225 research outputs found

    Orbital non-Fermi-liquid behavior in cubic ruthenates

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    We peruse various anomalous physical responses of the cubic (ferromagnetic SrRuO3 and paramagnetic CaRuO3) ruthenates, such as fractional power-law conductivity, anomalous Raman line shapes, and Hall currents. We show how these exciting power-law observations are naturally described within a new, local (orbital) non-Fermi-liquid state arising from strong, multiorbital Coulomb interactions. Introducing a multiorbital, correlated model treated within the dynamical mean-field theory, we also find two distinct relaxation rates for relaxation of transport in complete agreement with experiment

    The impact of environmental noise on robot-assisted laparoscopic surgical performance

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    Background. An operating room is a noisy environment. How noise affects performance during robotic surgery remains unknown. We investigated whether noise during training with the da Vinci surgical robot (Intuitive Surgical, Inc., Sunnyvale, CA) would affect the performance of simple operative tasks by the surgeon. Methods. Twelve medical students performed 3 inanimate operative tasks (bimanual carrying, suture tying, and mesh alignment) on the da Vinci Surgical System with or without the presence of noise. Prerecorded noise from an actual operating room was used. The kinematics of the robotic surgical instrument tips and the muscle activation patterns of the subjects were evaluated. Results. We found noise effects for all 3 tasks with increases in the time to task completion (23%; P = .046), the total distance traveled (8%; P = .011) of the surgical instrument tips, and the muscle activation volume (87%; P = .015) with the presence of noise. We confirmed that the mesh alignment task was the most difficult task with the greatest time to task completion and the greatest muscle activation volume, whereas the suture tying task and the bimanual carrying could be considered the intermediate and the least difficult task, respectively. The noise effects were significantly greater while performing more difficult tasks. Conclusion. Our findings demonstrated that noise degraded robotic surgical performance; however, the impact of noise on robotic surgery will depend on the level of difficulty of the task. Subsequent research is required to identify how different types of noise, such as random or rhythmic sounds, affect the performance of operative tasks using robots such as the da Vinci

    The Effect of Music on Robot-Assisted Laparoscopic Surgical Performance

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    Music is often played in the operating room to increase the surgeon’s concentration and to mask noise. It could have a beneficial effect on surgical performance. Ten participants with limited experience with the da Vinci robotic surgical system were recruited to perform two surgical tasks: suture tying and mesh alignment when classical, jazz, hip-hop, and Jamaican music were presented. Kinematics of the instrument tips of the surgical robot and surface electromyography of the subjects were recorded. Results revealed that a significant music effect was found for both tasks with decreased time to task completion (P = .005) and total travel distance (P = .021) as well as reduced muscle activations ( P = .016) and increased median muscle frequency (P = .034). Subjects improved their performance significantly when they listened to either hip-hop or Jamaican music. In conclusion, music with high rhythmicity has a beneficial effect on robotic surgical performance. Musical environment may benefit surgical training and make acquisition of surgical skills more efficient

    Structural and magnetic properties of co-sputtered Fe0.8C0.2 thin films

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    We studied the structural and magnetic properties of \FeC~thin films deposited by co-sputtering of Fe and C targets in a direct current magnetron sputtering (dcMS) process at a substrate temperature (\Ts) of 300, 523 and 773\,K. The structure and morphology was measured using x-ray diffraction (XRD), x-ray absorption near edge spectroscopy (XANES) at Fe LL and C KK-edges and atomic/magnetic force microscopy (AFM, MFM), respectively. An ultrathin (3\,nm) 57^{57}\FeC~layer, placed between relatively thick \FeC~layers was used to estimate Fe self-diffusion taking place during growth at different \Ts~using depth profiling measurements. Such 57^{57}\FeC~layer was also used for 57^{57}Fe conversion electron M\"{o}ssbauer spectroscopy (CEMS) and nuclear resonance scattering (NRS) measurements, yielding the magnetic structure of this ultrathin layer. We found from XRD measurements that the structure formed at low \Ts~(300\,K) is analogous to Fe-based amorphous alloy and at high \Ts~(773\,K), pre-dominantly a \tifc~phase has been formed. Interestingly, at an intermediate \Ts~(523\,K), a clear presence of \tefc~(along with \tifc~and Fe) can be seen from the NRS spectra. The microstructure obtained from AFM images was found to be in agreement with XRD results. MFM images also agrees well with NRS results as the presence of multi-magnetic components can be clearly seen in the sample grown at \Ts~= 523\,K. The information about the hybridization between Fe and C, obtained from Fe LL and C KK-edges XANES also supports the results obtained from other measurements. In essence, from this work, experimental realization of \tefc~has been demonstrated. It can be anticipated that by further fine-tuning the deposition conditions, even single phase \tefc~phase can be realized which hitherto remains an experimental challenge.Comment: 11 pages, 9 figure

