induced by two different pulse energy settings (0.8 J/pulse and 1.2 J/pulse) for a fixed pulse duration (0.3 ms) were compared. A pulse repetition rate of 10 Hz was chosen for all experiments, and for each laser setting, the experiment was repeated on 15 different freshly prepared stones. The latter set of experiments was compared with the results of previous propulsion measurements performed with a pendulum setup. For a fixed pulse energy (1 J/pulse), the mean upward propulsion velocity increased (from 120.0 to 154.9 mm · s -1 ) with decreasing pulse duration. For fixed pulse duration (0.3 ms), the mean upward propulsion velocity increased (from 91.9 to 123.3 mm · s -1 ) with increasing pulse energy (0.8 J/pulse and 1.2 J/pulse). The latter result corresponds roughly to the one obtained with the pendulum setup (increase from 61 to 105 mm · s -1 ). While the mean propulsion velocities for the two different pulse energies were found to differ significantly (P < 0.001) for the two experimental and analysis methods, the standard deviations of the measured mean propulsion velocities were considerably smaller in case of the vertical column method with video tracking (12% and 15% for n = 15 freshly prepared stones) than in case of the pendulum method (26% and 41% for n = 50 freshly prepared stones), in spite of the considerably smaller number of experiment repetitions ("sample size") in the first case. The proposed vertical column method with video tracking appears advantageous compared to the pendulum method in terms of the statistical significance of the obtained results. This may partly be understood by the fact that the entire motion of the stones contributes to the data analysis, rather than just their maximum distance from the initial position. The key difference is, however, that the pendulum method involves only one single laser pulse in each experiment run, which renders this method rather tedious to perform. Furthermore, the video tracking method appears much better suited to model a clinical lithotripsy intervention that utilizes longer series of laser pulses at higher repetition rates. The proposed video tracking method can conveniently and quickly deliver results for a large number of laser pulses that can easily be averaged. An optimization of laser settings to achieve minimal propulsive stone movement should thus be more easily feasible with the video tracking method in connection with the vertical column setup. Lasers Surg. Med. 50:333-339, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Short term memory for single surface features and bindings in ageing: A replication study.

PubMed

Isella, Valeria; Molteni, Federica; Mapelli, Cristina; Ferrarese, Carlo

2015-06-01

In the present study we replicated a previous experiment investigating visuo-spatial short term memory binding in young and older healthy individuals, in the attempt to verify the pattern of impairment that can be observed in normal elderly for short term memory for single items vs short term memory for bindings. Assessing a larger sample size (25 young and 25 older subjects), using a more appropriate measure of accuracy for a change detection task (A'), and adding the evaluation of speed of performance, we confirmed that old normals show a decline in short term memory for bindings of shape and colour that is of comparable extent, and not major, to the decline in memory for single shapes and single colours. The absence of a specific deficit of short term memory for conjunctions of surface features seems to distinguish cognitive ageing from Alzheimer's Disease. Copyright © 2015 Elsevier Inc. All rights reserved.

An Exemplar-Familiarity Model Predicts Short-Term and Long-Term Probe Recognition across Diverse Forms of Memory Search

ERIC Educational Resources Information Center

Nosofsky, Robert M.; Cox, Gregory E.; Cao, Rui; Shiffrin, Richard M.

2014-01-01

Experiments were conducted to test a modern exemplar-familiarity model on its ability to account for both short-term and long-term probe recognition within the same memory-search paradigm. Also, making connections to the literature on attention and visual search, the model was used to interpret differences in probe-recognition performance across…

Semantic contribution to verbal short-term memory: are pleasant words easier to remember than neutral words in serial recall and serial recognition?

PubMed

Monnier, Catherine; Syssau, Arielle

2008-01-01

In the four experiments reported here, we examined the role of word pleasantness on immediate serial recall and immediate serial recognition. In Experiment 1, we compared verbal serial recall of pleasant and neutral words, using a limited set of items. In Experiment 2, we replicated Experiment 1 with an open set of words (i.e., new items were used on every trial). In Experiments 3 and 4, we assessed immediate serial recognition of pleasant and neutral words, using item sets from Experiments 1 and 2. Pleasantness was found to have a facilitation effect on both immediate serial recall and immediate serial recognition. This study supplies some new supporting arguments in favor of a semantic contribution to verbal short-term memory performance. The pleasantness effect observed in immediate serial recognition showed that, contrary to a number of earlier findings, performance on this task can also turn out to be dependent on semantic factors. The results are discussed in relation to nonlinguistic and psycholinguistic models of short-term memory.

Travel Abroad: A Study of the Perceived Influence of High School Students' Experiences of Short-Term Travel or Study Abroad Prior to College

ERIC Educational Resources Information Center

Angwenyi, David Matara

2014-01-01

Students who participate in a short-term travel experience program of 4 weeks or less develop a sense of global citizenship. High school students who spend time traveling abroad might seek to address global issues, not only from a local perspective, but also from a global perspective. The Troika Study guided this study. Using qualitative…

Full-length U-xPu-10Zr (x = 0, 8, 19 wt.%) fast reactor fuel test in FFTF

NASA Astrophysics Data System (ADS)

Porter, D. L.; Tsai, Hanchung

2012-08-01

The Integral Fast Reactor-1 (IFR-1) experiment performed in the Fast Flux Test Facility (FFTF) was the only U-Pu-10Zr (Pu-0, 8 and 19 wt.%) metallic fast reactor test with commercial-length (91.4-cm active fuel-column length) conducted to date. With few remaining test reactors, there is little opportunity for performing another test with a long active fuel column. The assembly was irradiated to the goal burnup of 10 at.%. The beginning-of-life (BOL) peak cladding temperature of the hottest pin was 608 °C, cooling to 522 °C at end-of-life (EOL). Selected fuel pins were examined non-destructively using neutron radiography, precision axial gamma scanning, and both laser and spiral contact cladding profilometry. Destructive exams included plenum gas pressure, volume, and gas composition determinations on a number of pins followed by optical metallography, electron probe microanalysis (EPMA), and alpha and beta-gamma autoradiography on a single U-19Pu-10Zr pin. The post-irradiation examinations (PIEs) showed very few differences compared to the short-pin (34.3-cm fuel column) testing performed on fuels of similar composition in Experimental Breeder Reactor-II (EBR-II). The fuel column grew axially slightly less than observed in the short pins, but with the same pattern of decreasing growth with increasing Pu content. There was a difference in the fuel-cladding chemical interaction (FCCI) in that the maximum cladding penetration by interdiffusion with fuel/fission products did not occur at the top of the fuel column where the cladding temperature is highest, as observed in EBR-II tests. Instead, the more exaggerated fission-rate profile of the FFTF pins resulted in a peak FCCI at ˜0.7 X/L axial location along the fuel column. This resulted from a higher production of rare-earth fission products at this location and a higher ΔT between fuel center and cladding than at core center, together providing more rare earths at the cladding and more FCCI. This behavior could actually help extend the life of a fuel pin in a "long pin" reactor design to a higher peak fuel burnup.

Free recall in Williams syndrome: is there a dissociation between short- and long-term memory?

PubMed

Brock, Jon; Brown, Gordon D A; Boucher, Jill

2006-04-01

Two experiments used the free recall paradigm to investigate verbal memory abilities in Williams syndrome (WS)--a rare genetic disorder. In an earlier free recall study, Vicari et al. (1996a) reported that, unlike TD controls, children with WS showed a recency effect but failed to show a primacy effect. These authors interpreted their findings as evidence for a dissociation between relatively strong verbal short-term memory and relatively impaired verbal long-term memory. In Experiment 1 of the current study, children with WS and TD controls showed comparable improvements in performance with repeated testing of the same material, indicating similar long-term learning of the test items. Neither group showed evidence of primacy effects. However, the extent of primacy effects in free recall is known to depend on the rehearsal strategy that participants adopt. In Experiment 2, therefore, participants were encouraged to engage in overt cumulative rehearsal. This manipulation resulted in significant and comparable primacy effects in both groups, although neither group demonstrated a significant change in overall performance. There was therefore no evidence from either experiment for a dissociation between short- and long-term verbal memory in WS.

Catalytic wet oxidation: mathematical modeling of multicompound destruction.

PubMed

Yang, J; Hand, D W; Hokanson, D R; Crittenden, J C; Oman, E J

2003-01-01

A mathematical model of a three-phase catalytic reactor, CatReac, was developed for analysis and optimization of a catalytic oxidation reactor that is used in the International Space Station potable water processor. The packed-bed catalytic reactor, known as the volatile reactor assembly (VRA), is operated as a three-phase reactor and contains a proprietary catalyst, a pure-oxygen gas phase, and the contaminated water. The contaminated water being fed to the VRA primarily consists of acetic acid, acetone, ethanol, 1-propanol, 2-propanol, and propionic acid ranging in concentration from 1 to 10 mg/L. The Langmuir-Hinshelwood Hougen-Watson (L-H) (Hougen, 1943) expression was used to describe the surface reaction rate for these compounds. Single and multicompound short-column experiments were used to determine the L-H rate parameters and calibrate the model. The model was able to predict steady-state multicomponent effluent profiles for short and full-scale reactor experiments.

Determination of rate constants and branching ratios for TCE degradation by zero-valent iron using a chain decay multispecies model.

PubMed

Hwang, Hyoun-Tae; Jeen, Sung-Wook; Sudicky, Edward A; Illman, Walter A

2015-01-01

The applicability of a newly-developed chain-decay multispecies model (CMM) was validated by obtaining kinetic rate constants and branching ratios along the reaction pathways of trichloroethene (TCE) reduction by zero-valent iron (ZVI) from column experiments. Changes in rate constants and branching ratios for individual reactions for degradation products over time for two columns under different geochemical conditions were examined to provide ranges of those parameters expected over the long-term. As compared to the column receiving deionized water, the column receiving dissolved CaCO3 showed higher mean degradation rates for TCE and all of its degradation products. However, the column experienced faster reactivity loss toward TCE degradation due to precipitation of secondary carbonate minerals, as indicated by a higher value for the ratio of maximum to minimum TCE degradation rate observed over time. From the calculated branching ratios, it was found that TCE and cis-dichloroethene (cis-DCE) were dominantly dechlorinated to chloroacetylene and acetylene, respectively, through reductive elimination for both columns. The CMM model, validated by the column test data in this study, provides a convenient tool to determine simultaneously the critical design parameters for permeable reactive barriers and natural attenuation such as rate constants and branching ratios. Copyright © 2015 Elsevier B.V. All rights reserved.

Method for determination of aflatoxin M₁ in cheese and butter by HPLC using an immunoaffinity column.

PubMed

Sakuma, Hisako; Kamata, Yoichi; Sugita-Konishi, Yoshiko; Kawakami, Hiroshi

2011-01-01

A rapid, sensitive convenient method for determination of aflatoxin M₁ (AFM₁) in cheese and butter by HPLC was developed and validated. The method employs a safe extraction solution (mixture of acetonitrile, methanol and water) and an immunoaffinity column (IAC) for clean-up. Compared with the widely used method employing chloroform and a Florisil column, the IAC method has a short analytical time and there are no interference peaks. The limits of quantification (LOQ) of the IAC method were 0.12 and 0.14 µg/kg, while those of the Florisil column method were 0.47 and 0.23 µg/kg in cheese and buffer, respectively. The recovery and relative standard deviation (RSD) for cheese (spiked at 0.5 µg/kg) in the IAC method were 92% and 7%, respectively, while for the Florisil column method the corresponding values were 76% and 10%. The recovery and RSD for butter (spiked at 0.5 µg/kg) in the IAC method were 97% and 9%, and those in the Florisil method were 74% and 9%, respectively. In the IAC method, the values of in-house precision (n=2, day=5) of cheese and butter (spiked at 0.5 µg/kg) were 9% and 13%, respectively. The IAC method is superior to the Florisil column method in terms of safety, ease of handling, sensitivity and reliability. A survey of AFM₁ contamination in imported cheese and butter in Japan was conducted by the IAC method. AFM₁ was not detected in 60 samples of cheese and 30 samples of butter.

Short-term and long-term attentional biases to frequently encountered target features.

PubMed

Sha, Li Z; Remington, Roger W; Jiang, Yuhong V

2017-07-01

It has long been known that frequently occurring targets are attended better than infrequent ones in visual search. But does this frequency-based attentional prioritization reflect momentary or durable changes in attention? Here we observed both short-term and long-term attentional biases for visual features as a function of different types of statistical associations between the targets, distractors, and features. Participants searched for a target, a line oriented horizontally or vertically among diagonal distractors, and reported its length. In one set of experiments we manipulated the target's color probability: Targets were more often in Color 1 than in Color 2. The distractors were in other colors. Participants found Color 1 targets more quickly than Color 2 targets, but this preference disappeared immediately when the target's color became random in the subsequent testing phase. In the other set of experiments, we manipulated the diagnostic values of the two colors: Color 1 was more often a target than a distractor; Color 2 was more often a distractor than a target. Participants found Color 1 targets more quickly than Color 2 targets. Importantly, and in contrast to the first set of experiments, the featural preference was sustained in the testing phase. These results suggest that short-term and long-term attentional biases are products of different statistical information. Finding a target momentarily activates its features, inducing short-term repetition priming. Long-term changes in attention, on the other hand, may rely on learning diagnostic features of the targets.

Impact of Spatial and Verbal Short-Term Memory Load on Auditory Spatial Attention Gradients.

PubMed

Golob, Edward J; Winston, Jenna; Mock, Jeffrey R

2017-01-01

Short-term memory load can impair attentional control, but prior work shows that the extent of the effect ranges from being very general to very specific. One factor for the mixed results may be reliance on point estimates of memory load effects on attention. Here we used auditory attention gradients as an analog measure to map-out the impact of short-term memory load over space. Verbal or spatial information was maintained during an auditory spatial attention task and compared to no-load. Stimuli were presented from five virtual locations in the frontal azimuth plane, and subjects focused on the midline. Reaction times progressively increased for lateral stimuli, indicating an attention gradient. Spatial load further slowed responses at lateral locations, particularly in the left hemispace, but had little effect at midline. Verbal memory load had no (Experiment 1), or a minimal (Experiment 2) influence on reaction times. Spatial and verbal load increased switch costs between memory encoding and attention tasks relative to the no load condition. The findings show that short-term memory influences the distribution of auditory attention over space; and that the specific pattern depends on the type of information in short-term memory.

Impact of Spatial and Verbal Short-Term Memory Load on Auditory Spatial Attention Gradients

PubMed Central

Golob, Edward J.; Winston, Jenna; Mock, Jeffrey R.

2017-01-01

Short-term memory load can impair attentional control, but prior work shows that the extent of the effect ranges from being very general to very specific. One factor for the mixed results may be reliance on point estimates of memory load effects on attention. Here we used auditory attention gradients as an analog measure to map-out the impact of short-term memory load over space. Verbal or spatial information was maintained during an auditory spatial attention task and compared to no-load. Stimuli were presented from five virtual locations in the frontal azimuth plane, and subjects focused on the midline. Reaction times progressively increased for lateral stimuli, indicating an attention gradient. Spatial load further slowed responses at lateral locations, particularly in the left hemispace, but had little effect at midline. Verbal memory load had no (Experiment 1), or a minimal (Experiment 2) influence on reaction times. Spatial and verbal load increased switch costs between memory encoding and attention tasks relative to the no load condition. The findings show that short-term memory influences the distribution of auditory attention over space; and that the specific pattern depends on the type of information in short-term memory. PMID:29218024

Redintegration, task difficulty, and immediate serial recall tasks.

PubMed

Ritchie, Gabrielle; Tolan, Georgina Anne; Tehan, Gerald

2015-03-01

While current theoretical models remain somewhat inconclusive in their explanation of short-term memory (STM), many theories suggest at least a contribution of long-term memory (LTM) to the short-term system. A number of researchers refer to this process as redintegration (e.g., Schweickert, 1993). Under short-term recall conditions, the current study investigated the effects of redintegration and task difficulty in order to extend research conducted by Neale and Tehan (2007). Thirty participants in Experiment 1 and 26 participants in Experiment 2 completed a serial recall task in which retention interval, presentation rate, and articulatory suppression were used to modify task difficulty. Redintegration was examined by manipulating the characteristics of the to-be-remembered items; lexicality in Experiment 1 and wordlikeness in Experiment 2. Responses were scored based on correct-in-position recall, item scoring, and order accuracy scoring. In line with the Neale and Tehan results, as the difficulty of the task increased so did the effects of redintegration. This was evident in that the advantage for words in Experiment 1 and wordlikeness in Experiment 2 decreased as task difficulty increased. This relationship was observed for item but not order memory, and findings were discussed in relation to the theory of redintegration. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Psychodynamic group psychotherapy: impact of group length and therapist professional characteristics on development of therapeutic alliance.

PubMed

Lorentzen, Steinar; Bakali, Jan Vegard; Hersoug, Anne Grete; Hagtvet, Knut A; Ruud, Torleif; Høglend, Per

2012-09-01

Little research has been done on therapeutic alliance in group psychotherapy, especially the impact of treatment duration and therapist professional characteristics. Therapeutic alliance was rated by patients on the Working Alliance Inventory-Short Form at three time points (sessions 3, 10 and 17) in a randomized controlled trial of short-term and long-term psychodynamic group psychotherapy. As predictors we selected therapist clinical experience and length of didactic training, which have demonstrated ambiguous results in previous research. Linear latent variable growth curve models (structural equation modeling) were developed for the three Working Alliance Inventory-Short Form subscales bond, task and goal. We found a significant variance in individual growth curves (intercepts and slopes) but no differential development due to group length. Longer therapist formal training had a negative impact on early values of subscale task in both treatments. There was an interaction between length of the therapists' clinical experience and group length on early bond, task and goal: therapists with longer clinical experience were rated lower on initial bond in the long-term group but less so in the short-term group. Longer clinical experience influenced initial task and goal positively in the short-term group but was unimportant for task or significantly negative for goal in the long-term group. There was no mean development of alliance, and group length did not differentially impact the alliance during 6 months. Early ratings of the three Working Alliance Inventory-Short Form subscales partly reflected different preparations of patients in the two group formats, partly therapist characteristics, but more research is needed to see how these aspects impact alliance development and outcome. Therapists should pay attention to all three aspects of the alliance, when they prepare patients for group therapy. In psychodynamic groups, length of therapy does not differentiate the overall level or the development of member-leader alliance. Within psychodynamic groups, each individual appear to have their unique perception of the member-leader alliance. Therapists with longer formal psychotherapy training may be less successful in establishing early agreement with patients on the tasks of psychodynamic group psychotherapy. Patients perceive a somewhat lower degree of early emotional bonding with the more clinically experienced therapists in long-term psychodynamics groups. Therapists with more clinical experience may contribute to a stronger degree of initial agreement with patients on the tasks and goals of short-term group psychotherapy. Copyright © 2011 John Wiley & Sons, Ltd.

Cross-cultural comparison of long-term care in the United States and Finland: Research done through a short-term study-abroad experience.

PubMed

Kruger, Tina M; Gilland, Sarah; Frank, Jacquelyn B; Murphy, Bridget C; English, Courtney; Meade, Jana; Morrow, Kaylee; Rush, Evan

2017-01-01

In May 2014, a short-term study-abroad experience was conducted in Finland through a course offered at Indiana State University (ISU). Students and faculty from ISU and Eastern Illinois University participated in the experience, which was created to facilitate a cross-cultural comparison of long-term-care settings in the United States and Finland. With its outstanding system of caring for the health and social needs of its aging populace, Finland is a logical model to examine when considering ways to improve the quality of life for older adults who require care in the United States . Those participating in the course visited a series of long-term-care facilities in the region surrounding Terre Haute, Indiana, then travelled to Lappeenranta, Finland to visit parallel sites. Through limited-participation observation and semistructured interviews, similarities and differences in experiences, educations, and policies affecting long-term care workers in the United States and Finland were identified and are described here.

Visual mental image generation does not overlap with visual short-term memory: a dual-task interference study.

PubMed

Borst, Gregoire; Niven, Elaine; Logie, Robert H

2012-04-01

Visual mental imagery and working memory are often assumed to play similar roles in high-order functions, but little is known of their functional relationship. In this study, we investigated whether similar cognitive processes are involved in the generation of visual mental images, in short-term retention of those mental images, and in short-term retention of visual information. Participants encoded and recalled visually or aurally presented sequences of letters under two interference conditions: spatial tapping or irrelevant visual input (IVI). In Experiment 1, spatial tapping selectively interfered with the retention of sequences of letters when participants generated visual mental images from aural presentation of the letter names and when the letters were presented visually. In Experiment 2, encoding of the sequences was disrupted by both interference tasks. However, in Experiment 3, IVI interfered with the generation of the mental images, but not with their retention, whereas spatial tapping was more disruptive during retention than during encoding. Results suggest that the temporary retention of visual mental images and of visual information may be supported by the same visual short-term memory store but that this store is not involved in image generation.

The loss of short-term visual representations over time: decay or temporal distinctiveness?

PubMed

Mercer, Tom

2014-12-01

There has been much recent interest in the loss of visual short-term memories over the passage of time. According to decay theory, visual representations are gradually forgotten as time passes, reflecting a slow and steady distortion of the memory trace. However, this is controversial and decay effects can be explained in other ways. The present experiment aimed to reexamine the maintenance and loss of visual information over the short term. Decay and temporal distinctiveness models were tested using a delayed discrimination task, in which participants compared complex and novel objects over unfilled retention intervals of variable length. Experiment 1 found no significant change in the accuracy of visual memory from 2 to 6 s, but the gap separating trials reliably influenced task performance. Experiment 2 found evidence for information loss at a 10-s retention interval, but temporally separating trials restored the fidelity of visual memory, possibly because temporally isolated representations are distinct from older memory traces. In conclusion, visual representations lose accuracy at some point after 6 s, but only within temporally crowded contexts. These findings highlight the importance of temporal distinctiveness within visual short-term memory. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Assurance of Learning in Short-Term, Study Abroad Programs

ERIC Educational Resources Information Center

Tucker, Mary L.; Gullekson, Nicole L.; McCambridge, Jim

2011-01-01

Business students are increasingly seeking international experience in short-term, study abroad programs to enhance their intercultural knowledge, intercultural communication skills, and global perspectives to be more competitive in the global arena. Intuitively, universities initiating these programs and the students sojourning abroad believe in…

Kinetic dissolution of carbonates and Mn oxides in acidic water: Measurement of in situ field rates and reactive transport modeling

USGS Publications Warehouse

Brown, J.G.; Glynn, P.D.

2003-01-01

The kinetics of carbonate and Mn oxide dissolution under acidic conditions were examined through the in situ exposure of pure phase samples to acidic ground water in Pinal Creek Basin, Arizona. The average long-term calculated in situ dissolution rates for calcite and dolomite were 1.65??10-7 and 3.64??10-10 mmol/(cm2 s), respectively, which were about 3 orders of magnitude slower than rates derived in laboratory experiments by other investigators. Application of both in situ and lab-derived calcite and dolomite dissolution rates to equilibrium reactive transport simulations of a column experiment did not improve the fit to measured outflow chemistry: at the spatial and temporal scales of the column experiment, the use of an equilibrium model adequately simulated carbonate dissolution in the column. Pyrolusite (MnO2) exposed to acidic ground water for 595 days increased slightly in weight despite thermodynamic conditions that favored dissolution. This result might be related to a recent finding by another investigator that the reductive dissolution of pyrolusite is accompanied by the precipitation of a mixed Mn-Fe oxide species. In PHREEQC reactive transport simulations, the incorporation of Mn kinetics improved the fit between observed and simulated behavior at the column and field scales, although the column-fitted rate for Mn-oxide dissolution was about 4 orders of magnitude greater than the field-fitted rate. Remaining differences between observed and simulated contaminant transport trends at the Pinal Creek site were likely related to factors other than the Mn oxide dissolution rate, such as the concentration of Fe oxide surface sites available for adsorption, the effects of competition among dissolved species for available surface sites, or reactions not included in the model.

Transport of Escherichia coli in 25 m quartz sand columns

NASA Astrophysics Data System (ADS)

Lutterodt, G.; Foppen, J. W. A.; Maksoud, A.; Uhlenbrook, S.

2011-01-01

To help improve the prediction of bacteria travel distances in aquifers laboratory experiments were conducted to measure the distant dependent sticking efficiencies of two low attaching Escherichia coli strains (UCFL-94 and UCFL-131). The experimental set up consisted of a 25 m long helical column with a diameter of 3.2 cm packed with 99.1% pure-quartz sand saturated with a solution of magnesium sulfate and calcium chloride. Bacteria mass breakthrough at sampling distances ranging from 6 to 25.65 m were observed to quantify bacteria attachment over total transport distances ( αL) and sticking efficiencies at large intra-column segments ( αi) (> 5 m). Fractions of cells retained ( Fi) in a column segment as a function of αi were fitted with a power-law distribution from which the minimum sticking efficiency defined as the sticking efficiency of 0.001% bacteria fraction of the total input mass retained that results in a 5 log removal were extrapolated. Low values of αL in the order 10 - 4 and 10 - 3 were obtained for UCFL-94 and UCFL-131 respectively, while αi-values ranged between 10 - 6 to 10 - 3 for UCFL-94 and 10 - 5 to 10 - 4 for UCFL-131. In addition, both αL and αi reduced with increasing transport distance, and high coefficients of determination (0.99) were obtained for power-law distributions of αi for the two strains. Minimum sticking efficiencies extrapolated were 10 - 7 and 10 - 8 for UCFL-94 and UCFL-131, respectively. Fractions of cells exiting the column were 0.19 and 0.87 for UCFL-94 and UCL-131, respectively. We concluded that environmentally realistic sticking efficiency values in the order of 10 - 4 and 10 - 3 and much lower sticking efficiencies in the order 10 - 5 are measurable in the laboratory, Also power-law distributions in sticking efficiencies commonly observed for limited intra-column distances (< 2 m) are applicable at large transport distances(> 6 m) in columns packed with quartz grains. High fractions of bacteria populations may possess the so-called minimum sticking efficiency, thus expressing their ability to be transported over distances longer than what might be predicted using measured sticking efficiencies from experiments with both short (< 1 m) and long columns (> 25 m). Also variable values of sticking efficiencies within and among the strains show heterogeneities possibly due to variations in cell surface characteristics of the strains. The low sticking efficiency values measured express the importance of the long columns used in the experiments and the lower values of extrapolated minimum sticking efficiencies makes the method a valuable tool in delineating protection areas in real-world scenarios.

Use of Polyphosphate to Decrease Uranium Leaching in Hanford 300 Area Smear Zone Sediments

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

Szecsody, James E.; Zhong, Lirong; Oostrom, Martinus

2012-09-30

The primary objective of this study is to summarize the laboratory investigations performed to evaluate short- and long-term effects of phosphate treatment on uranium leaching from 300 area smear zone sediments. Column studies were used to compare uranium leaching in phosphate-treated to untreated sediments over a year with multiple stop flow events to evaluate longevity of the uranium leaching rate and mass. A secondary objective was to compare polyphosphate injection, polyphosphate/xanthan injection, and polyphosphate infiltration technologies that deliver phosphate to sediment.

Effect of vertical active vibration isolation on tracking performance and on ride qualities

NASA Technical Reports Server (NTRS)

Dimasi, F. P.; Allen, R. E.; Calcaterra, P. C.

1972-01-01

An investigation to determine the effect on pilot performance and comfort of an active vibration isolation system for a commercial transport pilot seat is reported. The test setup consisted of: a hydraulic shaker which produced random vertical vibration inputs; the active vibration isolation system; the pilot seat; the pilot control wheel and column; the side-arm controller; and a two-axis compensatory tracking task. The effects of various degrees of pilot isolation on short-term (two-minute) tracking performance and comfort were determined.

Teaching through Trade Books: Growing a Garden

ERIC Educational Resources Information Center

Royce, Christine Anne

2008-01-01

Many people look forward to planting their own garden and enjoying its fruitage throughout the summer months. Gardening can be an excellent learning experience in many ways because it offers opportunities to learn about plants and to observe changes over time. This column focuses on a long-term project of understanding plant growth and planting…

Short-term memory and dual task performance

NASA Technical Reports Server (NTRS)

Regan, J. E.

1982-01-01

Two hypotheses concerning the way in which short-term memory interacts with another task in a dual task situation are considered. It is noted that when two tasks are combined, the activity of controlling and organizing performance on both tasks simultaneously may compete with either task for a resource; this resource may be space in a central mechanism or general processing capacity or it may be some task-specific resource. If a special relationship exists between short-term memory and control, especially if there is an identity relationship between short-term and a central controlling mechanism, then short-term memory performance should show a decrement in a dual task situation. Even if short-term memory does not have any particular identity with a controlling mechanism, but both tasks draw on some common resource or resources, then a tradeoff between the two tasks in allocating resources is possible and could be reflected in performance. The persistent concurrence cost in memory performance in these experiments suggests that short-term memory may have a unique status in the information processing system.

Experimental behaviour of beam-column connection using cold-formed steel sections with rectangular gusset-plate

NASA Astrophysics Data System (ADS)

Aminuddin, K. M.; Saggaff, Anis; Tahir, Mahmood Md

2017-11-01

Beam-to-column connections setting up as isolated joint of cold-formed steel sections were tested up to failure. This experiment was conducted to observe the behaviour of connection in term of strength, stiffness and ductility. The type of connection used was rectangular gusset plate which stiffen the beam-to-column connection. The behaviour of the proposed connection was expressed with Moment-Rotation curves plotted from the experiment test results. The capacity of connections on this research were done in two ways: theoretical calculation by adopting Eurocode 3 BS EN 1993-1-8:2005 and experimental test results. The theoretical calculation of the moment capacit y of the proposed connection has found (Mj) to be 10.78 kNm with joint stiffness (Sj) amount to 458.53 kNm/rad. The experimental test results has recorded that the Moment capacity (Mj) of 15.68 kNm with joint stiffness (Sj) of 1948.06 kNm/rad. The moment ratio of theoretical to experimental amount to 0.69. The joint stiffness ratio of theoretical to experimental amount to 0.24.

Repeatability of the efficiency of columns packed with sub-3μm core-shell particles: Part I. 2.6μm Kinetex-C(18) particles in 4.6mm and 2.1mm×100mm column formats.

PubMed

Gritti, Fabrice; Guiochon, Georges

2012-08-24

The column-to-column repeatability of the mass transfer mechanism in columns packed with sub-3μm shell particles was investigated. The parameters of this mechanism were measured for twelve columns (six 2.1mm×100mm and six 4.6mm×100mm) packed with the same batch of 2.6μm Kinetex-C(18) particles (Phenomenex, CA, USA). For both series, the manufacturer provided columns at different positions in the efficiency distribution given by the quality test control. Three compounds were used, uracil, naphthalene and insulin. The reduced longitudinal diffusion term was measured with the peak parking (PP) method, the reduced solid-liquid mass transfer resistance term was given by a combination of the PP results and a model of effective diffusion in ternary composite materials (non-porous cores, concentric porous shell, and eluent matrix), validated previously. The overall eddy diffusion term was obtained by subtraction of these two HETP terms from the overall reduced HETP measured by numerical integration of the entire peak profiles. The results demonstrate that the dispersion of the column efficiencies is only due to the random nature of the packing process. At the highest reduced velocity achieved, the relative standard deviations (RSDs) of the eddy diffusion term for the 2.1mm I.D. columns were ca. 7% and 3% for the low molecular weight compounds and for insulin, respectively. For the 4.6mm I.D. columns, these RSDs were 15% and 5%, respectively. The larger RSDs for the 4.6mm I.D. columns is explained by the exceptionally low value of the eddy diffusion term. Copyright © 2012 Elsevier B.V. All rights reserved.

An experiment for determining the Euler load by direct computation

NASA Technical Reports Server (NTRS)

Thurston, Gaylen A.; Stein, Peter A.

1986-01-01

A direct algorithm is presented for computing the Euler load of a column from experimental data. The method is based on exact inextensional theory for imperfect columns, which predicts two distinct deflected shapes at loads near the Euler load. The bending stiffness of the column appears in the expression for the Euler load along with the column length, therefore the experimental data allows a direct computation of bending stiffness. Experiments on graphite-epoxy columns of rectangular cross-section are reported in the paper. The bending stiffness of each composite column computed from experiment is compared with predictions from laminated plate theory.

Investigation the Effect of the Dispersant Corexit 9500A on the Movement of an Oil-In-Water Emulsion Through an Alabama Beach Sand

NASA Astrophysics Data System (ADS)

Steffy, D. A.; Nichols, A.

2016-02-01

A majority of Alabama's 60 miles of beaches were exposed to the crude oil released from the massive 2010 Deepwater Horizon Oil Spill. To help remediate the spill BP sprayed the dispersant, COREXIT 9500A, over the floating oil in the Gulf and at the subsurface damaged Macondo wellhead. This dispersant could have inadvertently promoted an oil-in-water emulsion to infiltrate deeper into the exposed beaches which are composed of Holocene age, fine-to-medium quartz sand. A series of short-column tests of packed sand in glass columns simulated the arrival of an oil-in-water emulsion at a beach. An emulsion formed by weathered oil penetrated deeper into the sand as compared to oil that has experience little weathering. The penetrations of these emulsions were enhanced when a 2% COREXIT 9500A in saltwater solution was allowed to flush through the sand column. Unfortunately, by adding a dispersant it probably promoted some oil-in-water components to be distributed deeper into coastal sand of Alabama.

Flow morphologies after oblique shock acceelration of a cylindrical density interface

NASA Astrophysics Data System (ADS)

Wayne, Patrick; Simons, Dylan; Olmstead, Dell; Truman, C. Randall; Vorobieff, Peter; Kumar, Sanjay

2015-11-01

We present an experimental study of instabilities developing after an oblique shock interaction with a heavy gas column. The heavy gas in our experiments is sulfur hexafluoride infused with 11% acetone by mass. A misalignment of the pressure and density gradients results in three-dimensional vorticity deposition on the gaseous interface, dtriggering the onset of Richtmyer-Meshkov instability (RMI). Shortly thereafter, other instabilities develop along the interface, including a shear-driven instability that presents itself on the leading (with respect to the shock) and trailing edges of the column. This leads to the development of rows of co-rotating ``cat's eye'' vortices, characteristic of Kelvin-Helmholtz instability (KHI). Characteristics of the KHI, such as growth rate and wavelength, depend on several factors including the Mach number of the shock, the shock tube angle of inclination α (equal to the angle between the axis of the column and the plane of the shock), and the Atwood number. This work is supported by the US National Nuclear Security Agency (NNSA) via grant DE-NA0002913.

Misremembering what you see or hear: Dissociable effects of modality on short- and long-term false recognition.

PubMed

Olszewska, Justyna M; Reuter-Lorenz, Patricia A; Munier, Emily; Bendler, Sara A

2015-09-01

False working memories readily emerge using a visual item-recognition variant of the converging associates task. Two experiments, manipulating study and test modality, extended prior working memory results by demonstrating a reliable false recognition effect (more false alarms to associatively related lures than to unrelated lures) within seconds of encoding in either the visual or auditory modality. However, false memories were nearly twice as frequent when study lists were seen than when they were heard, regardless of test modality, although study-test modality mismatch was generally disadvantageous (consistent with encoding specificity). A final experiment that varied study-test modality using a hybrid short- and long-term memory test (Flegal, Atkins & Reuter-Lorenz, 2010) replicated the auditory advantage in the short term but revealed a reversal in the long term: The false memory effect was greater in the auditory study-test condition than in the visual study-test condition. Thus, the same encoding conditions gave rise to an opposite modality advantage depending on whether recognition was tested under short-term or long-term memory conditions. Although demonstrating continuity in associative processing across delay, the results indicate that delay condition affects the availability of modality-dependent features of the memory trace and, thus, distinctiveness, leading to dissociable patterns of short- and long-term memory performance. (c) 2015 APA, all rights reserved).

Collapse of tall granular columns in fluid

NASA Astrophysics Data System (ADS)

Kumar, Krishna; Soga, Kenichi; Delenne, Jean-Yves

2017-06-01

Avalanches, landslides, and debris flows are geophysical hazards, which involve rapid mass movement of granular solids, water, and air as a multi-phase system. In order to describe the mechanism of immersed granular flows, it is important to consider both the dynamics of the solid phase and the role of the ambient fluid. In the present study, the collapse of a granular column in fluid is studied using 2D LBM - DEM. The flow kinematics are compared with the dry and buoyant granular collapse to understand the influence of hydrodynamic forces and lubrication on the run-out. In the case of tall columns, the amount of material destabilised above the failure plane is larger than that of short columns. Therefore, the surface area of the mobilised mass that interacts with the surrounding fluid in tall columns is significantly higher than the short columns. This increase in the area of soil - fluid interaction results in an increase in the formation of turbulent vortices thereby altering the deposit morphology. It is observed that the vortices result in the formation of heaps that significantly affects the distribution of mass in the flow. In order to understand the behaviour of tall columns, the run-out behaviour of a dense granular column with an initial aspect ratio of 6 is studied. The collapse behaviour is analysed for different slope angles: 0°, 2.5°, 5° and 7.5°.

Intelsat two-way time transfer experiments between Japan, Korea and Taiwan

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

Engelkemier, B.; Imamura, K.; Takahashi, F.

This paper describes the first two-way time transfer experiments using Intelsat Ku-band satellites in eastern Asia performed by Communications Research Laboratory (CRL: Japan), Korea Research Institute of Standard and Science (KRISS: Korea) and Telecommunication Laboratory (TL: Taiwan) in 1992. The experiments are based on the recommendation of Conference Generale des Poids et Mesures (CGPM) in 1987. Also they are based on the international cooperation program between CRL and KRISS, and institute-level cooperation between CRL and TL. The experiments attained the short-term precision better than 1 ns, which is much better than conventional GPS time transfer. Long-term precision was not somore » good as short-term one. We discuss the reasons of the long-term instabilities. We can also established the procedures to use Intelsat satellites under the support of Intelsat Headquarters and each countries` common carrier agents.« less

Effects of initial iron corrosion rate on long-term performance of iron permeable reactive barriers: column experiments and numerical simulation.

PubMed

suk O, Jin; Jeen, Sung-Wook; Gillham, Robert W; Gui, Lai

2009-01-26

Column experiments and numerical simulation were conducted to test the hypothesis that iron material having a high corrosion rate is not beneficial for the long-term performance of iron permeable reactive barriers (PRBs) because of faster passivation of iron and greater porosity loss close to the influent face of the PRBs. Four iron materials (Connelly, Gotthart-Maier, Peerless, and ISPAT) were used for the column experiments, and the changes in reactivity toward cis-dichloroethene (cis-DCE) degradation in the presence of dissolved CaCO3 were evaluated. The experimental results showed that the difference in distribution of the accumulated precipitates, resulting from differences in iron corrosion rate, caused a difference in the migration rate of the cis-DCE profiles and a significant difference in the pattern of passivation, indicating a faster passivation in the region close to the influent end for the material having a higher corrosion rate. For the numerical simulation, the accumulation of secondary minerals and reactivity loss of iron were coupled using an empirically-derived relationship that was incorporated into a multi-component reactive transport model. The simulation results provided a reasonable representation of the evolution of iron reactivity toward cis-DCE treatment and the changes in geochemical conditions for each material, consistent with the observed data. The simulations for long-term performance were also conducted to further test the hypothesis and predict the differences in performance over a period of 40 years under typical groundwater conditions. The predictions showed that the cases of higher iron corrosion rates had earlier cis-DCE breakthrough and more reduction in porosity starting from near the influent face, due to more accumulation of carbonate minerals in that region. Therefore, both the experimental and simulation results appear to support the hypothesis and suggest that reactivity changes of iron materials resulting from evolution of geochemical conditions should be considered in the design of iron PRBs.

Acid rock drainage passive remediation using alkaline clay and impacts of vegetation and saturated sand barrier

NASA Astrophysics Data System (ADS)

Plaza, F.; Wen, Y.; Liang, X.

2017-12-01

Acid rock drainage (ARD) caused by abundance of coal refuse (CR) deposits in mining regions requires adequate treatment to prevent serious water pollution due to its acidity and high concentrations of sulfate and metals/metalloids. Over the past decades, various approaches have been explored and developed to remediate ARD. This study uses laboratory experiments to investigate the effectiveness and impacts of ARD passive remediation using alkaline clay (AC), a by-product of the aluminum refining process. Twelve column kinetic leaching experiments were set up with CR/AC mixing ratios ranging from 1%AC to 10%AC. Samples were collected from these columns to measure the pH, sulfate, metals/metalloids, acidity and alkalinity. Additional tests of XRD and acid base accounting were also conducted to better characterize the mineral phase in terms of the alkalinity and acidity potential. Based on the leachate measurement results, these columns were further classified into two groups of neutral/near neutral pH and acidic pH for further analysis. In addition, impacts of the vegetation and saturated sand layer on the remediation effectiveness were explored. The results of our long-term (more than three years in some cases) laboratory experiments show that AC is an effective ARD remediation material for the neutralization of leachate pH and immobilization of sulfate and metals such as Fe, Mn, Cu, Zn, Ni, Pb, Cd, Co. The CR/AC mixing ratios higher than 3%AC are found to be effective, with 10% close to optimal. Moreover, the results demonstrate the benefits of using vegetation and a saturated sand barrier. Vegetation acted as a phytoaccumulation/phytoextraction agent, causing an additional immobilization of metals. The saturated sand barrier blocked the oxygen and water diffusion downwards, leading to a reduction of the pyrite oxidation rate. Finally, the proposed remediation approach shows that the acidity consumption will likely occur before all the alkalinity is exhausted, guaranteeing an adequate long-term performance of this remediation approach.

Assessing the Effectiveness of First Step to Success: Are Short-Term Results the First Step to Long-Term Behavioral Improvements?

ERIC Educational Resources Information Center

Sumi, W. Carl; Woodbridge, Michelle W.; Javitz, Harold S.; Thornton, S. Patrick; Wagner, Mary; Rouspil, Kristen; Yu, Jennifer W.; Seeley, John R.; Walker, Hill M.; Golly, Annemieke; Small, Jason W.; Feil, Edward G.; Severson, Herbert H.

2013-01-01

This article reports on the effectiveness of First Step to Success, a secondary-level intervention appropriate for students in early elementary school who experience moderate to severe behavior problems and are at risk for academic failure. The authors demonstrate the intervention's short-term effects on multiple behavioral and academic outcomes…

Slave to the Rhythm: Experimental Tests of a Model for Verbal Short-Term Memory and Long-Term Sequence Learning

ERIC Educational Resources Information Center

Hitch, Graham J.; Flude, Brenda; Burgess, Neil

2009-01-01

Three experiments tested predictions of a neural network model of phonological short-term memory that assumes separate representations for order and item information, order being coded via a context-timing signal [Burgess, N., & Hitch, G. J. (1999). Memory for serial order: A network model of the phonological loop and its timing. "Psychological…

The Effect of Short-Term Study Abroad Experience on American Students' Leadership Skills and Career Aspirations

ERIC Educational Resources Information Center

Geyer, Alexis; Putz, Jenni; Misra, Kaustav

2017-01-01

Purpose: Building on existing study abroad literature, the purpose of this paper is to assess the impact of both short-term and long-term study abroad programs on students' leadership skills and their career aspirations. Design/methodology/approach: A sample of college students were invited to complete an electronic survey about their experiences…

Improved quality-by-design compliant methodology for method development in reversed-phase liquid chromatography.

PubMed

Debrus, Benjamin; Guillarme, Davy; Rudaz, Serge

2013-10-01

A complete strategy dedicated to quality-by-design (QbD) compliant method development using design of experiments (DOE), multiple linear regressions responses modelling and Monte Carlo simulations for error propagation was evaluated for liquid chromatography (LC). The proposed approach includes four main steps: (i) the initial screening of column chemistry, mobile phase pH and organic modifier, (ii) the selectivity optimization through changes in gradient time and mobile phase temperature, (iii) the adaptation of column geometry to reach sufficient resolution, and (iv) the robust resolution optimization and identification of the method design space. This procedure was employed to obtain a complex chromatographic separation of 15 antipsychotic basic drugs, widely prescribed. To fully automate and expedite the QbD method development procedure, short columns packed with sub-2 μm particles were employed, together with a UHPLC system possessing columns and solvents selection valves. Through this example, the possibilities of the proposed QbD method development workflow were exposed and the different steps of the automated strategy were critically discussed. A baseline separation of the mixture of antipsychotic drugs was achieved with an analysis time of less than 15 min and the robustness of the method was demonstrated simultaneously with the method development phase. Copyright © 2013 Elsevier B.V. All rights reserved.

Independence of long-term contextual memory and short-term perceptual hypotheses: Evidence from contextual cueing of interrupted search.

PubMed

Schlagbauer, Bernhard; Mink, Maurice; Müller, Hermann J; Geyer, Thomas

2017-02-01

Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several trials, that is, the memory supporting "contextual cueing." In three experiments, we investigated the relationship between short-term perceptual hypotheses and long-term contextual memory. The results indicated that long-term, contextual memory of repeated displays neither affected the generation nor the confirmation of short-term perceptual hypotheses for these displays. Furthermore, the analysis of eye movements suggests that long-term memory provides an initial benefit in guiding attention to the target, whereas in subsequent looks guidance is entirely based on short-term perceptual hypotheses. Overall, the results reveal a picture of both long- and short-term memory contributing to reliable performance gains in interrupted search, while exerting their effects in an independent manner.

Exposure to violent media: the effects of songs with violent lyrics on aggressive thoughts and feelings.

PubMed

Anderson, Craig A; Carnagey, Nicholas L; Eubanks, Janie

2003-05-01

Five experiments examined effects of songs with violent lyrics on aggressive thoughts and hostile feelings. Experiments 1, 3, 4 and 5 demonstrated that college students who heard a violent song felt more hostile than those who heard a similar but nonviolent song. Experiments 2-5 demonstrated a similar increase in aggressive thoughts. These effects replicated across songs and song types (e.g., rock, humorous, nonhumorous). Experiments 3-5 also demonstrated that trait hostility was positively related to state hostility but did not moderate the song lyric effects. Discussion centers on the potential role of lyric content on aggression in short-term settings, relation to catharsis and other media violence domains, development of aggressive personality, differences between long-term and short-term effects, and possible mitigating factors.

Use of column experiments to investigate the fate of organic micropollutants - a review

NASA Astrophysics Data System (ADS)

Banzhaf, Stefan; Hebig, Klaus H.

2016-09-01

Although column experiments are frequently used to investigate the transport of organic micropollutants, little guidance is available on what they can be used for, how they should be set up, and how the experiments should be carried out. This review covers the use of column experiments to investigate the fate of organic micropollutants. Alternative setups are discussed together with their respective advantages and limitations. An overview is presented of published column experiments investigating the transport of organic micropollutants, and suggestions are offered on how to improve the comparability of future results from different experiments. The main purpose of column experiments is to investigate the transport and attenuation of a specific compound within a specific sediment or substrate. The transport of (organic) solutes in groundwater is influenced by the chemical and physical properties of the compounds, the solvent (i.e., the groundwater, including all solutes), and the substrate (the aquifer material). By adjusting these boundary conditions a multitude of different processes and related research questions can be investigated using a variety of experimental setups. Apart from the ability to effectively control the individual boundary conditions, the main advantage of column experiments compared to other experimental setups (such as those used in field experiments, or in batch microcosm experiments) is that conservative and reactive solute breakthrough curves can be derived, which represent the sum of the transport processes. There are well-established methods for analyzing these curves. The effects observed in column studies are often a result of dynamic, non-equilibrium processes. Time (or flow velocity) is an important factor, in contrast to batch experiments where all processes are observed until equilibrium is reached in the substrate-solution system. Slight variations in the boundary conditions of different experiments can have a marked influence on the transport and degradation of organic micropollutants. This is of critical importance when comparing general results from different column experiments investigating the transport behavior of a specific organic compound. Such variations unfortunately mean that the results from most column experiments are not transferable to other hydrogeochemical environments but are only valid for the specific experimental setup used. Column experiments are fast, flexible, and easy to manage; their boundary conditions can be controlled and they are cheap compared to extensive field experiments. They can provide good estimates of all relevant transport parameters. However, the obtained results will almost always be limited to the scale of the experiment and are not directly transferrable to field scales as too many parameters are exclusive to the column setup. The challenge for the future is to develop standardized column experiments on organic micropollutants in order to overcome these issues.

