Chemical trail marking and following by caterpillars ofMalacosoma neustria

Chemical trail marking and following by gregarious caterpillars,Malacosoma neustria L. (Lepidoptera: Lasiocampidae), was studied in the laboratory. As in other species ofMalacosoma, larvae deposit a trail pheromone from a sternal secretory site when searching the host for food. Larvae in the vanguard of foraging columns establish chemical trails as they explore new territory. Marking behavior diminishes as successive unfed foragers utilize the trail. These exploratory trails are subsequently overmarked by fed larvae returning to the tent. Other foragers follow the trails of fed larvae in preference to trails of unfed larvae. Thus, like the eastern tent caterpillar,M. americanum, successful foragers ofM. neustria recruit colony-mates to feeding sites. The chemical activity of both recruitment and exploratory trails degrades slowly, suggesting that the trail pheromone ofM. neustria is a nonvolatile substance. Caterpillars ofM. neustria readily follow the nonvolatile trail pheromone which has been identified fromM. americanum, 5-cholestane-3,24-dione.     

Effects of instructions on measures of state and trait anxiety in flight students.

Administered the State-Trait Anxiety Inventory twice to 134 flight students during their routine entrance aviation physical examination. Ss were lower in trait anxiety and higher in state anxiety than a group of 253 previously tested male college students. However, with an induced anxiety act, both state and trait anxiety scores were significantly lower than the scores obtained during the initial administration of the test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of strategic self-presentation on subsequent self-esteem.

Three experiments (88 male and 36 female undergraduates) explored the effects of self-enhancement or self-deprecation on the actor's self-esteem as measured in a separate context. In Exp I, Ss were influenced, by observing others in a screening interview, to emulate their self-enhancing or self-deprecating behavior when they themselves were interviewed. This carried over and was reflected in their subsequent self-esteem. In Exp II, this carry-over effect was replicated in a setting in which S was interviewed while playing the role of a job candidate. In Exp III, Ss instructed to be self-enhancing in an interview subsequently showed elevated self esteem (unless their interview behavior was prescribed by the experimenter and thus not self-referring). Ss instructed to be self-deprecating subsequently showed lowered self-esteem if they had been given a clear choice as to whether to engage in the interview. It is concluded that self-perception theory can account for self-enhancing carry-over, whereas dissonance theory offers a more appropriate explanation for the carry-over or internalization of self-deprecating actions. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An augmented reality system for patient-specific guidance of cardiac catheter ablation procedures

We present a system to assist in the treatment of cardiac arrhythmias by catheter ablation. A patient-specific three-dimensional (3-D) anatomical model, constructed from magnetic resonance images, is merged with fluoroscopic images in an augmented reality environment that enables the transfer of electrocardiography (ECG) measurements and cardiac activation times onto the model. Accurate mapping is realized through the combination of: a new calibration technique, adapted to catheter guided treatments; a visual matching registration technique, allowing the electrophysiologist to align the model with contrast-enhanced images; and the use of virtual catheters, which enable the annotation of multiple ECG measurements on the model. These annotations can be visualized by color coding on the patient model. We provide an accuracy analysis of each of these components independently. Based on simulation and experiments, we determined a segmentation error of 0.6 mm, a calibration error in the order of 1 mm and a target registration error of 1.04 +/- 0.45 mm. The system provides a 3-D visualization of the cardiac activation pattern which may facilitate and improve diagnosis and treatment of the arrhytmia. Because of its low cost and similar advantages we believe our approach can compete with existing commercial solutions, which rely on dedicated hardware and costly catheters. We provide qualitative results of the first clinical use of the system in 11 ablation procedures.     

Experimental and simulated angular profiles of fluorescence and diffuse reflectance emission from turbid media

Given the wavelength dependence of sample optical properties and the selective sampling of surface emission angles by noncontact imaging systems, differences in angular profiles due to excitation angle and optical properties can distort relative emission intensities acquired at different wavelengths. To investigate this potentiality, angular profiles of diffuse reflectance and fluorescence emission from turbid media were evaluated experimentally and by Monte Carlo simulation for a range of incident excitation angles and sample optical properties. For emission collected within the limits of a semi-infinite excitation region, normalized angular emission profiles are symmetric, roughly Lambertian, and only weakly dependent on sample optical properties for fluorescence at all excitation angles and for diffuse reflectance at small excitation angles relative to the surface normal. Fluorescence and diffuse reflectance within the emission plane orthogonal to the oblique component of the excitation also possess this symmetric form. Diffuse reflectance within the incidence plane is biased away from the excitation source for large excitation angles. The degree of bias depends on the scattering anisotropy and albedo of the sample and results from the correlation between photon directions upon entrance and emission. Given the strong dependence of the diffuse reflectance angular emission profile shape on incident excitation angle and sample optical properties, excitation and collection geometry has the potential to induce distortions within diffuse reflectance spectra unrelated to tissue characteristics.     

