Perceiving color across scale: great and small, discrete and continuous

We generalize, to images with continuously varying colors, our previously published model for comparing color differences of spatially discrete visual fields (icons, symbols) of disparate sizes. Our model is structural, including scattering of light by the intraocular media, followed by sparse retinal cone cell sampling of each physiological color primary. We use our model to show that small subtense of less than half a degree drastically reduces the number of discriminable colors available within a color gamut. The proposed generalization predicts and explains appearance of color fields having a wide range of subtenses (from 1/8 deg to 44 deg in examples given).     

Backscatter signatures of biological aerosols in the infrared

To develop a deeper understanding of the optical signatures of both biological aerosols and potential interferents, we made field measurements of optical cross sections and compared them to model-based predictions. We measured aerosol cross sections by conducting a hard-target calibration of a light detection and ranging system (LIDAR) based on the Frequency Agile Laser (FAL). The elastic backscatter cross sections are estimated at 19 long-wave infrared (LWIR) wavelengths spanning the range from 9.23 to 10.696 μm. The theoretical modeling of the elastic backscatter cross sections is based on the measured refractive index and size distribution of the aerosols, which are used as inputs into Mie calculations. Both model calculations and experimental measurements show good agreement and also indicate the presence of spectral features based on single particle absorption in the backscatter cross sections that can be used as a basis for discrimination for both standoff and point sensors.     

Smokers and non-smokers talk about regulatory options in tobacco control

Objective

Community members are occasionally polled about tobacco control policies, but are rarely given opportunities to elaborate on their views. We examined laypeople''s conversations to understand how 11 regulatory options were supported or opposed in interactions.

Design

Qualitative design; purposive quota sampling; data collection via focus groups.

Setting

Three locations in Sydney, Australia.

Participants

63 smokers and 75 non‐smokers, men and women, from three age groups (18–24, 35–44, 55–64 years), recruited primarily via telephone.

Measurements

Semi‐structured question route; data managed in NVivo; responses compared between groups.

Results

Laypeople rejected some regulatory proposals and certain arguments about taxation and the cost of cessation treatments. Protecting children and hypothecating tobacco excise for health education and care were highly acceptable. Plain packaging, banning retail displays and youth smoking prevention received qualified support. Bans on political donations from tobacco corporations were popular in principle but considered logistically fraught. Smokers asked for better cessation assistance and were curious about cigarette ingredients. Justice was an important evaluative principle. Support was often conditional and unresolved arguments frequent. We present both sides of these conflicts and the ways in which policies were legitimised or de‐legitimised in conversation.

Conclusions

Simple measures of agreement used in polls may obscure the complexity of community responses to tobacco policy. Support was frequently present but contested; some arguments that seem self‐evident to advocates were not so to participants. The detailed understanding of laypeople''s responses provided through qualitative methods may help frame proposals and arguments to meet concerns about justice, effectiveness and feasibility.     

Self-calibrating 3D-ultrasound-based bone registration for minimally invasive orthopedic surgery

Intraoperative freehand three-dimensional (3-D) ultrasound (3D-US) has been proposed as a noninvasive method for registering bones to a preoperative computed tomography image or computer-generated bone model during computer-aided orthopedic surgery (CAOS). In this technique, an US probe is tracked by a 3-D position sensor and acts as a percutaneous device for localizing the bone surface. However, variations in the acoustic properties of soft tissue, such as the average speed of sound, can introduce significant errors in the bone depth estimated from US images, which limits registration accuracy. We describe a new self-calibrating approach to US-based bone registration that addresses this problem, and demonstrate its application within a standard registration scheme. Using realistic US image data acquired from 6 femurs and 3 pelves of intact human cadavers, and accurate Gold Standard registration transformations calculated using bone-implanted fiducial markers, we show that self-calibrating registration is significantly more accurate than a standard method, yielding an average root mean squared target registration error of 1.6 mm. We conclude that self-calibrating registration results in significant improvements in registration accuracy for CAOS applications over conventional approaches where calibration parameters of the 3D-US system remain fixed to values determined using a preoperative phantom-based calibration.     

Emerging noninvasive biochemical measures to predict cardiovascular risk

New predictors of cardiovascular events are needed to improve the accuracy of risk stratification. Such predictors should be easily measurable in the population and potentially modifiable. This review reports on new biomarkers that are closely linked to the pathogenic mechanisms underlying the progression of the atherosclerotic plaque leading to rupture and thrombosis that ultimately precipitate acute clinical events, such as stroke and myocardial infarction. These risk factors have been associated with subclinical or clinical cardiovascular disease in large populations and include markers of lipoprotein and lipid metabolism, vitamin B12 metabolism, fibrinolysis, coagulation, inflammation, infection, endothelial dysfunction, the angiotensin system, and oxidative stress. For other key processes of atherosclerosis and cardiac disease, such as apoptosis or programmed cell death, there are currently no markers that can be measured noninvasively. Atherosclerosis is a multifactorial condition and possibly only a subset of factors are the main determinants of disease in a given patient. A better definition of the cardiovascular risk profile will help to better target primary and secondary prevention. Further epidemiological studies are needed to characterize the actual predictive and clinical value of these new emerging cardiovascular biomarkers.     

