Superballistic electron flow through a point contact in a Ga[Al]As heterostructure

We measure electronic transport through point contacts in the high-mobility electron gas in a Ga[Al]As heterostructure at different temperatures and bulk electron densities. The conductance through all point contacts increases with increasing temperature in a temperature window around $T \sim 10 K$ for all investigated electron densities and point contact widths. For high electron densities this conductance exceeds the fundamental ballistic limit (Sharvin limit). These observations are in agreement with a viscous electron transport model and previous experiments in graphene.Comment: 5 pages, 2 figure

Self-assembly in solution of a reversible comb-shaped supramolecular polymer

We report a single step synthesis of a polyisobutene with a bis-urea moiety in the middle of the chain. In low polarity solvents, this polymer self-assembles by hydrogen bonding to form a combshaped polymer with a central hydrogen bonded backbone and polyisobutene arms. The comb backbone can be reversibly broken, and consequently, its length can be tuned by changing the solvent, the concentration or the temperature. Moreover, we have proved that the bulkiness of the side-chains have a strong influence on both the self-assembly pattern and the length of the backbone. Finally, the density of arms can be reduced, by simply mixing with a low molar mass bis-urea

Hybrid cloud computing architecture based on open source technology

The advance of technologies such as distributed computing, Internetand grid computing, have enabled Cloud Computing to become part of a new model of computing and business. Cloud Computing is transforming the traditional ways in which companies use and acquire Information Technology (IT) resources. After an initial boom in Public Cloud, companies begun to mount hybrid Clouds that offer the advantages of Cloud Computing in addition to the privacy of data they consider strategic. A hybrid Cloud solution allows the integration of both systems. Leading companies in cloud solutions have understood this evolution and begun to offer hybrid solutions. Moreover, many of these companies are taking the next step by offering solutions based on open source standards that allow a high degree of interoperability and portability

Rabdomiossarcoma de vesícula urinária em cão da Serra da Estrela adulto jovem. Relato de caso

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Promoting dental care to children using traditional and interactive media following threat appeals

In recent years, computer games have become an important part of children’s lives. Gaming is not only one of their favorite pastime activities, but games are also increasingly used by marketers in an attempt to influence children’s purchase behavior. Today, almost every food and beverage brand targeting children has an advergame on its website. Advergames are “computer games specifically created to function as advertisements to promote brands”, containing brand identifiers such as logos and brand characters (Kretchmer, 2005: 7). Games can also be powerful learning tools. Several authors (e.g., Gee, 2003; Prensky, 2001) argue that computer games can be more enjoyable, more interesting and thus more effective than traditional learning modes to increase children’s knowledge. Empirical studies that evaluated the impact of the use of games within disciplines such as mathematics, science, language, geography and computer science show positive outcomes in terms of learning effectiveness in relation to curricular objectives (e.g., Papastergiou, 2009; Rosas et al., 2003). However, these authors mainly focus on the learning ability of games rather than their persuasive impact for social marketing purposes. In the area of health education, playing computer games has often been seen with skepticism (e.g., Bale, 1994; Funk and Buchman, 1995)

Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation

Cloud Computing As a Tool for Enhancing Ecological Goals?

Cloud computing has been introduced as a promising information technology (IT) that embodies not only economic advantages in terms of increased efficiency but also ecological gains through saving energy. The latter has become particularly important in view of the rising energy costs of IT. The present study analyzes whether necessary preconditions for accepting cloud computing as a new infrastructure, such as awareness and perceived net value, exist on the part of the users. The analysis is based on a combined research framework of the theory of reasoned action (TRA) and the technology acceptance model (TAM) in a cloud computing setting. Two consumer surveys, the one to elicit beliefs and the second to gain insight into the ranking of the variables, are employed. This study uses structural equation modeling (SEM) to evaluate the hypotheses. The results indicate support for the proposed research framework. Surprisingly however, the ecological factor does not play a role in forming cloud computing intentions, regardless of prior knowledge or experience. Empirical evidence of this study suggests increasing efforts for informing actual and potential users, particularly in respect to possible ecological advantages through applying the new IT infrastructure

Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus

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