162 research outputs found
Simplified Metrics Calculation for Soft Bit Detection in DVB-T2
The constellation rotation and cyclic quadrature component delay (RQD) technique has been adopted in the second generation terrestrial digital video broadcasting (DVB-T2) standard. It improves the system performance under severe propagation conditions, but introduces serious complexity problems in the hardware implementation of the detection process. In this paper, we present a simplified scheme that greatly reduces the complexity of the demapper by simplifying the soft bit metrics computation having a negligible overall system performance loss
Heliophysics Portal - Multi-Instrument Database of Solar Flares
No abstract availabl
Avaliação da produção lacrimal em gambás filhotes por três diferentes métodos
O estabelecimento do parâmetro de produção lacrimal nas diferentes espĂ©cies Ă© importante para o entendimento da saĂşde do olho e Ă© um dos componentes da semiotĂ©cnica oftálmica. Particularidades derivadas da anatomofisiologia das espĂ©cies nĂŁo domĂ©sticas induzem a busca de metodologias que sejam mais fidedignas aos parâmetros. Objetivou-se com este estudo avaliar e comparar a produção lacrimal de gambás-de-orelha-branca (Didelphis albiventris) e gambás-de-orelha-preta (Didelphis aurita) por trĂŞs diferentes mĂ©todos. Quinze indivĂduos de cada espĂ©cie, juvenis, hĂgidos, de ambos os sexos, com 60 a 90 dias de vida, foram contidos fisicamente para realização do teste lacrimal do vermelho de fenol (TLVF), da ponta de papel absorvente estĂ©ril e do teste lacrimal de Schirmer modificado (TLSm). O TLVF foi o mais difĂcil de ser executado devido Ă maleabilidade do fio, enquanto a TEPA se mostrou mais exequĂvel para ambas as espĂ©cies. A mediana ± intervalo semi-interquartil para o TLVF foi de 19,79±2,61mm/15” e 5,22±2,92mm/15”, para a TEPA foram de 16,25±1,82mm/min e 10,93±3,04mm/min, e para o TLSm foram de 0±1,63mm/min e 0±1,63mm/min, para gambás-de-orelha-branca e gambás-de-orelha-preta, respectivamente. NĂŁo houve diferença entre o olho direito e esquerdo e nem quanto ao sexo. Obteve-se diferença significativa para um mesmo teste entre as espĂ©cies. NĂŁo foi encontrada correlação significativa entre os testes para ambas as espĂ©cies. A quantificação da porção aquosa da lágrima poderá auxiliar no diagnĂłstico precoce de doenças oculares nas espĂ©cies estudadas.The establishment of parameters for tear production in different species is important for better understanding eye´s health and is one of the components of the ophthalmic semiological technique. Particularities derived from the anatomophysiology of non-domestic species induce the search for more reliable methodologies. The aim was to evaluate and compare tear production of white-eared opossum (Didelphis albiventris) and Brazilian common opossum (Didelphis aurita) by three different methods. Fifteen individuals of each species, juveniles, healthy, of both sexes, with 60 to 90 days of life, were physically restrained. Phenol red thread test (PRTT), endodontic absorbent paper point tear test (EAPPTT) and modified -Schirmer tear test (mSTT) were performed. PRTT was the most difficult to perform because of the wire malleability, while EAPPTT was more feasible for both species. The median ± semi-quartile range for PRTT were 19.79±2.61mm/15 “and 5.22±2.92mm/15”, for EAPPTT were 16.25±1.82mm/min and 10.9±3.04mm/min, and for STTm were 0±1.63mm/min and 0±1.63mm/min for white-eared opossum and Brazilian common opossum respectively. There was no difference between the right and left eye neither sex. A significant difference was obtained for the same test to different species. No significant correlation was found between the tests for both species. The description of tear production parameters for juvenile white-eared opossum and Brazilian common opossum may be used as a tool, which will allow the early diagnosis of ocular diseases
Selective Reflection Spectroscopy on the UV Third Resonance Line of Cs : Simultaneous Probing of a van der Waals Atom-Surface Interaction Sensitive to Far IR Couplings and of Interatomic Collisions
We report on the analysis of FM selective reflection experiments on the
6S1/2->8P3/2 transition of Cs at 388 nm, and on the measurement of the surface
van der Waals interaction exerted by a sapphire interface on Cs(8P3/2). Various
improvements in the systematic fitting of the experiments have permitted to
supersede the major difficulty of a severe overlap of the hyperfine components,
originating on the one hand in a relatively small natural structure, and on the
other hand on a large pressure broadening imposed by the high atomic density
needed for the observation of selective reflection on a weak transition. The
strength of the van der Waals surface interaction is evaluated to be 7310
kHz.m3. An evaluation of the pressure shift of the transition is also
provided as a by-product of the measurement. We finally discuss the
significance of an apparent disagreement between the experimental measurement
of the surface interaction, and the theoretical value calculated for an
electromagnetic vacuum at a null temperature. The possible influence of the
thermal excitation of the surface is evoked, because, the dominant
contributions to the vW interaction for Cs(8P3/2) lie in the far infrared
range.Comment: submitted to Laser Physics - issue in the memory of Herbert Walther
Modeling, Simulation and Control of Pedestrian Avoidance Maneuver for an Urban Electric Vehicle
In this paper, the mathematical model of an electric vehicle, as well as the control system for avoiding pedestrians in urban traffic is described. The vehicle is modeled as a continuous system consisting of several subsystems. The discrete model of several sensors and actuators, a decision system, and low-level controllers for acceleration/braking and steering systems are added. Based on this model, a pedestrian avoidance maneuver for typical speeds in city traffic is simulated. When the sensory system detects a pedestrian in the vehicle’s path, the decision system calculates its trajectory. Using this information, the speed and/or direction that the vehicle must take in order to avoid the accident are estimated. These values are sent to the low-level controllers of the accelerator/brake and steering, which generate the signals to be applied to such systems to achieve the desired trajectory and speed
