Spatial resolution

Synchrotron radiation sources have proven to be highly beneficial in many fields of research for the characterization of materials. However, only a very limited proportion of studies have been conducted by the forensic science community. This is an area in which the analytical benefits provided by synchrotron sources could prove to be very important. This review summarises the applications found for synchrotron radiation in a forensic trace evidence context as well as other areas of research that strive for similar analytical scrutiny and/or are applied to similar sample materials. The benefits of synchrotron radiation are discussed in relation to common infrared, X-ray fluorescence, tomographic and briefly, X-ray diffraction and scattering techniques. In addition, X-ray absorption fine structure analysis (incorporating XANES and EXAFS) is highlighted as an area in which significant contributions into the characterization of materials can be obtained. The implications of increased spatial resolution on microheterogeneity are also considered and discussed.

Annual sequences of the first reprocessed albedo, bidirectional reflectance distribution function (BRDF), and nadir BRDF-adjusted surface reflectance (NBAR) products are being evaluated. BRDF model parameters (or weights) are used to compute black sky albedo at local solar noon and white sky albedo and to compute surface reflectance at a common nadir geometry. In addition to these standard resolution albedo, BRDF, and NBAR products, which are provided in the integerized sinusoidal grid projection, the BRDF parameters, black sky albedos (at local solar noon), and white sky albedos are now also being operationally produced in a global geographic projection known as the Climate Modeling Grid (CMG). These are currently available at a 0.25 degree spatial resolution, although there is community interest in a 0.05 degree resolution. In addition to the operational CMGs, coarser 0.5 degree and 1 degree resolution versions of the reprocessed albedo data have also been produced for the ISLSCP-II initiative. The global distribution of these albedos (as they vary throughout the year) are presented, as well as discussions of the most recent evaluations of the quality of the standard products.

Digital image correlation (DIC) is assessed as a tool for measuring strains with high spatial resolution in woven-fiber ceramic matrix composites. Using results of mechanical tests on aluminum alloy specimens in various geometric configurations, guidelines are provided for selecting DIC test parameters to maximize the extent of correlation and to minimize errors in displacements and strains. The latter error is shown to be exacerbated by the presence of strain gradients. In a case study, the resulting guidelines are applied to the measurement of strain fields in a SiC/SiC composite comprising 2-D woven fiber. Sub-fiber tow resolution of strain and low strain error are achieved. The fiber weave architecture is seen to exert a significant influence over strain heterogeneity within the composite. Moreover, strain concentrations at tow crossovers lead to the formation of macroscopic cracks in adjacent longitudinal tows. Such cracks initially grow stably, subject to increasing app lied stress, but ultimately lead to composite rupture. Once cracking is evident, the composite response is couched in terms of displacements, since the computed strains lack physical meaning in the vicinity of cracks. DIC is used to identify the locations of these cracks (via displacement discontinuities) and to measure the crack opening displacement profiles as a function of applied stress.

This paper summarizes several flow measurement systems qualified in the operation of different lead-bismuth loops in the KArslruhe Liquid Metal LAboratory (KALLA) during the last 5 years. There are several experimental techniques which were well proven in air and water and thus could be transferred similarly to liquid metals: these techniques are split into measuring local quantities as temperature, pressure e.g. by means of pressure taps or velocities using Pitot and Prandtl tubes or the Ultrasound Doppler velocimetry (UDV) for local flow velocities, as well as an integral quantity like the flow rate. Since the knowledge of the flow rate acts in terms of the operational safety of nuclear liquid metal systems as one of the most crucial parameters, this aspect is discussed widely herein. Unfortunately, as liquid metals are opaque, an optical access is not possible. Instead, one can take advantage of the high electric conductivity of liquid metals to measure integral and local quantities, like electromagnetic flow meters and miniaturised permanent magnetic probes for local velocity measurements. In this context especially the electromagnetic frequency flow meter (EMFM) is discussed as a prospective and reliable option to measure the flow rate without demanding extensive precognitions with respect to the fluid-wall interface behaviour. This article describes some of the techniques used in KALLA for different liquid metals, explains the measurement principle and shows some of the typical results obtained using these techniques. Also the measurement accuracy as well as the temporal and spatial resolution of each device is discussed and typical error sources to be expected are illuminated. Moreover, some hints for a correct placement of the individual sensor in the liquid metal environment are given.

