A fairytale creation or the beginning of everything: Students ’ pre-instructional conceptions about the Big Bang theory
Publication date: Available online 14 October 2016 Source:Perspectives in Science Author(s): Sarah Aretz, Andreas Borowski, Sascha Schmeling The beginning of the universe, the Big Bang, being an important subdomain in cosmology, marks the very beginning of space and time. Therefore, it has formed the modern scientific worldview. Transferring this to students through science teaching is a frequent request in science literacy discussion (e.g., American Association for the Advancement of Science, 1993; Schecker et al., 2004). However, it is not yet clear in science education if students’ conceptions about the Big Bang ...
Source: Perspectives in Science - October 15, 2016 Category: Science Source Type: research
Science Standards: The foundation of evolution education in the United States
Publication date: Available online 15 October 2016 Source:Perspectives in Science Author(s): Elizabeth Watts, Georgy S. Levit, Uwe Hoßfeld Science standards and textbooks have a huge impact on the manner in which evolution is taught in American classrooms. Standards dictate how much time and what points have to be dedicated to the subject in order to prepare students for state-wide assessments, while the textbooks will largely determine how the subject is presented in the classroom. In the United States both standards and textbooks are determined at the state-level through a political process. Currently there is a tr...
Source: Perspectives in Science - October 15, 2016 Category: Science Source Type: research
Energy consumption in Hodgkin –Huxley type fast spiking neuron model exposed to an external electric field
Publication date: September 2016 Source:Perspectives in Science, Volume 8 Author(s): K. Usha, M.K. Sreepriya, P.A. Subha This paper evaluates the change in metabolic energy required to maintain the signalling activity of neurons in the presence of an external electric field. We have analysed the Hodgkin–Huxley type conductance based fast spiking neuron model as electrical circuit by changing the frequency and amplitude of the applied electric field. The study has shown that, the presence of electric field increases the membrane potential, electrical energy supply and metabolic energy consumption. As the amplitude of...
Source: Perspectives in Science - September 20, 2016 Category: Science Source Type: research
Outage probability analysis of a secondary user in an underlay dual hop cognitive amplify and forward relay network
Publication date: September 2016 Source:Perspectives in Science, Volume 8 Author(s): Kiran Chandra, Soumen Mondal, Sanjay Dhar Roy, Sumit Kundu This paper presents the performance evaluation of a secondary user (SU) in an underlay cognitive dual-hop relaying system considering instantaneous as well as average channel information of the interfering links (from the secondary source and relay to the primary receiver) and the data link from the secondary source to relay, to calculate transmit power and amplifying gain of secondary system. Comparison of above mentioned cases is done for two different scenarios – with di...
Source: Perspectives in Science - September 20, 2016 Category: Science Source Type: research
Synthesis and evaluation of ageing effect on Cu –Al–Be–Mn quaternary Shape Memory Alloys
The objective is to study the effect of thermal ageing at different temperatures A f (above austenitic phase finish temperature) and at different time on shape memory effect and transformation temperatures. The aged specimens or SMA's were studied by DSC, OM and hardness measurements. The results from this study help to find the applications in different thermal conditions. (Source: Perspectives in Science)
Source: Perspectives in Science - September 20, 2016 Category: Science Source Type: research
Investigation of microstructure and mechanical properties of Mg –Zn/Al multilayered composite developed by accumulative roll bonding
Publication date: September 2016 Source:Perspectives in Science, Volume 8 Author(s): Gajanan Anne, M.R. Ramesh, H. Shivananda Nayaka, Shashi Bhushan Arya The present study aims at development of light weight, high strength Mg–2%Zn/Al and Mg–2%Zn/anodized Al based multilayered composite by the accumulative roll bonding (ARB) process. The ultrafine grained multilayer composite was successfully roll bonded by using binary Mg–2%Zn alloy, pure aluminium and anodized aluminium at 300°C with 50% reduction up to 5 passes. Multilayered composites are characterized with respect to microstructure, mechanical properties. ...
Source: Perspectives in Science - September 20, 2016 Category: Science Source Type: research
Magnetic and electrical studies of Ho0.9RE0.1CrO3 (RE=Gd and Yb) multiferroics
We report magnetic and electrical studies on multiferroic systems Ho0.9(RE)0.1CrO3 where RE symbolizes rare earths like Gd and Yb. Solid state diffusion method has been used to synthesize the samples. Structural phase formation has been confirmed with the help of powder X-ray diffraction. Magnetization measurements show canted antiferromagnetic nature with a weak ferromagnetic phase. Néel temperature for Cr3+–Cr3+ ordering shifts to higher side with increasing radii of rare earth cations. Frequency (100Hz to 1MHz) and temperature (300–650K) dependent resistivity measurements are suggestive of semiconducting nature of ...
