Influence of droplet cloud water content on the polarization characteristics of the double scattering lidar signal

The paper discusses results of a numerical modeling of distribution of the intensity of double scattering lidar signal in the detection plane at different states of polarization of the probe radiation. We have found that the ratio of the degrees of polarization of the of the double scattering signal when probed with circularly and linearly polarized radiation is independent of the angle of view lidar receiving system. Shown that the dependence of this ratio on of the water content of clouds is linear. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Isoprenoids enhance the stability of fatty acid membranes at the emergence of life potentially leading to an early lipid divide

Two key problems concern cell membranes during the emergence and early evolution of life: what was their initial composition, and why did the membranes of archaea and bacteria diverge? The composition of the first cell membranes could shed light on the most likely environment for the emergence of life. The opposing stereochemistry of modern lipid glycerol-phosphate headgroups in bacteria and archaea suggests that early membranes were composed of single chain amphiphiles, perhaps both fatty acids and isoprenoids. We investigated the effect of adding isoprenoids to fatty acid membranes using a combination of UV–visible spectroscopy, confocal microscopy and transmission electron microscopy. We tested the stability of these membranes across a pH range and under different concentrations of ionic species relevant to oceanic hydrothermal environments, including Na2+, Cl−, Mg2+, Ca2+, HCO−3, Fe3+, Fe2+ and S2−. We also tested the assembly of vesicles in the presence of Fe particles and FeS precipitates. We found that isoprenoids enhance the stability of membranes in the presence of salts but require 30-fold higher concentrations for membrane formation. Intriguingly, isoprenoids strongly inhibit the tendency of vesicles to aggregate together in the presence of either Fe particles or FeS precipitates. These striking physical differences in the stability and aggregation of protocells may have shaped the divergence of bacteria and archaea in early hydrothermal environments

Simultaneous EEG and fMRI: T1-based evaluation of heating in a gel phantom at 3 Tesla

EEG electrodes and leads, comparable to metallic implants, can lead to heating of tissue when used in an MRI scanner. Simultaneous EEG and fMRI experiments are frequently carried out at 3 T or higher fields. High field strength, and thus high-energy RF pulses, added to complex EEG lead configuration increases the risk of severe localized heating, or hot spots. Unlike the skin, the brain lacks thermoreceptors, and the subject might not report anything unusual during the scan although hot spots may occur. In simultaneous EEG and fMRI experiments, the temperature at individual electrode sites can be monitored using optic fibre temperature probes. To complement the isolated surface temperature readings, we aimed to map the whole temperature distribution within a phantom. An EEG-equipped gel phantom was imaged using a T1-weighted sequence before and after running a high-energy MR sequence at 3 T. Changes in T1 intensity profile would indicate a relative temperature increase. In our setting, hot spots were not detected in the relative temperature maps of the phantom. Optic fibre temperature probes at selected electrode sites indicated small temperature increases depending on the MR sequence used. The phantom core temperature remained unchanged. RF energy distribution can vary with electrode configurations and MRI scanners. We suggest that EEG equipments should be tested for safety reasons. The MRI thermometry –inspired relative T1 intensity method provides an easy way to test possible heating within a phantom

PAUSED for thought? Using verbal protocol analysis to understand the situational and temporal cues in the decision-making of residential burglars

Using verbal protocol analysis (VPA) alongside semi-structured interviews, this research aimed to explicate the situational dynamics that inform the decision-making and target selection of residential burglars. Focusing on the VPA method, novel to criminological research, the paper considers the contribution of this empirical approach for studying the decision-making of offenders in situ. The findings reveal a series of cues, encapsulated in the ‘PAUSED’ model, that are drawn upon by residential burglars to assess the suitability of a target; determining whether it is profitable, accessible, uninterruptible, surveillable, escapable and/or dishonourable. The PAUSED model is unpacked to articulate a collection of visual stimuli that serve to disrupt and suspend the otherwise rapid flow of target appraisal. Discussion of the strengths and limitations of the VPA method, and how it can compliment other approaches to understanding the decision-making of residential burglars, is provided

Inhibitory Selection Mechanisms in Clinically Healthy Older and Younger Adults

OBJECTIVE: Declines in working memory are a ubiquitous finding within the cognitive-aging literature. A unitary inhibitory selection mechanism that serves to guide attention toward task-relevant information and resolve interference from task-irrelevant information has been proposed to underlie such deficits. However, inhibition can occur at multiple time points in the memory-processing stream. Here, we tested whether the time point at which inhibition occurs in the memory-processing stream affects age-related memory decline. METHOD: Clinically healthy younger (n = 23) and older (n = 22) adults performed two similar item-recognition working memory tasks. In one task, participants received an instruction cue telling them which words to attend to followed by a memory set, promoting perceptual inhibition at the time of encoding. In the other task, participants received the instruction cue after they received the memory set, fostering inhibition of items already in memory. RESULTS: We found that older and younger adults differed in their ability to inhibit items both during encoding and when items had to be inhibited in memory but that these age differences were exaggerated when irrelevant information had to be inhibited from memory. These results provide insights into the mechanisms that support cognitive changes to memory processes in healthy aging

CALCIUM RESPONSES IN FIBROBLASTS FROM ASYMPTOMATIC MEMBERS OF ALZHEIMER'S DISEASE FAMILIES

Abstract We have previously identified alterations of K + channel function, IP 3 -mediated calcium release, and Cp20 (a memory-associated GTP binding protein) in fibroblasts from Alzheimer's disease (AD) patients vs controls. Some of these alterations can be integrated into an index that distinguishes AD patients from controls with both high specificity and high sensitivity. We report here that alterations in IP 3 -mediated calcium responses are present in a large proportion of AD family members (i.e., individuals at high risk) before clinical symptoms of Alzheimer's disease are present. This was not the case if such members later "escaped" AD symptoms. This preclinical calcium signal correlate of later AD does not reflect, however, the presence of the PS1 familial AD gene

Development of reverse-transcription PCR techniques to analyse the density and sex ratio of gametocytes in genetically diverse Plasmodium chabaudi infections

We have developed cross-genotype and genotype-specific quantitative reverse-transcription PCR (qRT-PCR) assays to detect and quantify the number of parasites, transmission stages (gametocytes) and male gametocytes in blood stage Plasmodium chabaudi infections. Our cross-genotype assays are reliable, repeatable and generate counts that correlate strongly (R(2)s > 90%) with counts expected from blood smears. Our genotype-specific assays can distinguish and quantify different stages of genetically distinct parasite clones (genotypes) in mixed infections and are as sensitive as our cross-genotype assays. Using these assays we show that gametocyte density and gametocyte sex ratios vary during infections for two genetically distinct parasite lines (genotypes) and present the first data to reveal how sex ratio is affected when each genotype experiences competition in mixed-genotype infections. Successful infection of mosquito vectors depends on both gametocyte density and their sex ratio and we discuss the implications of competition in genetically diverse infections for transmission success