4,870 research outputs found
Automatic vigilance for negative words in lexical decision and naming : comment on Larsen, Mercer, and Balota (2006)
An automatic vigilance hypothesis states that humans preferentially attend to negative stimuli, and this attention to negative valence disrupts the processing of other stimulus properties. Thus, negative words typically elicit slower color naming, word naming, and lexical decisions than neutral or positive words. Larsen, Mercer, and Balota (see record 2006-04603-006) analyzed the stimuli from 32 published studies, and they found that word valence was confounded with several lexical factors known to affect word recognition. Indeed, with these lexical factors covaried out, Larsen et al. found no evidence of automatic vigilance. The authors report a more sensitive analysis of 1011 words. Results revealed a small but reliable valence effect, such that negative words (e.g., "shark") elicit slower lexical decisions and naming than positive words (e.g., "beach"). Moreover, the relation between valence and recognition was categorical rather than linear; the extremity of a word's valence did not affect its recognition. This valence effect was not attributable to word length, frequency, orthographic neighborhood size, contextual diversity, first phoneme, or arousal. Thus, the present analysis provides the most powerful demonstration of automatic vigilance to date
Automatic vigilance for negative words is categorical and general
With other factors controlled, negative words elicit slower lexical decisions and naming than positive words (Estes & Adelman, 2008; see record 2008-09984-001). Moreover, this marked difference in responding to negative words and to positive words (i.e., between-category discontinuity) was accompanied by relatively uniform responding among negative words (i.e., within-category equivalence), thus suggesting a categorical model of automatic vigilance. Larsen, Mercer, Balota, and Strube (this issue; see record 2008-09984-002) corroborated our observation that valence predicts lexical decision and word naming latencies. However, on the basis of an interaction between linear arousal and linear valence, they claim that automatic vigilance does not occur among arousing stimuli and they purport to reject the categorical model. Here we show that (a) this interaction is logically irrelevant to whether automatic vigilance is categorical; (b) the linear interaction is statistically consistent with the categorical model; (c) the interaction is not observed within the categorical model; and (d) despite having 5 fewer parameters, the categorical model predicts word recognition times as well as the interaction model. Thus, automatic vigilance is categorical and generalizes across levels of arousa
New Concepts in Pacemaker Syndrome
After implantation of a permanent pacemaker, patients may experience severe symptoms of dyspnea, palpitations, malaise, and syncope resulting from pacemaker syndrome. Although pacemaker syndrome is most often ascribed to the loss of atrioventricular (A-V) synchrony, more recent data may also implicate left ventricular dysynchrony caused by right ventricular pacing. Previous studies have not shown reductions in mortality or stroke with rate-modulated dual-chamber (DDDR) pacing as compared to ventricular-based (VVI) pacing. The benefits in A-V sequential pacing with the DDDR mode are likely mitigated by the interventricular (V-V) dysynchrony imposed by the high percentage of ventricular pacing commonly seen in the DDDR mode. Programming DDDR pacemakers to encourage intrinsic A-V conduction and reduce right ventricular pacing will likely decrease heart failure and pacemaker syndrome. Studies are currently ongoing to address these questions
Letter from S. H. Estes to T. B. Larimore
Letter from S. H. Estes to T. B. Larimore. The four-page handwritten letter is dated 16 November 1912. There is a transcript of the correspondence in the item PDF
The unexplained nature of reading.
The effects of properties of words on their reading aloud response times (RTs) are 1 major source of evidence about the reading process. The precision with which such RTs could potentially be predicted by word properties is critical to evaluate our understanding of reading but is often underestimated due to contamination from individual differences. We estimated this precision without such contamination individually for 4 people who each read 2,820 words 50 times each. These estimates were compared to the precision achieved by a 31-variable regression model that outperforms current cognitive models on variance-explained criteria. Most (around 2/3) of the meaningful (non-first-phoneme, non-noise) word-level variance remained unexplained by this model. Considerable empirical and theoretical-computational effort has been expended on this area of psychology, but the high level of systematic variance remaining unexplained suggests doubts regarding contemporary accounts of the details of the mechanisms of reading at the level of the word. Future assessment of models can take advantage of the availability of our precise participant-level database
Two Stage Peroxide-Borohydride Bleaching of Cold Soda Pulp
Survey of Literature
Introduction
Since the development of cold soda pulping in the early 1950\u27s, the search for suitable bleaching methods has been of primary concern. Cold soda pulp is dark brown in color and resists the bleaching action of most chemicals. Marton (1) suggests that this brown discoloration of hardwood cold soda pulp is due to a material in the cells of the wood, primarily in the heartwood. These substances, which have not been identified, are not the same as lignin but probably develop in a similar manner.
