Transport model for the propagation of partially coherent, partially polarized, polarization-gradient vector beams.

Recently we predicted and experimentally validated a new physical mechanism for altering the propagation path of a monochromatic beam [Opt. Express30, 38907 (2022)OPEXFF1094-408710.1364/OE.467678]. Specifically, we showed that by properly tailoring the spatial distribution of the linear state of polarization transverse to the direction of propagation, the beam followed a curved trajectory in free space. Here we extend the model to the partially coherent and partially polarized polychromatic case by redefining the beam amplitude, phase, and polarization angle as appropriate statistical quantities. In particular, the definition of polarization angle represents a fundamentally new quantity in modeling beam propagation and is shown to be consistent with recent works on energy and momentum flow. In the new model, the beam curvature matches that of our previous work in the fully coherent case but is predicted to vanish for an unpolarized, spatially incoherent beam. Simulated beam trajectories are shown for varying levels of initial partial coherence and for different polarization profiles. A new class of non-diffracting beams is also suggested by way of example.

Vector beam bending via a polarization gradient.

We propose, analyze and demonstrate experimentally an entirely new optical effect in which the centroid of a coherent optical beam can be designed to propagate along a curved trajectory in free space by tailoring the spatial distribution of linear polarization across the transverse beam profile. Specifically, a non-zero spatial gradient of second order or higher in the linear state of polarization is shown to cause the beam centroid to "accelerate" in the direction transverse to the direction of propagation. The effect is confirmed experimentally using spatial light modulation to create the distribution in linear polarization and then measuring the transverse location of the beam profile at varying propagation distances. The observed displacement of the beam centroid is shown to closely match the theory out to 34m propagation distance.

Trabecular bone score and its association with Cobb angle kyphosis in older men: a cross-sectional study for the Osteoporotic Fractures in Men (MrOS) Study.

Hyperkyphosis (HK), or accentuated forward spinal curvature, commonly affects older people, although its causes are not completely understood. We tested whether a measure of bone quality, trabecular bone score (TBS), is associated with HK in 1997 older men, and determined that men with degraded TBS were more likely to have HK. INTRODUCTION: While vertebral fractures and low bone mineral density (BMD) contribute to kyphosis progression, it is unknown whether the trabecular bone score (TBS) may provide additional information on bone quality that could influence the degree of kyphosis. We hypothesized that degraded TBS would be associated with hyperkyphosis (HK) defined as a Cobb angle > 50°. METHODS: Using data from 1997 participants of the Osteoporotic Fractures in Men (MrOS) Study who had baseline TBS and Cobb angle kyphosis measured, we investigated whether men with degraded TBS were more likely to be hyperkyphotic, even after adjustment for BMD and prevalent vertebral fractures. RESULTS: Men were an average age of 74 ± 6 (mean ± SD) years with a mean kyphosis angle of 38.6 ± 11.5°, 295 (15%) were classified as hyperkyphotic, and 416 (21%) had degraded TBS. Compared with men with TBS > 1.2, men with degraded TBS were more likely to have HK (OR: 1.47, 95% CI: 1.06-2.06, p = 0.02) after adjusting for age, clinic, race, BMI, hip BMD, and prevalent vertebral fracture. If spine instead of hip BMD was included in the model, the odds ratio decreased to 1.35 (95% CI: 0.97-1.89, p = 0.08). CONCLUSIONS: Older men with degraded TBS are more likely to have HK not explained by underlying vertebral fractures.

Jupiter's X-Ray and UV Dark Polar Region.

We present 14 simultaneous Chandra X-ray Observatory (CXO)-Hubble Space Telescope (HST) observations of Jupiter's Northern X-ray and ultraviolet (UV) aurorae from 2016 to 2019. Despite the variety of dynamic UV and X-ray auroral structures, one region is conspicuous by its persistent absence of emission: the dark polar region (DPR). Previous HST observations have shown that very little UV emission is produced by the DPR. We find that the DPR also produces very few X-ray photons. For all 14 observations, the low level of X-ray emission from the DPR is consistent (within 2-standard deviations) with scattered solar emission and/or photons spread by Chandra's Point Spread Function from known X-ray-bright regions. We therefore conclude that for these 14 observations the DPR produced no statistically significant detectable X-ray signature.

