An additional study and implementation of tone calibrated technique of modulation

The Tone Calibrated Technique (TCT) was shown to be theoretically free from an error floor, and is only limited, in practice, by implementation constraints. The concept of the TCT transmission scheme along with a baseband implementation of a suitable demodulator is introduced. Two techniques for the generation of the TCT signal are considered: a Manchester source encoding scheme (MTCT) and a subcarrier based technique (STCT). The results are summarized for the TCT link computer simulation. The hardware implementation of the MTCT system is addressed and the digital signal processing design considerations involved in satisfying the modulator/demodulator requirements are outlined. The program findings are discussed and future direction are suggested based on conclusions made regarding the suitability of the TCT system for the transmission channel presently under consideration

An aeronautical mobile satellite experiment

The various activities and findings of a NASA/FAA/COMSAT/INMARSAT collaborative aeronautical mobile satellite experiment are detailed. The primary objective of the experiment was to demonstrate and evaluate an advanced digital mobile satellite terminal developed at the Jet Propulsion Laboratory under the NASA Mobile Satellite Program. The experiment was a significant milestone for NASA/JPL, since it was the first test of the mobile terminal in a true mobile satellite environment. The results were also of interest to the general mobile satellite community because of the advanced nature of the technologies employed in the terminal

The Impact of Atmospheric Fluctuations on Degree-scale Imaging of the Cosmic Microwave Background

Fluctuations in the brightness of the Earth's atmosphere originating from water vapor are an important source of noise for ground-based instruments attempting to measure anisotropy in the Cosmic Microwave Background. This paper presents a model for the atmospheric fluctuations and derives simple expressions to predict the contribution of the atmosphere to experimental measurements. Data from the South Pole and from the Atacama Desert in Chile, two of the driest places on Earth, are used to assess the level of fluctuations at each site.Comment: 29 pages, 7 figures, 1 table, appears in The Astrophysical Journa

Detection of livestock-associated meticillin-resistant Staphylococcus aureus CC398 in retail pork, United Kingdom, February 2015

No abstract available

Caveolin-1 expression and cavin stability regulate caveolae dynamics in adipocyte lipid store fluctuation

Adipocytes specialized in the storage of energy as fat are among the most caveolae-enriched cell types. Loss of caveolae produces lipodystrophic diabetes in humans, which cannot be reversed by endothelial rescue of caveolin expression in mice, indicating major importance of adipocyte caveolae. However, how caveolae participate in fat cell functions is poorly understood. We investigated dynamic conditions of lipid store fluctuations and demonstrate reciprocal regulation of caveolae density and fat cell lipid droplet storage. We identified caveolin-1 expression as a crucial step in adipose cell lines and in mice to raise the density of caveolae, to increase adipocyte ability to accommodate larger lipid droplets, and to promote cell expansion by increased glucose utilization. In human subjects enrolled in a trial of 8 weeks of overfeeding to promote fattening, adipocyte expansion response correlated with initial caveolin-1 expression. Conversely, lipid mobilization in cultured adipocytes to induce lipid droplet shrinkage led to biphasic response of cavin-1 with ultimate loss of expression of cavin-1 and -3 and EHD2 by protein degradation, coincident with caveolae disassembly. We have identified the key steps in cavin/caveolin interplay regulating adipocyte caveolae dynamics. Our data establish that caveolae participate in a unique cell response connected to lipid store fluctuation, suggesting lipid-induced mechanotension in adipocytes

The lipoatrophic caveolin-1 deficient mouse model reveals autophagy in mature adipocytes