Detection of repolarization alternans with an implantable cardioverter defibrillator lead in a porcine model

Mechanistic links have been suggested between repolarization alternans (RPA) and the onset of ventricular tachycardia (VT) and/or fibrillation. Endocardial detection of RPA may, therefore, be an important step in future device-based treatments of arrhythmias. Here, we investigate if RPA could be detected during acute ischemia using an implantable cardioverter defibrillator (ICD) lead (tip to distal coil) located in the right ventricular apex. In 18 pigs, the right coronary (n = 10) or left anterior descending coronary (n = 8) artery was occluded for 10 min using a balloon catheter, followed by reperfusion for 30 min, and re-occlusion for 30 min. RPA magnitude, computed using the modified moving average (MMA) method, showed a sharp increase in all 18 animals, from a mean baseline level of 1.9 +/- 1.3 mV to 3.0 +/- 1.3 mV during first occlusion (p < 0.001). RPA magnitude showed a prominent increase in 10 animals during re-occlusion, from a mean baseline level of 1.7 +/- 1.0 mV to 3.3 +/- 1.5 mV (p < 0.001). The protocol was terminated during the first two stages of occlusion and reperfusion for the remaining 8 animals due to the occurrence of ventricular fibrillation (VF). These results confirm that RPA increases under ischemic conditions and that it is possible to detect and track RPA dynamics with an ICD lead that is positioned in a clinically realistic location. Such an approach may be useful in formulating improved arrhythmia detection and control algorithms.     

Spatio-spectral filters for improving the classification of single trial EEG

Data recorded in electroencephalogram (EEG)-based brain-computer interface experiments is generally very noisy, non-stationary, and contaminated with artifacts that can deteriorate discrimination/classification methods. In this paper, we extend the common spatial pattern (CSP) algorithm with the aim to alleviate these adverse effects. In particular, we suggest an extension of CSP to the state space, which utilizes the method of time delay embedding. As we will show, this allows for individually tuned frequency filters at each electrode position and, thus, yields an improved and more robust machine learning procedure. The advantages of the proposed method over the original CSP method are verified in terms of an improved information transfer rate (bits per trial) on a set of EEG-recordings from experiments of imagined limb movements.     

Multidimensional high-throughput screening of displacers

A multidimensional, batch high-throughput screening (MD-HTS) protocol was developed to investigate the effects of various parameters on the selectivity of ion-exchange protein displacement systems. A variety of molecules were screened, and the results were employed to provided insights into the influence of displacer chemistry and concentration, resin chemistry, and mobile-phase salt counterion on the efficacy and selectivity of these nonlinear chromatographic systems. These results open up the possibility of tailoring the selectivity of displacement separations by choosing appropriate combinations of operating conditions using the MD-HTS technique. The screens were also employed for the identification of displacers and conditions for the separation of a challenging protein mixture by selective displacement chromatography. Column displacements were carried out with potential lead compounds identified from the MD-HTS screens, and the results confirmed that selective displacement could indeed be achieved for this model mixture. Furthermore, the results indicated that this approach is particularly useful when the order of elution is not changed, but the inherent selectivity is increased in the presence of the displacer. The results presented in this paper demonstrate the utility of the MD-HTS technique for rapid method development in protein ion-exchange displacement chromatography.     

Modelling of composite neutron scintillators

Composite neutron scintillators consisting of neutron-insensitive fluorescent dopant particles (e.g. ZnS:Ag) embedded in a matrix material containing isotopes with high neutron cross sections that emit energetic charged particles (e.g. 6Li) are a popular method for neutron detection in a variety of applications. The size and volume doping fraction of the fluorescent dopant particles and the densities of both dopant particles and the matrix material determine the characteristics of the pulse-height spectrum of emitted light and the probability that capture of a neutron will result in scintillation. In this work, we characterise the effects of these parameters for ZnS:Ag particles in a lithiated glass matrix using a Monte Carlo simulation of composite neutron detectors that we have constructed.     

Rapid forensic analysis and identification of ''lilac'' architectural finishes using Raman spectroscopy

The potential of Raman spectroscopy to discriminate between architectural finishes (household paint) has been investigated using a test set of 51 'lilac' paints and three different excitation wavelengths. The spectra obtained with visible excitation typically displayed a series of intense Raman bands on a featureless fluorescence background but the spectra of all the paints studied had essentially identical bands. With 785 nm excitation, although the same bands that dominated the 514 nm spectra were still observed, other bands with comparable intensity also appeared. The two strongest scattering constituents were identified as a dioxazine dye, Violet 23 and beta-Cu(phthalocyanine). A scatter plot of the intensities of marker bands for these constituents (normalized to the strong rutile bands that were always present) showed that, despite the fact that the sample set spanned a wide range of rutile : dioxazine dye : phthalo- cyanine ratios, many of the samples had very similar ratios and could not be discriminated. However, all the samples (even those with similar relative proportions of the main constituents) could be discriminated on the basis of their minor constituents, either by manually measuring band intensities or through the creation and searching of spectral libraries.