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Active transportation to school (ATS) is a component of a whole school approach to health promotion among youth.Individual- and school-level predictors of ATS were examined using data from parent surveys (N = 11,100) of students in grades 3-8 attending 112 schools in Arizona (United States) administering Safe Routes to School (SRTS) programs between 2007 and 2018. Multilevel logistic models were estimated to predict the likelihood of students using active (walking or biking) versus inactive travel (riding bus or car) to and from school, and across distance and school-level income categories.Student grade, parent education, asking permission to use ATS, perceived health and school support for ATS, distance, and school income were predictive of ATS. The impact of demographic factors persisted across distances of ½ mile or less and at low- and medium-income schools but diminished as distance and income increased. Asking permission and perceived school support persisted across levels of distance and income, while perceiving ATS as healthy was significant only for distances under 1 mile.SRTS programs should continue promoting health benefits and school support for ATS. SRTS may be particularly effective at low- and medium-income schools and among families living within ½ mile distances.

Background About 1 in every 150 pregnancies end in stillbirth. Consequences include symptoms of post traumatic stress disorder (PTSD), depression, and anxiety. Yoga has been used to treat PTSD in other populations and may improve health outcomes for stillbirth mothers. The purpose of this study was to determine: (a) feasibility of a 12-week home-based, online yoga intervention with varying doses; (b) acceptability of a “stretch and tone” control group; and (c) preliminary efficacy of the intervention on reducing symptoms of PTSD, anxiety, depression, perinatal grief, self-compassion, emotional regulation, mindfulness, sleep quality, and subjective health. Methods Participants (N = 90) were recruited nationally and randomized into one of three groups for yoga or exercise (low dose (LD), 60 min per week; moderate dose (MD), 150 min per week; and stretch-and-tone control group (STC)). Baseline and post-intervention surveys measured main outcomes (listed above). Frequency analyses were used to determine feasibility. Repeated measures ANCOVA were used to determine preliminary efficacy. Multiple regression analyses were used to determine a dose-response relationship between minutes of yoga and each outcome variable. Results Over half of participants completed the intervention (n = 48/90). Benchmarks (≥70% reported > 75% satisfaction) were met in each group for satisfaction and enjoyment. Participants meeting benchmarks (completing > 90% of prescribed minutes 9/12 weeks) for LD and MD groups were 44% (n = 8/18) and 6% (n = 1/16), respectively. LD and MD groups averaged 44.0 and 77.3 min per week of yoga, respectively. The MD group reported that 150 prescribed minutes per week of yoga was too much. There were significant decreases in PTSD and depression, and improvements in self-rated health at post-intervention for both intervention groups. There was a significant difference in depression scores (p = .036) and grief intensity (p = .009) between the MD and STC groups. PTSD showed non-significant decreases of 43% and 56% at post-intervention in LD and MD groups, respectively (22% decrease in control). Conclusions This was the first study to determine the feasibility and preliminary efficacy of an online yoga intervention for women after stillbirth. Future research warrants a randomized controlled trial. Trial registration ClinicalTrials.gov. NCT02925481. Registered 10–04-16.

OBJECTIVE/ BACKGROUND: Food Insecurity (FI) can be a profound source of stress, which may increase the risk for sleep disturbance. This is the first study to examine the association between FI and objectively and subjectively measured sleep. PARTICIPANTS: The sample included 785 adults living in two low-income neighborhoods (mean age=56; 95% African American). OBJECTIVE: Our study is the first to examine the association between FI and multiple dimensions of sleep, assessed objectively and subjectively. METHODS: FI was measured using a 10-item survey that assesses conditions and behaviors that characterize households when they lack financial resources to meet basic food needs. Sleep duration, efficiency, wakefulness after sleep onset (WASO), and variability in sleep duration were measured via actigraphy. Sleep quality was assessed via sleep diary. Sleep outcomes were analyzed as a function of FI, adjusting for covariates. Psychological distress was tested as a potential mediator. RESULTS: Greater FI was associated with shorter actigraphy-assessed sleep duration (B=−2.44; SE=1.24; i.e., 24 minutes shorter for the most as compared to least insecure group), poorer sleep efficiency (B=−.27; SE=.13); p’s 9 hours; OR =1.19; CI: 1.01–1.39), compared to the recommended sleep duration of 7–9 hours. Psychological distress partially mediated the association between FI and subjective sleep quality. CONCLUSIONS: FI is an independent correlate of sleep disturbance. Findings demonstrate the importance of considering novel social determinants underlying sleep health disparities.

