663 research outputs found

    Takeoff and landing on slopes via inclined hovering with a tethered aerial robot

    Get PDF
    In this paper we face the challenging problem of takeoff and landing on sloped surfaces for a VTOL aerial vehicle. We define the general conditions for a safe and robust maneuver and we analyze and compare two classes of methods to fulfill these conditions: free-flight vs. passivelytethered. Focusing on the less studied tethered method, we show its advantages w.r.t. the free-flight method thanks to the possibility of inclined hovering equilibria. We prove that the tether configuration and the inclination of the aerial vehicle w.r.t. the slope are flat outputs of the system and we design a hierarchical nonlinear controller based on this property. We then show how this controller can be used to land and takeoff in a robust way without the need of either a planner or a perfect tracking. The validity and applicability of the method in the real world is shown by experiments with a quadrotor that is able to perform a safe landing and takeoff on a sloped surface

    Force-based Pose Regulation of a Cable-Suspended Load Using UAVs with Force Bias

    Get PDF

    The three-body recombination of a condensed Bose gas near a Feshbach resonance

    Full text link
    In this paper, we study the three-body recombination rate of a homogeneous dilute Bose gas with a Feshbach resonance at zero temperature. The ground state and excitations of this system are obtained. The three-body recombination in the ground state is due to the break-up of an atom pair in the quantum depletion and the formation of a molecule by an atom from the broken pair and an atom from the condensate. The rate of this process is in good agreement with the experiment on 23^{23}Na in a wide range of magnetic fields.Comment: 10 pages, 2 figures, to be published in Phys. Rev.

    Analysis of caesarean section and neonatal outcome using the Robson classification in a rural district hospital in Tanzania: An observational retrospective study

    Get PDF
    OBJECTIVE: Caesarean section (CS) rates have increased worldwide in recent decades. In 2015, the WHO proposed the use of the 10-group Robson classification as a global standard for assessing, monitoring and comparing CS rates both within healthcare facilities over time and between them. The aim of this study was to assess the pattern of CS rates according to the Robson classification and describe maternal and perinatal outcomes by group at the Tosamaganga Hospital in rural Tanzania. DESIGN: Observational retrospective study. SETTING: St. John of the Cross Tosamaganga Hospital, a referral centre in rural Tanzania. PARTICIPANTS: 3012 women who gave birth in Tosamaganga Hospital from 1 January to 30 June 2014 and from 1 March to 30 November 2015. RESULTS: The overall CS rate was 35.2%, and about 90% of women admitted for labour were in Robson groups 1 through 5. More than 40% of the CS carried out in the hospital were performed on nulliparous women at term with a single fetus in cephalic presentation (groups 1 and 3), and the most frequent indication for the procedure was previous uterine scar (39.2%). The majority of severe neonatal outcomes were observed in groups 1 (27.7%), 10 (24.5%) and 3 (19.1%). CONCLUSION: We recorded a high CS rate in Tosamaganga Hospital, particularly in low-risk patients groups (Robson groups 1 and 3). Our analysis of Robson classification and neonatal outcomes suggests the need to improve labour management at the hospital and to provide timely referrals in order to prevent women from arriving there in critical conditions

    Adherence to a Mediterranean-like dietary pattern in children from eight European countries : the IDEFICS study

