Effects of energy dependence in the quasiparticle density of states on far-infrared absorption in the pseudogap state

We derive a relationship between the optical conductivity scattering rate 1/\tau(\omega) and the electron-boson spectral function \alpha^2F(\Omega) valid for the case when the electronic density of states, N(\epsilon), cannot be taken as constant in the vicinity of the Fermi level. This relationship turned out to be useful for analyzing the experimental data in the pseudogap state of cuprate superconductors.Comment: 8 pages, RevTeX4, 1 EPS figure; final version published in PR

Understanding Cheating: From the University Classroom to the Workplace

Cheating is defined as taking information, credit, or reward that one neither deserves nor did the work to achieve. Cheating behavior is often seen as a driver behind many of our current economic problems and the temptation to cheat has been associated with our downward slide in business practice for the past two decades. For example, the current housing crisis has been explained in part as banks cheating in terms of qualifying people for loans. Additionally, current headlines focus on legislators and Wall Street analysts who cheat investors by unfairly taking advantage of inside information not publicly available to others in the market. Cheating defeats fairness of competition and undermines the basis of business integrity. Writers in the business press are expressing concern over the widespread levels of ‘cheating’ among business executives. Enron, HealthSouth, and Tyco, all cheated shareholders in order to pad the pockets of their corporate executives. Some of the smartest and best business minds have fallen subject to the temptation to cheat and the result has been some of the most wideranging financial regulation in our history. The Sarbanes-Oxley and Dodd-Frank Acts were enacted in reaction to the perceived prevalence of cheating by business managers. The controversial new Consumer Financial Protection Bureau is yet another attempt to address this problem. Classroom teachers are also experiencing a growing concern over what seems to be ever increasing levels of cheating among students. Students cheat for a variety of reasons including a felt pressure to maintain good grades and because they perceive many opportunities to cheat but few real penalties for getting caught. Instructor behavior may unwittingly exacerbate the problem by giving unclear or arbitrary assignments that create a climate for cheating when students view the benefits of figuring out and completing the assignment honestly to be minimal at best. The problem of classroom cheating is that students are likely to carry the behaviors they learn in the classroom into the workplace. It is this prospect that leads us to examine the nature of classroom cheating as a precursor to what might happen in actual business settings. It is likely that many of us have cheated at something or in some way, however unimportant, in our lives. We may have taken advantage of unsuspecting others in sports or play and the amount of harm done is probably very little and accepted as part of the interaction. But when the stakes get higher and include academic or business integrity and the validity of a grade or financial statement are at stake, then cheating has significant potential consequences, and needs to be both understood and managed

The possible importance of synchrotron/inverse Compton losses to explain fast mm-wave and hard X-ray emission of a solar event

The solar burst of 21 May 1984, presented a number of unique features. The time profile consisted of seven major structures (seconds), with a turnover frequency of greater than or approximately 90 GHz, well correlated in time to hard X-ray emission. Each structure consisted of multiple fast pulses (0.1 seconds), which were analyzed in detail. A proportionality between the repetition rate of the pulses and the burst fluxes at 90 GHz and greater than or approximately 100 keV hard X-rays, and an inverse proportionality between repetition rates and hard X-ray power law indices were found. A synchrotron/inverse Compton model was applied to explain the emission of the fast burst structures, which appear to be possible for the first three or four structures

Observations of OJ 287 from the Geodetic VLBI Archive of the Washington Correlator

We present 27 geodetic VLBI maps of OJ 287 obtained from the archive of the Washington correlator. The observations presented here were made between 1990 October and 1996 December. During this period a sequence of six superluminal components has been identified. We measured the proper motion of these components to be approximately 0.5 mas/yr, which is about twice as high as that seen in previous VLBI observations. These results imply a higher component ejection rate than previously observed, in good agreement with the observed occurrences of radio outbursts. We have examined a possible connection between VLBI components and optical flares in the framework of a binary black hole system.Comment: 9 pages, 5 included figures, emulateapj.sty, accepted to The Astrophysical Journa