Influence of Reoperations on Long-Term Quality of Life After Restrictive Procedures: A Prospective Study
Quality of life improves after bariatric surgery. However, long-term results and the influence of reoperations are not well known. A prospective quality of life assessment before, 1 and 7 years after laparoscopic adjustable gastric banding (LAGB) and vertical banded gastroplasty (VBG) was performed in order to determine the influence of reoperations during follow-up. One hundred patients were included in the study. Fifty patients underwent VBG and 50 LAGB. Patients completed the quality of life questionnaires prior to surgery and two times during follow-up. Health-related quality of life (HRQoL) questionnaires included the Nottingham Health Profile I and II and the Sickness Impact Profile 68. Follow-up was 84% with a mean duration of 84 months (7 years). During follow-up, 65% of VBG patients underwent conversion to Roux-en-Y gastric bypass while 44% of LAGB patients underwent a reoperation or conversion. One year after the procedure, nearly all quality-of-life parameters significantly improved. After 7 years, the Nottingham Health Profile (NHP)-I domain “physical ability”, the NHP-II and the SIP-68 domains “mobility control”, “social behavior”, and “mobility range” were still significantly improved in both groups. The domains “emotional reaction”, “social isolation” (NHP-I), and “emotional stability” (SIP-68) remained significantly improved in the VBG group while this was true for the domain “energy level” (NHP-I) in the LAGB group. Both the type of procedure and reoperations during follow-up were not of significant influence on the HRQoL results. Weight loss and decrease in comorbidities were the only significant factors influencing quality of life. Restrictive bariatric surgery improves quality of life. Although results are most impressive 1 year after surgery, the improvement remains significant after long-term follow-up. Postoperative quality of life is mainly dependent on weight loss and decrease in comorbidities and not on the type of procedure or surgical complications
CĂłmo y cuándo derivar un paciente con cefalea secundaria y otros tipos de dolores craneofaciales desde Urgencias y AtenciĂłn Primaria: recomendaciones del Grupo de Estudio de Cefaleas de la Sociedad Española de NeurologĂa
IntroducciĂłn: Cuando se sospecha que estamos ante una cefalea secundaria y se deriva un paciente a Urgencias o a la consulta de NeurologĂa es importante saber quĂ© exploraciones complementarias son oportunas hacer en cada caso, además de saber posteriormente cuál es el circuito adecuado que ha de seguir el paciente. Por este motivo, el Grupo de Estudio de Cefaleas de la Sociedad Española de NeurologĂa (GECSEN) ha decidido crear unas recomendaciones consensuadas que establezcan un protocolo de derivaciĂłn de pacientes con cefalea y/o neuralgias craneofaciales.
Desarrollo: Se ha contactado con neurĂłlogos jĂłvenes con interĂ©s y experiencia en cefalea y con la Junta Directiva del GECSEN han desarrollado este documento que, por razones prácticas, se ha dividido en 2 artĂculos. El primero centrado en las cefaleas primarias y neuralgias craneofaciales, y este centrado en las cefaleas secundarias y otros dolores craneofaciales. El enfoque es práctico, con tablas que resumen los criterios de derivaciĂłn con exploraciones complementarias y otros especialistas a los que derivar, para que sea Ăştil y facilite su uso en nuestra práctica asistencial diaria.
Conclusiones: Esperamos ofrecer una guĂa y herramientas para mejorar la toma de decisiones ante un paciente con cefalea valorando exploraciones a priorizar y que circuitos seguir para asĂ evitarla duplicaciĂłn de consultas y retrasos en el diagnĂłstico y en el tratamiento
Optimised Motion Tracking for Positron Emission Tomography Studies of Brain Function in Awake Rats
Positron emission tomography (PET) is a non-invasive molecular imaging technique using positron-emitting radioisotopes to study functional processes within the body. High resolution PET scanners designed for imaging rodents and non-human primates are now commonplace in preclinical research. Brain imaging in this context, with motion compensation, can potentially enhance the usefulness of PET by avoiding confounds due to anaesthetic drugs and enabling freely moving animals to be imaged during normal and evoked behaviours. Due to the frequent and rapid motion exhibited by alert, awake animals, optimal motion correction requires frequently sampled pose information and precise synchronisation of these data with events in the PET coincidence data stream. Motion measurements should also be as accurate as possible to avoid degrading the excellent spatial resolution provided by state-of-the-art scanners. Here we describe and validate methods for optimised motion tracking suited to the correction of motion in awake rats. A hardware based synchronisation approach is used to achieve temporal alignment of tracker and scanner data to within 10 ms. We explored the impact of motion tracker synchronisation error, pose sampling rate, rate of motion, and marker size on motion correction accuracy. With accurate synchronisation (<100 ms error), a sampling rate of >20 Hz, and a small head marker suitable for awake animal studies, excellent motion correction results were obtained in phantom studies with a variety of continuous motion patterns, including realistic rat motion (<5% bias in mean concentration). Feasibility of the approach was also demonstrated in an awake rat study. We conclude that motion tracking parameters needed for effective motion correction in preclinical brain imaging of awake rats are achievable in the laboratory setting. This could broaden the scope of animal experiments currently possible with PET
- …