Robust drift-free bit-rate preserving H.264 watermarking

International audienceThis paper presents a novel method for open-loop watermarking of H.264/AVC bitstreams. Existing watermarking algorithms designed for previous encoders, such as MPEG-2 cannot be directly applied to H.264/AVC, as H.264/AVC implements numerous new features that were not considered in previous coders. In contrast to previous watermarking techniques for H.264/AVC bitstreams, which embed the information after the reconstruction loop and perform drift compensation, we propose a completely new intra-drift-free watermarking algorithm. The major design goals of this novel H.264/AVC watermarking algorithm are runtime-efficiency, high perceptual quality, (almost) no bit-rate increase and robustness to re-compression. The watermark is extremely runtime-efficiently embedded in the compressed domain after the reconstruction loop, i.e., all prediction results are reused. Nevertheless, intra-drift is avoided, as the watermark is embedded in such a way that the pixels used for the prediction are kept unchanged. Thus, there is no drift as the pixels being used in the intra-prediction process of H.264/AVC are not modified. For watermark detection, we use a two-stage cross-correlation. Our simulation results confirm that the proposed technique is robust against re-encoding and shows a negligible impact on both the bit-rate and the visual quality

Evolution of Mass Outflow in Protostars

We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II] and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass outflow rates. Thereby we observe a strong correlation of mass outflow rates with bolometric luminosity, and with the inferred mass accretion rates of the central objects, which continues through the Class 0 range the trend observed in Class II young stellar objects. Along this trend from large to small mass-flow rates, the different classes of young stellar objects lie in the sequence Class 0 -- Class I/flat-spectrum -- Class II, indicating that the trend is an evolutionary sequence in which mass outflow and accretion rates decrease together with increasing age, while maintaining rough proportionality. The survey results include two which are key tests of magnetocentrifugal outflow-acceleration mechanisms: the distribution of the outflow/accretion branching ratio b, and limits on the distribution of outflow speeds. Neither rule out any of the three leading outflow-acceleration, angular-momentum-ejection mechanisms, but they provide some evidence that disk winds and accretion-powered stellar winds (APSWs) operate in many protostars. An upper edge observed in the branching-ratio distribution is consistent with the upper bound of b = 0.6 found in models of APSWs, and a large fraction (0.31) of the sample have branching ratio sufficiently small that only disk winds, launched on scales as large as several AU, have been demonstrated to account for them.Comment: Version submitted to ApJ: 36 pages, 3 tables, 8 figure

Can improved canopy light transmission ameliorate loss of photosynthetic efficiency in the shade An investigation of natural variation in Sorghum bicolor

Previous studies have found that maximum quantum yield of CO2 assimilation (φCO2,max,app) declines in lower canopies of maize and miscanthus, a maladaptive response to self-shading. These observations were limited to single genotypes, leaving it unclear whether the maladaptive shade response is a general property of this C4 grass tribe, the Andropogoneae. We explored the generality of this maladaptation by testing the hypothesis that erect leaf forms (erectophiles), which allow more light into the lower canopy, suffer less of a decline in photosynthetic efficiency than drooping leaf (planophile) forms. On average, φCO2,max,app declined 27% in lower canopy leaves across 35 accessions, but the decline was over twice as great in planophiles than in erectophiles. The loss of photosynthetic efficiency involved a decoupling between electron transport and assimilation. This was not associated with increased bundle sheath leakage, based on 13C measurements. In both planophiles and erectophiles, shaded leaves had greater leaf absorptivity and lower activities of key C4 enzymes than sun leaves. The erectophile form is considered more productive because it allows a more effective distribution of light through the canopy to support photosynthesis. We show that in sorghum, it provides a second benefit, maintenance of higher φCO2,max,app to support efficient use of that light resource

Mass and ionic composition of atmospheric fine particles over Belgium and their relation with gaseous air pollutants