COLUMN EXPERIMENTS AND ANOMALOUS CONDUCTIVITY IN HYDROCARBON-IMPACTED SOILS

EPA Science Inventory

A laboratory experiment was designed to increase the understanding of the geoelectric effects of microbial " degradation of hydrocarbons. Eight large columns were were paired to provide a replicate of each of four experiments. These large-volume columns contained "sterilized" soi...

Atmospheric Sampling of Aerosols to Stratospheric Altitudes using High Altitude Balloons

NASA Astrophysics Data System (ADS)

Jerde, E. A.; Thomas, E.

2010-12-01

Although carbon dioxide represents a long-lived atmospheric component relevant to global climate change, it is also understood that many additional contributors influence the overall climate of Earth. Among these, short-lived components are more difficult to incorporate into models due to uncertainties in the abundances of these both spatially and temporally. Possibly the most significant of these short-lived components falls under the heading of “black carbon” (BC). There are numerous overlapping definitions of BC, but it is basically carbonaceous in nature and light absorbing. Due to its potential as a climate forcer, an understanding of the BC population in the atmosphere is critical for modeling of radiative forcing. Prior measurements of atmospheric BC generally consist of airplane- and ground-based sampling, typically below 5000 m and restricted in time and space. Given that BC has a residence time on the order of days, short-term variability is easily missed. Further, since the radiative forcing is a result of BC distributed through the entire atmospheric column, aircraft sampling is by definition incomplete. We are in the process of planning a more comprehensive sampling of the atmosphere for BC using high-altitude balloons. Balloon-borne sampling is a highly reliable means to sample air through the entire troposphere and into the lower stratosphere. Our system will incorporate a balloon and a flight train of two modules. One module will house an atmospheric sampler. This sampler will be single-stage (samples all particle sizes together), and will place particles directly on an SEM sample stub for analysis. The nozzle depositing the sample will be offset from the center of the stub, placing the aerosol particles toward the edge. At various altitudes, the stub will be rotated 45 degrees, providing 6-8 sample “cuts” of particle populations through the atmospheric column. The flights will reach approximately 27 km altitude, above which the balloons burst and the modules return to the surface. The second module will contain instrumentation recording temperature, pressure, and humidity, plus a radio beacon to track the location, facilitating recovery. Another instrument we are planning is a small, lightweight optical aerosol spectrometer probe. This would provide a valuable secondary set of data to compare with the actual sampling. The aerosol particle population will be assessed using the SEM at Morehead State University. Over the next several years, sampling is planned at locations both near and far from urban areas, and at intermediate locations. Sampling will be conducted at four times during the year to assess seasonal variations and, at some sites, repeated short-term samplings (e.g., 5 flights in 10 days) will be undertaken to assess short-term variations. In addition, the SEM should permit the assessment of the ratio of BC to organic carbon (OC). Like BC, organic carbon species are produced through biomass burning, but are not as effective as light absorbers, so are not responsible for as much forcing as black carbon. The atmosphere is sampled at a known volumetric rate, resulting in a picture of the atmospheric column density for both BC and OC, information of great use in modeling of the aerosol contribution to climate change.

The Benefits of Mouse Keeping—an Empirical Study on Students' Flow and Intrinsic Motivation in Biology Lessons

NASA Astrophysics Data System (ADS)

Meyer, Annika; Klingenberg, Konstantin; Wilde, Matthias

2016-02-01

Contact with living animals is an exceptional possibility within biology education to facilitate an intense immersion into the study topic and even allow for a flow experience (Csikszentmihalyi 2000). Further, it might affect the perceptions of the students' basic needs for autonomy and competence and thereby their quality of motivation (Deci and Ryan 1985, 2002). Still, there is little empirical evidence about the duration of the exposure with living animals that is required. We investigated the students' flow experience, and the students' motivation, reported retrospectively in three different treatments: lessons involving short-term or long-term contact with living harvest mice and a control group without living animals. Our sample consisted of 156 fifth graders (10.76 years, SD = 0.513). The test instruments were adapted versions of the Flow Short Scale (FSS, Rheinberg et al. 2003) and of the Intrinsic Motivation Inventory (IMI, Ryan 1982). As expected, the control group produced significantly lower scores for both FSS and IMI. In addition, we found a significant difference between students with short-term versus long-term contact. Whereas the flow experience was indistinguishable for all pupils who had contact with living animals, those with long-term experience reported significantly higher intrinsic motivation.

Drinking High Amounts of Alcohol as a Short-Term Mating Strategy: The Impact of Short-Term Mating Motivations on Young Adults' Drinking Behavior.

PubMed

Vincke, Eveline

2017-01-01

Previous research indicates that drinking large quantities of alcohol could function as a short-term mating strategy for young adults in mating situations. However, no study investigated whether this is actually the case. Therefore, in this article, the link between short-term mating motivations and drinking high amounts of alcohol is tested. First, a survey study ( N = 345) confirmed that young adults who engage in binge drinking are more short-term oriented in their mating strategy than young adults who never engage in binge drinking. Also, the more short-term-oriented young adults were in their mating strategy, the more often binge drinking behavior was conducted. In addition, an experimental study ( N = 229) empirically verified that short-term mating motivations increase young adults' drinking behavior, more so than long-term mating motivations. Results of the experiment clearly showed that young men and young women are triggered to drink more alcoholic beverages in a short-term mating situation compared to a long-term mating situation. Furthermore, the mating situation also affected young adults' perception of drinking behavior. Young adults in a short-term mating context perceived a higher amount of alcoholic beverages as heavy drinking compared to peers in a long-term mating context. These findings confirm that a high alcohol consumption functions as a short-term mating strategy for both young men and young women. Insights gained from this article might be of interest to institutions aimed at targeting youth alcohol (ab)use.

Repeatability of the efficiency of columns packed with sub-3μm core-shell particles: Part III. 2.7μm Poroshell 120 EC-C18 particles in 4.6mm and 2.1mm × 100mm column formats.

PubMed

Gritti, Fabrice; Guiochon, Georges

2012-08-24

As part of an investigation of the column-to-column repeatability of the efficiency of columns packed with sub-3μm shell particles, the parameters of the mass transfer kinetics of twelve columns packed with the same batch of 2.7μm Poroshell 120 EC-C(18) particles (Agilent Technologies, Little Fall, DE, USA) were sequentially measured, using columns provided by the manufacturers that were representative of the efficiency distribution given by the quality test control. The reduced longitudinal diffusion term (B) was measured using the peak parking (PP) method; the reduced solid-liquid mass transfer resistance term (C) was given by a combination of the PP results and the most accurate model of effective diffusion in ternary composite materials. The overall eddy diffusion term (A) was obtained by subtraction of these two HETP terms from the overall reduced HETP derived from the peak moments measured by numerical integration of the entire peak profiles. The results demonstrate that the dispersion of the column efficiencies is a result of the random nature of the packing process and the eddy diffusion term resulting from the lack of homogeneity of the column bed. At the highest reduced velocity achieved for small analytes, the relative standard deviations (RSD) of the eddy diffusion term for the 2.1mm I.D. columns were ca. 3 and 11% (with average values h(eddy)= 2.5 and 13.5) for naphthalene (k=3) and uracil (k=0), respectively. For the 4.6mm I.D. columns, these RSDs were 5 and 13%, respectively, with average values h(eddy)= 1.4 and 2.9. For insulin at reduced velocities as high as 160, the RSDs of the total reduced plate heights were 3 and 8% for the 2.1 and 4.6mm I.D. columns, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

Study of axial mixing, holdup and slip velocity of dispersed phase in a pulsed sieve plate extraction column using radiotracer technique.

PubMed

Ghiyas Ud Din; Imran Rafiq Chughtai; Hameed Inayat, Mansoor; Hussain Khan, Iqbal

2009-01-01

Axial mixing, holdup and slip velocity of dispersed phase which are parameters of fundamental importance in the design and operation of liquid-liquid extraction pulsed sieve plate columns have been investigated. Experiments for residence time distribution (RTD) analysis have been carried out for a range of pulsation frequency and amplitude in a liquid-liquid extraction pulsed sieve plate column with water as dispersed and kerosene as continuous phase using radiotracer technique. The column was operated in emulsion region and (99m)Tc in the form of sodium pertechnetate eluted from a (99)Mo/(99m)Tc generator was used to trace the dispersed phase. Axial dispersed plug flow model with open-open boundary condition and two points measurement method was used to simulate the hydrodynamics of dispersed phase. It has been observed that the axial mixing and holdup of dispersed phase increases with increase in pulsation frequency and amplitude until a maximum value is achieved while slip velocity decreases with increase in pulsation frequency and amplitude until it approaches a minimum value. Short lived and low energy radiotracer (99m)Tc in the form of sodium pertechnetate was found to be a good water tracer to study the hydrodynamics of a liquid-liquid extraction pulsed sieve plate column operating with two immiscible liquids, water and kerosene. Axial dispersed plug flow model with open-open boundary condition was found to be a suitable model to describe the hydrodynamics of dispersed phase in the pulsed sieve plate extraction column.

Grassland responses to increased rainfall depend on the timescale of forcing.

PubMed

Sullivan, Martin J P; Thomsen, Meredith A; Suttle, K B

2016-04-01

Forecasting impacts of future climate change is an important challenge to biologists, both for understanding the consequences of different emissions trajectories and for developing adaptation measures that will minimize biodiversity loss. Existing variation provides a window into the effects of climate on species and ecosystems, but in many places does not encompass the levels or timeframes of forcing expected under directional climatic change. Experiments help us to fill in these uncertainties, simulating directional shifts to examine outcomes of new levels and sustained changes in conditions. Here, we explore the translation between short-term responses to climate variability and longer-term trajectories that emerge under directional climatic change. In a decade-long experiment, we compare effects of short-term and long-term forcings across three trophic levels in grassland plots subjected to natural and experimental variation in precipitation. For some biological responses (plant productivity), responses to long-term extension of the rainy season were consistent with short-term responses, while for others (plant species richness, abundance of invertebrate herbivores and predators), there was pronounced divergence of long-term trajectories from short-term responses. These differences between biological responses mean that sustained directional changes in climate can restructure ecological relationships characterizing a system. Importantly, a positive relationship between plant diversity and productivity turned negative under one scenario of climate change, with a similar change in the relationship between plant productivity and consumer biomass. Inferences from experiments such as this form an important part of wider efforts to understand the complexities of climate change responses. © 2016 John Wiley & Sons Ltd.

The Impact of International Internships and Short-Term Immersion Programs

ERIC Educational Resources Information Center

Gates, Lisa

2014-01-01

For students in U.S. higher education institutions, global learning through study abroad has become a powerful force in student cultural competence. This chapter explores the impact of international internships and other short-term immersion experiences in further developing student learning, especially with respect to their understanding of the…

The Cultural Adaptation Process during a Short-Term Study Abroad Experience in Swaziland

ERIC Educational Resources Information Center

Conner, Nathan W.; Roberts, T. Grady

2015-01-01

Globalization continuously shapes our world and influences post-secondary education. This study explored the cultural adaptation process of participants during a short-term study abroad program. Participants experienced stages which included initial feelings, cultural uncertainty, cultural barriers, cultural negativity, academic and career growth,…

Short-term retention of pictures and words: evidence for dual coding systems.

PubMed

Pellegrino, J W; Siegel, A W; Dhawan, M

1975-03-01

The recall of picture and word triads was examined in three experiments that manipulated the type of distraction in a Brown-Peterson short-term retention task. In all three experiments recall of pictures was superior to words under auditory distraction conditions. Visual distraction produced high performance levels with both types of stimuli, whereas combined auditory and visual distraction significantly reduced picture recall without further affecting word recall. The results were interpreted in terms of the dual coding hypothesis and indicated that pictures are encoded into separate visual and acoustic processing systems while words are primarily acoustically encoded.

Experimental study of biological effects of leads and aluminum following oral administration.

PubMed Central

Krasovskiĭ, G N; Vasukovich, L Y; Chariev, O G

1979-01-01

A wide spectrum of the biological effects of lead and aluminum ions is noted during short-term and long-term oral administration to laboratory animals. The general toxic and gonadotoxic effects of these metals during a short-term experiment appeared to be identical, and the correlation of these effects was preserved during chronic experiments. Lead (0.03 mg/l.) and aluminum (0.5 mg/l.) concentrations in water may be dangerous to the health of the population, and hygienic standards are recommended for inclusion in the standard for drinking water quality. PMID:446457

Short-term memory for order but not for item information is impaired in developmental dyslexia.

PubMed

Hachmann, Wibke M; Bogaerts, Louisa; Szmalec, Arnaud; Woumans, Evy; Duyck, Wouter; Job, Remo

2014-07-01

Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short- to long-term memory (Szmalec et al. Journal of Experimental Psychology: Learning, Memory, & Cognition 37(5): 1270-1279, 2011). At the same time, models of short-term memory increasingly incorporate a distinction of order and item processing (Majerus et al. Cognition 107: 395-419, 2008). The current study is aimed to investigate whether serial order processing deficiencies in dyslexia can be traced back to a selective impairment of short-term memory for serial order and whether this impairment also affects processing beyond the verbal domain. A sample of 26 adults with dyslexia and a group of age and IQ-matched controls participated in a 2 × 2 × 2 experiment in which we assessed short-term recognition performance for order and item information, using both verbal and nonverbal material. Our findings indicate that, irrespective of the type of material, participants with dyslexia recalled the individual items with the same accuracy as the matched control group, whereas the ability to recognize the serial order in which those items were presented appeared to be affected in the dyslexia group. We conclude that dyslexia is characterized by a selective impairment of short-term memory for serial order, but not for item information, and discuss the integration of these findings into current theoretical views on dyslexia and its associated dysfunctions.

Implicit short- and long-term memory direct our gaze in visual search.

PubMed

Kruijne, Wouter; Meeter, Martijn

2016-04-01

Visual attention is strongly affected by the past: both by recent experience and by long-term regularities in the environment that are encoded in and retrieved from memory. In visual search, intertrial repetition of targets causes speeded response times (short-term priming). Similarly, targets that are presented more often than others may facilitate search, even long after it is no longer present (long-term priming). In this study, we investigate whether such short-term priming and long-term priming depend on dissociable mechanisms. By recording eye movements while participants searched for one of two conjunction targets, we explored at what stages of visual search different forms of priming manifest. We found both long- and short- term priming effects. Long-term priming persisted long after the bias was present, and was again found even in participants who were unaware of a color bias. Short- and long-term priming affected the same stage of the task; both biased eye movements towards targets with the primed color, already starting with the first eye movement. Neither form of priming affected the response phase of a trial, but response repetition did. The results strongly suggest that both long- and short-term memory can implicitly modulate feedforward visual processing.

On the compatibility of Brewer total column ozone measurements in two adjacent valleys (Arosa and Davos) in the Swiss Alps

NASA Astrophysics Data System (ADS)

Stübi, René; Schill, Herbert; Klausen, Jörg; Vuilleumier, Laurent; Gröbner, Julian; Egli, Luca; Ruffieux, Dominique

2017-11-01

The Arosa site is well known in the ozone community for its continuous total ozone column observations that have been recorded since 1926. Originally based on Dobson sun spectrophotometers, the site has been gradually complemented by three automatic Brewer instruments, in operation since 1998. To secure the long-term ozone monitoring in this Alpine region and to benefit from synergies with the World Radiation Center, the feasibility of moving this activity to the nearby site at Davos (aerial distance of 13 km) has been explored. Concerns about a possible rupture of the 90-year-long record has motivated a careful comparison of the two sites, since great attention to the data continuity and quality has always been central to the operations of the observatory at Arosa. To this end, one element of the Arosa Brewer triad has been set up at the Davos site since November 2011 to realize a campaign of parallel measurements and to study the deviations between the three Brewer instruments. The analysis of the coincident measurement shows that the differences between Arosa and Davos remain within the range of the long-term stability of the Brewer instruments. A nonsignificant seasonal cycle is observed, which could possibly be induced by a stray-light bias and the altitude difference between the two sites. These differences are shown to be lower than the short-term variability of the time series and the overall uncertainty from individual Brewer instruments and therefore are not statistically significant. It is therefore concluded that the world's longest time series of the total ozone column obtained at Arosa site could be safely extended and continued with measurements taken from instruments located at the nearby Davos site without introducing a bias to this unique record.

Energy Product Options for Eucalyptus Species Grown as Short Rotation Woody Crops

PubMed Central

Rockwood, Donald L.; Rudie, Alan W.; Ralph, Sally A.; Zhu, J.Y.; Winandy, Jerrold E.

2008-01-01

Eucalyptus species are native to Australia but grown extensively worldwide as short rotation hardwoods for a variety of products and as ornamentals. We describe their general importance with specific emphasis on existing and emerging markets as energy products and the potential to maximize their productivity as short rotation woody crops. Using experience in Florida USA and similar locations, we document their current energy applications and assess their productivity as short-term and likely long-term energy and related products. PMID:19325808

In situ colloid mobilization in Hanford sediments under unsaturated transient flow conditions: effect of irrigation pattern.

PubMed

Zhuang, Jie; McCarthy, John F; Tyner, John S; Perfect, Edmund; Flury, Markus

2007-05-01

Colloid transport may facilitate off-site transport of radioactive wastes at the Hanford site, Washington State. In this study, column experiments were conducted to examine the effect of irrigation schedule on releases of in situ colloids from two Hanford sediments during saturated and unsaturated transientflow and its dependence on solution ionic strength, irrigation rate, and sediment texture. Results show that transient flow mobilized more colloids than steady-state flow. The number of short-term hydrological pulses was more important than total irrigation volume for increasing the amount of mobilized colloids. This effect increased with decreasing ionic strength. At an irrigation rate equal to 5% of the saturated hydraulic conductivity, a transient multipulse flow in 100 mM NaNO3 was equivalent to a 50-fold reduction of ionic strength (from 100 mM to 2 mM) with a single-pulse flow in terms of their positive effects on colloid mobilization. Irrigation rate was more important for the initial release of colloids. In addition to water velocity, mechanical straining of colloids was partly responsible for the smaller colloid mobilization in the fine than in the coarse sands, although the fine sand contained much larger concentrations of colloids than the coarse sand.

Effects of Particle Size and Bubble Characteristics on Transport of Micro- and Nano-Bubbles in Saturated Porous Media

NASA Astrophysics Data System (ADS)

Hamamoto, S.; Nihei, N.; Ueda, Y.; Moldrup, P.; Nishimura, T.

2016-12-01

The micro- and nano-bubbles (MNBs) have considerable potentials for the remediation of soil contaminated by organic compounds when used in conjunction with bioremediation technology. Understanding a transport mechanism of MNBs in soils is essential to optimize remediation techniques using MNBs. In this study, column transport experiments using glass beads with different size fractions (average particles size: 0.1 mm and 0.4 mm) were conducted, where MNBs created by oxygen gas were injected to the column with different flow rates. Effects of particle size and bubble characteristics on MNB transport in porous media were investigated based on the column experiments. The results showed that attachments of MNBs were enhanced under lower flow rate. Under higher flow rate condition, there were not significant differences of MNBs transport in porous media with different particle size. A convection-dispersion model including bubble attachment, detachment, and straining terms was applied to the obtained breakthrough curves for each experiment, showing good fitness against the measured data. Further investigations will be conducted to understand bubble characteristics including bubble size and zeta potential on MNB transport in porous media. Relations between in model parameters in the transport model and physical and chemical properties in porous media and MNBs will be discussed.

Using Bayesian variable selection to analyze regular resolution IV two-level fractional factorial designs

DOE PAGES

Chipman, Hugh A.; Hamada, Michael S.

2016-06-02

Regular two-level fractional factorial designs have complete aliasing in which the associated columns of multiple effects are identical. Here, we show how Bayesian variable selection can be used to analyze experiments that use such designs. In addition to sparsity and hierarchy, Bayesian variable selection naturally incorporates heredity . This prior information is used to identify the most likely combinations of active terms. We also demonstrate the method on simulated and real experiments.

Using Bayesian variable selection to analyze regular resolution IV two-level fractional factorial designs

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

Chipman, Hugh A.; Hamada, Michael S.

Regular two-level fractional factorial designs have complete aliasing in which the associated columns of multiple effects are identical. Here, we show how Bayesian variable selection can be used to analyze experiments that use such designs. In addition to sparsity and hierarchy, Bayesian variable selection naturally incorporates heredity . This prior information is used to identify the most likely combinations of active terms. We also demonstrate the method on simulated and real experiments.

Short-term visual deprivation, tactile acuity, and haptic solid shape discrimination.

PubMed

Crabtree, Charles E; Norman, J Farley

2014-01-01

Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task - perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task - the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation.

Repeatability of the efficiency of columns packed with sub-3μm core-shell particles: Part II. 2.7 μm Halo-ES-Peptide-C18 particles in 4.6mm and 2.1mm×100mm column formats.

PubMed

Gritti, Fabrice; Guiochon, Georges

2012-08-24

The column-to-column repeatability of the mass transfer kinetics in columns packed with sub-3μm shell particles was investigated. The parameters of this kinetics were measured for twelve columns (six 2.1mm×100mm and six 4.6mm×100mm) packed with the same batch of 2.7μm Halo-ES-Peptide-C(18) particles (Advanced Material Technologies, Wilmington, DE, USA). For both series, the manufacturer provided columns at different positions in the efficiency distribution given by the quality test control. Three compounds were used, uracil, naphthalene and insulin. The reduced longitudinal diffusion term was measured with the peak parking (PP) method; the reduced solid-liquid mass transfer resistance term was given by a combination of the PP results and the most accurate model of effective diffusion in ternary composite materials (non-porous cores, concentric porous shell, and eluent matrix), validated previously. The overall eddy diffusion term was obtained by subtraction of these two HETP terms from the overall reduced HETP measured by numerical integration of the entire peak profiles. The results demonstrate that the dispersion of the column efficiencies is mostly due to the random nature of the packing process and the associated eddy diffusion term. At the highest reduced velocity achieved, the relative standard deviations (RSDs) of the eddy diffusion term for the 2.1mm I.D. columns were ca. 5 and 10% (with average values A(ν)=2.3 and 8.5) for naphthalene and uracil, respectively. For the 4.6mm I.D. columns, these RSDs were 3 and 5%, respectively, with average values A(ν)=1.5 and 2.7. Copyright © 2012 Elsevier B.V. All rights reserved.

On the vanishing of the t-term in the short-time expansion of the diffusion coefficient for oscillating gradients in diffusion NMR

NASA Astrophysics Data System (ADS)

Laun, Frederik B.; Demberg, Kerstin; Nagel, Armin M.; Uder, Micheal; Kuder, Tristan A.

2017-11-01

Nuclear magnetic resonance (NMR) diffusion measurements can be used to probe porous structures or biological tissues by means of the random motion of water molecules. The short-time expansion of the diffusion coefficient in powers of sqrt(t), where t is the diffusion time related to the duration of the diffusion-weighting magnetic field gradient profile, is universally connected to structural parameters of the boundaries restricting the diffusive motion. The sqrt(t)-term is proportional to the surface to volume ratio. The t-term is related to permeability and curvature. The short time expansion can be measured with two approaches in NMR-based diffusion experiments: First, by the use of diffusion encodings of short total duration and, second, by application of oscillating gradients of long total duration. For oscillating gradients, the inverse of the oscillation frequency becomes the relevant time scale. The purpose of this manuscript is to show that the oscillating gradient approach is blind to the t-term. On the one hand, this prevents fitting of permeability and curvature measures from this term. On the other hand, the t-term does not bias the determination of the sqrt(t)-term in experiments.

A fundamental study of gas formation and migration during leakage of stored carbon dioxide in subsurface formations

NASA Astrophysics Data System (ADS)

Sakaki, T.; Plampin, M. R.; Lassen, R. N.; Pawar, R. J.; Komatsu, M.; Jensen, K. H.; Illangasekare, T. H.

2011-12-01

Geologic sequestration of CO2 has received significant attention as a potential method for reducing the release of greenhouse gases into the atmosphere. Potential risk of leakage of the stored CO2 to the shallow zones of the subsurface is one of the critical issues that is needed to be addressed to design effective field storage systems. If a leak occurs, gaseous CO2 reaching shallow zones of the subsurface can potentially impact the surface and groundwater sources and vegetation. With a goal of developing models that can predict these impacts, a research study is underway to improve our understanding of the fundamental processes of gas-phase formation and multi-phase flow dynamics during CO2 migration in shallow porous media. The approach involves conducting a series of highly controlled experiments in soil columns and tanks to study the effects of soil properties, temperature, pressure gradients and heterogeneities on gas formation and migration. This paper presents the results from a set of column studies. A 3.6m long column was instrumented with 16 soil moisture sensors, 15 of which were capable of measuring electrical conductivity (EC) and temperature, eight water pressure, and two gas pressure sensors. The column was filled with test sands with known hydraulic and retention characteristics with predetermined packing configurations. Deionized water saturated with CO2 under ~0.3 kPa (roughly the same as the hydrostatic pressure at the bottom of the column) was injected at the bottom of the column using a peristaltic pump. Water and gas outflow at the top of the column were monitored continuously. The results, in general, showed that 1) gas phase formation can be triggered by multiple factors such as water pressure drop, temperature rise, and heterogeneity, 2) transition to gas phase tends to occur rather within a short period of time, 3) gas phase fraction was as high as ~40% so that gas flow was not via individual bubble movement but two-phase flow, 4) water outflow that was initially equal to the inflow rate increased when gas-phase started to form (i.e., water gets displaced), and 5) gas starts to flow upward after gas phase fraction stabilizes (i.e., buoyant force overcomes). These results suggest that the generation and migration processes of gas phase CO2 can be modelled as a traditional two-phase flow with source (when CO2 gas exsolved due to complex factors) as well as sink (when gas dissolved) terms. The experimental data will be used to develop and test the conceptual models that will guide the development of numerical simulators for applications involving CO2 storage and leakage.

The Transition of Atmospheric Infrared Sounder Total Ozone Products to Operations

NASA Technical Reports Server (NTRS)

Berndt, E. B.; Zavodsky, B. T.; Jedlovec, G. J.

2014-01-01

The National Aeronautics and Space Administration Short-term Prediction Research and Transition Center (NASA SPoRT) has transitioned a total column ozone product from the Atmospheric Infrared Sounder (AIRS) retrievals to the Weather Prediction Center and Ocean Prediction Center. The total column ozone product is used to diagnose regions of warm, dry, ozone-rich, stratospheric air capable of descending to the surface to create high-impact non-convective winds. Over the past year, forecasters have analyzed the Red, Green, Blue (RGB) Air Mass imagery in conjunction with the AIRS total column ozone to aid high wind forecasts. One of the limitations of the total ozone product is that it is difficult for forecasters to determine whether elevated ozone concentrations are related to stratospheric air or climatologically high values of ozone in certain regions. During the summer of 2013, SPoRT created an AIRS ozone anomaly product which calculates the percent of normal ozone based on a global stratospheric ozone mean climatology. With the knowledge that ozone values 125 percent of normal and greater typically represent stratospheric air; the anomaly product can be used with the total column ozone product to confirm regions of stratospheric air. This paper describes the generation of these products along with forecaster feedback concerning the use of the AIRS ozone products in conjunction with the RGB Air Mass product to access the utility and transition of the products.

The cost of absenteeism and short-term disability associated with colorectal cancer: a case-control study.

PubMed

Yaldo, Avin; Seal, Brian S; Lage, Maureen J

2014-08-01

Examine the incremental impact of absenteeism and short-term disability associated with colorectal cancer (CRC). Absenteeism and short-term disability data were used for a case-control analysis of a healthy cohort (controls) compared with CRC patients (cases). Cases were matched to controls on the basis of age, sex, and region of residence. Multivariate regression models examined the costs of absenteeism and short-term disability, controlling for patient characteristics, prior medical costs, and patient general health. Compared with controls, CRC patients experience significantly higher short-term disability costs (mean, $45,716 vs $7367 [P < 0.0001]; median, $35,827 vs $7365 [P < 0.0001]), as well as significantly higher absenteeism costs (mean, $8841 vs $4596 [P < 0.0001]; median, $9971 vs $4795 [P < 0.0001]) in the 1 year after diagnosis of CRC. Colorectal cancer is associated with significant work-related productivity loss costs in the first year after diagnosis.

Metal releases from a municipal solid waste incineration air pollution control residue mixed with compost.

PubMed

Van Praagh, M; Persson, K M

2008-08-01

The influence of 10 wt.% mature compost was tested on the heavy metal leachate emissions from a calcium-rich municipal solid waste incineration air pollution control residue (MSWI APC). Apart from elongated columns (500 and 1250 mm), an otherwise norm compliant European percolation test setup was used. More than 99% of the metals Al, As, Cd, Cr, Cu, Fe and Ni were left in the APC residue after leaching to a liquid-to-solid ratio (L/S) of 10. Apparent short-term effects of elevated leachate DOC concentrations on heavy metal releases were not detected. Zn and Pb leachate concentrations were one order of magnitude lower for L/S 5 and 10 from the pure APC residue column, which suggests a possible long-term effect of compost on the release of these elements. Prolonging the contact time between the pore water and the material resulted in elevated leachate concentrations at L/S 0.1 to L/S 1 by a factor of 2. Only Cr and Pb concentrations were at their maxima in the first leachates at L/S 0.1. Equilibrium speciation modelling with the PHREEQC code suggested portlandite (Ca(OH)2) to control Ca solubility and pH.

Titanium-scaffolded organic-monolithic stationary phases for ultra-high-pressure liquid chromatography.

PubMed

Vonk, Rudy J; Vaast, Axel; Eeltink, Sebastiaan; Schoenmakers, Peter J

2014-09-12

Organic-polymer monoliths with overall dimensions larger than one millimetre are prone to rupture - either within the monolith itself or between the monoliths and the containing wall - due to the inevitable shrinkage accompanying the formation of a cross-linked polymeric network. This problem has been addressed by creating titanium-scaffolded poly(styrene-co-divinylbenzene) (S-co-DVB) monoliths. Titanium-scaffolded monoliths were successfully used in liquid chromatography at very high pressures (up to 80MPa) and using gradients spanning the full range of water-acetonitrile compositions (0 to 100%). The kinetic-performance of (50-mm long) titanium-scaffolded monoliths was compared to that of similar monolith created in 1-mm i.d. glass-lined tubing at pressures up to 50MPa. The peak capacities obtained with the titanium-scaffolded column was about 30% lower. An increased Eddy-diffusion, due to the pillar-structure, and a decreased permeability are thought to be the main reasons for this reduced kinetic-performance. No decrease in performance was observed when the titanium-scaffolded columns were operated at pressures of 80MPa for up to 12h. The column-to-column repeatability (n=5) was acceptable in terms of observed peak widths at half heights (RSD ca. 10%) The run-to-run repeatability (n=135) in terms of retention times and peak widths at half height were found to be good. Titanium-scaffolded columns coupled in series up to a combined length of (200mm) were used for the analyses of a complex Escherichia coli protein sample. Our experiments demonstrate that columns based on titanium-scaffolded organic-polymer monolith can be operated under strenuous conditions without loss in performance. The titanium-scaffolded approach makes it feasible to create organic-polymer monoliths in wide-bore columns with accurate temperature control. Copyright © 2014 Elsevier B.V. All rights reserved.

Are the spring and fall blooms on the Scotian Shelf related to short-term physical events?

NASA Astrophysics Data System (ADS)

Greenan, B. J. W.; Petrie, B. D.; Harrison, W. G.; Oakey, N. S.

2004-03-01

Physical, chemical and biological data from the Scotian Shelf indicate that short-term physical events affect the dynamics of spring and fall blooms. This is based on results from a three-week mooring deployment measuring currents, temperature, salinity and fluorescence in October 2000, combined with biweekly sampling of temperature, salinity, nutrients and chlorophyll throughout the year at this mooring site. A wind-driven upwelling event in mid-October shows temperature, salinity and density iso-surfaces rising by approximately 20 m. During this event, a bloom with peak chlorophyll concentrations of about 2.5 mg m -3 began as nutrients are brought into the upper part of the water column. Gradient Richardson Numbers ( Ri), a proxy for vertical mixing, are estimated for the mooring period in 2 m vertical bins using SeaHorse CTD data and nearby ADCP current measurements. These data indicate that vertical mixing may have played a complementary role to the upwelling in bringing nutrients into the euphotic zone. A trend of decreasing Ri in the ocean mixed layer with increasing surface wind stress is suggested. It appears that this short-term physical event is a primary factor in initiating the fall bloom on the inner Scotian Shelf in 2000. In April of that year, the termination of the spring bloom coincided with a downwelling event suggesting that it played a role in determining the duration of the bloom. SeaWiFS ocean color satellite provided a spatial context for chlorophyll observations, however, the lack of temporal resolution due to poor atmospheric conditions means that these data provide limited information on short-term chlorophyll variability.

The roles of long-term phonotactic and lexical prosodic knowledge in phonological short-term memory.

PubMed

Tanida, Yuki; Ueno, Taiji; Lambon Ralph, Matthew A; Saito, Satoru

2015-04-01

Many previous studies have explored and confirmed the influence of long-term phonological representations on phonological short-term memory. In most investigations, phonological effects have been explored with respect to phonotactic constraints or frequency. If interaction between long-term memory and phonological short-term memory is a generalized principle, then other phonological characteristics-that is, suprasegmental aspects of phonology-should also exert similar effects on phonological short-term memory. We explored this hypothesis through three immediate serial-recall experiments that manipulated Japanese nonwords with respect to lexical prosody (pitch-accent type, reflecting suprasegmental characteristics) as well as phonotactic frequency (reflecting segmental characteristics). The results showed that phonotactic frequency affected the retention not only of the phonemic sequences, but also of pitch-accent patterns, when participants were instructed to recall both the phoneme sequence and accent pattern of nonwords. In addition, accent pattern typicality influenced the retention of the accent pattern: Typical accent patterns were recalled more accurately than atypical ones. These results indicate that both long-term phonotactic and lexical prosodic knowledge contribute to phonological short-term memory performance.

A rapid and sensitive method for the quantitation of montelukast in sheep plasma using liquid chromatography/tandem mass spectrometry.

PubMed

Papp, Robert; Luk, Pauline; Mullett, Wayne M; Kwong, Elizabeth

2007-10-15

A rapid LC-MS/MS method was developed and partially validated for the quantitation of montelukast in spiked sheep plasma. A total run time of 1.5 min was achieved using a short monolithic column and employing a rapid gradient. Sample preparation involved protein precipitation with twofold acetonitrile by volume during which a deuterated internal standard (montelukast D-6) was incorporated. The MRM transitions for montelukast and the deuterated internal standard were 586/422 and 592/427, respectively. A linear dynamic range of 0.25-500 ng/mL with a correlation coefficient of 0.9999 was achieved. Precision was below 5% at all levels except at the LOQ (0.36 ng/mL) which demonstrated an overall of R.S.D. of 8%. Post-column infusion experiments were performed with precipitated plasma matrix and showed minimal interference with the peaks of interest.

Short-Term Missions at the Master's College: An Experiential Education

ERIC Educational Resources Information Center

La George, Lisa

2009-01-01

Foreign Missions Preparation (FMP) has been in operation at The Master's College (TMC) since 1989, employing experiential education to train and facilitate cross-cultural summer Short-Term Mission (STM) trips for over a thousand undergraduate students. The question driving the case study was: "What influence does an analysis of the experiences of…

Exogenous Attention Influences Visual Short-Term Memory in Infants

ERIC Educational Resources Information Center

Ross-Sheehy, Shannon; Oakes, Lisa M.; Luck, Steven J.

2011-01-01

Two experiments examined the hypothesis that developing visual attentional mechanisms influence infants' Visual Short-Term Memory (VSTM) in the context of multiple items. Five- and 10-month-old infants (N = 76) received a change detection task in which arrays of three differently colored squares appeared and disappeared. On each trial one square…

Processing of Formational, Semantic, and Iconic Information in American Sign Language.

ERIC Educational Resources Information Center

Poizner, Howard; And Others

1981-01-01

Three experiments examined short-term encoding processes of deaf signers for different aspects of signs from American Sign Language. Results indicated that deaf signers code signs at one level in terms of linguistically significant formational parameters. The semantic and iconic information of signs, however, has little effect on short-term…

An Electrophysiological Signature of Summed Similarity in Visual Working Memory

ERIC Educational Resources Information Center

van Vugt, Marieke K.; Sekuler, Robert; Wilson, Hugh R.; Kahana, Michael J.

2013-01-01

Summed-similarity models of short-term item recognition posit that participants base their judgments of an item's prior occurrence on that item's summed similarity to the ensemble of items on the remembered list. We examined the neural predictions of these models in 3 short-term recognition memory experiments using electrocorticographic/depth…

In Their Own Words: Assessing Global Citizenship in a Short-Term Study-Abroad Program in Bangladesh

ERIC Educational Resources Information Center

Gambino, Giacomo; Hashim, S. Mohsin

2016-01-01

The article examines whether short-term study-abroad (STSA) experiences can cultivate the cultural understandings and ethical commitments entailed by a cosmopolitan civic education. We examine students' critical reflections on their participation in a two-week study-abroad program titled "Climate Change and Sustainable Development in…

Verbal Short-Term Memory Performance in Pupils with Down Syndrome

ERIC Educational Resources Information Center

Abdelhameed, Hala; Porter, Jill

2010-01-01

Research has shown that verbal short-term memory span is shorter in individuals with Down syndrome than in typically developing individuals of equivalent mental age, but little attention has been given to variations within or across groups. Differences in the environment and in particular educational experiences may play a part in the relative…

Dialogue Journals in Short-Term Study Abroad: "Today I Wrote My Mind"

ERIC Educational Resources Information Center

Dressler, Roswita; Tweedie, M. Gregory

2016-01-01

Short-term study abroad programs are growing in popularity, and educators and researchers are exploring effective tools to enhance the learning and cultural experiences of students in these programs. Dialogue journals, writing journals in which students respond to instructor prompts and in turn initiate topics for further written discussion, are a…

Bacteriophage PRD1 batch experiments to study attachment, detachment and inactivation processes

NASA Astrophysics Data System (ADS)

Sadeghi, Gholamreza; Schijven, Jack F.; Behrends, Thilo; Hassanizadeh, S. Majid; van Genuchten, Martinus Th.

2013-09-01

Knowledge of virus removal in subsurface environments is pivotal for assessing the risk of viral contamination of water resources and developing appropriate protection measures. Columns packed with sand are frequently used to quantify attachment, detachment and inactivation rates of viruses. Since column transport experiments are very laborious, a common alternative is to perform batch experiments where usually one or two measurements are done assuming equilibrium is reached. It is also possible to perform kinetic batch experiments. In that case, however, it is necessary to monitor changes in the concentration with time. This means that kinetic batch experiments will be almost as laborious as column experiments. Moreover, attachment and detachment rate coefficients derived from batch experiments may differ from those determined using column experiments. The aim of this study was to determine the utility of kinetic batch experiments and investigate the effects of different designs of the batch experiments on estimated attachment, detachment and inactivation rate coefficients. The experiments involved various combinations of container size, sand-water ratio, and mixing method (i.e., rolling or tumbling by pivoting the tubes around their horizontal or vertical axes, respectively). Batch experiments were conducted with clean quartz sand, water at pH 7 and ionic strength of 20 mM, and using the bacteriophage PRD1 as a model virus. Values of attachment, detachment and inactivation rate coefficients were found by fitting an analytical solution of the kinetic model equations to the data. Attachment rate coefficients were found to be systematically higher under tumbling than under rolling conditions because of better mixing and more efficient contact of phages with the surfaces of the sand grains. In both mixing methods, more sand in the container yielded higher attachment rate coefficients. A linear increase in the detachment rate coefficient was observed with increased solid-water ratio using tumbling method. Given the differences in the attachment rate coefficients, and assuming the same sticking efficiencies since chemical conditions of the batch and column experiments were the same, our results show that collision efficiencies of batch experiments are not the same as those of column experiments. Upscaling of the attachment rate from batch to column experiments hence requires proper understanding of the mixing conditions. Because batch experiments, in which the kinetics are monitored, are as laborious as column experiments, there seems to be no major advantage in performing batch instead of column experiments.

Impaired verbal short-term memory in Down syndrome reflects a capacity limitation rather than atypically rapid forgetting.

PubMed

M Purser, Harry R; Jarrold, Christopher

2005-05-01

Individuals with Down syndrome suffer from relatively poor verbal short-term memory. Recent work has indicated that this deficit is not caused by problems of audition, speech, or articulatory rehearsal within the phonological loop component of Baddeley and Hitch's working memory model. Given this, two experiments were conducted to investigate whether abnormally rapid decay underlies the deficit. In a first experiment, we attempted to vary the time available for decay using a modified serial recall procedure that had both verbal and visuospatial conditions. No evidence was found to suggest that forgetting is abnormally rapid in phonological memory in Down syndrome, but a selective phonological memory deficit was indicated. A second experiment further investigated possible problems of decay in phonological memory, restricted to item information. The results indicated that individuals with Down syndrome do not show atypically rapid item forgetting from phonological memory but may have a limited-capacity verbal short-term memory system.

Calculation of Centrally Loaded Thin-Walled Columns Above the Buckling Limit

NASA Technical Reports Server (NTRS)

Reinitzhuber, F.

1945-01-01

When thin-walled columns formed from flanged sheet, such as used in airplane construction, are subjected to axial load, their behavior at failure varies according to the slenderness ratio. On long columns the axis deflects laterally while the cross section form is maintained; buckling results. The respective breaking load in the elastic range is computed by Euler's formula and for the plastic range by the Engesser- Karman formula. Its magnitude is essentially dependent upon the length. On intermediate length columns, especially where open sections are concerned, the cross section is distorted while the cross section form is preserved; twisting failure results. The buckling load in twisting is calculated according to Wagner and Kappus. On short columns the straight walls of low-bending resistance that form the column are deflected at the same time that the cross section form changes - buckling occurs without immediate failure. Then the buckling load of the total section computable from the buckling loads of the section walls is not the ultimate load; quite often, especially on thin-walled sections, it lies considerably higher and is secured by tests. Both loads, the buckling and the ultimate load are only in a small measure dependent upon length. The present report is an attempt to theoretically investigate the behavior of such short, thin-walled columns above the buckling load with the conventional calculating methods.

Pupil old/new effects reflect stimulus encoding and decoding in short-term memory.

PubMed

Brocher, Andreas; Graf, Tim

2016-12-01

We conducted five pupil old/new experiments to examine whether pupil old/new effects can be linked to familiarity and/or recollection processes of recognition memory. In Experiments 1-3, we elicited robust pupil old/new effects for legal words and pseudowords (Experiment 1), positive and negative words (Experiment 2), and low-frequency and high-frequency words (Experiment 3). Importantly, unlike for old/new effects in ERPs, we failed to find any effects of long-term memory representations on pupil old/new effects. In Experiment 4, using the words and pseudowords from Experiment 1, participants made lexical decisions instead of old/new decisions. Pupil old/new effects were restricted to legal words. Additionally requiring participants to make speeded responses (Experiment 5) led to a complete absence of old/new effects. Taken together, these data suggest that pupil old/new effects do not map onto familiarity and recollection processes of recognition memory. They rather seem to reflect strength of memory traces in short-term memory, with little influence of long-term memory representations. Crucially, weakening the memory trace through manipulations in the experimental task significantly reduces pupil/old new effects. © 2016 Society for Psychophysiological Research.

Short and Sweet: The Persuasive Effects of Message Framing and Temporal Context in Antismoking Warning Labels.

PubMed

Mollen, Saar; Engelen, Susanne; Kessels, Loes T E; van den Putte, Bas

2017-01-01

Current warning labels on cigarette packages are generally focused on long-term losses that can be incurred if one continues smoking. This study compares the effects of these labels against warning labels that stress short-term losses of smoking as well as labels that stress short- and long-term benefits that can be obtained when one quits smoking. A 2 (message frame: gain vs. loss) × 2 (temporal context: short vs. long term) between-subjects experiment was conducted among 132 smokers, with attitude toward quitting smoking and intention to quit smoking, as well as information-seeking behavior and message recall, as the dependent variables. Findings were in line with theory regarding message framing and temporal discounting, showing enhanced effects of gain over loss frames and short-term over long-term consequences on warning labels for attitudes and intentions. In addition, an interaction between message frame and temporal context was found. Especially, gain-framed messages showed stronger effects on intentions to quit smoking than loss-framed messages when warning labels concerned short-term outcomes. Findings suggest that current warning labels, with an emphasis on long-term negative health outcomes, should be reconsidered.

Measurement of the eddy diffusion term in chromatographic columns. I. Application to the first generation of 4.6mm I.D. monolithic columns.

PubMed

Gritti, Fabrice; Guiochon, Georges

2011-08-05

The corrected heights equivalent to a theoretical plate (HETP) of three 4.6mm I.D. monolithic Onyx-C(18) columns (Onyx, Phenomenex, Torrance, CA) of different lengths (2.5, 5, and 10 cm) are reported for retained (toluene, naphthalene) and non-retained (uracil, caffeine) small molecules. The moments of the peak profiles were measured according to the accurate numerical integration method. Correction for the extra-column contributions was systematically applied. The peak parking method was used in order to measure the bulk diffusion coefficients of the sample molecules, their longitudinal diffusion terms, and the eddy diffusion term of the three monolithic columns. The experimental results demonstrate that the maximum efficiency was 60,000 plates/m for retained compounds. The column length has a large impact on the plate height of non-retained species. These observations were unambiguously explained by a large trans-column eddy diffusion term in the van Deemter HETP equation. This large trans-rod eddy diffusion term is due to the combination of a large trans-rod velocity bias (≃3%), a small radial dispersion coefficient in silica monolithic columns, and a poorly designed distribution and collection of the sample streamlets at the inlet and outlet of the monolithic rod. Improving the performance of large I.D. monolithic columns will require (1) a detailed knowledge of the actual flow distribution across and along these monolithic rod and (2) the design of appropriate inlet and outlet distributors designed to minimize the nefarious impact of the radial flow heterogeneity on band broadening. Copyright © 2011 Elsevier B.V. All rights reserved.

Leaching and uptake of heavy metals by ten different species of plants during an EDTA-assisted phytoextraction process.

PubMed

Chen, Yahua; Li, Xiangdong; Shen, Zhenguo

2004-10-01

In a pot experiment, the potential use of 10 plant species, including six dicotyledon species and four monocotyledon species, was investigated for the EDTA-enhanced phytoextraction of Pb from contaminated soil. Mung bean and buckwheat had a higher sensitivity to the EDTA treatment in soils. In the 2.5 and 5.0 mmol kg(-1) EDTA treatments, the Pb concentrations in the shoots of the six dicotyledon species ranged from 1,000 to 3,000 mg kg(-1) of dry matter, which were higher than those of the monocotyledon species. The highest amount of phytoextracted Pb (2.9 mg Pb pot(-1)) was achieved in sunflowers, due to the high concentration of Pb in their shoots and large biomass, followed by corns (1.8 mg Pb pot(-1)) and peas (1.1 mg Pb pot(-1)). The leaching behavior of heavy metals as a result of applying EDTA to the surface of the soil was also investigated using short soil-leaching columns (9.0-cm diameter, 20-cm height) by the percolation of artificial rainfall. About 3.5%, 15.8%, 13.7% and 20.6% of soil Pb, Cu, Zn and Cd, respectively, were leached from the soil columns after the application of 5.0 mmol kg(-1) of EDTA. The growth of sunflowers in the soil columns had little effect on the amount of metals that were leached out. This was probably due to the shallowness of the layer of soil, the short time-span of the uptake of metals by the plant and the plant's simple root systems.

Modeling of copper sorption onto GFH and design of full-scale GFH adsorbers.

PubMed

Steiner, Michele; Pronk, Wouter; Boller, Markus A

2006-03-01

During rain events, copper wash-off occurring from copper roofs results in environmental hazards. In this study, columns filled with granulated ferric hydroxide (GFH) were used to treat copper-containing roof runoff. It was shown that copper could be removed to a high extent. A model was developed to describe this removal process. The model was based on the Two Region Model (TRM), extended with an additional diffusion zone. The extended model was able to describe the copper removal in long-term experiments (up to 125 days) with variable flow rates reflecting realistic runoff events. The four parameters of the model were estimated based on data gained with specific column experiments according to maximum sensitivity for each parameter. After model validation, the parameter set was used for the design of full-scale adsorbers. These full-scale adsorbers show high removal rates during extended periods of time.