The spatial resolution of numerical weather prediction and climate models is generally determined by their grid spacing (∆x) or spectral truncation and the numerical implementation of dynamical core and model parametrisations. For example features of the scale 2∆x and 3∆x are smoothed to avoid numerical instabilities (e.g., aliasing effects) and parameterisations in connection to advection, pressure gradient force, and subgrid-scale diffusion can only be well represented at dimensions of at least four times the grid spacing. Some parametrisations, however, generate energy at the grid-spacing scale. These multiple effects on the effective resolution of models are investigated in this study for three high resolution regional climate models (RCMs) in dependence of their grid spacing.

A new, molybdenum core, 125 I interstitial brachytherapy seed is marketed by Bebig GmbH (IsoSeed s I25.S17) and our group has performed its Dosimetric characterization using Monte Carlo (MC) simulation and Thermoluminescence dosimetry (TLD) as recommended by the AAPM TG-43U1 prior to the clinical implementation of new low-energy seeds. This work presents the results of a supplementary experimental dosimetry study performed using PABIG polymer gel and Magnetic Resonance Imaging (MRI). One new I25.S17 seed and a commercially available, gold core, Bebig IsoSeed s I25.S06 125 I seed were positioned at two different locations in a vial filled with water equivalent, PABIG-polymer gel. The gel with the sources in place was MR scanned in 3D at various time intervals after seed placement using a time efficient, 3D, dual echo Turbo Spin Echo pulse sequence. The consensus dosimetry parameters published in the TG-43U1 for the I25.S06 seed were used to derive the gel response calibration curve for each scanning session. The calibration data were then used to provide dosimetry results for the new I25.S17 seed. Experimental results for the new seed in the form of dose distributions as well as dosimetric quantities in the prevalent TG-43 dosimetric formalism were found to be in close agreement with corresponding MC and TLD results. This finding suggests that the polymer gel-MRI method could at least play a supplementary role to TLD dosimetry in the dose characterization of low energy/low dose rate brachytherapy sources, especially in view of its potential for measurements with a fine spatial resolution down to short distances which are inhibitory to conventional experimental techniques.

A radio heliograph operating in the frequency range of 1200–1700 MHz is planned by INPE, Brazil, for investigations of time evolution of active regions, which will lead to better understanding of the physics of the flares energy release and particle acceleration, in order to suggest better criteria for the prediction of solar flares, Coronal Mass Ejections (CME), and solar terrestrial relations, such as geomagnetic storms and radio blackouts. In the first phase, the Brazilian Decimetric Array (BDA) will be a T shaped array 256 m by 144 m, consisting of 26 parabolic dish antennas of 4 m diameter. This array will produce full disk images of the sun with a spatial resolution of 3 by 5 arc minutes at 1420 MHz with a time resolution of 100 ms and sensitivity of ∼ 10 Jy. In the second phase, in addition to the compact T array there will be 6 more 7 m diameter antennas on an East-West baseline of 2560 m to obtain higher spatial resolution and better sensitivity. Thus, finally this radioheliograph will have wide field of view and couple of arcsec spatial resolution and high time resolution (100 ms).

An hybrid atomic force-scanning near-field optical microscope (AFM-SNOM) has been realized starting from a home-built AFM. The instrument uses a tetrahedral SiN tip for force and near field detection and is designed to provide, besides simple imaging, a full three-dimensional (3-D) mapping of force, friction and light intensity on the sample. High-resolution optical images of dielectric samples are presented together with curves describing the behavior of the collected optical intensity as a function of tip-object distance. AFM images and forcedistance curves are reported as well and are compared with those obtained from the optical channel. Subwavelength features of the samples can be easily appreciated in both kinds of images, and the refractive index of the object can be computed from the attenuation constant of the tunneling light detected by the tip, with the AFM curve providing a convenient way of detecting the contact point. The spatial resolution of this kind of measurement is far better than that obtainable with any other index-measuring device. Homogeneous glass samples as well as monomode channel waveguides were analyzed in our experiments. The refractive index of several different prisms, made either of BK7 (n = 1:519 at = 532 nm) or of SF58 (n = 1:932) glass, could be measured with our near-field technique. As for the channel waveguides, the accuracy of our measurements lets us detect their presence and lateral extension in the substrate but is not yet sufficient to allow the reconstruction of their index profile.