In this paper, we present results of Fourier-transformed photoluminescence measurements of quaternary GaInAsSb quantum wells with quinary AlGaInAsSb barriers grown on GaSb substrate, designed for spectral range of mid-infrared. Here, we show an emission shift towards longer wavelength as a result of incorporation of indium into the quantum wells reaching up to 3 μm at room temperature (RT). Additionally, we have observed an additional low-energy photoluminescence signal with maximum wavelength of 3.5 μm at RT, which we have attributed as states localised on the layer interfaces. The activation energy of carriers trapped in those states is estimated to be 35 meV.

Youth aging out of the foster care system have well-documented challenges when transitioning to adulthood. Multiple transition services provide support in the transition process; however, limited research is available regarding youth’s perceptions of programming. In this pilot study, sixteen youth between ages 18 and 20 participated in semi-structured interviews, support mapping, and resiliency measurements to gather the experiences of the transition from foster care. Comparisons between those who chose initial transition supports and those who did not receive or delayed receiving transition supports were initially explored. Common themes emerged in participants’ needs and perceived resiliency regardless of transition support services. All youth reported relationship, trust, and concern for well-being as highly important characteristics in transition team members. A need for earlier transition programming, decision-making opportunities, and life skills courses were important themes in transition programming needs. Implications for policy, research, and practice are presented based upon findings.

The precise determination of carrier concentration in doped semiconductor materials and nanostructures is of high importance. Many parameters of an operational device are dependent on the proper carrier concentration or its distribution in both the active area as well as in the passive parts as the waveguide claddings. Determining those in a nondestructive manner is, on the one hand, demanded for the fabrication process efficiency, but on the other, challenging experimentally, especially for complex multilayer systems. Here, we present the results of carrier concentration determination in In0.53Ga0.47As layers, designed to be a material forming quantum cascade laser active areas, using a direct and contactless method utilizing the Berreman effect, and employing Fourier-transform infrared (FTIR) spectroscopy. The results allowed us to precisely determine the free carrier concentration versus changes in the nominal doping level and provide feedback regarding the technological process by indicating the temperature adjustment of the dopant source.

Background: Myeloproliferative neoplasm (MPN) patients often report high symptom burden that persists despite the best available pharmacologic therapy. Meditation has gained popularity in recent decades as a way to manage cancer patient symptoms. Objective: The aim of this study was to examine the feasibility of 2 different consumer-based meditation smartphone apps in MPN patients and to examine the limited efficacy of smartphone-based meditation on symptoms compared with an educational control group. Methods: Patients (n=128) were recruited nationally through organizational partners and social media. Eligible and consented patients were enrolled into 1 of 4 groups, 2 of which received varying orders of 2 consumer-based apps (10% Happier and Calm) and 2 that received one of the apps alone for the second 4 weeks of the 8-week intervention after an educational control condition. Participants were asked to perform 10 min of meditation per day irrespective of the app and the order in which they received the apps. Feasibility outcomes were measured at weeks 5 and 9 with a Web-based survey. Feasibility outcomes were acceptability, demand, and limited efficacy for depression, anxiety, pain intensity, sleep disturbance, sexual function, quality of life, global health, and total symptom burden. Results: A total of 128 patients were enrolled across all 4 groups, with 73.4% (94/128) patients completing the intervention. Of the participants who completed the 10% Happier app, 61% (46/76) enjoyed it, 66% (50/76) were satisfied with the content, and 77% (59/76) would recommend to others. Of those who completed the Calm app, 83% (56/68) enjoyed it, 84% (57/68) were satisfied with the content, and 97% (66/68) would recommend to others. Of those who completed the educational control, 91% (56/61) read it, 87% (53/61) enjoyed it, and 71% (43/61) learned something. Participants who completed the 10% Happier app averaged 31 (SD 33) min/week; patients completing the Calm app averaged 71 (SD 74) min/week. 10% Happier app participants saw small effects on anxiety (P

An infrequently studied question is how diverse combinations of built environment (BE) features relate to physical activity (PA) for older adults. We derived patterns of Geographical Information Systems- (GIS) measured BE features and explored how they accounted for differences in objective and self-reported PA, sedentary time, and BMI in a sample of older adults. Senior Neighborhood Quality of Life Study participants (N=714, aged 66–97 years, 52.1% women, 29.7% racial/ethnic minority) were sampled in 2005–2008 from the Seattle-King County, WA and Baltimore, MD-Washington, DC regions. Participants’ home addresses were geocoded, and net residential density, land use mix, retail floor area ratio, intersection density, public transit density, and public park and private recreation facility density measures for 1-km network buffers were derived. Latent profile analyses (LPAs) were estimated from these GIS-based measures. In multilevel regression models, profiles were compared on accelerometer-measured moderate-to-vigorous PA (MVPA) and sedentary time and self-reported PA, adjusting for covariates and clustering. Analyses were conducted in 2014–2015. LPAs yielded three profiles: low walkability/transit/recreation (L-L-L); mean walkability/transit/recreation (M-M-M); and high walkability/transit/recreation (H-H-H). Three PA outcomes were more favorable in the HHH than the LLL profile group (difference of 7.2 minutes/day for MVPA, 97.8 minutes/week for walking for errands, and 79.2 minutes/week for walking for exercise; all ps < 0.02). The most and least activity-supportive BE profiles showed greater differences in older adults’ PA than did groupings based solely on a 4-component walkability index, suggesting that diverse BE features are important for healthy aging.

