Contribution of reactive and proactive control to children's working memory performance:Insight from item recall durations in response sequence planning

The present study addressed whether developmental improvement in working memory span task performance relies upon a growing ability to proactively plan response sequences during childhood. Two hundred thirteen children completed a working memory span task in which they used a touchscreen to reproduce orally presented sequences of animal names. Children were assessed longitudinally at 7 time points between 3 and 10 years of age. Twenty-one young adults also completed the same task. Proactive response sequence planning was assessed by comparing recall durations for the 1st item (preparatory interval) and subsequent items. At preschool age, the preparatory interval was generally shorter than subsequent item recall durations, whereas it was systematically longer during elementary school and in adults. Although children mostly approached the task reactively at preschool, they proactively planned response sequences with increasing efficiency from age 7 on, like adults. These findings clarify the nature of the changes in executive control that support working memory performance with age

Relationships between oceanic epizooplankton distributions and the seasonal deep chlorophyll maximum in the northwestern Atlantic Ocean

Also published as: Journal of Marine Research 38 (1980): 507-531The potential significance of the Deep Chlorophyll Maximum (DCM) as a food resource for pelagic food chains was studied in three hydrographic regimes of the Northwestern Atlantic Ocean: the Slope Water, the Northern Sargasso Sea and a Gulf Stream cold core ring. Samples for phytoplankton species, chlorophyll and related water chemistry were obtained with a series of water bottle casts from the upper 200 m; microzooplankton and macrozooplankton were also obtained in the upper 200 m with Clarke Bumpus (67 m mesh) and MOCNESS (333 m mesh) net systems. Samples were obtained in the summer when the DCM was well developed and in the fall when mixing had erased the DCM in most areas. Total zooplankton biomass was significantly enhanced within depth intervals including or adjacent to the seasonal thermocline in the three hydrographic areas. Hydrocast data show the DCM in these regions was predictably associated with the seasonal thermocline. Thus these data indicate zooplankton biomass was enhanced about the DCM when it was present. In some cases, the zooplankton assemblage at DCM depths was distinguishable from those both at deeper and more shallow depths and its composition appeared related to the food available at DCM depths. Overall, in environments ranging from moderately rich near-shore Slope Waters to the more oligotrophic open-ocean Sargasso Sea, our data suggest that the DCM signals a depth zone of particularly intense trophic activity.Prepared for the Office of Naval Research under Contracts N00014-66-C-0241; NR 083-004; N00014-74-C-0262; NR 083- 004 and the National Science Foundation under Grant DES 02?83A1

Limits of Nematoscelis megalops in the northwestern Atlantic in relation to Gulf Stream cold core rings. II, Physiological and biochemical effects of expatriation

Originally published in the Journal of Marine Research, v. 36, 1, 1978, pp. 143-159Nematoscelis megalops, a cold water euphausiid commonly found in Northwestern Atlantic Slope Water, is frequently transported in the cores of Gulf Stream cyclonic rings into the Sargasso Sea. The inner core made of cold Slope Water gradually assumes physical and biological characteristics of the surrounding Sargasso Sea. These changes gradually lead to a localized extinction of this species in the core of the ring. Samples of N. megalops taken from the same ring at 6 and 9 months after its formation show a weakened physiological and biochemical condition. Deterioration of ring individuals is evidenced by an increase in body water content and a reduction in total body lipid, carbon, respiration rates, and nitrogen relative to Slope Water individuals. By 6 months it appears that ring N. megalops must supplement food intake by metabolizing some of their body protein and by 9 months they appear to use lipids as well. A shipboard starvation experiment involving 40 Slope Water individuals showed that physiological and biochemical states similar to those found in individuals from the 9 months old ring could be duplicated in 4 days of complete starvation.Prepared for the Office of Naval Research under Contracts N00014-66-C-0241; NR 083-004 and N00014-?4-C-0262; NR 083-004 and for the National Science Foundation under Grant DES ?4-02?83 A01

Computational Thinking Integration into Middle Grades Science Classrooms: Strategies for Meeting the Challenges