Using scintillation crystal sheets instead of discrete crystal arrays in high-resolution PET has the immediate advantage of reduced complexity as well as a potential for increased sensitivity. In order to evaluate the positioning capability of a position sensitive avalanche photodioide (PSAPD) using a sheet Lutetium Oxyorthosilicate (LSO) crystal scintillator, we studied the dependence of detected event position versus the known source position. In particular, we studied positioning in a continuous 8 mm 8 mm LSO sheet coupled to a PSAPD with an 8 mm 8 mm active area experimentally, studied optical transport in the sheet crystal with Monte Carlo simulation, and used two positioning methods to evaluate PSAPD pincushioning effects. Both collimated 57 Co 122 keV and coincidence-triggered 22 Na 511 keV sources were used in the experiments performed. We analyze the energy resolution, sensitivity, photopeak position and spatial resolution as a function of source position. An average point spread function (PSF) resolution of 2.86 and 1.12 mm FWHM for 57 Co and 22 Na respectively was observed. Within 1.2 mm from the edge of the LSO sheet, the average photopeak position change was 5%. Simulations using annihilation photon interactions from GATE and scintillation photon transport from DETECT2000, as well as utilizing a pincushion-reduction posioning algorithm, have confirmed that the positioning and energy response observed experimently at the edge of the crystal is due to optical transport near those edges.

Typically data acquired through imaging techniques such as functional magnetic resonance imaging (fMRI), structural MRI (sMRI), and electroencephalography (EEG) are analyzed separately. Each modality records brain structure and function at different scales, and fusing information from such complementary modalities promises to provide additional insight into connectivity across brain networks and changes due to disease. Recently, a number of methods have been proposed for data integration and fusion of two brain imaging modalities. We propose a new data fusion scheme based on canonical correlation analysis that enables the detection of associations across multiple modalities. Our multimodal canonical correlation analysis (mCCA) scheme works at the feature level using multi-set CCA to determine inter-subject covariations across modalities. We apply mCCA to fMRI, sMRI, and EEG data collected from patients diagnosed with schizophrenia and healthy controls. Through data collected from an auditory oddball task, we show that the fusion of multiple modalities detects more specific associations as compared to fusion of two modalities.

Mediante el cifrado de fotoheliogramas tomados en la Estación de Montaña de Pamir (resolución espacial de 0.3"), con ancho de banda de 40 nm centrado en los 650 nm, se obtuvo una secuencia de imágenes estandarizadas para el estudio dinámico de detalles de la umbra y la penumbra de la mancha principal del grupo. Se presentan los elementos básicos de la metodología de estandarización, así como los resultados morfológicos y fotométricos obtenidos. Si bien nuestras imágenes muestran, por simple inspección visual, la presencia de filamentos brillantes y oscuros en la penumbra, no se encontró un claro indicio de dos niveles fotométricos de brillo distintivos. Se determinó que el valor característico de la intensidad de la penumbra varía con el tiempo, lo que será investigado posteriormente. Se detectó la presencia de puntos y núcleos umbrales, analizándose su distribución espacial. Se determinó un valor característico del diámetro para los puntos umbrales.

Fiber tracking (FT) and quantification algorithms are approximations of reality due to limited spatial resolution, model assumptions, user-defined parameter settings, and physical imaging artifacts resulting from diffusion sequences. Until now, correctness, plausibility, ...

High Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction (SAED), Scanning Transmission Electron Microscopy with High-Angle Annular Dark-Field detector (HAADF-STEM), and Energy Dispersive X-ray Spectroscopy (EDXS) studies were performed in order to investigate the nanostructure, chemical composition and elemental distribution in depth of ZnO:Al thin films used as active channel layers of the thin films transistors (TFT) as well as at the interface with the Ti/Au metallization contacts. Energy Dispersive X-ray spectra (EDXS) and elemental maps acquired in the cross section of a TFT device evidenced the composition and the localization of atomic species and revealed the local chemistry at the nanometer scale rough interfaces.

By 2025, it is estimated that around 5 billion people, out of a total population of around 8 billion, will be living in countries experiencing water stress (using more than 20% of their available resources). Climate change has the potential to impose additional pressures in some regions. This paper describes an assessment of the implications of climate change for global hydrological regimes and water resources. It uses climate change scenarios developed from Hadley Centre climate simulations (HadCM2 and HadCM3), and simulates global river #ows at a spatial resolution of 0.5;0.53 using a macro-scale hydrological model. Changes in national water resources are calculated, including both internally generated runo! and upstream imports, and compared with national water use estimates developed for the United Nations Comprehensive Assessment of the Freshwater Resources of the World. Although there is variation between scenarios, the results suggest that average annual runo! will increase in high latitudes, in equatorial Africa and Asia, and southeast Asia, and will decrease in mid-latitudes and most subtropical regions. The HadCM3 scenario produces changes in runo! which are often similar to those from the HadCM2 scenarios * but there are important regional di!erences. The rise in temperature associated with climate change leads to a general reduction in the proportion of precipitation falling as snow, and a consequent reduction in many areas in the duration of snow cover. This has implications for the timing of stream#ow in such regions, with a shift from spring snow melt to winter runo!. Under the HadCM2 ensemble mean scenario, the number of people living in countries with water stress would increase by 53 million by 2025 (relative to those who would be a!ected in the absence of climate change). Under the HadCM3 scenario, the number of people living in countries with water stress would rise by 113 million. However, by 2050 there would be a net reduction in populations in stressed countries under HadCM2 (of around 69 million), but an increase of 56 million under HadCM3. The study also showed that di!erent indications of the impact of climate change on water resource stresses could be obtained using di!erent projections of future water use. The paper emphasises the large range between estimates of`impacta, and also discusses the problems associated with the scale of analysis and the de"nition of indices of water resource impact.

A wide variety of imaging applications exist for 1K x 1K midwave infrared (MWIR) imagers and Nova's Variable Acuity Superpixel Imager (VASTM) technology1,2 has now progressed to this image format. This paper will demonstrate a variety of imagery from MWIR cameras using this large format "LVASI" device; the in-pixel processing used by the LVASI cameras represents the state-of-the-art for image size, total field of view, high frame rates, low data bandwidths and real-time spatial reprogrammability of focal plane arrays (FPAs). Using these devices, imaging systems may now be implemented that permit the operator to "zoom in" to regions of interest with very high spatial resolution, while covering the remainder of the total field of view (TFOV) at conventional resolutions. The bandwidth compression attainable using these sensors helps to make possible systems that can transmit their high resolution imagery through wireless interconnected networks. We present recent infrared image data that highlight numerous applications including missile detection/tracking, search/rescue and remote surveillance applications.

The main purpose of this paper is to present the study of tra$c emissions impact on the Lisbon region air quality. Two approaches of emission data generation with high spatial and temporal resolution are presented and compared. Main roads were processed as line sources and hot on-road emissions were calculated based on daily mean tra$c and emission factors distinguished for several road classes and vehicle types. Also, the disaggregation of national CORINAIR inventory has been performed on the basis of statistical information of fuel consumption and population density. The comparison of emission data obtained by these two approaches demonstrates a good agreement for total values, but a signi"cant di!erence for spatial distribution of the data. To ensure completeness of the data, to improve their spatial resolution and also to analyse the impact of the tra$c emissions, a combination of the two approaches was applied to generate the emission data used by a photochemical numerical system to simulate the atmospheric circulation and the air pollution pattern in Lisbon under summer meteorological conditions, having di!erent emission scenarios. It was possible to conclude that an air pollution abatement strategy is urgently needed and it should take into account the strong contribution of road tra$c emissions to the Lisbon air pollution levels.

