866 research outputs found
Medial temporal lobe contributions to intra-item associative recognition memory in the aging brain
Aging is associated with a decline in episodic memory function. This is accompanied by degradation of and functional changes in the medial temporal lobe (MTL) which subserves mnemonic processing. To date no study has investigated age-related functional change in MTL substructures during specific episodic memory processes such as intra-item associative memory. The aim of this study was to characterize age-related change in the neural correlates of intra-item associative memory processing. Sixteen young and 10 older subjects participated in a compound word intra-item associative memory task comprising a measure of associative recognition memory and a measure of recognition memory. There was no difference in performance between groups on the associative memory measure but each group recruited different MTL regions while performing the task.The young group recruited the left anterior hippocampus and posterior parahippocampal gyrus whereas the older participants recruited the hippocampus bilaterally. In contrast, recognition memory was significantlyworse in the older subjects.The left anterior hippocampuswas recruited in the young group during successful recognition memory whereas the older group recruited a more posterior region of the left hippocampus and showed a more bilateral activation of frontal brain regions than was observed in the young group. Our results suggest a reorganization of the neural correlates of intra-item associative memory in the aging brain
Dynamics of Labor Demand: Evidence from Plant-level Observations and Aggregate Implications
This paper studies the dynamics of labor demand at the plant and aggregate levels. The correlation of hours and employment growth is negative at the plant level and positive in aggregate time series. Further, hours and employment growth are about equally volatile at the plant level while hours growth is much less volatile than employment growth in the aggregate data. Given these differences, we specify and estimate the parameters of a plant-level dynamic optimization problem using simulated method of moments to match plant-level observations. Our findings indicate that non-convex adjustment costs are critical for explaining plant-level moments on hours and employment. Aggregation generates time series implications which are broadly consistent with observation. Further, we find that a model with quadratic adjustment costs alone can also broadly match the aggregate facts.
A novel fabrication process for capacitive cantilever structures for smart fabric applications
This paper reports, for the first time, capacitive freestanding cantilever beams fabricated by screen printing sacrificial and structural materials onto a fabric/textile. Unlike traditional weaving process, the device will be screen printed layer by layer with desired pattern onto the fabric substrate. Free standing structures will be fabricated directly onto fabrics rather than other methods such as bonding or embedding. In addition, a low temperature removable sacrificial material capable for the removal conditions on fabrics will also be reported
Community Empowerment as a Non-Problem
It is not much fun to be a radical any more -- as a student, a teacher or a community activist. Often it seems as if there are too many battles and not enough time to begin to fight them. The privileged position in which many on the left found themselves in years past has given way to the treatment usually accorded persons with serious contagious diseases. Feeling unappreciated, unneeded and unwanted, we have tended to become a bit cranky and hypercritical. In our frustration, we have fallen prey to an isolation that encourages us to think only of people who see the world exactly as we do as allies
Embedding ecosystem services ideas into policy processes: an institutional analysis
What helps or limits the use of ecosystem services ideas in practice? In this paper we develop and test a new institutionalistbased analytical scheme to explore how ecosystem services as a “new” policy idea might interact with established policy regimes, processes, and norms. The scheme is based on three different decision-making levels: micro, meso, and macro. To test the plausibility of the scheme, it is applied to the case of the UK where a specific ecosystem services framework (ESF) was prioritized as a new way of doing environmental policy after 2011. Drawing on findings from 32 elite interviews, the paper shows how dynamics at all three levels intersect with differing institutional explanations. It helps explain important factors for embedding, or restricting embedding, of the ESF in policy making. The scheme provides a useful way to link analysis of the “lived experience” of policy actors implementing the ESF with the institutional landscape they occupy, and allows for a nuanced and integrated analysis of the potential barriers faced by ecosystem services ideas generally
A study of the influence of some processing variables on the performance of the fuel electrode of a fuel cell
Improved power source and energy conversion systems represent one of the most important long range problems facing the world. This is leading us to direct energy conversion systems
Keck NIRSPEC Radial Velocity Observations of Late-M dwarfs
We present the results of an infrared spectroscopic survey of 23 late-M
dwarfs with the NIRSPEC echelle spectrometer on the Keck II telescope. Using
telluric lines for wavelength calibration, we are able to achieve measurement
precisions of down to 45 m/s for our late-M dwarfs over a one to four year-long
baseline. Our sample contains two stars with RV variations of >1000 m/s. While
we require more measurements to determine whether these RV variations are due
to unseen planetary or stellar companions or are the result of starspots known
to plague the surface of M dwarfs, we can place upper limits of <40 MJsini on
the masses of any companions around those two M dwarfs with RV variations of
<160 m/s at orbital periods of 10-100 days. We have also measured the
rotational velocities for all the stars in our late-M dwarf sample and offer
our multi-order, high-resolution spectra over 2.0 to 2.4 micron to the
atmospheric modeling community to better understand the atmospheres of late-M
dwarfs.Comment: Accepted to Ap
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