Soil erosion response to land use change in a mountainous rural area of Son La Province of Vietnam.

This study investigated the changes in soil erosion associated with land use change from 2000 to 2020 in a mountainous rural area. Land use change was detected using Landsat images and soil erosion was estimated using the revised universal soil loss equation (RUSLE). The results show that deforestation and fallow cultivation caused substantial soil loss, whereas conversion from uncultivated land to cropland reduced soil erosion. A conversion from 711 ha cropland and 234 ha forestland to uncultivated land increased the average soil loss from 17 ton·ha-1·year-1 to 42 ton·ha-1·year-1 and the area of eroded soil at the very high level from 276 to 1058 ha between 2000 and 2010. In contrast, a wide expansion of cropland from 637 ha uncultivated land decreased the average soil loss from 42 ton·ha-1·year-1 to 32 ton·ha-1·year-1 and the area of eroded soil at the very high level from 1058 to 690 ha between 2010 and 2020. We suggest management measures such as forest protection, afforestation, reforestation, fruit tree development, and soil erosion control practices in coffee and maize cultivation to reduce soil erosion.

Kyphosis and 3-year fall risk in community-dwelling older men.

Hyperkyhosis is thought to be a fall risk factor in older adults. This large study of older men found that fall risk increased with greater kyphosis measured with the blocks method, but did not find an association between kyphosis and falls when measured by the commonly used the Cobb angle method. INTRODUCTION: Research suggests an association between hyperkyphosis and falls in community-dwelling older adults, though this has not been investigated within large, population-based studies. This study sought to determine whether two measures of kyphosis prospectively predict fall risk over 3 years among older men. METHODS: Within the Osteoporotic Fractures in Men Study (MrOS), we conducted two 3-year prospective studies of 2346 and 2928 men. The first group had kyphosis measured by the Cobb angle at visit 1, while the second group had kyphosis assessed with the blocks method at visit 3; both groups then self-reported falls tri-annually for 3 years. Poisson regression with GEE was used to obtain relative risks (RR) of falls. RESULTS: The fall rates over 3 years were 651/1000 person-years among the visit 1 sample (mean age 74 ± 6 years) and 839/1000 person-years among the visit 3 sample (mean age 79 ± 5 years). In adjusted models of the visit 3 sample, the risk of falls was increased by 12% for each standard deviation increase (1.4 blocks) in the number of blocks required to achieve a neutral head and neck position (RR = 1.12, 95% CI = 1.06, 1.18). The Cobb angle was not associated with falls in the visit 1 sample. CONCLUSIONS: Although the Cobb angle did not predict falls in community-dwelling older men over 3 years, the blocks method of measuring kyphosis was predictive of falls in this population. This difference could be due to the Cobb angle's focus on thoracic kyphosis, whereas the blocks method may additionally capture abnormal cervical spine curvature.

Learned linear models for detecting watercraft in a maritime environment.

This work provides a new, to the best of our knowledge, approach to constructing linear models for object detection in a scene. Specifically, we use representative training data in order to estimate the parameters describing a generalized wavelet model for the express purpose of detecting the presence of maritime targets in a scene. The parameter estimates are taken as those that maximize the probability of detecting the targets for a fixed probability of false alarm. The approach is then demonstrated on a database of short-wave infrared imagery containing various watercraft. Results are then compared to some of the more standard wavelet bases used in detection applications.

Kyphosis and incident falls among community-dwelling older adults.