The home gateway integrates heterogeneous home network environments and interconnects the home network and the public access networks. It is natural that users want to see the visual contents on the home network from outside the home. However, there exist significant differences in network capability and computing power of users. Video transcoding technique is an efficient mechanism to deliver visual contents to a variety of users who have different network conditions or terminal devices with different display capabilities. In this paper, we propose an efficient video transcoding technique as the key component of the home gateway architecture. It consists of two types of transcoding methods for adapting the bitrate of streaming video to the bandwidth of the transmission channel; spatial resolution reduction transcoding and temporal resolution reduction transcoding. The two transcoding methods are alternatively or simultaneously operated according to the requirements of users. Experimental results show that the proposed transcoding methods can preserve image quality while transcoding to the low bitrate 1 .

Multi-Agent transport simulation models, e.g. MATSim have proven to be suitable for modeling microscopic demand for large scale scenarios based on planning networks. In the recent years survey methods are using technologies which provides mobility information with a much higher spatial resolution (e.g. GPS tracking). Therefore, the need to model travel demand on detailed navigation networks rises, which slows down simulation speed significantly. This paper presents methods to increase the performance of the micro simulation model of MATSim using event driven concepts as well as a parallel implementation. The performance experiments with navigation networks of Switzerland containing up to one million roads and 7.3 million agents clearly show that large-scale, multi-agent micro-simulation can also be applied on high resolution networks.

Patient motion during brain SPECT studies can c l e m resolution and introduce distortion. We have developed a correction method which incorporates a motion tracking system to monitor the position and orientation of the patient's head during acquisition. Correction is achieved by spatially repositioning projections according to measured head movements and reconstructing these projections with a fully three-dimensional (3D) algorithm. The method has been evaluated in SPECT studies of the Hoffman 3D brain phantom performed on a triple head camera with fan beam collimation. Movements were applied to the phantom and recorded by a head tracker during SPECT acquisition. Fully 3D reconstruction was performed using the motion data provided by the tracker. Correction accuracy was assessed by comparing the corrected and uncorrected studies with a motion free study, visually and by calculating mean squared error (MSE). In all studies, motion correction reduced distortion and improved MSE by a factor of 2 or more. We conclude that this method can compensate for head motion under clinical SPECT imaging conditions. 0-7803-5021 -9/99/$10.00 0 1999 IEEE.

We are investigating imaging techniques to study the tumor response to photodynamic therapy ͑PDT͒. Positron emission tomography ͑PET͒ can provide physiological and functional information. High-resolution magnetic resonance imaging ͑MRI͒ can provide anatomical and morphological changes. Image registration can combine MRI and PET images for improved tumor monitoring. In this study, we acquired high-resolution MRI and microPET 18 F-fluorodeoxyglucose ͑FDG͒ images from C3H mice with RIF-1 tumors that were treated with Pc 4-based PDT. We developed two registration methods for this application. For registration of the whole mouse body, we used an automatic three-dimensional, normalized mutual information algorithm. For tumor registration, we developed a finite element model ͑FEM͒-based deformable registration scheme. To assess the quality of whole body registration, we performed slice-by-slice review of both image volumes; manually segmented feature organs, such as the left and right kidneys and the bladder, in each slice; and computed the distance between corresponding centroids. Over 40 volume registration experiments were performed with MRI and microPET images. The distance between corresponding centroids of organs was 1.5± 0.4 mm which is about 2 pixels of microPET images. The mean volume overlap ratios for tumors were 94.7% and 86.3% for the deformable and rigid registration methods, respectively. Registration of high-resolution MRI and microPET images combines anatomical and functional information of the tumors and provides a useful tool for evaluating photodynamic therapy.

The CrIS and ATMS instruments on NPOESS will provide high quality temperature and moisture profiles greatly surpassing the capabilities of current operational satellite sounders. However, performance of these systems continues to be a challenge in cloudy scenes. The VIIRS sensor on NPOESS will provide much higher spatial resolution data than that of CrIS, with some overlap in spectral coverage. This sub-pixel information can be used to enhance the retrieval performance in a number of ways. This paper presents techniques to improve performance of the CrIS temperature profile retrievals by incorporating data from VIIRS. Improvements include more accurate retrievals in partly cloud situations, better effective spatial resolution and more robust quality control diagnostics. This paper will provide an overview of our approach and shows examples of its utility using data from the EOS-Aqua AIRS, AMSU and MODIS sensors.