Experimental methods for studying microbial survival in extraterrestrial environments.

PubMed

Olsson-Francis, Karen; Cockell, Charles S

2010-01-01

Microorganisms can be used as model systems for studying biological responses to extraterrestrial conditions; however, the methods for studying their response are extremely challenging. Since the first high altitude microbiological experiment in 1935 a large number of facilities have been developed for short- and long-term microbial exposure experiments. Examples are the BIOPAN facility, used for short-term exposure, and the EXPOSE facility aboard the International Space Station, used for long-term exposure. Furthermore, simulation facilities have been developed to conduct microbiological experiments in the laboratory environment. A large number of microorganisms have been used for exposure experiments; these include pure cultures and microbial communities. Analyses of these experiments have involved both culture-dependent and independent methods. This review highlights and discusses the facilities available for microbiology experiments, both in space and in simulation environments. A description of the microorganisms and the techniques used to analyse survival is included. Finally we discuss the implications of microbiological studies for future missions and for space applications. Copyright 2009 Elsevier B.V. All rights reserved.

Enabling Chemistry of Gases and Aerosols for Assessment of Short-Lived Climate Forcers: Improving Solar Radiation Modeling in the DOE-ACME and CESM models

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

Prather, Michael

This proposal seeks to maintain the DOE-ACME (offshoot of CESM) as one of the leading CCMs to evaluate near-term climate mitigation. It will implement, test, and optimize the new UCI photolysis codes within CESM CAM5 and new CAM versions in ACME. Fast-J is a high-order-accuracy (8 stream) code for calculating solar scattering and absorption in a single column atmosphere containing clouds, aerosols, and gases that was developed at UCI and implemented in CAM5 under the previous BER/SciDAC grant.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

USGS Publications Warehouse

Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

1995-01-01

A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

The use of One-Dimensional Laboratory Experiments to Assess Hydraulic Processes in Wastewater Soil Absorption Systems

NASA Astrophysics Data System (ADS)

Huntzinger, D. N.; McCray, J. E.; Siegrist, R.; Lowe, K.; VanCuyk, S.

2001-05-01

Sixteen, one-dimensional column lysimeters have been developed to evaluate the influence of loading regime and infiltrative surface character on hydraulic performance in wastewater soil absorption systems. A duplicate design was utilized to evaluate two infiltrative surface conditions (gravel-free vs. gravel-laden) under four hydraulic loading regimes representative of possible field conditions. By loading the columns at rates of 25 to 200 cm/day, the 17 weeks of column operation actually reflect up to approximately 13 yrs of field operation (at 5 cm/day). Therefore, the cumulative mass throughput and infiltrative rate loss for each loading regime can be examined to determine the viability of accelerated loading as a means to compress the time scale of observation, while still producing meaningfully results for the field scale. During operation, the columns were loaded with septic tank effluent at a prescribed rate and routinely monitoring for applied effluent composition, infiltration rate, time-dependant soil water content, water volume throughput, and percolate composition. Bromide tracer tests were completed prior to system startup and at weeks 2, 6, and 17 of system operation. Hydraulic characterization of the columns is based on measurements of the hydraulic loading rate, volumetric throughput, soil water content, and bromide breakthrough curves. Incipient ponding of wastewater developed during the 1st week of operation for columns loaded at the highest hydraulic rate (loading regimes 1 and 2), and during the 3rd and 6th week of operation for loading regimes 3 and 4, respectfully. The bromide breakthrough curves exhibit later breakthrough and tailing as system life increases, indicating the development of spatially variability in hydraulic conductivity within the column and the development of a clogging zone at the infiltrative surface. Throughput is assessed for each loading regime to determine the infiltration rate loss versus days of operation. Loading regimes 1 and 2 approach a comparable long-term throughput rate less than 20 cm/day, while loading regimes 3 and 4 reach a long-term throughput rate of less than 10 cm/day. These one-dimensional columns allow for the analysis of infiltrative rate loss and hydraulic behavior as a result of infiltrative surface character and loading regime.

Can short-term and small-scale experiments reflect nutrient limitation on phytoplankton in natural lakes?

NASA Astrophysics Data System (ADS)

Wang, Haijun; Li, Yan; Feng, Weisong; Yu, Qing; Xiao, Xucheng; Liang, Xiaomin; Shao, Jianchun; Ma, Shuonan; Wang, Hongzhu

2017-05-01

Whether it is necessary to reduce nitrogen (N) and/or phosphorus (P) input to mitigate lake eutrophication is controversial. The controversy stems mainly from differences in time and space in previous studies that support the contrasting ideas. To test the response of phytoplankton to various combinations of nutrient control strategies in mesocosms and the possibility of reflecting the conditions in natural ecosystems with short-term experiments, a 9-month experiment was carried out in eight 800-L tanks with four nutrient level combinations (+N+P, -N+P, +N-P, and -N-P), with an 18-month whole-ecosystem experiment in eight 800-m 2 ponds as the reference. Phytoplankton abundance was determined by P not N, regardless of the initial TN/TP level, which was in contrast to the nutrient limitation predicted by the N/P theory. Net natural N inputs were calculated to be 4.9, 6.8, 1.5, and 3.0 g in treatments +N+P, -N+P, +N-P, and -N-P, respectively, suggesting that N deficiency and P addition may promote natural N inputs to support phytoplankton development. However, the compensation process was slow, as suggested by an observed increase in TN after 3 weeks in -N+P and 2 months in -N-P in the tank experiment, and after 3 months in -N +P and 3 months in -N-P in our pond experiment. Obviously, such a slow process cannot be simulated in short-term experiments. The natural N inputs cannot be explained by planktonic N-fixation because N-fixing cyanobacteria were scarce, which was probably because there was a limited pool of species in the tanks. Therefore, based on our results we argue that extrapolating short-term, small-scale experiments to large natural ecosystems does not give reliable, accurate results.

Short-cut Methods versus Rigorous Methods for Performance-evaluation of Distillation Configurations

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

Ramapriya, Gautham Madenoor; Selvarajah, Ajiththaa; Jimenez Cucaita, Luis Eduardo

Here, this study demonstrates the efficacy of a short-cut method such as the Global Minimization Algorithm (GMA), that uses assumptions of ideal mixtures, constant molar overflow (CMO) and pinched columns, in pruning the search-space of distillation column configurations for zeotropic multicomponent separation, to provide a small subset of attractive configurations with low minimum heat duties. The short-cut method, due to its simplifying assumptions, is computationally efficient, yet reliable in identifying the small subset of useful configurations for further detailed process evaluation. This two-tier approach allows expedient search of the configuration space containing hundreds to thousands of candidate configurations for amore » given application.« less

Short-cut Methods versus Rigorous Methods for Performance-evaluation of Distillation Configurations

DOE PAGES

Ramapriya, Gautham Madenoor; Selvarajah, Ajiththaa; Jimenez Cucaita, Luis Eduardo; ...

2018-05-17

Here, this study demonstrates the efficacy of a short-cut method such as the Global Minimization Algorithm (GMA), that uses assumptions of ideal mixtures, constant molar overflow (CMO) and pinched columns, in pruning the search-space of distillation column configurations for zeotropic multicomponent separation, to provide a small subset of attractive configurations with low minimum heat duties. The short-cut method, due to its simplifying assumptions, is computationally efficient, yet reliable in identifying the small subset of useful configurations for further detailed process evaluation. This two-tier approach allows expedient search of the configuration space containing hundreds to thousands of candidate configurations for amore » given application.« less

Comparison of Three Model Concepts for Streaming Potential in Unsaturated Porous Media

NASA Astrophysics Data System (ADS)

Huisman, J. A.; Satenahalli, P.; Zimmermann, E.; Vereecken, H.

2017-12-01

Streaming potential is the electric potential generated by fluid flow in a charged porous medium. Although streaming potential in saturated conditions is well understood, there still is considerable debate about the adequate modelling of streaming potential signals in unsaturated soil because different concepts are available to estimate the effective excess charge in unsaturated conditions. In particular, some studies have relied on the volumetric excess charge, whereas others proposed to use the flux-averaged excess charge derived from the water retention or relative permeability function. The aim of this study is to compare measured and modelled streaming potential signals for two different flow experiments with sand. The first experiment is a primary gravity drainage of a long column equipped with non-polarizing electrodes and tensiometers, as presented in several previous studies. Expected differences between the three concepts for the effective excess charge are only moderate for this set-up. The second experiment is a primary drainage of a short soil column equipped with non-polarizing electrodes and tensiometers using applied pressure, where differences between the three concepts are expected to be larger. A comparison of the experimental results with a coupled model of streaming potential for 1D flow problems will provide insights in the ability of the three model concepts for effective excess charge to describe observed streaming potentials.

Mapping Isoprene Emissions over North America using Formaldehyde Column Observations from Space

NASA Technical Reports Server (NTRS)

Palmer, Paul I.; Jacob, Daniel J.; Fiore, Arlene M.; Martin, Randall V.; Chance, Kelly; Kurosu, Thomas P.

2004-01-01

I] We present a methodology for deriving emissions of volatile organic compounds (VOC) using space-based column observations of formaldehyde (HCHO) and apply it to data from the Global Ozone Monitoring Experiment (GOME) satellite instrument over North America during July 1996. The HCHO column is related to local VOC emissions, with a spatial smearing that increases with the VOC lifetime. lsoprene is the dominant HCHO precursor over North America in summer, and its lifetime (approx. = 1 hour) is sufficiently short that the smearing can be neglected. We use the Goddard Earth Observing System global 3-D model of tropospheric chemistry (GEOS-CHEM) to derive the relationship between isoprene emissions and HCHO columns over North America and use these relationships to convert the GOME HCHO columns to isoprene emissions. We also use the GEOS-CHEM model as an intermediary to validate the GOME HCHO column measurements by comparison with in situ observations. The GEOS-CHEM model including the Global Emissions Inventory Activity (GEIA) isoprene emission inventory provides a good simulation of both the GOME data (r(sup 2) = 0.69, n = 756, bias = +l1 %) and the in situ summertime HCHO measurements over North America (r(sup 2) = 0.47, n = 10, bias = -3%). The GOME observations show high values over regions of known high isoprene emissions and a day-to-day variability that is consistent with the temperature dependence of isoprene emission. Isoprene emissions inferred from the GOME data are 20% less than GEIA on average over North America and twice those from the U S . EPA Biogenic Emissions Inventory System (BEIS2) inventory. The GOME isoprene inventory when implemented in the GEOS-CHEM model provides a better simulation of the HCHO in situ measurements thaneitherGEIAorBEIS2 (r(sup 2) = 0.71,n= 10, bias = -10 %).

The Cultural Adaptation Process of Agricultural and Life Sciences Students on Short-Term Study Abroad Experiences

ERIC Educational Resources Information Center

Conner, Nathan William

2013-01-01

The purpose of this study was to explore how undergraduate students in a college of agricultural and life sciences experienced cultural adaptation during short-term study abroad programs. The specific objectives of this study were to describe how undergraduate students in the college of agricultural and life sciences experienced culture throughout…

A Case Study of Troika Short-Term Study Abroad Program Model in Community Colleges

ERIC Educational Resources Information Center

Pickard, Jeremy L.

2010-01-01

This case study examined the phenomenon, through a basic interpretive approach, of 13 students who participated in a short-term study abroad program at a community college. Participants shared experiences from their programs that provided meaning to their lives and how that meaning has shaped their life socially, academically, professionally, and…

Spatiotemporal Proximity Effects in Visual Short-Term Memory Examined by Target-Nontarget Analysis

ERIC Educational Resources Information Center

Sapkota, Raju P.; Pardhan, Shahina; van der Linde, Ian

2016-01-01

Visual short-term memory (VSTM) is a limited-capacity system that holds a small number of objects online simultaneously, implying that competition for limited storage resources occurs (Phillips, 1974). How the spatial and temporal proximity of stimuli affects this competition is unclear. In this 2-experiment study, we examined the effect of the…

Speech, "Inner Speech," and the Development of Short-Term Memory: Effects of Picture-Labeling on Recall.

ERIC Educational Resources Information Center

Hitch, Graham J.; And Others

1991-01-01

Reports on experiments to determine effects of overt speech on children's use of inner speech in short-term memory. Word length and phonemic similarity had greater effects on older children and when pictures were labeled at presentation. Suggests that speaking or listening to speech activates an internal articulatory loop. (Author/GH)

Exposing Students to Repeat Photography: Increasing Cultural Understanding on a Short-Term Study Abroad

ERIC Educational Resources Information Center

Lemmons, Kelly K.; Brannstrom, Christian; Hurd, Danielle

2014-01-01

Traditionally, repeat photography has been used to analyze land cover change. This paper describes how repeat photography may be used as a tool to enhance the short-term study abroad experience by facilitating cultural interaction and understanding. We present evidence from two cases and suggest a five-step repeat photography method for educators…

Dissociation of Short-Term Forgetting from the Passage of Time

ERIC Educational Resources Information Center

White, K. Geoffrey

2012-01-01

In many theories, forgetting is closely linked to the passage of time. In the present experiments, recall in a short-term memory task was less accurate when the retention interval included a difficult arithmetic addition task, compared with an easy task. In a novel condition, the interfering task was switched from hard to easy partway through the…

Binding and Inhibition in Working Memory: Individual and Age Differences in Short-Term Recognition

ERIC Educational Resources Information Center

Oberauer, Klaus

2005-01-01

Two studies investigated the relationship between working memory capacity (WMC), adult age, and the resolution of conflict between familiarity and recollection in short-term recognition tasks. Experiment 1 showed a specific deficit of young adults with low WMC in rejecting intrusion probes (i.e., highly familiar probes) in a modified Sternberg…

Meta-Travel: A Critical Inquiry into a China Study Tour

ERIC Educational Resources Information Center

Riggan, Jennifer; Gwak, Sonya; Lesnick, Joy; Jackson, Kara; Olitsky, Stacey

2011-01-01

Short-term study tours are among the fastest growing of study abroad experiences and serve the largest percentage of students choosing to study abroad. Fifty-six percent of students studying abroad go on short-term study trips lasting anywhere from two to eight weeks. These trips have the advantage of being able to provide study travel experiences…

A Transformative Experience: A Short-Term Cross-Cultural Service-Learning Immersion to Kenya

ERIC Educational Resources Information Center

Kearney, Sean; Perkins, Timothy; Maakrun, Julie

2014-01-01

Initial teacher education programs are continuously looking for ways to grow and evolve to meet the changing needs of pre-service teachers (PSTs) who will face a diverse student population when they begin their careers. This study examines a short-term, cross-cultural, service-learning immersion undertaken by 21 undergraduate PSTs to an internally…

Temporal Clustering and Sequencing in Short-Term Memory and Episodic Memory

ERIC Educational Resources Information Center

Farrell, Simon

2012-01-01

A model of short-term memory and episodic memory is presented, with the core assumptions that (a) people parse their continuous experience into episodic clusters and (b) items are clustered together in memory as episodes by binding information within an episode to a common temporal context. Along with the additional assumption that information…

Eelgrass indicator deployment system (EIDS): A low tech tool for short-term evaluation of eelgrass response to water quality

EPA Science Inventory

Eelgrass is often considered a sentinel species that can be used as an indicator of water clarity and quality. I used the Eelgrass Indicator Deployment System (EIDS) in a series of short term experiments to evaluate eelgrass growth and survival at a decline and a control site in...

Internationalizing Graduate Education through Education Abroad: The Pedagogy of Short-Term, Faculty-Led, Education Abroad Experiences

ERIC Educational Resources Information Center

Loebick, Karla

2017-01-01

Internationalization efforts within higher education have been increasingly prioritized over the past few decades as a response to the growing demands of the changing globalized world. Short-term education abroad has emerged as a common strategy that institutions implement to help internationalize their campuses, students, and faculty. Faculty are…

Impact of Short-Term Study Abroad Experiences on Transformative Learning

ERIC Educational Resources Information Center

Walters, Colleen; Charles, Jennell; Bingham, Sue

2017-01-01

In recent years, there has been a rapid rise in the number of universities offering students opportunities to study abroad. Traditional semester-long programs have been shortened with many new programs ranging anywhere from 1 to 8 weeks in length. The increased number of short-term programs has enabled professional degree programs, such as…

Short-Term Study Abroad: Perspectives on Speaking Gains and Language Contact

ERIC Educational Resources Information Center

Hernández, Todd A.

2016-01-01

Previous studies have shown that study abroad has a positive effect on second language (L2) learning outcomes for students who spend at least a semester abroad. It is unclear, however, whether a short-term experience also has a measurable impact on L2 development. The present study examines the relationship between speaking proficiency gains made…

Impaired Verbal Short-Term Memory in down Syndrome Reflects a Capacity Limitation Rather than Atypically Rapid Forgetting

ERIC Educational Resources Information Center

M. Purser, H.R.; Jarrold, C.

2005-01-01

Individuals with Down syndrome suffer from relatively poor verbal short-term memory. Recent work has indicated that this deficit is not caused by problems of audition, speech, or articulatory rehearsal within the phonological loop component of Baddeley and Hitch's working memory model. Given this, two experiments were conducted to investigate…

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.

Short-Term Visual Deprivation, Tactile Acuity, and Haptic Solid Shape Discrimination

PubMed Central

Crabtree, Charles E.; Norman, J. Farley

2014-01-01

Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task – perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task – the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation. PMID:25397327

Reproducibility of up-flow column percolation tests for contaminated soils

PubMed Central

Naka, Angelica; Sakanakura, Hirofumi; Kurosawa, Akihiko; Inui, Toru; Takeo, Miyuki; Inoba, Seiji; Watanabe, Yasutaka; Fujikawa, Takuro; Miura, Toshihiko; Miyaguchi, Shinji; Nakajou, Kunihide; Sumikura, Mitsuhiro; Ito, Kenichi; Tamoto, Shuichi; Tatsuhara, Takeshi; Chida, Tomoyuki; Hirata, Kei; Ohori, Ken; Someya, Masayuki; Katoh, Masahiko; Umino, Madoka; Negishi, Masanori; Ito, Keijiro; Kojima, Junichi; Ogawa, Shohei

2017-01-01

Up-flow column percolation tests are used at laboratory scale to assess the leaching behavior of hazardous substance from contaminated soils in a specific condition as a function of time. Monitoring the quality of these test results inter or within laboratory is crucial, especially if used for Environment-related legal policy or for routine testing purposes. We tested three different sandy loam type soils (Soils I, II and III) to determine the reproducibility (variability inter laboratory) of test results and to evaluate the difference in the test results within laboratory. Up-flow column percolation tests were performed following the procedure described in the ISO/TS 21268–3. This procedure consists of percolating solution (calcium chloride 1 mM) from bottom to top at a flow rate of 12 mL/h through softly compacted soil contained in a column of 5 cm diameter and 30 ± 5 cm height. Eluate samples were collected at liquid-to-solid ratio of 0.1, 0.2, 0.5, 1, 2, 5 and 10 L/kg and analyzed for quantification of the target elements (Cu, As, Se, Cl, Ca, F, Mg, DOC and B in this research). For Soil I, 17 institutions in Japan joined this validation test. The up-flow column experiments were conducted in duplicate, after 48 h of equilibration time and at a flow rate of 12 mL/h. Column percolation test results from Soils II and III were used to evaluate the difference in test results from the experiments conducted in duplicate in a single laboratory, after 16 h of equilibration time and at a flow rate of 36 mL/h. Overall results showed good reproducibility (expressed in terms of the coefficient of variation, CV, calculated by dividing the standard deviation by the mean), as the CV was lower than 30% in more than 90% of the test results associated with Soil I. Moreover, low variability (expressed in terms of difference between the two test results divided by the mean) was observed in the test results related to Soils II and III, with a variability lower than 30% in more than 88% of the cases for Soil II and in more than 96% of the cases for Soil III. We also discussed the possible factors that affect the reproducibility and variability in the test results from the up-flow column percolation tests. The low variability inter and within laboratory obtained in this research indicates that the ISO/TS 21268–3 can be successfully upgraded to a fully validated ISO standard. PMID:28582458

Improved Thermal Modulator for Gas Chromatography

NASA Technical Reports Server (NTRS)

Hasselbrink, Ernest Frederick, Jr.; Hunt, Patrick J.; Sacks, Richard D.

2008-01-01

An improved thermal modulator has been invented for use in a variant of gas chromatography (GC). The variant in question denoted as two-dimensional gas chromatography (2DGC) or GC-GC involves the use of three series-connected chromatographic columns, in the form of capillary tubes coated interiorly with suitable stationary phases (compounds for which different analytes exhibit different degrees of affinity). The two end columns are relatively long and are used as standard GC columns. The thermal modulator includes the middle column, which is relatively short and is not used as a standard GC column: instead, its temperature is modulated to affect timed adsorption and desorption of analyte gases between the two end columns in accordance with a 2DGC protocol.

A comparison of the short- and long-term effects of corticosterone exposure on extinction in adolescence versus adulthood.

PubMed

Den, Miriam Liora; Altmann, Sarah R; Richardson, Rick

2014-12-01

Human and nonhuman adolescents have impaired retention of extinction of learned fear, relative to juveniles and adults. It is unknown whether exposure to stress affects extinction differently in adolescents versus adults. These experiments compared the short- and long-term effects of exposure to the stress-related hormone corticosterone (CORT) on the extinction of learned fear in adolescent and adult rats. Across all experiments, adolescent and adult rats were trained to exhibit good extinction retention by giving extinction training across 2 consecutive days. Despite this extra training, adolescents exposed to 1 week of CORT (200 μg/ml) in their drinking water showed impaired extinction retention when trained shortly after the CORT was removed (Experiment 1a). In contrast, adult rats exposed to CORT (200 μg/ml) for the same duration did not exhibit deficits in extinction retention (Experiment 1b). Exposing adolescents to half the amount of CORT (100 μg/ml; Experiment 1c) for 1 week similarly disrupted extinction retention. Extinction impairments in adult rats were only observed after 3 weeks, rather than 1 week, of CORT (200 μg/ml; Experiment 1d). Remarkably, however, adult rats showed impaired extinction retention if they had been exposed to 1 week of CORT (200 μg/ml) during adolescence (Experiment 2). Finally, exposure to 3 weeks of CORT (200 μg/ml) in adulthood led to long-lasting extinction deficits after a 6-week drug-free period (Experiment 3). These findings suggest that although CORT disrupts both short- and long-term extinction retention in adolescents and adults, adolescents may be more vulnerable to these effects because of the maturation of stress-sensitive brain regions. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Time-Fractional Advection-Dispersion Equation (tFADE) to Quantify Aqueous Phase Contaminant Elution from a Trichloroethene (TCE) NAPL Source Zone in Sand Columns

NASA Astrophysics Data System (ADS)

Tick, G. R.; Wei, S.; Sun, H.; Zhang, Y.

2016-12-01

Pore-scale heterogeneity, NAPL distribution, and sorption/desorption processes can significantly affect aqueous phase elution and mass flux in porous media systems. The application of a scale-independent fractional derivative model (tFADE) was used to simulate elution curves for a series of columns (5 cm, 7 cm, 15 cm, 25 cm, and 80 cm) homogeneously packed with 20/30-mesh sand and distributed with uniform saturations (7-24%) of NAPL phase trichloroethene (TCE). An additional set of columns (7 cm and 25 cm) were packed with a heterogeneous distribution of quartz sand upon which TCE was emplaced by imbibing the immiscible liquid, under stable displacement conditions, to simulate a spill-type process. The tFADE model was able to better represent experimental elution behavior for systems that exhibited extensive long-term concentration tailing requiring much less parameters compared to typical multi-rate mass transfer models (MRMT). However, the tFADE model was not able to effectively simulate the entire elution curve for such systems with short concentration tailing periods since it assumes a power-law distribution for the dissolution rate for TCE. Such limitations may be solved using the tempered fractional derivative model, which can capture the single-rate mass transfer process and therefore the short elution concentration tailing behavior. Numerical solution for the tempered fractional-derivative model in bounded domains however remains a challenge and therefore requires further study. However, the tFADE model shows excellent promise for understanding impacts on concentration elution behavior for systems in which physical heterogeneity, non-uniform NAPL distribution, and pronounced sorption-desorption effects dominate or are present.

Searching for the Hebb effect in Down syndrome: evidence for a dissociation between verbal short-term memory and domain-general learning of serial order.

PubMed

Mosse, E K; Jarrold, C

2010-04-01

The Hebb effect is a form of repetition-driven long-term learning that is thought to provide an analogue for the processes involved in new word learning. Other evidence suggests that verbal short-term memory also constrains now vocabulary acquisition, but if the Hebb effect is independent of short-term memory, then it may be possible to demonstrate its preservation in a sample of individuals with Down syndrome, who typically show a verbal short-term memory deficit alongside surprising relative strengths in vocabulary. In two experiments, individuals both with and without Down syndrome (matched for receptive vocabulary) completed immediate serial recall tasks incorporating a Hebb repetition paradigm in either verbal or visuospatial conditions. Both groups demonstrated equivalent benefit from Hebb repetition, despite individuals with Down syndrome showing significantly lower verbal short-term memory spans. The resultant Hebb effect was equivalent across verbal and visuospatial domains. These studies suggest that the Hebb effect is essentially preserved within Down syndrome, implying that explicit verbal short-term memory is dissociable from potentially more implicit Hebb learning. The relative strength in receptive vocabulary observed in Down syndrome may therefore be supported by largely intact long-term as opposed to short-term serial order learning. This in turn may have implications for teaching methods and interventions that present new phonological material to individuals with Down syndrome.

The storage and recall of auditory memory.

PubMed

Nebenzahl, I; Albeck, Y

1990-01-01

The architecture of the auditory memory is investigated. The auditory information is assumed to be represented by f-t patterns. With the help of a psycho-physical experiment it is demonstrated that the storage of these patterns is highly folded in the sense that a long signal is broken into many short stretches before being stored in the memory. Recognition takes place by correlating newly heard input in the short term memory to information previously stored in the long term memory. We show that this correlation is performed after the input is accumulated and held statically in the short term memory.

Do lab-derived distribution coefficient values of pesticides match distribution coefficient values determined from column and field-scale experiments? A critical analysis of relevant literature.

PubMed

Vereecken, H; Vanderborght, J; Kasteel, R; Spiteller, M; Schäffer, A; Close, M

2011-01-01

In this study, we analyzed sorption parameters for pesticides that were derived from batch and column or batch and field experiments. The batch experiments analyzed in this study were run with the same pesticide and soil as in the column and field experiments. We analyzed the relationship between the pore water velocity of the column and field experiments, solute residence times, and sorption parameters, such as the organic carbon normalized distribution coefficient ( ) and the mass exchange coefficient in kinetic models, as well as the predictability of sorption parameters from basic soil properties. The batch/column analysis included 38 studies with a total of 139 observations. The batch/field analysis included five studies, resulting in a dataset of 24 observations. For the batch/column data, power law relationships between pore water velocity, residence time, and sorption constants were derived. The unexplained variability in these equations was reduced, taking into account the saturation status and the packing status (disturbed-undisturbed) of the soil sample. A new regression equation was derived that allows estimating the values derived from column experiments using organic matter and bulk density with an value of 0.56. Regression analysis of the batch/column data showed that the relationship between batch- and column-derived values depends on the saturation status and packing of the soil column. Analysis of the batch/field data showed that as the batch-derived value becomes larger, field-derived values tend to be lower than the corresponding batch-derived values, and vice versa. The present dataset also showed that the variability in the ratio of batch- to column-derived value increases with increasing pore water velocity, with a maximum value approaching 3.5. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Bacteriophage PRD1 batch experiments to study attachment, detachment and inactivation processes.

PubMed

Sadeghi, Gholamreza; Schijven, Jack F; Behrends, Thilo; Hassanizadeh, S Majid; van Genuchten, Martinus Th

2013-09-01

Knowledge of virus removal in subsurface environments is pivotal for assessing the risk of viral contamination of water resources and developing appropriate protection measures. Columns packed with sand are frequently used to quantify attachment, detachment and inactivation rates of viruses. Since column transport experiments are very laborious, a common alternative is to perform batch experiments where usually one or two measurements are done assuming equilibrium is reached. It is also possible to perform kinetic batch experiments. In that case, however, it is necessary to monitor changes in the concentration with time. This means that kinetic batch experiments will be almost as laborious as column experiments. Moreover, attachment and detachment rate coefficients derived from batch experiments may differ from those determined using column experiments. The aim of this study was to determine the utility of kinetic batch experiments and investigate the effects of different designs of the batch experiments on estimated attachment, detachment and inactivation rate coefficients. The experiments involved various combinations of container size, sand-water ratio, and mixing method (i.e., rolling or tumbling by pivoting the tubes around their horizontal or vertical axes, respectively). Batch experiments were conducted with clean quartz sand, water at pH 7 and ionic strength of 20 mM, and using the bacteriophage PRD1 as a model virus. Values of attachment, detachment and inactivation rate coefficients were found by fitting an analytical solution of the kinetic model equations to the data. Attachment rate coefficients were found to be systematically higher under tumbling than under rolling conditions because of better mixing and more efficient contact of phages with the surfaces of the sand grains. In both mixing methods, more sand in the container yielded higher attachment rate coefficients. A linear increase in the detachment rate coefficient was observed with increased solid-water ratio using tumbling method. Given the differences in the attachment rate coefficients, and assuming the same sticking efficiencies since chemical conditions of the batch and column experiments were the same, our results show that collision efficiencies of batch experiments are not the same as those of column experiments. Upscaling of the attachment rate from batch to column experiments hence requires proper understanding of the mixing conditions. Because batch experiments, in which the kinetics are monitored, are as laborious as column experiments, there seems to be no major advantage in performing batch instead of column experiments. Copyright © 2013 Elsevier B.V. All rights reserved.

Short- and long-term conditioning of a temperate marine diatom community to acidification and warming.

PubMed

Tatters, Avery O; Roleda, Michael Y; Schnetzer, Astrid; Fu, Feixue; Hurd, Catriona L; Boyd, Philip W; Caron, David A; Lie, Alle A Y; Hoffmann, Linn J; Hutchins, David A

2013-01-01

Ocean acidification and greenhouse warming will interactively influence competitive success of key phytoplankton groups such as diatoms, but how long-term responses to global change will affect community structure is unknown. We incubated a mixed natural diatom community from coastal New Zealand waters in a short-term (two-week) incubation experiment using a factorial matrix of warming and/or elevated pCO2 and measured effects on community structure. We then isolated the dominant diatoms in clonal cultures and conditioned them for 1 year under the same temperature and pCO2 conditions from which they were isolated, in order to allow for extended selection or acclimation by these abiotic environmental change factors in the absence of interspecific interactions. These conditioned isolates were then recombined into 'artificial' communities modelled after the original natural assemblage and allowed to compete under conditions identical to those in the short-term natural community experiment. In general, the resulting structure of both the unconditioned natural community and conditioned 'artificial' community experiments was similar, despite differences such as the loss of two species in the latter. pCO2 and temperature had both individual and interactive effects on community structure, but temperature was more influential, as warming significantly reduced species richness. In this case, our short-term manipulative experiment with a mixed natural assemblage spanning weeks served as a reasonable proxy to predict the effects of global change forcing on diatom community structure after the component species were conditioned in isolation over an extended timescale. Future studies will be required to assess whether or not this is also the case for other types of algal communities from other marine regimes.

AIRS Data Service at NASA Goddard Earth Sciences Data and Information Services (GES DISC) and Its Application to Climate Change Study

NASA Technical Reports Server (NTRS)

Won, Young-In; Vollimer, Bruce; Theobald, Mike; Hua, Xin-Min

2008-01-01

The Atmospheric Infrared Sounder (AIRS) instrument suite is designed to observe and characterize the entire atmospheric column from the surface to the top of the atmosphere in terms of surface emissivity and temperature, atmospheric temperature and humidity profiles, cloud amount and height, and the spectral outgoing infrared radiation on a global scale. The AIRS Data Support Team at the GES DISC provides data support to assist others in understanding, retrieving and extracting information from the AIRS/AMSU/HSB data products. Because a number of years has passed since its operation started, the amount of data has reached a certain level of maturity where we can address the climate change study utilizing AIRS data, In this presentation we will list various service we provide and to demonstrate how to utilize/apply the existing service to long-term and short-term variability study.

Attending to unrelated targets boosts short-term memory for color arrays.

PubMed

Makovski, Tal; Swallow, Khena M; Jiang, Yuhong V

2011-05-01

Detecting a target typically impairs performance in a second, unrelated task. It has been recently reported however, that detecting a target in a stream of distractors can enhance long-term memory of faces and scenes that were presented concurrently with the target (the attentional boost effect). In this study we ask whether target detection also enhances performance in a visual short-term memory task, where capacity limits are severe. Participants performed two tasks at once: a one shot, color change detection task and a letter-detection task. In Experiment 1, a central letter appeared at the same time as 3 or 5 color patches (memory display). Participants encoded the colors and pressed the spacebar if the letter was a T (target). After a short retention interval, a probe display of color patches appeared. Performance on the change detection task was enhanced when a target, rather than a distractor, appeared with the memory display. This effect was not modulated by memory load or the frequency of trials in which a target appeared. However, there was no enhancement when the target appeared at the same time as the probe display (Experiment 2a) or during the memory retention interval (Experiment 2b). Together these results suggest that detecting a target facilitates the encoding of unrelated information into visual short-term memory. Copyright © 2010 Elsevier Ltd. All rights reserved.

Fractional Skin Harvesting: Autologous Skin Grafting without Donor-site Morbidity

PubMed Central

Wang, Ying; Farinelli, William A.; Jiménez-Lozano, Joel; Franco, Walfre; Sakamoto, Fernanda H.; Cheung, Evelyn J.; Purschke, Martin; Doukas, Apostolos G.; Anderson, R. Rox

2013-01-01

Background: Conventional autologous skin grafts are associated with significant donor-site morbidity. This study was conducted to determine feasibility, safety, and efficacy of a new strategy for skin grafting based on harvesting small columns of full-thickness skin with minimal donor-site morbidity. Methods: The swine model was used for this study. Hundreds of full-thickness columns of skin tissue (~700 µm diameter) were harvested using a custom-made harvesting device, and then applied directly to excisional skin wounds. Healing in donor and graft sites was evaluated over 3 months by digital photographic measurement of wound size and blinded, computer-aided evaluation of histological features and compared with control wounds that healed by secondary intention or with conventional split-thickness skin grafts (STSG). Results: After harvesting hundreds of skin columns, the donor sites healed rapidly without scarring. These sites reepithelialized within days and were grossly and histologically indistinguishable from normal skin within 7 weeks. By contrast, STSG donor sites required 2 weeks for reepithelialization and retained scar-like characteristics in epidermal and dermal architecture throughout the experiment. Wounds grafted with skin columns resulted in accelerated reepithelialization compared with ungrafted wounds while avoiding the “fish-net” patterning caused by STSG. Conclusion: Full-thickness columns of skin can be harvested in large quantities with negligible long-term donor-site morbidity, and these columns can be applied directly to skin wounds to enhance wound healing. PMID:25289241

Soil microbial C:N ratio is a robust indicator of soil productivity for paddy fields

NASA Astrophysics Data System (ADS)

Li, Yong; Wu, Jinshui; Shen, Jianlin; Liu, Shoulong; Wang, Cong; Chen, Dan; Huang, Tieping; Zhang, Jiabao

2016-10-01

Maintaining good soil productivity in rice paddies is important for global food security. Numerous methods have been developed to evaluate paddy soil productivity (PSP), most based on soil physiochemical properties and relatively few on biological indices. Here, we used a long-term dataset from experiments on paddy fields at eight county sites and a short-term dataset from a single field experiment in southern China, and aimed at quantifying relationships between PSP and the ratios of carbon (C) to nutrients (N and P) in soil microbial biomass (SMB). In the long-term dataset, SMB variables generally showed stronger correlations with the relative PSP (rPSP) compared to soil chemical properties. Both correlation and variation partitioning analyses suggested that SMB N, P and C:N ratio were good predictors of rPSP. In the short-term dataset, we found a significant, negative correlation of annual rice yield with SMB C:N (r = -0.99), confirming SMB C:N as a robust indicator for PSP. In treatments of the short-term experiment, soil amendment with biochar lowered SMB C:N and improved PSP, while incorporation of rice straw increased SMB C:N and reduced PSP. We conclude that SMB C:N ratio does not only indicate PSP but also helps to identify management practices that improve PSP.

The effect of zinc supplementation of lactating rats on short-term and long-term memory of their male offspring.

PubMed

Karami, Mohammad; Ehsanivostacolaee, Simin; Moazedi, Ali Ahmad; Nosrati, Anahita

2013-01-01

In this study the effect of zinc chloride (ZnCl2) administration on the short-term and long-term memory of rats were assessed. We enrolled six groups of adult female and control group of eight Wistar rats in each group. One group was control group with free access to food and water, and five groups drunk zinc chloride in different doses (20, 30, 50, 70 and 100 mg/kg/day) in drinking water for two weeks during lactation .One month after birth, a shuttle box used to short- term and long-term memory and the latency in entering the dark chamber as well. This experiment showed that maternal 70 mg/kg dietary zinc during lactation influenced the working memory of rats' offspring in all groups. Rats received 100 mg/kg/day zinc during lactation so they had significant impairment in working memory (short-term) of their offspring (P<0.05). There was no significant difference in reference (long-term) memory of all groups. Drug consumption below70 mg/kg/day zinc chloride during lactation had no effect. While enhanced 100 mg/ kg/ day zinc in lactating rats could cause short-term memory impairment.

Towards the Complete Characterization of Marine-Terminating Glacier Outlet Systems

NASA Astrophysics Data System (ADS)

Mayer, L. A.; Jakobsson, M.; Mix, A. C.; Jerram, K.; Hogan, K.; Heffron, E.; Muenchow, A.

2016-12-01

The Petermann Glacier Experiment was aimed at understanding past variations in Petermann Glacier and their relationship to changes in climatic and oceanographic conditions. A critical component of the experiment was a comprehensive program conducted on the icebreaker Oden to map submarine glacial landforms, offering insight into past ice dynamics and establishing the overall geomorphological context of the region. Concurrent water-column mapping provided remarkable insight into modern glacial, oceanographic, and biological processes suggesting that a carefully designed experiment could provide a near-complete characterization of marine-terminating glacier outlet systems. Water-column mapping revealed seeps emanating from several seafloor regions. These features appeared along common depth zones and may represent fresh water emanating from a submerged aquifer; initial pore water analyses of cores also imply a fresh water flux into the fjord system. Water-column data also show a spatially consistent but variable distribution of a strong mid-water scattering layer, a biological response possibly tracing the inflow of Atlantic water into the fjord and enhanced by input from local outlet glaciers. The continuous nature of these acoustic records over 30 days offers a complete 4-D picture of the distribution of the scattering layer (and perhaps internal circulation patterns and water-mass interactions) with a spatial and temporal distribution far beyond that achievable by traditional oceanographic stations. Additional, higher-resolution water-column imaging around local outlet glaciers presents a clear picture of subglacial sediment-laden meltwater plumes. Thus in addition to the paleoceanographic information they provided, the acoustic systems deployed captured a 4D-view of many of the modern geological, oceanographic and ecological processes within and adjacent to the Petermann Glacier marine system. With the addition of seafloor and water-column sampling, long-term oceanographic moorings, a much more robust biological program (to understand what we are mapping in the water-column) and, the ability to extend our measurements under the ice sheet, we stand poised to truly characterize and hopefully understand the processes at work in front of marine-terminating outlet glaciers.

Using RSSCTs to predict field-scale GAC control of DBP formation

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

Cummings, L.; Summers, R.S.

1994-06-01

The primary objective of this study was to evaluate the use of the rapid small-scale column test (RSSCT) for predicting the control of disinfection by-product (DBP) formation by granular activated carbon (GAC). DBP formation was assessed by using a simulated distribution system (SDS) test and measuring trihalomethanes and total organic halide in the influent and effluent of the laboratory- and field-scale columns. It was observed that for the water studied, the RSSCTs effectively predicted the nonabsorbable fraction, time to 50 percent breakthrough, and the shape of the breakthrough curve for DBP formation. The advantage of RSSCTs is that conclusions aboutmore » the amenability of a GAC for DBP control can be reached in a short time period instead of at the end of a long-term pilot study. The authors recommend that similar studies be conducted with a range of source waters because the effectiveness of GAC is site-specific.« less

Perspectives on African Ozone from Sondes, Dobson and Aircraft Measurements

NASA Technical Reports Server (NTRS)

Thompson, A. M.; Witte, J. C.; Chatfield, R. B.; Diab, R. D.; Thouret, V.; Sauvage, B.

2004-01-01

We have been studying variability in ozone over Africa using data from ozonesondes (vertical profiles from surface to stratosphere), aircraft (the MOZAIC dataset with cruise altitude and landing/takeoff profiles) and the ground (Dobson spectrophotometer total ozone column measurement). The following may give context for ozone investigations during AMMA: 1. Total ozone measurements since 1989 show considerable variability in mean value among the African stations in Algeria, Kenya, Egypt, South Africa, as well as in seasonal cycles and year-to-year. Trends are not evident. 2. The impacts of convection, stratospheric injection, biomass burning and lightning appear in ozone sounding profile data. Time-series analysis and case studies point to periodic influences of long-range interactions with the Atlantic ("ozone paradox," wave-one") and Indian Oceans. 3. Tropospheric ozone variations, observed in tropospheric profiles and integrated column amount, follow general seasonal patterns but short- term variability is so strong that simple averages are inadequate for describing "climatology" and statistical classification approaches may be required.

Alfalfa Responses to Gypsum Application Measured Using Undisturbed Soil Columns

PubMed Central

Tirado-Corbalá, Rebecca; Slater, Brian K.; Dick, Warren A.; Barker, Dave

2017-01-01

Gypsum is an excellent source of Ca and S, both of which are required for crop growth. Large amounts of by-product gypsum [Flue gas desulfurization gypsum-(FGDG)] are produced from coal combustion in the United States, but only 4% is used for agricultural purposes. The objective of this study was to evaluate the effects of (1) untreated, (2) short-term (4-year annual applications of gypsum totaling 6720 kg ha−1), and (3) long-term (12-year annual applications of gypsum totaling 20,200 kg ha−1) on alfalfa (Medicago sativa L.) growth and nutrient uptake, and gypsum movement through soil. The study was conducted in a greenhouse using undisturbed soil columns of two non-sodic soils (Celina silt loam and Brookston loam). Aboveground growth of alfalfa was not affected by gypsum treatments when compared with untreated (p > 0.05). Total root biomass (0–75 cm) for both soils series was significantly increased by gypsum application (p = 0.04), however, increased root growth was restricted to 0–10 cm depth. Soil and plant analyses indicated no unfavorable environmental impact from of the 4-year and 12-year annual application of FGDG. We concluded that under sufficient water supply, by-product gypsum is a viable source of Ca and S for land application that might benefit alfalfa root growth, but has less effect on aboveground alfalfa biomass production. Undisturbed soil columns were a useful adaptation of the lysimeter method that allowed detailed measurements of alfalfa nutrient uptake, root biomass, and yield and nutrient movement in soil. PMID:28696383

Fabrication and investigation of electrochromatographic columns with a simplex configuration.

PubMed

Liu, Qing; Yang, Lijun; Wang, Qiuquan; Zhang, Bo

2014-07-04

Duplex capillary columns with a packed and an open section are widely used in electrochromatography (CEC). The duplex column configuration leads to non-uniform voltage drop, electrical field distribution and separation performance. It also adds to the complexity in understanding and optimizing electrochromatographic process. In this study, we introduced a simplex column configuration based on single particle fritting technology. The new column configuration has an essentially uniform packed bed through the entire column length, with only 1mm length left unpacked serving as the optical detection window. The study shows that a simplex column has higher separation efficiency than a duplex column, especially at the high voltage range, due to the consistent distribution of electrical field over the column length. In comparison to the duplex column, the simplex column presented a lower flow rate at the same applied voltage, suggesting that an open section may support a higher speed than a packed section. In practice, the long and short ends of the simplex column could be used as independent CEC columns respectively. This "two-in-one" bi-functional column configuration provided extra flexibilities in selecting and optimizing electrochromatographic conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

Complex resistivity signatures of ethanol biodegradation in porous media

USGS Publications Warehouse

Personna, Yves Robert; Slater, Lee; Ntarlagiannis, Dimitrios; Werkema, Dale D.; Szabo, Zoltan

2013-01-01

Numerous adverse effects are associated with the accidental release of ethanol (EtOH) and its persistence in the subsurface. Geophysical techniques may permit non-invasive, real time monitoring of microbial degradation of hydrocarbon. We performed complex resistivity (CR) measurements in conjunction with geochemical data analysis on three microbial-stimulated and two control columns to investigate changes in electrical properties during EtOH biodegradation processes in porous media. A Debye Decomposition approach was applied to determine the chargeability (m), normalized chargeability (mn) and time constant (τ) of the polarization magnitude and relaxation length scale as a function of time. The CR responses showed a clear distinction between the bioaugmented and control columns in terms of real (σ′) and imaginary (σ″) conductivity, phase (ϕ) and apparent formation factor (Fapp). Unlike the control columns, a substantial decrease in σ′ and increase in Fapp occurred at an early time (within 4 days) of the experiment for all three bioaugmented columns. The observed decrease in σ′ is opposite to previous studies on hydrocarbon biodegradation. These columns also exhibited increases in ϕ (up to ~ 9 mrad) and σ″ (up to two order of magnitude higher) 5 weeks after microbial inoculation. Variations in m and mn were consistent with temporal changes in ϕ and σ″ responses, respectively. Temporal geochemical changes and high resolution scanning electron microscopy imaging corroborated the CR findings, thus indicating the sensitivity of CR measurements to EtOH biodegradation processes. Our results offer insight into the potential application of CR measurements for long-term monitoring of biogeochemical and mineralogical changes during intrinsic and induced EtOH biodegradation in the subsurface.

Effects of irrelevant sounds on phonological coding in reading comprehension and short-term memory.

PubMed

Boyle, R; Coltheart, V

1996-05-01

The effects of irrelevant sounds on reading comprehension and short-term memory were studied in two experiments. In Experiment 1, adults judged the acceptability of written sentences during irrelevant speech, accompanied and unaccompanied singing, instrumental music, and in silence. Sentences varied in syntactic complexity: Simple sentences contained a right-branching relative clause (The applause pleased the woman that gave the speech) and syntactically complex sentences included a centre-embedded relative clause (The hay that the farmer stored fed the hungry animals). Unacceptable sentences either sounded acceptable (The dog chased the cat that eight up all his food) or did not (The man praised the child that sight up his spinach). Decision accuracy was impaired by syntactic complexity but not by irrelevant sounds. Phonological coding was indicated by increased errors on unacceptable sentences that sounded correct. These errors rates were unaffected by irrelevant sounds. Experiment 2 examined effects of irrelevant sounds on ordered recall of phonologically similar and dissimilar word lists. Phonological similarity impaired recall. Irrelevant speech reduced recall but did not interact with phonological similarity. The results of these experiments question assumptions about the relationship between speech input and phonological coding in reading and the short-term store.

What factors underlie children's susceptibility to semantic and phonological false memories? investigating the roles of language skills and auditory short-term memory.

PubMed

McGeown, Sarah P; Gray, Eleanor A; Robinson, Jamey L; Dewhurst, Stephen A

2014-06-01

Two experiments investigated the cognitive skills that underlie children's susceptibility to semantic and phonological false memories in the Deese/Roediger-McDermott procedure (Deese, 1959; Roediger & McDermott, 1995). In Experiment 1, performance on the Verbal Similarities subtest of the British Ability Scales (BAS) II (Elliott, Smith, & McCulloch, 1997) predicted correct and false recall of semantic lures. In Experiment 2, performance on the Yopp-Singer Test of Phonemic Segmentation (Yopp, 1988) did not predict correct recall, but inversely predicted the false recall of phonological lures. Auditory short-term memory was a negative predictor of false recall in Experiment 1, but not in Experiment 2. The findings are discussed in terms of the formation of gist and verbatim traces as proposed by fuzzy trace theory (Reyna & Brainerd, 1998) and the increasing automaticity of associations as proposed by associative activation theory (Howe, Wimmer, Gagnon, & Plumpton, 2009). Copyright © 2014 Elsevier B.V. All rights reserved.