Interatomic Coulombic Decay (ICD) is a relaxation phenomenon, which takes place in weakly bound atomic and molecular systems, typically within a few to hundreds of femtoseconds depending on the system and the particular decay mechanism. The creation of ICD-active states requires the production of highly excited systems, usually populated by innershell ionization or excitation. To this end, XUV and X-ray radiation from synchrotrons was conventionally applied for the majority of experiments due to the desired state-selective ionization of certain sub-shells. The advent of Free-Electron Lasers (FELs) has enabled an entirely new class of experiments, which finally allow to trace ICD directly in the time domain due to the femtosecond pulse duration. Within this paper, the first time-resolved ICD measurement using an XUV-pump–XUV-probe scheme will be discussed in detail. The experiment was performed on neon dimers and ICD was triggered by removing a 2s electron from one of the neon atoms using a 58 eV pulse from the FEL in Hamburg (FLASH). The onset of ICD was probed with a delayed copy of the trigger pulse that further ionized one of the two Ne+ ions emerging after ICD. Thus, the delay-dependent yield of coincident Ne+ + Ne2+ ion pairs contains the lifetime of the 2s-innershell vacancy decaying via ICD. The result of 150 fs ± 50 fs is in good agreement with theory but only for those calculations that explicitly take nuclear motion into account.

Characterizing neighborhood environments in relation to physical activity is complex. Latent profiles of parents’ perceptions of neighborhood characteristics were examined in relation to accelerometer-measured moderate-to-vigorous physical activity (MVPA) among 678 children (ages 6-12) in two US regions. Neighborhood environment profiles derived from walkability, transit access, aesthetics, crime and traffic safety, pedestrian infrastructure, and recreation/park access were created for each region. The San Diego County profile lowest on walkability and recreation/park access was associated with an average of 13 fewer minutes/day of children’s out-of-school MVPA compared to profiles higher on walkability and recreation/park access. Seattle/King County profiles did not differ on children’s MVPA. Neighborhood environment profiles were associated with children’s MVPA in one region, but results were inconsistent across regions.

Background To test inter-rater reliability of the online Microscale Audit of Pedestrian Streetscapes (MAPS) tool between raters with varying familiarities of Phoenix, Arizona. Methods The online MAPS tool, based on the MAPS in-field audit tool and scoring system, was used for audits. Sixty route pairs, 141 segment pairs, and 92 crossing pairs in Phoenix were included. Each route, segment or crossing was audited by two independent raters: one rater in Phoenix and the other in San Diego, California, respectively. Item, subscale scores, and total scores reliability analyses were computed using Kappa or intra-class correlation coefficient (ICC). Results The route overall score had substantial reliability (ICC: 0.832). Of the route subscale and overall scores, sixteen out of twenty had moderate to substantial reliability (ICC: 0.616–0.906), and the four subscales had fair reliability (ICC: 0.409–0.563). Sixteen out of twenty scores in segment and crossing sections demonstrated fair to substantial reliability (ICC: 0.448–0.897), and the remaining four had slight reliability (ICC: 0.348–0.364). Conclusions Most of the online MAPS items, subscales, and overall scores demonstrated fair to substantial reliability between raters with varied familiarities of the Phoenix area. Results support use of online MAPS to measure microscale elements of the built environment by raters unfamiliar with a region.

This project has received funding from the European Commission's Horizon 2020 Research and Innovation Programme iCspec under grant agreement No. 636930 and has also been supported by the National Science Centre of Poland within Grant No. 2014/15/B/ST7/04663. Two designs of active region for an interband cascade laser, based on double or triple GaInSb/InAs type II quantum wells (QWs), were compared with respect to passive mode-locked operation in the mid-infrared range around 4 µm. The layer structure and electron and hole wavefunctions under external electric field were engineered to allow controlling the optical transition oscillator strength and the resulting lifetimes. As a result, the investigated structures can mimic absorber-like and gain-like sections of a mode-locked device when properly polarized with opposite bias. A significantly larger oscillator strength tuning range for triple QWs was experimentally verified by Fourier-transform photoreflectance. Publisher PDF

