Search results for "void"
showing 10 items of 435 documents
3D Conformations of Thick Synthetic Polymer Chains Observed by Cryogenic Electron Microscopy.
2019
The backbone conformations of individual, unperturbed synthetic macromolecules have so far not been observed directly in spite of their fundamental importance to polymer physics. Here we report the dilute solution conformations of two types of linear dendronized polymers, obtained by cryogenic transmission electron stereography and tomography. The three-dimensional trajectories show that the wormlike chain model fails to adequately describe the scaling of these thick macromolecules already beyond a few nanometers in chain length, in spite of large apparent persistence lengths and long before a signature of self-avoidance appears. This insight is essential for understanding the limitations o…
Structures, properties and miscibility behaviour of liquid crystalline polycatenar tetrone derivatives
1995
Abstract The tetrones represent an interesting new mesogenic building block. The results of this study show that they can be incorporated into a variety of mesophases. A smectic phase was observed in the polycatenar compound with four terminal chains as expected. The phase exhibits a tilted structure (Sc phase) to prevent void formation. The compound with six pendant chains forms a columnar phase. In spite of their structural similarity, the tetrones studied tended not to be completely miscible. However, complete miscibility with a semi-discoid phenylhydrazone was observed. When this hydrazone, which forms a columnar ‘Dho phase’, was mixed with tetrone which forms a columnar ‘Dhd phase’ a c…
Exposing ecological and economic costs of the research-implementation gap and compromises in decision making
2018
The frequently discussed gap between conservation science and practice is manifest in the gap between spatial conservation prioritization plans and their implementation. We analyzed the research-implementation gap of one zoning case by comparing results of a spatial prioritization analysis aimed at avoiding ecological impact of peat mining in a regional zoning process with the final zoning plan. We examined the relatively complex planning process to determine the gaps among research, zoning, and decision making. We quantified the ecological costs of the differing trade-offs between ecological and socioeconomic factors included in the different zoning suggestions by comparing the landscape-l…
Protective coloration of European vipers throughout the predation sequence
2020
Antipredator adaptations in the form of animal coloration are common and often multifunctional. European vipers (genus Vipera) have a characteristic dorsal zigzag pattern, which has been shown to serve as a warning signal to potential predators. At the same time, it has been suggested to decrease detection risk, and to cause a motion dazzle or flicker-fusion effect during movement. We tested these hypotheses by asking whether (1) the zigzag pattern decreases detection risk and (2) the detection is dependent on the base coloration (grey or brown) or the snake's posture (coiled, basking form or S-shaped, active form). Additionally, (3) we measured the fleeing speed of adders, Vipera berus, an…
Online Expression, Personal Cybersecurity Costs, and the Specter of Cybercrime
2020
The internet is used increasingly as a platform both for free expression and e-commerce. The internet has unique security and privacy risks. Such risks include the threat of criminal cyberattacks, including hacking and doxing. Internet users have a variety of attitudes towards the security and privacy risks involved with using the internet and distinct concerns and behaviors with regard to expressing themselves online. In order to mitigate the security and privacy risks of the internet, some internet users spend valuable time thinking about and configuring the security settings of their devices. They may also have different attitudes towards personal spending of money for cybersecurity prod…
Synthesis and self-assembly of a PEGylated-graphene aerogel
2016
Abstract In the frame of this work, we present, for the first time, the synthesis and self-assembly of an aerogel built by graphene oxide-polyethylene glycol. The synthetic route involves at first the coupling of GO with an amino-terminated polyethylene glycol sample by carbodiimide in aqueous environment, and the subsequent conversion of the hydrogel achieved into an aerogel via freeze-drying. The 3D PEGylated graphene-based aerogel, characterized by spectroscopic, morphological, structural and mechanical analyses, displays an ultralight and highly porous (99.7%) network and possesses high mechanical properties together with a good biocompatibility.
Psychological and behavioural factors of unintentional doping: A preliminary systematic review
2018
In some cases, doping in sport is an intentional goal-directed behaviour, but research suggests that it might also occur accidentally when athletes inadvertently or unintentionally consume banned performance-enhancing drugs via food, supplements, or medication. Because research into the psychological factors of unintentional doping is still emerging, this paper aims to conduct a preliminary systematic review of all the existing literature concerning the psychology of unintentional doping in sport. The systematic review was carried out via an extensive search of Medline, PsycINFO, PsycTESTS, PsycARTICLES, and Web of Science, and reports from World Anti-Doping Agency. Among the 2110 articles …
L'optimisation fusion - confusion : une synthèse privilégiée du droit et du chiffre
2010
It is not always easy to dissociate, in the settlement problems, tax and accounting, the main thing and the ac cessory. Generally, mergers are in this case, simplified mergers and universal transmissions, too. When professionals want, in this field, to optimize integrated, legal choices - tax - accounting, it is often obliged to treat the problem, without assistanc e. This autonomy look that this subject is at the crossroads of several disciplines and it is necessary to compose, without really opposing them. The field of mergers and confusion is a good synthesis of the link Law - management. The company which wishes to absorb its 100 % subsidiary can choose between simplified fusion and dis…
Replication of the association between CHRNA4 rs1044396 and harm avoidance in a large population-based sample.
2015
Harm avoidance is a personality trait characterized by excessive worrying and fear of uncertainty, which has repeatedly been related to anxiety disorders. Converging lines of research in rodents and humans point towards an involvement of the nicotinic cholinergic system in the modulation of anxiety. Most notably, the rs1044396 polymorphism in the CHRNA4 gene, which codes for the α4 subunit of the nicotinic acetylcholine receptor, has been linked to negative emotionality traits including harm avoidance in a recent study. Against this background, we investigated the association between harm avoidance and the rs1044396 polymorphism using data from N=1673 healthy subjects, which were collected …
Data from: Predators’ consumption of unpalatable prey does not vary as a function of bitter taste perception
2019
Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is therefore assumed to be important when predators are learning about prey defenses. However, it is not known how individuals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among individuals, ranging from chloroquine concentrations of 0.01 mmol/l to 8 mmol/l. W…