Technical assessment of PSSC-supported experiments and demonstrations

NASA Technical Reports Server (NTRS)

1978-01-01

A description of CTS and ATS short-term and long-term satellite demonstration supported through usage of a satellite communication ground station complex is presented. User assessments about the programmatic impact of their demonstrations and experiments were summarized. The technical planning and coordination process involved in satellite utilization is also presented.

Short-Term Variability on the Scotian Shelf

NASA Astrophysics Data System (ADS)

Greenan, B.; Petrie, B.; Harrison, G.; Oakey, N.; Strain, P.

2002-12-01

The traditional view of the production cycle on the continental shelf of Nova Scotia features a spring bloom followed by a period of low production and a less intense fall bloom. The annual cycle of primary productivity thus has a large, low frequency component. However, there is increasing evidence that the production cycle has significant variability on shorter time scales. Physical, chemical and biological variability on the Scotian Shelf is examined on a daily to weekly timescale. This is accomplished through the use of a newly developed mooring platform (SeaHorse) that uses surface wave energy to enable the instrument to climb down the mooring wire and then float upwards while sampling the water column. This provides bi-hourly profiles of temperature, salinity, pressure and chlorophyll at one location over month-long periods. Results from the three-week deployment in October 2000 indicate a subsurface chlorophyll maximum below the pycnocline during the first part of the time series. An event occurred in mid-October during which the temperature, salinity and density iso-surfaces rose approximately 25 m. During this event, a small bloom, with peak chlorophyll concentrations of about 2 mg m-3 and duration of several days, began as nutrients were brought into the upper part of the water column by upwelling-favorable winds. SeaWiFS ocean color satellite images were valuable in providing a spatial context for chlorophyll concentrations, however, the lack of temporal resolution due to poor quality images means that this data set provided limited information for short-term chlorophyll variability. Gradient Richardson Numbers were estimated for 2 m vertical bins using SeaHorse CTD data and nearby ADCP current measurements. A trend of decreasing Ri in the ocean mixed layer with increasing surface wind stress is suggested.

Two dimensional model study of atmospheric transport using carbon-14 and strontium-90 as inert tracers

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

Kinnison, D.E.; Wuebbles, D.J.; Johnston, H.S.

1992-02-01

This study tests the transport processes in the LLNL two-dimensional chemical-radiative-transport model using recently reanalyzed carbon-14 and strontium-90 data. These radioactive tracers were produced bythe atmospheric nuclear bomb tests of 1952--58 and 1961--62, and they were measured at a few latitudes up to 35 kilometers over the period 1955--1970. Selected horizontal and vertical eddy diffusion coefficients were varied in the model to test their sensitivity to short and long term transpose of carbon-14. A sharp transition of K[sub zz] and K[sub yy] through the tropopause, as opposed to a slow transition between the same limiting values, shows a distinct improvementmore » in the calculated carbon-14 distributions, a distinct improvement in the calculated seasonal and latitudinal distribution of ozone columns (relative to TOMS observations), and a very large difference in the calculated ozone reduction by a possible fleet of High Speed Civil Transports. Calculated northern hemisphere carbon-14 is more sensitive to variation of K[sub yy] than are global ozone columns. Strontium-90 was used to test the LLNL tropopause height at four different latitudes. Starting with the 1960 background distribution of carbon-14, we calculate the input of carbon-14 as the sum of each nuclear test of the 1961--62 series, using two bomb-cloud rise models. With the Seitz bomb-rise formulation in the LLNL model, we find good agreement between calculated and observedcarbon-14 (with noticeable exceptions at the north polar tropopause and the short-term mid-latitude mid-stratosphere) between 1963 and 1970.« less

Two dimensional model study of atmospheric transport using carbon-14 and strontium-90 as inert tracers

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

Kinnison, D.E.; Wuebbles, D.J.; Johnston, H.S.

1992-02-01

This study tests the transport processes in the LLNL two-dimensional chemical-radiative-transport model using recently reanalyzed carbon-14 and strontium-90 data. These radioactive tracers were produced bythe atmospheric nuclear bomb tests of 1952--58 and 1961--62, and they were measured at a few latitudes up to 35 kilometers over the period 1955--1970. Selected horizontal and vertical eddy diffusion coefficients were varied in the model to test their sensitivity to short and long term transpose of carbon-14. A sharp transition of K{sub zz} and K{sub yy} through the tropopause, as opposed to a slow transition between the same limiting values, shows a distinct improvementmore » in the calculated carbon-14 distributions, a distinct improvement in the calculated seasonal and latitudinal distribution of ozone columns (relative to TOMS observations), and a very large difference in the calculated ozone reduction by a possible fleet of High Speed Civil Transports. Calculated northern hemisphere carbon-14 is more sensitive to variation of K{sub yy} than are global ozone columns. Strontium-90 was used to test the LLNL tropopause height at four different latitudes. Starting with the 1960 background distribution of carbon-14, we calculate the input of carbon-14 as the sum of each nuclear test of the 1961--62 series, using two bomb-cloud rise models. With the Seitz bomb-rise formulation in the LLNL model, we find good agreement between calculated and observedcarbon-14 (with noticeable exceptions at the north polar tropopause and the short-term mid-latitude mid-stratosphere) between 1963 and 1970.« less

Calcium- and Phosphorus-Supplemented Diet Increases Bone Mass after Short-Term Exercise and Increases Bone Mass and Structural Strength after Long-Term Exercise in Adult Mice

PubMed Central

Friedman, Michael A.; Bailey, Alyssa M.; Rondon, Matthew J.; McNerny, Erin M.; Sahar, Nadder D.; Kohn, David H.

2016-01-01

Exercise has long-lasting benefits to bone health that may help prevent fractures by increasing bone mass, bone strength, and tissue quality. Long-term exercise of 6–12 weeks in rodents increases bone mass and bone strength. However, in growing mice, a short-term exercise program of 3 weeks can limit increases in bone mass and structural strength, compared to non-exercised controls. Short-term exercise can, however, increase tissue strength, suggesting that exercise may create competition for minerals that favors initially improving tissue-level properties over structural-level properties. It was therefore hypothesized that adding calcium and phosphorus supplements to the diet may prevent decreases in bone mass and structural strength during a short-term exercise program, while leading to greater bone mass and structural strength than exercise alone after a long-term exercise program. A short-term exercise experiment was done for 3 weeks, and a long-term exercise experiment was done for 8 weeks. For each experiment, male 16-week old C57BL/6 mice were assigned to 4 weight-matched groups–exercise and non-exercise groups fed a control or mineral-supplemented diet. Exercise consisted of treadmill running at 12 m/min, 30 min/day for 7 days/week. After 3 weeks, exercised mice fed the supplemented diet had significantly increased tibial tissue mineral content (TMC) and cross-sectional area over exercised mice fed the control diet. After 8 weeks, tibial TMC, cross-sectional area, yield force, and ultimate force were greater from the combined treatments than from either exercise or supplemented diet alone. Serum markers of bone formation (PINP) and resorption (CTX) were both decreased by exercise on day 2. In exercised mice, day 2 PINP was significantly positively correlated with day 2 serum Ca, a correlation that was weaker and negative in non-exercised mice. Increasing dietary mineral consumption during an exercise program increases bone mass after 3 weeks and increases structural strength after 8 weeks, making bones best able to resist fracture. PMID:27008546

Non-Fickian dispersive transport of strontium in laboratory-scale columns: Modelling and evaluation

NASA Astrophysics Data System (ADS)

Liu, Dongxu; Jivkov, Andrey P.; Wang, Lichun; Si, Gaohua; Yu, Jing

2017-06-01

In the context of environmental remediation of contaminated sites and safety assessment of nuclear waste disposal in the near-surface zone, we investigate the leaching and non-Fickian dispersive migration with sorption of strontium (mocking strontium-90) through columns packed with sand and clay. Analysis is based on breakthrough curves (BTCs) from column experiments, which simulated rainfall infiltration and source term release scenario, rather than applying constant tracer solution at the inlet as commonly used. BTCs are re-evaluated and transport parameters are estimated by inverse modelling using two approaches: (1) equilibrium advection-dispersion equation (ADE); and (2) continuous time random walk (CTRW). Firstly, based on a method for calculating leach concentration, the inlet condition with an exponential decay input is identified. Secondly, the results show that approximately 39%-58% of Br- and 16%-49% of Sr2+ are eluted from the columns at the end of the breakthrough experiments. This suggests that trapping mechanisms, including diffusion into immobile zones and attachment of tracer on mineral surfaces, are more pronounced for Sr2+ than for Br-. Thirdly, we demonstrate robustness of CTRW-based truncated power-law (TPL) model in capturing non-Fickian reactive transport with 0 < β < 2, and Fickian transport with β > 2. The non-Fickian dispersion observed experimentally is explained by variations of local flow field from preferential flow paths due to physical heterogeneities. Particularly, the additional sorption process of strontium on clay minerals contributes to the delay of the peak concentration and the tailing features, which leads to an enhanced non-Fickian transport for strontium. Finally, the ADE and CTRW approaches to environmental modelling are evaluated. It is shown that CTRW with a sorption term can describe non-Fickian dispersive transport of strontium at laboratory scale by identifying appropriate parameters, while the traditional ADE with a retardation factor fails to reproduce the complex non-Fickian transport of strontium with strong sorption on clay surface.

The Professional Development of Teacher Identities in Hong Kong: Can a Short-Term Course Make a Difference?

ERIC Educational Resources Information Center

Trent, John

2011-01-01

This article reports on a qualitative study that explored the experiences of eight Hong Kong teachers of academic subjects who undertook a full-time, short-term professional development course (PDC) designed to provide them with specialized knowledge and classroom skills required to teach content subjects through the English medium. Using a…

Using an Intention/Reflection Practice to Focus Students towards Future Professions in a Short-Term International Travel Experience

ERIC Educational Resources Information Center

Fierke, Kerry K.; Lepp, Gardner A.; Bastianelli, Karen; Vogelsang, Lisa; Tornabene, Ladona

2016-01-01

The article describes a student-centered approach to generating meaningful learning outcomes in a short-term study abroad program. A practice named Intention/Reflection (I/R) was used to help students to identify, articulate, and reflect upon learning objectives that were personally meaningful, within the broader framework of the intended outcomes…

Orienting Attention within Visual Short-Term Memory: Development and Mechanisms

ERIC Educational Resources Information Center

Shimi, Andria; Nobre, Anna C.; Astle, Duncan; Scerif, Gaia

2014-01-01

How does developing attentional control operate within visual short-term memory (VSTM)? Seven-year-olds, 11-year-olds, and adults (total n = 205) were asked to report whether probe items were part of preceding visual arrays. In Experiment 1, central or peripheral cues oriented attention to the location of to-be-probed items either prior to…

Articulatory Suppression Effects on Short-Term Memory of Signed Digits and Lexical Items in Hearing Bimodal-Bilingual Adults

ERIC Educational Resources Information Center

Liu, Hsiu Tan; Squires, Bonita; Liu, Chun Jung

2016-01-01

We can gain a better understanding of short-term memory processes by studying different language codes and modalities. Three experiments were conducted to investigate: (a) Taiwanese Sign Language (TSL) digit spans in Chinese/TSL hearing bilinguals (n = 32); (b) American Sign Language (ASL) digit spans in English/ASL hearing bilinguals (n = 15);…

How Do Pre-Service Teachers Understand Intercultural Competence during a Short-Term Student Teaching Abroad Program: An Exploratory, Collective Case Study

ERIC Educational Resources Information Center

Barrow, Elizabeth Cynthia

2017-01-01

This dissertation explores how four pre-service teachers (PSTs) came to define and understand intercultural competence (ICC) during a short-term student teaching abroad program. In this exploratory, collective case study I highlight the participants' voice by analyzing their definitions of ICC before, during, and after their experience in Germany…

Attentional Demands Predict Short-Term Memory Load Response in Posterior Parietal Cortex

ERIC Educational Resources Information Center

Magen, Hagit; Emmanouil, Tatiana-Aloi; McMains, Stephanie A.; Kastner, Sabine; Treisman, Anne

2009-01-01

Limits to the capacity of visual short-term memory (VSTM) indicate a maximum storage of only 3 or 4 items. Recently, it has been suggested that activity in a specific part of the brain, the posterior parietal cortex (PPC), is correlated with behavioral estimates of VSTM capacity and might reflect a capacity-limited store. In three experiments that…

Does Content Matter? Analyzing the Change in Global Awareness between Business- and Nonbusiness-Focused Short-Term Study Abroad Courses

ERIC Educational Resources Information Center

DeLoach, Stephen B.; Kurt, Mark; Olitsky, Neal H.

2015-01-01

Business schools have long sought to increase students' global awareness. Short-term study abroad (STSA) experiences are becoming increasingly popular ways of generating awareness. While a handful of studies have found evidence of efficacy, none have specifically tested how courses with business content differ from other STSAs. Using a…

Short-Term Longitudinal Relationships between Children's Peer Victimization/Bullying Experiences and Self-Perceptions: Evidence for Reciprocity

ERIC Educational Resources Information Center

Boulton, Michael J.; Smith, Peter K.; Cowie, Helen

2010-01-01

This study tested transactional models to explain the short-term longitudinal links between self-perceptions and involvement in bullying and victimization among 115 9- to 10-year-old children. Self-perceptions were measured with Harter's Self-Perception Profile for Children (six sub-scales) and bullying/victimization by means of peer nominations.…

Short-Term Memory for Time in Children and Adults: A Behavioral Study and a Model

ERIC Educational Resources Information Center

Droit-Volet, Sylvie; Wearden, John; Delgado-Yonger, Maria

2007-01-01

This experiment investigated the effect of the short-term retention of duration on temporal discrimination in 5- and 8-year-olds, as well as in adults, by using an episodic temporal generalization task. In each age group, the participants' task was to compare two successive durations (a standard and a comparison duration) separated by a retention…

Resolving semantic and proactive interference in memory over the short-term.

PubMed

Atkins, Alexandra S; Berman, Marc G; Reuter-Lorenz, Patricia A; Lewis, Richard L; Jonides, John

2011-07-01

Interference is a major source of short-term errors of memory. The present investigation explores the relationship between two important forms of interference: proactive interference (PI), induced by the need to reject recently studied items no longer relevant to task performance, and semantic interference (SI), induced by the need to reject lures sharing a meaningful relationship with current memoranda. We explore the possibility that shared cognitive control processes are recruited to resolve both forms of interference. In Experiment 1, we find that the requirement to engage in articulatory suppression during the retention interval of tasks that induce either PI or SI increases both forms of interference similarly and selectively. In Experiment 2, we develop a task to examine PI and SI within the same experimental context. The results show interactive effects between factors that lead to the two forms of interference. Taken together, these findings support contextual-cuing models of short-term remembering (Nairne, Annual Review of Psychology, 53, 53-81 2002), where the context in which retrieval occurs can influence susceptibility to interference. Lastly, we discuss several theoretical hypotheses concerning the cognitive control processes that are recruited to resolve SI and PI in short-term remembering.

Resolving semantic and proactive interference in memory over the short-term

PubMed Central

Reuter-Lorenz, Patricia A.; Lewis, Richard L.; Jonides, John

2011-01-01

Interference is a major source of short-term errors of memory. The present investigation explores the relationship between two important forms of interference: proactive interference (PI), induced by the need to reject recently studied items no longer relevant to task performance, and semantic interference (SI), induced by the need to reject lures sharing a meaningful relationship with current memoranda. We explore the possibility that shared cognitive control processes are recruited to resolve both forms of interference. In Experiment 1, we find that the requirement to engage in articulatory suppression during the retention interval of tasks that induce either PI or SI increases both forms of interference similarly and selectively. In Experiment 2, we develop a task to examine PI and SI within the same experimental context. The results show interactive effects between factors that lead to the two forms of interference. Taken together, these findings support contextual-cuing models of short-term remembering (Nairne, Annual Review of Psychology, 53, 53–81 2002), where the context in which retrieval occurs can influence susceptibility to interference. Lastly, we discuss several theoretical hypotheses concerning the cognitive control processes that are recruited to resolve SI and PI in short-term remembering. PMID:21327614

A novel bench-scale column assay to investigate site-specific nitrification biokinetics in biological rapid sand filters.

PubMed

Tatari, K; Smets, B F; Albrechtsen, H-J

2013-10-15

A bench-scale assay was developed to obtain site-specific nitrification biokinetic information from biological rapid sand filters employed in groundwater treatment. The experimental set-up uses granular material subsampled from a full-scale filter, packed in a column, and operated with controlled and continuous hydraulic and ammonium loading. Flowrates and flow recirculation around the column are chosen to mimic full-scale hydrodynamic conditions, and minimize axial gradients. A reference ammonium loading rate is calculated based on the average loading experienced in the active zone of the full-scale filter. Effluent concentrations of ammonium are analyzed when the bench-scale column is subject to reference loading, from which removal rates are calculated. Subsequently, removal rates above the reference loading are measured by imposing short-term loading variations. A critical loading rate corresponding to the maximum removal rate can be inferred. The assay was successfully applied to characterize biokinetic behavior from a test rapid sand filter; removal rates at reference loading matched those observed from full-scale observations, while a maximum removal capacity of 6.9 g NH4(+)-N/m(3) packed sand/h could easily be determined at 7.5 g NH4(+)-N/m(3) packed sand/h. This assay, with conditions reflecting full-scale observations, and where the biological activity is subject to minimal physical disturbance, provides a simple and fast, yet powerful tool to gain insight in nitrification kinetics in rapid sand filters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Response of SO2 and Particulate Air Pollution to Local and Regional Emission Controls: A Case Study in Maryland

NASA Technical Reports Server (NTRS)

He, Hao; Vinnikov, Konstantin Y.; Li, Can; Krotkov, Nickolay Anatoly; Jongeward, Andrew R.; Li, Zhanqing; Stehr, Jeffrey W.; Hains, Jennifer; Dickerson, RUssell R.

2016-01-01

This paper addresses the questions of what effect local regulations can have on pollutants with different lifetimes and how surface observations and remotely sensed data can be used to determine the impacts. We investigated the decadal trends of tropospheric sulfur dioxide (SO2) and aerosol pollution over Maryland and its surrounding states, using surface, aircraft, and satellite measurements. Aircraft measurements indicated fewer isolated SO2 plumes observed in summers, a 40 decrease of column SO2, and a 20 decrease of atmospheric optical depth (AOD) over Maryland after the implementation of local regulations on sulfur emissions from power plants (90 reduction from 2010). Surface observations of SO2 and particulate matter (PM) concentrations in Maryland show similar trends. OMI SO2 and MODIS AOD observations were used to investigate the column contents of air pollutants over the eastern U.S.; these indicate decreasing trends in column SO2 (60 decrease) and AOD (20 decrease). The decrease of upwind SO2 emissions also reduced aerosol loadings over the downwind Atlantic Ocean near the coast by 20, while indiscernible changes of the SO2 column were observed. A step change of SO2 emissions in Maryland starting in 20092010 had an immediate and profound benefit in terms of local surface SO2 concentrations but a modest impact on aerosol pollution, indicating that short-lived pollutants are effectively controlled locally, while long-lived pollutants require regional measures.

Crossing the Cartesian Divide: An Investigation into the Role of Emotion in Science Learning

NASA Astrophysics Data System (ADS)

Staus, Nancy L.

Although many science educators and researchers believe that emotion is an important part of the learning process, few researchers have dealt with the topic in a systematic fashion. The purpose of this study was to examine the role of emotion in the learning process, particularly in the learning of science content. My study utilized a dimensional perspective which defined emotion in terms of arousal and valence, and drew on research from the fields of psychology and neuroscience to examine how emotion affects different aspects of cognition such as attention and memory. On the basis of these findings, I developed and tested a path model to investigate the predicted relationships among emotional arousal, valence, attention, intrinsic motivation and short- and long-term learning outcomes. I conducted the study in two phases. The first phase took place in a psychology laboratory in which participants watched either an exciting or neutral nature video, read a factual article related to the video and were tested on their learning. The second phase took place at the Oregon Coast Aquarium in which participants watched a narrated otter or sea lion presentation and took a short posttest after the show. In both phases, participants' emotional arousal, valence, attention, and motivation levels were also measured for inclusion in the model. The results indicated that emotional arousal was an important predictor of short-term learning in both experiments although its effect was fully mediated by attention at the aquarium. In addition, negative valence (displeasure) and intrinsic motivation were strong predictors of short-term learning in the laboratory experiment. At the aquarium, the narrator of the animal presentation strongly affected both attention and short-term learning---visitors who listened to a non-scripted rather than a scripted narration paid more attention and had significantly better short-term learning outcomes. In the aquarium study, emotional arousal correlated strongly with several measures of long-term learning. In particular, those who felt more arousal during the animal presentation were able to describe their experience at greater length and with more detail and complexity two to three months after their visit. My findings suggest that emotional arousal is an important component of science learning both directly and through its relationship with attention. Therefore, science educators in both informal and formal learning institutions may be able to increase both attention and learning outcomes by designing emotionally arousing learning experiences around the science content they wish to teach. In addition, the importance of narrator quality in the aquarium study suggests that narrators and teachers should be trained to deliver information in such a way that supports short- and long-term science learning.

Long-term manure application increased greenhouse gas emissions but had no effect on ammonia volatilization in a Northern China upland field.

PubMed

Zhang, Tao; Liu, Hongbin; Luo, Jiafa; Wang, Hongyuan; Zhai, Limei; Geng, Yucong; Zhang, Yitao; Li, Jungai; Lei, Qiuliang; Bashir, Muhammad Amjad; Wu, Shuxia; Lindsey, Stuart

2018-08-15

The impacts of manure application on soil ammonia (NH 3 ) volatilization and greenhouse gas (GHG) emissions are of interest for both agronomic and environmental reasons. However, how the swine manure addition affects greenhouse gas and N emissions in North China Plain wheat fields is still unknown. A long-term fertilization experiment was carried out on a maize-wheat rotation system in Northern China (Zea mays L-Triticum aestivum L.) from 1990 to 2017. The experiment included four treatments: (1) No fertilizer (CK), (2) single application of chemical fertilizers (NPK), (3) NPK plus 22.5t/ha swine manure (NPKM), (4) NPK plus 33.7t/ha swine manure (NPKM+). A short-term fertilization experiment was conducted from 2016 to 2017 using the same treatments in a field that had been abandoned for decades. The emissions of NH 3 and GHGs were measured during the wheat season from 2016 to 2017. Results showed that after long-term fertilization the wheat yields for NPKM treatment were 7105kg/ha, which were higher than NPK (3880kg/ha) and NPKM+ treatments (5518kg/ha). The wheat yields were similar after short-term fertilization (6098-6887kg/ha). The NH 3 -N emission factors (EF amm ) for NPKM and NPKM+ treatments (1.1 and 1.1-1.4%, respectively) were lower than NPK treatment (2.2%) in both the long and short-term fertilization treatments. In the long- and short-term experiments the nitrous oxide (N 2 O) emission factors (EF nit ) for NPKM+ treatment were 4.2% and 3.7%, respectively, which were higher than for the NPK treatment (3.5% and 2.5%, respectively) and the NPKM treatment (3.6% and 2.2%, respectively). In addition, under long and short-term fertilization, the greenhouse gas intensities for the NPKM+ treatment were 33.7 and 27.0kg CO 2 -eq/kg yield, respectively, which were higher than for the NPKM treatment (22.8 and 21.1kg CO 2 -eq/kg yield, respectively). These results imply that excessive swine manure application does not increase yield but increases GHG emissions. Copyright © 2018 Elsevier B.V. All rights reserved.

Hurricane Arthur and its effect on the short-term variability of pCO2 on the Scotian Shelf, NW Atlantic

NASA Astrophysics Data System (ADS)

Lemay, Jonathan; Thomas, Helmuth; Craig, Susanne E.; Burt, William J.; Fennel, Katja; Greenan, Blair J. W.

2018-04-01

The understanding of the seasonal variability of carbon cycling on the Scotian Shelf in the NW Atlantic Ocean has improved in recent years; however, very little information is available regarding its short-term variability. In order to shed light on this aspect of carbon cycling on the Scotian Shelf we investigate the effects of Hurricane Arthur, which passed the region on 5 July 2014. The hurricane caused a substantial decline in the surface water partial pressure of CO2 (pCO2), even though the Scotian Shelf possesses CO2-rich deep waters. High-temporal-resolution data of moored autonomous instruments demonstrate that there is a distinct layer of relatively cold water with low dissolved inorganic carbon (DIC) slightly above the thermocline, presumably due to a sustained population of phytoplankton. Strong storm-related wind mixing caused this cold intermediate layer with high phytoplankton biomass to be entrained into the surface mixed layer. At the surface, phytoplankton begin to grow more rapidly due to increased light. The combination of growth and the mixing of low DIC water led to a short-term reduction in the partial pressure of CO2 until wind speeds relaxed and allowed for the restratification of the upper water column. These hurricane-related processes caused a (net) CO2 uptake by the Scotian Shelf region that is comparable to the spring bloom, thus exerting a major impact on the annual CO2 flux budget.

Post-abortion adjustment of health care professionals in training.

PubMed

Lemkau, J P

1991-01-01

Sixty-three women students of the health care professions were surveyed about their abortion and post-abortion experiences, feelings, and attitudes. Variables predictive of short- and long-term adjustment, belief in the wisdom of the choice, and right to choose were analysed, as were effects on emotional and attitudinal responses of passage of time and pressure to abort. Most reported mild, transient, short-term negative effects, and generally benign long-term effects. Implications of the findings are discussed.

Temporal grouping effects in musical short-term memory.

PubMed

Gorin, Simon; Mengal, Pierre; Majerus, Steve

2018-07-01

Recent theoretical accounts of verbal and visuo-spatial short-term memory (STM) have proposed the existence of domain-general mechanisms for the maintenance of serial order information. These accounts are based on the observation of similar behavioural effects across several modalities, such as temporal grouping effects. Across two experiments, the present study aimed at extending these findings, by exploring a STM modality that has received little interest so far, STM for musical information. Given its inherent rhythmic, temporal and serial organisation, the musical domain is of interest for investigating serial order STM processes such as temporal grouping. In Experiment 1, the data did not allow to determine the presence or the absence of temporal grouping effects. In Experiment 2, we observed that temporal grouping of tone sequences during encoding improves short-term recognition for serially presented probe tones. Furthermore, the serial position curves included micro-primacy and micro-recency effects, which are the hallmark characteristic of temporal grouping. Our results suggest that the encoding of serial order information in musical STM may be supported by temporal positional coding mechanisms similar to those reported in the verbal domain.

Continuous bind-and-elute protein A capture chromatography: Optimization under process scale column constraints and comparison to batch operation.

PubMed

Kaltenbrunner, Oliver; Diaz, Luis; Hu, Xiaochun; Shearer, Michael

2016-07-08

Recently, continuous downstream processing has become a topic of discussion and analysis at conferences while no industrial applications of continuous downstream processing for biopharmaceutical manufacturing have been reported. There is significant potential to increase the productivity of a Protein A capture step by converting the operation to simulated moving bed (SMB) mode. In this mode, shorter columns are operated at higher process flow and corresponding short residence times. The ability to significantly shorten the product residence time during loading without appreciable capacity loss can dramatically increase productivity of the capture step and consequently reduce the amount of Protein A resin required in the process. Previous studies have not considered the physical limitations of how short columns can be packed and the flow rate limitations due to pressure drop of stacked columns. In this study, we are evaluating the process behavior of a continuous Protein A capture column cycling operation under the known pressure drop constraints of a compressible media. The results are compared to the same resin operated under traditional batch operating conditions. We analyze the optimum system design point for a range of feed concentrations, bed heights, and load residence times and determine achievable productivity for any feed concentration and any column bed height. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:938-948, 2016. © 2016 American Institute of Chemical Engineers.

Flow-through Column Experiments and Modeling of Microbially Mediated Cr(VI) Reduction at Hanford 100H

NASA Astrophysics Data System (ADS)

Yang, L.; Molins, S.; Beller, H. R.; Brodie, E. L.; Steefel, C.; Nico, P. S.; Han, R.

2010-12-01

Microbially mediated Cr(VI) reduction at the Hanford 100H area was investigated by flow-through column experiments. Three separate experiments were conducted to promote microbial activities associated with denitrification, iron and sulfate reduction, respectively. Replicate columns packed with natural sediments from the site under anaerobic environment were injected with 5mM Lactate as the electron donor and 5 μM Cr(VI) in all experiments. Sulfate and nitrate solutions were added to act as the main electron acceptors in the respective experiments, while iron columns relied on the indigenous sediment iron (and manganese) oxides as electron acceptors. Column effluent solutions were analyzed by IC and ICP-MS to monitor the microbial consumption/conversion of lactate and the associated Cr(VI) reduction. Biogeochemical reactive transport modeling was performed to gain further insights into the reaction mechanisms and Cr(VI) bioreduction rates. All experimental columns showed a reduction of the injected Cr(VI). Columns under denitrifying conditions showed the least Cr(VI) reduction at early stages (<60 days) compared to columns run under other experimental conditions, but became more active over time, and ultimately showed the most consistent Cr(VI) reduction. A strong correlation between denitrification and Cr(VI) reduction processes was observed and was in agreement with the results obtained in batch experiments with a denitrifying bacterium isolated from the Hanford site. The accumulation of nitrite does not appear to have an adverse effect on Cr(VI) reduction rates. Reactive transport simulations indicated that biomass growth completely depleted influent ammonium, and called for an additional source of N to account for the measured reduction rates. Iron columns were the least active with undetectable consumption of the injected lactate, slowest cell growth, and the smallest change in Cr(VI) concentrations during the course of the experiment. In contrast, columns under sulfate-reducing/fermentative conditions exhibited the greatest Cr(VI) reduction capacity. Two sulfate columns evolved to complete lactate fermentation with acetate and propionate produced in the column effluent after 40 days of experiments. These fermenting columns showed a complete removal of injected Cr(VI), visible precipitation of sulfide minerals, and a significant increase in effluent Fe and Mn concentrations. Reactive transport simulations suggested that direct reduction of Cr(VI) by Fe(II) and Mn(II) released from the sediment could account for the observed Cr(VI) removal. The biogeochemical modeling was employed to test two hypotheses that could explain the release of Fe(II) and Mn(II) from the column sediments: 1) acetate produced by lactate fermentation provided the substrate for the growth of iron(III) and manganese(IV) oxide reducers, and 2) direct reduction of iron(III) and manganese(IV) oxides by hydrogen sulfide generated during sulfate reduction. Overall, experimental and modeling results suggested that Cr(VI) reduction in the sulfate-reducing columns occurred through a complex network of microbial reactions that included fermentation, sulfate reduction, and possibly the stimulated iron-reducing communities.

The short- and long-term consequences of directed forgetting in a working memory task.

PubMed

Festini, Sara B; Reuter-Lorenz, Patricia A

2013-01-01

Directed forgetting requires the voluntary control of memory. Whereas many studies have examined directed forgetting in long-term memory (LTM), the mechanisms and effects of directed forgetting within working memory (WM) are less well understood. The current study tests how directed forgetting instructions delivered in a WM task influence veridical memory, as well as false memory, over the short and long term. In a modified item recognition task Experiment 1 tested WM only and demonstrated that directed forgetting reduces false recognition errors and semantic interference. Experiment 2 replicated these WM effects and used a surprise LTM recognition test to assess the long-term effects of directed forgetting in WM. Long-term veridical memory for to-be-remembered lists was better than memory for to-be-forgotten lists-the directed forgetting effect. Moreover, fewer false memories emerged for to-be-forgotten information than for to-be-remembered information in LTM as well. These results indicate that directed forgetting during WM reduces semantic processing of to-be-forgotten lists over the short and long term. Implications for theories of false memory and the mechanisms of directed forgetting within working memory are discussed.

Experimental investigation of cesium mobility in the course of secondary mineral formations in Hanford sediment columns at 50 degrees C.

PubMed

Mashal, Kholoud Y; Cetiner, Ziya S

2010-10-01

Formation of secondary minerals and Cs mobility in Hanford sediments were investigated under conditions similar to the Hanford tank leak in a dynamic flow system at 50 degrees C. The objectives were to (1) examine the nature and locations of secondary mineral phases precipitated in the sediments and (2) quantify the amount of Cs retained by the sediment matrix at 50 degrees C. To this end, Hanford sediments were packed into 10-cm long columns and leached with simulated tank waste consisting of 1.4 M NaOH, 0.125 M NaAlO(2), 3.7 M NaNO(3), and 1.3 x 10(-4) M Cs at 50 degrees C. Compositions of outflow solution were monitored with time for up to 25 days, and the columns were then segmented into four 2.5-cm long layers. The colloidal fraction in these segments was characterized in terms of mineralogy, particle morphology, Cs content, and short-range Al and Si structure. It was observed that cancrinite and sodalite precipitated at 50 degrees C. Approximately 53% Cs was retained in the column treated by the simulated tank waste at this temperature. Cesium retention in the column was lowered in the high ionic strength solution due to competition from Na for the exchange sites. This can be explained by alteration of distribution and number of sorption sites which reduces the selectivity of Cs for Na, and through the formation of cancrinite and sodalite. The formation of hydroxide complexes in highly alkaline solutions could also contribute to relatively poor retention of Cs by hindering ion exchange mechanism.

Towards a Better Understanding of the Oxygen Isotope Signature of Atmospheric CO2: Determining the 18O-Exchange Between CO2 and H2O in Leaves and Soil On-line with Laser-Based Spectroscopy

NASA Astrophysics Data System (ADS)

Gangi, L.; Rothfuss, Y.; Vereecken, H.; Brueggemann, N.

2013-12-01

The oxygen isotope signature of carbon dioxide (δ18O-CO2) is a powerful tool to disentangle CO2 fluxes in terrestrial ecosystems, as CO2 attains a contrasting 18O signature by the interaction with isotopically different soil and leaf water pools during soil respiration and photosynthesis, respectively. However, using the δ18O-CO2 signal to quantify plant-soil-atmosphere CO2 fluxes is still challenging due to a lack of knowledge concerning the magnitude and effect of individual fractionation processes during CO2 and H2O diffusion and during CO2-H2O isotopic exchange in soils and leaves, especially related to short-term changes in environmental conditions (non-steady state). This study addresses this research gap by combined on-line monitoring of the oxygen isotopic signature of CO2 and water vapor during gas exchange in soil and plant leaves with laser-based spectroscopy, using soil columns and plant chambers. In both experimental setups, the measured δ18O of water vapor was used to infer the δ18O of liquid water, and, together with the δ18O-CO2, the degree of oxygen isotopic equilibrium between the two species (θ). Gas exchange experiments with different functional plant types (C3 coniferous, C3 monocotyledonous, C3 dicotyledonous, C4) revealed that θ and the influence of the plant on the ambient δ18O-CO2 (CO18O-isoforcing) not only varied on a diurnal timescale but also when plants were exposed to limited water availability, elevated air temperature, and abrupt changes in light intensity (sunflecks). Maximum θ before treatments ranged between 0.7 and 0.8 for the C3 dicotyledonous (poplar) and C3 monocotyledonous (wheat) plants, and between 0.5 and 0.6 for the conifer (spruce) and C4 plant (maize) while maximum CO18O-isoforcing was highest in wheat (0.03 m s-1 ‰), similar in poplar and maize (0.02 m s-1 ‰), and lowest in spruce (0.01 m s-1 ‰). Multiple regression analysis showed that up to 97 % of temporal dynamics in CO18O-isoforcing could be explained by variations in stomatal conductance, θ, and δ18O of H2O at the evaporation site. The determined maximum in vivo activity of carbonic anhydrase, the enzyme which catalyzes the CO2-H2O oxygen isotope exchange inside leaves, varied between the different plant species and was, as observed for θ, higher in poplar and wheat, and lower in maize and spruce. Preliminary experiments with soil columns filled with sand demonstrated that gas-permeable microporous polypropylene tubing, which was installed at different depths in the soil columns, was appropriate for determining δ18O-H2O and δ18O-CO2 simultaneously without fractionation. Hence, this new methodology is promising for further studies on the oxygen isotopic exchange between CO2 and H2O in soils. Altogether, this study highlights that the δ18O-CO2 exchange in the soil-plant-atmosphere continuum is highly dynamic in response to short-term variations in environmental conditions, and emphasizes the need for an improved parameterization of models simulating δ18O-CO2.

Short-period circumnutations found in sunflower hypocotyls in satellite orbit. A reappraisal of data from Spacelab-1

NASA Technical Reports Server (NTRS)

Bardal, Tom Kr; Johnsson, Anders; Chapman, David K.; Sager, J. C. (Principal Investigator)

2003-01-01

We have further analysed data from an experiment performed in satellite orbit, in Spacelab-1. In micro-gravity the hypocotyls of Helianthus annuus, cv. "Teddy Bear", showed short period circumnutations (periods around 30 minutes) as well as the already reported long period nutations (with an average period of about 115 minutes). We applied various types of signal analysis (Fourier and wavelet analysis) to the data series. The long period circumnutations have a larger amplitude than the short term circumnutations. Both short and long period circumnutations exist in one and the same hypocotyl. (This is in contrast to our ground control experiments, where were found only the long-period nutations.) The period of the nutations changed throughout the experiment. These results are extending the conclusions drawn after the Spacelab experiment (Brown et al. 1990). In particular they emphasize the existence of both short- and long-period circumnutations in micro-gravity.

Retroactive interference in short-term memory and the word-length effect.

PubMed

Campoy, Guillermo

2011-09-01

Two experiments investigated the possibility that the word-length effect in short-term memory (STM) is a consequence of long words generating a greater level of retroactive interference than shorter words. In Experiment 1, six-word lists were auditorily presented under articulatory suppression for immediate serial reconstruction of only the first three words. These three words were always drawn from a single set of middle-length words, whereas the last three positions were occupied by either short or long interfering words. The results showed worse memory performance when the to-be-remembered words were followed by long words. In Experiment 2, a recent-probes task was used, in which recent negative probes matched a target word in trial n-2. The results showed lower levels of proactive interference when trial n-1 involved long words instead of short words, suggesting that long words displaced previous STM content to a greater extent. By two different experimental approaches, therefore, this study shows that long words produce more retroactive interference than short words, supporting an interference-based account for the word-length effect. Copyright © 2011 Elsevier B.V. All rights reserved.

Specific deficit of colour-colour short-term memory binding in sporadic and familial Alzheimer's disease.

PubMed

Parra, Mario A; Sala, Sergio Della; Abrahams, Sharon; Logie, Robert H; Méndez, Luis Guillermo; Lopera, Francisco

2011-06-01

Short-term memory binding of visual features which are processed across different dimensions (shape-colour) is impaired in sporadic Alzheimer's disease, familial Alzheimer's disease, and in asymptomatic carriers of familial Alzheimer's disease. This study investigated whether Alzheimer's disease also impacts on within-dimension binding processes. The study specifically explored whether visual short-term memory binding of features of the same type (colour-colour) is sensitive to Alzheimer's disease. We used a neuropsychological battery and a short-term memory binding task to assess patients with sporadic Alzheimer's disease (Experiment 1), familial Alzheimer's disease (Experiment 2) due to the mutation E280A of the Presenilin-1 gene and asymptomatic carriers of the mutation. The binding task assessed change detection within arrays of unicoloured objects (Colour Only) or bicoloured objects the colours of which had to be remembered separately (Unbound Colours) or together (Bound Colours). Performance on the Bound Colours condition (1) explained the largest proportion of variance between patients (sporadic and familial Alzheimer's disease), (2) combined more sensitivity and specificity for the disease than other more traditional neuropsychological tasks, (3) identified asymptomatic carriers of the mutation even when traditional neuropsychological measures and other measures of short-term memory did not and, (4) contrary to shape-colour binding, correlated with measures of hippocampal functions. Colour-colour binding and shape-colour binding both appear to be sensitive to AD even though they seem to rely on different brain mechanisms. Copyright © 2011 Elsevier Ltd. All rights reserved.

Long-term consolidation of declarative memory: insight from temporal lobe epilepsy.

PubMed

Tramoni, Eve; Felician, Olivier; Barbeau, Emmanuel J; Guedj, Eric; Guye, Maxime; Bartolomei, Fabrice; Ceccaldi, Mathieu

2011-03-01

Several experiments carried out with a subset of patients with temporal lobe epilepsy have demonstrated normal memory performance at standard delays of recall (i.e. minutes to hours) but impaired performance over longer delays (i.e. days or weeks), suggesting altered long-term consolidation mechanisms. These mechanisms were specifically investigated in a group of five adult-onset pharmaco-sensitive patients with temporal lobe epilepsy, exhibiting severe episodic memory complaints despite normal performance at standardized memory assessment. In a first experiment, the magnitude of autobiographical memory loss was evaluated using retrograde personal memory tasks based on verbal and visual cues. In both conditions, results showed an unusual U-shaped pattern of personal memory impairment, encompassing most of the patients' life, sparing however, periods of the childhood, early adulthood and past several weeks. This profile was suggestive of a long-term consolidation impairment of personal episodes, adequately consolidated over 'short-term' delays but gradually forgotten thereafter. Therefore, in a subsequent experiment, patients were submitted to a protocol specifically devised to investigate short and long-term consolidation of contextually-bound experiences (episodic memory) and context-free information (semantic knowledge and single-items). In the short term (1 h), performance at both contextually-free and contextually-bound memory tasks was intact. After a 6-week delay, however, contextually-bound memory performance was impaired while contextually-free memory performance remained preserved. This effect was independent of task difficulty and the modality of retrieval (recall and recognition). Neuroimaging studies revealed the presence of mild metabolic changes within medial temporal lobe structures. Taken together, these results show the existence of different consolidation systems within declarative memory. They suggest that mild medial temporal lobe dysfunction can impede the building and stabilization of episodic memories but leaves long-term semantic and single-items mnemonic traces intact.

Auditory short-term memory activation during score reading.

PubMed

Simoens, Veerle L; Tervaniemi, Mari

2013-01-01

Performing music on the basis of reading a score requires reading ahead of what is being played in order to anticipate the necessary actions to produce the notes. Score reading thus not only involves the decoding of a visual score and the comparison to the auditory feedback, but also short-term storage of the musical information due to the delay of the auditory feedback during reading ahead. This study investigates the mechanisms of encoding of musical information in short-term memory during such a complicated procedure. There were three parts in this study. First, professional musicians participated in an electroencephalographic (EEG) experiment to study the slow wave potentials during a time interval of short-term memory storage in a situation that requires cross-modal translation and short-term storage of visual material to be compared with delayed auditory material, as it is the case in music score reading. This delayed visual-to-auditory matching task was compared with delayed visual-visual and auditory-auditory matching tasks in terms of EEG topography and voltage amplitudes. Second, an additional behavioural experiment was performed to determine which type of distractor would be the most interfering with the score reading-like task. Third, the self-reported strategies of the participants were also analyzed. All three parts of this study point towards the same conclusion according to which during music score reading, the musician most likely first translates the visual score into an auditory cue, probably starting around 700 or 1300 ms, ready for storage and delayed comparison with the auditory feedback.

Auditory Short-Term Memory Activation during Score Reading

PubMed Central

Simoens, Veerle L.; Tervaniemi, Mari

2013-01-01

Performing music on the basis of reading a score requires reading ahead of what is being played in order to anticipate the necessary actions to produce the notes. Score reading thus not only involves the decoding of a visual score and the comparison to the auditory feedback, but also short-term storage of the musical information due to the delay of the auditory feedback during reading ahead. This study investigates the mechanisms of encoding of musical information in short-term memory during such a complicated procedure. There were three parts in this study. First, professional musicians participated in an electroencephalographic (EEG) experiment to study the slow wave potentials during a time interval of short-term memory storage in a situation that requires cross-modal translation and short-term storage of visual material to be compared with delayed auditory material, as it is the case in music score reading. This delayed visual-to-auditory matching task was compared with delayed visual-visual and auditory-auditory matching tasks in terms of EEG topography and voltage amplitudes. Second, an additional behavioural experiment was performed to determine which type of distractor would be the most interfering with the score reading-like task. Third, the self-reported strategies of the participants were also analyzed. All three parts of this study point towards the same conclusion according to which during music score reading, the musician most likely first translates the visual score into an auditory cue, probably starting around 700 or 1300 ms, ready for storage and delayed comparison with the auditory feedback. PMID:23326487

Mini-columns for Conducting Breakthrough Experiments. Design and Construction

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

Dittrich, Timothy M.; Reimus, Paul William; Ware, Stuart Douglas

Experiments with moderately and strongly sorbing radionuclides (i.e., U, Cs, Am) have shown that sorption between experimental solutions and traditional column materials must be accounted for to accurately determine stationary phase or porous media sorption properties (i.e., sorption site density, sorption site reaction rate coefficients, and partition coefficients or K d values). This report details the materials and construction of mini-columns for use in breakthrough columns to allow for accurate measurement and modeling of sorption parameters. Material selection, construction techniques, wet packing of columns, tubing connections, and lessons learned are addressed.

Thinking of serving nursing abroad: how technology assists nurses on mission trips.

PubMed

Brown, Rachel M

2015-06-01

Advances in technology have assisted in the proliferation of short-term, faith-based international medical mission trips. Many of these mission trips include health care not only to local citizens but also building schools and churches and sharing the Gospel of Jesus Christ. Included in this article are my own personal experiences in short-term, faith-based medical missions. A step-by-step guide is offered to help prepare inexperienced mission participants gain insight into short-term mission trips. Advanced planning, fundraising, collaboration, and being open to change are key elements to successful participation in these life-changing missions. Copyright © 2015 Elsevier Inc. All rights reserved.

Central Composite Design Optimization of Zinc Removal from Contaminated Soil, Using Citric Acid as Biodegradable Chelant.

PubMed

Asadzadeh, Farrokh; Maleki-Kaklar, Mahdi; Soiltanalinejad, Nooshin; Shabani, Farzin

2018-02-08

Citric acid (CA) was evaluated in terms of its efficiency as a biodegradable chelating agent, in removing zinc (Zn) from heavily contaminated soil, using a soil washing process. To determine preliminary ranges of variables in the washing process, single factor experiments were carried out with different CA concentrations, pH levels and washing times. Optimization of batch washing conditions followed using a response surface methodology (RSM) based central composite design (CCD) approach. CCD predicted values and experimental results showed strong agreement, with an R 2 value of 0.966. Maximum removal of 92.8% occurred with a CA concentration of 167.6 mM, pH of 4.43, and washing time of 30 min as optimal variable values. A leaching column experiment followed, to examine the efficiency of the optimum conditions established by the CCD model. A comparison of two soil washing techniques indicated that the removal efficiency rate of the column experiment (85.8%) closely matching that of the batch experiment (92.8%). The methodology supporting the research experimentation for optimizing Zn removal may be useful in the design of protocols for practical engineering soil decontamination applications.

The Role of Work Placement in Engineering Students' Academic Performance

ERIC Educational Resources Information Center

Blicblau, Aaron Simon; Nelson, Tracey Louise; Dini, Kurosh

2016-01-01

Engineering graduates without industrial experience may find that employment is difficult to obtain immediately after completing their studies. This study investigates the impact of two arrangements of work experiences; short term (over 12 weeks, STP) and long-term (over 52 weeks, IBL) on academic grades. This study involved 240 undergraduate…

Sequential Processes in Image Generation: An Objective Measure. Technical Report #6.

ERIC Educational Resources Information Center

Kosslyn, Stephen M.; And Others

This paper investigates the processes by which visual mental images--the precept-like short-term memory representations--are created from information stored in long-term memory. It also presents a new method for studying image generation. Three experiments were conducted using college students as subjects. In the first experiment, a Podgorny and…

Evidence for Decay in Verbal Short-Term Memory: A Commentary on Berman, Jonides, and Lewis (2009)

ERIC Educational Resources Information Center

Campoy, Guillermo

2012-01-01

M. G. Berman, J. Jonides, and R. L. Lewis (2009) adapted the recent-probes task to investigate the causes of forgetting in short-term memory. In 7 experiments, they studied the persistence of memory traces by assessing the level of proactive interference generated by previous-trial items over a range of intertrial intervals. None of the…

Effect of simple shear flow on photosynthesis rate and morphology of micro algae

NASA Astrophysics Data System (ADS)

Mitsuhashi, S.; Fujimoto, M.; Muramatsu, H.; Tanishita, K.

