Implications of Polarized Pupil Degradation Due to Focal Shifts in Dynamically Ranged Rayleigh Beacons

A dynamically ranged pulsed Rayleigh beacon using sensed wavefronts across a system’s pupil plane is proposed for tomographic quantification of the atmospheric turbulence strength. This method relies on relaying light from a telescope system’s pupil plane to a wavefront sensor and having precise control of the light-blocking mechanisms to filter out scattered light from the unwanted scattering regions along the propagation path. To accomplish this, we tested and incorporated design features into the sensing system that we believe, to the best of our knowledge, are unique. Dynamically changing the range of the beacon source created focal shifts along the optical axis in the telescope sensing system. This effect induced polarization degradation in the optical pupil. As a result, polarization nonuniformity within the Pockels cell resulted in light leakages that corrupted the sensed data signals. To mitigate this unwanted effect, an analysis of the polarization pupil had to be completed for the range of possible Rayleigh beacon source distances, relating the change in polarization to the ability of a Pockels cell to function as an optical shutter. Based on the resultant polarization pupil analysis, careful design of the light relay architecture of the sensing system was necessary to properly capture sensed wavefront data from a series of intended ranges. Results are presented for the engineering design of the Turbulence and Aerosol Research Dynamic Interrogation System sensing system showing the choices made within the trade space and how those choices were made based on an analysis of the polarization pupil. Based on what we learned, recommendations are made to effectively implement a polarization-based Pockels cell shutter system as part of a dynamically ranged Rayleigh beacon system

Action principles, restoration of BRS symmetry and the renormalization group equation for chiral non-Abelian gauge theories in dimensional renormalization with a non-anticommuting γ5\gamma_5

The one-loop renormalization of a general chiral gauge theory without scalar and Majorana fields is fully worked out within Breitenlohner and Maison dimensional renormalization scheme. The coefficients of the anomalous terms introduced in the Slavnov-Taylor equations by the minimal subtraction algorithm are calculated and the asymmetric counterterms needed to restore the BRS symmetry, if the anomaly cancellation conditions are met, are computed. The renormalization group equation and its coefficients are worked out in the anomaly free case. The computations draw heavily from the existence of action principles and BRS cohomology theory.Comment: 86 pages, 14 figures, one table, plane te

Estimating Turbulence Distribution over a Heterogeneous Path Using Time‐lapse Imagery from Dual Cameras

Knowledge of turbulence distribution along an experimental path can help in effective turbulence compensation and mitigation. Although scintillometers are traditionally used to measure the strength of turbulence, they provide a path-integrated measurement and have limited operational ranges. A technique to profile turbulence using time-lapse imagery of a distant target from spatially separated cameras is presented here. The method uses the turbulence induced differential motion between pairs of point features on a target, sensed at a single camera and between cameras to extract turbulence distribution along the path. The method is successfully demonstrated on a 511 m almost horizontal path going over half concrete and half grass. An array of Light-Emitting Diodes (LEDs) of non-uniform separation is imaged by a pair of cameras, and the extracted turbulence profiles are validated against measurements from 3D sonic anemometers placed along the path. A short-range experiment with a heat source to create local turbulence spike gives good results as well. Because the method is phase-based, it does not suffer from saturation issues and can potentially be applied over long ranges. Although in the present work, a cooperative target has been used, the technique can be used with non-cooperative targets. Application of the technique to images collected over slant paths with elevated targets can aid in understanding the altitude dependence of turbulence in the surface layer

A latent class analysis of cannabis use products in a general population sample of adolescents and their association with paranoia, hallucinations, cognitive disorganisation and grandiosity

Adolescents have access to a wide range of cannabis products with patterns of use becoming increasingly diverse. This study aimed to identify subgroups of adolescents in the general population who use similar types of cannabis and their association with psychotic experiences. Data on cannabis use were obtained from 467 adolescents aged between 16 and 17 years. Latent class analysis (LCA) identified groups of adolescents based on the type of cannabis used in the past 12 months. Univariate analysis explored differences in socio-demographics, substance use and mental health symptoms between groups. Multivariate analysis examined associations between class membership and psychotic experiences controlling for frequency and amount of cannabis. Finally, we explored the association between motives for cannabis and class membership using multi-nominal logistic regression. LCA identified 3 classes of adolescents: (i) herbal only (47.9%); (ii) skunk only (20.8%) and (3) mixed use (31.3%). Relative to non-users, skunk only use was associated with a 2-fold increase in paranoia (OR = 2.45, 95% CI = 1.29-4.63), along with, sleep disturbance and anxiety. Monthly cannabis use and consuming 2 or more joints on one occasion was associated with a 2-fold increase in hallucinations (OR = 2.2; 95% CI = 1.0-4.8 and OR = 1.9; 95% CI = 1.2-3.2), but did not reach the Bonferroni corrected p-value. Expansion and conformity motives differentiated the mixed cannabis class from the herbal only class. The findings suggest that different subgroups of cannabis users exist in adolescence as defined by the type of cannabis consumed and are differentially related to psychotic experiences and motives for use.</p

