Littoral sea clutter returns at 94GHz

This paper reports and discusses measurements made of the returns from sea clutter in the littoral at 94GHz using the SAFIRE demonstration radar. These measurements add significantly to the limited data which is available on sea clutter at 94GHz as well as showing how a radar developed to assist the public understanding of technology can also be used for research purposes. Littoral clutter measurements are proportionately more important at 94GHz than at lower frequencies because the short range of radars at these frequencies means that they are much more likely to be operating in this environment than in the open sea. The measurements show peak backscatter levels of about -22dB (sea state 3, 2° grazing angle), but this is concentrated around the breaking wave crests, and the mean value is close to the -30dB reported by other workers. At the high range resolutions used, the resultant distributions appear very longtailed. The data also shows a useful insight into the behaviour of sea clutter when viewed with circular polarisation, for which the peak values are similar to those observed with linear polarisations, but the mean values are much lower.Postprin

Seeking Evolution of Dark Energy

We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state $\omega(Z)$. We focus on the value of redshift Z* at which the cosmic late time acceleration begins and $\ddot{a}(Z^{*}) = 0$. Four $\omega(Z)$ are studied, including the well-known CPL model and a new model that has advantages when describing the entire expansion era. If dark energy is represented by a CC model with $\omega \equiv -1$, the present ranges for $\Omega_{\Lambda}(t_0)$ and $\Omega_m(t_0)$ imply that Z* = 0.743 with 4% error. We discuss the possible implications of a model independent measurement of Z* with better accuracy.Comment: 9 pages, LaTeX, 5 figure

Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA

We report results of air monitoring started due to the recent natural catastrophe on 11 March 2011 in Japan and the severe ensuing damage to the Fukushima Dai-ichi nuclear reactor complex. On 17-18 March 2011, we registered the first arrival of the airborne fission products 131-I, 132-I, 132-Te, 134-Cs, and 137-Cs in Seattle, WA, USA, by identifying their characteristic gamma rays using a germanium detector. We measured the evolution of the activities over a period of 23 days at the end of which the activities had mostly fallen below our detection limit. The highest detected activity amounted to 4.4 +/- 1.3 mBq/m^3 of 131-I on 19-20 March.Comment: 7 pages, 5 figures, published in Journal of Environmental Radioactivit

Friedmann-like equations for High Energy Area of Universe

In this paper, evolution of the high energy area of universe, through the scenario of 5 dimensional (5D) universe, has been studied. For this purpose, we solve Einstein equations for 5D metric and 5D perfect fuid to derive Friedmann-like equations. Then we obtain the evolution of scale factor and energy density with respect to both space-like and time-like extra dimensions. We obtain the novel equations for the space-like extra dimension and show that the matter with zero pressure cannot exist in the bulk. Also, for dark energy fuid and vacuum fluid, we have both accelerated expansion and contraction in the bulk.Comment: 9 pages, Accepted to publication in IJTP 26 June 2012. arXiv admin note: substantial text overlap with arXiv:1202.497

Bulk Scale Factor at Very Early Universe

In this paper we propose a higher dimensional Cosmology based on FRW model and brane-world scenario. We consider the warp factor in the brane-world scenario as a scale factor in 5-dimensional generalized FRW metric, which is called as bulk scale factor, and obtain the evolution of it with space-like and time-like extra dimensions. It is then showed that, additional space-like dimensions can produce exponentially bulk scale factor under repulsive strong gravitational force in the empty universe at a very early stage.Comment: 7 pages, October 201

Particle-Like Description in Quintessential Cosmology

Assuming equation of state for quintessential matter: $p=w(z)\rho$, we analyse dynamical behaviour of the scale factor in FRW cosmologies. It is shown that its dynamics is formally equivalent to that of a classical particle under the action of 1D potential $V(a)$. It is shown that Hamiltonian method can be easily implemented to obtain a classification of all cosmological solutions in the phase space as well as in the configurational space. Examples taken from modern cosmology illustrate the effectiveness of the presented approach. Advantages of representing dynamics as a 1D Hamiltonian flow, in the analysis of acceleration and horizon problems, are presented. The inverse problem of reconstructing the Hamiltonian dynamics (i.e. potential function) from the luminosity distance function $d_{L}(z)$ for supernovae is also considered.Comment: 35 pages, 26 figures, RevTeX4, some applications of our treatment to investigation of quintessence models were adde

Energetics and stability of nanostructured amorphous carbon

Monte Carlo simulations, supplemented by ab initio calculations, shed light into the energetics and thermodynamic stability of nanostructured amorphous carbon. The interaction of the embedded nanocrystals with the host amorphous matrix is shown to determine in a large degree the stability and the relative energy differences among carbon phases. Diamonds are stable structures in matrices with sp^3 fraction over 60%. Schwarzites are stable in low-coordinated networks. Other sp^2-bonded structures are metastable.Comment: 11 pages, 7 figure

When Time Is Critical, Is Informed Consent Less So? A Discussion of Patient Autonomy in Emergency Neurosurgery

Neurosurgical interventions frequently occur in an emergency setting. In this setting, patients often have impaired consciousness and are unable to directly express their values and wishes regarding their treatment. The limited time available for clinical decision making has great ethical implications, as the informed consent procedure may become compromised. The ethical situation may be further challenged by different views between the patient, family members, and the neurosurgeon; the presence of advance directives; the use of an innovative procedure; or if the procedure is part of a research project. This moral opinion piece presents the implications of time constraints and a lack of patient capacity for autonomous decision making in emergency neurosurgical situations. Potential solutions to these challenges are presented that may help to improve ethical patient management in emergency settings. Emergency neurosurgery challenges the respect of autonomy of the patient. The outcome in most scenarios will rely on the neurosurgeon acting in a professional way to manage each unique situation in an ethically sound manner.Scientific Assessment and Innovation in Neurosurgical Treatment Strategie

Rotating Resonator-Oscillator Experiments to Test Lorentz Invariance in Electrodynamics

In this work we outline the two most commonly used test theories (RMS and SME) for testing Local Lorentz Invariance (LLI) of the photon. Then we develop the general framework of applying these test theories to resonator experiments with an emphasis on rotating experiments in the laboratory. We compare the inherent sensitivity factors of common experiments and propose some new configurations. Finally we apply the test theories to the rotating cryogenic experiment at the University of Western Australia, which recently set new limits in both the RMS and SME frameworks [hep-ph/0506074].Comment: Submitted to Lecture Notes in Physics, 36 pages, minor modifications, updated list of reference