7,465 research outputs found

    Fault-tolerant formation driving mechanism designed for heterogeneous MAVs-UGVs groups

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    A fault-tolerant method for stabilization and navigation of 3D heterogeneous formations is proposed in this paper. The presented Model Predictive Control (MPC) based approach enables to deploy compact formations of closely cooperating autonomous aerial and ground robots in surveillance scenarios without the necessity of a precise external localization. Instead, the proposed method relies on a top-view visual relative localization provided by the micro aerial vehicles flying above the ground robots and on a simple yet stable visual based navigation using images from an onboard monocular camera. The MPC based schema together with a fault detection and recovery mechanism provide a robust solution applicable in complex environments with static and dynamic obstacles. The core of the proposed leader-follower based formation driving method consists in a representation of the entire 3D formation as a convex hull projected along a desired path that has to be followed by the group. Such an approach provides non-collision solution and respects requirements of the direct visibility between the team members. The uninterrupted visibility is crucial for the employed top-view localization and therefore for the stabilization of the group. The proposed formation driving method and the fault recovery mechanisms are verified by simulations and hardware experiments presented in the paper

    The association of appendicular lean mass and grip strength with low-density lipoprotein, very low-density lipoprotein, and high-density lipoprotein particle diameter: a Mendelian randomization study of the UK Biobank cohort

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    Reduced muscle mass and reduced strength are frequently associated with both alterations in blood lipids and poorer cardiometabolic outcomes in epidemiological studies; however, a causal association cannot be determined from such observations. Two-sample Mendelian randomization (MR) was applied to assess the association of genetically determined appendicular lean mass (ALM) and handgrip strength (HGS) with serum lipid particle diameter.Methods and resultsMendelian randomization was implemented using summary-level data from the largest genome-wide association studies on ALM (n = 450 243), HGS (n = 223 315), and lipoprotein [low-density lipoprotein (LDL), very LDL (VLDL), and high-density lipoprotein (HDL)] particle diameters (n = 115 078). Inverse variance-weighted (IVW) method was used to calculate the causal estimates. Weighted median-based method, MR-Egger, and leave-one-out method were applied as sensitivity analysis. Greater ALM had a statistically significant positive effect on HDL particle diameter (MR-Egger: β = 0.055, SE = 0.031, P = 0.081; IVW: β = 0.068, SE = 0.014, P < 0.001) and a statistically significant negative effect on VLDL particle diameter (MR-Egger: β = −0.114, SE = 0.039, P = 0.003; IVW: β = −0.081, SE = 0.017, P < 0.001). Similarly, greater HGS had a statistically significant positive effect on HDL particle diameter (MR-Egger: β = 0.433, SE = 0.184, P = 0.019; IVW: β = 0.121, SE = 0.052, P = 0.021) and a statistically significant negative effect on VLDL particle diameter (MR-Egger: β = −0.416, SE = 0.163, P = 0.011; IVW: β = −0.122, SE = 0.046, P = 0.009). There was no statistically significant effect of either ALM or HGS on LDL particle diameter.ConclusionThere were potentially causal associations between both increasing ALM and HGS and increasing HDL particle size and decreasing VLDL particle size. These causal associations may offer possibilities for interventions aimed at improving cardiovascular disease risk profile

    Health coaching to encourage obese adults to enroll in commercially-available weight management programs: The path to health study

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    Physicians are recommended to screen and refer obese patients to weight management programs (WMPs). There are often limited referral options for physicians, though commercially-available WMPs could be a potential solution. The purpose of this study (Path to Health) was to evaluate the efficacy of health coaching to promote enrollment in commercially-available WMPs through a two-arm, RCT with obese patients (n = 168) randomly assigned to intervention (n = 84) or control groups (n = 84). Intervention participants received phone health coaching to help them select and enroll in WMPs. We collected data on program enrollment, weight, self-reported physical activity (PA), and fruit and vegetable (FV) intake at baseline, 3- and 6-months. We used logistic regression to assess the intervention effect on enrollment in WMPs and longitudinal regression models to evaluate the effect on weight change, PA and FV intake. The average age was 54.7 years, 59% were female and 43% were Black and 49% were White. At 6 months, 39% of the intervention group (vs. 29% of control) had enrolled in WMPs. We found no longitudinal intervention effect on weight, PA and FV intake. We found that there was more weight loss for those who completed ≥4 calls as compared to those who completedstudy, we found that phone health coaching was successful in increasing obese adults\u27 enrollment in commercially-available WMPs and that there was a dose response relationship for weight and behavioral outcomes

    Land Use and Land Cover Changes in the Diversity and Life Zone for Uncontacted Indigenous People: Deforestation Hotspots in the Yasuní Biosphere Reserve, Ecuadorian Amazon