    Enhancing Fundamental Robot-Assisted Surgical Proficiency by Using a Portable Virtual Simulator

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    Background. The development of a virtual reality (VR) training platform provides an affordable interface. The learning effect of VR and the capability of skill transfer from the VR environment to clinical tasks require more investigation. Methods. Here, 14 medical students performed 2 fundamental surgical tasks—bimanual carrying (BC) and peg transfer (PT)—in actual and virtual environments. Participants in the VR group received VR training, whereas participants in the control group played a 3D game. The learning effect was examined by comparing kinematics between pretraining and posttraining in the da Vinci Surgical System. Differences between VR and playing the 3D game were also examined. Results. Those who were trained with the VR simulator had significantly better performance in both actual PT (P = .002) and BC (P \u3c .001) tasks. The time to task completion and the total distance traveled were significantly decreased in both surgical tasks in the VR group compared with the 3D game group. However, playing the 3D game showed no significant enhancement of fundamental surgical skills in the actual PT task. The difference between pretraining and posttraining was significantly larger in the VR group than in the 3D game group in both the time to task completion (P = .002) and the total distance traveled (P = .027) for the actual PT task. Participants who played the 3D game seemed to perform even worse in posttraining. Conclusions. Training with the portable VR simulator improved robot-assisted surgical skill proficiency in comparison to playing a 3D game

    Skills Learning in Robot-Assisted Surgery Is Benefited by Task-Specific Augmented Feedback

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    Background: Providing augmented visual feedback is one way to enhance robot-assisted surgery (RAS) training. However, it is unclear whether task specificity should be considered when applying augmented visual feedback. Methods: Twenty-two novice users of the da Vinci Surgical System underwent testing and training in 3 tasks: simple task, bimanual carrying (BC); intermediate task, needle passing (NP); and complex task, suture tying (ST). Pretraining (PRE), training, and posttraining (POST) trials were performed during the first session. Retention trials were performed 2 weeks later (RET). Participants were randomly assigned to 1 of 4 feedback training groups: relative phase (RP), speed, grip force, and video feedback groups. Performance measures were time to task completion (TTC), total distance traveled (D), speed (S), curvature, relative phase, and grip force (F). Results: Significant interaction for TTC and curvature showed that the RP feedback training improved temporal measures of complex ST task compared to simple BC task. Speed feedback training significantly improved the performance in simple BC task in terms of TTC, D, S, curvature, and F even after retention. There was also a lesser long-term effect of speed feedback training on complex ST task. Grip force feedback training resulted in significantly greater improvements in TTC and curvature for complex ST task. For the video feedback training group, the improvements in most of the outcome measures were evident only after RET. Conclusions: Task-specific augmented feedback is beneficial to RAS skills learning. Particularly, the RP and grip force feedback could be useful for training complex tasks