Relationships between food and physical activity (PA) environments and children's related behaviors are complex. Latent class analyses derived patterns from proximity to healthy and unhealthy food outlets, PA facilities and parks, and counts of residential dwellings and intersections. Regression analyses examined whether derived classes were related to food consumption, PA, and overweight among 404 low-income children. Compared to children living in Low PA-Low Food environments, children in High Intersection&Parks-Moderate Density&Food, and High Density-Low Parks-High Food environments, had significantly greater sugar-sweetened beverage consumption (ps

In this communication, we focus on the optical properties of InAsSbP/InAsSb/InAsSbP single quantum well structures grown on InAs substrates using the metal-organic vapor phase epitaxy (MOVPE) technique. The obtained Fourier transformed photoluminescence spectra allowed us to perform an advanced analysis of the temperature evolution of the measured spectra, which revealed radiative recombination at room temperature in the mid-infrared spectral range (~3.5 μm) associated with localized states in the quantum well. These results suggest that improvements in the quality of the InAsSbP/InAsSb heterointerfaces could open the way to new types of heterostructures based on nanoscale systems for the fabrication of cheap mid-infrared lasers and light-emitting diodes, which are demanded by the optical gas sensing market.

Sleep and sedentary and active behaviors are linked to cardiovascular disease risk biomarkers, and across a 24-hour day, increasing time in 1 behavior requires decreasing time in another. We explored associations of reallocating time to sleep, sedentary behavior, or active behaviors with biomarkers. Data (n = 2,185 full sample; n = 923 fasting subanalyses) from the cross-sectional 2005-2006 US National Health and Nutrition Examination Survey were analyzed. The amounts of time spent in sedentary behavior, light-intensity activity, and moderate-to-vigorous physical activity (MVPA) were derived from ActiGraph accelerometry (ActiGraph LLC, Pensacola, Florida), and respondents reported their sleep duration. Isotemporal substitution modeling indicated that, independent of potential confounders and time spent in other activities, beneficial associations (P < 0.05) with cardiovascular disease risk biomarkers were associated with the reallocation of 30 minutes/day of sedentary time with equal time of either sleep (2.2% lower insulin and 2.0% lower homeostasis model assessment of β-cell function), light-intensity activity (1.9% lower triglycerides, 2.4% lower insulin, and 2.2% lower homeostasis model assessment of β-cell function), or MVPA (2.4% smaller waist circumference, 4.4% higher high-density lipoprotein cholesterol, 8.5% lower triglycerides, 1.7% lower glucose, 10.7% lower insulin, and 9.7% higher homeostasis model assessment of insulin sensitivity. These findings provide evidence that MVPA may be the most potent health-enhancing, time-dependent behavior, with additional benefit conferred from light-intensity activities and sleep duration when reallocated from sedentary time.

BackgroundAn online version of the Microscale Audit of Pedestrian Streetscapes (Abbreviated) tool was adapted to virtually audit built environment features supportive of physical activity. The current study assessed inter-rater reliability of MAPS Online between in-person raters and online raters unfamiliar with the regions.MethodsIn-person and online audits were conducted for a total of 120 quarter-mile routes (60 per site) in Phoenix, AZ and San Diego, CA. Routes in each city included 40 residential origins stratified by walkability and SES, and 20 commercial centers. In-person audits were conducted by raters residing in their region. Online audits were conducted by raters in the alternate location using Google Maps (Aerial and Street View) images. The MAPS Abbreviated Online tool consisted of four sections: overall route, street segments, crossings and cul-de-sacs. Items within each section were grouped into subscales, and inter-rater reliability (ICCs) was assessed for subscales at multiple levels of aggregation.ResultsOnline and in-person audits showed excellent agreement for overall positive microscale (ICC=0.86, 95% CI [0.80, 0.90]) and grand scores (ICC=0.93, 95% CI [0.89, 0.95]). Substantial to near-perfect agreement was found for 21 of 30 (70%) subscales, valence, and subsection scores, with ICCs ranging from 0.62, 95% CI [0.50, 0.72] to 0.95, 95% CI [0.93, 0.97]. Lowest agreement was found for the aesthetics and social characteristics scores, with ICCs ranging from 0.07, 95% CI [-0.12, 0.24] to 0.27, 95% CI [0.10, 0.43].ConclusionsResults support use of the MAPS Abbreviated Online tool to reliably assess microscale neighborhood features that support physical activity and may be used by raters residing in different geographic regions and unfamiliar with the audit areas.

