18,973 research outputs found
Improved intensifying screen reduces X-ray exposure
X-ray intensifying screen may make possible radiographic procedures where detection speed and X-ray tube power have been the limiting factors. Device will reduce total population exposure to harmful radiation in the United States
Recommended from our members
The Ancient Past: Learning a Language to Connect Materials with Users
Archives of the ancient world evince the longevity of our
shared interests in preserving and documenting the
culture, government, and knowledge of civilization.
Whether studied by global travelers, classical archaeologists
and historians, or filmmakers and television producers,
archival materials from the ancient Mediterranean are
contributing to collective memory, educational programming,
and institutional collections.
In this vein, the Program in Aegean Scripts and Prehistory
(PASP) in the Department of Classics at The University of
Texas at Austin fosters research and scholarship on the use of
writing in Minoan Crete, Mycenaean Greece, and the island
of Cyprus during the Bronze Age. There is a special focus on
two early writing systems: Linear A and Cretan hieroglyphics
(1900–1450 BCE) and Linear B (1400–1200 BCE).
The program boasts an international base of researchers and
users, and in recent years, staff have improved collection
accessibility by reconfiguring physical spaces, advancing
digitization projects, preserving endangered email accounts,
and expanding the scope of collections to provide better
access to these important materials.Classic
Value stability and change during self-chosen life transitions: Self-selection versus socialization effects
Copyright @ 2013 APA. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.Three longitudinal studies examine a fundamental question regarding adjustment of personal values to self-chosen life transitions: Do values fit the new life setting already at its onset, implying value-based self-selection? Or do values change to better fit the appropriate and desirable values in the setting, implying value socialization? As people are likely to choose a life transition partly based on their values, their values may fit the new life situation already at its onset, leaving little need for value socialization. However, we propose that this may vary as a function of the extent of change the life transition entails, with greater change requiring more value socialization. To enable generalization, we used 3 longitudinal studies spanning 3 different life transitions and different extents of life changes: vocational training (of new police recruits), education (psychology vs. business students), and migration (from Poland to Britain). Although each life transition involved different key values and different populations, across all 3 studies we found value fit to the life situation already early in the transition. Value socialization became more evident the more aspects of life changed as part of the transition, that is, in the migration transition. The discussion focuses on the implications of these findings for research on values and personality change, as well as limitations and future directions for research
Mathematical Analysis and Simulations of the Neural Circuit for Locomotion in Lamprey
We analyze the dynamics of the neural circuit of the lamprey central pattern
generator (CPG). This analysis provides insights into how neural interactions
form oscillators and enable spontaneous oscillations in a network of damped
oscillators, which were not apparent in previous simulations or abstract phase
oscillator models. We also show how the different behaviour regimes
(characterized by phase and amplitude relationships between oscillators) of
forward/backward swimming, and turning, can be controlled using the neural
connection strengths and external inputs.Comment: 4 pages, accepted for publication in Physical Review Letter
Recommended from our members
Experimental In-Field Transfer and Survival of Escherichia coli from Animal Feces to Romaine Lettuce in Salinas Valley, California.
This randomized controlled trial characterized the transfer of E. coli from animal feces and/or furrow water onto adjacent heads of lettuce during foliar irrigation, and the subsequent survival of bacteria on the adaxial surface of lettuce leaves. Two experiments were conducted in Salinas Valley, California: (1) to quantify the transfer of indicator E. coli from chicken and rabbit fecal deposits placed in furrows to surrounding lettuce heads on raised beds, and (2) to quantify the survival of inoculated E. coli on Romaine lettuce over 10 days. E. coli was recovered from 97% (174/180) of lettuce heads to a maximal distance of 162.56 cm (5.33 ft) from feces. Distance from sprinklers to feces, cumulative foliar irrigation, and lettuce being located downwind of the fecal deposit were positively associated, while distance from fecal deposit to lettuce was negatively associated with E. coli transference. E. coli exhibited decimal reduction times of 2.2 and 2.5 days when applied on the adaxial surface of leaves within a chicken or rabbit fecal slurry, respectively. Foliar irrigation can transfer E. coli from feces located in a furrow onto adjacent heads of lettuce, likely due to the kinetic energy of irrigation droplets impacting the fecal surface and/or impacting furrow water contaminated with feces, with the magnitude of E. coli enumerated per head of lettuce influenced by the distance between lettuce and the fecal deposit, cumulative application of foliar irrigation, wind aspect of lettuce relative to feces, and time since final irrigation. Extending the time period between foliar irrigation and harvest, along with a 152.4 cm (5 ft) no-harvest buffer zone when animal fecal material is present, may substantially reduce the level of bacterial contamination on harvested lettuce
The Activity Requirements for Spike Timing-Dependent Plasticity in the Hippocampus
