What Does a Pigeon (Columba livia) Brain Look Like During Homing? Selective Examination of ZENK Expression.

Lesion studies have shown that the avian hippocampus plays a crucial role in homing pigeon (Columba livia) navigation. Using the expression of the immediate early gene protein ZENK in intact pigeons, the authors found regional variation in hippocampal activation as a consequence of homing and, necessarily, the behavior and internal states that accompany it. Specifically, pigeons that homed displayed a significant increase in the number of ZENK-labeled cells in the lateral hippocampal formation compared with pigeons that did not home, whereas no difference was seen in the medial hippocampus. Significant changes in ZENK expression were also found in the medial striatum, which resembles the mammalian ventral striatum. The results identify portions of the hippocampal formation and the medial striatum as sites of plasticity associated with homing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The JDTDOA algorithm applied to signal recovery: a performance analysis

This article suggests a novel method to retrieve a narrowband signal sent in a multipath environment with a delay spread considering ISI between symbols. The proposed method does not require any preamble nor known signal. Using the joint direction and time delay of arrivals estimation algorithm developed in prior work, the directions and time delays of arrival in the multipath channel are jointly estimated and associated while keeping a low computational cost. In this process, a MVDR beamformed copy of each arriving signal is created. The quality of these “pseudo copies” is evaluated and compared to the original direct and reflected signals in this work. Another beamforming method, the Moore–Penrose pseudoinverse, with better retrieval of the direct and reflected signals is also proposed. Using a simple delay-and-sum operation on the previously beamformed copies, it is possible to substantially improve the the system’s performance in terms of bit error rate. An approach using oversampling on the array antenna is introduced to improve performance. Numerical simulations are discussed to support theory.     

Freeze-Dried Fennel Oleoresin Products Formed by Biopolymers: Storage Stability and Characterization

In this work, fennel oleoresin (FO) was encapsulated through freeze drying of the so produced emulsions within different edible biopolymeric carriers. Specifically, modified starch, maltodextrin, chitosan, and gum arabic were used as carriers both individually and in blends (binary and ternary ones). The freeze-dried FO products were characterized in terms of structure (X-ray diffraction (XRD) analysis), whereas their stability was studied by means of sorption isotherm analysis under various a _w. Moreover, the formation of complexes was evaluated through Fourier transform infrared spectroscopy (FTIR) technique and ζ-potential analysis. The verification of the encapsulation process was also conducted by applying FTIR technique. Results showed that the final products presented an amorphous character, whereas the sorption isotherms could be described adequately by the Guggenheim-Anderson-de Boer (GAB) model. FTIR technique proved to be effective to confirm both the formation of complexes and the presence of FO into the studied carriers, verifying thus the success of the process.     

Detection and Quantification of Free Glycerol in Virgin Olive Oil by <Superscript>31</Superscript>P-NMR Spectroscopy

³¹P-Nuclear magnetic resonance (NMR) spectroscopy was employed to detect and quantify free glycerol in virgin olive oils originating from various regions of Greece. This analytical method was based on the derivatization of the hydroxyl groups of glycerol with the tagging reagent 2-chloro-4,4,5,5-tetramethyldioxaphospholane, and identification of the phosphitylated compound on the basis of ³¹P chemical shifts. Quantification of glycerol in olive oils was accomplished by integration of the appropriate signals in the ³¹P NMR spectrum and the use of the phosphitylated cyclohexanol as internal standard. A linear correlation was observed between the glycerol content and 1,3-diacylglycerols and free acidity indicating that glycerol is the final product of the partial hydrolysis of triacylglycerols.     

Finite difference transmission line model for the design of safe multi-section cables in MRI

Magnetic Resonance Materials in Physics, Biology and Medicine - To show the relevance of a simple finite difference transmission line model to help design safe implanted cables in 1.5T MRI’s...     

Limitation of the Coalescence of Evolutive Droplets by the Use of Copolymers in a Thermoplastic/Thermoset Blend

Summary: Polystyrene (PS)/epoxy‐amine (DGEBA‐MDEA) is a thermoplastic/thermoset precursor blend which is miscible at high temperature (177 °C), and which phase separates under the polymerization of the epoxy‐amine system. Previous studies have shown that the morphology of this blend polymerized under shear is coarse and irregular because the dispersed epoxy‐amine domains coalesce before they gel. Several styrene‐methyl methacrylate and a styrene‐butadiene‐styrene block copolymers have been added to the PS/DGEBA‐MDEA 60/40 blend in order to limit the coalescence and thus obtain a finer morphology. Two of the copolymers used were reactive either with the epoxy or with the amine. It was shown that the addition of 15 wt.‐% of non reactive copolymer had a positive but limited effect on the size of the final epoxy‐amine particles. The copolymer remained at the interface at the early stages of the polymerization. However, it was pulled out by the shear forces around the gel point of the epoxy domains. Most of the non reactive copolymer was present in the shape of micelles at the end of the process. On the other hand, the reactive copolymers were able to establish covalent bonds with the epoxy‐amine drops and hence were not extracted at all. Consequently they allowed the decrease the size of the particles by a factor of 15. Despite this, the observation of the morphology at different stages of the polymerization has revealed that the copolymer moved at the interface of the epoxy domains during the collision of two droplets. The movements of fluids into the epoxy domains pushed the copolymer out of the inter‐droplet zone so that it could not prevent the drainage of the liquid film between the droplets and consequently their coalescence.

TEM showing that the layer of copolymer (in dark grey) has moved along the interface of epoxy‐amine drops during their successful collision in a polystyrene‐rich matrix.     

Comparison of nine common coffee extraction methods: instrumental and sensory analysis

The preparation of a cup of coffee may vary between countries, cultures and individuals. Here, an analysis of nine different extraction methods is presented regarding analytical and sensory aspects for four espressi and five lunghi. This comprised espresso and lungo from a semi-automatic coffee machine, espresso and lungo from a fully automatic coffee machine, espresso from a single-serve capsule system, mocha made with a percolator, lungo prepared with French Press extraction, filter coffee and lungo extracted with a Bayreuth coffee machine. Analytical measurements included headspace analysis with HS SPME GC/MS, acidity (pH), titratable acidity, content of fatty acids, total solids, refractive indices (expressed in °Brix), caffeine and chlorogenic acids content with HPLC. Sensory analysis included visual, aroma, flavor and textural attributes as well as aftersensation. The technical differences in the extraction methods led to a higher concentration of the respective quantities in the espressi than in the lunghi. Regarding the contents per cup of coffee, the lunghi generally had a higher content than the espressi. The extraction efficiency of the respective compounds was mainly driven by their solubility in water. A higher amount of water, as in the extraction of a lungo, generally led to higher extraction efficiency. Comparing analytical data with sensory profiles, the following positive correlations were found total solids ? texture/body, headspace intensity ? aroma intensity, concentrations of caffeine/chlorogenic acids ? bitterness and astringency.     

Aging and implementation of encoding strategies in the generation of rhymes: The role of executive functions.

This experiment examines whether the age-related decrease in the generation effect of rhymes is mediated by executive functioning. Young and elderly adults read and generated pairs of rhyming words for subsequent recall. Participants were also administered neuropsychological tests (executive and mnemonic functions). Results showed that elderly adults performed less well on the neuropsychological tests and benefited less than the younger participants from the generation effect. Hierarchical regression analyses revealed that the executive functions composite score was correlated with the generation effect and that it accounted for a large proportion of the age-related variance of the size of this measure. This finding supports the view that the age-related decrement in strategic encoding implementation is due to a decrease of executive functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)