We would like to acknowledge the National Science Centre of Poland for support within Grant No. 2014/15/B/ST7/04663. Optical properties of AlSb/InAs/GaInSb/InAs/AlSb quantum wells (QWs) grown on an InAs substrate were investigated from the point of view of room temperature emission in the mid- and long-wavelength infrared ranges. By means of two independent techniques of optical spectroscopy, photoreflectance and temperature-dependent photoluminescence, it was proven that the main process limiting the performance of such InAs substrate-based type II structures is related to the escape of carriers from the hole ground state of the QW. Two nonradiative recombination channels were identified. The main process was attributed to holes tunneling to the valence band of the GaAsSb spacing layer and the second one with trapping of holes by native defects located in the same layer. Publisher PDF

Land use mix reflects the availability of diverse destinations providing opportunities for active transportation. Online mapping platforms (e.g. Google Maps) show promise for measuring neighborhood features due to their ease of use and accessibility. The purpose of this study was to evaluate the validity and reliability of an online version of the Microscale Audit of Pedestrian Streetscapes (MAPS) tool by comparing Google׳s Aerial View (AV), Street View (SV), and a composite of the two views (Composite) to in-person field audits. Raters evaluated residential routes and commercial clusters ( n =120) using the online MAPS tool in low and high walkability and socioeconomic status (SES) neighborhoods of two U.S. regions. Thirty land uses were evaluated for each route and cluster. Concurrent validity between field and online audits was examined using percent agreement and weighted kappa statistics ( κ ) for individual items and intra-class correlation coefficients (ICCs) for item subscales. Reliability was examined using ICCs. Most field-to-online land use item comparisons showed moderate to perfect agreement ( κ =0.41–0.88). SV (10 out of 19 comparisons) outperformed AV (7 out of 19) and Composite (9 out of 19) compared to field audits. Subscale comparisons were fair to almost perfect (ICC 0.27-0.89). AV (7 out of 10 subscales) outperformed SV compared to field audits. Reliability between AV and SV was substantial to perfect (ICC 0.61-1.00) for most items (15 out of 21 eligible items) and substantial to almost perfect (ICC 0.61-0.96) for 9 of the 10 subscales. Online approaches did not differ after stratifying routes by SES. Audits using online MAPS were an acceptable alternative to evaluating land uses in the field. The Street View method is recommended based on better performance with individual land uses and equal performance in high and low socioeconomic status neighborhoods.

Background The purpose of this study is to determine the feasibility of three widely used wearable sensors in research settings for 24 h monitoring of sleep, sedentary, and active behaviors in middle-aged women. Methods Participants were 21 inactive, overweight (M Body Mass Index (BMI) = 29.27 ± 7.43) women, 30 to 64 years (M = 45.31 ± 9.67). Women were instructed to wear each sensor on the non-dominant hip (ActiGraph GT3X+), wrist (GENEActiv), or upper arm (BodyMedia SenseWear Mini) for 24 h/day and record daily wake and bed times for one week over the course of three consecutive weeks. Women received feedback about their daily physical activity and sleep behaviors. Feasibility (i.e., acceptability and demand) was measured using surveys, interviews, and wear time. Results Women felt the GENEActiv (94.7 %) and SenseWear Mini (90.0 %) were easier to wear and preferred the placement (68.4, 80 % respectively) as compared to the ActiGraph (42.9, 47.6 % respectively). Mean wear time on valid days was similar across sensors (ActiGraph: M = 918.8 ± 115.0 min; GENEActiv: M = 949.3 ± 86.6; SenseWear: M = 928.0 ± 101.8) and well above other studies using wake time only protocols. Informational feedback was the biggest motivator, while appearance, comfort, and inconvenience were the biggest barriers to wearing sensors. Wear time was valid on 93.9 % (ActiGraph), 100 % (GENEActiv), and 95.2 % (SenseWear) of eligible days. 61.9, 95.2, and 71.4 % of participants had seven valid days of data for the ActiGraph, GENEActiv, and SenseWear, respectively. Conclusion Twenty-four hour monitoring over seven consecutive days is a feasible approach in middle-aged women. Researchers should consider participant acceptability and demand, in addition to validity and reliability, when choosing a wearable sensor. More research is needed across populations and study designs.