The chemicals most often used in bleaching hardwood cold soda pulps have been peroxides, hypochlorites, hydrosulfites, and most recently borohydrides. A satisfactory bleaching procedure should meet the following objectives:
1. Development of high brightness
2. Retention of the initial high yield
3. Low cost
In order to achieve these objectives Giertz (2) states that the pulping process should be performed in such a manner that colored lignins do not form and that the bleaching agent should destroy only the coloring material and not react with the lignin. These requirements would eliminate all chlorine compounds which form colored lignin complexes as bleaching agents
Application of remote sensing to selected problems within the state of California
Specific case studies undertaken to demonstrate the usefulness of remote sensing technology to resource managers in California are highlighted. Applications discussed include the mapping and quantization of wildland fire fuels in Mendocino and Shasta Counties as well as in the Central Valley; the development of a digital spectral/terrain data set for Colusa County; the Forsythe Planning Experiment to maximize the usefulness of inputs from LANDSAT and geographic information systems to county planning in Mendocino County; the development of a digital data bank for Big Basin State Park in Santa Cruz County; the detection of salinity related cotton canopy reflectance differences in the Central Valley; and the surveying of avocado acreage and that of other fruits and nut crops in Southern California. Special studies include the interpretability of high altitude, large format photography of forested areas for coordinated resource planning using U-2 photographs of the NASA Bucks Lake Forestry test site in the Plumas National Forest in the Sierra Nevada Mountains
Observations from Space: A Unique Vantage Point for the Study of the Environment and Possible Associations with Disease Occurrence
Health providers/researchers need environmental data to study and understand the geographic, environmental, and meteorological differences in disease. Satellite remote sensing of the environment offers a unique vantage point that can fill in the gaps of environmental, spatial, and temporal data for tracking disease. The field of geospatial health remains in its infancy, and this program will demonstrate the need for collaborations between multi-disciplinary research groups to develop the full potential. NASA will discuss the Public Health Projects developed to work with Grantees and the CDC while providing them with information on opportunities for future collaborations with NASA for future research
Application of remote sensing to selected problems within the state of California
There are no author-identified significant results in this report
Comparison of the pharmacokinetic properties of vancomycin, linezolid, tigecyclin, and daptomycin
The rapid antibiotic resistance development has created a major demand for new antimicrobial agents that can combat resistant strains such as methicillin-resistant S. aureus (MRSA). Until a short time ago, the glycopeptide vancomycin was the only therapeutic choice in this situation. However, in recent years some newer agents with different mechanisms of actions have been added to the arsenal, and more are on the horizon. For a successful therapy it is of vital importance that these compounds are used judiciously and dosed appropriately. The present article reviews the pharmacokinetic properties of vancomycin, linezolid, tigecycline and daptomycin. The first major difference between these compounds is their oral bioavailability. Only linezolid can be administered orally, whereas vancomycin, daptomycin and tigecycline are limited to parenteral use. Once in the body, they show very different disposition. Daptomycin has a very small volume of distribution of 7L indicating very little tissue distribution whereas tigecycline has a very large volume of distribution of 350-500 L. Vancomycin and linezolid are in-between with volumes of distribution of approximately 30 and 50 L, close to total body water. However, studies have shown that linezolid shows better tissue penetration than vancomycin. Newer studies using microdialysis, a new technique that allows direct monitoring of unbound tissue levels, support this finding. As far as drug elimination, daptomycin and vancomycin are mainly eliminated into the urine and require dosing adjustments in renally impaired patients, whereas tigecycline is eliminated into the bile and linezolid is metabolized so that in renal patients no dosing adjustments are needed for these compounds. Although the elimination pathways are very different, the resulting half-lives of linezolid, vancomycin, and daptomycin are not greatly different and vary from 4-8 h. Tigecycline, however, has a much longer half-life of up to 1-2 days due to the slow redistribution from tissue binding sites
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