2,955 research outputs found

    Towards Flight Trials for an Autonomous UAV Emergency Landing using Machine Vision

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    This paper presents the evolution and status of a number of research programs focussed on developing an automated fixed wing UAV landing system. Results obtained in each of the three main areas of research as vision-based site identification, path and trajectory planning and multi-criteria decision making are presented. The results obtained provide a baseline for further refinements and constitute the starting point for the implementation of a prototype system ready for flight testing

    Surgical injury in the neonatal rat alters the adult pattern of descending modulation from the rostroventral medulla

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    Background: Neonatal pain and injury can alter long-term sensory thresholds. Descending rostroventral medulla (RVM) pathways can inhibit or facilitate spinal nociceptive processing in adulthood. As these pathways undergo significant postnatal maturation, the authors evaluated long-term effects of neonatal surgical injury on RVM descending modulation. Methods: Plantar hind paw or forepaw incisions were performed in anesthetized postnatal day (P)3 Sprague-Dawley rats. Controls received anesthesia only. Hind limb mechanical and thermal withdrawal thresholds were measured to 6 weeks of age (adult). Additional groups received pre- and post-incision sciatic nerve levobupivacaine or saline. Hind paw nociceptive reflex sensitivity was quantified in anesthetized adult rats using biceps femoris electromyography, and the effect of RVM electrical stimulation (5–200 μA) measured as percentage change from baseline. Results: In adult rats with previous neonatal incision (n = 9), all intensities of RVM stimulation decreased hind limb reflex sensitivity, in contrast to the typical bimodal pattern of facilitation and inhibition with increasing RVM stimulus intensity in controls (n = 5) (uninjured vs. neonatally incised, P < 0.001). Neonatal incision of the contralateral hind paw or forepaw also resulted in RVM inhibition of hind paw nociceptive reflexes at all stimulation intensities. Behavioral mechanical threshold (mean ± SEM, 28.1 ± 8 vs. 21.3 ± 1.2 g, P < 0.001) and thermal latency (7.1 ± 0.4 vs. 5.3 ± 0.3 s, P < 0.05) were increased in both hind paws after unilateral neonatal incision. Neonatal perioperative sciatic nerve blockade prevented injury-induced alterations in RVM descending control. Conclusions: Neonatal surgical injury alters the postnatal development of RVM descending control, resulting in a predominance of descending inhibition and generalized reduction in baseline reflex sensitivity. Prevention by local anesthetic blockade highlights the importance of neonatal perioperative analgesia

    Synchroniser modeling with application specific to the dual clutch transmission

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    The synchromesh type synchroniser has been introduced to dual clutch transmission applications for gear selection prior to shifting. Historical research into this type of mechanism has targeted the application to manual transmission systems only. Such work targets the phenomena associated with driver feel such as shift effort and ¿double bump¿. Now automated, the control of the synchroniser is less concerned with such aspects of the actuation, focus not trends towards repeatability of the process as well as speed of engagement. The actuation of this type of mechanism relies on the balancing of torques derived from engagement chamfers, the cone clutch and losses experienced in the transmission. These torques affect the displacement of sleeve, asynchronisation of the target gear, as well as the unblocking of synchroniser ring and indexing of the gear to the locked position. Thus a simplified model of the synchroniser mechanism and associated gear is developed for the purpose of simulating its operation in a dual clutch transmission. Unlike similar simulations this model targets the actuation of the mechanism using input forces from the controller, rather than using the control of sleeve displacement to determine maximum forces experience by the driver. To assess how operating characteristics have varied the mechanism has been modelled in the Matlab® environment. This paper presents the techniques used to model the mechanism, including the governing principles of synchroniser actuation and drag torque. Simulation results demonstrate that the primary variation in the mechanism is through the indexing chamfers. Additionally the influence of temperature variation is demonstrated for a fifth gear upshift, and the detrimental effects of cold starts demonstrated

    Optical properties of tissue measured using terahertz pulsed imaging.