This paper reports findings from the efforts of a university-based research team as they worked with middle school educators within formal school structures to infuse computer science principles and computational thinking practices. Despite the need to integrate these skills within regular classroom practices to allow all students the opportunity to learn these essential 21st Century skills, prior practice has been to offer these learning experiences outside of mainstream curricula where only a subset of students have access. We have sought to leverage elements of the research-practice partnership framework to achieve our project objectives of integrating computer science and computational thinking within middle science classrooms. Utilizing a qualitative approach to inquiry, we present narratives from three case schools, report on themes across work sites, and share recommendations to guide other practitioners and researchers who are looking to engage in technology-related initiatives to impact the lives of middle grades students

The influences of spatially variable rainfall and localized infiltration on groundwater recharge in a water management context

Water management involves monitoring, predicting, and stewarding the quality and quantity of groundwater recharge at the watershed scale. Recharge sustains baseflow to streams and replenishes water extracted by pumping at wells; it is frequently estimated using numerical models that couple or fully integrate surface water and groundwater domains and use water budgets to partition water into various components of the hydrological cycle. However, uncertainty associated with the input data for large components such as precipitation and evapotranspiration may hinder model accuracy, and preferential flow dynamics such as depression focused recharge (DFR) may not be represented at typical modelling scales (≥10s of sq. km) or with typical approaches. The present study addressed two themes related to groundwater sustainability and vulnerability: 1) the sensitivity of modelled recharge estimates to the spatial variability of rainfall, and 2) the vulnerability of public supply wells to DFR during large-magnitude rainfall or snowmelt events. The region investigated during this research was the Alder Creek watershed (78 sq. km), a typical southern Ontario setting overlying glacial moraine sediments with mostly agricultural land use, some urban and aggregate resource development, and whose recharge supplies multiple municipal well fields for the cities of Kitchener and Waterloo. Rainfall is often the largest component of the water budget and even a small uncertainty percentage may lead to challenges for accurately estimating groundwater recharge as a calculated residual within a water budget approach. However, rainfall monitoring networks typically have widely spaced gauges that are frequently outside the watershed of interest. Assessment of the influence of spatially variable rainfall on annual recharge rate estimates was performed by comparing transient simulations using input data from three different rain gauge networks within a coupled and fully-distributed numerical model. A local network of six weather stations with rain gauges was installed and operated in and around the study watershed for three years, and data from six regional stations (within 30 km of the watershed) and one national station (3 km from the watershed) were obtained from publicly available sources. Time series of distributed, daily rainfall were interpolated via the inverse distance squared method using data from each of the rain gauge networks for three calendar years. The temporal and spatial snowfall distribution was consistent among all scenarios, to maintain focus on differences caused by the rainfall input data. Results showed that annual average recharge rates could differ considerably between scenarios, with differences sometimes greater than the water-budget derived uncertainty for recharge. Differences in overall recharge between pairs of scenarios involving the local rain gauge network were largest, varying by up to 141 mm per year, or 44% of the steady state recharge estimated in a previous study. Streamflow estimates for the local rainfall simulations were closer to observations than those using regional or national rainfall. Because the three scenarios used the same set of underlying soil parameters, the results suggest that the availability of local rainfall measurements has the potential to improve the calibration of transient watershed hydrogeological models. The second theme of the present study was exemplified by the Walkerton tragedy in 2000, where pathogenic microbes were rapidly transported from ground surface to a public supply well during a heavy rainfall event. The vulnerability of such wells to surface-originating contaminants during major hydrological events remains poorly understood and is difficult to quantify. Such events may result in overland flow collecting in low topographic locations, leading to localized infiltration. If focused recharge occurs in the immediate vicinity of a public supply well, the threat to the water quality of that well may significantly increase temporarily. These conditions are frequently