The GPS radio occultation technique is a rather simple and inexpensive tool for profiling the electron density of the entire ionosphere from satellite orbit heights down to the bottomside. No other profiling technique (bottomside/topside vertical sounding, incoherent scatter) unifies profiling through the entire ionosphere with global coverage. First results of ionospheric radio occultation (IRO) measurements carried out on board the German CHAMP satellite are reported. To inform potential users we review IRO data products operationally generated in DLR/IKN Neustrelitz and distributed via the Information System and Data Center (ISDC) of GFZ. Methods and algorithms applied for product generation including their limitations in accuracy and spatial resolution are addressed. We present the status and results of product validation with independent data sources. The achieved accuracy of the retrieved electron density profiles is estimated in particular by comparing the IRO results with independent data obtained from vertical sounding stations on Earth and from the Langmuir probe on board CHAMP. It is concluded that CHAMP-IRO measurements have the potential to establish global data sets of electron density profiles for developing and improving global ionospheric models and to provide operational space weather information.

This paper describes an attempt to model soil moisture over the Australian continent with an integrated system of dynamic models and a Geographic Information System (GIS) data base. A land surface scheme with improved treatment of soil hydrological processes is described. The non-linear relationships between soil hydraulic conductivity, matric potential and soil moisture are derived from the Broadbridge and White soil model. For a single location, the prediction of the scheme is in good agreement with the measurements of the Hydrological and Atmospheric Pilot Experiment (HAPEX). High resolution atmospheric and geographic data are used in soil moisture prediction over the Australian continent. The importance of reliable land surface parameters is emphasized and details are given for deriving the parameters from a GIS. Predicted soil moisture patterns over the Australian continent in summer, with a 50 km spatial resolution, are found to be closely related to the distribution of soil types, apart from isolated areas and times under the influence of precipitation. This is consistent with the notion that the Australian continent in summer is generally under water stress. In contrast, predicted soil temperatures are more closely related to radiation patterns and changes in atmospheric circulation. The simulation can provide details of soil moisture evolution both in space and time, that are very useful for studies of land use sustainability, such as plant growth modelling and soil erosion prediction.

Intramyocellular lipid (IMCL) plays an important role in the study of metabolism in vivo. Magnetic resonance spectroscopy (MRS) studies of IMCL are usually performed with clinical 1.5-T magnetic resonance imaging (MRI) systems and have employed the single-voxel MRS technique. The present study reports the results of our systematic evaluation of the ability of single-and multi-voxel MRS to yield high-quality, contamination-free IMCL levels from the tibialis anterior (TA) muscle. A clinical, 1.5-T, whole-body MRI scanner was used to measure IMCL with a standard knee coil, head coil, or a 3-cm receive-only surface coil with a body coil transmit. Excellent IMCL spectra were obtained in healthy males in only 8 min from multiple 0.25-cm 3 voxels using the surface coil receive/body coil transmit in conjunction with the standard PRESS spectroscopic imaging (SI) technique. This approach provided the spatial resolution and voxel placement flexibility permitting optimal separation of IMCL and extramyocellular lipid. Our findings demonstrate the potential of the SI approach.

Profiles of currents, density, and microstructure were obtained in the Pacific Ocean on and near the equator at 140øW in late 1984 as pa• of the Tropic Heat program. During a 4•-day time series on the equator, the shear zone above the core of the undercurrent had very low mean Richardson numbers, Ri, between Va and «. Average turbulent dissipation rates, e, were high in this zone, = 10 -7 Wkg -1, and varied by a factor of 100 between minima in the early afternoon and maxima at night. The signal reached to 90 m, well into the stratified zone. Eddy coefficients, K, were low at high Ri, and gradually increased as Ri decreased, until they rose dramatically near Ri =Va. The observed K (Ri) relations are specific to time, location, and temporal and spatial resolution of the data.