Source: Perspectives in Science - September 20, 2016 Category: Science Source Type: research
Hybrid AgNP –TiO2 thin film based photoanode for dye sensitized solar cell
This article addresses two major issues in the plasmonic dye solar cell; (i) protection of plasmonic nanoparticles from electrolyte attack and (ii) design of appropriate molecular dye to harvest photon near the plasmonic resonance. This report reveals the synthesis of D-π-A carbazole dye and incorporation of plasmonic Ag nanoparticles (AgNPs) into TiO2 film using Ag–TiO2 gel. We have designed and synthesized an efficient D-π-A carbazole dye molecule whose absorption maxima matches the plasmonic resonance of AgNPs leading to augmented near field effect, enhancing photon harvesting property of dye molecule. This article ...
Source: Perspectives in Science - September 20, 2016 Category: Science Source Type: research
Numerical simulation of spark ignition engine using OpenFOAM ®
Publication date: September 2016 Source:Perspectives in Science, Volume 8 Author(s): B.T. Kannan, P.S. Srivathsan The present work is the numerical investigation of Spark Ignition (SI) engines using an open source Computational Fluid Dynamics (CFD) tool. Investigations on the usage of OpenFOAM® CFD tool has been carried out for the simulation of SI engines using engineFoam solver. Four-valve pent roof type engine is chosen for the present simulations. The standard k–ɛ turbulence model is used along with the Reynolds Averaged Navier Stokes (RANS) equations for simulating the flow field. Energy equation and transport...
Source: Perspectives in Science - September 20, 2016 Category: Science Source Type: research
Biocatalytic retrosynthesis: Redesigning synthetic routes to high-value chemicals
Publication date: Available online 14 September 2016 Source:Perspectives in Science Author(s): Anthony P. Green, Nicholas J. Turner Modern tools for enzyme discovery combined with the development of increasingly reliable strategies for protein engineering have greatly expanded the range of enzymes with suitable properties for practical applications. This situation presents enormous opportunities for the design of sustainable biocatalytic strategies for the production of high-value chemicals. Here, we highlight recent contributions from our laboratory concerning ω-transaminases and monoamine oxidases, two enzyme classe...
Source: Perspectives in Science - September 14, 2016 Category: Science Source Type: research
The enigmatic conservation of enzyme dynamics in evolution
Publication date: Available online 14 September 2016 Source:Perspectives in Science Author(s): Amnon Kohen Examination of the chemical step catalyzed by dihydrofolate reductase (DHFR) suggested preservation of an “ideal” transition state as the enzyme evolves from bacteria to human. This observation is enigmatic: since evolutionary pressure is most effective on enzymes’ second order rate constant (k cat/K M) and since the chemistry is not rate limiting on that kinetic parameter, why is the nature of the chemical step preserved? Studies addressing this question were presented in the 2015 Beilstein ESCEC Symposium a...
Source: Perspectives in Science - September 14, 2016 Category: Science Source Type: research
Identifying the conditions necessary for the thioredoxin ultrasensitive response
Publication date: Available online 14 September 2016 Source:Perspectives in Science Author(s): Johann M. Rohwer, Charl Viljoen, Carl D. Christensen, Lefentse N. Mashamaite, Ché S. Pillay Thioredoxin, glutaredoxin, and peroxiredoxin systems (collectively called redoxins) play critical roles in a large number of redox-sensitive cellular processes. These systems are linked to each other by coupled redox cycles and by common reaction intermediates into a larger network. Previous results from a realistic computational model of the Escherichia coli thioredoxin system developed in our group have revealed several modes of ...
Source: Perspectives in Science - September 14, 2016 Category: Science Source Type: research
The bacterial catabolism of polycyclic aromatic hydrocarbons: Characterization of three hydratase-aldolase-catalyzed reactions
Publication date: Available online 14 September 2016 Source:Perspectives in Science Author(s): Jake A. LeVieux, William H. Johnson, Kaci Erwin, Wenzong Li, Yan Zhang, Christian P. Whitman Polycyclic aromatic hydrocarbons (PAHs) are highly toxic, pervasive environmental pollutants with mutagenic, teratogenic, and carcinogenic properties. There is interest in exploiting the nutritional capabilities of microbes to remove PAHs from various environments including those impacted by improper disposal or spills. Although there is a considerable body of literature on PAH degradation, the substrates and products for many of ...
Source: Perspectives in Science - September 14, 2016 Category: Science Source Type: research
Tools and strategies for discovering novel enzymes and metabolic pathways
Publication date: Available online 13 September 2016 Source:Perspectives in Science Author(s): John A. Gerlt The number of entries in the sequence databases continues to increase exponentially – the UniProt database is increasing with a doubling time of ∼4 years (2% increase/month). Approximately 50% of the entries have uncertain, unknown, or incorrect function annotations because these are made by automated methods based on sequence homology. If the potential in complete genome sequences is to be realized, strategies and tools must be developed to facilitate experimental assignment of functions to uncharacterized p...
Source: Perspectives in Science - September 13, 2016 Category: Science Source Type: research
From enzymology to systems biology and back - Epilogue
Publication date: Available online 1 September 2016 Source:Perspectives in Science Author(s): Peter Halling (Source: Perspectives in Science)
Source: Perspectives in Science - September 1, 2016 Category: Science Source Type: research