A latent class analysis of cannabis use products in a general population sample of adolescents and their association with paranoia, hallucinations, cognitive disorganisation and grandiosity

Adolescents have access to a wide range of cannabis products with patterns of use becoming increasingly diverse. This study aimed to identify subgroups of adolescents in the general population who use similar types of cannabis and their association with psychotic experiences. Data on cannabis use were obtained from 467 adolescents aged between 16 and 17 years. Latent class analysis (LCA) identified groups of adolescents based on the type of cannabis used in the past 12 months. Univariate analysis explored differences in socio-demographics, substance use and mental health symptoms between groups. Multivariate analysis examined associations between class membership and psychotic experiences controlling for frequency and amount of cannabis. Finally, we explored the association between motives for cannabis and class membership using multi-nominal logistic regression. LCA identified 3 classes of adolescents: (i) herbal only (47.9%); (ii) skunk only (20.8%) and (3) mixed use (31.3%). Relative to non-users, skunk only use was associated with a 2-fold increase in paranoia (OR = 2.45, 95% CI = 1.29-4.63), along with, sleep disturbance and anxiety. Monthly cannabis use and consuming 2 or more joints on one occasion was associated with a 2-fold increase in hallucinations (OR = 2.2; 95% CI = 1.0-4.8 and OR = 1.9; 95% CI = 1.2-3.2), but did not reach the Bonferroni corrected p-value. Expansion and conformity motives differentiated the mixed cannabis class from the herbal only class. The findings suggest that different subgroups of cannabis users exist in adolescence as defined by the type of cannabis consumed and are differentially related to psychotic experiences and motives for use.</p

Equatorial locations of water on Mars: Improved resolution maps based on Mars Odyssey Neutron Spectrometer data

We present a map of the near subsurface hydrogen distribution on Mars, based on epithermal neutron data from the Mars Odyssey Neutron Spectrometer. The map’s spatial resolution is approximately improved two-fold via a new form of the pixon image reconstruction technique. We discover hydrogen-rich mineralogy far from the poles, including  ∼10 wt.% water equivalent hydrogen (WEH) on the flanks of the Tharsis Montes and  >40 wt.% WEH at the Medusae Fossae Formation (MFF). The high WEH abundance at the MFF implies the presence of bulk water ice. This supports the hypothesis of recent periods of high orbital obliquity during which water ice was stable on the surface. We find the young undivided channel system material in southern Elysium Planitia to be distinct from its surroundings and exceptionally dry; there is no evidence of hydration at the location in Elysium Planitia suggested to contain a buried water ice sea. Finally, we find that the sites of recurring slope lineae (RSL) do not correlate with subsurface hydration. This implies that RSL are not fed by large, near-subsurface aquifers, but are instead the result of either small ( < 120 km diameter) aquifers, deliquescence of perchlorate and chlorate salts or dry, granular flows

The Modification of Spousal Interaction After Aphasia

Researchers have investigated the ways spouses collaboratively overcome the communication barriers they face subsequent to aphasia in one of the partners (e.g., Oelschlaeger & Damico, 2003). These studies have demonstrated ways that the interactional dynamic is employed to re-establish social action after aphasia. However, little has been done to determine how spousal dyads created these modifications. This study was undertaken to investigate how the evolution of the described adaptations to conversation within spousal dyads was accomplished

Limit Cycles in Four Dimensions

We present an example of a limit cycle, i.e., a recurrent flow-line of the beta-function vector field, in a unitary four-dimensional gauge theory. We thus prove that beta functions of four-dimensional gauge theories do not produce gradient flows. The limit cycle is established in perturbation theory with a three-loop calculation which we describe in detail.Comment: 12 pages, 1 figure. Significant revision of the interpretation of our result. Improved description of three-loop calculatio