Hyperkyphosis commonly affects older persons and is associated with morbidity and mortality. Many have hypothesized that hyperkyphosis increases fall risk. Within this prospective study of older adults, kyphosis was significantly associated with incident falls over 1 year. Measures of hyperkyphosis could enhance falls risk assessments during primary care office visits. INTRODUCTION: To determine the association between four measures of kyphosis and incident and injurious falls in older persons. METHODS: Community-dwelling adults aged 65 and older (n = 72) residing in southern California were invited to participate in a prospective cohort study. Participants had kyphosis assessed four ways. Two standing measures included a flexicurve ruler placed against the back to derive a kyphotic index and the Debrunner kyphometer, a protractor used to measure the kyphotic angle in degrees. Two lying measures included the blocks method (number of 1.7 cm blocks needed to achieve a neutral head position while lying supine) and traditional Cobb angle calculation derived from DXA based lateral vertebral assessment. Baseline demographic, clinical, and other health information (including a timed up and go (TUG) test) were assessed at a clinic visit. Participants were followed monthly through email or postcard for 1 year, with falls outcomes confirmed through telephone interview. RESULTS: Mean age was 77.8 (± 7.1) among the 52 women and 20 men. Over 12 months, 64% of participants experienced at least one incident fall and 35% experienced an injurious fall. Each standard deviation increase in kyphosis resulted in more than doubling the adjusted odds of an incident fall, even after adjusting for TUG. Odds of injurious falls were less consistent across measures; after adjusting for TUG, only the blocks method was associated with injurious falls. CONCLUSIONS: Each kyphosis measure was independently associated with incident falls. Findings were inconsistent for injurious falls; the blocks measure suggested the strongest association. If these findings are replicated, the blocks measure could be incorporated into office visits as a quick and efficient tool to identify patients at increased fall risk.

Distribution of splice loss in single mode optical fiber.

This work investigates a probabilistic model for splice loss in single mode optical fibers. We derive the probability density function for loss values as a function of lateral and angular misalignment. We then use observed data to estimate these model parameters; both Bayesian and maximum likelihood estimation procedures are described. These estimates can then be used to provide an indication of the relative importance of various loss mechanisms. Alternatively, if one is given values for maximum lateral and angular misalignment, our results allow for predictions of expected distribution of loss values. An overall goal of this paper is to demonstrate that, beyond the mean and variance of splice loss, there is significant information in the shape of the distribution of values. A second goal is to understand the trade-off between the number of splice loss measurements and the confidence in estimates of parameters in the splice loss model.

Transport-based model for turbulence-corrupted imagery.

A new model for turbulence-corrupted imagery is proposed based on the theory of optimal mass transport. By describing the relationship between photon density and the phase of the traveling wave, and combining it with a least action principle, the model suggests a new class of methods for approximately recovering the solution of the photon density flow created by a turbulent atmosphere. Both coherent and incoherent imagery are used to validate and compare the model to other methods typically used to describe this type of data. Given its superior performance in describing experimental data, the new model suggests new algorithms for a variety of atmospheric imaging and wave propagation applications.

Associations between physical activity and BMI, body fatness, and visceral adiposity in overweight or obese Latino and non-Latino adults.

BACKGROUND/OBJECTIVES: Although several studies have reported associations between moderate to vigorous physical activity (MVPA), body fatness and visceral adipose tissue (VAT), the extent to which associations differ among Latinos and non-Latinos remains unclear. This study evaluated the associations between body composition and MVPA in Latino and non-Latino adults. SUBJECTS/METHODS: An exploratory, cross-sectional analysis was conducted using baseline data collected from 298 overweight adults enrolled in a 12-month randomized controlled trial that tested the efficacy of text messaging to improve weight loss. MVPA, body fatness and VAT were assessed by waist-worn accelerometry, dual-energy x-ray absorptiometry (DXA), and DXA-derived software (GE CoreScan GE, Madison, WI, USA), respectively. Participants with <5 days of accelerometry data or missing DXA data were excluded; 236 participants had complete data. Multivariable linear regression assessed associations between body composition and MVPA per day, defined as time in MVPA, bouts of MVPA (time per bout ⩾10 min), non-bouts of MVPA (time per bout <10 min) and meeting the 150-min MVPA guideline. The modifying influence of ethnicity was modeled with a multiplicative interaction term. RESULTS: The interaction between ethnicity and MVPA in predicting percent body fat was significant (P=0.01, 95% confidence interval (CI) (0.58, 4.43)) such that a given increase in MVPA was associated with a greater decline in total body fat in non-Latinos compared with Latinos (adjusted for age, sex and accelerometer wear time). There was no interaction between ethnicity and MVPA in predicting VAT (g) (P=0.78, 95% CI (-205.74, 273.17)) and body mass index (BMI) (P=0.18, 95% CI (-0.49, 2.26)). CONCLUSIONS: An increase in MVPA was associated with a larger decrease in body fat, but neither BMI nor VAT, in non-Latinos compared with Latinos. This suggests that changes in VAT and BMI in response to MVPA may be less influenced by ethnicity than is total body fatness.

Juno-UVS approach observations of Jupiter's auroras.