The convective motion of micro algal suspension gives an advantageous effect on the photosynthetic rate in the bioreactor, however, the nature of convective effect on the photosynthesis has not been fully understood. The propose of this study concerns the nature of photosynthetic rate in a well-defined hydrodynamic shear flow of Spirulina platensis suspension, generated in a double rotating coaxial cylinders. The double rotating coaxial cylinders was installed in the incubator chamber with the controlled illumination intensity and temperature. Two kind of experiments, short and long term experiments, were performed to evaluate the direct effect of shear flow on the photosynthetic rate. The short term experiment indicates that the simple shear flow enables to augment the photosynthesis of Spirulina suspension and simultaneously causes the cell destruction due to the excessive shear stress. The long term experiment for 100 hours reveals that the growth rate and the morphology of Spirulina is sensitive to the external fluid mechanical stimulus. The long term application of mechanical stress on the algae may result in the adaptation of the photosynthetic function and morphology.

Heavy metals in urban soils of East St. Louis, IL. Part II: Leaching characteristics and modeling.

PubMed

Kaminski, M D; Landsberger, S

2000-09-01

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produced organic and inorganic chemicals, and petroleum refineries. Following a gross assessment of heavy metals in the community soils (see Part I of this two-part series), leaching tests were performed on specific soils to elucidate heavy metal-associated mineral fractions and general leachability. Leaching experiments, including the Toxicity Characteristic Leaching Procedure (TLCP) and column tests, and sequential extractions, illustrated the low leachability of metals in East St. Louis soils. The column leachate results were modeled using a formulation developed for fly ash leaching. The importance of instantaneous dissolution was evident from the model. By incorporating desorption/adsorption terms into the source term, the model was adapted very well to the time-dependent heavy metal leachate concentrations. The results demonstrate the utility of a simple model to describe heavy metal leaching from contaminated soils.

Heavy Metals in Urban Soils of East St. Louis, IL Part II: Leaching Characteristics and Modeling.

PubMed

Kaminski, Michael D; Landsberger, Sheldon

2000-09-01

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produced organic and inorganic chemicals, and petroleum refineries. Following a gross assessment of heavy metals in the community soils (see Part I of this two-part series), leaching tests were performed on specific soils to elucidate heavy metal-associated mineral fractions and general leachability. Leaching experiments, including the Toxicity Characteristic Leaching Procedure (TLCP) and column tests, and sequential extractions, illustrated the low leachability of metals in East St. Louis soils. The column leachate results were modeled using a formulation developed for fly ash leaching. The importance of instantaneous dissolution was evident from the model. By incorporating desorption/adsorption terms into the source term, the model was adapted very well to the time-dependent heavy metal leachate concentrations. The results demonstrate the utility of a simple model to describe heavy metal leaching from contaminated soils.

Achieving quasi-adiabatic thermal environment to maximize resolution power in very high-pressure liquid chromatography: Theory, models, and experiments.

PubMed

Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A

2016-04-29

A cylindrical vacuum chamber (inner diameter 5 cm) housing a narrow-bore 2.1 mm×100 mm column packed with 1.8 μm HSS-T3 fully porous particles was built in order to isolate thermally the chromatographic column from the external air environment. Consistent with statistical physics and the mean free path of air molecules, the experimental results show that natural air convection and conduction are fully eliminated for housing air pressures smaller than 10(-4) Torr. Heat radiation is minimized by wrapping up the column with low-emissivity aluminum-tape (emissivity coefficient ϵ=0.03 vs. 0.28 for polished stainless steel 316). Overall, the heat flux at the column wall is reduced by 96% with respect to standard still-air ovens. From a practical viewpoint, the efficiency of the column run at a flow rate of 0.6 mL/min at a constant 13,000 psi pressure drop (the viscous heat power is around 9 W/m) is improved by up to 35% irrespective of the analyte retention. Models of heat and mass transfer reveal that (1) the amplitude of the radial temperature gradient is significantly reduced from 0.30 to 0.01 K and (2) the observed improvement in resolution power stems from a more uniform distribution of the flow velocity across the column diameter. The eddy dispersion term in the van Deemter equation is reduced by 0.8±0.1 reduced plate height unit, a significant gain in column performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a slicing device for Apollo-Soyuz Test Project (ASTP) electrophoresis technology experiment MA-011

NASA Technical Reports Server (NTRS)

Nerren, B. H.

1977-01-01

The electrophoresis of six columns was accomplished on the Apollo-Soyuz test Project. After separation, these columns were frozen in orbit and were returned for ground-based analyses. One major goal of the MA-011 experiment was the assessment of the separation achieved in orbit by slicing these frozen columns. The slicing of the frozen columns required a new device. The development of that device is described.

Comparison between Procedures using Sodium Dodecyl Sulfate for Shotgun Proteomic Analyses of Complex Samples

PubMed Central

Bereman, Michael S.; Egertson, Jarrett D.; MacCoss, Michael J.

2012-01-01

Filter aided sample preparation (FASP) and a new sample preparation method using a modified commercial SDS removal spin column are quantitatively compared in terms of their performance for shotgun proteomic experiments in three complex proteomic samples: a Saccharomyces cerevisiae lysate (insoluble fraction), a Caenorhabditis elegans lysate (soluble fraction), and a human embryonic kidney cell line (HEK293T). The characteristics and total number of peptides and proteins identified are compared between the two procedures. The SDS spin column procedure affords a conservative 4-fold improvement in throughput, is more reproducible, less expensive (i.e., requires less materials), and identifies between 30–107% more peptides at a q≤0.01, than the FASP procedure. The peptides identified by SDS spin column are more hydrophobic than species identified by the FASP procedure as indicated by the distribution of GRAVY scores. Ultimately, these improvements correlate to as great as a 50% increase in protein identifications with 2 or more peptides. PMID:21656683

Behavior of short silica monolithic columns in high pressure gas chromatography.

PubMed

Maniquet, Adrien; Bruyer, Nicolas; Raffin, Guy; Baco-Antoniali, Franck; Demesmay, Claire; Dugas, Vincent; Randon, Jérôme

2016-08-19

In order to analyze light hydrocarbons mixtures with silica monolithic columns, a conventional gas chromatograph was modified to work with carrier gas pressure as high as 60bar. To understand hydrodynamic flow and retention with short columns (less than 30cm), special attention was required due to the temperature difference between the oven area and the FID detector which contain a significant length of the column. Efficiency and selectivity using various carrier gases (helium, nitrogen and carbon dioxide) at different inlet pressure for different oven temperature were studied. Carrier gas nature was a very significant parameter: on one side, linked to adsorption mechanism for gases like nitrogen and carbon dioxide onto the stationary phase modifying retention and selectivity, on the other side in relation to the minimum theoretical plate height which was as low as 15μm (66 000 platem(-1)) using carbon dioxide as carrier gas. The chromatographic system was then used to separate methane, ethane, ethylene, acetylene, propane, cyclopropane, and butane in less than 30s. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of microbial processes on gas generation under expected WIPP repository conditions: Annual report through 1992

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

Francis, A.J.; Gillow, J.B.

1993-09-01

Microbial processes involved in gas generation from degradation of the organic constituents of transuranic waste under conditions expected at the Waste Isolation Pilot Plant (WIPP) repository are being investigated at Brookhaven National Laboratory. These laboratory studies are part of the Sandia National Laboratories -- WIPP Gas Generation Program. Gas generation due to microbial degradation of representative cellulosic waste was investigated in short-term (< 6 months) and long-term (> 6 months) experiments by incubating representative paper (filter paper, paper towels, and tissue) in WIPP brine under initially aerobic (air) and anaerobic (nitrogen) conditions. Samples from the WIPP surficial environment and undergroundmore » workings harbor gas-producing halophilic microorganisms, the activities of which were studied in short-term experiments. The microorganisms metabolized a variety of organic compounds including cellulose under aerobic, anaerobic, and denitrifying conditions. In long-term experiments, the effects of added nutrients (trace amounts of ammonium nitrate, phosphate, and yeast extract), no nutrients, and nutrients plus excess nitrate on gas production from cellulose degradation.« less

Patient-Reported Outcome and Observer-Reported Outcome Assessment in Rare Disease Clinical Trials: An ISPOR COA Emerging Good Practices Task Force Report.

PubMed

Benjamin, Katy; Vernon, Margaret K; Patrick, Donald L; Perfetto, Eleanor; Nestler-Parr, Sandra; Burke, Laurie

Rare diseases (RDs) affect a small number of people within a population. About 5000 to 8000 distinct RDs have been identified, with an estimated 6% to 8% of people worldwide suffering from an RD. Approximately 75% of RDs affect children. Frequently, these conditions are heterogeneous; many are progressive. Regulatory incentives have increased orphan drug designations and approvals. To develop emerging good practices for RD outcomes research addressing the challenges inherent in identifying, selecting, developing, adapting, and implementing patient-reported outcome (PRO) and observer-reported outcome (ObsRO) assessments for use in RD clinical trials. This report outlines the challenges and potential solutions in determining clinical outcomes for RD trials. It follows the US Food and Drug Administration Roadmap to Patient-Focused Outcome Measurement in Clinical Trials. The Roadmap consists of three columns: 1) Understanding the Disease or Condition, 2) Conceptualizing Treatment Benefit, and 3) Selecting/Developing the Outcome Measure. Challenges in column 1 include factors such as incomplete natural history data and heterogeneity of disease presentation and patient experience. Solutions include using several information sources, for example, clinical experts and patient advocacy groups, to construct the condition's natural history and understand treatment patterns. Challenges in column 2 include understanding and measuring treatment benefit from the patient's perspective, especially given challenges in defining the context of use such as variations in age or disease severity/progression. Solutions include focusing on common symptoms across patient subgroups, identifying short-term outcomes, and using multiple types of COA instruments to measure the same constructs. Challenges in column 3 center around the small patient population and heterogeneity of the condition or study sample. Few disease-specific instruments for RDs exist. Strategies include adapting existing instruments developed for a similar condition or that contain symptoms of importance to the RD patient population, or using a generic instrument validated for the context of use. This report provides state-of-the-art solutions to patient-reported outcome (PRO) and observer-reported outcome (ObsRO) assessments challenges in clinical trials of patients with RDs. These recommended solutions are both pragmatic and creative and posed with clear recognition of the global regulatory context used in RD clinical development programs. Copyright © 2017. Published by Elsevier Inc.

The effects of short-term and long-term learning on the responses of lateral intraparietal neurons to visually presented objects

PubMed Central

Sigurdardottir, Heida M.; Sheinberg, David L.

2015-01-01

The lateral intraparietal area (LIP) of the dorsal visual stream is thought to play an important role in visually directed orienting, or the guidance of where to look and pay attention. LIP can also respond selectively to differently shaped objects. We sought to understand how and to what extent short-term and long-term experience with visual orienting can determine the nature of responses of LIP neurons to objects of different shapes. We taught monkeys to arbitrarily associate centrally presented objects of various shapes with orienting either toward or away from a preferred peripheral spatial location of a neuron. For some objects the training lasted for less than a single day, while for other objects the training lasted for several months. We found that neural responses to visual objects are affected both by such short-term and long-term experience, but that the length of the learning period determines exactly how this neural plasticity manifests itself. Short-term learning over the course of a single training session affects neural responses to objects, but these effects are only seen relatively late after visual onset; at this time, the neural responses to newly learned objects start to resemble those of familiar over-learned objects that share their meaning or arbitrary association. Long-term learning, on the other hand, affects the earliest and apparently bottom-up responses to visual objects. These responses tend to be greater for objects that have repeatedly been associated with looking toward, rather than away from, LIP neurons’ preferred spatial locations. Responses to objects can nonetheless be distinct even though the objects have both been similarly acted on in the past and will lead to the same orienting behavior in the future. Our results therefore also indicate that a complete experience-driven override of LIP object responses is difficult or impossible. PMID:25633647

Retinoid hyposignaling contributes to aging-related decline in hippocampal function in short-term/working memory organization and long-term declarative memory encoding in mice.

PubMed

Mingaud, Frédérique; Mormede, Cécile; Etchamendy, Nicole; Mons, Nicole; Niedergang, Betty; Wietrzych, Marta; Pallet, Véronique; Jaffard, Robert; Krezel, Wojciech; Higueret, Paul; Marighetto, Aline

2008-01-02

An increasing body of evidence indicates that the vitamin A metabolite retinoic acid (RA) plays a role in adult brain plasticity by activating gene transcription through nuclear receptors. Our previous studies in mice have shown that a moderate downregulation of retinoid-mediated transcription contributed to aging-related deficits in hippocampal long-term potentiation and long-term declarative memory (LTDM). Here, knock-out, pharmacological, and nutritional approaches were used in a series of radial-arm maze experiments with mice to further assess the hypothesis that retinoid-mediated nuclear events are causally involved in preferential degradation of hippocampal function in aging. Molecular and behavioral findings confirmed our hypothesis. First, a lifelong vitamin A supplementation, like short-term RA administration, was shown to counteract the aging-related hippocampal (but not striatal) hypoexpression of a plasticity-related retinoid target-gene, GAP43 (reverse transcription-PCR analyses, experiment 1), as well as short-term/working memory (STWM) deterioration seen particularly in organization demanding trials (STWM task, experiment 2). Second, using a two-stage paradigm of LTDM, we demonstrated that the vitamin A supplementation normalized memory encoding-induced recruitment of (hippocampo-prefrontal) declarative memory circuits, without affecting (striatal) procedural memory system activity in aged mice (Fos neuroimaging, experiment 3A) and alleviated their LTDM impairment (experiment 3B). Finally, we showed that (knock-out, experiment 4) RA receptor beta and retinoid X receptor gamma, known to be involved in STWM (Wietrzych et al., 2005), are also required for LTDM. Hence, aging-related retinoid signaling hypoexpression disrupts hippocampal cellular properties critically required for STWM organization and LTDM formation, and nutritional vitamin A supplementation represents a preventive strategy. These findings are discussed within current neurobiological perspectives questioning the historical consensus on STWM and LTDM system partition.

Beryllium sensitization and disease among long-term and short-term workers in a beryllium ceramics plant.

PubMed

Henneberger, P K; Cumro, D; Deubner, D D; Kent, M S; McCawley, M; Kreiss, K

2001-04-01

Workers at a beryllium ceramics plant were tested for beryllium sensitization and disease in 1998 to determine whether the plant-wide prevalence of sensitization and disease had declined since the last screening in 1992; an elevated prevalence was associated with specific processes or with high exposures; exposure-response relationships differed for long-term workers hired before the last plant-wide screening and short-term workers hired since then. Current workers were asked to complete a questionnaire and to provide blood for the beryllium lymphocyte proliferation test (BeLPT). Those with an abnormal BeLPT were classified as sensitized, and were offered clinical evaluation for beryllium disease. Task- and time-specific measurements of airborne beryllium were combined with individual work histories to compute mean, cumulative, and peak beryllium exposures for each worker. The 151 participants represented 90% of 167 eligible workers. Fifteen (9.9% of 151) had an abnormal BeLPT and were split between long-term workers (8/77 = 10.4%) and short-term workers (7/74 = 9.5%). Beryllium disease was detected in 9.1% (7/77) of long-term workers but in only 1.4% (1/74) of short-term workers (P = 0.06), for an overall prevalence of 5.3% (8/151). These prevalences were similar to those observed in the earlier survey. The prevalence of sensitization was elevated in 1992 among machinists, and was still elevated in 1998 among long-term workers (7/40 = 18%) but not among short-term workers (2/36 = 6%) with machining experience. The prevalence of sensitization was also elevated in both groups of workers for the processes of lapping, forming, firing, and packaging. The data suggested a positive relationship between peak beryllium exposure and sensitization for long-term workers and between mean, cumulative, and peak exposure and sensitization for short-term workers, although these findings were not statistically significant. Long-term workers with either a high peak exposure or work experience in forming were more likely to have an abnormal BeLPT (8/51 = 16%) than the other long-term workers (0/26, P = 0.05). All seven sensitized short-term workers either had high mean beryllium exposure or had worked longest in forming or machining (7/55 = 13% versus 0/19, P = 0.18). A plant-wide decline in beryllium exposures between the 1992 and 1998 surveys was not matched by a decline in the prevalence of sensitization and disease. Similar to findings from other studies, beryllium sensitization/disease was associated with specific processes and elevated exposures. The contrast in disease prevalence between long-term and short-term workers suggests that beryllium sensitization can occur after a short period of exposure, but beryllium disease usually requires a longer latency and/or period of exposure. The findings from this study motivated interventions to more aggressively protect and test workers, and new research into skin exposure as a route of sensitization and the contribution of individual susceptibility.

The Short- and Long-Term Effects of a Short Study Abroad Experience: The Case of Children

ERIC Educational Resources Information Center

Llanes, Angels

2012-01-01

This study examines to what extent L2 gains obtained during a study abroad (SA) experience are durable. Participants were 16 Catalan/Spanish bilingual children, learning English as an L2, who were distributed into two groups depending on their learning context (SA vs. at home [AH]). Participants completed a pre-test before the SA participants'…

Reutilization of granite powder as an amendment and fertilizer for acid soils.

PubMed

Barral Silva, M T; Silva Hermo, B; García-Rodeja, E; Vázquez Freire, N

2005-11-01

The properties of granite powders--a granite manufacturing waste product-were analyzed to assess their potential use as amendments and fertilizers on acid soils. Two types of powders were characterized: one produced during cutting of granite with a diamond-edged disc saw, comprising only rock powder, the other produced during cutting with a multi-blade bandsaw, containing calcium hydroxide and metal filings added during the cutting procedure. The acid neutralizing capacity of the granite powders was assessed in short- (2-3 h) and medium-term (1-30 d) experiments. The powders showed a buffering capacity at around pH 8, which corresponded to the rapid dissolution of basic cations, and another buffering effect at pH<4.5, attributable to the dissolution of Fe and Al. The acid neutralizing capacity (ANC) determined in the short-term experiments, to a final pH of 4.5, varied between 5 and 61 cmol H+kg(-1) powder. The ANC to pH 4.5 obtained in the medium-term experiments was much higher than that obtained in the short-term experiments, reaching a maximum ANC value of 200 cmol H+kg(-1) powder. There was no great difference in the neutralizing capacity determined at between 1 and 30 d. The most abundant elements in acid solutions obtained at the end of medium-term experiments were Mg and Ca for disc saw powders, whereas Ca and Fe (at pH<5) were the most soluble elements in the bandsaw powders. The rapid release of these cations suggests the possible effective use of the granite powders as a source of nutrients on being added to acid soils.

Short-term scheduling of an open-pit mine with multiple objectives

NASA Astrophysics Data System (ADS)

Blom, Michelle; Pearce, Adrian R.; Stuckey, Peter J.

2017-05-01

This article presents a novel algorithm for the generation of multiple short-term production schedules for an open-pit mine, in which several objectives, of varying priority, characterize the quality of each solution. A short-term schedule selects regions of a mine site, known as 'blocks', to be extracted in each week of a planning horizon (typically spanning 13 weeks). Existing tools for constructing these schedules use greedy heuristics, with little optimization. To construct a single schedule in which infrastructure is sufficiently utilized, with production grades consistently close to a desired target, a planner must often run these heuristics many times, adjusting parameters after each iteration. A planner's intuition and experience can evaluate the relative quality and mineability of different schedules in a way that is difficult to automate. Of interest to a short-term planner is the generation of multiple schedules, extracting available ore and waste in varying sequences, which can then be manually compared. This article presents a tool in which multiple, diverse, short-term schedules are constructed, meeting a range of common objectives without the need for iterative parameter adjustment.

Gas-liquid two-phase flow behaviors and performance characteristics of proton exchange membrane fuel cells in a short-term microgravity environment

NASA Astrophysics Data System (ADS)

Guo, Hang; Liu, Xuan; Zhao, Jian Fu; Ye, Fang; Ma, Chong Fang

2017-06-01

In this work, proton exchange membrane fuel cells (PEMFCs) with transparent windows are designed to study the gas-liquid two-phase flow behaviors inside flow channels and the performance of a PEMFC with vertical channels and a PEMFC with horizontal channels in a normal gravity environment and a 3.6 s short-term microgravity environment. Experiments are conducted under high external circuit load and low external circuit load at low temperature where is 35 °C. The results of the present experimental work demonstrate that the performance and the gas-liquid two-phase flow behaviors of the PEMFC with vertical channels exhibits obvious changes when the PEMFCs enter the 3.6 s short-term microgravity environment from the normal gravity environment. Meanwhile, the performance of the PEMFC with vertical channels increases after the PEMFC enters the 3.6 s short-term microgravity environment under high external circuit load, while under low external circuit load, the PEMFC with horizontal channels exhibits better performance in both the normal gravity environment and the 3.6 s short-term microgravity environment.

Percutaneous Breast Biopsy: Effect on Short-term Quality of Life

PubMed Central

Humphrey, Kathryn L.; Donelan, Karen; Kong, Chung Y.; Williams, Olubunmi; Itauma, Omosalewa; Halpern, Elkan F.; Gerade, Beverly J.; Rafferty, Elizabeth A.; Swan, J. Shannon

2014-01-01

Purpose To examine the effects of percutaneous breast biopsy on short-term quality of life. Materials and Methods The institutional review board approved this HIPAA-compliant prospective study. From December 1, 2007, through February 28, 2010, women undergoing percutaneous breast biopsy in an academic medical center were recruited to participate in a mixed-mode survey 2–4 days after biopsy. Patients described their biopsy experience by using the Testing Morbidities Index (TMI), a validated instrument for assessing short-term quality of life related to diagnostic testing. The scale ranged from 0 (worst possible experience) to 100 (no adverse effects). Seven attributes were assessed: pain or discomfort before and during testing, fear or anxiety before and during testing, embarrassment during testing, and physical and mental function after testing. Demographic and clinical information were also collected. Univariate and multivariate linear regression analyses were performed to identify significant predictors of TMI score. Results In 188 women (mean age, 51.4 years; range, 22–80 years), the mean TMI score (±standard deviation) was 82 ± 12. Univariate analysis revealed age and race as significant predictors of the TMI score (P < .05). In the multivariate model, only patient age remained a significant independent predictor (P = .001). TMI scores decreased by approximately three points for every decade decrease in patient age, which suggests that younger women were more adversely affected by the biopsy experience. Conclusion Younger patient age is a significant predictor of decreased short-term quality of life related to percutaneous breast biopsy procedures. Tailored prebiopsy counseling may better prepare women for percutaneous biopsy procedures and improve their experience. © RSNA, 2013 PMID:24471385

Isolation of Three Components from Spearmint Oil: An Exercise in Column and Thin-Layer Chromatography

ERIC Educational Resources Information Center

Davies, Don R.; Johnson, Todd M.

2007-01-01

A simple experiment for undergraduate organic chemistry students to separate a colorless mixture using column chromatography and then monitor the outcome of the separation using thin-layer chromatography (TLC) and infrared spectroscopy(IR) is described. The experiment teaches students the principle and techniques of column and thin-layer…

Colloid-Facilitated Transport of 137Cs in Fracture-Fill Material. Experiments and Modeling

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

Dittrich, Timothy M.; Reimus, Paul William

2015-10-29

In this study, we demonstrate how a combination of batch sorption/desorption experiments and column transport experiments were used to effectively parameterize a model describing the colloid-facilitated transport of Cs in the Grimsel granodiorite/FFM system. Cs partition coefficient estimates onto both the colloids and the stationary media obtained from the batch experiments were used as initial estimates of partition coefficients in the column experiments, and then the column experiment results were used to obtain refined estimates of the number of different sorption sites and the adsorption and desorption rate constants of the sites. The desorption portion of the column breakthrough curvesmore » highlighted the importance of accounting for adsorption-desorption hysteresis (or a very nonlinear adsorption isotherm) of the Cs on the FFM in the model, and this portion of the breakthrough curves also dictated that there be at least two different types of sorption sites on the FFM. In the end, the two-site model parameters estimated from the column experiments provided excellent matches to the batch adsorption/desorption data, which provided a measure of assurance in the validity of the model.« less

In search of consolidation of short-term memory in nonhuman animals.

PubMed

Calder, Amanda; White, K Geoffrey

2014-03-01

Wixted (Annual Review of Psychology, 55, 235 – 269, 2004) has argued that forgetting is due to consolidation failure. Previous research with humans and nonhuman animals has reported evidence for consolidation in intermediate or long-term memory (LTM). The present study examines whether consolidation occurs in short-term memory in pigeons. Delayed matching-to-sample accuracy was reduced when retroactive interference (an extraneous task in Experiment 1 or houselight illumination in Experiment 2) was interpolated in the retention interval. Accuracy was not greater, however, when interference occurred at the end of the retention interval, as compared with when it occurred at the beginning. That is, there was no evidence for consolidation in short-term memory for pigeons. We did find, however, the beginning–end effect originally reported by Roberts and Grant (Journal of Experimental Psychology: Animal Behavior Processes, 4, 219–236, 1978) and the recovery from forgetting reported by White and Brown (Journal of the Experimental Analysis of Behavior, 96, 177–189, 2011). The results are discussed in relation to temporal distinctiveness theory as an alternative to consolidation.

Rumination and self-reflection in stress narratives and relations to psychological functioning.

PubMed

Marin, Kelly A; Rotondo, Elena K

2017-01-01

The longitudinal study aims to expand what is known about the costs and benefits of narrating stressful experiences by exploring changes in rumination within the narrative process and comparing it to changes in self-reflection. Rumination (e.g., brooding, self-criticism, and negative emotions) and self-reflection were measured in stress narratives of 56 college students. There were several goals: (1) examine changes in narrative rumination and narrative self-reflection over 3 days of writing, (2) examine the relations among the changes in narrative rumination variables and narrative self-reflection and (3) examine how changes in narrative rumination and narrative self-reflection relate to multiple measures of psychological functioning. Overall, individuals increased self-reflection over the 3-day writing task. Individuals who increased ruminative brooding across the 3 days of writing showed lower ego identity development (short term and long term) and self-esteem (short term), while increased self-criticism was positively correlated with identity distress (short term). Implications of the different aspects of narrative rumination, specifically in the context of stressful experiences, are discussed.

Forested wetland habitat

USGS Publications Warehouse

Duberstein, Jamie A.; Krauss, Ken W.; Kennish, Michael J.

2015-01-01

A forested wetland (swamp) is a forest where soils are saturated or flooded for at least a portion of the growing season, and vegetation, dominated by trees, is adapted to tolerate flooded conditions. A tidal freshwater forested wetland is a forested wetland that experiences frequent but short-term surface flooding via tidal action, with average salinity of soil porewater less than 0.5 g/l. It is known locally as tidal várzea in the Amazon delta, Brazil. A tidal saltwater forested wetland (mangrove forest) is a forested wetland that experiences frequent but short-term surface flooding via tidal action, with average salinity often exceeding 3 g/l and reaching levels that can exceed seawater. Mangrove ecosystems are composed of facultative halophytes that generally experience better growth at moderate salinity concentrations.

Fate of 90Sr and U(VI) in Dounreay sediments following saline inundation and erosion.

PubMed

Eagling, Jane; Worsfold, Paul J; Blake, William H; Keith-Roach, Miranda J

2013-08-01

There is concern that sea level rise associated with projected climate change will lead to the inundation, flooding and erosion of soils and sediments contaminated with radionuclides at coastal nuclear sites, such as Dounreay (UK), with seawater. Here batch and column experiments were designed to simulate these scenarios and sequential extractions were used to identify the key radionuclide solid phase associations. Strontium was exchangeable and was mobilised rapidly by ion exchange with seawater Mg(2+) in both batch and column experiments. In contrast, U was more strongly bound to the sediments and mobilisation was initially limited by the influence of the sediment on the pH of the water. Release was only observed when the pH increased above 6.9, suggesting that the formation of soluble U(VI)-carbonate species was important. Under dynamic flow conditions, long term release was significant (47%), but controlled by slow desorption kinetics from a range of binding sites. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quantifying differences in responses of aquatic insects to trace metal exposure in field studies and short-term stream mesocosm experiments

USGS Publications Warehouse

Iwasaki, Yuichi; Schmidt, Travis S.; Clements, William H.

2018-01-01

Characterizing macroinvertebrate taxa as either sensitive or tolerant is of critical importance for investigating impacts of anthropogenic stressors in aquatic ecosystems and for inferring causality. However, our understanding of relative sensitivity of aquatic insects to metals in the field and under controlled conditions in the laboratory or mesocosm experiments is limited. In this study, we compared the response of 16 lotic macroinvertebrate families to metals in short-term (10-day) stream mesocosm experiments and in a spatially extensive field study of 154 Colorado streams. Comparisons of field and mesocosm-derived EC20 (effect concentration of 20%) values showed that aquatic insects were generally more sensitive to metals in the field. Although the ranked sensitivity to metals was similar for many families, we observed large differences between field and mesocosm responses for some groups (e.g., Baetidae and Heptageniidae). These differences most likely resulted from the inability of short-term experiments to account for factors such as dietary exposure to metals, rapid recolonization in the field, and effects of metals on sensitive life stages. Understanding mechanisms responsible for differences among field, mesocosm, and laboratory approaches would improve our ability to predict contaminant effects and establish ecologically meaningful water-quality criteria.

Concreteness effects in short-term memory: a test of the item-order hypothesis.

PubMed

Roche, Jaclynn; Tolan, G Anne; Tehan, Gerald

2011-12-01

The following experiments explore word length and concreteness effects in short-term memory within an item-order processing framework. This framework asserts order memory is better for those items that are relatively easy to process at the item level. However, words that are difficult to process benefit at the item level for increased attention/resources being applied. The prediction of the model is that differential item and order processing can be detected in episodic tasks that differ in the degree to which item or order memory are required by the task. The item-order account has been applied to the word length effect such that there is a short word advantage in serial recall but a long word advantage in item recognition. The current experiment considered the possibility that concreteness effects might be explained within the same framework. In two experiments, word length (Experiment 1) and concreteness (Experiment 2) are examined using forward serial recall, backward serial recall, and item recognition. These results for word length replicate previous studies showing the dissociation in item and order tasks. The same was not true for the concreteness effect. In all three tasks concrete words were better remembered than abstract words. The concreteness effect cannot be explained in terms of an item-order trade off. PsycINFO Database Record (c) 2011 APA, all rights reserved.

Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene

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

Pennell, K.D.; Jin, M.; Abriola, L.M.

1994-01-01

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting (14)C-labeled PCE into water-saturated soil columns and displacing the free product with water. Miscible displacement experiments were conducted before and after PCE entrapment to determine the influence or residual PCE on column dispersivities. The first two column studies involved the injection of a 4% solution of polyoxyethylene (POE) (20) sorbitan monooleate, resulting in the removal of 90% and 97% of the residual PCE from 20-30- and 40-120-mesh Ottawa sand, respectively. Although micellar solubilization ofmore » PCE was the primary mode of recovery in these experiments, this process was shown to be rate-limited.« less

Competitive short-term and long-term memory processes in spatial habituation.

PubMed

Sanderson, David J; Bannerman, David M

2011-04-01

Exposure to a spatial location leads to habituation of exploration such that, in a novelty preference test, rodents subsequently prefer exploring a novel location to the familiar location. According to Wagner's (1981) theory of memory, short-term and long-term habituation are caused by separate and sometimes opponent processes. In the present study, this dual-process account of memory was tested. Mice received a series of exposure training trials to a location before receiving a novelty preference test. The novelty preference was greater when tested after a short, rather than a long, interval. In contrast, the novelty preference was weaker when exposure training trials were separated by a short, rather than a long interval. Furthermore, it was found that long-term habituation was determined by the independent effects of the amount of exposure training and the number of exposure training trials when factors such as the intertrial interval and the cumulative intertrial interval were controlled. A final experiment demonstrated that a long-term reduction of exploration could be caused by a negative priming effect due to associations formed during exploration. These results provide evidence against a single-process account of habituation and suggest that spatial habituation is determined by both short-term, recency-based memory and long-term, incrementally strengthened memory.

Uranium Sequestration During Biostimulated Reduction and In Response to the Return of Oxic Conditions In Shallow Aquifers

USGS Publications Warehouse

Fuller, Christopher C.; Johnson, Kelly J.; Akstin, Katherine; Singer, David M.; Yabusaki, Steven B.; Fang, Yilin; Fuhrmann, M.

2015-01-01

A proposed approach for groundwater remediation of uranium contamination is to generate reducing conditions by stimulating the growth of microbial populations through injection of electron donor compounds into the subsurface. Sufficiently reducing conditions will result in reduction of soluble hexavalent uranium, U(VI), and precipitation of the less soluble +4 oxidation state uranium, U(IV). This process is termed biostimulated reduction. A key issue in the remediation of uranium (U) contamination in aquifers by biostimulated reduction is the long term stability of the sequestered uranium. Three flow-through column experiments using aquifer sediment were used to evaluate the remobilization of bioreduced U sequestered under conditions in which biostimulation extended well into sulfate reduction to enhance precipitation of reduced sulfur phases such as iron sulfides. One column received added ferrous iron, Fe(II), increasing production of iron sulfides, to test their effect on remobilization of the sequestered uranium, either by serving as a redox buffer by competing for dissolved oxygen, or by armoring the reduced uranium. During biostimulation of the ambient microbial population with acetate, dissolved uranium was lowered by a factor of 2.5 or more with continued removal for over 110 days of biostimulation, well after the onset of sulfate reduction at ~30 days. Sequestered uranium was essentially all U(IV) resulting from the formation of nano-particulate uraninite that coated sediment grains to a thickness of a few 10’s of microns, sometimes in association with S and Fe. A multicomponent biogeochemical reactive transport model simulation of column effluents during biostimulation was generally able to describe the acetate oxidation, iron, sulfate, and uranium reduction for all three columns using parameters derived from simulations of field scale biostimulation experiments. Columns were eluted with artificial groundwater at equilibrium with atmospheric oxygen to simulate the upper limit of dissolved oxygen in recharge water. Overall about 9% of total uranium removed from solution during biostimulation was remobilized. Release of U during oxic elution was a continuous process over 140 days with dissolved uranium concentrations about 0.2 and 0.8 aM for columns with and without ferrous iron addition, respectively. Uranium remaining on the sediment was in the reduced form. The prolonged period of biostimulation and concomitant sulfate reduction appears to limit the rate of U(IV) oxidative remobilization in contrast to a large release observed for columns in previous studies that did not undergo sulfate reduction. Although continued sulfate reduction may cause decreased permeability from precipitation of iron sulfide, the greater apparent stability of the sequestered U(IV) provided by the sustained biostimulation should be considered in design of field scale remediation efforts. Remobilization of uranium following biostimulated reduction should be tested further at the field scale.

Individual Differences in Arousal and Their Relationship to Short- and Long-Term Retention. Report From the Project on Motivation and Individual Differences in Learning and Retention.

ERIC Educational Resources Information Center

Osborne, John W.; Farley, Frank H.

In two separate paired-associate learning experiments each employing 40 university students as subjects, the contribution of individual differences (IDs) in arousal to short- and long-term retention was investigated using IDs in salivary response to lemon juice stimulation as an index of arousal. Experimental subjects were pre-selected out of 184…

Short- versus long-term responses to changing CO2 in a coastal dinoflagellate bloom: implications for interspecific competitive interactions and community structure.

PubMed

Tatters, Avery O; Schnetzer, Astrid; Fu, Feixue; Lie, Alle Y A; Caron, David A; Hutchins, David A

2013-07-01

Increasing pCO2 (partial pressure of CO2 ) in an "acidified" ocean will affect phytoplankton community structure, but manipulation experiments with assemblages briefly acclimated to simulated future conditions may not accurately predict the long-term evolutionary shifts that could affect inter-specific competitive success. We assessed community structure changes in a natural mixed dinoflagellate bloom incubated at three pCO2 levels (230, 433, and 765 ppm) in a short-term experiment (2 weeks). The four dominant species were then isolated from each treatment into clonal cultures, and maintained at all three pCO2 levels for approximately 1 year. Periodically (4, 8, and 12 months), these pCO2 -conditioned clones were recombined into artificial communities, and allowed to compete at their conditioning pCO2 level or at higher and lower levels. The dominant species in these artificial communities of CO2 -conditioned clones differed from those in the original short-term experiment, but individual species relative abundance trends across pCO2 treatments were often similar. Specific growth rates showed no strong evidence for fitness increases attributable to conditioning pCO2 level. Although pCO2 significantly structured our experimental communities, conditioning time and biotic interactions like mixotrophy also had major roles in determining competitive outcomes. New methods of carrying out extended mixed species experiments are needed to accurately predict future long-term phytoplankton community responses to changing pCO2 . © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Short Intervention, Sustained Effects: Promoting Students' Math Competence Beliefs, Effort, and Achievement

ERIC Educational Resources Information Center

Brisson, Brigitte Maria; Dicke, Anna-Lena; Gaspard, Hanna; Häfner, Isabelle; Flunger, Barbara; Nagengast, Benjamin; Trautwein, Ulrich

2017-01-01

The present study investigated the effectiveness of two short relevance interventions (writing a text or evaluating quotations about the utility of mathematics) using a sample of 1,916 students in 82 math classrooms in a cluster randomized controlled experiment. Short-term and sustained effects (6 weeks and 5 months after the intervention) of the…

Estimation of desmosponge (Porifera, Demospongiae) larval settlement rates from short-term recruitment rates: Preliminary experiments

NASA Astrophysics Data System (ADS)

Zea, Sven

1992-09-01

During a study of the spatial and temporal patterns of desmosponge (Porifera, Demospongiae) recruitment on rocky and coral reef habitats of Santa Marta, Colombian Caribbean Sea, preliminary attempts were made to estimate actual settlement rates from short-term (1 to a few days) recruitment censuses. Short-term recruitment rates on black, acrylic plastic plates attached to open, non-cryptic substratum by anchor screws were low and variable (0 5 recruits/plate in 1 2 days, sets of n=5 10 plates), but reflected the depth and seasonal trends found using mid-term (1 to a few months) censusing intervals. Moreover, mortality of recruits during 1 2 day intervals was low (0 12%). Thus, short-term censusing intervals can be used to estimate actual settlement rates. To be able to make statistical comparisons, however, it is necessary to increase the number of recruits per census by pooling data of n plates per set, and to have more than one set per site or treatment.

Automatic attention towards face or body as a function of mating motivation.

PubMed

Lu, Hui Jing; Chang, Lei

2012-03-22

Because women's faces and bodies carry different cues of reproductive value, men may attend to different perceptual cues as functions of their long-term versus short-term mating motivations. We tested this hypothesis in three experiments on 135 male and 132 female participants. When influenced by short-term rather than long-term mating motivations, men's attention was captured by (Study 1), was shifted to (Study 2), and was distracted by (Study 3) the waist/hip area rather than the face on photographs of attractive women. Similar effects were not found among the female participants in response to photographs of attractive men. These results support the evolutionary view that, similar to the attentional selectivity found in other domains of life, male perceptual attention has evolved to selectively capture and hold reproductive information about the opposite sex as a function of short-term versus long-term mating goals.

Reliability of high I/O high density CCGA interconnect electronic packages under extreme thermal environments

NASA Astrophysics Data System (ADS)

Ramesham, Rajeshuni

2012-03-01

Ceramic column grid array (CCGA) packages have been increasing in use based on their advantages such as high interconnect density, very good thermal and electrical performances, compatibility with standard surfacemount packaging assembly processes, and so on. CCGA packages are used in space applications such as in logic and microprocessor functions, telecommunications, payload electronics, and flight avionics. As these packages tend to have less solder joint strain relief than leaded packages or more strain relief over lead-less chip carrier packages, the reliability of CCGA packages is very important for short-term and long-term deep space missions. We have employed high density CCGA 1152 and 1272 daisy chained electronic packages in this preliminary reliability study. Each package is divided into several daisy-chained sections. The physical dimensions of CCGA1152 package is 35 mm x 35 mm with a 34 x 34 array of columns with a 1 mm pitch. The dimension of the CCGA1272 package is 37.5 mm x 37.5 mm with a 36 x 36 array with a 1 mm pitch. The columns are made up of 80% Pb/20%Sn material. CCGA interconnect electronic package printed wiring polyimide boards have been assembled and inspected using non-destructive x-ray imaging techniques. The assembled CCGA boards were subjected to extreme temperature thermal atmospheric cycling to assess their reliability for future deep space missions. The resistance of daisy-chained interconnect sections were monitored continuously during thermal cycling. This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non-destructive inspection tools were used to assess the reliability of high density CCGA packages for deep space extreme temperature missions.

Modeling Bimolecular Reactive Transport With Mixing-Limitation: Theory and Application to Column Experiments

NASA Astrophysics Data System (ADS)

Ginn, T. R.

2018-01-01

The challenge of determining mixing extent of solutions undergoing advective-dispersive-diffusive transport is well known. In particular, reaction extent between displacing and displaced solutes depends on mixing at the pore scale, that is, generally smaller than continuum scale quantification that relies on dispersive fluxes. Here a novel mobile-mobile mass transfer approach is developed to distinguish diffusive mixing from dispersive spreading in one-dimensional transport involving small-scale velocity variations with some correlation, such as occurs in hydrodynamic dispersion, in which short-range ballistic transports give rise to dispersed but not mixed segregation zones, termed here ballisticules. When considering transport of a single solution, this approach distinguishes self-diffusive mixing from spreading, and in the case of displacement of one solution by another, each containing a participant reactant of an irreversible bimolecular reaction, this results in time-delayed diffusive mixing of reactants. The approach generates models for both kinetically controlled and equilibrium irreversible reaction cases, while honoring independently measured reaction rates and dispersivities. The mathematical solution for the equilibrium case is a simple analytical expression. The approach is applied to published experimental data on bimolecular reactions for homogeneous porous media under postasymptotic dispersive conditions with good results.

Temporal framing and consideration of future consequences: effects on smokers' and at-risk nonsmokers' responses to cigarette health warnings.

PubMed

Zhao, Xiaoquan; Nan, Xiaoli; Iles, Irina Alexandra; Yang, Bo

2015-01-01

This research examines the influence of temporal framing (long-term vs. short-term) and individual difference in consideration of future consequences (CFC) on the effectiveness of cigarette health warnings among smokers and at-risk nonsmokers in a college population. An online experiment (N = 395) revealed a three-way interaction among temporal framing, CFC, and smoking status. The results among at-risk nonsmokers supported the temporal fit hypothesis--those high in CFC responded more favorably to long-term framing, whereas those low in CFC responded more positively to short-term framing. The findings among smokers revealed a different pattern in which short-term framing was more effective among high-CFC smokers, whereas among low-CFC smokers the framing effect was not distinct. Theoretical and practical implications of the findings are discussed.

Complex network structure influences processing in long-term and short-term memory.

PubMed

Vitevitch, Michael S; Chan, Kit Ying; Roodenrys, Steven

2012-07-01

Complex networks describe how entities in systems interact; the structure of such networks is argued to influence processing. One measure of network structure, clustering coefficient, C, measures the extent to which neighbors of a node are also neighbors of each other. Previous psycholinguistic experiments found that the C of phonological word-forms influenced retrieval from the mental lexicon (that portion of long-term memory dedicated to language) during the on-line recognition and production of spoken words. In the present study we examined how network structure influences other retrieval processes in long- and short-term memory. In a false-memory task-examining long-term memory-participants falsely recognized more words with low- than high-C. In a recognition memory task-examining veridical memories in long-term memory-participants correctly recognized more words with low- than high-C. However, participants in a serial recall task-examining redintegration in short-term memory-recalled lists comprised of high-C words more accurately than lists comprised of low-C words. These results demonstrate that network structure influences cognitive processes associated with several forms of memory including lexical, long-term, and short-term.

Determining Whether a Definitive Causal Relationship Exists Between Aripiprazole and Tardive Dyskinesia and/or Dystonia in Patients With Major Depressive Disorder, Part 3: Clinical Trial Data.

PubMed

Preskorn, Sheldon H; Macaluso, Matthew

2016-03-01

This series of columns has 3 main goals: (1) to explain class warnings as used by the United States Food and Drug Administration, (2) to increase awareness of movement disorders that may occur in patients treated with antipsychotic medications, and (3) to understand why clinicians should refrain from immediately assuming a diagnosis of tardive dyskinesia/dystonia (TD) in patients who develop abnormal movements during treatment with antipsychotics. The first column in the series presented a patient who developed abnormal movements while being treated with aripiprazole as an augmentation strategy for major depressive disorder (MDD) and reviewed data concerning the historical background, incidence, prevalence, and risk factors for tardive and spontaneous dyskinesias, the clinical presentations of which closely resemble each other. The second column in the series reviewed the unique mechanism of action of aripiprazole and preclinical studies and an early-phase human translational study that suggest a low, if not absent, risk of TD with aripiprazole. This column reviews clinical trial data to assess whether those data support the conclusion that aripiprazole has a low to absent risk of causing TD when used as an augmentation strategy to treat MDD. To date, no randomized, placebo-controlled trials have established a definitive link between exposure to aripiprazole and TD in patients with MDD. One long-term, open-label, safety trial examined aripiprazole as an augmentation strategy in individuals with MDD and found a rare occurrence (4/987, 0.4%, the confidence interval of which overlaps with zero) of an adverse event termed TD. In all 4 cases, the observed movements resolved within weeks of aripiprazole discontinuation, suggesting that they were either amenable to treatment or represented an acute syndrome rather than TD. No cases of TD were reported in the registration trials for the MDD indication for aripiprazole. These data were presented in a pooled analysis of three, 14-week studies involving 1088 subjects, 409 of whom were elderly like the 76-year-old individual presented in the case in the first column of this series. Finally, 3 short-term studies evaluated the use of aripiprazole in patients with psychosis associated with Alzheimer disease, a population who would be considered a relatively higher risk group for developing TD when exposed to antipsychotics and that also closely matches the patient in the case presented at the beginning of this series in terms of age. No incidence of TD was reported in this sample and mean scores on the Abnormal Involuntary Movement Scale decreased in individuals exposed to aripiprazole compared with those on placebo. On the basis of results of this review and data from registration trials of aripiprazole for all indications, the potential (or raw) incidence of what was termed TD occurred at rates ranging from 0.004 (4/987) based on long-term safety data from the program investigating aripiprazole augmentation treatment in MDD, to 0.0016 (19/11,897) based on the total safety database from aripiprazole registration trials for all indications, to 0 in trials in elderly individuals with Alzheimer disease. The confidence intervals for all of these potential incidence rates overlap with zero. The next column in this 5-part series reviews 37 case reports that reported TD in association with aripiprazole treatment and 27 case reports that suggested an improvement in preexisting TD with aripiprazole treatment. The fifth and final column in this series will discuss the types of prohibitively expensive and logistically difficult studies that would be needed to determine whether a definitive causal relationship between aripiprazole and TD exists.

Beyond Medical "Missions" to Impact-Driven Short-Term Experiences in Global Health (STEGHs): Ethical Principles to Optimize Community Benefit and Learner Experience.

PubMed

Melby, Melissa K; Loh, Lawrence C; Evert, Jessica; Prater, Christopher; Lin, Henry; Khan, Omar A

2016-05-01

Increasing demand for global health education in medical training has driven the growth of educational programs predicated on a model of short-term medical service abroad. Almost two-thirds of matriculating medical students expect to participate in a global health experience during medical school, continuing into residency and early careers. Despite positive intent, such short-term experiences in global health (STEGHs) may exacerbate global health inequities and even cause harm. Growing out of the "medical missions" tradition, contemporary participation continues to evolve. Ethical concerns and other disciplinary approaches, such as public health and anthropology, can be incorpo rated to increase effectiveness and sustainability, and to shift the culture of STEGHs from focusing on trainees and their home institutions to also considering benefits in host communities and nurtur ing partnerships. The authors propose four core principles to guide ethical development of educational STEGHs: (1) skills building in cross-cultural effective ness and cultural humility, (2) bidirectional participatory relationships, (3) local capacity building, and (4) long-term sustainability. Application of these principles highlights the need for assessment of STEGHs: data collection that allows transparent compar isons, standards of quality, bidirectionality of agreements, defined curricula, and ethics that meet both host and sending countries' standards and needs. To capture the enormous potential of STEGHs, a paradigm shift in the culture of STEGHs is needed to ensure that these experiences balance training level, personal competencies, medical and cross-cultural ethics, and educational objectives to minimize harm and maximize benefits for all involved.

Effect of concentration gradients on biodegradation in bench-scale sand columns with HYDRUS modeling of hydrocarbon transport and degradation.