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    Land use and land cover change (LULC) is an essential component for the monitoring environmental change and managing natural resources in areas of high natural and cultural biodiversity, such as the Amazon biome. This study was conducted in in the northern Amazon of Ecuador, specifically in the Diversity and Life Zone (DLZ) of the Yasuní Biosphere Reserve (YBR). The general aim was to investigate the territorial dynamics of land use/land cover changes to support policies for environmental and sociocultural protection in the DLZ. Specific objectives included (i) mapping LULC spatial and temporal dynamics in the DLZ in the period from 1999 to 2018, (ii) identifying sensitive LULC hotspots within the DLZ, and (iii) defining the possible policy implications for sustainable land use in the DLZ. Multitemporal satellite imagery from the Landsat series was used to map changes in LULC, which were divided into three-time stages (1999–2009, 2009–2018, 1999–2018). We adopted open-access Landsat images downloaded from the United States Geological Survey (USGS). The processes for assessing LULC in the DLZ included (1) data collection and analysis, (2) data processing for remote sensing, (3) thematic land cover, and (4) homogenization and vectorization of images. The results showed that in the period 1999–2018, most of the uses and land cover were transformed into pastures in the DLZ. Therefore, it is important to improve territorial planning, to avoid conflicts between indigenous populations, migrant settlers, and uncontacted indigenous populations that live in the DLZ, within the YBR

    Mexican-American perspectives on participation in clinical trials: A qualitative study

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    AbstractClinical trials are essential to advancing knowledge to reduce disease morbidity and mortality; however, ethnic and racial minorities remain under-represented in those studies. We explored knowledge and perceptions of clinical trials among Mexican-Americans in Texas. We conducted focus groups (N = 128) stratified by gender, language preference, and geographical location. This paper presents four emergent, primary themes: 1) knowledge and understanding of clinical trials, 2) fears and concerns about participating, 3) perceived benefits of participating, and 4) incentives to participate. Results suggest that lack of knowledge and understanding of clinical trials leads to misunderstanding about research, including fears and lack of trust. Participants indicated that fears related to perceived experimentation, harm, immigration status, and lack of clinical trial opportunities within their communities were barriers to participation. On the other hand, free healthcare access, helping family members in the future, and monetary incentives could facilitate participation. We also found differences across themes by language, gender, and place of residence. Findings from our study could inform the development of interventions to enhance recruitment of Mexican-American participants into clinical trials

    Exploration of Latina/Hispanic Women\u27s Experiences Living With Non-Alcoholic Fatty Liver Disease: a Qualitative Study With Patients in Houston

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    OBJECTIVES: A deeper understanding of the lived experiences of Hispanic patients with non-alcoholic fatty liver disease (NAFLD) can help guide the development of behavioral programs that facilitate NAFLD management. This paper explores Hispanic women\u27s experiences living with NAFLD. DESIGN, SETTING, PARTICIPANTS: We collected brief sociodemographic questionnaires and conducted in-depth interviews with 12 low-income (all had household income ≤USD$55 000 per year) Hispanic women with NAFLD from the Houston area. Transcripts were audio-recorded and transcribed. We developed a coding scheme and used thematic analysis to identify emergent themes, supported by Atlas.ti. RESULTS: Participants identified physicians as their main information source on NAFLD but also consulted the internet, family, friends and peers. Many were still left wanting more information. Participants identified family history, sedentary lifestyles, poor diet and comorbid conditions as causes for their NAFLD. Participants also reported emotional distress after diagnosis. Participants experienced both successes and challenges in making lifestyle changes in nutrition and physical activity. Some participants received desired social support in managing NAFLD, although there were conflicting feelings about spousal support. CONCLUSION: Multifaceted programming that improves patient-provider communication, conveys accurate information and enhances social support is needed to support Hispanic women in managing NAFLD

    Understanding Primary Care Physician Perspectives On the Diagnosis and Management of Non-Alcoholic Fatty Liver Disease: a Qualitative Study

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    Primary care physicians (PCPs) are well suited to manage patients with non-alcoholic fatty liver disease (NAFLD), but the limited, existing research suggests inadequate knowledge about the natural history, diagnostic methods, and management of NAFLD. The purpose of this qualitative study is to further understand the knowledge and practices for the diagnosis and management of NAFLD among PCPs. We conducted in-depth interviews with PCPs in the Greater Houston area, addressing current clinical practices used for diagnosing and managing NAFLD, as well as the perceptions of the PCPs regarding the burden of NAFLD on patients. We recorded interviews, transcribed them, coded transcripts, and identified patterns and themes. The interviewed PCPs (n = 16) were from internal or family medicine, with a range of experience (1.5-30 years). We found variations in NAFLD diagnosis and management across practices and by insurance status. Patients with abnormal liver imaging who had insurance or were within a safety-net healthcare system were referred by PCPs to specialists. Uninsured patients with persistently elevated liver enzymes received lifestyle recommendations from PCPs without confirmatory imaging or specialist referral. The role of PCPs in NAFLD management varied, with some helping patients set dietary and physical activity goals while others provided only general recommendations and/or referred patients to a dietitian. The diagnosis and management of NAFLD vary widely among PCPs and may be impacted by patients\u27 insurance status and clinic-specific practices. The increasing burden of NAFLD in the U.S. medical system highlights the need for more PCPs involvement in managing NAFLD

    Admission Control Policies in Multiservice Cellular Networks: Optimum Configuration and Sensitivity

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    Abstract. We evaluate different call admission control policies in various mul-tiservice cellular scenarios. For each of the studied policies we obtain the maximum calling rate that can be offered to the system to achieve a given QoS objective defined in terms of blocking probabilities. We propose an optimiza-tion methodology based on a hill climbing algorithm to find the optimum con-figuration for most policies. The results show that policies of the trunk reserva-tion class outperform policies that produce a product-form solution and the im-provement ranges approximately between 5 and 15 % in the scenarios studied.
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