The possible importance of synchrotron/inverse Compton losses to explain fast MM-wave and hard X-ray emission of a solar event

The solar burst of 21 May 1984 presented a number of unique features. The time profile consisted of seven major structures (seconds), with a turnover frequency or approx. 90 GHz, well correlated in time to hard X-ray emission. Each structure consisted of multiple fast pulses (.1 seconds), which were analyzed in detail. A proportionality between the repetition rate of the pulses and the burst fluxes at 90 GHz and or approx. 100 keV hard X-rays, and an inverse proportionality between repetition rates and hard X-rays power law indices have been found. A synchrotron/inverse Compton model has been applied to explain the emission of the fast burst structures, which appear to be possible for the first three or four structures

A new class of solar burst with MM-wave emission but only at the highest frequency (90 GHz)

High sensitivity and high time resolution solar observations at 90 GHz (lambda = 3.3 mm) have identified a unique impulsive burst on May 21, 1984 with emission that was more intense at this frequency than at lower frequencies. The first major time structure of the burst was over 10 times more intense at 90 GHz than at 30 GHz, 7 GHz, or 2.8 GHz.Only 6 seconds later, the 30 GHz impulsive structures started to be observed but still with lower intensity than at 90 GHz. Hard X-ray time structures at energies above 25 keV were almost identical to the 90 GHZ structures (to better than one second). All 90 GHz major time structures consisted of trains of multiple subsecond pulses with rise times as short as 0.03 sec and amplitudes large compared to the mean flux. When detectable, the 30 GHz subsecond pulses had smaller relative amplitude and were in phase with the corresponding 90 GHz pulses

Simulation of a High-Frequency Link of Phase Comparison Protection of Transmission Lines for Optimization its Settings

The objective of this work is to determine the influence of high-frequency link (HFL) on functioning of phase comparison protection (PCP) through the usage of detailed models that take into account specific features of the PCP and processes in HFL. The article describes the case of the most common variant of the high frequency signal transmission by using a scheme 'phase-to-ground'. To verify suggested solution the developed mathematical model of HFL has been studied. Presented simulation results confirm the effectiveness of the proposed approach for solving the problem

Multiple energetic injections in a strong spike-like solar burst

An intense and fast spike-like solar burst was built up of short time scale structures superimposed on an underlying gradual emission, the time evolution of which shows remarkable proportionality between hard X-ray and microwave fluxes. The finer time structure were best defined at mm-microwaves. At the peak of the event, the finer structures repeat every 30x60ms. The more slowly varying component with a time scale of about 1 second was identified in microwave hard X-rays throughout the burst duration. It is suggested that X-ray fluxes might also be proportional to the repetition rate of basic units of energy injection (quasi-quantized). The relevant parameters of one primary energy release site are estimated both in the case where hard X-rays are produced primarily by thick-target bremsstrahlung, and when they are purely thermal. The relation of this figure to global energy considerations is discussed

Optical photometry and spectroscopy of the 1987A-like supernova 2009mw

We present optical photometric and spectroscopic observations of the 1987A-like supernova (SN) 2009mw. Our $BVRI$ and $g'r'i'z'$ photometry covers 167 days of evolution, including the rise to the light curve maximum, and ends just after the beginning of the linear tail phase. We compare the observational properties of SN 2009mw with those of other SNe belonging to the same subgroup, and find that it shows similarities to several objects. The physical parameters of the progenitor and the SN are estimated via hydrodynamical modelling, yielding an explosion energy of $1$ foe, a pre-SN mass of $19\,{\rm M_{\odot}}$, a progenitor radius as $30\,{\rm R_{\odot}}$ and a $^{56}$Ni mass as $0.062\,{\rm M_{\odot}}$. These values indicate that the progenitor of SN 2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We examine the host environment of SN 2009mw and find that it emerged from a population with slightly sub-solar metallicty.Comment: 11 pages, 12 figures, accepted for publication in MNRA