PubMed

Horel, Agota; Schiewer, Silke; Misra, Debasmita

2015-09-01

The present research investigated to what extent results obtained in small microcosm experiments can be extrapolated to larger settings with non-uniform concentrations. Microbial hydrocarbon degradation in sandy sediments was compared for column experiments versus homogenized microcosms with varying concentrations of diesel, Syntroleum, and fish biodiesel as contaminants. Syntroleum and fish biodiesel had higher degradation rates than diesel fuel. Microcosms showed significantly higher overall hydrocarbon mineralization percentages (p < 0.006) than columns. Oxygen levels and moisture content were likely not responsible for that difference, which could, however, be explained by a strong gradient of fuel and nutrient concentrations through the column. The mineralization percentage in the columns was similar to small-scale microcosms at high fuel concentrations. While absolute hydrocarbon degradation increased, mineralization percentages decreased with increasing fuel concentration which was corroborated by saturation kinetics; the absolute CO2 production reached a steady plateau value at high substrate concentrations. Numerical modeling using HYDRUS 2D/3D simulated the transport and degradation of the investigated fuels in vadose zone conditions similar to those in laboratory column experiments. The numerical model was used to evaluate the impact of different degradation rate constants from microcosm versus column experiments.

Innervation zone shift at different levels of isometric contraction in the biceps brachii muscle.

PubMed

Piitulainen, Harri; Rantalainen, Timo; Linnamo, Vesa; Komi, Paavo; Avela, Janne

2009-08-01

Experiments were carried out to examine whether innervation zone (IZ) location remains stable at different levels of isometric contraction in the biceps brachii muscle (BB), and to determine how the proximity of the IZ affects common surface electromyography (sEMG) parameters. Twelve subjects performed maximal (MVC) and submaximal voluntary isometric contractions at 10%, 20%, 30%, 40%, 50% and 75% of MVC. sEMG signals were recorded with a 13 rows x 5 columns grid of electrodes from the short head of BB. The IZ shifted in the proximal direction by up to 2.4 cm, depending upon the subject and electrode column. The mean shift of all the columns was 0.6+/-0.4 cm (10% vs. 100% MVC, P<0.001). This shift biased the average values of mean frequency (+21.8+/-9.9 Hz, P<0.001), root mean square (-0.16+/-0.15 mV, P<0.05) and conduction velocity (-1.15+/-0.93 m/s, P<0.01) in the channels immediately proximal to the IZ. The shift in IZ could be explained by shortening of the muscle fibers, and thus lengthening of the (distal) tendon due to increasing force. These results underline the importance of individual investigation of IZ locations before the placement of sEMG electrodes, even in isometric contractions.

Impact of the temporal variation of oxygen contents in the water column on the biogeochemistry of the benthic zone

NASA Astrophysics Data System (ADS)

Rigaud, Sylvain; Deflandre, Bruno; Grenz, Christian; Pozzato, Lara; Cesbron, Florian; Meulé, Samuel; Bonin, Patricia; Michotey, Valérie; Mirleau, Pascal; Mirleau, Fatma; Knoery, Joel; Zuberer, Frédéric; Guillemain, Dorian; Marguerite, Sébatien; Mayot, Nicolas; Faure, Vincent; Grisel, Raphael; Radakovitch, Olivier

2017-04-01

The desoxygenation of the water column in coastal areas, refered as coastal hypoxia, is currently a growing phenomenon still particularly complex to predict. This is mainly due to the fact that the biogeochemical response of the benthic ecosystem to the variation of the oxygen contents in the water column remains poorly understood. Dissolved oxygen concentration is a key parameter controling the benthic micro- and macro-community as well as the biogeochemical reactions occuring in the surface sediment. More particularly, the variation over variable time scales (from hour to years) of the oxygen deficit may induce different pathways for biogeochemical processes such as the oxydation of freshly deposited organic matter and nutrients and metals recycling. This results in variable chemical fluxes at the sediment-water interface, that may in turn, support the eutrophication and desoxygenation of the aquatic system. Our study focus on the Berre lagoon, an eutrophicated mediterranean lagoon impacted by hypoxia events in the water column. Three stations, closely located but impacted by contrasted temporal variation of oxygen deficit in the water column were selected: one station with rare oxygen deficit and with functionnal macrofauna community, one station with almost permanent oxygen deficit and no macrofauna community and one intermediate station with seasonnal oxygen deficit and degraded macrofauna community. Each station was surveyed once during a same field survey while the intermediate station was surveyed seasonnaly. For each campaign, we report vertical profiles of the main chemical components (oxygen, nutrients, metals) along the water-column/sediment continuum, with an increased vertical resolution in the benthic zone using a multi-tool approach (high vertical resolution suprabenthic water sampler and microsensors profiler). In addition, total chemical fluxes at the sediment-water interface was obtained using benthic chambers. This dataset was used to evaluate the influence, of the oxygen concentrations (and its short and long-term variations) in the water column on the nature and location of the main biogeochemical reactions occuring in the benthic zone and the resulting fluxes at the sediment-water interface.

Short-term fate of intertidal microphytobenthos carbon under enhanced nutrient availability: a 13C pulse-chase experiment

NASA Astrophysics Data System (ADS)

Riekenberg, Philip M.; Oakes, Joanne M.; Eyre, Bradley D.

2018-05-01

Shallow coastal waters in many regions are subject to nutrient enrichment. Microphytobenthos (MPB) can account for much of the carbon (C) fixation in these environments, depending on the depth of the water column, but the effect of enhanced nutrient availability on the processing and fate of MPB-derived C (MPB-C) is relatively unknown. In this study, MPB was labeled (stable isotope enrichment) in situ using 13C-sodium bicarbonate. The processing and fate of the newly fixed MPB-C was then traced using ex situ incubations over 3.5 days under different concentrations of nutrients (NH4+ and PO43-: ambient, 2 × ambient, 5 × ambient, and 10 × ambient). After 3.5 days, sediments incubated with increased nutrient concentrations (amended treatments) had increased loss of 13C from sediment organic matter (OM) as a portion of initial uptake (95 % remaining in ambient vs. 79-93 % for amended treatments) and less 13C in MPB (52 % ambient, 26-49 % amended), most likely reflecting increased turnover of MPB-derived C supporting increased production of extracellular enzymes and storage products. Loss of MPB-derived C to the water column via dissolved organic C (DOC) was minimal regardless of treatment (0.4-0.6 %). Loss due to respiration was more substantial, with effluxes of dissolved inorganic C (DIC) increasing with additional nutrient availability (4 % ambient, 6.6-19.8 % amended). These shifts resulted in a decreased turnover time for algal C (419 days ambient, 134-199 days amended). This suggests that nutrient enrichment of estuaries may ultimately lead to decreased retention of carbon within MPB-dominated sediments.

Single application of Sewage Sludge to an Alluvial Agricultural Soil - impacts on Soil Quality

NASA Astrophysics Data System (ADS)

Suhadolc, M.; Graham, D. B.; Hagn, A.; Doerfler, U.; Schloter, M.; Schroll, R.; Munch, J. C.; Lobnik, F.

2009-04-01

Limited information exists on the effects of sewage sludge on soil quality with regard to their ability to maintain soil functions. We studied effects of sewage sludge amendment on soil chemical properties, microbial community structure and microbial degradation of the herbicide glyphosate. Three months soil column leaching experiment has been conducted using alluvial soils (Eutric Fluvisol) with no prior history of sludge application. The soil was loamy with pH 7,4 and organic matter content of 3,5%. Soil material in the upper 2 cm of columns was mixed with dehydrated sewage sludge which was applied in amounts corresponding to the standards governing the use of sewage sludge for agricultural land. Sludge did increase some nutrients (total N, NH4+, available P and K, organic carbon) and some heavy metals contents (Zn, Cu, Pb) in soil. However, upper limits for heavy metals in agricultural soils were not exceeded. Results of heavy metal availability in soil determined by sequential extraction will be also presented. Restriction fragment length polymorphism (RFLP) analyses of 16s/18s rDNA, using universal fungal and bacterial primers, revealed clear shifts in bacterial and fungal community structure in the upper 2 cm of soils after amendment. Fungal fingerprints showed greater short term effects of sewage sludge, whereas sewage sludge seems to have prolonged effects on soil bacteria. Furthermore, sewage sludge amendment significantly increased glyphosate degradation from 21.6±1% to 33.6±1% over a 2 months period. The most probable reasons for shifts in microbial community structure and increased degradation of glyphosate are beneficial alterations to the physical-chemical characteristics of the soil. Negative effects of potentially toxic substances present in the sewage sludge on soil microbial community functioning were not observed with the methods used in our study.

Assessing the Short-Term Global Health Experience: A Cross-Sectional Study of Demographics, Socioeconomic Factors, and Disease Prevalence.

PubMed

Geen, Olivia; Pumputis, Allison; Kochi, Cristina; Costa, Andrew; Stobbe, Karl

2017-08-01

Interest in short-term global health experiences to underserviced populations has grown rapidly in the last few decades. However, there remains very little research on what participants can expect to encounter. At the same time, it has been suggested that in order for physicians and workers to provide safe and effective care, volunteers should have a basic understanding of local culture, health systems, epidemiology, and socioeconomic needs of the community before arriving. Our objective was to add to the limited literature on what short-term global health trips can expect to encounter through a cross-sectional study of patient demographics, socioeconomic markers, and the prevalence of diseases encountered on a short-term medical service trip to Lima, Peru. Descriptive analysis was conducted on clinic data collected from patients living in Pamplona Alta and Pamplona Baja, Lima, Peru, in July 2015. We found that volunteers encountered mainly female patients (70.8%), and that there were significant socioeconomic barriers to care including poverty, poor housing, environmental exposures, and lack of continuity of health care. Analysis of the disease prevalence found a high proportion of acute and chronic musculoskeletal pain in the adult populations (18.8% and 11.4%, respectively), and a high presentation of upper respiratory tract infections (25.4%) and parasites (22.0%) in the pediatric group. These findings can be used by future short-term medical service trips to address potential gaps in care including the organization of weekend clinics to allow access to working men, and the use of patient education and nonpharmacological management of acute and chronic disease.

The impact of recombination on short-term selection gain in plant breeding experiments.

PubMed

McClosky, Benjamin; Tanksley, Steven D

2013-09-01

Recombination is a requirement for response to selection, but researchers still debate whether increasing recombination beyond normal levels will result in significant gains in short-term selection. We tested this hypothesis, in the context of plant breeding, through a series of simulation experiments comparing short-term selection response (≤20 cycles) between populations with normal levels of recombination and similar populations with unconstrained recombination (i.e., free recombination). We considered additive and epistatic models and examined a wide range of values for key design variables: selection cycles, QTL number, heritability, linkage phase, selection intensity and population size. With few exceptions, going from normal to unconstrained levels of recombination produced only modest gains in response to selection (≈11 % on average). We then asked how breeders might capture some of this theoretical gain by increasing recombination through either (1) extra rounds of mating or (2) selection of highly recombinant individuals via use of molecular markers/maps. All methods tested captured less than half of the potential gain, but our analysis indicates that the most effective method is to select for increased recombination and the trait simultaneously. This recommendation is based on evidence of a favorable interaction between trait selection and the impact of recombination on selection gains. Finally, we examined the relative contributions of the two components of meiotic recombination, chromosome assortment and crossing over, to short-term selection gain. Depending primarily on the presence of trait selection pressure, chromosome assortment alone accounted for 40-75 % of gain in response to short-term selection.

Long-term nitrogen addition affects the phylogenetic turnover of soil microbial community responding to moisture pulse

DOE PAGES

Liu, Chi; Yao, Minjie; Stegen, James C.; ...

2017-12-13

How press disturbance (long-term) influences the phylogenetic turnover of soil microbial communities responding to pulse disturbances (short-term) is not fully known. Understanding the complex connections between the history of environmental conditions, assembly processes and microbial community dynamics is necessary to predict microbial response to perturbation. Here, we started by investigating phylogenetic spatial turnover (based on DNA) of soil prokaryotic communities after long-term nitrogen (N) deposition and temporal turnover (based on RNA) of communities responding to pulse by conducting short-term rewetting experiments. The results showed that moderate N addition increased ecological stochasticity and phylogenetic diversity. In contrast, high N addition slightlymore » increased homogeneous selection and decreased phylogenetic diversity. Examining the system with higher phylogenetic resolution revealed a moderate contribution of variable selection across the whole N gradient. The moisture pulse experiment showed that high N soils had higher rates of phylogenetic turnover across short phylogenetic distances and significant changes in community compositions through time. Long-term N input history influenced spatial turnover of microbial communities, but the dominant community assembly mechanisms differed across different N deposition gradients. We further revealed an interaction between press and pulse disturbances whereby deterministic processes were particularly important following pulse disturbances in high N soils.« less

Long-term nitrogen addition affects the phylogenetic turnover of soil microbial community responding to moisture pulse

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

Liu, Chi; Yao, Minjie; Stegen, James C.

How press disturbance (long-term) influences the phylogenetic turnover of soil microbial communities responding to pulse disturbances (short-term) is not fully known. Understanding the complex connections between the history of environmental conditions, assembly processes and microbial community dynamics is necessary to predict microbial response to perturbation. Here, we started by investigating phylogenetic spatial turnover (based on DNA) of soil prokaryotic communities after long-term nitrogen (N) deposition and temporal turnover (based on RNA) of communities responding to pulse by conducting short-term rewetting experiments. The results showed that moderate N addition increased ecological stochasticity and phylogenetic diversity. In contrast, high N addition slightlymore » increased homogeneous selection and decreased phylogenetic diversity. Examining the system with higher phylogenetic resolution revealed a moderate contribution of variable selection across the whole N gradient. The moisture pulse experiment showed that high N soils had higher rates of phylogenetic turnover across short phylogenetic distances and significant changes in community compositions through time. Long-term N input history influenced spatial turnover of microbial communities, but the dominant community assembly mechanisms differed across different N deposition gradients. We further revealed an interaction between press and pulse disturbances whereby deterministic processes were particularly important following pulse disturbances in high N soils.« less

Long-term nitrogen addition affects the phylogenetic turnover of soil microbial community responding to moisture pulse.

PubMed

Liu, Chi; Yao, Minjie; Stegen, James C; Rui, Junpeng; Li, Jiabao; Li, Xiangzhen

2017-12-13

How press disturbance (long-term) influences the phylogenetic turnover of soil microbial communities responding to pulse disturbances (short-term) is not fully known. Understanding the complex connections between the history of environmental conditions, assembly processes and microbial community dynamics is necessary to predict microbial response to perturbation. We started by investigating phylogenetic spatial turnover (based on DNA) of soil prokaryotic communities after long-term nitrogen (N) deposition and temporal turnover (based on RNA) of communities responding to pulse by conducting short-term rewetting experiments. The results showed that moderate N addition increased ecological stochasticity and phylogenetic diversity. In contrast, high N addition slightly increased homogeneous selection and decreased phylogenetic diversity. Examining the system with higher phylogenetic resolution revealed a moderate contribution of variable selection across the whole N gradient. The moisture pulse experiment showed that high N soils had higher rates of phylogenetic turnover across short phylogenetic distances and significant changes in community compositions through time. Long-term N input history influenced spatial turnover of microbial communities, but the dominant community assembly mechanisms differed across different N deposition gradients. We further revealed an interaction between press and pulse disturbances whereby deterministic processes were particularly important following pulse disturbances in high N soils.

Short-term pre- and post-operative stress prolongs incision-induced pain hypersensitivity without changing basal pain perception.

PubMed

Cao, Jing; Wang, Po-Kai; Tiwari, Vinod; Liang, Lingli; Lutz, Brianna Marie; Shieh, Kun-Ruey; Zang, Wei-Dong; Kaufman, Andrew G; Bekker, Alex; Gao, Xiao-Qun; Tao, Yuan-Xiang

2015-12-02

Chronic stress has been reported to increase basal pain sensitivity and/or exacerbate existing persistent pain. However, most surgical patients have normal physiological and psychological health status such as normal pain perception before surgery although they do experience short-term stress during pre- and post-operative periods. Whether or not this short-term stress affects persistent postsurgical pain is unclear. In this study, we showed that pre- or post-surgical exposure to immobilization 6 h daily for three consecutive days did not change basal responses to mechanical, thermal, or cold stimuli or peak levels of incision-induced hypersensitivity to these stimuli; however, immobilization did prolong the duration of incision-induced hypersensitivity in both male and female rats. These phenomena were also observed in post-surgical exposure to forced swimming 25 min daily for 3 consecutive days. Short-term stress induced by immobilization was demonstrated by an elevation in the level of serum corticosterone, an increase in swim immobility, and a decrease in sucrose consumption. Blocking this short-term stress via intrathecal administration of a selective glucocorticoid receptor antagonist, RU38486, or bilateral adrenalectomy significantly attenuated the prolongation of incision-induced hypersensitivity to mechanical, thermal, and cold stimuli. Our results indicate that short-term stress during the pre- or post-operative period delays postoperative pain recovery although it does not affect basal pain perception. Prevention of short-term stress may facilitate patients' recovery from postoperative pain.

Short-term memory binding deficits in Alzheimer's disease.

PubMed

Parra, Mario A; Abrahams, Sharon; Fabi, Katia; Logie, Robert; Luzzi, Simona; Della Sala, Sergio

2009-04-01

Alzheimer's disease impairs long term memories for related events (e.g. faces with names) more than for single events (e.g. list of faces or names). Whether or not this associative or 'binding' deficit is also found in short-term memory has not yet been explored. In two experiments we investigated binding deficits in verbal short-term memory in Alzheimer's disease. Experiment 1: 23 patients with Alzheimer's disease and 23 age and education matched healthy elderly were recruited. Participants studied visual arrays of objects (six for healthy elderly and four for Alzheimer's disease patients), colours (six for healthy elderly and four for Alzheimer's disease patients), unbound objects and colours (three for healthy elderly and two for Alzheimer's disease patients in each of the two categories), or objects bound with colours (three for healthy elderly and two for Alzheimer's disease patients). They were then asked to recall the items verbally. The memory of patients with Alzheimer's disease for objects bound with colours was significantly worse than for single or unbound features whereas healthy elderly's memory for bound and unbound features did not differ. Experiment 2: 21 Alzheimer's disease patients and 20 matched healthy elderly were recruited. Memory load was increased for the healthy elderly group to eight items in the conditions assessing memory for single or unbound features and to four items in the condition assessing memory for the binding of these features. For Alzheimer's disease patients the task remained the same. This manipulation permitted the performance to be equated across groups in the conditions assessing memory for single or unbound features. The impairment in Alzheimer's disease patients in recalling bound objects reported in Experiment 1 was replicated. The binding cost was greater than that observed in the healthy elderly group, who did not differ in their performance for bound and unbound features. Alzheimer's disease grossly impairs the mechanisms responsible for holding integrated objects in verbal short-term memory.

Hardware and software for automating the process of studying high-speed gas flows in wind tunnels of short-term action

NASA Astrophysics Data System (ADS)

Yakovlev, V. V.; Shakirov, S. R.; Gilyov, V. M.; Shpak, S. I.

2017-10-01

In this paper, we propose a variant of constructing automation systems for aerodynamic experiments on the basis of modern hardware-software means of domestic development. The structure of the universal control and data collection system for performing experiments in wind tunnels of continuous, periodic or short-term action is proposed. The proposed hardware and software development tools for ICT SB RAS and ITAM SB RAS, as well as subsystems based on them, can be widely applied to any scientific and experimental installations, as well as to the automation of technological processes in production.

The top ten list: lessons learned from teaching a study abroad course.

PubMed

Kostovich, Carol T; Bermele, Charlene A

2011-01-01

In response to the need for culturally competent care, faculty can instill in students the desire to become culturally competent practitioners by providing the opportunity to participate in a short-term study abroad immersion experience. While this strategy is not considered cutting-edge or revolutionary, changing global dynamics warrant rethinking this curricular option. Nurse faculty conducted two short-term study abroad courses in Croatia. Students explored health care and nursing education in this Eastern European country and participated in a service-learning project. Based on their experiences, the authors offer five dos and five don'ts for planning and implementing a successful study abroad course.

Characterization and applications of reversed-phase column selectivity based on the hydrophobic-subtraction model.

PubMed

Marchand, D H; Snyder, L R; Dolan, J W

2008-05-16

A total of 371 reversed-phase columns have now been characterized in terms of selectivity, based on five solute-column interactions (the hydrophobic-subtraction model). The present study illustrates the use of these data for interpreting peak-tailing and column stability. New insights are also provided concerning column selectivity as a function of ligand and silica type, and the selection of columns for orthogonal separations is re-examined. Some suggestions for the quality control of reversed-phase columns during manufacture are offered.

Interpretation of actinide-distribution data obtained from non-destructive and destructive post-test analyses of an intact-core column of Culebra dolomite.

PubMed

Perkins, W G; Lucero, D A

2001-02-01

The US Department of Energy (DOE), with technical assistance from Sandia National Laboratories, has successfully received EPA certification and opened the Waste Isolation Pilot Plant (WIPP), a nuclear waste disposal facility located approximately 42 km east of Carlsbad, NM. Performance assessment (PA) analyses indicate that human intrusions by inadvertent, intermittent drilling for resources provide the only credible mechanisms for significant releases of radionuclides from the disposal system. For long-term brine releases, migration pathways through the permeable layers of rock above the Salado formation are important. Major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer overlying the WIPP site. In order to help quantify parameters for the calculated releases, radionuclide transport experiments have been carried out using intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the WIPP site. This paper deals primarily with results of analyses for 241Pu and 241Am distributions developed during transport experiments in one of these cores. Transport experiments were done using a synthetic brine that simulates Culebra brine at the core recovery location (the WIPP air-intake shaft (AIS)). Hydraulic characteristics (i.e., apparent porosity and apparent dispersion coefficient) for intact-core columns were obtained via experiments using the conservative tracer 22Na. Elution experiments carried out over periods of a few days with tracers 232U and 239Np indicated that these tracers were weakly retarded as indicated by delayed elution of the species. Elution experiments with tracers 241Pu and 241Am were attempted but no elution of either species has been observed to date, including experiments of many months' duration. In order to quantify retardation of the non-eluted species 241Pu and 241Am after a period of brine flow, non-destructive and destructive analyses of one intact-core column were carried out to determine distribution of these actinides in the rock. Analytical results indicate that the majority of the 241Am remained very near the injection surface of the core (possibly as a precipitate), and that the majority of the 241Pu was dispersed with a very high apparent retardation value. The 241Pu distribution is interpreted using a single-porosity advection-dispersion model, and an approximate retardation value is reported.

Influence of Short-Term Study Abroad Experiences on Community Health Baccalaureate Students.

PubMed

Phillips, Lynelle; Bloom, Tina; Gainey, Tammie; Chiocca, Ellen

2017-09-01

Very short study abroad programs may be most feasible in undergraduate nursing programs, but little research describes their value for prospective nurses. The narratives of senior baccalaureate nursing students (N = 62) who traveled for 2 weeks to Cape Coast, Ghana, between semesters for a faculty-led community health clinical experience were analyzed. Students responded to pre- and posttravel semi-structured, open-ended prompts regarding expectations and perceptions of culture, health, and happiness. Data were analyzed using a qualitative descriptive approach. Four themes emerged related to perceptions of culture, relationships with community, definitions of health and happiness, and adaptability and innovation. African American students' (n = 3) responses highlighted unique themes regarding personal identity. Student perceptions of culture demonstrated progression through previously described stages of cultural competence. Relatively novel themes regarding community relationships, perceptions of health and happiness, and adaptability suggest additional value of this short-term study abroad experience for nursing students. [J Nurs Educ. 2017;56(9):528-533.]. Copyright 2017, SLACK Incorporated.

20 CFR 627.245 - Work experience.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Work experience. 627.245 Section 627.245... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.245 Work experience. (a) Definition. Work experience means a short-term or part-time training assignment with a public or private...

20 CFR 627.245 - Work experience.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Work experience. 627.245 Section 627.245... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.245 Work experience. (a) Definition. Work experience means a short-term or part-time training assignment with a public or private...

Fully automated multifunctional ultrahigh pressure liquid chromatography system for advanced proteome analyses

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

Lee, Jung Hwa; Hyung, Seok-Won; Mun, Dong-Gi

2012-08-03

A multi-functional liquid chromatography system that performs 1-dimensional, 2-dimensional (strong cation exchange/reverse phase liquid chromatography, or SCX/RPLC) separations, and online phosphopeptides enrichment using a single binary nano-flow pump has been developed. With a simple operation of a function selection valve, which is equipped with a SCX column and a TiO2 (titanium dioxide) column, a fully automated selection of three different experiment modes was achieved. Because the current system uses essentially the same solvent flow paths, the same trap column, and the same separation column for reverse-phase separation of 1D, 2D, and online phosphopeptides enrichment experiments, the elution time information obtainedmore » from these experiments is in excellent agreement, which facilitates correlating peptide information from different experiments.« less

Determining treatment requirements for turbid river water to avoid clogging of aquifer storage and recovery wells in siliceous alluvium.

PubMed

Page, Declan; Vanderzalm, Joanne; Miotliński, Konrad; Barry, Karen; Dillon, Peter; Lawrie, Ken; Brodie, Ross S

2014-12-01

The success of Aquifer Storage and Recovery (ASR) schemes relies on defining appropriate design and operational parameters in order to maintain high rates of recharge over the long term. The main contribution of this study was to define the water quality criteria and hence minimum pre-treatment requirements to allow sustained recharge at an acceptable rate in a medium-coarse sand aquifer. The source water was turbid, natural water from the River Darling, Australia. Three treatments were evaluated: bank filtration; coagulation and chlorine disinfection; and coagulation plus granular activated carbon and chlorine disinfection (GAC). Raw source water and the three treated waters were used in laboratory columns packed with aquifer material in replicate experiments in saturated conditions at constant temperature (19 °C) with light excluded for 37 days. Declines in hydraulic conductivity from a mean of 2.17 m/d occurred over the 37 days of the experiment. The GAC-treated water gave an 8% decline in hydraulic conductivity over the 16 cm length of columns, which was significantly different from the other three source waters, which had mean declines of 26-29%. Within the first 3 cm of column length, where most clogging occurred in each column, the mean hydraulic conductivity declined by 10% for GAC-treated water compared with 40-50% for the other source waters. There was very little difference between the columns until day 21, despite high turbidity (78 NTU) in the source water. Reducing turbidity by treatment was not sufficient to offset the reductions in hydraulic conductivity. Biological clogging was found to be most important as revealed by the accumulation of polysaccharides and bacterial numbers in columns when they were dissected and analysed at the end of the experiment. Further chemical clogging through precipitation of minerals was found not to occur within the laboratory columns, and dispersion of clay was also found to be negligible. Due to the low reduction in hydraulic conductivity, GAC-treated water quality was used to set pre-treatment targets for ASR injection of turbidity <0.6 NTU, membrane filtration index (MFI) < 2 s/L(2), biodegradable dissolved organic carbon (BDOC) < 0.2 mg/L, total nitrogen < 0.3 mg/L and residual chlorine > 0.2 mg/L. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Interplay between Short- and Long-Term Plasticity in Cell-Assembly Formation

PubMed Central

Hiratani, Naoki; Fukai, Tomoki

2014-01-01

Various hippocampal and neocortical synapses of mammalian brain show both short-term plasticity and long-term plasticity, which are considered to underlie learning and memory by the brain. According to Hebb’s postulate, synaptic plasticity encodes memory traces of past experiences into cell assemblies in cortical circuits. However, it remains unclear how the various forms of long-term and short-term synaptic plasticity cooperatively create and reorganize such cell assemblies. Here, we investigate the mechanism in which the three forms of synaptic plasticity known in cortical circuits, i.e., spike-timing-dependent plasticity (STDP), short-term depression (STD) and homeostatic plasticity, cooperatively generate, retain and reorganize cell assemblies in a recurrent neuronal network model. We show that multiple cell assemblies generated by external stimuli can survive noisy spontaneous network activity for an adequate range of the strength of STD. Furthermore, our model predicts that a symmetric temporal window of STDP, such as observed in dopaminergic modulations on hippocampal neurons, is crucial for the retention and integration of multiple cell assemblies. These results may have implications for the understanding of cortical memory processes. PMID:25007209

Transport Behavior of Functionalized Multi-Wall Carbon Nanotubes in Water-Saturated Quartz Sand as a Function of Tube Length

PubMed Central

Wang, Yonggang; Kim, Jae-Hong; Baek, Jong-Beom; Miller, Gary W.; Pennell, Kurt D.

2012-01-01

A series of one-dimensional column experiments was conducted to examine the effects of tube length on the transport and deposition of 4-ethoxybenzoic acid functionalized multi-wall carbon nanotubes (MWCNTs) in water-saturated porous media. Aqueous MWCNTs suspensions were prepared to yield three distributions of tube lengths; 0.02–1.3 μm (short), 0.2–7.5 μm (medium), and 0.2–21.4 μm (long). Results of the column studies showed that MWCNT retention increased with increasing tube length. Nevertheless, more than 76% of the MWCNT mass delivered to the columns was detected in effluent samples under all experimental conditions, indicating that the functionalized MWCNTs were readily transported through 40–50 mesh Ottawa sand. Examination of MWCNT length distributions in the effluent samples revealed that nanotubes with lengths greater than 8 μm were preferentially deposited. In addition, measured retention profiles exhibited the greatest MWCNT deposition near the column inlet, which was most pronounced for the long MWCNTs, and decreased sharply with travel distance. Scanning electron microscope (SEM) images showed that MWCNTs were deposited on sand surfaces over the entire column length, while larger MWCNT bundles were retained at grain intersections and near the column inlet. A mathematical model based on clean bed filtration theory (CBFT) was unable to accurately simulate the measured retention profile data, even after varying the weighting function and incorporating a nonuniform attachment rate coefficient expression. Modification of the mathematical model to account for physical straining greatly improved predictions of MWCNT retention, yielding straining rate coefficients that were four orders-of-magnitude greater than corresponding attachment rate coefficients. Taken in concert, these experimental and modeling results demonstrate the potential importance of, and need to consider, particle straining and tube length distribution when describing MWCNT transport in water-saturated porous media. PMID:22704927

Transport behavior of functionalized multi-wall carbon nanotubes in water-saturated quartz sand as a function of tube length.

PubMed

Wang, Yonggang; Kim, Jae-Hong; Baek, Jong-Beom; Miller, Gary W; Pennell, Kurt D

2012-09-15

A series of one-dimensional column experiments was conducted to examine the effects of tube length on the transport and deposition of 4-ethoxybenzoic acid functionalized multi-wall carbon nanotubes (MWCNTs) in water-saturated porous media. Aqueous MWCNTs suspensions were prepared to yield three distributions of tube lengths; 0.02-1.3 μm (short), 0.2-7.5 μm (medium), and 0.2-21.4 μm (long). Results of the column studies showed that MWCNT retention increased with increasing tube length. Nevertheless, more than 76% of the MWCNT mass delivered to the columns was detected in effluent samples under all experimental conditions, indicating that the functionalized MWCNTs were readily transported through 40-50 mesh Ottawa sand. Examination of MWCNT length distributions in the effluent samples revealed that nanotubes with lengths greater than 8 μm were preferentially deposited. In addition, measured retention profiles exhibited the greatest MWCNT deposition near the column inlet, which was most pronounced for the long MWCNTs, and decreased sharply with travel distance. Scanning electron microscope (SEM) images showed that MWCNTs were deposited on sand surfaces over the entire column length, while larger MWCNT bundles were retained at grain intersections and near the column inlet. A mathematical model based on clean bed filtration theory (CBFT) was unable to accurately simulate the measured retention profile data, even after varying the weighting function and incorporating a nonuniform attachment rate coefficient expression. Modification of the mathematical model to account for physical straining greatly improved predictions of MWCNT retention, yielding straining rate coefficients that were four orders-of-magnitude greater than corresponding attachment rate coefficients. Taken in concert, these experimental and modeling results demonstrate the potential importance of, and need to consider, particle straining and tube length distribution when describing MWCNT transport in water-saturated porous media. Copyright © 2012 Elsevier Ltd. All rights reserved.

5 CFR 412.401 - Continuing executive development.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Section 412.401 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS SUPERVISORY, MANAGEMENT, AND EXECUTIVE DEVELOPMENT Executive Development § 412.401 Continuing executive... participation in short-term and longer-term experiences, meet organizational needs for leadership, managerial...

5 CFR 412.401 - Continuing executive development.

Code of Federal Regulations, 2011 CFR

2011-01-01

... participation in short-term and longer-term experiences, meet organizational needs for leadership, managerial improvement, and organizational results; (2) Address enhancement of existing executive competencies and such other competencies as will strengthen the executive's performance; (3) Outline developmental...

Learning and the Spiral Illusion

ERIC Educational Resources Information Center

Houtman, S. D.

1974-01-01

The purpose of the experiment was to ascertain whether the duration of the spiral illusion could be extended by a 'learning procedure' which would distinguish a longer-term learning effect from short-term adaptive changes due to inhibition. (Author)

Similarity as an organising principle in short-term memory.

PubMed

LeCompte, D C; Watkins, M J

1993-03-01

The role of stimulus similarity as an organising principle in short-term memory was explored in a series of seven experiments. Each experiment involved the presentation of a short sequence of items that were drawn from two distinct physical classes and arranged such that item class changed after every second item. Following presentation, one item was re-presented as a probe for the 'target' item that had directly followed it in the sequence. Memory for the sequence was considered organised by class if probability of recall was higher when the probe and target were from the same class than when they were from different classes. Such organisation was found when one class was auditory and the other was visual (spoken vs. written words, and sounds vs. pictures). It was also found when both classes were auditory (words spoken in a male voice vs. words spoken in a female voice) and when both classes were visual (digits shown in one location vs. digits shown in another). It is concluded that short-term memory can be organised on the basis of sensory modality and on the basis of certain features within both the auditory and visual modalities.

Absence of center of mass control for leg abduction in long-term weightlessness in humans.

PubMed

Pedrocchi, Alessandra; Baroni, Guido; Mouchnino, Laurence; Ferrigno, Giancarlo; Pedotti, Antonio; Massion, Jean

2002-02-22

The present investigation describes for the first time leg lateral abduction performance during long-term microgravity exposure. Two astronauts took part in the experiments, starting 2 weeks into the mission and lasting for 5 months. Results on joint angles kinematics confirm previous investigations on parabolic flights, showing good task fulfillment for both subjects. Special interest was focused on whole body center of mass (CM) positioning. As in short-term microgravity, no initial CM lateral shift toward the 'supporting' leg was observed. In contrast with short-term microgravity and ground-based experiments, no stabilization of the CM medio-lateral position was found but a significant shift of CM toward the moving leg was observed. This suggests that the adaptation to sustained weightlessness might have led to a microgravity-specific motor strategy for leg abduction, which was not focused on CM strategy.

Impact of the column hardware volume on resolution in very high pressure liquid chromatography non-invasive investigations.

PubMed

Gritti, Fabrice; McDonald, Thomas; Gilar, Martin

2015-11-13

The impact of the column hardware volume (≃ 1.7 μL) on the optimum reduced plate heights of a series of short 2.1 mm × 50 mm columns (hold-up volume ≃ 80-90 μL) packed with 1.8 μm HSS-T3, 1.7 μm BEH-C18, 1.7 μm CSH-C18, 1.6 μm CORTECS-C18+, and 1.7 μm BEH-C4 particles was investigated. A rapid and non-invasive method based on the reduction of the system dispersion (to only 0.15 μL(2)) of an I-class Acquity system and on the corrected plate heights (for system dispersion) of five weakly retained n-alkanophenones in RPLC was proposed. Evidence for sample dispersion through the column hardware volume was also revealed from the experimental plot of the peak capacities for smooth linear gradients versus the corrected efficiency of a weakly retained alkanophenone (isocratic runs). The plot is built for a constant gradient steepness irrespective of the applied flow rates (0.01-0.30 mL/min) and column lengths (2, 3, 5, and 10 cm). The volume variance caused by column endfittings and frits was estimated in between 0.1 and 0.7 μL(2) depending on the applied flow rate. After correction for system and hardware dispersion, the minimum reduced plate heights of short (5 cm) and narrow-bore (2.1mm i.d.) beds packed with sub-2 μm fully and superficially porous particles were found close to 1.5 and 0.7, respectively, instead of the classical h values of 2.0 and 1.4 for the whole column assembly. Copyright © 2015 Elsevier B.V. All rights reserved.

Event-related brain potentials that distinguish false memory for events that occurred only seconds in the past.

PubMed

Chen, Hong; Voss, Joel L; Guo, Chunyan

2012-07-30

False memory often involves retrieving events from the distant past that did not actually happen. However, recent evidence obtained using the Deese/Roediger-McDermott (DRM) paradigm for eliciting false memory experiences suggests that individuals can falsely believe that events occurred mere seconds in the past when they in fact did not. Subjects in these experiments endorsed unstudied critical lure words as having been studied, despite the fact that word lists were studied just moments before. We identified event-related brain potential (ERP) correlates of this experience, and included a repetition priming manipulation to better assess the functional significance of these ERPs. Behavioral and ERP data were collected from 21 Capital Normal University students using a short-term DRM task. Two categories of effects were identified that distinguished true from false short-term memory: (1) early semantic priming effects from 300 to 500 ms and (2) later retrieval and retrieval-monitoring effects after 500 ms. The repetition priming manipulation had distinct influences on these effects, consistent with their differential associations with semantic priming versus episodic retrieval. Characterization of ERPs related to semantic priming and episodic retrieval provides important information regarding the mechanisms of short-term false memory. In contrast, most studies examining false memory in standard long-delay DRM paradigms identify ERP effects related only to retrieval monitoring. These findings highlight the neural processing involved in illusions of memory after very brief delays and highlight the role of semantic processing in short-term false memory.

Event-related brain potentials that distinguish false memory for events that occurred only seconds in the past

PubMed Central

2012-01-01

Background False memory often involves retrieving events from the distant past that did not actually happen. However, recent evidence obtained using the Deese/Roediger-McDermott (DRM) paradigm for eliciting false memory experiences suggests that individuals can falsely believe that events occurred mere seconds in the past when they in fact did not. Subjects in these experiments endorsed unstudied critical lure words as having been studied, despite the fact that word lists were studied just moments before. We identified event-related brain potential (ERP) correlates of this experience, and included a repetition priming manipulation to better assess the functional significance of these ERPs. Methods Behavioral and ERP data were collected from 21 Capital Normal University students using a short-term DRM task. Results Two categories of effects were identified that distinguished true from false short-term memory: (1) early semantic priming effects from 300 to 500 ms and (2) later retrieval and retrieval-monitoring effects after 500 ms. The repetition priming manipulation had distinct influences on these effects, consistent with their differential associations with semantic priming versus episodic retrieval. Conclusion Characterization of ERPs related to semantic priming and episodic retrieval provides important information regarding the mechanisms of short-term false memory. In contrast, most studies examining false memory in standard long-delay DRM paradigms identify ERP effects related only to retrieval monitoring. These findings highlight the neural processing involved in illusions of memory after very brief delays and highlight the role of semantic processing in short-term false memory. PMID:22846189

A Column Dispersion Experiment.

ERIC Educational Resources Information Center

Corapcioglu, M. Y.; Koroglu, F.

1982-01-01

Crushed glass and a Rhodamine B solution are used in a one-dimensional optically scanned column experiment to study the dispersion phenomenon in porous media. Results indicate that the described model gave satisfactory results and that the dispersion process in this experiment is basically convective. (DC)

Net community production and metabolic balance at the oligotrophic ocean site, station ALOHA

NASA Astrophysics Data System (ADS)

le B. Williams, Peter J.; Morris, Paul J.; Karl, David M.

2004-11-01

To test the hypothesis that in oligotrophic areas of the ocean respiration exceeds production, a 12-month study was undertaken of in vitro-determined net oxygen production and consumption in the top 150 m of the water column at the extreme oligotrophic site, Station ALOHA, in the North Pacific subtropical gyre. Throughout the year the water column was observed to be in metabolic deficit, the calculated cumulative shortfall being 9±1.7 mol O2 m-2 a-1 (approximately 100 g C m-2 a-1), an amount equivalent to 40% of measured production (annual estimated rates of production and consumption were, respectively, 22 and 31 mol O2 m-2 a-1). We consider three possible explanations for the observed deficit: the in vitro oxygen rate measurements, in themselves, are fundamentally flawed and should be discounted, the observations are correct and the observed deficit is a true account of the balance of oxygen (and organic carbon) at Station ALOHA, or the observations are correct as they stand, but need not be interpreted as organic carbon imbalance for that ecosystem. We find no error unique to the oxygen rate measurements themselves. We find also no evidence that the associated organic carbon deficit can be sustained over the long-term by internal organic reserves or by external subsidy. Accordingly we accept the geochemical findings that calculated in situ oxygen flux requires the euphotic zone of the water column at this site to be slightly (circa 2 mol C m-2 a-1) autotrophic, in contrast to the simple analysis of our observations which gives a net heterotrophic water column. We discuss a number of processes that may give rise to the observed discrepancy. In part it may derive from the difficulty of reproducing the variations in the light field experienced by an algal cell due to vertical advection. It may also derive from the intermittency of production. This latter effect would manifest itself in the following manner. Because of its universal distribution in the food web, respiration has greater integrating properties than photosynthesis and so will give a more accurate estimate of the long-term mean in studies with coarse sampling frequencies. If the system is undersampled, then short bursts of photosynthesis are prone to be missed from the integration of the production term but will be seen in the consumption term: hence the apparent deficit. The corollary of this line of reasoning is that, in undersampled systems, respiration has the potential to give a more accurate measurement of integrated system production than photosynthesis.

Preschoolers Continue to Trust a More Accurate Informant 1 Week after Exposure to Accuracy Information

ERIC Educational Resources Information Center

Corriveau, Kathleen; Harris, Paul L.

2009-01-01

To determine whether children retain a preference for a previously accurate informant only in the short term or for long-term use, 3- and 4-year-old children were tested in two experiments. In both experiments, children were given accuracy information about two informants and were subsequently tested for their selective trust in the two informants…

Separation of the Carotenoid Bixin from Annatto Seeds Using Thin-Layer and Column Chromatography

ERIC Educational Resources Information Center

McCullagh, James V.; Ramos, Nicholas

2008-01-01

In this experiment the carotenoid bixin is isolated from annatto ("Bixa orellana") seeds using column chromatography. The experiment has several key advantages over previous pigment separation experiments. First, unlike other experiments significant quantities of the carotenoid (typically 20 to 25 mg) can be isolated from small quantities of plant…

Effects of Irregular Bridge Columns and Feasibility of Seismic Regularity

NASA Astrophysics Data System (ADS)

Thomas, Abey E.

2018-05-01

Bridges with unequal column height is one of the main irregularities in bridge design particularly while negotiating steep valleys, making the bridges vulnerable to seismic action. The desirable behaviour of bridge columns towards seismic loading is that, they should perform in a regular fashion, i.e. the capacity of each column should be utilized evenly. But, this type of behaviour is often missing when the column heights are unequal along the length of the bridge, allowing short columns to bear the maximum lateral load. In the present study, the effects of unequal column height on the global seismic performance of bridges are studied using pushover analysis. Codes such as CalTrans (Engineering service center, earthquake engineering branch, 2013) and EC-8 (EN 1998-2: design of structures for earthquake resistance. Part 2: bridges, European Committee for Standardization, Brussels, 2005) suggests seismic regularity criterion for achieving regular seismic performance level at all the bridge columns. The feasibility of adopting these seismic regularity criterions along with those mentioned in literatures will be assessed for bridges designed as per the Indian Standards in the present study.

Long-term moderate wind induced sediment resuspension meeting phosphorus demand of phytoplankton in the large shallow eutrophic Lake Taihu.

PubMed

Chao, Jian-Ying; Zhang, Yi-Min; Kong, Ming; Zhuang, Wei; Wang, Long-Mian; Shao, Ke-Qiang; Gao, Guang

2017-01-01

The objective of this study was to investigate the impact of sediment resuspension and phosphorus (P) release on phytoplankton growth under different kinds of wind-wave disturbance conditions in the large and shallow eutrophic Lake Taihu in China. Short-term strong wind (STSW) conditions, long-term moderate wind (LTMW) conditions, and static/calm conditions were investigated. To address this objective, we (1) monitored changes in surface water P composition during field-based sediment resuspension caused by STSW conditions in Lake Taihu, and also conducted (2) a series of laboratory-based sediment resuspension experiments to simulate LTMW and calm conditions. The results showed that under both strong and moderate wind-wave conditions, suspended solids (SS) and total phosphorus (TP) in the water column increased significantly, but total dissolved phosphorus (TDP) and soluble reactive phosphorus (SRP) remained low throughout the experiments, indicating that the P released from sediments mainly existed in particulate forms. In STSW conditions, alkaline phosphatase activity (APA) and enzymatically hydrolysable phosphorus (EHP) increased rapidly, with the peak value occurring following the peak value of wind speed for 1-2 days, and then rapidly decreased after the wind stopped. Under LTMW conditions, APA and EHP increased steadily, and by the end of the laboratory experiments, APA increased by 11 times and EHP increased by 5 times. Chlorophyll a (Chl-a) in LTMW conditions increased significantly, but remained low under STSW conditions, demonstrating that the former type of sediment P release promoted phytoplankton growth more effectively, and the latter type did not. Despite the fact that STSW conditions resulted in the release of more TP, TP settled to the bottom rapidly with SS after the wind stopped, and did not promote algal growth. Under LTMW conditions, suspended particulate P was hydrolyzed to SRP by phosphatase and promoted algae growth. Algal growth in turn secreted more phosphatase and accelerated particulate P regeneration, which may be the main mechanism of sediment bio-available P release that promotes phytoplankton growth in shallow lakes.

Estimating phosphorus concentrations following alum treatment using apparent settling velocity

USGS Publications Warehouse

Panuska, John; Robertson, Dale M.

2009-01-01

he apparent settling velocity (Vs) is a term used in empirical, steady-state, mass-balance lake models to represent the net phosphorus flux from the water column. The Vollenweider (1969) mixed-reactor lake model was rearranged and used to calculate Vs values for total phosphorus (TP) for three lakes treated with alum to reduce the internal flux of P to the water column (Delavan Lake, Wisconsin; Lake Morey, Vermont; and West Twin Lake, Ohio). An analysis of Vs values was conducted using data from these three lakes for both the pre- and post-alum treated conditions. Analysis of Vs values for both the pre- and post-alum conditions in Lake Morey and West Twin Lake resulted in a post-treatment mean Vs value of 7 ± 2.0 m·yr−1. The effect of the alum treatment, although short-lived in Delavan Lake, resulted in a mean post-treatment Vs value of 3.4 ± 0.3 m·yr−1. The consistency in the post-treatment Vs values in Lake Morey and West Twin Lake is used to demonstrate a predictive analysis method for water column TP concentrations in lakes following a successful treatment of the anoxic sediment area with alum. Additional pre- and post-alum in-lake and watershed loading data are needed to advance this concept into a management model.

Study of the characteristics of reconfigurable plasma antenna array

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

Alias, Nur Salihah; Dagang, Ahmad Nazri; Ali, Mohd Tarmizi

This paper presents a design and simulation of a reconfigurable array of plasma antenna. The plasma column is used as radiating elements instead of metal to create an antenna. The advantages of the plasma antenna over the conventional antenna are its possible to change the operating parameters, such as the working pressure, input power, radius of the discharge tube, resonant frequency, and length of the plasma column. In addition, plasma antenna can be reconfigurable with respect to shape, frequency and radiation parameters in a very short time. The plasma discharge tube was designed with a length of 200 mm, the radiusmore » of the plasma column was 2.5 mm and the coupling sleeve was connected to the SMA as the ground. This simulation was performed by using the simulation software Computer Simulation Technology (CST). The frequency is set in the range of 1 GHz to 10 GHz. The performance of the designed antenna was analyzed in term of return loss, gain and radiation pattern. For reconfigurable plasma antenna array, it shows that the gain is increase when the number of antenna element is increase. The combination of the discharge tube and metal rod as an antenna array has been done, and the result shows that an array with the plasma element can achieve higher gain.« less

The effects of short-term and long-term learning on the responses of lateral intraparietal neurons to visually presented objects.