Original article can be found at: http://www.rsc.org/publishing/journals/EM/Index.asp Copyright Royal Society of Chemistry. DOI: 10.1039/b805157gMass, major ionic components (MICs) of PM2.5, and related gaseous pollutants (SO2, NOx, NH3, HNO2, and HNO3) were monitored over six locations of different anthropogenic influence (industrial, urban, suburban, and rural) in Belgium. SO42-, NO3- NH4+, and Na+ were the primary ions of PM2.5 with averages diurnal concentrations ranging from 0.4-4.5, 0.3-7.6, 0.9-4.9, and 0.4-1.2 g/m3, respectively. MICs formed 39% of PM2.5 on an average, but it could reach up to 80-98 %. The SO2, NO, NO2, HNO2, and HNO3 levels showed high seasonal and site-specific fluctuations. The NH3 levels were similar over all the sites (2-6 g/m3), indicating its relation to the evenly distributed animal husbandry activities. The sulfur and nitrogen oxidation ratios for PM2.5 point towards a low-to-moderate formation of secondary sulfate and nitrate aerosols over five cities/towns, but their fairly intensive formation at the rural Wingene. Cluster analysis revealed the association of three groups of compounds in PM2.5; (i) NH4NO3, KNO3; (ii) Na2SO4; and (iii) MgCl2, CaCl2, MgF2, CaF2, corresponding to anthropogenic, sea-salt, and mixed (sea-salt + anthropogenic) aerosols, respectively. The neutralization and cation-to-anion ratios indicate that MICs of PM2.5 appeared mostly as (NH4)2SO4 and NH4NO3 salts. Sea-salt input was maximal during winter reaching up to 12 % of PM2.5. The overall average Cl-loss for sea-salt particles of PM2.5 at the six sites varied between 69 and 96 % with an average of 87 %. Principal component analysis revealed vehicular emission, coal/wood burning and animal farming as the dominating sources for the ionic components of PM2.5.Peer reviewe

Mindfulness Training Supports Quality of Life and Advance Care Planning in Adults With Metastatic Cancer and Their Caregivers: Results of a Pilot Study

Background: Emotional distress often causes patients with cancer and their family caregivers (FCGs) to avoid end-of-life discussions and advance care planning (ACP), which may undermine quality of life (QoL). Most ACP interventions fail to address emotional barriers that impede timely ACP. Aim: We assessed feasibility, acceptability, and preliminary effects of a mindfulness-based intervention to facilitate ACP for adults with advanced-stage cancer and their FCGs. Design: A single-arm pilot was conducted to assess the impact of a 6-week group mindfulness intervention on ACP behaviors (patients only), QoL, family communication, avoidant coping, distress, and other outcomes from baseline (T1) to post-intervention (T2) and 1 month later (T3). Participants: Eligible patients had advanced-stage solid malignancies, limited ACP engagement, and an FCG willing to participate. Thirteen dyads (N = 26 participants) enrolled at an academic cancer center in the United States. Results: Of eligible patients, 59.1% enrolled. Attendance (70.8% across 6 sessions) and retention (84.6% for patients; 92.3% for FCGs) through T3 were acceptable. Over 90% of completers reported high intervention satisfaction. From T1 to T3, patient engagement more than doubled in each of 3 ACP behaviors assessed. Patients reported large significant decreases in distress at T2 and T3. Family caregivers reported large significant improvements in QoL and family communication at T2 and T3. Both patients and FCGs reported notable reductions in sleep disturbance and avoidant coping at T3. Conclusions: The mindfulness intervention was feasible and acceptable and supported improvements in ACP and associated outcomes for patients and FCGs. A randomized trial of mindfulness training for ACP is warranted

Abbreviated dignity therapy for adults with advanced-stage cancer and their family caregivers: Qualitative analysis of a pilot study

Objective Dignity therapy (DT) is designed to address psychological and existential challenges that terminally ill individuals face. DT guides patients in developing a written legacy project in which they record and share important memories and messages with those they will leave behind. DT has been demonstrated to ease existential concerns for adults with advanced-stage cancer; however, lack of institutional resources limits wide implementation of DT in clinical practice. This study explores qualitative outcomes of an abbreviated, less resource-intensive version of DT among participants with advanced-stage cancer and their legacy project recipients. Method Qualitative methods were used to analyze postintervention interviews with 11 participants and their legacy recipients as well as the created legacy projects. Direct content analysis was used to assess feedback from the interviews about benefits, barriers, and recommendations regarding abbreviated DT. The legacy projects were coded for expression of core values. Result Findings suggest that abbreviated DT effectively promotes (1) self-expression, (2) connection with loved ones, (3) sense of purpose, and (4) continuity of self. Participants observed that leading the development of their legacy projects promoted independent reflection, autonomy, and opportunities for family interaction when reviewing and discussing the projects. Consistent with traditional DT, participants expressed “family” as the most common core value in their legacy projects. Expression of “autonomy” was also a notable finding. Significance of results Abbreviated DT reduces resource barriers to conducting traditional DT while promoting similar benefits for participants and recipients, making it a promising adaptation warranting further research. The importance that patients place on family and autonomy should be honored as much as possible by those caring for adults with advanced-stage cancer