    Get PDF
    BACKGROUND: Despite documented benefits of a Mediterranean-like dietary pattern, there is a lack of knowledge about how children from different European countries compare with each other in relation to the adherence to this pattern. In response to this need, we calculated the Mediterranean diet score (MDS) in 2-9-year-old children from the Identification and prevention of dietary-and lifestyle-induced health effects in children and infants (IDEFICS) eight-country study. SUBJECTS AND METHODS: Using 24 h dietary recall data obtained during the IDEFICS study (n = 7940), an MDS score was calculated based on the age- and sex-specific population median intakes of six food groups (vegetables and legumes, fruit and nuts, cereal grains and potatoes, meat products and dairy products) and the ratio of unsaturated to saturated fats. For fish and seafood, which was consumed by 10% of the population, one point was given to consumers. The percentages of children with high MDS levels (43) were calculated and stratified by sex, age and by having at least one migrant parent or both native parents. Demographic (sex and age) and socioeconomic characteristics (parental education and income) of children showing high (43) vs low (<= 3) MDS levels were examined. RESULTS: The highest prevalence of children with MDS 43 was found among the Italian pre-school boys (55.9%) and the lowest among the Spanish school-aged girls (26.0%). Higher adherence to a Mediterranean-like dietary pattern was not associated with living in a Mediterranean country or in a highly educated or high-income family, although with some exceptions. Differences in adherence between boys and girls or age groups varied between countries without any general pattern. CONCLUSIONS: With the exception of Italian pre-schoolers, similar adherence levels to a Mediterranean-like dietary pattern have been observed among European children

    Enhancement of the Biological and Mechanical Performances of Sintered Hydroxyapatite by Multiple Ions Doping

    Get PDF
    In the present work, hydroxyapatite (HA) nanoparticles doped with Mg2+, Sr2+, and Zn2+ ions are developed by wet neutralization method and then sintered at 1,250°C to obtain bulk consolidated materials. Physicochemical and microstructural analyses show that the presence of doping ions in the HA structure induced the formation of βTCP as secondary phase, during the sintering process, and we found that this effect is depending on the stability of the various doping ions in the hydroxyapatite lattice itself. We also found that the formation of βTCP as secondary phase, in turn, confines the grain growth of HA induced by the high-temperature sintering process, thus leading to a strong increase of the flexural strength of the bulk materials, according to Hall-Petch-like law. Furthermore, we found that the doping ions enter also in the structure of the βTCP phase; besides the grain growth confinement, also the solubility and ion release ability of the final materials were enhanced. In addition to ameliorate the mechanical performance, the described phenomena also activate multiple biofunctionalities: (i) ability to upregulate various genes involved in the osteogenesis, as obtained by human adipose stem cells culture and evaluated by array technology; (ii) enhanced resistance to the adhesion and proliferation of Gram+ and Gram– bacterial strains. Hence, our results open a perspective for the use of sintered multiple ion-doped HA to develop ceramic biodevices, such as plates, screws, or other osteosynthesis media, with enhanced strength, osteointegrability, and the ability to prevent post-surgical infections

    Associations between energy intake, daily food intake and energy density of foods and BMI z-score in 2-9-year-old European children

    Get PDF
    The aim of this study was to investigate the associations between proxy-reported energy intake, daily food intake and energy density of foods and body mass index (BMI) z-score in 2-9-year-old European children. From 16,225 children who participated in the identification and prevention of dietary- and lifestyle-induced health effects in children and infants (IDEFICS) baseline examination, 9,782 children with 24-h proxy dietary information and complete covariate information were included in the analysis. Participating children were classified according to adapted Goldberg cutoffs: underreports, plausible energy reports and overreports. Energy intake, daily food intake and energy density of foods excluding noncaloric beverages were calculated for all eating occasions. Effect of energy intake, daily food intake and energy density of foods on BMI z-score was investigated using multilevel regression models in the full sample and subsample of plausible energy reports. Exposure variables were included separately; daily food intake and energy intake were addressed in a combined model to check for interactions. In the group of plausible energy reports (N = 8,544), energy intake and daily food intake were significantly positively associated with BMI z-score. Energy density of foods was not associated with BMI z-score. In the model including energy intake, food intake and an interaction term, only energy intake showed a significantly positive effect on BMI z-score. In the full sample (N = 9,782), only energy intake was significantly but negatively associated with BMI z-score. Proxy-reporters are subject to misreporting, especially for children in the higher BMI levels. Energy intake is a more important predictor of unhealthy weight development in children than daily food intake

    Etude Des Facteurs De Risque De L’obésité Chez Le Personnel Du CHUD/Borgou à Parakou (Bénin) en 2013