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    The first demonstrations of terahertz imaging in biomedicine were made several years ago, but few data are available on the optical properties of human tissue at terahertz frequencies. A catalogue of these properties has been established to estimate variability and determine the practicality of proposed medical applications in terms of penetration depth, image contrast and reflection at boundaries. A pulsed terahertz imaging system with a useful bandwidth 0.5-2.5 THz was used. Local ethical committee approval was obtained. Transmission measurements were made through tissue slices of thickness 0.08 to 1 mm, including tooth enamel and dentine, cortical bone, skin, adipose tissue and striated muscle. The mean and standard deviation for refractive index and linear attenuation coefficient, both broadband and as a function of frequency, were calculated. The measurements were used in simple models of the transmission, reflection and propagation of terahertz radiation in potential medical applications. Refractive indices ranged from 1.5 ± 0.5 for adipose tissue to 3.06 ± 0.09 for tooth enamel. Significant differences (P<0.05) were found between the broadband refractive indices of a number of tissues. Terahertz radiation is strongly absorbed in tissue so reflection imaging, which has lower penetration requirements than transmission, shows promise for dental or dermatological applications

    Medication adherence in patients with myotonic dystrophy and facioscapulohumeral muscular dystrophy

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    Myotonic dystrophy (DM) and facioscapulohumeral muscular dystrophy (FSHD) are the two most common adult muscular dystrophies and have progressive and often disabling manifestations. Higher levels of medication adherence lead to better health outcomes, especially important to patients with DM and FSHD because of their multisystem manifestations and complexity of care. However, medication adherence has not previously been studied in a large cohort of DM type 1 (DM1), DM type 2 (DM2), and FSHD patients. The purpose of our study was to survey medication adherence and disease manifestations in patients enrolled in the NIH-supported National DM and FSHD Registry. The study was completed by 110 DM1, 49 DM2, and 193 FSHD patients. Notable comorbidities were hypertension in FSHD (44 %) and DM2 (37 %), gastroesophageal reflux disease in DM1 (24 %) and DM2 (31 %) and arrhythmias (29 %) and thyroid disease (20 %) in DM1. Each group reported high levels of adherence based on regimen complexity, medication costs, health literacy, side effect profile, and their beliefs about treatment. Only dysphagia in DM1 was reported to significantly impact medication adherence. Approximately 35 % of study patients reported polypharmacy (taking 6 or more medications). Of the patients with polypharmacy, the DM1 cohort was significantly younger (mean 55.0 years) compared to DM2 (59.0 years) and FSHD (63.2 years), and had shorter disease duration (mean 26 years) compared to FSHD (26.8 years) and DM2 (34.8 years). Future research is needed to assess techniques to ease pill swallowing in DM1 and to monitor polypharmacy and potential drug interactions in DM and FSHD

    Inventing and Implementing LLCs at an HBCU in One Year: Lessons Learned

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    Living-Learning Communities (LLCs) have proven to be a successful high impact practice at institutions across the nation. Norfolk State University (NSU), a Historically Black University, recently established a formal LLC program as a part of the University’s Quality Enhancement Plan (QEP). Through a strong partnership with Academic and Student Affairs, NSU implemented and invented LLCs all within one academic year. Similar to the collaborative nature of LLCs, this paper examines the lessons learned from various perspectives (LLC director, teaching dean, faculty liaison, faculty) during the rapid inventing and implementing of LLCs

    UBVRI CCD photometric study of the open clusters Basel 4 and NGC 7067

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    In this paper we present UBVRI CCD photometry in the region of two young open star clusters Basel 4 and NGC 7067 for the first time. Our sample consists of ~ 4000 stars down to V ~ 21 mag. Stellar surface density profile indicates that radius of Basel 4 and NGC 7067 are about 1.8 and 3.0 arcmin respectively.The (U-B) versus (B-V) diagrams indicate that metallicity of NGC 7067 is solar while that of Basel 4 is Z ~ 0.008. We estimate the mean value of E(B-V) = 0.45±\pm0.05 and 0.75±\pm0.05 mag for Basel 4 and NGC 7067 respectively. The analysis of 2MASS JHK data in combination with the optical data in both the clusters yields E(J-K) = 0.30±\pm0.20 mag and E(V-K) = 1.60±\pm0.20 mag for Basel 4 while E(J-K) = 0.40±\pm0.20 mag and E(V-K) = 2.10±\pm0.20 mag for NGC 7067. Furthermore, colour excess diagrams show a normal interstellar extinction law towards both the clusters. Using the intrinsic colour-magnitude diagrams of the cluster members, we estimated the distances of the clusters as 3.0±\pm0.2 and 3.6±\pm0.2 Kpc for Basel 4 and NGC 7067 respectively. By fitting the proper metallicity isochrones to the bright cluster members we estimated the age of the clusters as 200±\pm50 and 100±\pm25 Myr for Basel 4 and NGC 7067 respectively. The mass function slope which is derived by applying the corrections of field star contamination and data incompleteness are 1.55±0.251.55\pm0.25 and 1.68±0.471.68\pm0.47 for Basel 4 and NGC 7067 respectively. The values of mass function slopes are thus not too different from the Salpeter's (1955) value. Mass segregation is observed in both the clusters which may be due to the dynamical evolutions or imprint of star formation processes or both.Comment: 14 pages, 12 figures, Accepted for publication in MNRA