Does competition enhance or inhibit motor performance: a meta-analysis

A meta-analysis was conducted on the relative impact of cooperative, competitive, and individualistic efforts on motor skills performance. Competition was divided into 3 groups: zero sum, appropriate, and unclear. The motor skills tasks were divided into means-interdependent and means-independent tasks. The dependent variables were achievement-performance, interpersonal attraction, social support, and self-esteem. A total of 64 studies met the criteria for inclusion. Effects sizes were computed, and confidence intervals were used to determine their significance. A fail-safe sample size was computed to determine how many additional studies were needed to change the significance of the results. Cooperation resulted in higher achievement for means-interdependent tasks in zero-sum competition, unclear competition, and individualistic efforts, and it promoted higher achievement for means-independent tasks for unclear competition and individualistic efforts. For all comparisons, cooperation resulted in greater interpersonal attraction, social support, and self-esteem.     

The R-type pyocin of Pseudomonas aeruginosa C is a bacteriophage tail-like particle that contains single-stranded DNA

Pseudomonas aeruginosa R-type pyocin particles have been described as bacteriocins that resemble bacteriophage tail-like structures. Because of their unusual structure, we reexamined whether they contained nucleic acids. Our data indicated that pyocin particles isolated from P. aeruginosa C (pyocin C) contain DNA. Probes generated from this DNA by the random-primer extension method hybridized to distinct bands in restriction endonuclease-digested P. aeruginosa C genomic DNA. These probes also hybridized to genomic DNA from 6 of 18 P. aeruginosa strains that produced R-type pyocins. Asymmetric PCR, complementary oligonucleotide hybridization, and electron microscopy indicated that pyocin C particles contained closed circular single-stranded DNA, approximately 4.0 kb in length. Examination of total intracellular DNA from mitomycin C-induced cultures revealed the presence of two extrachromosomal DNA molecules, a double-stranded molecule and a single-stranded molecule, which hybridized to pyocin DNA. Sequence analysis of 7,480 nucleotides of P. aeruginosa C chromosomal DNA containing the pyocin DNA indicated the presence of pyocin open reading frames with similarities to open reading frames from filamentous phages and cryptic phage elements. We did not observe any similarities to known phage structural proteins or previously characterized pseudomonal prt genes expressing R-type pyocin structural proteins. These studies demonstrate that pyocin particles from P. aeruginosa C are defective phages that contain a novel closed circular single-stranded DNA and that this DNA was derived from the chromosome of P. aeruginosa C.     

Short-term stability of NEO–PI–R personality trait scores in opioid-dependent outpatients.

The present study examined the short-term stability of personality trait scores from the Revised NEO Personality Inventory (NEO–PI-R) among 230 opioid-dependent outpatients. The NEO–PI-R is a 240-item empirically developed measure of the five-factor model of personality (Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness). Participants completed the NEO–Pl-R at admission and again approximately 19 weeks later. Results indicated fair to good stability for all NEO–PI-R factor domain scores, with coefficients ranging from .68 to .74. Stability of NEO–PI-R scores was decreased among potentially invalid response patterns but was not significantly affected by drug-positive versus drug-negative status at follow-up. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Crystal Chemistry and Stabilization in Air of Brannerite, UTi2O6

Brannerite, UTi₂O₆, can be formed only under low oxygen pressures by dry ceramic processing techniques, but the substitution of ∼0.2 and 0.3 formula units (fu) of Ca or Gd, respectively, for U allows the stabilization of the phase in air. The Ca/Gd in brannerite provides charge compensation for some U to exist in valence states >+4, as found by X-ray absorption spectroscopy of the U L _III-edge. The maximum solubilities of Ca and trivalent rare earths in the air-fired samples, 0.3 and 0.5 fu, respectively, correspond to U having an average valence of +5. Ca and Gd had maximum solubilities of 0.2 and 0.45 fu, respectively, in argon-fired samples. An absorption band at 1448 nm in both air- and Ar-fired U-brannerite doped with Ca and Gd was observed using diffuse-reflectance spectroscopy and attributed to an electronic transition of U⁵⁺. A similar band was observed in an annealed natural brannerite, which contained Ca, rare earths, and Th, although the band was present at ∼1520 nm in the unannealed, X-ray amorphous sample. In synthetic ThTi₂O₆ (thorutite, having the brannerite structure), the solubility of Ca was undetectable and that of rare earths <0.1 fu. Other ionic substitutions in synthetic brannerites involved Hf, Pu, La, and Y for U, (Gd + Nb) for U + Ti, and Fe in the Ti site.