PubMed

Sigurdardottir, Heida M; Sheinberg, David L

2015-07-01

The lateral intraparietal area (LIP) is thought to play an important role in the guidance of where to look and pay attention. LIP can also respond selectively to differently shaped objects. We sought to understand to what extent short-term and long-term experience with visual orienting determines the responses of LIP to objects of different shapes. We taught monkeys to arbitrarily associate centrally presented objects of various shapes with orienting either toward or away from a preferred spatial location of a neuron. The training could last for less than a single day or for several months. We found that neural responses to objects are affected by such experience, but that the length of the learning period determines how this neural plasticity manifests. Short-term learning affects neural responses to objects, but these effects are only seen relatively late after visual onset; at this time, the responses to newly learned objects resemble those of familiar objects that share their meaning or arbitrary association. Long-term learning affects the earliest bottom-up responses to visual objects. These responses tend to be greater for objects that have been associated with looking toward, rather than away from, LIP neurons' preferred spatial locations. Responses to objects can nonetheless be distinct, although they have been similarly acted on in the past and will lead to the same orienting behavior in the future. Our results therefore indicate that a complete experience-driven override of LIP object responses may be difficult or impossible. We relate these results to behavioral work on visual attention.

Mini-Term: Exploring Career Choices

ERIC Educational Resources Information Center

Velcich, Joann; Mitchell, Mary Ellen

1976-01-01

Mini-term (an out-of-school, short-term, field experience) was implemented at the University of Knoxville so students could examine the work environment and job responsibilities of a specific career. Increase in student participation and positive student comments have provided the impetus for revising the program to meet future needs. (KRP)

Locus of Proactive Interference Effects in Short-Term Memory

ERIC Educational Resources Information Center

Dillon, Richard F.

1973-01-01

This article describes one experiment which tests a prediction from their explanation and another experiment which attempts to measure directly the amount of unlearning and spontaneous recovery-more generally, the availability-of competing responses. (Author)

Visual short-term memory for sequential arrays.

PubMed

Kumar, Arjun; Jiang, Yuhong

2005-04-01

The capacity of visual short-term memory (VSTM) for a single visual display has been investigated in past research, but VSTM for multiple sequential arrays has been explored only recently. In this study, we investigate the capacity of VSTM across two sequential arrays separated by a variable stimulus onset asynchrony (SOA). VSTM for spatial locations (Experiment 1), colors (Experiments 2-4), orientations (Experiments 3 and 4), and conjunction of color and orientation (Experiment 4) were tested, with the SOA across the two sequential arrays varying from 100 to 1,500 msec. We find that VSTM for the trailing array is much better than VSTM for the leading array, but when averaged across the two arrays VSTM has a constant capacity independent of the SOA. We suggest that multiple displays compete for retention in VSTM and that separating information into two temporally discrete groups does not enhance the overall capacity of VSTM.

Design and Operation of Cryogenic Distillation Research Column for Ultra-Low Background Experiments

NASA Astrophysics Data System (ADS)

Chiller, Christopher; Alanson Chiller, Angela; Jasinski, Benjamin; Snyder, Nathan; Mei, Dongming

2013-04-01

Motivated by isotopically enriched germanium (76Ge and 73Ge) for monocrystalline crystal growth for neutrinoless double-beta decay and dark matter experiments, a cryogenic distillation research column was developed. Without market availability of distillation columns in the temperature range of interest with capabilities necessary for our purposes, we designed, fabricated, tested, refined and operated a two-meter research column for purifying and separating gases in the temperature range from 100-200K. Due to interest in defining stratification, purity and throughput optimization, capillary lines were integrated at four equidistant points along the length of the column such that real-time residual gas analysis could guide the investigation. Interior gas column temperatures were monitored and controlled within 0.1oK accuracy at the top and bottom. Pressures were monitored at the top of the column to four significant figures. Subsequent impurities were measured at partial pressures below 2E-8torr. We report the performance of the column in this paper.

Atmospheric CO2 Column Measurements with an Airborne Intensity-Modulated Continuous-Wave 1.57-micron Fiber Laser Lidar

NASA Technical Reports Server (NTRS)

Dobler, Jeremy T.; Harrison, F. Wallace; Browell, Edward V.; Lin, Bing; McGregor, Doug; Kooi, Susan; Choi, Yonghoon; Ismail, Syed

2013-01-01

The 2007 National Research Council (NRC) Decadal Survey on Earth Science and Applications from Space recommended Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as a mid-term, Tier II, NASA space mission. ITT Exelis, formerly ITT Corp., and NASA Langley Research Center have been working together since 2004 to develop and demonstrate a prototype Laser Absorption Spectrometer for making high-precision, column CO2 mixing ratio measurements needed for the ASCENDS mission. This instrument, called the Multifunctional Fiber Laser Lidar (MFLL), operates in an intensity-modulated, continuous-wave mode in the 1.57- micron CO2 absorption band. Flight experiments have been conducted with the MFLL on a Lear-25, UC-12, and DC-8 aircraft over a variety of different surfaces and under a wide range of atmospheric conditions. Very high-precision CO2 column measurements resulting from high signal-to-noise (great than 1300) column optical depth measurements for a 10-s (approximately 1 km) averaging interval have been achieved. In situ measurements of atmospheric CO2 profiles were used to derive the expected CO2 column values, and when compared to the MFLL measurements over desert and vegetated surfaces, the MFLL measurements were found to agree with the in situ-derived CO2 columns to within an average of 0.17% or approximately 0.65 ppmv with a standard deviation of 0.44% or approximately 1.7 ppmv. Initial results demonstrating ranging capability using a swept modulation technique are also presented.

Observations of nonlinear and nonuniform kink dynamics in a laboratory flux rope

NASA Astrophysics Data System (ADS)

Sears, J.; Intrator, T.; Feng, Y.; Swan, H.; Gao, K.; Chapdelaine, L.

2013-12-01

A plasma column with axial magnetic field and current has helically twisted field lines. When current density in the column exceeds the kink instability threshold this magnetic configuration becomes unstable. Flux ropes in the solar wind and some solar prominences exhibit this topology, with their dynamics strongly and nonlinearly coupled to the ratio of axial current to magnetic field. The current-driven kink mode is ubiquitous in laboratory plasmas and well suited to laboratory study. In the Reconnection Scaling Experiment (RSX), nonlinear stability properties beyond the simple perturbative kink model are observed and readily diagnosed. We use a plasma gun to generate a single plasma column 0.50 m in length, in which we then drive an axial plasma current at the limit of marginal kink stability. With plasma current maintained at this threshold, we observe a deformation to a new dynamic equilibrium with finite gyration amplitude, where the currents and magnetic fields that support the force balance have surprising axial structure. Three dimensional measurements of magnetic field, plasma density, plasma potential, and ion flow velocity in the deformed plasma column show variation in the axial direction of the instability parameter and in the terms of the momentum equation. Likewise the pitch of the kink is measured to be nonuniform over the column length. In addition there is a return current antiparallel to the driven plasma current at distances up to 0.30 m from the gun that also modifies the force balance. These axial inhomogeneities, which are not considered in the model of an ideal kink, may be the terms that allow the deformed equilibrium of the RSX plasma to exist. Supported by DOE Office of Fusion Energy Sciences under LANS contract DE-AC52-06NA25369, NASA Geospace NNHIOA044I, Basic. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Developing Successful International Faculty Led Program

ERIC Educational Resources Information Center

Fabregas Janeiro, Maria G.; Fabre, Ricardo Lopez; Rosete, Rodrigo Tello

2012-01-01

Faculty Led Programs are study abroad experiences led by university professors. Faculty Led Programs are considered as an opportunity for college students, especially in the United States to attend a short-term international experience (Mills, 2010). Faculty Led Program is an international experience which is different from the traditional…

The effects of high energy particles on planetary missions

NASA Technical Reports Server (NTRS)

Robinson, Paul A., Jr.

1988-01-01

Researchers review the background and motivation for the detailed study of the variability and uncertainty of the particle environment from a space systems planning perspective. The engineering concern raised by each environment is emphasized rather than the underlying physics of the magnetosphere or the sun. Missions now being planned span the short term range of one to three years to periods over ten years. Thus the engineering interest is beginning to stretch over periods of several solar cycles. Coincidentally, detailed measurements of the environment are now becoming available over that period of time. Both short term and long term environmental predictions are needed for proper mission planning. Short term predictions, perhaps based on solar indices, real time observations, or short term systematics, are very useful in near term planning -- launches, EVAs (extravehicular activities), coordinated observations, and experiments which require the magnetosphere to be in a certain state. Long term predictions of both average and extreme conditions are essential to mission design. Engineering considerations are many times driven by the worst case environment. Knowledge of the average conditions and their variability allows trade-off studies to be made, implementation of designs which degrade gracefully under multi-stress environments.

Escaping the recent past: Which stimulus dimensions influence proactive interference?

PubMed Central

Craig, Kimberly S.; Berman, Marc G.; Jonides, John; Lustig, Cindy

2013-01-01

Proactive interference occurs when information from the past disrupts current processing and is a major source of confusion and errors in short-term memory (Wickens, Born & Allen, 1963). The present investigation examines potential boundary conditions for interference, testing the hypothesis that potential competitors must be similar along task-relevant dimensions to influence proactive interference effects. We manipulated both the type of task being completed (Experiments 1, 2 and 3) and dimensions of similarity irrelevant to the current task (Experiments 4 and 5) to determine how the recent presentation of a probe item would affect the speed with which participants could reject that item. Experiments 1, 2 and 3 contrasted short-term memory judgments, which require temporal information, with semantic and perceptual judgments, for which temporal information is irrelevant. In Experiments 4 and 5, task-irrelevant information (perceptual similarity) was manipulated within the recent probes task. We found that interference from past items affected short-term memory (STM) task performance but did not affect performance in semantic or perceptual judgment tasks. Conversely, similarity along a nominally-irrelevant perceptual dimension did not affect the magnitude of interference in STM tasks. Results are consistent with the view that items in STM are represented by noisy codes consisting of multiple dimensions, and that interference occurs when items are similar to each other and thus compete along the dimensions relevant to target selection. PMID:23297049

Patterns in Temporal Variability of Temperature, Oxygen and pH along an Environmental Gradient in a Coral Reef

PubMed Central

Guadayol, Òscar; Silbiger, Nyssa J.; Donahue, Megan J.; Thomas, Florence I. M.

2014-01-01

Spatial and temporal environmental variability are important drivers of ecological processes at all scales. As new tools allow the in situ exploration of individual responses to fluctuations, ecologically meaningful ways of characterizing environmental variability at organism scales are needed. We investigated the fine-scale spatial heterogeneity of high-frequency temporal variability in temperature, dissolved oxygen concentration, and pH experienced by benthic organisms in a shallow coastal coral reef. We used a spatio-temporal sampling design, consisting of 21 short-term time-series located along a reef flat-to-reef slope transect, coupled to a long-term station monitoring water column changes. Spectral analyses revealed sharp gradients in variance decomposed by frequency, as well as differences between physically-driven and biologically-reactive parameters. These results highlight the importance of environmental variance at organismal scales and present a new sampling scheme for exploring this variability in situ. PMID:24416364

Post-project appraisals in adaptive management of river channel restoration.

PubMed

Downs, Peter W; Kondolf, G Mathias

2002-04-01

Post-project appraisals (PPAs) can evaluate river restoration schemes in relation to their compliance with design, their short-term performance attainment, and their longer-term geomorphological compatibility with the catchment hydrology and sediment transport processes. PPAs provide the basis for communicating the results of one restoration scheme to another, thereby improving future restoration designs. They also supply essential performance feedback needed for adaptive management, in which management actions are treated as experiments. PPAs allow river restoration success to be defined both in terms of the scheme attaining its performance objectives and in providing a significant learning experience. Different levels of investment in PPA, in terms of pre-project data and follow-up information, bring with them different degrees of understanding and tbus different abilities to gauge both types of success. We present four case studies to illustrate how the commitment to PPA has determined the understanding achieved in each case. In Moore's Gulch (California, USA), understanding was severely constrained by the lack of pre-project data and post-implementation monitoring. Pre-project data existed for the Kitswell Brook (Hertfordshire, UK), but the monitoring consisted only of one site visit and thus the understanding achieved is related primarily to design compliance issues. The monitoring undertaken for Deep Run (Maryland, USA) and the River Idle (Nottinghamshire, UK) enabled some understanding of the short-term performance of each scheme. The transferable understanding gained from each case study is used to develop an illustrative five-fold classification of geomorphological PPAs (full, medium-term, short-term, one-shot, and remains) according to their potential as learning experiences. The learning experience is central to adaptive management but rarely articulated in the literature. Here, we gauge the potential via superimposition onto a previous schematic representation of the adaptive management process by Haney and Power (1996). Using PPAs wisely can lead to cutting-edge, complex solutions to river restoration challenges.

Improving UK Air Quality Modelling Through Exploitation of Satellite Observations

NASA Astrophysics Data System (ADS)

Pope, Richard; Chipperfield, Martyn; Savage, Nick

2014-05-01

In this work the applicability of satellite observations to evaluate the operational UK Met Office Air Quality in the Unified Model (AQUM) have been investigated. The main focus involved the AQUM validation against satellite observations, investigation of satellite retrieval error types and of synoptic meteorological-atmospheric chemistry relationships simulated/seen by the AQUM/satellite. The AQUM is a short range forecast model of atmospheric chemistry and aerosols up to 5 days. It has been designed to predict potentially hazardous air pollution events, e.g. high concentrations of surface ozone. The AQUM has only been validated against UK atmospheric chemistry recording surface stations. Therefore, satellite observations of atmospheric chemistry have been used to further validate the model, taking advantage of better satellite spatial coverage. Observations of summer and winter 2006 tropospheric column NO2 from both OMI and SCIAMACHY show that the AQUM generally compares well with the observations. However, in northern England positive biases (AQUM - satellite) suggest that the AQUM overestimates column NO2; we present results of sensitivity experiments on UK emissions datasets suspected to be the cause. In winter, the AQUM over predicts background column NO2 when compared to both satellite instruments. We hypothesise that the cause is the AQUM winter night-time chemistry, where the NO2 sinks are not substantially defined. Satellite data are prone to errors/uncertainty such as random, systematic and smoothing errors. We have investigated these error types and developed an algorithm to calculate and reduce the random error component of DOAS NO2 retrievals, giving more robust seasonal satellite composites. The Lamb Weather Types (LWT), an objective method of classifying the daily synoptic weather over the UK, were used to create composite satellite maps of column NO2 under different synoptic conditions. Under cyclonic conditions, satellite observed UK column NO2 is reduced as the indicative south-westerly flow transports it away from the UK over the North Sea. However, under anticyclonic conditions, the satellite shows that the stable conditions enhance the build-up of column NO2 over source regions. The influence of wind direction on column NO2 can also be seen from space with transport leeward of the source regions.

Gradient stationary phase optimized selectivity liquid chromatography with conventional columns.

PubMed

Chen, Kai; Lynen, Frédéric; Szucs, Roman; Hanna-Brown, Melissa; Sandra, Pat

2013-05-21

Stationary phase optimized selectivity liquid chromatography (SOSLC) is a promising technique to optimize the selectivity of a given separation. By combination of different stationary phases, SOSLC offers excellent possibilities for method development under both isocratic and gradient conditions. The so far available commercial SOSLC protocol utilizes dedicated column cartridges and corresponding cartridge holders to build up the combined column of different stationary phases. The present work is aimed at developing and extending the gradient SOSLC approach towards coupling conventional columns. Generic tubing was used to connect short commercially available LC columns. Fast and base-line separation of a mixture of 12 compounds containing phenones, benzoic acids and hydroxybenzoates under both isocratic and linear gradient conditions was selected to demonstrate the potential of SOSLC. The influence of the connecting tubing on the deviation of predictions is also discussed.

Isotopic generator for bismuth-212 and lead-212 based on radium

DOEpatents

Hines, J.J.; Atcher, R.W.; Friedman, A.M.

1985-01-30

Disclosed are method and apparatus for providing radionuclides of bismuth-212 and lead-212. Thorium-228 and carrier solution starting material is input to a radiologically contained portion of an isotopic generator system, and radium-224 is separated from thorium-228 which is retained by a strongly basic anion exchange column. The separated radium-224 is transferred to an accessible, strongly acidic cationic exchange column. The cationic column retains the radium-224, and natural radioactive decay generates bismuth-212 and lead-212. The cationic exchange column can also be separated from the contained portion of the system and utilized without the extraordinary safety measures necessary in the contained portion. Furthermore, the cationic exchange column provides over a relatively long time period the short lived lead-212 and bismuth-212 radionuclides which are useful for a variety of medical therapies.

Isotopic generator for bismuth-212 and lead-212 from radium

DOEpatents

Atcher, Robert W.; Friedman, Arnold M.; Hines, John

1987-01-01

A method and apparatus for providing radionuclides of bismuth-212 and lead-212. Thorium-228 and carrier solution starting material is input to a radiologically contained portion of an isotopic generator system, and radium-224 is separated from thorium-228 which is retained by a strongly basic anion exchange column. The separated radium-224 is transferred to an accessible, strongly acidic cationic exchange column. The cationic column retains the radium-224, and natural radioactive decay generates bismuth-212 and lead-212. The cationic exchange column can also be separated from the contained portion of the system and utilized without the extraordinary safety measures necessary in the contained portion. Furthermore, the cationic exchange column provides over a relatively long time period the short lived lead-212 and bismuth-212 radionuclides which are useful for a variety of medical therapies.

A practical guide for short-term pediatric surgery global volunteers.

PubMed

Meier, Donald E; Fitzgerald, Tamara N; Axt, Jason R

2016-08-01

The tremendous need for increasing the quantity and quality of global pediatric surgical care in underserved areas has been well documented. Concomitantly there has been a significant increase in interest by pediatric surgeons in helping to relieve this problem through surgical volunteerism. The intent of the article is to serve as a practical guide for pediatric surgeons contemplating or planning a short-term global volunteer endeavor. The article is based on the authors' personal experiences and on the published experiences of other volunteers. The following aspects of volunteerism are discussed: ethical considerations, where and how to go, what and whom to take with you, what to expect in your volunteer locale, and what to do and what to avoid in order to enhance the volunteer experience. The points discussed in this guide will hopefully make the volunteer activity one that results in greatly improved immediate and long term surgical care for children and improves the chances that the activity will be a meaningful, pleasant, and productive experience for both the volunteer and the host physician. Copyright © 2016 Elsevier Inc. All rights reserved.

The index gage method to develop a flow duration curve from short-term streamflow records

NASA Astrophysics Data System (ADS)

Zhang, Zhenxing

2017-10-01

The flow duration curve (FDC) is one of the most commonly used graphical tools in hydrology and provides a comprehensive graphical view of streamflow variability at a particular site. For a gaged site, an FDC can be easily estimated with frequency analysis. When no streamflow records are available, regional FDCs are used to synthesize FDCs. However, studies on how to develop FDCs for sites with short-term records have been very limited. Deriving representative FDC when there are short-term hydrologic records is important. For instance, 43% of the 394 streamflow gages in Illinois have records of 20 years or fewer, and these short-term gages are often distributed in headwaters and contain valuable hydrologic information. In this study, the index gage method is proposed to develop FDCs using short-term hydrologic records via an information transfer technique from a nearby hydrologically similar index gage. There are three steps: (1) select an index gage; (2) determine changes of FDC; and (3) develop representative FDCs. The approach is tested using records from 92 U.S. Geological Survey streamflow gages in Illinois. A jackknife experiment is conducted to assess the performance. Bootstrap resampling is used to simulate various periods of records, i.e., 1, 2, 5, 10, 15, and 20 years of records. The results demonstrated that the index gage method is capable of developing a representative FDC using short-term records. Generally, the approach performance is improved when more hydrologic records are available, but the improvement appears to level off when the short-term gage has 10 years or more records.

Attentional control constrains visual short-term memory: Insights from developmental and individual differences

PubMed Central

Astle, D.E.; Nobre, A.C.; Scerif, G.

2014-01-01

The mechanisms by which attentional control biases mnemonic representations have attracted much interest but remain poorly understood. As attention and memory develop gradually over childhood and variably across individuals, assessing how participants of different ages and ability attend to mnemonic contents can elucidate their interplay. In Experiment 1, 7-, 10-year-olds and adults were asked to report whether a probe item had been part of a previously presented four-item array. The initial array could either be uncued, preceded (“pre-cued”) or followed (“retro-cued”) by a spatial cue orienting attention to one of the potential item locations. Performance across groups was significantly improved by both cue types and individual differences in children’s retrospective attentional control predicted their visual short-term and working memory span, whereas their basic ability to remember in the absence of cues did not. Experiment 2 imposed a variable delay between the array and the subsequent orienting cue. Cueing benefits were greater in adults compared to 10-year-olds, but they persisted even when cues followed the array by nearly 3 seconds, suggesting that orienting operated on durable short-term representations for both age groups. The findings indicate that there are substantial developmental and individual differences in the ability to control attention to memory and that in turn these differences constrain visual short-term memory capacity. PMID:20680889

Attentional control constrains visual short-term memory: insights from developmental and individual differences.

PubMed

Astle, Duncan E; Nobre, Anna C; Scerif, Gaia

2012-01-01

The mechanisms by which attentional control biases mnemonic representations have attracted much interest but remain poorly understood. As attention and memory develop gradually over childhood and variably across individuals, assessing how participants of different ages and ability attend to mnemonic contents can elucidate their interplay. In Experiment 1, 7-year-olds, 10-year-olds, and adults were asked to report whether a probe item had been part of a previously presented four-item array. The initial array could either be uncued, be preceded ("precued"), or followed ("retrocued") by a spatial cue orienting attention to one of the potential item locations. Performance across groups was significantly improved by both cue types, and individual differences in children's retrospective attentional control predicted their visual short-term and working memory span, whereas their basic ability to remember in the absence of cues did not. Experiment 2 imposed a variable delay between the array and the subsequent orienting cue. Cueing benefits were greater in adults than in 10-year-olds, but they persisted even when cues followed the array by nearly 3 seconds, suggesting that orienting operated on durable short-term representations for both age groups. The findings indicate that there are substantial developmental and individual differences in the ability to control attention to memory and that in turn these differences constrain visual short-term memory capacity.

Short-term incorporation of organic manures and biofertilizers influences biochemical and microbial characteristics of soils under an annual crop [Turmeric (Curcuma longa L.)].

PubMed

Dinesh, R; Srinivasan, V; Hamza, S; Manjusha, A

2010-06-01

The study was conducted to determine whether short-term incorporation of organic manures and biofertilizers influence biochemical and microbial variables reflecting soil quality. For the study, soils were collected from a field experiment conducted on turmeric (Curcuma longa L.) involving organic nutrient management (ONM), chemical nutrient management (CNM) and integrated nutrient management (INM). The findings revealed that application of organic manures and biofertilizers (ONM and INM) positively influenced microbial biomass C, N mineralization, soil respiration and enzymes activities. Contrarily, greater metabolic quotient levels in CNM indicated a stressed soil microbial community. Principal component analysis indicated the strong relationship between microbial activity and the availability of labile and easily mineralizable organic matter. The findings imply that even short-term incorporation of organic manures and biofertilizers promoted soil microbial and enzyme activities and these parameters are sensitive enough to detect changes in soil quality due to short-term incorporation of biological fertilizers. (c) 2010 Elsevier Ltd. All rights reserved.

Robust short-term memory without synaptic learning.

PubMed

Johnson, Samuel; Marro, J; Torres, Joaquín J

2013-01-01

Short-term memory in the brain cannot in general be explained the way long-term memory can--as a gradual modification of synaptic weights--since it takes place too quickly. Theories based on some form of cellular bistability, however, do not seem able to account for the fact that noisy neurons can collectively store information in a robust manner. We show how a sufficiently clustered network of simple model neurons can be instantly induced into metastable states capable of retaining information for a short time (a few seconds). The mechanism is robust to different network topologies and kinds of neural model. This could constitute a viable means available to the brain for sensory and/or short-term memory with no need of synaptic learning. Relevant phenomena described by neurobiology and psychology, such as local synchronization of synaptic inputs and power-law statistics of forgetting avalanches, emerge naturally from this mechanism, and we suggest possible experiments to test its viability in more biological settings.

Comparative study on short- and long-term behavioral consequences of organophosphate exposure: relationship to AChE mRNA expression.

PubMed

López-Granero, Caridad; Cardona, Diana; Giménez, Estela; Lozano, Rafael; Barril, José; Aschner, Michael; Sánchez-Santed, Fernando; Cañadas, Fernando

2014-01-01

Organophosphates (OPs) affect behavior by inhibiting acetylcholinesterase (AChE). While the cognitive short-term effects may be directly attributed to this inhibition, the mechanisms that underlie OP's long-term cognitive effects remain controversial and poorly understood. Accordingly, two experiments were designed to assess the effects of OPs on cognition, and to ascertain whether both the short- and long-term effects of are AChE-dependent. A single subcutaneous dose of 250 mg/kg chlorpyrifos (CPF), 1.5mg/kg diisopropylphosphorofluoridate (DFP) or 15 mg/kg parathion (PTN) was administered to male Wistar rats. Spatial learning was evaluated 72 h or 23 weeks after exposure, and impulsive choice was tested at 10 and 30 weeks following OPs administration (experiment 1 and 2, respectively). Brain soluble and membrane-bound AChE activity, synaptic AChE-S mRNA, read-through AChE-R mRNA and brain acylpeptide hydrolase (APH) activity (as alternative non-cholinergic target) were analyzed upon completion of the behavioral testing (17 and 37 weeks after OPs exposure). Both short- and long-term CPF treatment caused statistically significant effects on spatial learning, while PTN treatment led only to statistically significant short-term effects. Neither CPF, DFP nor PTN affected the long-term impulsivity response. Long-term exposure to CPF and DFP significantly decreased AChE-S and AChE-R mRNA, while in the PTN treated group only AChE-S mRNA levels were decreased. However, after long-term OP exposure, soluble and membrane-bound AChE activity was indistinguishable from controls. Finally, no changes were noted in brain APH activity in response to OP treatment. Taken together, this study demonstrates long-term effects of OPs on AChE-S and AChE-R mRNA in the absence of changes in AChE soluble and membrane-bound activity. Thus, changes in AChE mRNA expression imply non-catalytic properties of the AChE enzyme. Copyright © 2013 Elsevier Inc. All rights reserved.

Hydrodynamic flow in capillary-channel fiber columns for liquid chromatography.

PubMed

Stanelle, Rayman D; Sander, Lane C; Marcus, R Kenneth

2005-12-23

The flow characteristics of capillary-channel polymer (C-CP) fiber liquid chromatographic (LC) columns have been investigated. The C-CP fibers are manufactured with eight longitudinal grooves (capillary channels) extending the length of the fibers. Three C-CP fiber examples were studied, with fiber dimensions ranging from approximately 35 microm to 65 microm, and capillary-channel dimensions ranging from approximately 6 microm to 35 microm. The influence of fiber packing density and column inner diameter on peak asymmetry, peak width, and run-to-run reproducibility have been studied for stainless steel LC columns packed with polyester (PET) and polypropylene (PP) C-CP fibers. The van Deemter A-term was evaluated as a function of fiber packing density (approximately 0.3 g/cm(3)-0.75 g/cm(3)) for columns of 4.6 mm inner diameter (i.d.) and at constant packing densities for 1.5 mm, 3.2 mm, 4.6 mm, and 7.7 mm i.d. columns. Although column diameter had little influence on the eluting peak widths, peak asymmetry increased with increasing column diameter. The A-terms for the C-CP fiber packed columns are somewhat larger than current commercial, microparticulate-packed columns, and means for improvement are discussed. Applications in the area of protein (macromolecule) separations appear the most promising at this stage of the system development.

Chemical factors influencing colloid-facilitated transport of contaminants in porous media

USGS Publications Warehouse

Roy, Sujoy B.; Dzombak, David A.

1997-01-01

The effects of colloids on the transport of two strongly sorbing solutesa hydrophobic organic compound, phenanthrene, and a metal ion, Ni2+were studied in sand-packed laboratory columns under different pH and ionic strength conditions. Two types of column experiments were performed as follows:  (i) sorption/mobilization experiments where the contaminant was first sorbed in the column under conditions where no colloids were released and mobilized under conditions where colloids were released as a result of ionic strength reduction in the influent; and (ii) transport experiments where the contaminant, dissolved or sorbed on colloids, was injected into columns packed with a strongly sorbing porous medium. In the first type of experiment, contaminant mobilization was significant only when all releasable colloids were flushed from the column. In all other cases, although high colloid particle concentrations were encountered, there was no marked effect on total contaminant concentrations. In the second type of experiment, colloid deposition efficiencies were shown to control the enhancement of transport. The deposition efficiency was a function of the pH (for a high organic content sand) and of the contaminant concentration (for a charged species such as Ni2+).

Episodic Short-Term Recognition Requires Encoding into Visual Working Memory: Evidence from Probe Recognition after Letter Report

PubMed Central

Poth, Christian H.; Schneider, Werner X.

2016-01-01

Human vision is organized in discrete processing episodes (e.g., eye fixations or task-steps). Object information must be transmitted across episodes to enable episodic short-term recognition: recognizing whether a current object has been seen in a previous episode. We ask whether episodic short-term recognition presupposes that objects have been encoded into capacity-limited visual working memory (VWM), which retains visual information for report. Alternatively, it could rely on the activation of visual features or categories that occurs before encoding into VWM. We assessed the dependence of episodic short-term recognition on VWM by a new paradigm combining letter report and probe recognition. Participants viewed displays of 10 letters and reported as many as possible after a retention interval (whole report). Next, participants viewed a probe letter and indicated whether it had been one of the 10 letters (probe recognition). In Experiment 1, probe recognition was more accurate for letters that had been encoded into VWM (reported letters) compared with non-encoded letters (non-reported letters). Interestingly, those letters that participants reported in their whole report had been near to one another within the letter displays. This suggests that the encoding into VWM proceeded in a spatially clustered manner. In Experiment 2, participants reported only one of 10 letters (partial report) and probes either referred to this letter, to letters that had been near to it, or far from it. Probe recognition was more accurate for near than for far letters, although none of these letters had to be reported. These findings indicate that episodic short-term recognition is constrained to a small number of simultaneously presented objects that have been encoded into VWM. PMID:27713722

Episodic Short-Term Recognition Requires Encoding into Visual Working Memory: Evidence from Probe Recognition after Letter Report.

PubMed

Poth, Christian H; Schneider, Werner X

2016-01-01

Human vision is organized in discrete processing episodes (e.g., eye fixations or task-steps). Object information must be transmitted across episodes to enable episodic short-term recognition: recognizing whether a current object has been seen in a previous episode. We ask whether episodic short-term recognition presupposes that objects have been encoded into capacity-limited visual working memory (VWM), which retains visual information for report. Alternatively, it could rely on the activation of visual features or categories that occurs before encoding into VWM. We assessed the dependence of episodic short-term recognition on VWM by a new paradigm combining letter report and probe recognition. Participants viewed displays of 10 letters and reported as many as possible after a retention interval (whole report). Next, participants viewed a probe letter and indicated whether it had been one of the 10 letters (probe recognition). In Experiment 1, probe recognition was more accurate for letters that had been encoded into VWM (reported letters) compared with non-encoded letters (non-reported letters). Interestingly, those letters that participants reported in their whole report had been near to one another within the letter displays. This suggests that the encoding into VWM proceeded in a spatially clustered manner. In Experiment 2, participants reported only one of 10 letters (partial report) and probes either referred to this letter, to letters that had been near to it, or far from it. Probe recognition was more accurate for near than for far letters, although none of these letters had to be reported. These findings indicate that episodic short-term recognition is constrained to a small number of simultaneously presented objects that have been encoded into VWM.

An ethics curriculum for short-term global health trainees.

PubMed

DeCamp, Matthew; Rodriguez, Joce; Hecht, Shelby; Barry, Michele; Sugarman, Jeremy

2013-02-14

Interest in short-term global health training and service programs continues to grow, yet they can be associated with a variety of ethical issues for which trainees or others with limited global health experience may not be prepared to address. Therefore, there is a clear need for educational interventions concerning these ethical issues. We developed and evaluated an introductory curriculum, "Ethical Challenges in Short-term Global Health Training." The curriculum was developed through solicitation of actual ethical issues experienced by trainees and program leaders; content drafting; and external content review. It was then evaluated from November 1, 2011, through July 1, 2012, by analyzing web usage data and by conducting user surveys. The survey included basic demographic data; prior experience in global health and global health ethics; and assessment of cases within the curriculum. The ten case curriculum is freely available at http://ethicsandglobalhealth.org. An average of 238 unique visitors accessed the site each month (standard deviation, 19). Of users who had been abroad before for global health training or service, only 31% reported prior ethics training related to short-term work. Most users (62%) reported accessing the site via personal referral or their training program; however, a significant number (28%) reported finding the site via web search, and 8% discovered it via web links. Users represented different fields: medicine (46%), public health (15%), and nursing (11%) were most common. All cases in the curriculum were evaluated favorably. The curriculum is meeting a critical need for an introduction to the ethical issues in short-term global health training. Future work will integrate this curriculum within more comprehensive curricula for global health and evaluate specific knowledge and behavioral effects, including at training sites abroad.

An ethics curriculum for short-term global health trainees

PubMed Central

2013-01-01

Background Interest in short-term global health training and service programs continues to grow, yet they can be associated with a variety of ethical issues for which trainees or others with limited global health experience may not be prepared to address. Therefore, there is a clear need for educational interventions concerning these ethical issues. Methods We developed and evaluated an introductory curriculum, “Ethical Challenges in Short-term Global Health Training.” The curriculum was developed through solicitation of actual ethical issues experienced by trainees and program leaders; content drafting; and external content review. It was then evaluated from November 1, 2011, through July 1, 2012, by analyzing web usage data and by conducting user surveys. The survey included basic demographic data; prior experience in global health and global health ethics; and assessment of cases within the curriculum. Results The ten case curriculum is freely available at http://ethicsandglobalhealth.org. An average of 238 unique visitors accessed the site each month (standard deviation, 19). Of users who had been abroad before for global health training or service, only 31% reported prior ethics training related to short-term work. Most users (62%) reported accessing the site via personal referral or their training program; however, a significant number (28%) reported finding the site via web search, and 8% discovered it via web links. Users represented different fields: medicine (46%), public health (15%), and nursing (11%) were most common. All cases in the curriculum were evaluated favorably. Conclusions The curriculum is meeting a critical need for an introduction to the ethical issues in short-term global health training. Future work will integrate this curriculum within more comprehensive curricula for global health and evaluate specific knowledge and behavioral effects, including at training sites abroad. PMID:23410089

Reliability assessment of ceramic column grid array (CCGA717) interconnect packages under extreme temperatures for space applications (-185°C to +125°C)

NASA Astrophysics Data System (ADS)

Ramesham, Rajeshuni

2010-02-01

Ceramic Column Grid Array packages have been increasing in use based on their advantages such as high interconnect density, very good thermal and electrical performance, compatibility with standard surface-mount packaging assembly processes, etc. CCGA packages are used in space applications such as in logics and microprocessor functions, telecommunications, flight avionics, payload electronics, etc. As these packages tend to have less solder joint strain relief than leaded packages, the reliability of CCGA packages is very important for short and long-term space missions. CCGA interconnect electronic package printed wiring boards (PWBs) of polyimide have been assembled, inspected non-destructively and subsequently subjected to extreme temperature thermal cycling to assess the reliability for future deep space, short and long-term, extreme temperature missions. In this investigation, the employed temperature range covers from -185°C to +125°C extreme thermal environments. The test hardware consists of two CCGA717 packages with each package divided into four daisy-chained sections, for a total of eight daisy chains to be monitored. The CCGA717 package is 33 mm × 33 mm with a 27×27 array of 80%/20% Pb/Sn columns on a 1.27 mm pitch. The resistance of daisy-chained, CCGA interconnects were continuously monitored as a function of thermal cycling. Electrical resistance measurements as a function of thermal cycling are reported and the tests to date have shown significant change in daisy chain resistance as a function of thermal cycling. The change in interconnect resistance becomes more noticeable with increasing number of thermal cycles. This paper will describe the experimental test results of CCGA testing under wide extreme temperatures. Standard Weibull analysis tools were used to extract the Weibull parameters to understand the CCGA failures. Optical inspection results clearly indicate that the solder joints of columns with the board and the ceramic package have failed as a function of thermal cycling. The first failure was observed at 137th thermal cycle and 63.2% failures of daisy chains have occurred at about 664 thermal cycles. The shape parameter extracted from Weibull plot was about 1.47 which indicates the failures were related to failures occurred during the flat region or useful life region of standard bath tub curve. Based on this experimental test data one can use the CCGAs for the temperature range studied for ~100 thermal cycles (ΔT = 310°C, 5oC/minute, and 15 minutes dwell) with high degree of confidence for high reliability space and other applications.

Determination of thermodynamic and transport parameters of naphthenic acids and organic process chemicals in oil sand tailings pond water.

PubMed

Wang, Xiaomeng; Robinson, Lisa; Wen, Qing; Kasperski, Kim L

2013-07-01

Oil sand tailings pond water contains naphthenic acids and process chemicals (e.g., alkyl sulphates, quaternary ammonium compounds, and alkylphenol ethoxylates). These chemicals are toxic and can seep through the foundation of the tailings pond to the subsurface, potentially affecting the quality of groundwater. As a result, it is important to measure the thermodynamic and transport parameters of these chemicals in order to study the transport behavior of contaminants through the foundation as well as underground. In this study, batch adsorption studies and column experiments were performed. It was found that the transport parameters of these chemicals are related to their molecular structures and other properties. The computer program (CXTFIT) was used to further evaluate the transport process in the column experiments. The results from this study show that the transport of naphthenic acids in a glass column is an equilibrium process while the transport of process chemicals seems to be a non-equilibrium process. At the end of this paper we present a real-world case study in which the transport of the contaminants through the foundation of an external tailings pond is calculated using the lab-measured data. The results show that long-term groundwater monitoring of contaminant transport at the oil sand mining site may be necessary to avoid chemicals from reaching any nearby receptors.

TNT transport and fate in contaminated soil

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

Comfort, S.D.; Shea, P.J.; Hundal, L.S.

1995-11-01

Past disposal practices at munitions production plants have contaminated terrestrial and aquatk ecosystems with 2,4,6-trinitrotoluene (TNT). We determined TNT transport, degradation, and long-term sorption characteristics in soil. Transport experiments were conducted with repacked, unsaturated soil columns containing uncontaminated soil or layers of contaminated and uncontaminated soil. Uncontaminated soil columns received multiple pore volumes (22-50) of a TNT-{sup 3}H{sub 2}O pulse, containing 70 or 6.3 mg TNT L{sup -1} at a constant pore water velocity. TNT breakthrough curves (BTCs) never reached initial solute pulse concentrations. Apex concentrations (C/C{sub o}) were between 0.6 and 0.8 for an initial pulse of 70 mgmore » TNT L{sup -1} and 0.2 to 0.3 for the 6.3 mg TNT L{sup -1} pulse. Earlier TNT breakthrough was observed at the higher pulse concentration. This mobility difference was predicted from the nonlinear adsorption isotherm determined for TNT sorption. In all experiments, a significant fraction of added TNT was recovered as amino degradates of TNT. Mass balance estimates indicated 81% of the added TNT was recovered (as TNT and amino degradates) from columns receiving the 70 mg TNT L{sup -1} pulse compared to 35% from columns receiving the 6.3 mg TNT L{sup -1} pulse. Most of the unaccountable TNT was hypothesized to be unextractable. This was supported by a 168-d sorption experiment, which found that within 14d, 80% of {sup 14}C activity (added as {sup 14}C-TNT) was adsorbed and roughly 40% unextractable. Our observations illustrate that TNT sorption and degradation are concentration-dependent and the assumptions of linear adsorption and adsorption-desorption singularity commonly used in transport modeling, may not be valid for predicting TNT transport in munitions-contaminated soils. 29 refs., 6 figs., 7 tabs.« less

Short-term training in geriatrics: an alternative for family medicine?

PubMed

Vernon, M S; Worthington, R C

1992-01-01

Family medicine has responded to the need for training in geriatrics by creating geriatric fellowships and by including geriatric education in residency and medical school curricula. Fellowships, in particular, require extensive time commitment by participating physicians. We developed a 1-month geriatric training experience for academic family physicians. We surveyed previous participants in this short course to determine their subsequent level of activity in geriatrics, whether they had become certified in geriatrics, and other information about their academic experience in geriatrics. Eighty-one percent of graduates of this 1-month course had passed the geriatrics certification examination, compared to only 56% nationally. Graduates of the program were active as geriatric program directors and teachers of geriatrics, but there was limited activity in research or other scholarly activities related to geriatrics. Intensive short-term training in geriatrics meets some but not all of the needs for academic competency and productivity in geriatrics.

Primary productivity by phytoplankton in the tidal, fresh Potomac River, Maryland, May 1980 to August 1981

USGS Publications Warehouse

Cohen, R.R.; Pollock, S.O.

1983-01-01

Primary productivity by phytoplankton was measured on samples collected from the Potomac Tidal River, Maryland. The studies were performed monthly from May 1980 to September 1981. Additional studies were done once a week in August 1980, twice a week from August 4 to 8, 1980 and twice in September 1980. Depth-integrated samples were collected at five stations and incubated in boxes that were exposed to natural sunlight. The boxes were covered with neutral density filters transmitting 100 , 65, 32, 16, and 6 percent surface light. River water was pumped continuously over the samples. The extinction of light in the water column by phytoplankton was measured when samples were collected. Experiments were performed to select a method for routine productivity analysis. No difference was found between productivity: (1) determined in situ and in boxes; (2) measured in 300 ml and (4) calculated from short term (4 hours) and long term (10-24 hours) incubations. There were higher productivity differences in samples that were rotated among different light intensities every 15 minutes (simulating mixing) than those remaining stationary. Respiration was significantly less in samples pumped through a hose from those collected using a depth-integrating sampler. Depth-integrated primary productivity was determined from the productivity data using an equation modified from one reported in the literature. Depth-integrated gross primary productivity was highest in August 1980 and 1981 and lowest in January 1980. (USGS)

MODELING MERCURY DYNAMICS IN STREAM SYSTEMS WITH WASP7: CHARACTERIZING PROCESSES CONTROLLING SHORT AND LONG TERM RESPONSE

EPA Science Inventory

Mercury transport through stream ecosystems is driven by a complicated set of transport and transformation reactions operating on a variety of scales in the atmosphere, landscape, surface water, and biota. Riverine systems typically have short residence times and can experience l...

Natural Medicine: Wilderness Experience Outcomes for Combat Veterans

ERIC Educational Resources Information Center

Dietrich, Zachary Clayborne; Joye, Shauna Wilson; Garcia, Joseph Amos

2015-01-01

Wilderness Experience Programs (WEPs) have been shown to enhance psychological well-being for numerous populations. However, among veteran populations, these studies have historically evaluated programs that are short-term experiences, usually less than 1 week. The current research sought to evaluate a WEP for post-9/11 combat veterans engaging in…

Adapting to the destitute situations: poverty cues lead to short-term choice.

PubMed

Liu, Lei; Feng, Tingyong; Suo, Tao; Lee, Kang; Li, Hong

2012-01-01

Why do some people live for the present, whereas others save for the future? The evolutionary framework of life history theory predicts that preference for delay of gratification should be influenced by social economic status (SES). However, here we propose that the decision to choose alternatives in immediate and delayed gratification in poverty environments may have a psychological dimension. Specifically, the perception of environmental poverty cues may induce people alike to favor choices with short-term, likely smaller benefit than choices with long-term, greater benefit. The present study was conducted to explore how poverty and affluence cues affected individuals' intertemporal choices. In our first two experiments, individuals exposed explicitly (Experiment 1) and implicitly (Experiment 2) to poverty pictures (the poverty cue) were induced to prefer immediate gratification compared with those exposed to affluence pictures (the affluence cue). Furthermore, by the manipulation of temporary perceptions of poverty and affluence status using a lucky draw game; individuals in the poverty state were more impulsive in a manner, which made them pursue immediate gratification in intertemporal choices (Experiment 3). Thus, poverty cues can lead to short-term choices. Decision makers chose more frequently the sooner-smaller reward over the later-larger reward as they were exposed to the poverty cue. This indicates that it is that just the feeling of poverty influences intertemporal choice - the actual reality of poverty (restricted resources, etc.) is not necessary to get the effect. Furthermore, our findings emphasize that it is a change of the poverty-affluence status, not a trait change, can influence individual preference in intertemporal choice.

Sequential Injection Chromatography with an Ultra-short Monolithic Column for the Low-Pressure Separation of α-Tocopherol and γ-Oryzanol in Vegetable Oils and Nutrition Supplements.

PubMed

Thaithet, Sujitra; Kradtap Hartwell, Supaporn; Lapanantnoppakhun, Somchai

2017-01-01

A low-pressure separation procedure of α-tocopherol and γ-oryzanol was developed based on a sequential injection chromatography (SIC) system coupled with an ultra-short (5 mm) C-18 monolithic column, as a lower cost and more compact alternative to the HPLC system. A green sample preparation, dilution with a small amount of hexane followed by liquid-liquid extraction with 80% ethanol, was proposed. Very good separation resolution (R s = 3.26), a satisfactory separation time (10 min) and a total run time including column equilibration (16 min) were achieved. The linear working range was found to be 0.4 - 40 μg with R 2 being more than 0.99. The detection limits of both analytes were 0.28 μg with the repeatability within 5% RSD (n = 7). Quantitative analyses of the two analytes in vegetable oil and nutrition supplement samples, using the proposed SIC method, agree well with the results from HPLC.

Why do participants initiate free recall of short lists of words with the first list item? Toward a general episodic memory explanation.

PubMed

Spurgeon, Jessica; Ward, Geoff; Matthews, William J

2014-11-01

Participants who are presented with a short list of words for immediate free recall (IFR) show a strong tendency to initiate their recall with the 1st list item and then proceed in forward serial order. We report 2 experiments that examined whether this tendency was underpinned by a short-term memory store, of the type that is argued by some to underpin recency effects in IFR. In Experiment 1, we presented 3 groups of participants with lists of between 2 and 12 words for IFR, delayed free recall, and continuous-distractor free recall. The to-be-remembered words were simultaneously spoken and presented visually, and the distractor task involved silently solving a series of self-paced, visually presented mathematical equations (e.g., 3 + 2 + 4 = ?). The tendency to initiate recall at the start of short lists was greatest in IFR but was also present in the 2 other recall conditions. This finding was replicated in Experiment 2, where the to-be-remembered items were presented visually in silence and the participants spoke aloud their answers to computer-paced mathematical equations. Our results necessitate that a short-term buffer cannot be fully responsible for the tendency to initiate recall from the beginning of a short list; rather, they suggest that the tendency represents a general property of episodic memory that occurs across a range of time scales. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Serial reconstruction of order and serial recall in verbal short-term memory.

PubMed

Quinlan, Philip T; Roodenrys, Steven; Miller, Leonie M

2017-10-01

We carried out a series of experiments on verbal short-term memory for lists of words. In the first experiment, participants were tested via immediate serial recall, and word frequency and list set size were manipulated. With closed lists, the same set of items was repeatedly sampled, and with open lists, no item was presented more than once. In serial recall, effects of word frequency and set size were found. When a serial reconstruction-of-order task was used, in a second experiment, robust effects of word frequency emerged, but set size failed to show an effect. The effects of word frequency in order reconstruction were further examined in two final experiments. The data from these experiments revealed that the effects of word frequency are robust and apparently are not exclusively indicative of output processes. In light of these findings, we propose a multiple-mechanisms account in which word frequency can influence both retrieval and preretrieval processes.

Electrophysiological correlates of the maintenance of the representation of pitch objects in acoustic short-term memory.

PubMed

Guimond, Synthia; Vachon, François; Nolden, Sophie; Lefebvre, Christine; Grimault, Stephan; Jolicoeur, Pierre

2011-11-01

We studied the neuronal mechanisms that implement acoustic short-term memory (ASTM) for pitch using event-related potentials (ERP). Experiment 1 isolated an ERP component, the sustained anterior negativity (SAN), that increased in amplitude with increasing memory load in ASTM using stimuli with equal duration at all memory loads. The SAN load effect found in Experiment 1, when pitch had to be remembered to perform the task, was absent in Experiment 2 using the same sounds when memory was not required. In Experiment 3, the memory task was performed without or with concurrent articulatory suppression during the retention interval to prevent rehearsal via an articulatory loop. Load-related effects observed in Experiment 1 were found again, whether participants engaged in concurrent suppression or not. The results suggest that the SAN reflects activity required to maintain pitch objects in an ASTM system that is distinct from articulatory rehearsal. Copyright © 2011 Society for Psychophysiological Research.