    ¡Stop Acoso! Reacciones de los hombres a la confrontación de las víctimas

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    Sexual harassment is one of the most widespread forms of gender violence. Perceptions of sexual harassment depend on gender, context, the perceivers’ ideology, and a host of other factors. Research has underscored the importance of coping strategies in raising a victim's self-confidence by making her feel that she plays an active role in overcoming her own problems. The aim of this study was to assess the men's perceptions of sexual harassment in relation to different victim responses. The study involved 101 men who were administered a questionnaire focusing on two of the most frequent types of harassment (gender harassment vs. unwanted sexual attention) and victim response (confrontation vs. non confrontation), both of which were manipulated. Moreover, the influences of ideological variables, ambivalent sexism, and the acceptance of myths of sexual harassment on perception were also assessed. The results highlight the complexities involved in recognizing certain behaviors as harassment and the implications of different victim responses to incidents of harassment. As the coping strategies used by women to confront harassment entail drawbacks that pose problems or hinder them, the design and implementation of prevention and/or education programs should strive to raise awareness among men and women to further their understanding of this construct.El acoso sexual es una de las formas más generalizadas de violencia de género. Las percepciones sobre el acoso sexual dependen de factores tales como el género, el contexto y la ideología del perceptor, entre otros. La investigación ha mostrado la importancia que tiene el afrontamiento de la víctima en su nivel de confianza, haciendo que sienta de esta manera que tiene un papel relevante en la solución del problema. El objetivo de este estudio fue indagar en la percepción que los hombres tienen acerca del acoso sexual y de las distintas medidas usadas como respuesta por parte de la víctima. Participaron en el estudio 101 hombres que contestaron un cuestionario en el que se manipulaban dos de los tipos de acoso más frecuentes (acoso de género vs. atención sexual no deseada) así como la respuesta de la víctima (confrontación vs. no confrontación). También se estudió la influencia en dicha percepción de variables ideológicas como el sexismo ambivalente y la aceptación de los mitos sobre el acoso sexual. Los resultados resaltan la dificultad de reconocer determinados comportamientos como acoso, así como las posibles consecuencias que puede sufrir la víctima en función de la respuesta que dé a estas situaciones de acoso. Las estrategias usadas por las mujeres para afrontar el acoso parecen presentar algún obstáculo o problema para ellas, por lo que se hace necesaria la implantación de programas preventivos y/o educativos con el fin de enseñar a hombres y mujeres a comprender mejor el constructo.Open Access funded by Colegio Oficial de Psicólogos de MadridThis research was supported by the Spanish Ministry of Economy and Competitiveness with the R&D project “Sexist ideology and power inequality in the development and maintenance of Sexual Harassment” (PSI2011-29720), by Grant SEJ-6225 “Psychosocial analysis of legitimacy and prejudice in the maintenance of asymmetrical social relationships” from the Andalusian Regional Govemment, and by a Grant from the FPU (AP2009-2940) Program of the Spanish Ministry of Education, Culture and Sport given to the second author

    A comprehensive CCD photometric study of the open cluster NGC 2421

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    We present the UBVRIUBVRI CCD photometry in the region of the open cluster NGC 2421. Radius of the cluster is determined as \sim 3^\prime.0 using stellar density profile. Our Study indicates that metallicity of the cluster is ZZ \sim 0.004. The reddening E(BV)=0.42±E(B-V) = 0.42\pm0.05 mag is determined using two colour (UB)(U-B) versus (BV)(B-V) diagram. By combining the 2MASS JHKJHK data with the optical data we determined E(JK)=0.20±E(J-K) = 0.20\pm0.20 mag and E(VK)=1.15±E(V-K) = 1.15\pm0.20 mag for this cluster. Colour-excess diagrams show normal interstellar extinction law in the direction of the cluster. We determined the distance of the cluster as 2.2±\pm0.2 Kpc by comparing the ZAMS with the intrinsic CM diagram of the cluster. The age of the cluster has been estimated as 80±\pm20 Myr using the stellar isochrones of metallicity Z=0.004Z = 0.004. The mass function slope x=1.2±0.3x = 1.2\pm0.3 has been derived by applying the corrections of field stars contamination and data incompleteness. Our analysis indicate that the cluster NGC 2421 is dynamically relaxed.Comment: 10 pages, 13 figures, Accepted for publication in MNRA
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