encountered within the glaciated landscape of southern Ontario. Conventional approaches for defining the threat of groundwater under the direct influence of surface water (GUDI) do not routinely account for this type of transient infiltration event and instead assume steady state flow fields without localized recharge. The present study combined the monitoring and modelling of a site in southern Ontario where DFR is routinely observed to occur within 50 m of a public supply well. Extensive site characterization and hydrologic monitoring were conducted at the site over a period of 3.5 years, specifically during large-magnitude hydrologic events including heavy rainfall and snowmelt. Integrated surface water – groundwater models employing HydroGeoSphere (HGS) were used to quantify the transport of potential contaminants infiltrating beneath a depression and a creek and the associated risk to the public supply well. Simulated relative concentrations at the well were below “detection” for typical median contaminant concentrations in surface water but > 1 cfu/100 mL with travel times between 118 and 142 days for creek and DFR solutes, respectively, based on maximum initial surface water concentrations. Results suggest that DFR and localized recharge could increase the threat to overburden wells under extreme conditions. Ponding reduced travel time by at least 58 days for the DFR solute. In order to extend the analysis of recharge estimate sensitivity to spatial rainfall variability to the longer term, and to incorporate the influence of actual evapotranspiration (AET) uncertainty, a method was developed to employ stochastic rainfall time series and AET estimates in a Monte Carlo framework to quantify the resulting variability in recharge estimates and three groundwater management metrics. Stochastic rainfall time series were generated via a parametric, mixed exponential method for three virtual stations within the Alder Creek watershed and constrained by field-derived spatial correlation coefficients. Observed snowfall data from one nearby national weather station were used to calculate total precipitation. Stochastic annual AET estimates were generated based on: 1) calculated annual potential evapotranspiration at the national weather station, 2) observed variation about the Budyko curve in 45 US MOPEX watersheds with PET/P ratios within ±0.05 of the average ratio calculated for the national weather station near the watershed, and 3) a correction factor to remove AET from the saturated zone. Recharge rates for the Alder Creek watershed were calculated via a 46-year vadose zone water budget for each of 16,778 realizations. The surface water fraction of streamflow was estimated using hydrograph separation results for the watershed. It was hypothesized that spatially variable precipitation would exert more influence on recharge than AET because it is a larger component of the local water budget. Groundwater recharge results were applied to three different metrics related to water quality, well vulnerability, and water quantity. Results suggest that estimates of non-point source contaminant loadings to the water table could differ by up to ±14% from the average. Worst case changes in capture zone area estimates for a public supply well could be up to ±15% different from the average. The ratio of maximum to minimum cumulative recharge over all realizations was 1.31, though contributions from spatial rainfall variability alone led to a ratio of 1.15. This suggests that AET uncertainty and spatial rainfall variability each contribute nearly the same amount of variability to recharge estimates. This latter ratio is less than the result (~2) from a previous study of a much larger watershed in Spain. The results highlight the importance of AET estimates for recharge rate estimation, and their potential impacts on land use planning and groundwater management. This method could be used to project impacts of climate change on recharge variability at the watershed scale. Overall, results suggest that the spatial variability of rainfall could impact recharge rate estimates in numerical models of small to medium sized watersheds (e.g., 78 sq. km), especially during short simulations. Annual recharge estimates could vary over a range equivalent to 44% of a previously estimated steady state value, though long-term (46-yr) estimates could vary over a range equivalent to 12% of this value due to averaging over time. Non-point source loadings and capture zone areas could vary up to ±7.0% and ±7.4% from the average, respectively, over the long term due to spatial rainfall variability, though uncertainties associated with AET could increase this to ±14% or ±15%, respectively. The hydrological event characterization and well vulnerability modelling of the second research theme suggest that localized recharge could lead to increased microbial risks for wells screened in overburden sediments during large hydrological events (≥ 40 mm rainfall over 4 days) through the phenomenon of temporary ponding. The method developed for the long-term stochastic recharge rate analysis could be applied in other settings as an alternative to, or to complement, large-scale, fully-distributed 3D numerical modelling

