Neutrinos in a left-right model with a horizontal symmetry

We analyze the lepton sector of a Left-Right Model based on the gauge group SU(2)_L x SU(2)_R x U(1), concentrating mainly on neutrino properties. Using the seesaw mechanism and a horizontal symmetry, we keep the right-handed symmetry breaking scale relatively low, while simultaneously satisfying phenomenological constraints on the light neutrino masses. We take the right-handed scale to be of order 10's of TeV and perform a full numerical analysis of the model's parameter space, subject to experimental constraints on neutrino masses and mixings. The numerical procedure yields results for the right-handed neutrino masses and mixings and the various CP-violating phases. We also discuss phenomenological applications of the model to neutrinoless double beta decay, lepton-flavor-violating decays (including decays such as \tau \to 3\mu) and leptogenesis.Comment: 26 pages, 4 figure

The metabolic syndrome adds utility to the prediction of mortality over its components: The Vietnam Experience Study

Background\ud The metabolic syndrome increases mortality risk. However, as “non-affected” individuals may still have up to two risk factors, the utility of using three or more components to identify the syndrome, and its predictive advantage over individual components have yet to be determined.\ud \ud Methods\ud Participants, male Vietnam-era veterans (n = 4265) from the USA, were followed-up from 1985/1986 for 14.7 years (61,498 person-years), and all-cause and cardiovascular disease deaths collated. Cox's proportional-hazards regression was used to assess the effect of the metabolic syndrome and its components on mortality adjusting for a wide range of potential confounders.\ud \ud Results\ud At baseline, 752 participants (17.9%) were identified as having metabolic syndrome. There were 231 (5.5%) deaths from all-causes, with 60 from cardiovascular disease. After adjustment for a range of covariates, the metabolic syndrome increased the risk of all-cause, HR 2.03, 95%CI 1.52, 2.71, and cardiovascular disease mortality, HR 1.92, 95%CI 1.10, 3.36. Risk increased dose-dependently with increasing numbers of components. The increased risk from possessing only one or two components was not statistically significant. The adjusted risk for four or more components was greater than for only three components for both all-cause, HR 2.30, 95%CI 1.45, 3.66 vs. HR 1.70, 95%CI 1.11, 2.61, and cardiovascular disease mortality, HR 3.34, 95%CI 1.19, 9.37 vs. HR 2.81, 95%CI 1.07, 7.35. The syndrome was more informative than the individual components for all-cause mortality, but could not be assessed for cardiovascular disease mortality due to multicollinearity. Hyperglycaemia was the individual strongest parameter associated with mortality.\ud \u

Characterization of a CCD array for Bragg spectroscopy

The average pixel distance as well as the relative orientation of an array of 6 CCD detectors have been measured with accuracies of about 0.5 nm and 50 $\mu$rad, respectively. Such a precision satisfies the needs of modern crystal spectroscopy experiments in the field of exotic atoms and highly charged ions. Two different measurements have been performed by illuminating masks in front of the detector array by remote sources of radiation. In one case, an aluminum mask was irradiated with X-rays and in a second attempt, a nanometric quartz wafer was illuminated by a light bulb. Both methods gave consistent results with a smaller error for the optical method. In addition, the thermal expansion of the CCD detectors was characterized between -105 C and -40 C.Comment: Submitted to Review of Scientific Instrument

Printed Multi-Turn Loop Antennas for RF Biotelemetry

Printed multi-turn loop antennas have been designed for contactless powering of, and reception of radio signals transmitted by, surgically implantable biotelemetric sensor units operating at frequencies in the vicinity of 300 MHz

Illusions of gunk

The possibility of gunk has been used to argue against mereological nihilism. This paper explores two responses on the part of the microphysical mereological nihilist: (1) the contingency defence, which maintains that nihilism is true of the actual world; but that at other worlds, composition occurs; (2) the impossibility defence, which maintains that nihilism is necessary true, and so gunk worlds are impossible. The former is argued to be ultimately unstable; the latter faces the explanatorily burden of explaining the illusion that gunk is possible. It is argued that we can discharge this burden by focussing on the contingency of the microphysicalist aspect of microphysical mereological nihilism. The upshot is that gunk-based arguments against microphysical mereological nihilism can be resisted

Plains Tectonism on Venus: The Deformation Belts of Lavinia Planitia

High-resolution radar images from the Magellan spacecraft have revealed the first details of the morphology of the Lavinia Planitia region of Venus. A number of geologic units can be distinguished, including volcanic plains units with a range of ages. Transecting these plains over much of the Lavinia region are two types of generally orthogonal features that we interpret to be compressional wrinkle ridges and extensional grooves. The dominant tectonic features of Lavinia are broad elevated belts of intense deformation that transect the plains with complex geometry. They are many tens to a few hundred kilometers wide, as much as 1000 km long, and elevated hundreds of meters above the surrounding plains. Two classes of deformation belts are seen in the Lavinia region. “Ridge belts” are composed of parallel ridges, each a few hundred meters in elevation, that we interpret to be folds. Typical fold spacings are 5–10 km. “Fracture belts” are dominated instead by intense faulting, with faults in some instances paired to form narrow grabens. There is also some evidence for modest amounts of horizontal shear distributed across both ridge and fracture belts. Crosscutting relationships among the belts show there to be a range in belt ages. In western Lavinia in particular, many ridge and fracture belts appear to bear a relationship to the much smaller wrinkle ridges and grooves on the surrounding plains: Ridge morphology tends to dominate belts that lie more nearly parallel to local plains wrinkle ridges, and fracture morphology tends to dominate belts that lie more nearly parallel to local plains grooves. We use simple models to explore the formation of ridge and fracture belts. We show that convective motions in the mantle can couple to the crust to cause horizontal stresses of a magnitude sufficient to induce the formation of deformation belts like those observed in Lavinia. We also use the small-scale wavelengths of deformation observed within individual ridge belts to place an approximate lower limit on the venusian thermal gradient in the Lavinia region at the time of deformation

