Responses of soil microbial communities to weak electric fields

Electrokinetically stimulated bioremediation of soils (electro-bioremediation) requires that the application of weak electric fields has no negative effect on the contaminant degrading microbial communities. This study evaluated the hypothesis that weak direct electric current (DC) fields per se do not negatively influence the physiology and composition of soil microbial communities given that secondary electrokinetic phenomena such as soil pH changes and temperatures are minimized. Mildly buffered, water-saturated laboratory mesocosms with agricultural soil were subjected for 34 days to a constant electric field (X = 1.4 V cm^− 1; J ≈ 1.0 mA cm^− 2) and the spatiotemporal changes of soil microbial communities assessed by fingerprints of phospholipids fatty acids (PLFA) and terminal restriction fragment length polymorphisms (T-RFLP) of bacterial 16S rRNA genes. DC-induced electrolysis of the pore water led to pH changes (< 1.5 pH units) in the immediate vicinity of the electrodes and concomitant distinct soil microbial community changes. By contrast, DC-treated bulk soil distant to the electrodes showed no pH changes and developed similar PLFA- and T-RFLP-fingerprints as control soil in the absence of DC. Our data suggest that the presence of an electric field, if suitably applied, will not influence the composition and physiology of soil microbial communities and hence not affect their potential to biodegrade contaminants.     

Propane conversion in the presence of iron- and manganese-promoted sulfated zirconia: evidence of Olah carbocation chemistry

Iron- and manganese-promoted sulfated zirconia was tested for conversion of propane at 1 bar, 200, 250, and 300°C, and propane partial pressures of 0.01, 0.025, and 0.05 bar. Propane was converted to pentanes, butanes, propene, ethane, ethene, and methane at 250°C, but the conversions were low, for example, being only a fraction of a percent at a space velocity of 9.1 × 10^–7 mol/(g s) and a propane partial pressure of 0.05 bar. Carbonaceous deposits formed rapidly. At 250°C, the number of propane molecules converted to gas-phase products was only about 1 per sulfate group after 16 days of operation in a continuous flow reactor. The observation of butanes and pentanes as products is consistent with Olah superacid solution chemistry, whereby propane is first protonated by a very strong acid to form a carbonium ion. The carbonium ion then decomposes into methane and an ethyl cation, which undergoes secondary reactions with propane to form higher-molecular-weight alkanes.     

"Dissociating Local and Global Levels of Perceptuo-Motor Control in Masked Priming": Correction to Schlaghecken et al. (2006).

Reports an error in "Dissociating Local and Global Levels of Perceptuo-Motor Control in Masked Priming" by Friederike Schlaghecken, Howard Bowman and Martin Eimer (Journal of Experimental Psychology: Human Perception and Performance, 2006[Jun], Vol 32[3], 618-632). Figure 5 was inadvertently duplicated in the production process and was incorrectly substituted in place of the original Figure 6 submitted by the authors. The correct figure and caption that should have appeared for Figure 6 are listed in the erratum. (The following abstract of the original article appeared in record 2006-08586-008.) Masked prime stimuli presented near the threshold of conscious awareness affect responses to subsequent targets. The direction of these priming effects depends on the interval between masked prime and target. With short intervals, benefits for compatible trials (primes and targets mapped to the same response) and costs for incompatible trials are observed. This pattern reverses with longer intervals. We argue (a) that these effects reflect the initial activation and subsequent self-inhibition of the primed response, and the corresponding inhibition and subsequent disinhibition of the nonprimed response, and (b) that they are generated at dissociable local (within response channels) and global (between channels) levels of motor control. In two experiments, global-level priming effects were modulated by changing the number of response alternatives, whereas local-level effects remained unaffected. These experiments suggest that low-level motor control mechanisms can be successfully decomposed into separable subcomponents, operating at different levels within the motor system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

THE ROLE OF HIERARCHY LEVELS IN VOCAL IMITATIONS OF SONGBIRDS

The singing of adult birds shows a clear hierarchical organization and, due to its development through vocal imitation of sound patterns, makes an excellent biological model to examine the variables that influence the imitation of patterns on different hierarchy levels, e.g., songs and elements composing the songs. We studied such variables in the nightingale (Luscinia megarhynchos), i.e., a species that in the wild uses a large repertoire of songs. Subjects were raised in the lab and tutored by presenting them with a serial learning task, here a sequence of differently patterned songs. Analyses of singing, which the trained subjects performed at the end of their vocal ontogeny, allowed us to uncover hierarchy-related accomplishments and also specific constraints in learning by imitation. Our results showed that an imitation of elements and element sequences reflected a kind of "gestalt" learning, which finally became visible in the form of specific song patterns. An imitation of song sequences, on the other hand, reflected a kind of "list" learning, which finally emerged into the formation of specific subrepertoires of song types. The structure of such subrepertoires mirrored the serial order of imitated songs but allowed, nevertheless, a serially flexible retrieval of single types of songs. These findings contribute to a better understanding of relationships between signal imitation and signal use during vocal interactions among songbirds.     

Nanocellulose as a natural source for groundbreaking applications in materials science: Today’s state

Nanocelluloses are natural materials with at least one dimension in the nano-scale. They combine important cellulose properties with the features of nanomaterials and open new horizons for materials science and its applications. The field of nanocellulose materials is subdivided into three domains: biotechnologically produced bacterial nanocellulose hydrogels, mechanically delaminated cellulose nanofibers, and hydrolytically extracted cellulose nanocrystals. This review article describes today’s state regarding the production, structural details, physicochemical properties, and innovative applications of these nanocelluloses. Promising technical applications including gels/foams, thickeners/stabilizers as well as reinforcing agents have been proposed and research from last five years indicates new potential for groundbreaking innovations in the areas of cosmetic products, wound dressings, drug carriers, medical implants, tissue engineering, food and composites. The current state of worldwide commercialization and the challenge of reducing nanocellulose production costs are also discussed.     

Is There a Visual Dominance in Political Communication? How Verbal,Visual, and Vocal Communication Shape Viewers' Impressions of Political Candidates

On the basis of a televised debate in the 2005 German national election, this study compares the influence of verbal, visual, and vocal communication on viewers' immediate impressions of political candidates by using an innovative research design. A second‐by‐second content analysis of 17 verbal, visual, and vocal message elements is combined with a second‐by‐second analysis of viewers' immediate impressions using continuous response measurement (CRM). Findings show that viewers' immediate impressions are mainly influenced by verbal communication, especially the issues discussed and the argumentative structure used. In contrast to that, the effect of nonverbal communication is far smaller. The causes and implications of these findings are discussed.