A Survey of Best Monotone Degree Conditions for Graph Properties

We survey sufficient degree conditions, for a variety of graph properties, that are best possible in the same sense that Chvatal's well-known degree condition for hamiltonicity is best possible.Comment: 25 page

The Discovery of Cherenkov Radiation and its use in the detection of extensive air showers

Cascades of charged particles are created when high-energy cosmic rays enter the earth's atmosphere: these 'extensive air-showers' are studied to gain information on the energy spectrum, arrival direction distribution and mass composition of the particles above 1014 eV where direct observations using instruments carried by balloons or satellites become impractical. Detection of light in the visible and ultra-violet ranges of the electromagnetic spectrum plays a key role in this work, the two processes involved being the emission of Cherenkov light and the production of fluorescence radiation. In this paper I will outline some of the history of the discovery of the Cherenkov process and describe the use to which it has been put in the study of extensive air-showers at ground level.Comment: To appear in Proceedings of CRIS2010: Cosmic Ray International Seminar on '100 years of Cosmic Rays: from Pioneering Experiments to Physics in Space

Fusion cuisine:A functional approach to interdisciplinary cooking in journalism studies

Journalism studies as an academic field is characterized by multidisciplinarity. Focusing on one object of study, journalism and the news, it established itself by integrating and synthesizing approaches from established disciplines – a tendency that lives on today. This constant gaze to the outside for conceptual inspiration and methodological tools lends itself to a journalism studies that is a fusion cuisine of media, communication, and related scholarship. However, what happens when this object becomes as fragmented and multifaceted as the ways we study it? This essay addresses the challenge of multiplicity in journalism studies by introducing an audience-centred, functional approach to scholarship. We argue this approach encourages the creative intellectual advancements afforded by interdisciplinary experimental cooking while respecting the classical intellectual questions that helped define the culinary tradition of journalism studies in the first place. In so doing, we offer a recipe for journalism studies fusion cooking that: (1) considers technological change (audiences’ diets), (2) analyses institutional change (audiences’ supermarket of information), and (3) evaluates journalism’s societal and democratic impact (audiences’ cuisines and health)

Accelerated and Scalable C(sp³)-H Amination via Decatungstate Photocatalysis Using a Flow Photoreactor Equipped with High-Intensity LEDs

[Image: see text] Carbon–nitrogen bonds are ubiquitous in biologically active compounds, prompting synthetic chemists to design various methodologies for their preparation. Arguably, the ideal synthetic approach is to be able to directly convert omnipresent C–H bonds in organic molecules, enabling even late-stage functionalization of complex organic scaffolds. While this approach has been thoroughly investigated for C(sp(2))–H bonds, only few examples have been reported for the direct amination of aliphatic C(sp(3))–H bonds. Herein, we report the use of a newly developed flow photoreactor equipped with high intensity chip-on-board LED technology (144 W optical power) to trigger the regioselective and scalable C(sp(3))–H amination via decatungstate photocatalysis. This high-intensity reactor platform enables simultaneously fast results gathering and scalability in a single device, thus bridging the gap between academic discovery (mmol scale) and industrial production (>2 kg/day productivity). The photocatalytic transformation is amenable to the conversion of both activated and nonactivated hydrocarbons, leading to protected hydrazine products by reaction with azodicarboxylates. We further validated the robustness of our manifold by designing telescoped flow approaches for the synthesis of pyrazoles, phthalazinones and free amines

Can biological quantum networks solve NP-hard problems?

There is a widespread view that the human brain is so complex that it cannot be efficiently simulated by universal Turing machines. During the last decades the question has therefore been raised whether we need to consider quantum effects to explain the imagined cognitive power of a conscious mind. This paper presents a personal view of several fields of philosophy and computational neurobiology in an attempt to suggest a realistic picture of how the brain might work as a basis for perception, consciousness and cognition. The purpose is to be able to identify and evaluate instances where quantum effects might play a significant role in cognitive processes. Not surprisingly, the conclusion is that quantum-enhanced cognition and intelligence are very unlikely to be found in biological brains. Quantum effects may certainly influence the functionality of various components and signalling pathways at the molecular level in the brain network, like ion ports, synapses, sensors, and enzymes. This might evidently influence the functionality of some nodes and perhaps even the overall intelligence of the brain network, but hardly give it any dramatically enhanced functionality. So, the conclusion is that biological quantum networks can only approximately solve small instances of NP-hard problems. On the other hand, artificial intelligence and machine learning implemented in complex dynamical systems based on genuine quantum networks can certainly be expected to show enhanced performance and quantum advantage compared with classical networks. Nevertheless, even quantum networks can only be expected to efficiently solve NP-hard problems approximately. In the end it is a question of precision - Nature is approximate.Comment: 38 page