Motion Segmentation Algorithm using Spectral Framework

This paper presents a new motion segmentation method using iterative maximum likelihood framework. The method consists of two steps. In the first step, motion regions are detected and motion vectors are computed for these detected regions. In the second step, a similarity matrix is computed from the motion vectors and motion segmentation is done using maximum likelihood method. The method has been tested using real world motion sequences and is found to give very low error rate and it also detects the slow moving objects.Defence Science Journal, 2010, 60(1), pp.39-47, DOI:http://dx.doi.org/10.14429/dsj.60.10

The Perceived Impact of Parental Depression on the Narrative Construction of Personal Identity: Reflections from Emerging Adults

This paper presents a narrative analysis of emerging adults’ perceptions of the impact of parental depression on themselves as they reflected back on their lives in their natal home. Archived interview narratives were analyzed from sixteen respondents from a preventive intervention study of depression in families. The perceptions of parental depression and the perceived impact of parental depression were found to fall into five perspectives: resistance (no impact), negativity (being disadvantaged), ambivalent perspectives (disadvantaged but also sensitized), acceptance (reconciling with loss), and, compassion (sensitivity and caregiving). The findings from the narratives indicated that the perceived impacts of parental depression spanned a spectrum of responses, not all of which were negative. Emerging adults with their own history of depression reported a more resistant or negative perceived impact of parental depression, and more boys than girls narrated perceived negative impacts of parental depression on the self. These perspectives on parental depression derived from the narratives offer clinicians and family therapists a means of understanding the impact of depression on emerging adults’ sense of self. Implications of language usage, such as tense and coherence, are also discussed

Turbulent flow at 190 m height above London during 2006-2008: A climatology and the applicability of similarity theory

Flow and turbulence above urban terrain is more complex than above rural terrain, due to the different momentum and heat transfer characteristics that are affected by the presence of buildings (e.g. pressure variations around buildings). The applicability of similarity theory (as developed over rural terrain) is tested using observations of flow from a sonic anemometer located at 190.3 m height in London, U.K. using about 6500 h of data. Turbulence statistics—dimensionless wind speed and temperature, standard deviations and correlation coefficients for momentum and heat transfer—were analysed in three ways. First, turbulence statistics were plotted as a function only of a local stability parameter z/Λ (where Λ is the local Obukhov length and z is the height above ground); the σ_i/u_* values (i = u, v, w) for neutral conditions are 2.3, 1.85 and 1.35 respectively, similar to canonical values. Second, analysis of urban mixed-layer formulations during daytime convective conditions over London was undertaken, showing that atmospheric turbulence at high altitude over large cities might not behave dissimilarly from that over rural terrain. Third, correlation coefficients for heat and momentum were analyzed with respect to local stability. The results give confidence in using the framework of local similarity for turbulence measured over London, and perhaps other cities. However, the following caveats for our data are worth noting: (i) the terrain is reasonably flat, (ii) building heights vary little over a large area, and (iii) the sensor height is above the mean roughness sublayer depth

Tracking momentary experience in the evaluation of arts-on-prescription services: Using mood changes during art workshops to predict global wellbeing change

Aims: To measure the immediate impact of participating in arts-on-prescription workshops on multiple dimensions of mood and to evaluate whether improvement in mood is a mechanism for change, predicting improvements in global wellbeing before and after participation in arts-on-prescription programmes. Methods: The evaluation drew upon the experience sampling method, asking participants to complete a six-item mood questionnaire at the beginning and end of each workshop in a 12-week-long arts-on-prescription programme. Participants also completed a measure of global wellbeing at the beginning and end of the programme. Results: Multilevel modelling was used to test hypotheses since the data were hierarchical (with 1491 mood reports nested within 66 participants). There was a significant improvement in global wellbeing across participation in the arts-on-prescription programme. After each art workshop there was a significant increase on all dimensions of mood: hedonic tone (contentment); tense arousal (calmness); and energetic arousal (alertness). There was also a significant improvement in these dimensions of mood, over time, upon arrival at the art workshops each week. Furthermore, reduction in tense arousal after art workshops significantly predicted changes in global wellbeing. Conclusion: The findings suggest that a reduction in tense arousal (feeling less nervous, anxious and stressed) is a crucial component of arts-on-prescription services and make a direct link between experiences during art workshops and changes in global wellbeing for the first time. This strengthens the evidence base for arts-on-prescription and suggests that tracking experience across interventions is a useful evaluation tool, with much potential

A comparison of methods for estimating Reynolds stress from ADCP measurements in wavy environments

Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 28 (2011): 1539–1553, doi:10.1175/JTECH-D-11-00001.1.Turbulent Reynolds stresses are now routinely estimated from acoustic Doppler current profiler (ADCP) measurements in estuaries and tidal channels using the variance method, yet biases due to surface gravity waves limit its use in the coastal ocean. Recent modifications to this method, including spatially filtering velocities to isolate the turbulence from wave velocities and fitting a cospectral model to the below-wave band cospectra, have been used to remove this bias. Individually, each modification performed well for the published test datasets, but a comparative analysis over the range of conditions in the coastal ocean has not yet been performed. This work uses ADCP velocity measurements from five previously published coastal ocean and estuarine datasets, which span a range of wave and current conditions as well as instrument configurations, to directly compare methods for estimating stresses in the presence of waves. The computed stresses from each were compared to bottom stress estimates from a quadratic drag law and, where available, estimates of wind stress. These comparisons, along with an analysis of the cospectra, indicated that spectral fitting performs well when the wave climate is wide-banded and/or multidirectional as well as when instrument noise is high. In contrast, spatial filtering performs better when waves are narrow-banded, low frequency, and when wave orbital velocities are strong relative to currents. However, as spatial filtering uses vertically separated velocity bins to remove the wave bias, spectral fitting is able to resolve stresses over a larger fraction of the water column.J. Rosman acknowledges funding from the National Science Foundation (OCE-1061108)

Provider confidence in counseling preconception, pregnant, and postpartum patients regarding COVID‐19 vaccination: A cross‐sectional survey study

Background and Aims Healthcare provider counseling surrounding COVID‐19 vaccine in pregnancy and lactation is essential to vaccination uptake in this population; however, provider knowledge and confidence are not well characterized. We aimed to assess knowledge and confidence in COVID‐19 vaccine counseling among practitioners who provide care to pregnant persons and to describe factors associated with confidence in counseling. Methods A web‐based anonymous survey was distributed via email to a cross‐sectional convenience sample of Obstetrics and Gynecology, Primary Care, and Internal Medicine faculty at three hospitals in a single healthcare network in Massachusetts, United States. Individual demographics and institution‐specific variables were included in the survey along with questions assessing both attitudes toward COVID‐19 illness and confidence in counseling regarding the use of the vaccine in pregnancy. Results Almost all providers (151, 98.1%) reported that they received a COVID‐19 vaccine, and most (111, 72.1%) reported that they believe the benefits of the vaccine in pregnancy outweigh the risks. Forty‐one (26.6%) reported feeling very confident in counseling patients who primarily speak English about the evidence for messenger ribonucleic acid vaccination in pregnancy, and 36 (23%) reported feeling very confident in counseling patients who are not primarily English‐speaking. Forty‐three providers (28.1%) expressed strong confidence in their comfort talking to individuals with vaccine hesitancy based on historic and continued racism and systemic injustices. The sources that survey respondents most used to find information regarding COVID‐19 vaccination in pregnancy were the Centers for Disease Control (112, 74.2%), hospital‐specific resources (94, 62.3%), and the American College of Obstetricians and Gynecologists (82, 54.3%). Conclusion Ensuring that providers feel comfortable bridging the gap between their belief that the vaccine is beneficial for pregnant patients and their comfort with holding conversations with patients regarding vaccination is paramount to ensure equitable access to vaccines for pregnant patients

Effect of large-scale coherent structures on turbulent convection

We study an effect of large-scale coherent structures on global properties of turbulent convection in laboratory experiments in air flow in a rectangular chamber with aspect ratios $A \approx 2$ and $A\approx 4$ (with the Rayleigh numbers varying in the range from $5 \times 10^6$ to $10^8$). The large-scale coherent structures comprise the one-cell and two-cell flow patterns. We found that a main contribution to the turbulence kinetic energy production in turbulent convection with large-scale coherent structures is due to the non-uniform large-scale motions. Turbulence in large Rayleigh number convection with coherent structures is produced by shear, rather than by buoyancy. We determined the scalings of global parameters (e.g., the production and dissipation of turbulent kinetic energy, the turbulent velocity and integral turbulent scale, the large-scale shear, etc.) of turbulent convection versus the temperature difference between the bottom and the top walls of the chamber. These scalings are in an agreement with our theoretical predictions. We demonstrated that the degree of inhomogeneity of the turbulent convection with large-scale coherent structures is small.Comment: 10 pages, 12 figures, REVTEX

Field Measurements of Terrestrial and Martian Dust Devils

Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types