Introduction: Diverse combinations of built environment (BE) features for physical activity (PA) are understudied. This study explored whether patterns of GIS-derived BE features explained objective and self-reported PA, sedentary behavior, and BMI. Methods: Neighborhood Quality of Life Study participants (N=2,199, aged 20–65 years, 48.2% female, 26% ethnic minority) were sampled in 2001–2005 from Seattle / King County WA and Baltimore MD / Washington DC regions. Their addresses were geocoded to compute net residential density, land use mix, retail floor area ratio, intersection density, public transit, and public park and private recreation facility densities using a 1-km network buffer. Latent profile analyses (LPAs) were estimated from these variables. Multilevel regression models compared profiles on accelerometer-measured moderate to vigorous PA (MVPA) and self-reported PA, adjusting for covariates and clustering. Analyses were conducted in 2013–2014. Results: Seattle region LPAs yielded four profiles, including low walkability/transit/recreation (L-L-L); mean walkability/transit/recreation (M-M-M); moderately high walkability/transit/recreation (MH-MH-MH); and high walkability/transit/recreation (H-HH). All measures were higher in the HHH than the LLL profile (difference of 17.1 minutes/day for MVPA, 146.5 minutes/week for walking for transportation, 58.2 minutes/week for leisure-time PA, and 2.2 BMI points; all p < 0.05). Baltimore region LPAs yielded four profiles, including L-L-L; M-M-M; high land use mix, transit, and recreation (HLU-HT-HRA); and high intersection density, high retail floor area ratio (HID-HRFAR). HLU-HT-HRA and L-L-L differed by 12.3 MVPA minutes/day; HID-HRFAR and L-L-L differed by 157.4 minutes/week for walking for transportation (all p < 0.05). Conclusions: Patterns of environmental features explain greater differences in adults’ PA than the four-component walkability index.

One of the most challenging tasks for extreme ultraviolet, soft and hard x ray free electron laser photon diagnostics is the precise determination of the photon pulse duration, which is typically in the sub 100 fs range. Nine different methods, able to determine such ultrashort photon pulse durations, were compared experimentally at FLASH, the self amplified spontaneous emission free electron laser at DESY in Hamburg, in order to identify advantages and disadvantages of different methods. Radiation pulses at a wavelength of 13.5 and 24.0 nm together with the corresponding electron bunch duration were measured by indirect methods like analyzing spectral correlations, statistical fluctuations, and energy modulations of the electron bunch and also by direct methods like autocorrelation techniques, terahertz streaking, or reflectivity changes of solid state samples. In this paper, we present a comprehensive overview of the various techniques and a comparison of the individual experimental results. The information gained is of utmost importance for the future development of reliable pulse duration monitors indispensable for successful experiments with ultrashort extreme ultraviolet pulses

The ionization and fragmentation dynamics of iodine molecules (I2) are traced using very intense (∼1014 W cm−2) ultra-short (∼60 fs) light pulses with 87 eV photons of the Free-electron LASer at Hamburg (FLASH) in combination with a synchronized femtosecond optical laser. Within a pump–probe scheme the IR pulse initiates a molecular fragmentation and then, after an adjustable time delay, the system is exposed to an intense FEL pulse. This way we follow the creation of highly-charged molecular fragments as a function of time, and probe the dynamics of multi-photon absorption during the transition from a molecule to individual atoms.

INTRODUCTION A growing body of evidence demonstrates the health benefits of muscular strength training. Physical activity recommendations encourage all adults to participate regularly in muscle strengthening activities. The purpose of this study was to examine the prevalence of meeting the US Department of Health and Human Services (DHHS) muscular strengthening recommendations by middle-aged and older adults and the sociodemographic characteristics associated with meeting these recommendations, using data from the 2011 Behavioral Risk Factor Surveillance System (BRFSS). METHODS Data from the 2011 BRFSS were used to examine the prevalence of meeting the DHHS muscle strengthening recommendations by adults older than 45. Simple and multiple regression analyses were used to examine the sociodemographic characteristics associated with meeting the recommendations. RESULTS Of respondents to the muscle strengthening question (N = 333,507), 79,029 (23.7%) reported meeting the muscle strengthening recommendations. Respondents who were female (odds ratio [OR] = 0.80; 95% confidence interval [CI] 0.78-0.83), widowed (OR = 0.69; 95% CI, 0.66-0.72), 85 or older (OR = 0.63; 95% CI, 0.58-0.68), Hispanic (OR = 0.73; 95% CI, 0.67-0.78), with a body mass index of 30.0 kg/m(2) or higher (OR = 0.47; 95% CI, 0.45-0.49), and with less than a high school education (OR = 0.32, 95% CI, 0.30-0.35) were less likely to meet the recommendations than their counterparts. CONCLUSION Sociodemographic characteristics such as sex, age, education, and race/ethnicity are significantly associated with meeting the muscle strengthening recommendations, suggesting a need to create tailored interventions and messages to promote participation in strength training.

The charge rearrangement in dissociating ${\mathrm{I}}_{2}^{n+}$ molecules is measured as a function of the internuclear distance $R$ using extreme ultraviolet pulses delivered by the free-electron laser in Hamburg. Within an extreme ultraviolet pump-probe scheme, the first pulse initiates dissociation by multiply ionizing ${\mathrm{I}}_{2}$, and the delayed probe pulse further ionizes one of the two fragments at a given time, thus triggering charge rearrangement at a well-defined $R$. The electron transfer between the fragments is monitored by analyzing the delay-dependent ion kinetic energies and charge states. The experimental results are in very good agreement with predictions of the classical over-the-barrier model demonstrating its validity in a thus far unexplored quasimolecular regime relevant for free-electron laser, plasma, and chemistry applications.