    \u3ci\u3eMedicine Meets Virtual Reality 17\u3c/i\u3e

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    Chapter, A Virtual Reality Training Program for Improvement of Robotic Surgical Skills, co-authored by Mukul Mukherjee and Nicholas Stergiou, UNO faculty members. Chapter, Consistency of Performance of Robot-Assisted Surgical Tasks in Virtual Reality, co-authored by Mukul Mukherjee and Nicholas Stergiou, UNO faculty members. The 17th annual Medicine Meets Virtual Reality (MMVR17) was held January 19-22, 2009, in Long Beach, CA, USA. The conference is well established as a forum for emerging data-centered technologies for medical care and education. Each year, it brings together an international community of computer scientists and engineers, physicians and surgeons, medical educators and students, military medicine specialists and biomedical futurists. MMVR emphasizes inter-disciplinary collaboration in the development of more efficient and effective physician training and patient care. The MMVR17 proceedings collect 108 papers by conference lecture and poster presenters. These papers cover recent developments in biomedical simulation and modeling, visualization and data fusion, haptics, robotics, sensors and other related information-based technologies. Key applications include medical education and surgical training, clinical diagnosis and therapy, physical rehabilitation, psychological assessment, telemedicine and more. From initial vision and prototypes, through assessment and validation, to clinical and academic utilization and commercialization - MMVR explores the state-of-the-art and looks toward healthcare’s future. The proceedings volume will interest physicians, surgeons and other medical professionals interested in emerging and future tools for diagnosis and therapy; educators responsible for training the next generation of doctors and scientists; IT and medical device engineers creating state-of-the-art and next-generation simulation, imaging, robotics and communication systems; data technologists creating systems for gathering, processing and distributing medical intelligence; military medicine specialists addressing the challenges of warfare and defense health needs; and biomedical futurists and investors who want to understand where the field is headed.https://digitalcommons.unomaha.edu/facultybooks/1233/thumbnail.jp

    Implications of ecotourism development in protected areas: A study from Rema-Kalenga Wildlife Sanctuary, Bangladesh

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    This article is based on visitors profile study of protected area based tourist spots of Rema-Kalenga Wildlife Sanctuary (RKWS), Bangladesh to ascertain the potential of ecotourism. Study findings shows that 69% male constitute the visitors group while the maximum number of visitors was found in the age of below 30 years. Most of the visitors were literate and among them 43% visitors were student. Most (53%) of visitors preferred to get recreation in holidays as they were employed. Visitors were highly preferred to come with friends group. About 92% respondents showed positive mind to come here in future while 89% respondents view that park has tourism potential. Most of the respondents reported the presence of wildlife (48%) most notable followed by plant diversity and tribal community as recreational. From χ2 test it is found that highly significance association present between tourism potentiality of the wildlife sanctuary and some demographic variable like income of tourists (χ2 = 49.138, p < 0.000), visiting pattern (χ2 = 19.344, p < 0.000), education of tourists (χ2 = 50.226, p < 0.000), travelling distance (Km - χ2 = 11.427, p < 0.022), duration of staying (χ2 = 12.867, p < 0.002), frequency of visit (χ2 = 8.456, p < 0.015), visiting time (χ2 = 6.530, p < 0.011), problem in the study area (χ2 = 14.962, p < 0.021), occupation of tourists (χ2 = 8.848, p < 0.031). If the problems addressed by the visitors were solved, RKWS would be a bright place of eco-tourism in Bangladesh

    Integrating livelihoods and conservation in protected areas: Understanding the role and stakeholder views on prospects for non-timber forest products, a Bangladesh case study

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    Protected areas (PAs) represent a key global strategy in biodiversity conservation. In tropical developing countries, the management of PAs is a great challenge as many contain resources on which local communities rely. Collection and trading of non-timber forest products (NTFPs) is a well-established forest-based livelihood strategy, which has been promoted as a potential means for enhanced conservation and improved rural livelihoods in recent years, even though the sustainability or ecological implications have rarely been tested. We conducted an exploratory survey to understand the role and stakeholder views on conservation prospects and perceived ecological feasibility of NTFPs and harvesting schemes in a northeastern PA of Bangladesh, namely the Satchari National Park. Households (n = 101) were interviewed from three different forest dependency categories, adopting a stratified random sampling approach and using a semi-structured questionnaire. The study identified 13 locally important NTFPs, with five being critically important to supporting local livelihoods. Our study suggests that collection, processing and trading in NTFPs constitutes the primary occupation for about 18% of local inhabitants and account for an estimated 19% of their cash annual income. The household consensus on issues relating to NTFPs and their prospective role in conservation was surprisingly high, with 48% of respondents believing that promotion of NTFPs in the PA could have positive conservation value. The majority (71%) of households also had some understanding of the ecological implications of NTFP harvesting, sustainability (53%) and possible management and monitoring regimes (100%). With little known about their real application in the field, our study suggests further investigations are required to understand the ecological compatibility of traditional NTFP harvesting patterns and management. © 2010 Taylor & Francis
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