Juno ultraviolet spectrograph (UVS) observations of Jupiter's aurora obtained during approach are presented. Prior to the bow shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions are expected to be controlled or modified by local solar wind conditions. Here we compare synoptic Juno-UVS observations of Jupiter's auroral emissions, acquired during 3-29 June 2016, with in situ solar wind observations, and related Jupiter observations from Earth. Four large auroral brightening events are evident in the synoptic data, in which the total emitted auroral power increases by a factor of 3-4 for a few hours. Only one of these brightening events correlates well with large transient increases in solar wind ram pressure. The brightening events which are not associated with the solar wind generally have a risetime of ~2 h and a decay time of ~5 h.

Experimental infrared point-source detection using an iterative generalized likelihood ratio test algorithm.

This work documents the performance of a recently proposed generalized likelihood ratio test (GLRT) algorithm in detecting thermal point-source targets against a sky background. A calibrated source is placed above the horizon at various ranges and then imaged using a mid-wave infrared camera. The proposed algorithm combines a so-called "shrinkage" estimator of the background covariance matrix and an iterative maximum likelihood estimator of the point-source parameters to produce the GLRT statistic. It is clearly shown that the proposed approach results in better detection performance than either standard energy detection or previous implementations of the GLRT detector.

The effect of age on fitness among female firefighters.

BACKGROUND: The physical demands of firefighting require both cardiovascular and muscular fitness, which both decline with age. While much has been published on age-related changes among male firefighters (FFs), data on female FFs are lacking. AIMS: To describe cardiorespiratory fitness (CRF) and muscular fitness in a sample of female career FFs ranging in age from 25 to 60 years and determine whether ageing affects their achievement of the current recommended professional CRF standards of 12 metabolic equivalents (METs). METHODS: Data were collected on female FFs over an 11-year period. A cross-sectional analysis using one-way analysis of variance with Bonferroni post hoc comparisons was used to compare age groups. RESULTS: There were 96 study participants. Maximum METs was significantly higher (P < 0.01) in the 25- to 34-year age group (14.6 ± 2.1) compared with the 35-44 age group (12.9 ± 2.0 METs) and the 45-54 age group (12.2 ± 1.8 METs, P < 0.001). While the mean values of all measured age groups met or exceeded the 12-MET profession standard, as many as one-third of FFs <45 years of age and 43% of FFs >45 years of age fell below the benchmark of 12 METs. Muscular fitness as measured by maximum number of push-ups, sit-ups and back endurance was not significantly different between age groups. CONCLUSIONS: Fire departments should recognize and take steps to ensure all female FFs maintain CRF and muscular fitness throughout their careers.

Correlations among four measures of thoracic kyphosis in older adults.

SUMMARY: There are many ways to measure thoracic kyphosis ranging from simple clinical to more complex assessments. We evaluated the correlation among four commonly used kyphosis measures: Cobb angle, Debrunner kyphometer, kyphotic index, and the blocks method. Each measure was correlated with the others, confirming high clinical and research applicability. INTRODUCTION: The purpose of this study was to assess the associations among four commonly used measures of thoracic kyphosis in older adults. METHODS: Seventy two men and women aged 65-96 were recruited from the San Diego community. Four kyphosis measures were assessed in the same person during a baseline clinic visit. Two measures were done in the lying (L) and two in the standing (ST) position: (1) Cobb angle calculated from dual X-Ray absorptiometry (DXA) images (L), (2) Debrunner kyphometer (DK) angle measured by a protractor (ST), (3) kyphotic index (KI) calculated using an architect's flexicurve ruler (ST), and (4) the blocks method involving counting the number of 1.7 cm-thick blocks required to achieve a neutral head position while lying flat on the DXA table (L). Spearman rank correlation coefficients were used to determine the strength of the association between each kyphosis measure. RESULTS: Using the Cobb angle as the gold standard, the blocks method demonstrated the lowest correlation (r(s) = 0.63, p < 0.0001), the Debrunner method had a moderate correlation (r(s) = 0.65, p < 0.0001), and the kyphotic index had the highest correlation (r(s) = 0.68, p < 0.0001). The correlation was strongest between the kyphotic index and the Debrunner kyphometer (r(s) = 0.76, p < 0.0001). CONCLUSION: In older men and women, all four measures of thoracic kyphosis were significantly correlated with each other, whether assessed in the lying or standing position. Thus, any of these measures demonstrate both potential clinical and research utility.