Synaptic plasticity has historically been investigated most intensely in the hippocampus and therefore it is somewhat surprising that the majority of studies on spike timing-dependent plasticity (STDP) have focused not in the hippocampus but on synapses in the cortex. One of the major reasons for this bias is the relative ease in obtaining paired electrophysiological recordings from synaptically coupled neurons in cortical slices, in comparison to hippocampal slices. Another less obvious reason has been the difficulty in achieving reliable STDP in the hippocampal slice preparation and confusion surrounding the conditions required. The original descriptions of STDP in the hippocampus was performed on paired recordings from neurons in dissociated or slice cultures utilizing single pairs of presynaptic and postsynaptic spikes and were subsequently replicated in acute hippocampal slices. Further work in several laboratories using conditions that more closely replicate the situation in vivo revealed a requirement for multiple postsynaptic spikes that necessarily complicate the absolute timing rules for STDP. Here we review the hippocampal STDP literature focusing on data from acute hippocampal slice preparations and highlighting apparently contradictory results and the variations in experimental conditions that might account for the discrepancies. We conclude by relating the majority of the available experimental data to a model for STDP induction in the hippocampus based on a critical role for postsynaptic Ca2+ dynamics
Preparation of Isolated Blood Capillaries
Blood capillaries have been isolated from various tissue sources yielding suspensions of capillary segments. These have provided opportunities to study the cellular properties of capillary endothelium under conditions uncomplicated by the presence of stromal tissues and in which measured parameters can be attributed to endothelial cells. Fresh capillary isolates have been used directly as experimental systems but the yield of endothelium is quite low. Amplification of endothelial biomass has been accomplished by using freshly isolated capillaries as explants for primary tissue culture. It has not been previously possible, however, to obtain large amounts of capillary endothelium from a single preparation nor have different capillary types been isolated from the same tissue. The rete mirabile of the eel swim bladder is a copious source of capillaries of two types: thick-walled, continuous capillaries heavily invested with pericytes and thin-walled, fenestrated capillaries. These can be isolated in large numbers free of large blood vessels and contaminating stromal tissue. The two types of capillaries can be isolated from each other by perfusing magnetic beads into one type prior to isolation and separating them from the other type in a magnetic field. This provides a system in which the cellular properties of the two types of endothelium can be studied in vitro and, due to a common isolation procedure, direct comparisons can be made
Recommended from our members
Phonological working memory impacts on information searching: An investigation of dyslexia
A key aspect of searching is the ability of users to absorb information from documents read in order to resolve their ask. One group of users who have problems with reading are dyslexic users, who due to underlying cognitive impairments in phonological processing and working memory, tend to read more slowly and make reading errors. The purpose of this study is to examine the impact of the dyslexia cognitive profile on information searching. Searches were logged for 8 dyslexic and 8 non-dyslexic university students, in order to examine the differences in searching behavior between the two groups. A set of literacy and phonological working memory tasks were also completed, in order to investigate the relationship between these cognitive variables and searching behavior. Results show that there is a significant difference between the two groups on the number of documents being judged irrelevant, and that this cannot be explained by a topic effect. Instead, the number of documents judged irrelevant is significantly correlated with a measure of working memory. This key result provides the research community the first real insight into impact of impaired short term memory on information searching
Value stability and change during self-chosen life transitions: self-selection versus socialization effects
Three longitudinal studies examine a fundamental question regarding adjustment of personal values to self-chosen life transitions: Do values fit the new life setting already at its onset, implying value-based self-selection? Or do values change to better fit the appropriate and desirable values in the setting, implying value socialization? As people are likely to choose a life transition partly based on their values, their values may fit the new life situation already at its onset, leaving little need for value socialization. However, we propose that this may vary as a function of the extent of change the life transition entails, with greater change requiring more value socialization. To enable generalization, we used 3 longitudinal studies spanning 3 different life transitions and different extents of life changes: vocational training (of new police recruits), education (psychology vs. business students), and migration (from Poland to Britain). Although each life transition involved different key values and different populations, across all 3 studies we found value fit to the life situation already early in the transition. Value socialization became more evident the more aspects of life changed as part of the transition, that is, in the migration transition. The discussion focuses on the implications of these findings for research on values and personality change, as well as limitations and future directions for research
- …