    Get PDF
    The objective of this study was to determine the prevalence of obesity among employees CHUD in Parakou and risk factors in 2013. Methods: This was a cross sectional study, descriptive analytical referred to place from 05 August to 05 September 2013. The study population consists of employees of CHUD in Parakou. Data were collected using a questionnaire and by anthropometric measures. Results: The overall prevalence of overweight and obesity was 55.9%. The sex ratio was 0.8. The mean age of subjects was 37.2 ± 9.0 years. Factors associated with obesity were: female gender (p = 10-11), those aged 30-49 years (p = 0.04), subjects with a level of secondary education limited (p = 0.01), subjects with a daily consumption and accidental alcohol (p = 10-9), snacking (p = 0.00012). Conclusion: Obesity prevention should involve the establishment and maintenance during the lifetime of healthy eating habits and regular physical activity

    Methylglyoxal, Glycated Albumin, PAF, and TNF-&#945;: Possible Inflammatory and Metabolic Biomarkers for Management of Gestational Diabetes

    Get PDF
    Background: In gestational diabetes mellitus (GDM), pancreatic \u3b2-cell breakdown can result from a proinflammatory imbalance created by a sustained level of cytokines. In this study, we investigated the role of specific cytokines, such as B-cell activating factor (BAFF), tumor necrosis factor \u3b1 (TNF-\u3b1), and platelet-activating factor (PAF), together with methylglyoxal (MGO) and glycated albumin (GA) in pregnant women affected by GDM. Methods: We enrolled 30 women whose inflammation and metabolic markers were measured at recruitment and after 12 weeks of strict dietetic therapy. We compared these data to the data obtained from 53 randomly selected healthy nonpregnant subjects without diabetes, hyperglycemia, or any condition that can affect glycemic metabolism. Results: In pregnant women affected by GDM, PAF levels increased from 26.3 (17.4-47.5) ng/mL to 40.1 (30.5-80.5) ng/mL (p &lt; 0.001). Their TNF-\u3b1 levels increased from 3.0 (2.8-3.5) pg/mL to 3.4 (3.1-5.8) pg/mL (p &lt; 0.001). The levels of methylglyoxal were significantly higher in the women with GDM (p &lt; 0.001), both at diagnosis and after 12 weeks (0.64 (0.46-0.90) \u3bcg/mL; 0.71 (0.47-0.93) \u3bcg/mL, respectively) compared to general population (0.25 (0.19-0.28) \u3bcg/mL). Levels of glycated albumin were significantly higher in women with GDM (p &lt; 0.001) only after 12 weeks from diagnosis (1.51 (0.88-2.03) nmol/mL) compared to general population (0.95 (0.63-1.4) nmol/mL). Conclusion: These findings support the involvement of new inflammatory and metabolic biomarkers in the mechanisms related to GDM complications and prompt deeper exploration into the vicious cycle connecting inflammation, oxidative stress, and metabolic results

    Olfactometric techniques in feed analysis: preliminary calibration of DON in durum wheat

    Get PDF
    Approcci olfattometrici nell\u2019analisi dei mangimi: calibrazione preliminare per il rilievo di DON nel grano duro. Le analisi olfattometriche, attraverso l\u2019uso del naso elettronico, trovano sempre pi\uf9 spazio nella valutazione della qualit\ue0 e sicurezza in campo alimentare. I principali vantaggi di tale approccio risiedono nella sua flessibilit\ue0 di impiego. Una volta messi a punto adeguati protocolli d\u2019analisi e modelli statistici di tipo multivariato, infatti, il naso elettronico si pu\uf2 rivelare uno strumento adatto alle realt\ue0 di campo in quanto caratterizzato da rapidit\ue0 e basso costo d\u2019esercizio. Lo scopo di questo lavoro \ue8 stato quello di verificare, a livello preliminare, l\u2019efficienza del naso elettronico nel riconoscere la presenza di micotossina deossinivalenolo (DON) in 10 campioni di grano duro (Triticum durum) di diversa provenienza geografica. I risultati hanno dimostrato che il protocollo applicato consente di riconoscere la presenza di DON nonch\ue9 di discriminare i diversi campioni in funzione del loro livello di contaminazione
    corecore