The dynamics of multi-photon induced fragmentation of N2 has been investigated in XUV-pump/XUV-probe experiments at the Free-Electron Laser in Hamburg (FLASH) by recording the ion kinetic energy release(KER) and angular distributions for various dissociation- and Coulomb-explosion channels as a function of the pump-probe delay-time.

Few-photon induced ultrafast dynamics in acetylene (C 2 H 2 ) leading to several dissociation channels—deprotonation (H + + C 2 H + and H + + C 2 H 2 + ), symmetric break-up (CH + + CH + ) and isomerization (C + + CH 2 + )—were investigated employing the (XUV; extreme ultra-violet)-pump–(XUV; extreme ultra-violet)-probe scheme at the free-electron laser in Hamburg, combined with multi-hit coincidence detection. The kinetic energy releases and fragment-ion momentum distributions for various decay channels are presented. The C + + CH 2 + and H + + C 2 H 2 + channels reveal clear signatures of ultrafast molecular mechanisms, demonstrating potential applications of our pump-probe technique to complex systems in order to study a large variety of ultrafast phenomena in the XUV regime.

The lifetime of interatomic Coulombic decay (ICD) [L. S. Cederbaum et al., Phys. Rev. Lett. 79, 4778 (1997)] in Ne_2 is determined via an extreme ultraviolet pump-probe experiment at the Free-Electron Laser in Hamburg. The pump pulse creates a 2s inner-shell vacancy in one of the two Ne atoms, whereupon the ionized dimer undergoes ICD resulting in a repulsive Ne^{+}(2p^{-1}) - Ne^{+}(2p^{-1}) state, which is probed with a second pulse, removing a further electron. The yield of coincident Ne^{+} - Ne^{2+} pairs is recorded as a function of the pump-probe delay, allowing us to deduce the ICD lifetime of the Ne_{2}^{+}(2s^{-1}) state to be (150 +/- 50) fs in agreement with quantum calculations., 5 pages, 3 figures, accepted by PRL on July 11th, 2013

We show how light field s that vary statistically in time (e.g. at FELs) enable higher temporal resolution than expected from their average pulse duration. An experimental example in deuterium molecules confirmed this general effect.

We carried out time-of-flight mass spectrometry for neon clusters that were exposed to intense free electron laser pulses with the wavelength of 62 nm, which induce optical transition from the ground state (2s 2 2p 6 ) to an excited state (2s 2 2p 5 nl ) in the Ne atoms. In contrast to Ne + ions produced by two-photon absorption from isolated Ne atoms, the Ne + ion yield from Ne clusters shows a linear dependence on the laser intensity (I). We discuss the ionization mechanisms which give the linear behaviour with respect to I and expected features in the electron emission spectrum. (Some figures may appear in colour only in the online journal)

Acta crystallographica / D 69(5), 838 - 842 (2013). doi:10.1107/S0907444913002448, X-ray free-electron lasers (FELs) enable crystallographic data collection using extremely bright femtosecond pulses from microscopic crystals beyond the limitations of conventional radiation damage. This diffraction-before-destruction approach requires a new crystal for each FEL shot and, since the crystals cannot be rotated during the X-ray pulse, data collection requires averaging over many different crystals and a Monte Carlo integration of the diffraction intensities, making the accurate determination of structure factors challenging. To investigate whether sufficient accuracy can be attained for the measurement of anomalous signal, a large data set was collected from lysozyme microcrystals at the newly established `multi-purpose spectroscopy/imaging instrument' of the SPring-8 Ångstrom Compact Free-Electron Laser (SACLA) at RIKEN Harima. Anomalous difference density maps calculated from these data demonstrate that serial femtosecond crystallography using a free-electron laser is sufficiently accurate to measure even the very weak anomalous signal of naturally occurring S atoms in a protein at a photon energy of 7.3 keV., Published by Wiley-Blackwell, Oxford

We traced the femtosecond nuclear-wave-packet dynamics in ionic states of oxygen and nitrogen diatomic molecules employing 38-eV XUV-pump--XUV-probe experiments at the free-electron laser in Hamburg (FLASH). The nuclear dynamics is monitored via the detection of coincident ionic fragments using a reaction microscope and a split-mirror setup to generate the pump and probe pulses. By comparing measured kinetic-energy-release spectra with classical and quantum-mechanical simulations, we identified electronic states of the molecular ions that are populated by ionization of the neutral molecule. For specific fragment charge states, this comparison allows us to assess the relevance of specific dissociation paths.

