Cryptography: Mathematical Advancements on Cyber Security

The origin of cryptography, the study of encoding and decoding messages, dates back to ancient times around 1900 BC. The ancient Egyptians enlisted the use of basic encryption techniques to conceal personal information. Eventually, the realm of cryptography grew to include the concealment of more important information, and cryptography quickly became the backbone of cyber security. Many companies today use encryption to protect online data, and the government even uses encryption to conceal confidential information. Mathematics played a huge role in advancing the methods of cryptography. By looking at the math behind the most basic methods to the newest methods of cryptography, one can learn how cryptography has advanced and will continue to advance

Life as an early career researcher: Ruth Bower

Ruth Bower talks to Francesca Lake, Managing Editor: Ruth is currently researching head and neck cancer chemoradiotherapy regimens utilizing microfluidic technology to maintain and interrogate biopsies. Tissue response is investigated using a variety of whole tissue and cellular analytical techniques with a view toward personalized medicine. She is currently pursuing her PhD within the head and neck cancer research group at Hull University (UK). Ruth obtained a first class (Hons) degree in Biological Sciences from Lancaster University (UK) during which time she spent a year at the University of Wollongong (Australia)

Constraining the Rate of Relativistic Jets from Tidal Disruptions Using Radio Surveys

Tidal disruption of stars by massive black holes produce transient accretion flows that flare at optical, UV, and X-ray wavelengths. At late times, these accretion flows may launch relativistic jets that can be detected through the interaction of the jet with the dense interstellar medium of the galaxy. We present an upper limit for the flux density of a radio counterpart to a tidal disruption event detected by GALEX that is a factor of 6 below theoretical predictions. We also examine existing radio surveys for transients with a time scale of 1 year and use these to set a $2 \sigma$ upper limit on the rate of tidal disruption events producing relativistic jets of ~14 x 10^-7 Mpc^-3 y^-1. This rate is an order of magnitude lower than the highest values from theoretical models and is consistent with detection rates from optical and X-ray surveys.Comment: Accepted for publication in ApJ

Husserl on Hallucination: A Conjunctive Reading

Several commentators have recently attributed conflicting accounts of the relation between veridical perceptual experience and hallucination to Husserl. Some say he is a proponent of the conjunctive view that the two kinds of experience are fundamentally the same. Others deny this and purport to find in Husserl distinct and non-overlapping accounts of their fundamental natures, thus committing him to a disjunctive view. My goal is to set the record straight. Having briefly laid out the problem under discussion and the terms of the debate, I then review the proposals that have been advanced, disposing of some and marking others for further consideration. A.D. Smith’s disjunctive reading is among the latter. I discuss it at length, arguing that Smith fails to show that Husserl’s views on perceptual experience entail a form of disjunctivism. Following that critical discussion, I present a case for a conjunctive reading of Husserl’s account of perceptual experience

System aspects of spacecraft charging

Satellites come in a variety of sizes and configurations including spinning satellites and three-axis stabilized satellites. All of these characteristics have a significant effect on spacecraft charging considerations. There are, however, certain fundamentals which can be considered which indicate the nature and extent of the problem. The global positioning system satellite serves to illustrate certain characteristics

The Entropy-Driven X-ray Evolution of Galaxy Clusters

Observations of the evolution of the galaxy cluster X-ray luminosity function suggest that the entropy of the intra-cluster medium plays a significant role in determining the development of cluster X-ray properties. I present a theoretical framework in which the evolution of the entropy of the central intra-cluster gas is explicitly taken into account. The aim of this work is to develop a theoretical context within which steadily improving measurements of the X-ray luminosities and temperatures of distant galaxy clusters can be interpreted. I discuss the possible range of entropy evolution parameters and relate these to the physical processes heating and cooling the intra-cluster medium. The practical application of this work is demonstrated by combining currently available evolutionary constraints on the X-ray luminosity function and the luminosity--temperature correlation to determine the best-fitting model parameters.Comment: 9 pages Tex including 4 postscript figures. To be appear in MNRAS. minor miss-quote correcte

Digital input is buffered to real-time analog display

Buffering technique utilizes nine-bit binary counter and holding register of eight flip-flops. These flip-flops form the memory device that allows precise asynchronous conversion of the digital source data. Counter generates a waveform which is passed through a low pass filter to recover data in analog form