12,559 research outputs found
A new dual-beam technique for precise measurements of spectral reflectance in the field
No full textField spectral measurements made using the single - beam method often include errors due to variation in illumination between measurement of the target and the
reference (panel or cosine -corrected receptor). Although the dual-beam method avoids these errors, it introduces greater complexity due to the need to intercalibrate the two sensor heads used, and it is significantly more expensive. This paper describes an alternative dual-beam method which uses a neural network to estimate the complete irradiance spectrum from measurements made in 7 narrow bands. These narrow band measurements of irradiance may be made with a simple
filter-based radiometer, thus avoiding the expense and complexity of a second spectroradiometer. The new technique has been tested using irradiance spectra from both continental and maritime locations
Antenatal umbilical Doppler abnormalities: an independent risk factor for early onset neonatal necrotizing enterocolitis in premature infants
No full textBackground: necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) emergency seen in neonatal units. Many factors have been considered as potentially important aetiologically, including gut ischaemia, sepsis and feeding. However, evidence remains equivocal. Objective: this study investigated whether preterm babies born to mothers with abnormal antenatal umbilical Dopplers (absent or reversed end diastolic flow - AREDF), that is exposed to antenatal gut ischaemia, are at an identical risk of developing NEC early in life, compared to babies born to mothers with normal Dopplers. Methods: all preterm (≤32 + 6 week gestation) babies with no congenital anomaly, born to mothers resident in the county of Leicestershire in United Kingdom in 2001 and 2002 were identified using the Trent Neonatal Survey (TNS). Clinical data including the presence and severity of any NEC were extracted from the notes. Results: two hundred forty-three preterm babies who met the criteria were identified during the period. Babies in whom umbilical Dopplers were not available and babies that died in the first 48 h were excluded. Complete data was thus available for 206 of these babies. A strong relation between AREDF and subsequent development of NEC was noted in these babies (OR: 5.88, 95% CI: 2.41 to 14.34, p < 0.0001). This association still held after adjustment for gestational age at birth (OR: 7.64, 95% CI: 2.96 to 19.70, p < 0.0001) and after adjustment for birthweight for gestational age z-score (OR: 6.72, 95% CI: 2.23 to 20.25, p = 0.0007). Conclusions: this study, based on a neonatal cohort, indicates that AREDF is an important independent risk factor for the production of NEC.</p
A novel scene-recording spectroradiometer
No full textIn this paper we describe an innovative approach to providing both a
synthesised dual-beam capability and a permanent photographic record of the
precise area sensed by a spectroradiometer. These advances have been achieved
without modifying the spectroradiometer and may be used with a wide range of
commercially-available spectroradiometers
Implementation of boundary conditions for optimized high-order compact schemes
No full textThe optimized high-order compact (OHOC) finite difference schemes, proposed as central schemes are used for aeroacoustic computations on interior nodes. On near-boundary nodes, accurate non-central or one-sided compact schemes are formulated and developed in this paper for general computations in domains with non-periodic boundaries. The near-boundary non-central compact schemes are optimized in the wavenumber domain by using Fourier error analysis. Analytic optimization methods are devised to minimize the dispersion and dissipation errors, and to obtain maximum resolution characteristics of the near-boundary compact schemes. With the accurate near-boundary schemes, the feasibility of implementing physical boundary conditions for the OHOC schemes are investigated to provide high-quality wave solutions. Characteristics-based boundary conditions and the free-field impedance conditions are used as the physical boundary conditions for direct computations of linear and nonlinear wave propagation and radiation. It is shown that the OHOC schemes present accurate wave solutions by using the optimized near-boundary compact schemes and the physical boundary condition
European Union Acts project MIDAS: objectives and progress to date
No full textIntroduction to the ACTS program: Advanced Communications and Technology and Services, known simply as ACTS, is one of the specific programmes of the "Fourth Framework Programme of European Community activities in the field of research and technological development and demonstration (1994-1998)". It provides the main focus of the European Unions research effort to accelerate deployment of advanced communications infrastructures and services, and is complemented by extensive European research in the areas of information technology and telematics. The stated objectives of ACTS are to "develop advanced communication systems and services for economic development and social cohesion within Europe, taking account of the rapid evolution of technologies, the changing regulatory situation and opportunities for development of advanced transeuropean networks and services". Within ACTS, the emphasis of the work has shifted from the exploration of fundamental concepts and detailed system engineering, as it had been in earlier programs such as RACE (Research and development in Advanced Communication technologies for Europe), to issues relating to implementation of advanced systems and generic services, and applications which demonstrate the potential use of advanced communications in Europe. A key feature of the ACTS program is that the research be undertaken in the context of real-world trials. Work within the program is divided into six technical areas: Interactive digital multimedia services, photonic technologies, high speed networking, mobility and personal communication networks, intelligence in networks and services and quality, safety and security of communication systems and services. The total EU budget for the ACTS program is approximately 670 MECU, covering around 160 projects, with over 1000 individual organisations participating within the program, thereby illustrating the scale of the activities. MIDAS is one of five projects in the technical area of photonic technologies concerned with high speed transmission, the others being ESTHER, UPGRADE, HIGHWAY and SPEED, each concerned with various aspects or approaches to the development of 40 GBit/s transmission systems within the European arena. A full list of project descriptions and objectives, as well as those of the ACTS program as a whole, are to be found in Ref [1]. The MIDAS consortium consists of the following organisations: Chalmers University of Technology (Sweden), CSELT (Italy), Thomson LCR (France), United Monolithic Semiconductor (France), Telia (Sweden), Kings College London (UK), University of Athens (Greece), ORC University of Southampton (UK). The project started in September 1995 and is currently scheduled to finish in September 1998
Carter, D.J. & Hargreaves, B. — A Field Guide to Caterpillars of Butterflies and Moths of Britain and Europe. Collins, London, 1986
No full textBourlière François. Carter, D.J. & Hargreaves, B. — A Field Guide to Caterpillars of Butterflies and Moths of Britain and Europe. Collins, London, 1986. In: Revue d'Écologie (La Terre et La Vie), tome 43, n°1, 1988. p. 98
Developing holey fibers for evanescent field devices
No full textThe overlap of the optical mode in a HF with the air holes is calculated for the first time. This is done using a vector modal decomposition approach. We show that a significant fraction of the modal power can be made to overlap with the holes, which suggests that these unusual fibres may be useful as evanescent field devices
Rapporteur’s report – innovative geotechnologies for energy transition
No full textThe 9th Society for Underwater Technology (SUT) International Conference on Offshore Site Investigation and Geotechnics (OSIG) closed with a Rapporteur’s report given by the author. This paper provides a record of that report, transcribed from a video recording. The presentation slides are shown as Figures.</p
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