Quantifying the Groundwater Component within the Water Balance of a Large Lake in a Glaciated Watershed: Lake Pyhäjärvi, SW Finland

Accurate estimates of the amount of groundwater entering a lake on a yearly basis may provide valuable information for assessing contaminant loadings such as nutrient mass fluxes and the subsequent contribution of groundwater to eutrophication. Groundwater exchange with lakes is often a critical component of a lake’s water balance, yet its quantification has often proven problematic. Large component uncertainties preclude accurate estimation of the groundwater flux, upon which the assessment of contaminant loadings may depend. In this study, water balance techniques for lake systems were assessed at Lake Pyhäjärvi (near Säkylä, SW Finland), a relatively large lake in a long established agricultural area. A water balance was conducted over 38 water years to estimate the net groundwater discharge into the lake. This was compared with groundwater flux estimates via Darcy’s Law for the adjacent Honkala Aquifer in the Kuivalahti-Säkylä tributary esker (a potential conduit for groundwater impacted by agricultural practices). Direct runoff estimates were initially made using an average of river flow per unit area ratios from the two rivers that flow into the lake. Adjustments to these estimates were made using PART (Rutledge, 2007) hydrograph separation results from the larger river. The mean net groundwater discharge increased from -73 to +38mm per unit lake area (-4.8 to +2.5% of average total inflow) due to these adjustments, which yielded a better qualitative match with observations at the lake (e.g., Rautio, 2009; Rautio and Korkka-Niemi, 2011). Uncertainty analysis for the water balance indicated that relative uncertainty ranged from 40 to 2900% on the net groundwater flux, while the average absolute uncertainty was 118mm per unit lake area. Groundwater discharge estimates based on Darcy’s Law were ≤ 22 mm per unit lake area (≤1.4% of average total inflow) with sizeable uncertainty (± one order of magnitude). Most of the uncertainty on the net groundwater discharge estimates was incurred from the evaporation, precipitation, and direct runoff components; esker flux uncertainty was essentially due to error on the hydraulic conductivity estimate. The resolution of the water balance method suggests that it is better suited to lakes with relatively large net groundwater contributions (>5% of average total inflow). Results highlight the following needs for large lake water balances: improvements in the accuracy of evaporation, precipitation, and direct runoff component estimates; and uncertainty analysis. Groundwater contributions to inflow rivers may be more important than direct discharge from highly permeable subsurface materials adjacent to lakes in the context of understanding nutrient loadings to large lakes

Implications Of The Caacb Virus Contamination In Biomanufacturing Project For Cell Therapy Manufacturers

Adventitious agent contamination of cell culture-based biomanufacturing operations for the production of protein and monoclonal antibody biotherapeutics are infrequent, but when they do occur, they are very costly, impact manufacturing operations, and can potentially impact patient safety and product supply. In response to this need, the MIT Consortium on Adventitious Agent Contamination in Biomanufacturing (CAACB) began the confidential collection and analysis of industry-wide viral contamination data with an emphasis on “lessons learned”. This presentation will cover the learnings from this study, including identified industry risks and best practices to mitigate those risks. Some of the key findings which have significant implications to the emerging cell therapy industry are: 1) Raw materials, including non-animal-based raw materials, may be a potential source of viral contamination and stringent raw material testing and vendor selection and auditing programs are critical. 2) Traditional viral tests, including in vitro testing and PCR, have contributed to false-positive events, which may take extended times to resolve prior to release of raw materials, process intermediates, or final product. 3) The time frames needed for viral testing in general, and for investigation of positive viral tests, can range from weeks to months, and are not compatible with the requirements for near real-time release testing for some cell therapy products. 4) Viral testing programs, and potential investigations of positive results, are quite expensive, and application to the autologous cell therapy space will be challenging

Design in the Age of Information: A Report to the National Science Foundation (NSF)

The Information Age is upon us - it has become a global force in our everyday lives. But the promise of significant benefits from this revolution, which has been driven largely by technologists, will not be realized without more careful planning and design of information systems that can be integral to the simultaneously emerging user-cultures. In cultural terms, information systems must be effective, reliable, affordable, intuitively meaningful, and available anytime and everywhere. In this phase of the information revolution, design will be essential

New measurement paradigms

This collection of New Measurement Paradigms papers represents a snapshot of the variety of measurement methods in use at the time of writing across several projects funded by the National Science Foundation (US) through its REESE and DR K–12 programs. All of the projects are developing and testing intelligent learning environments that seek to carefully measure and promote student learning, and the purpose of this collection of papers is to describe and illustrate the use of several measurement methods employed to achieve this. The papers are deliberately short because they are designed to introduce the methods in use and not to be a textbook chapter on each method. The New Measurement Paradigms collection is designed to serve as a reference point for researchers who are working in projects that are creating e-learning environments in which there is a need to make judgments about students’ levels of knowledge and skills, or for those interested in this but who have not yet delved into these methods