A study of molecular adsorption of a cationic surfactant on complex surfaces with atomic force microscopy.

The study of molecular adsorption on solid surfaces is of broad interest. However, so far the study has been restricted to idealized flat smooth rigid surfaces which are rarely the case in real world applications. Here we describe a study of molecular adsorption on a complex surface of the submicron fibers of a fibrous membrane of regenerated cellulose in aqueous media. We use a cationic surfactant, cetyltrimethylammonium chloride (CTAC), as the adsorbing molecule. We study the equilibrium adsorption of CTAC molecules on the same area of the fibers by sequentially immersing the membrane in pure water, 1 mM and then a 20 mM solution of CTAC. Atomic force microscopy (AFM) is applied to study the adsorption. The force-volume mode is used to record the force-deformation curves of the adsorbed molecules on the fiber surface. We suggest a model to separate the forces due to the adsorbed molecules from the elastic deformation of the fiber. Interestingly, knowledge of the surface geometry is not required in this model provided the surface is made of elastically homogeneous material. Different models are investigated to estimate the amount of the adsorbed molecules based on the obtained force curves. The exponential steric repulsion model fits the force data the best. The amount of the adsorbed surfactant molecules and its dependence on the concentration are found to be reasonable compared to the data previously measured by means of Raman scattering done on a flat surface of silica.

Analytical expression for pixel-averaged point sources as observed by a focal plane array.

A closed-form expression is derived for pixel-averaged point source signals as observed by an imaging array. Obtaining this solution requires the probability distribution of squared Euclidean distances in two dimensions when the end points are confined to a uniformly spaced square domain. The derivation and associated expression are provided.

Range performance of the DARPA AWARE wide field-of-view visible imager.

In a prior paper, we described a new imaging architecture that addresses the need for wide field-of-view imaging combined with the resolution required to identify targets at long range. Over the last two years substantive improvements have been made to the system, both in terms of the size, weight, and power of the camera as well as to the optics and data management software. The result is an overall improvement in system performance, which we demonstrate via a maritime target identification experiment.

Utility of ¹8fluoro-deoxyglucose positron emission tomography for prognosis and response assessments in a phase 2 study of romidepsin in patients with relapsed or refractory peripheral T-cell lymphoma.

BACKGROUND: For patients with peripheral T-cell lymphoma (PTCL), the value of (18)fluoro-deoxyglucose positron emission tomography (FDG-PET) scans for assessing prognosis and response to treatment remains unclear. The utility of FDG-PET, in addition to conventional radiology, was examined as a planned exploratory end point in the pivotal phase 2 trial of romidepsin for the treatment of relapsed/refractory PTCL. PATIENTS AND METHODS: Patients received romidepsin at a dose of 14 mg/m(2) on days 1, 8, and 15 of 28-day cycles. The primary end point was the rate of confirmed/unconfirmed complete response (CR/CRu) as assessed by International Workshop Criteria (IWC) using conventional radiology. For the exploratory PET end point, patients with at least baseline FDG-PET scans were assessed by IWC + PET criteria. RESULTS: Of 130 patients, 110 had baseline FDG-PET scans, and 105 were PET positive at baseline. The use of IWC + PET criteria increased the objective response rate to 30% compared with 26% by conventional radiology. Durations of response were well differentiated by both conventional radiology response criteria [CR/CRu versus partial response (PR), P = 0.0001] and PET status (negative versus positive, P < 0.0001). Patients who achieved CR/CRu had prolonged progression-free survival (PFS, median 25.9 months) compared with other response groups (P = 0.0007). Patients who achieved PR or stable disease (SD) had similar PFS (median 7.2 and 6.3 months, respectively, P = 0.6427). When grouping PR and SD patients by PET status, patients with PET-negative versus PET-positive disease had a median PFS of 18.2 versus 7.1 months (P = 0.0923). CONCLUSIONS: Routine use of FDG-PET does not obviate conventional staging, but may aid in determining prognosis and refine response assessments for patients with PTCL, particularly for those who do not achieve CR/CRu by conventional staging. The optimal way to incorporate FDG-PET scans for patients with PTCL remains to be determined. TRIAL REGISTRATION: NCT00426764.