Using a split focusing mirror, XUV pump–probe measurements have been performed at the free-electron laser at Hamburg (FLASH). The obtained non-linear autocorrelation signals can be used to characterize the ultra-short photon pulses generated by the machine at different control parameters.

A setup for XUV-XUV pump-probe experiments with atoms and molecules using femtosecond FEL radiation will be presented along with first time-resolved results on the XUV induced fragmentation dynamics of small molecules.

We present EUV autocorrelation measurements of free-electron laser (FEL) pulses at 28 eV photon energy exploiting multiple ionization of argon as a non-linear process. In this way, the average pulse duration is measured while in parallel insight is gained into the temporal structure of the pulses. We compare the obtained results with FEL pulse simulations using our partial-coherence method (T. Pfeifer et al., Opt. Lett. 35:3441 (2010)).

Using a split-mirror stage combined with a reaction microscope, nonlinear autocorrelation traces of XUV pulses from the Free-electron LASer at Hamburg were recorded for ${\mathrm{N}}_{2}$ multiphoton-induced fragmentation into noncoincident ${\mathrm{N}}^{2+}$ and coincident ${\mathrm{N}}^{2+}+{\mathrm{N}}^{2+}$ channels. We find a pulse duration of $40\ifmmode\pm\else\textpm\fi{}10 \mathrm{fs}$ along with a sharp spike pointing to a coherence time of $4\ifmmode\pm\else\textpm\fi{}1 \mathrm{fs}$, almost twice as short as in previous observations. Both are well reproduced by a simulation based on the partial-coherence model that includes the molecular dynamics leading to an $~12\ensuremath{-}\mathrm{fs}$ substructure in the trace.

International audience; In this contribution we briefly review a series of recent pioneering experiments on fewphoton-induced multiple fragmentation of atoms and molecules performed at the Free electron LASer at Hamburg (FLASH) using a " Reaction Microscope ", i.e., a coincident momentum imaging technique. For atoms we consider the most basic non-linear process, namely direct or sequential two-photon double ionization (TPDI). In particular benchmark data for theory are presented such as recoil-ion momentum distributions for direct TPDI of He and Ne, and fully differential data for sequential TPDI of Ne. For molecules we show how one can identify contributions from different reaction channels by inspecting the measured kinetic energy and angular distributions of ionic fragments, and even infer the time-delay between the two photon absorption events in TPDI by detailed comparison with theory. Finally, we describe a novel split mirror arrangement for EUV-pump – EUV-probe experiments, and present the very first time-resolved data on the dynamics of N 2 molecules irradiated by the FLASH light.

Using a novel split-mirror set-up attached to a Reaction Microscope at the Free electron LASer in Hamburg (FLASH) we demonstrate an XUV-pump - XUV-probe experiment by tracing the ultra-fast nuclear wave-packet motion in the D2 +.

The interaction of clusters with intense EUV-FEL pulses was investigated using the SPring-8 Compact SASE Source (SCSS) test facility in Japan. Neon clusters of mean sizes = 1000 and 4000 were irradiated by intense FEL pulses at 52 nm and emitted ions were detected by a momentum imaging spectrometer. The production of energetic doubly charged ions was not found for Ne 1000, but it was observed for Ne 4000 clusters, which suggests that an inhomogeneous charge distribution is generated for the larger clusters.

Physical review letters 105, 263002 (2010). doi:10.1103/PhysRevLett.105.263002, Published by APS, College Park, Md.

Using a reaction microscope, three-dimensional (3D) electron (and ion) momentum ($\mathbf{P}$) spectra have been recorded for carrier-envelope-phase (CEP) stabilized few-cycle ($\ensuremath{\sim}5\text{ }\text{ }\mathrm{fs}$), intense ($\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{14}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$) laser pulses (740 nm) impinging on He. Preferential emission of low-energy electrons (${E}_{e}l15\text{ }\text{ }\mathrm{eV}$) to either hemisphere is observed as a function of the CEP. Clear interference patterns emerge in $\mathbf{P}$ space at CEPs with maximum asymmetry, interpreted as attosecond interferences of rescattered and directly emitted electron wave packets by means of a simple model.

Journal of physics / B 42, 141002 (2009). doi:10.1088/0953-4075/42/14/141002, Published by IOP Publ., Bristol

Few-photon multiple ionization of N2 was studied differentially in a reaction microscope using 44 eV, approximately 25 fs, intense ( approximately 10(13) W/cm(2)) photon pulses from FLASH. Sequential ionization is observed to dominate. For various intermediate charge states N(2)(n+0 we find a considerable excess of photons absorbed compared to the minimum number that would energetically be required. Photoionization of aligned N(2)(n+) ions, produced by photon absorption in sequential steps, is explored and few-photon absorption pathways are traced by inspecting kinetic energy releases and fragment-ion angular distributions.