Short-term and long-term effects of guar on postprandial plasma glucose, insulin and glucagon-like peptide 1 concentration in healthy rats.

PubMed

Prieto, P G; Cancelas, J; Villanueva-Peñacarrillo, M L; Malaisse, W J; Valverde, I

2006-06-01

Ingestion of guar gum decreases postprandial glycemia and insulinemia and improves sensitivity to insulin in diabetic patients and several animal models of diabetes. The aim of the present study was to compare the short-term and long-term effects of guar on plasma insulin and glucagon-like peptide 1 concentration in healthy rats. In the short-term experiments, the concomitant intragastric administration of glucose and guar reduced the early increment in plasma glucose, insulin and glucagon-like peptide 1 concentration otherwise induced by glucose alone. Comparable findings were made after twelve days of meal training exposing the rats to either a control or guar-enriched diet for fifteen minutes. Mean plasma glucose concentrations were lower while mean insulin concentrations were higher in the guar group than in the controls according to intragastric glucose tolerance tests conducted in overnight fasted rats maintained for 19 to 36 days on either the control or guar-enriched diet. The intestinal content of glucagon-like peptide 1 at the end of the experiments was also lower in the guar group. Changes in body weight over 62 days of observation were comparable in the control and guar rats. Thus, long-term intake of guar improves glucose tolerance and insulin response to glucose absorption, without improving insulin sensitivity, in healthy rats.

Commander prepares glass columns for electrophoresis experiment

NASA Technical Reports Server (NTRS)

1982-01-01

Commander Jack Lousma prepares on of the glass columns for the electrophoresis test in the middeck area of the Columbia. The experiment, deployed in an L-shaped mode in upper right corner, consists of the processing unit with glass columns in which the separation takes place; a camera (partially obscurred by Lousma's face) to document the process; and a cryogenic freezer to freeze and store the samples after separation.

Nondestructive evaluation of the preservation state of stone columns in the Hospital Real of Granada

NASA Astrophysics Data System (ADS)

Moreno de Jong van Coevorden, C.; Cobos Sánchez, C.; Rubio Bretones, A.; Fernández Pantoja, M.; García, Salvador G.; Gómez Martín, R.

2012-12-01

This paper describes the results of the employment of two nondestructive evaluation methods for the diagnostic of the preservation state of stone elements. The first method is based on ultrasonic (US) pulses while the second method uses short electromagnetic pulses. Specifically, these methods were applied to some columns, some of them previously restored. These columns are part of the architectonic heritage of the University of Granada, in particular they are located at the patio de la capilla del Hospital Real of Granada. The objective of this work was the application of systems based on US pulses (in transmission mode) and the ground-penetrating radar systems (electromagnetic tomography) in the diagnosis and detection of possible faults in the interior of columns.

Vapour-Phase Processes Control Liquid-Phase Isotope Profiles in Unsaturated Sphagnum Moss

NASA Astrophysics Data System (ADS)

Edwards, T. W.; Yi, Y.; Price, J. S.; Whittington, P. N.

2009-05-01

Seminal work in the early 1980s clearly established the basis for predicting patterns of heavy-isotope enrichment of pore waters in soils undergoing evaporation. A key feature of the process under steady-state conditions is the development of stable, convex-upward profiles whose shape is controlled by the balance between downward-diffusing heavy isotopologues concentrated by evaporative enrichment at the surface and the upward capillary flow of bulk water that maintains the evaporative flux. We conducted an analogous experiment to probe evaporation processes within 20-cm columns of unsaturated, living and dead (but undecomposed) Sphagnum moss evaporating under controlled conditions, while maintaining a constant water table. The experiment provided striking evidence of the importance of vapour-liquid mass and isotope exchange in the air-filled pores of the Sphagnum columns, as evidenced by the rapid development of hydrologic and isotopic steady-state within hours, rather than days, i.e., an order of magnitude faster than possible by liquid-phase processes alone. This is consistent with the notion that vapour-phase processes effectively "short-circuit" mass and isotope fluxes within the Sphagnum columns, as proposed also in recent characterizations of water dynamics in transpiring leaves. Additionally, advection-diffusion modelling of our results supports independent estimates of the effective liquid-phase diffusivities of the respective heavy water isotopologues, 2.380 x 10-5 cm2 s-1 for 1H1H18O and 2.415 x 10-5 cm2 s-1 for 1H2H16O, which are in notably good agreement with the "default" values that are typically assumed in soil and plant water studies.

Comparison of the effects of dose-dependent zinc chloride on short-term and long-term memory in young male rats.

PubMed

Moazedi, A A; Ghotbeddin, Z; Parham, G H

2007-08-15

The aim of the present study was to evaluate the effects of dose-dependent of zinc chloride on short-term and long-term memory in a shuttle box. Young Wistar rats (94+/-10 g) (age 27-30 days) consumed zinc chloride drinking water in five different doses (20, 30, 50, 70 and 100 mg kg(-1) day(-1)) for two weeks by gavage. After 14 days on experimental diets, a shuttle box used to test short- and long-term memory. Two criteria considering for behavioral test, including latency in entering dark chamber and time spent in the dark chamber. This experiment shows that after 2 weeks oral administration of ZnCl2 with (20, 30 and 50 mg kg(-1) day(-1)) doses, the rat's working (short-term) has been improved (p<0.05). Whereas ZnCl2 with 30 mg kg(-1) day(-1) dose has been more effected than other doses (p<0.001). But rat which received ZnCl2 with 100 mg kg(-1) day(-1), has been shown significant impairment in working memory (p<0.05) and there was no significant difference in reference (long-term) memory for any of groups. In general, this study has demonstrated that zinc chloride consumption with 30 mg kg(-1) day(-1) dose for two weeks was more effective than other doses on short-term memory. But consumption of ZnCl2 with 100 mg kg(-1) day(-1) dose for two week had the negative effect on short-term memory. On the other hand, zinc supplementation did not have an effect on long-term memory.

Retention of Content Utilizing a Flipped Classroom Approach.

PubMed

Shatto, Bobbi; LʼEcuyer, Kristine; Quinn, Jerod

The flipped classroom experience promotes retention and accountability for learning. The authors report their evaluation of a flipped classroom for accelerated second-degree nursing students during their primary medical-surgical nursing course. Standardized HESI® scores were compared between a group of students who experienced the flipped classroom and a previous group who had traditional teaching methods. Short- and long-term retention was measured using standardized exams 3 months and 12 months following the course. Results indicated that short-term retention was greater and long- term retention was significantly great in the students who were taught using flipped classroom methodology.

Short-term and long-term outcomes of laparoscopic hepatectomy, microwave ablation, and open hepatectomy for small hepatocellular carcinoma: a 5-year experience in a single center.

PubMed

Li, Wenda; Zhou, Xue; Huang, Zejian; Zhang, Kelin; Luo, Xuan; Zhong, Jinyi; Chen, Yajin

2017-06-01

Laparoscopic hepatectomy (LH), microwave ablation (MWA), and open hepatectomy (OH) are three widely used methods to treat small hepatocellular carcinoma (HCC). However, few studies have compared the short- and long-term outcomes of these three treatments. The aim of this study was to investigate their effectiveness. The data were reviewed from 280 patients with HCCs measuring ≤3 cm (Barcelona Clinic Liver Cancer stage 0 or A) who received LH (n = 133), OH (n = 87), or MWA (n = 60) in our research center from 2005 to 2010. Short-term outcomes included intraoperative blood loss, operation time, and length of hospital stay. The disease-free survival and overall survival rates were analyzed as long-term outcomes. The patients in the MWA and LH groups showed better short-term outcomes compared with those in the OH group. There were no significant differences in overall survival rates among the three treatments. The LH group showed significantly lower recurrence rates than the MWA group (P = 0.0146). Laparoscopic hepatectomy may be a better option for patients with small HCC located on the liver surface and left lateral lobe. The short-term outcome of MWA is promising, although the high risk of local recurrence after the operation should be considered when planning treatment. © 2016 The Japan Society of Hepatology.

Storing information in-the-world: Metacognition and cognitive offloading in a short-term memory task.

PubMed

Risko, Evan F; Dunn, Timothy L

2015-11-01

We often store to-be-remembered information externally (e.g., written down on a piece of paper) rather than internally. In the present investigation, we examine factors that influence the decision to store information in-the-world versus in-the-head using a variant of a traditional short term memory task. In Experiments 1a and 1b participants were presented with to-be-remembered items and either had to rely solely on internal memory or had the option to write down the presented information. In Experiments 2a and 2b participants were presented with the same stimuli but made metacognitive judgments about their predicted performance and effort expenditure. The spontaneous use of external storage was related both to the number of items to be remembered and an individual's actual and perceived short-term-memory capacity. Interestingly, individuals often used external storage despite its use affording no observable benefit. Implications for understanding how individuals integrate external resources in pursuing cognitive goals are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

PubMed

Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

2017-12-08

In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

The Price of Fame: The Impact of Stimulus Familiarity on Proactive Interference Resolution

PubMed Central

Prabhakaran, Ranjani; Thompson-Schill, Sharon L.

2013-01-01

Interference from previously learned information, known as proactive interference (PI), limits our memory retrieval abilities. Previous studies of PI resolution have focused on the role of short-term familiarity, or recency, in causing PI. In the present study, we investigated the impact of long-term stimulus familiarity on PI resolution processes. In two behavioral experiments and one event-related fMRI experiment, long-term familiarity was manipulated through the use of famous and nonfamous stimuli, and short-term familiarity was manipulated through the use of recent and nonrecent probe items in an item recognition task. The right middle frontal gyrus demonstrated greater sensitivity to famous stimuli, suggesting that long-term stimulus familiarity plays a role in influencing PI resolution processes. Further examination of the effect of long-term stimulus familiarity on PI resolution revealed a larger behavioral interference effect for famous stimuli, but only under speeded response conditions. Thus, models of memory retrieval—and of the cognitive control mechanisms that guide retrieval processes—should consider the impact of and interactions among sources of familiarity on multiple time scales. PMID:20429858

The price of fame: the impact of stimulus familiarity on proactive interference resolution.

PubMed

Prabhakaran, Ranjani; Thompson-Schill, Sharon L

2011-04-01

Interference from previously learned information, known as proactive interference (PI), limits our memory retrieval abilities. Previous studies of PI resolution have focused on the role of short-term familiarity, or recency, in causing PI. In the present study, we investigated the impact of long-term stimulus familiarity on PI resolution processes. In two behavioral experiments and one event-related fMRI experiment, long-term familiarity was manipulated through the use of famous and nonfamous stimuli, and short-term familiarity was manipulated through the use of recent and nonrecent probe items in an item recognition task. The right middle frontal gyrus demonstrated greater sensitivity to famous stimuli, suggesting that long-term stimulus familiarity plays a role in influencing PI resolution processes. Further examination of the effect of long-term stimulus familiarity on PI resolution revealed a larger behavioral interference effect for famous stimuli, but only under speeded response conditions. Thus, models of memory retrieval--and of the cognitive control mechanisms that guide retrieval processes--should consider the impact of and interactions among sources of familiarity on multiple time scales.

Column strength of tubes elastically restrained against rotation at the ends

NASA Technical Reports Server (NTRS)

Osgood, William R

1938-01-01

Report presents the results of a study made of the effects of known end restraint on commercially available round and streamline tubing of chromium-molybdenum steel, duralumin, stainless steel, and heat-treated chromium-molybdenum steel; and a more accurate method than any previously available, but still a practical method, was developed for designing compression members in riveted or welded structures, particularly aircraft. Two hundred specimens were tested as short, medium-length, and long columns with freely supported ends or elastically restrained ends. Tensile and compressive tests were made on each piece of original tubing from which column specimens were cut.

A Platform for Simulating Language Evolution

NASA Astrophysics Data System (ADS)

Vogel, Carl; Woods, Justin

A platform for conducting experiments in the simulation of natural language evolution is presented. The system is paramaterized for independent specification of important features like: number of agents, communication attempt frequency, agent short term memory capacity, communicative urgency, etc. Representative experiments are demonstrated.

Column experiments on organic micropollutants - applications and limitations

NASA Astrophysics Data System (ADS)

Banzhaf, Stefan; Hebig, Klaus

2016-04-01

As organic micropollutants become more and more ubiquitous in the aquatic environment, a sound understanding of their fate and transport behaviour is needed. This is to assure both safe and clean drinking water supply for mankind in the future and to protect the aquatic environment from pollution and negative consequences caused by manmade contamination. Apart from countless field studies, column experiments were and are frequently used to study transport of organic micropollutants. As the transport of (organic) solutes in groundwater is controlled by the chemical and physical properties of the compounds, the solvent (the groundwater including all solutes), and the substrate (the aquifer material), the adjustment and control of these boundary conditions allow to study a multitude of different experimental setups and to address specific research questions. The main purpose, however, remains to study the transport of a specific compound and its sorption and degradation behaviour in a specific sediment or substrate. Apart from the effective control of the individual boundary conditions, the main advantage of columns studies compared to other experimental setups (such as field studies, batch/microcosm studies), is that conservative and reactive solute breakthrough curves are obtained, which represent the sum of the transport processes. The analysis of these curves is well-developed and established. Additionally, limitations of this experimental method are presented here: the effects observed in column studies are often a result of dynamic, non-equilibrium processes. Time (or flow velocity) plays a major role in contrast to batch experiments, in which all processes will be observed until equilibrium is reached in the substrate-solution-system. Slightly modifying boundary conditions in different experiments have a strong influence on transport and degradation behaviour of organic micropollutants. This is a significant severe issue when it comes to general findings on the transport behaviour of a specific organic compound that are transferable to any given hydrogeochemical environment. Unfortunately, results of most column experiments therefore remain restricted to their specific setup. Column experiments can provide good estimates of all relevant transport parameters. However, the obtained results will almost always be limited to the scale they were obtained from. This means that direct application to field scale studies is infeasible as too many parameters are exclusive for the laboratory column setup. The remaining future challenge is to develop standard column experiments on organic micropollutants that overcome this issue. Here, we present a review of column experiments on organic micropollutants. We present different setups and discuss weaknesses, problems and advantages and provide ideas how to obtain more comparable results on the transport of organic micropollutants in the future.

Impact of material heterogeneity on solute transport behavior in the unsaturated zone of the Calcaire de Beauce aquifer (France)

NASA Astrophysics Data System (ADS)

Viel, Emelie; Coquet, Yves

2016-04-01

Since a few decades, the Calcaire de Beauce aquifer is contaminated with nitrate. The nitrate dynamics in the aquifer and in the surface soil are quite well understood, but its transport through the vadose zone remains largely unknown. When models fail to simulate nitrate concentrations in wells, preferential flow or physical non-equilibrium transport in soil and in the vadose zone is usually put forward to explain this failure. To study transport processes in the vadose zone of the Calcaire de Beauce aquifer, undisturbed cores (30 cm length and 20 cm diameter) have been taken below the deepest soil horizon. At the field scale, the vadose zone is composed of powdery limestone spatially very heterogeneous, and including a variable amount of coarse elements. Two columns were selected: column "6" is made of very fine homogeneous limestone whereas column "8" is very heterogeneous with a large proportion of coarse elements. Elution experiments have been performed on both columns. A tracer (Br- or DFBA) in a solution of 5 mM CaCl2 was spread as a pulse on the top of the column with a rainfall simulator. Input flow rate was kept constant for steady state cases, or suddenly closed for flux interruption cases. Outflow was collected as a function of time for tracer concentration measurement. The collected fractions were analyzed by HPLC (High-performance liquid chromatography) with a UV detector. Three types of experiments took place: • For steady state experiments, three rainfall rates, respectively 4, 8, and 16 mm/h, have been used to study the occurrence of immobile water in the columns. The tracer was injected during 120 min followed by CaCl2 tracer-free solution at same flow rate. • For flux-interruption experiments, only the 4 and 8 mm/h rainfall rates were used. The tracer was injected during 120 min, input and output fluxes were then stopped and restarted seven days later with the same flow rate. • For drainage experiments, only the 4 and 8 mm/h rainfall rates were used as well. The tracer was injected during 120 min, input flux was stopped while output flux continued to occur under the -25 cm matric head bottom boundary condition. Flux restarted seven days later with the same flow rate or another flow rate. STANMOD was used for each BTC to estimate transport parameters assuming steady state flux. The standard CDE was suitable for column 6 steady-state experiments, but the MIM had to be used to describe properly the BTCs of column 8. In this column, the immobile water fraction represented 38 %. Flux interruption experiments showed that the form of the BTC for Column 6 was not disturbed for the 4 and 8 mm/h input flux, whereas the form of BTC for Column 8 had significantly changed with a visible steeper increase after an interruption time compared to the corresponding steady state experiment. This difference of behavior could be related to the difference in limestone material. The immobile water fraction was found to be significant only for columns made of heterogeneous limestone.

Tunnel frit: a nonmetallic in-capillary frit for nanoflow ultra high-performance liquid chromatography-mass spectrometryapplications.

PubMed

Chen, Chao-Jung; Chen, Wei-Yun; Tseng, Mei-Chun; Chen, Yet-Ran

2012-01-03

In this study, an easy method to fabricate a durable in-capillary frit was developed for use in nanoflow liquid chromatography (nanoLC). A small orifice was tunneled into the sol-gel frit during the polymerization process resulting in the simple fabrication of a tunnel frit. A short packing tunnel frit column (2 cm, C(18) particles) was able to sustain over 10,000 psi continuous liquid flow for 10 days without observation of particle loss, and back pressure variation was less than 5%. The tunnel frit was successfully applied to the fabrication of nanoflow ultra high-performance liquid chromatography (nano-UHPLC) trap and analytical columns. In the analysis of tryptic peptides, the tunnel frit trap and analytical columns were demonstrated to have high separation efficiency and sensitivity. In analysis of phosphopeptides, the use of the nonmetallic tunnel frit column showed better sensitivity than the metallic frit column. This design can facilitate the preparation of nano-HPLC and nano-UHPLC columns and the packing material can easily be refilled when the column is severely contaminated or clogged. © 2011 American Chemical Society

Sustainable materials used as stone column filler: A short review

NASA Astrophysics Data System (ADS)

Zukri, Azhani; Nazir, Ramli

2018-04-01

Stone columns (also known as granular piles) are one of the methods for soft soil stabilization and typically used to increase bearing capacity and stability of slope.; Apart from decreasing the compressibility of loose and fine graded soils, it also accelerates the consolidation effect by improving the drainage path for pore water pressure dissipation and reduces the liquefaction potential of soils during earthquake event. Stone columns are probably the most “natural” ground treatment method or foundation system in existence to date. The benefit of stone columns is owing to the partial replacement of compressible soil by more competent materials such as stone aggregate, sand and other granular materials. These substitutes also act as reinforcement material, hence increasing overall strength and stiffness of the soft soil. Nowadays, a number of research has been conducted on the behaviour and performance of stone columns with various materials utilized as column filler replacing the normal aggregate. This paper will review extensively on previously conducted research on some of the materials used as stone column backfill materials, its suitability and the effectiveness as a substitute for regular aggregates in soft soil improvement works.

Competitive adsorption and selectivity sequence of heavy metals by chicken bone-derived biochar: Batch and column experiment.

PubMed

Park, Jong-Hwan; Cho, Ju-Sik; Ok, Yong Sik; Kim, Seong-Heon; Kang, Se-Won; Choi, Ik-Won; Heo, Jong-Soo; DeLaune, Ronald D; Seo, Dong-Cheol

2015-01-01

The objective of this research was to evaluate adsorption of heavy metals in single- and ternary-metal forms onto chicken bone biochar (CBB). Competitive sorption of heavy metals by CBB has never been reported previously. The maximum adsorption capacities of metals by CBB were in the order of Cu (130 mg g(-1)) > Cd (109 mg g(-1)) > Zn (93 mg g(-1)) in the single-metal adsorption isotherm and Cu (108 mg g(-1)) > Cd (54 mg g(-1)) ≥ Zn (44 mg g(-1)) in the ternary-metal adsorption isotherm. Cu was the most retained cation, whereas Zn could be easily exchanged and substituted by Cu. Batch experimental data best fit the Langmuir model rather than the Freundlich isotherms. In the column experiments, the total adsorbed amounts of the metals were in the following order of Cu (210 mg g(-1)) > Cd (192 mg g(-1)) > Zn (178) in single-metal conditions, and Cu (156) > Cd (123) > Zn (92) in ternary-metal conditions. Results from both the batch and column experiments indicate that competitive adsorption among metals increases the mobility of these metals. Especially, Zn in single-metal conditions lost it adsorption capacity most significantly. Based on the 3D simulation graphs of heavy metals, adsorption patterns under single adsorption condition were different than under competitive adsorption condition. Results from both the batch and column experiments show that competitive adsorption among metals increases the mobility of these metals. The maximum metal adsorption capacity of the metals in the column experiments was higher than that in the batch experiment indicating other metal retention mechanisms rather than adsorption may be involved. Therefore, both column and batch experiments are needed for estimating retention capacities and removal efficiencies of metals in CBB.

Effects of Cabin Upsets on Adsorption Columns for Air Revitalization

NASA Technical Reports Server (NTRS)

LeVan, M. Douglas

1999-01-01

The National Aeronautics and Space Administration (NASA) utilizes adsorption technology as part of contaminant removal systems designed for long term missions. A variety of trace contaminants can be effectively removed from gas streams by adsorption onto activated carbon. An activated carbon adsorption column meets NASA's requirements of a lightweight and efficient means of controlling trace contaminant levels aboard spacecraft and space stations. The activated carbon bed is part of the Trace Contaminant Control System (TCCS) which is utilized to purify the cabin atmosphere. TCCS designs oversize the adsorption columns to account for irregular fluctuations in cabin atmospheric conditions. Variations in the cabin atmosphere include changes in contaminant concentrations, temperature, and relative humidity. Excessively large deviations from typical conditions can result from unusual crew activity, equipment malfunctions, or even fires. The research carried out under this award focussed in detail on the effects of cabin upsets on the performance of activated carbon adsorption columns. Both experiments and modeling were performed with an emphasis on the roll of a change in relative humidity on adsorption of trace contaminants. A flow through fixed-bed apparatus was constructed at the NASA Ames Research Center, and experiments were performed there by W. Scot Appel under the direction of Dr. John E. Finn. Modeling work was performed at the University of Virginia and at Vanderbilt University by W. Scot Appel under the direction of M. Douglas LeVan. All three participants collaborated in all of the various phases of the research. The most comprehensive document describing the research is the Ph.D. dissertation of W. Scot Appel. Results have been published in several papers and presented in talks at technical conferences. All documents have been transmitted to Dr. John E. Finn.

Phosphate-Induced Immobilization of Uranium in Hanford Sediments.

PubMed

Pan, Zezhen; Giammar, Daniel E; Mehta, Vrajesh; Troyer, Lyndsay D; Catalano, Jeffrey G; Wang, Zheming

2016-12-20

Phosphate can be added to subsurface environments to immobilize U(VI) contamination. The efficacy of immobilization depends on the site-specific groundwater chemistry and aquifer sediment properties. Batch and column experiments were performed with sediments from the Hanford 300 Area in Washington State and artificial groundwater prepared to emulate the conditions at the site. Batch experiments revealed enhanced U(VI) sorption with increasing phosphate addition. X-ray absorption spectroscopy measurements of samples from the batch experiments found that U(VI) was predominantly adsorbed at conditions relevant to the column experiments and most field sites (low U(VI) loadings, <25 μM), and U(VI) phosphate precipitation occurred only at high initial U(VI) (>25 μM) and phosphate loadings. While batch experiments showed the transition of U(VI) uptake from adsorption to precipitation, the column study was more directly relevant to the subsurface environment because of the high solid:water ratio in the column and the advective flow of water. In column experiments, nearly six times more U(VI) was retained in sediments when phosphate-containing groundwater was introduced to U(VI)-loaded sediments than when the groundwater did not contain phosphate. This enhanced retention persisted for at least one month after cessation of phosphate addition to the influent fluid. Sequential extractions and laser-induced fluorescence spectroscopy of sediments from the columns suggested that the retained U(VI) was primarily in adsorbed forms. These results indicate that in situ remediation of groundwater by phosphate addition provides lasting benefit beyond the treatment period via enhanced U(VI) adsorption to sediments.

Phosphate-Induced Immobilization of Uranium in Hanford Sediments

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

Pan, Zezhen; Giammar, Daniel E.; Mehta, Vrajesh

2016-12-20

Phosphate can be added to subsurface environments to immobilize U(VI) contamination. The efficacy of immobilization depends on the site-specific groundwater chemistry and aquifer sediment properties. Batch and column experiments were performed with sediments from the Hanford 300 Area in Washington State and artificial groundwater prepared to emulate the conditions at the site. Batch experiments revealed enhanced U(VI) sorption with increasing phosphate addition. X-ray absorption spectroscopy measurements of samples from the batch experiments found that U(VI) was predominantly adsorbed at conditions relevant to the column experiments and most field sites (low U(VI) loadings, <25 μM), and U(VI) phosphate precipitation occurred onlymore » at high initial U(VI) (>25 μM) and phosphate loadings. While batch experiments showed the transition of U(VI) uptake from adsorption to precipitation, the column study was more directly relevant to the subsurface environment because of the high solid:water ratio in the column and the advective flow of water. In column experiments, nearly six times more U(VI) was retained in sediments when phosphate-containing groundwater was introduced to U(VI)-loaded sediments than when the groundwater did not contain phosphate. This enhanced retention persisted for at least one month after cessation of phosphate addition to the influent fluid. Sequential extractions and laser-induced fluorescence spectroscopy of sediments from the columns suggested that the retained U(VI) was primarily in adsorbed forms. These results indicate that in situ remediation of groundwater by phosphate addition provides lasting benefit beyond the treatment period via enhanced U(VI) adsorption to sediments.« less

Phosphate-Induced Immobilization of Uranium in Hanford Sediments

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

Pan, Zezhen; Giammar, Daniel E.; Mehta, Vrajesh

2016-12-20

Phosphate can be added to subsurface environments to immobilize U(VI) contamination. The efficacy of immobilization depends on the site-specific groundwater chemistry and aquifer sediment properties. Batch and column experiments were performed with sediments from the Hanford 300 Area in Washington State and artificial groundwater prepared to emulate the conditions at the site. Batch experiments revealed enhanced U(VI) sorption with increasing phosphate addition. X-ray absorption spectroscopy measurements of samples from the batch experiments found that U(VI) was predominantly adsorbed at conditions relevant to the column experiments and most field sites (low U(VI) loadings, <25 μM), and U(VI) phosphate precipitation occurred onlymore » at high initial U(VI) (>25μM) and phosphate loadings. While batch experiments showed the transition of U(VI) uptake from adsorption to precipitation, the column study was more directly relevant to the subsurface environment because of the high solid:water ratio in the column and the advective flow of water. In column experiments, nearly six times more U(VI) was retained in sediments when phosphate-containing groundwater was introduced to U(VI)-loaded sediments than when the groundwater did not contain phosphate. This enhanced retention persisted for at least one month after cessation of phosphate addition to the influent fluid. Sequential extractions and laser-induced fluorescence spectroscopy of sediments from the columns suggested that the retained U(VI) was primarily in adsorbed forms. These results indicate that in situ remediation of groundwater by phosphate addition provides lasting benefit beyond the treatment period via enhanced U(VI) adsorption to sediments.« less

Interactive Mental Imagery and Short-Term Memory Search Rates for Words and Pictures. Report from the Project on Children's Learning and Development. Technical Report No. 317.

ERIC Educational Resources Information Center

Kerst, Stephen Marshall

The purposes of this study were to determine if test stimulus was a member of the memory set and if items in an interactive image held in short term memory (STM) could be scanned simultaneously. In experiment one, 50 university subjects compared a test word with a set of one to three words held in STM. The rate of STM search was obtained by…

Making Teaching Lexis and Structures to Adult EFL Learners More Effective through Creating a Learning Community and Fostering Some Specific Learning Skills: A Curriculum for a Short-Term Development Course for Non-Native Speaker EFL Teachers.

ERIC Educational Resources Information Center

Klyevanov, Oleksandr

This paper is an attempt to design a curriculum for a short-term development course for a non-native speaker English-as-a-foreign-language (EFL) teachers. The purpose is to share experiences in the effective teaching of lexis and structures; to make its participants aware of the importance of such necessities and creating a learning community and…

Influence of He-Ne laser radiation on biogenic amines content and cytochemical parameters of polymorphonuclear leukocytes in short-term stress

NASA Astrophysics Data System (ADS)

Brill, Gregory E.; Dobrovolsky, Gennady A.; Romanova, Tatyana P.; Porozova, Svetlana G.; Brill, Alexander G.

1997-06-01

In experiments on white male rats short-term immobilization- sound stress was modelled. Decrease of glycogen content and myeloperoxidase activity, increase of lysosomal cationic proteins level and NBT-test parameters as well as fall of adrenaline, dopamine and 5-hydroxytryptamine amount in polymorphonuclear leukocytes were observed. Preliminary transcutaneous He-Ne laser irradiation modified metabolic reaction of leukocytes to stress and prevented stress- induced decrease of biogenic amines content in cells.

Tropospheric NO2 and HCHO columns derived from ground-based MAX-DOAS system in Guangzhou, China and comparison with satellite observations: First results within the EU FP7 project MarcoPolo

NASA Astrophysics Data System (ADS)

Drosoglou, Theano; Kouremeti, Natalia; Bais, Alkis; Zyrichidou, Irene; Li, Shu; Balis, Dimitris; Huang, Zhonghui

2016-04-01

A miniature MAX-DOAS system, Phaethon, has been developed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece, for ground-based monitoring of column densities of atmospheric gases. Simultaneous measurements with two Phaethon systems at the city centre of Thessaloniki and at a rural location about 30 km away have shown that Phaethon provides NO2 and HCHO tropospheric column measurements of acceptable accuracy under both low and high air-pollution levels. Currently three systems have been deployed in areas with different pollution patterns to support air quality and satellite validation studies. In the framework of the EU FP7 Monitoring and Assessment of Regional air quality in China using space Observations, Project Of Long-term sino-european co-Operation, MarcoPolo project, one of the Phaethon systems has been installed since April 2015 in the Guangzhou region in China. Tropospheric NO2 and HCHO columns derived at Guangzhou during the first 10 months of operation are compared with corresponding retrievals from OMI/Aura and GOME-2/Metop-A and /Metop-B satellite sensors. The area is characterized by humid subtropical monsoon climate and cloud-free conditions are rather rare from early March to mid-October. Despite this limitation and the short period of operation of Phaethon in Guangzhou, the agreement between ground-based and satellite observations is generally good for both NO2 and HCHO. It appears that GOME-2 sensors seem to underestimate the tropospheric NO2, possibly due to their large pixel size, whereas the comparison with OMI data is better, especially when a small cloud fraction (< 0.2) is used for cloud screening.

Dutch experience with the fenestrated Anaconda endograft for short-neck infrarenal and juxtarenal abdominal aortic aneurysm repair.

PubMed

Dijkstra, Martijn L; Tielliu, Ignace F J; Meerwaldt, Robbert; Pierie, Maurice; van Brussel, Jerome; Schurink, Geert Willem H; Lardenoye, Jan-Willem; Zeebregts, Clark J

2014-08-01

In the past decennium, the management of short-neck infrarenal and juxtarenal aortic aneurysms with fenestrated endovascular aneurysm repair (FEVAR) has been shown to be successful, with good early and midterm results. Recently, a new fenestrated device, the fenestrated Anaconda (Vascutek, Renfrewshire, Scotland), was introduced. The aim of this study was to present the current Dutch experience with this device. A prospectively held database of patients treated with the fenestrated Anaconda endograft was analyzed. Decision to treat was based on current international guidelines. Indications for FEVAR included an abdominal aortic aneurysm (AAA) with unsuitable neck anatomy for EVAR. Planning was performed on computed tomography angiography images using a three-dimensional workstation. Between May 2011 and September 2013, 25 patients were treated in eight institutions for juxtarenal (n = 23) and short-neck AAA (n = 2). Median AAA size was 61 mm (59-68.5 mm). All procedures except one were performed with bifurcated devices. A total of 56 fenestrations were incorporated, and 53 (94.6%) were successfully cannulated and stented. One patient died of bowel ischemia caused by occlusion of the superior mesenteric artery. On completion angiography, three type I endoleaks and seven type II endoleaks were observed. At 1 month of follow-up, all endoleaks had spontaneously resolved. Median follow-up was 11 months (range, 1-29 months). There were no aneurysm ruptures or aneurysm-related deaths and no reinterventions to date. Primary patency at 1 month of cannulated and stented target vessels was 96%. Initial and short-term results of FEVAR using the fenestrated Anaconda endograft are promising, with acceptable technical success and short-term complication rates. Growing experience and long-term results are needed to support these findings. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

U(VI) adsorption on aquifer sediments at the Hanford Site.

PubMed

Um, Wooyong; Serne, R Jeffrey; Brown, Christopher F; Last, George V

2007-08-15

Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch K(d) values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10(-6) M (238 microg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption K(d) values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption K(d) values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected.

A "Greenhouse Gas" Experiment for the Undergraduate Laboratory

ERIC Educational Resources Information Center

Gomez, Elaine; Paul, Melissa; Como, Charles; Barat, Robert

2014-01-01

This experiment and analysis offer an effective experience in greenhouse gas reduction. Ammoniated water is flowed counter-current to a simulated flue gas of air and CO2 in a packed column. The gaseous CO2 concentrations are measured with an on-line, non- dispersive, infrared analyzer. Column operating parameters include total gas flux, dissolved…

Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

ERIC Educational Resources Information Center

Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

2011-01-01

The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

Do elite breath-hold divers suffer from mild short-term memory impairments?

PubMed

Billaut, François; Gueit, Patrice; Faure, Sylvane; Costalat, Guillaume; Lemaître, Frédéric

2018-03-01

Repeated apneas are associated with severe hypoxemia that may ultimately lead to loss of consciousness in some breath-hold divers. Despite increasing number of practitioners, the relationship between apnea-induced hypoxia and neurocognitive functions is still poorly understood in the sport of free diving. To shed light onto this phenomenon, we examined the impact of long-term breath-hold diving training on attentional processing, short-term memory, and long-term mnesic and executive functions. Thirty-six men matched for age, height, and weight were separated into the following 3 groups: (i) 12 elite breath-hold divers (EBHD), mean static apnea best time 371 s, 105 months mean apnea experience; (ii) 12 novice breath-hold divers, mean best time 243 s, 8.75 months mean apnea experience; and (iii) 12 physical education students with no breath-hold diving experience; all of these participants performed varied written and computerized neuropsychological tasks. Compared with the 2 other groups, the EBHD group was slower to complete the interference card during a Stroop test (F [1,33] = 4.70, p < 0.05), and presented more errors on the interference card (F [1,33] = 2.96, p < 0.05) and a lower total interference score (F [1,33] = 5.64, p < 0.05). The time to complete the interference card test was positively correlated with maximal static apnea duration (r = 0.73, p < 0.05) and the number of years of breath-hold diving training (r = 0.79, p < 0.001). These findings suggest that breath-hold diving training over several years may cause mild, but persistent, short-term memory impairments.

The word-length effect and disyllabic words.

PubMed

Lovatt, P; Avons, S E; Masterson, J

2000-02-01

Three experiments compared immediate serial recall of disyllabic words that differed on spoken duration. Two sets of long- and short-duration words were selected, in each case maximizing duration differences but matching for frequency, familiarity, phonological similarity, and number of phonemes, and controlling for semantic associations. Serial recall measures were obtained using auditory and visual presentation and spoken and picture-pointing recall. In Experiments 1a and 1b, using the first set of items, long words were better recalled than short words. In Experiments 2a and 2b, using the second set of items, no difference was found between long and short disyllabic words. Experiment 3 confirmed the large advantage for short-duration words in the word set originally selected by Baddeley, Thomson, and Buchanan (1975). These findings suggest that there is no reliable advantage for short-duration disyllables in span tasks, and that previous accounts of a word-length effect in disyllables are based on accidental differences between list items. The failure to find an effect of word duration casts doubt on theories that propose that the capacity of memory span is determined by the duration of list items or the decay rate of phonological information in short-term memory.

Kinetic performance of narrow-bore columns on a micro-system for high performance liquid chromatography.

PubMed

Gritti, Fabrice; Guiochon, Georges

2012-05-04

The kinetic performance of 0.5 mm × 50 mm columns packed with 2.7 μm Halo-C(18) core-shell particles and 3 μm EP-120-C(18) fully porous particles fitted on an Eksigent LC-Express Ultra μHPLC system were measured. The instrument contribution to band broadening was obtained by directly connecting the injection valve and the detector cell with a short, narrow PEEKSIL tube. The connections between the column and the connecting tubes, the column endfittings and its frits contribute to band spreading and are responsible for a significant rear peak tailing, even for retained compounds, resulting in a significant loss of efficiency. Our results show that the μHPLC system could outperform the current VHPLC systems using 2.1mm I.D. columns packed with 1.7 μm particles if it were using 0.5mm I.D. columns packed with 1 μm particles, if it could operate at a few kbar pressure drop, and if the sum of the contributions of the instrument, column endfittings and the column frits to band dispersion were three times smaller than it is at present. Copyright © 2012 Elsevier B.V. All rights reserved.

Stability and Structure of Star-Shape Granules

NASA Astrophysics Data System (ADS)

Zhao, Yuchen; Bares, Jonathan; Zheng, Matthew; Dierichs, Karola; Menges, Achim; Behringer, Robert

2015-11-01

Columns are made of convex non-cohesive grains like sand collapse after being released from initial positions. On the other hand, various architectures built by concave grains can maintain stability. We explore why these structures are stable, and how stable they can be. We performed experiments by randomly pouring identical star-shape particles into hollow cylinders left on glass and a rough base, and observed stable granular columns after lifting the cylinders. Particles have six 9 mm arms, which extend symmetrically in the xyz directions. Both the probability of creating a stable column and mechanical stability aspects have been investigated. We define r as the weight fraction of particles that fall out of the column after removing confinement. r gradually increases as the column height increases, or the column diameter decreases. We also explored different experiment conditions such as vibration of columns with confinement, or large basal friction. We also consider different stability measures such as the maximum inclination angle or maximum weight a column can support. In order to understand structure leading to stability, 3D CT scan reconstructions of columns have been done and coordination number and packing density will be discussed. We acknowledge supports from W.M.Keck Foundation and Research Triangle MRSEC.

From brief gaps to very long pauses: temporal isolation does not benefit serial recall.

PubMed

Nimmo, Lisa M; Lewandowsky, Stephan

2005-12-01

Theoretical explanations of short-term memory for serial order can be classified on the basis of whether or not they invoke time as a causal variable. According to time-based accounts, such as temporal distinctiveness theories, there is an intimate link between time and memory. Event-based theories, by contrast, postulate processes such as interference or rehearsal to account for seemingly temporal phenomena in short-term memory. We report an experiment that examined whether extended temporal isolation benefits serial recall performance. Regardless of whether the participants were quiet or performed articulatory suppression during list presentation, temporal isolation did not benefit memory even if items were separated from their neighbors by up to 7 sec. These findings challenge time-based theories of short-term memory.

Content-specificity in verbal recall: a randomized controlled study.

PubMed

Zirk-Sadowski, Jan; Szucs, Denes; Holmes, Joni

2013-01-01

In this controlled experiment we examined whether there are content effects in verbal short-term memory and working memory for verbal stimuli. Thirty-seven participants completed forward and backward digit and letter recall tasks, which were constructed to control for distance effects between stimuli. A maximum-likelihood mixed-effects logistic regression revealed main effects of direction of recall (forward vs backward) and content (digits vs letters). There was an interaction between type of recall and content, in which the recall of digits was superior to the recall of letters in verbal short-term memory but not in verbal working memory. These results demonstrate that the recall of information from verbal short-term memory is content-specific, whilst the recall of information from verbal working memory is content-general.

Use of short-term breath measures to estimate daily methane production by cattle.

PubMed

Velazco, J I; Mayer, D G; Zimmerman, S; Hegarty, R S

2016-01-01

Methods to measure enteric methane (CH4) emissions from individual ruminants in their production environment are required to validate emission inventories and verify mitigation claims. Estimates of daily methane production (DMP) based on consolidated short-term emission measurements are developing, but method verification is required. Two cattle experiments were undertaken to test the hypothesis that DMP estimated by averaging multiple short-term breath measures of methane emission rate did not differ from DMP measured in respiration chambers (RC). Short-term emission rates were obtained from a GreenFeed Emissions Monitoring (GEM) unit, which measured emission rate while cattle consumed a dispensed supplement. In experiment 1 (Expt. 1), four non-lactating cattle (LW=518 kg) were adapted for 18 days then measured for six consecutive periods. Each period consisted of 2 days of ad libitum intake and GEM emission measurement followed by 1 day in the RC. A prototype GEM unit releasing water as an attractant (GEM water) was also evaluated in Expt. 1. Experiment 2 (Expt. 2) was a larger study based on similar design with 10 cattle (LW=365 kg), adapted for 21 days and GEM measurement was extended to 3 days in each of the six periods. In Expt. 1, there was no difference in DMP estimated by the GEM unit relative to the RC (209.7 v. 215.1 g CH(4)/day) and no difference between these methods in methane yield (MY, 22.7 v. 23.7 g CH(4)/kg of dry matter intake, DMI). In Expt. 2, the correlation between GEM and RC measures of DMP and MY were assessed using 95% confidence intervals, with no difference in DMP or MY between methods and high correlations between GEM and RC measures for DMP (r=0.85; 215 v. 198 g CH(4)/day SEM=3.0) and for MY (r=0.60; 23.8 v. 22.1 g CH(4)/kg DMI SEM=0.42). When data from both experiments was combined neither DMP nor MY differed between GEM- and RC-based measures (P>0.05). GEM water-based estimates of DMP and MY were lower than RC and GEM (P<0.05). Cattle accessed the GEM water unit with similar frequency to the GEM unit (2.8 v. 3.5 times/day, respectively) but eructation frequency was reduced from 1.31 times/min (GEM) to once every 2.6 min (GEM water). These studies confirm the hypothesis that DMP estimated by averaging multiple short-term breath measures of methane emission rate using GEM does not differ from measures of DMP obtained from RCs. Further, combining many short-term measures of methane production rate during supplement consumption provides an estimate of DMP, which can be usefully applied in estimating MY.

Time-Limited Psychotherapy With Adolescents

PubMed Central

Shefler, Gaby

2000-01-01

Short-term dynamic therapies, characterized by abbreviated lengths (10–40 sessions) and, in many cases, preset termination dates, have become more widespread in the past three decades. Short-term therapies are based on rapid psychodynamic diagnosis, a therapeutic focus, a rapidly formed therapeutic alliance, awareness of termination and separation processes, and the directive stance of the therapist. The emotional storm of adolescence, stemming from both developmental and psychopathological sources, leaves many adolescents in need of psychotherapy. Many adolescents in need of therapy resist long-term attachment and involvement in an ambiguous relationship, which they experience as a threat to their emerging sense of independence and separateness. Short-term dynamic therapy can be the treatment of choice for many adolescents because it minimizes these threats and is more responsive to their developmental needs. The article presents treatment and follow-up of a 17-year-old youth, using James Mann's time-limited psychotherapy method. PMID:10793128

The Effect of Oyster Reef Morphology on Particulate Transfer in a North Carolina Tidal Creek

NASA Astrophysics Data System (ADS)

Lemon, M. G.; Posey, M.; Mallin, M.; Alphin, T.

2014-12-01

The eastern oyster (Crassostrea virginica) is a vital ecosystem engineer species, providing a number of ecosystem services that structure and maintain estuarine environments through the construction of large, hard-bottom reef complexes. Through suspension feeding, oysters clear the water column of particulates, leading to decreased suspended material and enhanced benthic pelagic coupling. Past field studies have indicated the potential importance of the physical reef structure in regulating the transfer of particulate material in the seston. In order to directly assess the existence of the physical reef effect, multiple field experiments were performed in a small tidal creek estuary along the south eastern coast of North Carolina. Comparison of clearance rates derived from two different in situ methods, one accounting for the physical structure of the oyster reef in addition to oyster filtration and one looking at oyster filtration alone, indicate that the reef structure may increase the amount of particulate removal performed by the reef by more than 4 times the removal performed by oyster filtration alone. A defaunation experiment was performed by eliminating the live component of the oyster reef and comparing particulate transfer of this defaunated transect to that of an adjacent faunated transect. The defaunated transect had reduced but not significantly lower material removal when compared to the faunated transect prior to defaunation. Results from short and long term sediment collection and flow velocity measurements indicate that the physical effect of oyster reefs is strong over short temporal scales (days) but is much smaller when evaluated over longer time periods (months). Generally, large silt and small sand sized material is permanently removed from the seston due to the interaction of oyster reef structure and tidal flows, however the transfer of small and medium sized silt grains is only slowed down by the presence of large reef complexes. This effect has important ecological implications for downstream water quality and must be accounted for when modeling water quality improvements performed by oysters.

Population Differences in Postural Response Strategy Associated with Exposure to a Novel Continuous Perturbation Stimuli: Would Dancers Have Better Balance on a Boat?

PubMed

Duncan, Carolyn A; Ingram, Tony G J; Mansfield, Avril; Byrne, Jeannette M; McIlroy, William E

2016-01-01

Central or postural set theory suggests that the central nervous system uses short term, trial to trial adaptation associated with repeated exposure to a perturbation in order to improve postural responses and stability. It is not known if longer-term prior experiences requiring challenging balance control carryover as long-term adaptations that influence ability to react in response to novel stimuli. The purpose of this study was to determine if individuals who had long-term exposure to balance instability, such as those who train on specific skills that demand balance control, will have improved ability to adapt to complex continuous multidirectional perturbations. Healthy adults from three groups: 1) experienced maritime workers (n = 14), 2) novice individuals with no experience working in maritime environments (n = 12) and 3) individuals with training in dance (n = 13) participated in the study. All participants performed a stationary standing task while being exposed to five 6 degree of freedom motions designed to mimic the motions of a ship at sea. The balance reactions (change-in-support (CS) event occurrences and characteristics) were compared between groups. Results indicate dancers demonstrated significantly fewer CS events than novices during the first trial, but did not perform as well as those with offshore experience. Linear trend analyses revealed that short-term adaptation across all five trials was dependent on the nature of participant experience, with dancers achieving postural stability earlier than novices, but later than those with offshore experience. These results suggest that long term previous experiences also have a significant influence on the neural control of posture and balance in the development of compensatory responses.

Short- and long-term impact of subtotal parathyroidectomy on the achievement of bone and mineral parameters recommended by clinical practice guidelines in dialysis patients: a 12-year single-center experience.

PubMed

Tsai, Wan-Chuan; Peng, Yu-Sen; Yang, Ju-Yeh; Hsu, Shih-Ping; Wu, Hon-Yen; Pai, Mei-Fen; Chang, Jia-Feng; Chen, Hung-Yuan

2013-01-01

The short- and long-term impact of parathyroidectomy (PTX) on the parameters of mineral bone disease in dialysis patients with severe secondary hyperparathyroidism (HPT) remains unclear. A retrospective chart review of 401 consecutive dialysis patients who underwent subtotal PTX by one surgeon was performed. We checked serum levels of calcium (Ca), phosphorus (P), and intact parathyroid hormone (iPTH) for 3 consecutive days, and then monthly for Ca, P, and tri-monthly for iPTH postoperatively. Patients with available laboratory data within the 1st to 6th postoperative months were included in the short-term follow-up group and those with at least 6 months available data were in the long-term follow-up one. Patients (short-term group, n = 401, and long-term group, n = 94) had severely uncontrolled serum iPTH levels, Ca, P and Ca × P before PTX. In the short-term group, percentages of cases achieving K/DOQI targets for serum Ca, Ca × P, and iPTH and KDIGO ones for serum Ca, P, and iPTH after PTX, significantly improved compared with those before operation (all p < 0.05). In the long-term group (mean follow-up of 43 ± 29 months), the percentage of achieved targets for serum iPTH in both guidelines and for serum Ca and Ca × P in the K/DOQI recommendation also improved postoperatively (all p < 0.05). Achievements of K/DOQI recommended values for serum Ca, Ca × P, iPTH and KDIGO recommendations for iPTH can be successfully reached by subtotal PTX in medically refractory, secondary HPT in dialysis patients both during short- and long-term follow-ups. © 2013 S. Karger AG, Basel.