Feasibility and acceptability of an acceptance and commitment therapy intervention for caregivers of adults with Alzheimer’s disease and related dementias

Background: Caregivers of patients with Alzheimer's disease or a related dementia (ADRD) report high levels of distress, including symptoms of anxiety and depression, caregiving burden, and existential suffering; however, those with support and healthy coping strategies have less stress and burden. Acceptance and Commitment Therapy (ACT) aims to foster greater acceptance of internal events while promoting actions aligned with personal values to increase psychological flexibility in the face of challenges. The objective of this single-arm pilot, Telephone Acceptance and Commitment Therapy Intervention for Caregivers (TACTICs), was to evaluate the feasibility, acceptability, and preliminary effects of an ACT intervention on ADRD caregiver anxiety, depressive symptoms, burden, caregiver suffering, and psychological flexibility. Methods: ADRD caregivers ≥21 years of age with a Generalized Anxiety Disorder Scale (GAD-7) score ≥ 10 indicative of moderate or higher symptoms of anxiety were enrolled (N = 15). Participants received a telephone-based ACT intervention delivered by a non-licensed, bachelor's-prepared trained interventionist over 6 weekly 1-h sessions that included engaging experiential exercises and metaphors designed to increase psychological flexibility. The following outcome measures were administered at baseline (T1), immediately post-intervention (T2), 3 months post-intervention (T3), and 6 months post-intervention (T4): anxiety symptoms (GAD-7; primary outcome); secondary outcomes of depressive symptoms (Patient Health Questionnaire-9), burden (Zarit Burden Interview), suffering (The Experience of Suffering measure), psychological flexibility/experiential avoidance (Acceptance and Action Questionnaire-II), and coping skills (Brief COPE). Results: All 15 participants completed the study and 93.3% rated their overall satisfaction with their TACTICs experience as "completely satisfied." At T2, caregivers showed large reduction in anxiety symptoms (SRM 1.42, 95% CI [0.87, 1.97], p < 0.001) that were maintained at T3 and T4. At T4, psychological suffering (SRM 0.99, 95% CI [0.41, 1.56], p = 0.0027) and caregiver burden (SRM 0.79, 95% CI [0.21, 1.37], p = 0.0113) also decreased. Conclusions: Despite a small sample size, the 6-session manualized TACTICs program was effective in reducing anxiety, suggesting that non-clinically trained staff may be able to provide an effective therapeutic intervention by phone to maximize intervention scalability and reach

High-Resolution Spectroscopy on Trapped Molecular Ions in Rotating Electric Fields: A New Approach for Measuring the Electron Electric Dipole Moment

High-resolution molecular spectroscopy is a sensitive probe for violations of fundamental symmetries. Symmetry violation searches often require, or are enhanced by, the application of an electric field to the system under investigation. This typically precludes the study of molecular ions due to their inherent acceleration under these conditions. Circumventing this problem would be of great benefit to the high-resolution molecular spectroscopy community since ions allow for simple trapping and long interrogation times, two desirable qualities for precision measurements. Our proposed solution is to apply an electric field that rotates at radio frequencies. We discuss considerations for experimental design as well as challenges in performing precision spectroscopic measurements in rapidly time-varying electric fields. Ongoing molecular spectroscopy work that could benefit from our approach is summarized. In particular, we detail how spectroscopy on a trapped diatomic molecular ion with a ground or metastable &sup3;&Delta;₁ level could prove to be a sensitive probe for a permanent electron electric dipole moment (eEDM).</p