University of Bremen

About: University of Bremen is a education organization based out in Bremen, Germany. It is known for research contribution in the topics: Population & Context (language use). The organization has 14563 authors who have published 37279 publications receiving 970381 citations. The organization is also known as: Universität Bremen.

Societal issues and their importance for contemporary science education—a pedagogical justification and the state-of-the-art in israel, germany, and the usa

Abstract: One common theme underlying recent reports on science education is that the content of school science and its related pedagogical approaches are not aligned with the interests and needs of both society and the majority of the students. Most students do not find their science classes interesting and motivating. These claims are especially valid regarding those students who, in the future, will probably not embark on a career in science or engineering but will need science and technology personally and functionally as literate citizens. One key problem seems to be that few science programs around the world teach how science is linked to those issues that are relevant to students’ life, environment, and role as a citizen. As a result, many students are unable to participate in societal discussions about science and its related technological applications. This paper discusses the need to incorporate socioscientific ideas into the science curricula more thoroughly. This recommendation is supported by a theoretical rationale from various sources leading to a reflection about common practices in science education in three countries: Israel, Germany, and the USA. The state-of-the-art, potentials, and barriers of effective implementation are discussed.

Antibacterial Properties of Silver‐Doped Titania

Abstract: Silver has been known to exhibit strong cytotoxicity towards a broad range of micro-organisms. Silver composites with a tailored slow silver-release rate are currently being investigated for various applications. Silver has an oligodynamic effect, that is, silver ions are capable of causing a bacteriostatic (growth inhibition) or even a bactericidal (antibacterial) impact. Nanometer-sized inorganic particles and composites display unique physical and chemical properties and represent a unique class of materials in the development of novel devices, which can be used in numerous physical, biological, biomedical, and pharmaceutical applications. Silver composites have applications in many industries, such as aerospace, surface coatings (e.g., in refrigerators, food processing, kitchen furniture), and for use in hospitals. Research indicates that silver is also effective in purification systems for disinfecting water or air. However, in order to make the use of silver economical, there is a need to find cheaper ways of using silver in potential applications without jeopardizing its functionalities. The bactericidal behavior of silver nanoparticles is attributed to the presence of electronic effects, which are a result of the changes in the local electronic structure of the surfaces of the smaller-sized particles. These effects are considered to be contributing towards an enhancement of the reactivity of silver-nanoparticle surfaces. It has been reported that ionic silver strongly interacts with thiol groups of vital enzymes and inactivates them. It has been suggested that DNA loses its replication ability once the bacteria have been treated with silver ions. Two-dimensional (2D) electrophoresis and protein-identification analyses of the antibacterial action of silver nanoparticles have revealed an accumulation of envelope-protein precursors. Silver nanoparticles target the bacterial membrane, which leads to the deACHTUNGTRENNUNGstabilization of the plasma-membrane potential and the depletion of the levels of intracellular adenosine triphosphate (ATP), resulting in bacterial cell death. Bacteria cells grow by a process called binary fission in which one cell doubles in size then splits in half to produce two identical daughter cells. If a bacterial population in an environment is without any growth restrictions by nutrient or metabolic products, the number of bacteria increases as an exponential function of time. Bacterial growth can be depicted generally by the growth curve shown in Figure 1.

Global environmental consequences of twenty-first-century ice-sheet melt

Abstract: Government policies currently commit us to surface warming of three to four degrees Celsius above pre-industrial levels by 2100, which will lead to enhanced ice-sheet melt. Ice-sheet discharge was not explicitly included in Coupled Model Intercomparison Project phase 5, so effects on climate from this melt are not currently captured in the simulations most commonly used to inform governmental policy. Here we show, using simulations of the Greenland and Antarctic ice sheets constrained by satellite-based measurements of recent changes in ice mass, that increasing meltwater from Greenland will lead to substantial slowing of the Atlantic overturning circulation, and that meltwater from Antarctica will trap warm water below the sea surface, creating a positive feedback that increases Antarctic ice loss. In our simulations, future ice-sheet melt enhances global temperature variability and contributes up to 25 centimetres to sea level by 2100. However, uncertainties in the way in which future changes in ice dynamics are modelled remain, underlining the need for continued observations and comprehensive multi-model assessments.

A disconnection-tolerant transport for drive-thru Internet environments

Abstract: Today's mobile, wireless, and ad-hoc communications often exhibit extreme characteristics challenging assumptions underlying the traditional way of end-to-end communication protocol design in the Internet. One specific scenario is Internet access from moving vehicles on the road as we are researching in the drive-thru Internet project. Using wireless LAN as a broadly available access technology leads to intermittent - largely unpredictable and usually short-lived - connectivity, yet providing high performance while available. To allow Internet applications to deal reasonably well with such intermittent connectivity patterns, we have introduced a supportive drive-thru architecture. A key component is a "session" protocol offering persistent end-to-end communications even in the presence of interruptions. In this paper, we present the design of the persistent connectivity management protocol (PCMP) and report on findings from our implementation.