Adipose tissue lipoatrophy caused by caveolin gene deletion in mice is not linked to defective adipocyte differentiation. We show that adipose tissue development cannot be rescued by endothelial specific caveolin-1 re-expression, indicating primordial role of caveolin in mature adipocytes. Partial or total caveolin deficiency in adipocytes induced broad protein expression defects, including but not limited to previously described downregulation of insulin receptor. Global alterations in protein turnover, and accelerated degradation of long-lived proteins were found in caveolin-deficient adipocytes. Lipidation of endogenous LC3 autophagy marker and distribution of GFP-LC3 into aggregates demonstrated activated autophagy in the absence of caveolin-1 in adipocytes. Furthermore, electron microscopy revealed autophagic vacuoles in caveolin-1 deficient but not control adipocytes. Surprisingly, significant levels of lipidated LC3-II were found around lipid droplets of normal adipocytes, maintained in nutrient-rich conditions or isolated from fed mice, which do not display autophagy. Altogether, these data indicate that caveolin deficiency induce autophagy in adipocytes, a feature that is not a physiological response to fasting in normal fat cells. This likely resulted from defective insulin and lipolytic responses that converge in chronic nutrient shortage in adipocytes lacking caveolin-1. This is the first report of a pathological situation with autophagy as an adaptative response to adipocyte failure

Sum rules and electrodynamics of high-Tc cuprates in the pseudogap state

We explore connections between the electronic density of states (DOS) in a conducting system and the frequency dependence of the scattering rate $1/\tau(\omega)$ inferred from infrared spectroscopy. We show that changes in the DOS upon the development of energy gaps can be reliably tracked through the examination of the $1/\tau(\omega)$ spectra using the sum rules discussed in the text. Applying this analysis to the charge dynamics in high-$T_c$ cuprates we found radically different trends in the evolution of the DOS in the pseudogap state and in the superconducting state.Comment: 4 pages, 3 figure

Invariant Regularization of Anomaly-Free Chiral Theories

We present a generalization of the Frolov-Slavnov invariant regularization scheme for chiral fermion theories in curved spacetimes. local gauge symmetries of the theory, including local Lorentz invariance. The perturbative scheme works for arbitrary representations which satisfy the chiral gauge anomaly and the mixed Lorentz-gauge anomaly cancellation conditions. Anomalous theories on the other hand manifest themselves by having divergent fermion loops which remain unregularized by the scheme. Since the invariant scheme is promoted to also include local Lorentz invariance, spectator fields which do not couple to gravity cannot be, and are not, introduced. Furthermore, the scheme is truly chiral (Weyl) in that all fields, including the regulators, are left-handed; and only the left-handed spin connection is needed. The scheme is, therefore, well suited for the study of the interaction of matter with all four known forces in a completely chiral fashion. In contrast with the vectorlike formulation, the degeneracy between the Adler-Bell-Jackiw current and the fermion number current in the bare action is preserved by the chiral regularization scheme.Comment: 28pgs, LaTeX. Typos corrected. Further remarks on singlet current

Universal Torsion-Induced Interaction from Large Extra Dimensions

We consider the Kaluza-Klein (KK) scenario in which only gravity exists in the bulk. Without the assumption of symmetric connection, the presence of brane fermions induces torsion. The result is a universal axial contact interaction that dominates those induced by KK gravitons. This enhancement arises from a large spin density on the brane. Using a global fit to Z-pole observables, we find the 3 sigma bound on the scale of quantum gravity to be 28 TeV for n=2. If Dirac or light sterile neutrinos are present, the data from SN1987A increase the bound to \sqrt{n}M_S >= 210 TeV.Comment: 9 pages REVTeX, 1 postscript figure, uses axodraw.st

Three-body structure of low-lying 18Ne states

We investigate to what extent 18Ne can be descibed as a three-body system made of an inert 16O-core and two protons. We compare to experimental data and occasionally to shell model results. We obtain three-body wave functions with the hyperspherical adiabatic expansion method. We study the spectrum of 18Ne, the structure of the different states and the predominant transition strengths. Two 0+, two 2+, and one 4+ bound states are found where they are all known experimentally. Also one 3+ close to threshold is found and several negative parity states, 1-, 3-, 0-, 2-, most of them bound with respect to the 16O excited 3- state. The structures are extracted as partial wave components, as spatial sizes of matter and charge, and as probability distributions. Electromagnetic decay rates are calculated for these states. The dominating decay mode for the bound states is E2 and occasionally also M1.Comment: 17 pages, 5 figures (version to appear in EPJA