Ka-Band, Multi-Gigabit-Per-Second Transceiver

A document discusses a multi-Gigabit-per-second, Ka-band transceiver with a software-defined modem (SDM) capable of digitally encoding/decoding data and compensating for linear and nonlinear distortions in the end-to-end system, including the traveling-wave tube amplifier (TWTA). This innovation can increase data rates of space-to-ground communication links, and has potential application to NASA s future spacebased Earth observation system. The SDM incorporates an extended version of the industry-standard DVB-S2, and LDPC rate 9/10 FEC codec. The SDM supports a suite of waveforms, including QPSK, 8-PSK, 16-APSK, 32- APSK, 64-APSK, and 128-QAM. The Ka-band and TWTA deliver an output power on the order of 200 W with efficiency greater than 60%, and a passband of at least 3 GHz. The modem and the TWTA together enable a data rate of 20 Gbps with a low bit error rate (BER). The payload data rates for spacecraft in NASA s integrated space communications network can be increased by an order of magnitude (>10 ) over current state-of-practice. This innovation enhances the data rate by using bandwidth-efficient modulation techniques, which transmit a higher number of bits per Hertz of bandwidth than the currently used quadrature phase shift keying (QPSK) waveforms

Peak Satellite-to-Earth Data Rates Derived From Measurements of a 20 Gbps Bread-Board Modem

A prototype data link using a Ka-band space qualified, high efficiency 200 W TWT amplifier and a bread-board modem emulator were created to explore the feasibility of very high speed communications in satellite-to-earth applications. Experiments were conducted using a DVB-S2-like waveform with modifications to support up to 20 Gbps through the addition of 128-Quadrature Amplitude Modulation (QAM). Limited by the bandwidth of the amplifier, a constant peak symbol rate of 3.2 Giga-symbols/sec was selected and the modulation order was varied to explore what peak data rate might be supported by an RF link through this amplifier. Using 128-QAM, an implementation loss of 3 dB was observed at 20 Gbps, and the loss decreased as data rate or bandwidth were reduced. Building on this measured data, realistic link budget calculations were completed. Low-Earth orbit (LEO) missions based on this TWTA with reasonable hardware assumptions and antenna sizing are found to be bandwidth-limited, rather than power-limited, making the spectral efficiency of 9/10-rate encoded 128-QAM very attractive. Assuming a bandwidth allocation of 1 GHz, these computations indicate that low-Earth orbit vehicles could achieve data rates up to 5 Gbps-an order of magnitude beyond the current state-of-practice, yet still within the processing power of a current FPGA-based software-defined modem. The measured performance results and a description of the experimental setup are presented to support these conclusions

A habituation account of change detection in same/different judgments

We investigated the basis of change detection in a short-term priming task. In two experiments, participants were asked to indicate whether or not a target word was the same as a previously presented cue. Data from an experiment measuring magnetoencephalography failed to find different patterns for “same” and “different” responses, consistent with the claim that both arise from a common neural source, with response magnitude defining the difference between immediate novelty versus familiarity. In a behavioral experiment, we tested and confirmed the predictions of a habituation account of these judgments by comparing conditions in which the target, the cue, or neither was primed by its presentation in the previous trial. As predicted, cue-primed trials had faster response times, and target-primed trials had slower response times relative to the neither-primed baseline. These results were obtained irrespective of response repetition and stimulus–response contingencies. The behavioral and brain activity data support the view that detection of change drives performance in these tasks and that the underlying mechanism is neuronal habituation

Demonstration of Multi-Gbps Data Rates at Ka-Band Using Software-Defined Modem and Broadband High Power Amplifier for Space Communications

The paper presents the first ever research and experimental results regarding the combination of a software-defined multi-Gbps modem and a broadband high power space amplifier when tested with an extended form of the industry standard DVB-S2 and LDPC rate 9/10 FEC codec. The modem supports waveforms including QPSK, 8-PSK, 16-APSK, 32-APSK, 64-APSK, and 128-QAM. The broadband high power amplifier is a space qualified traveling-wave tube (TWT), which has a passband greater than 3 GHz at 33 GHz, output power of 200 W and efficiency greater than 60 percent. The modem and the TWTA together enabled an unprecedented data rate at 20 Gbps with low BER of 10(exp -9). The presented results include a plot of the received waveform constellation, BER vs. E(sub b)/N(sub 0) and implementation loss for each of the modulation types tested. The above results when included in an RF link budget analysis show that NASA s payload data rate can be increased by at least an order of magnitude (greater than 10X) over current state-of-practice, limited only by the spacecraft EIRP, ground receiver G/T, range, and available spectrum or bandwidth