Land-use change models are important tools for integrated environmental management. Through scenario analysis they can help to identify near-future critical locations in the face of environmental change. A dynamic, spatially explicit, land-use change model is presented for the regional scale: CLUE-S. The model is specifically developed for the analysis of land use in small regions (e.g., a watershed or province) at a fine spatial resolution. The model structure is based on systems theory to allow the integrated analysis of land-use change in relation to socio-economic and biophysical driving factors. The model explicitly addresses the hierarchical organization of land use systems, spatial connectivity between locations and stability. Stability is incorporated by a set of variables that define the relative elasticity of the actual land-use type to conversion. The user can specify these settings based on expert knowledge or survey data. Two applications of the model in the Philippines and Malaysia are used to illustrate the functioning of the model and its validation.

Purpose The aim of this study was to improve the uniformity of the axial spatial resolution and sensitivity in pinhole single-photon emission computed tomography (SPECT) and to extend the axial field of view, by using a dedicated three-pinhole collimator. Methods A rectangular tungsten plate with three pinhole apertures of 1.5 mm diameter was designed to image a cylindrical field of view of 55 mm diameter and 160 mm axial length using a clinical gamma camera. To evaluate the non-uniformity of spatial resolution and noise, a multiple-disk phantom was built. The phantom was filled with Tc-99m, and data were acquired using a circular orbit and reconstructed with a dedicated iterative reconstruction algorithm. The axial spatial resolution together with the noise was measured in each disk. These measurements were compared to a single-pinhole system using an identical acquisition geometry and reconstruction. Results At the central slice, a spatial resolution of 2.7 mm was observed for both the three-pinhole and single-pinhole geometries. At 17.5 mm from the central slice, the axial spatial resolution deteriorated to 10.3 mm when using a single pinhole, while the spatial resolution remained 2.7 mm for the three-pinhole system. In the central slice, 19% noise was observed for both geometries. At 31.5 mm from this central slice, the noise remained 19% for the three-pinhole geometry, while it increased to 32% using a single pinhole. Conclusion The presented three-pinhole collimator improves the uniformity of the axial spatial resolution and sensitivity in pinhole SPECT and consequently extends the axial field of view, a requirement for whole-body small-animal imaging.

A deterministic algorithm is proposed to simulate phase contrast (PC) X-ray images for complex three-dimensional (3D) objects. This algorithm has been implemented in a simulation code named VXI (virtual X-ray imaging). The physical model chosen to account for PC technique is based on the Fresnel-Kirchhoff diffraction theory.

Scenarios with daily time resolution are frequently used in research on the impacts of climate change. These are traditionally developed by regional climate models (RCMs). The spatial resolution, however, is usually too coarse for local climate change analysis, especially in regions with complex topography, such as Norway. The RCM used, HIRHAM, is run with lateral boundary forcing provided from two global medium resolution models; the ECHAM4/OPYC3 from MPI and the HadAM3H from the Hadley centre. The first is run with IPCC SRES emission scenario B2, the latter is run with IPCC SRES emission scenarios A2 and B2. All three scenarios represent the future time period 2071-2100. Both models have a control run, representing the present climate . Daily temperature scenarios are interpolated from HIRHAM to Norwegian temperature stations. The at-site HIRHAMtemperatures, both for the control and scenario runs, are adjusted to be locally representative. Mean monthly values and standard deviations based on daily values of the adjusted HIRHAM-temperatures, as well as the cumulative distribution curve of daily seasonal temperatures, are conclusive with observations for the control period. Residual kriging are used on the adjusted daily HIRHAMtemperatures to obtain high spatial temperature scenarios. Mean seasonal temperature grids are obtained. By adjusting the control runs and scenarios and improving the spatial resolution of the scenarios, the absolute temperature values are representative at a local scale. The scenarios indicate larger warming in winter than in summer in the Scandinavian regions. A marked west-east and south-north gra-dient is projected for Norway, where the largest increase is in eastern and northern regions. The temperature of the coldest winter days is projected to increase more than the warmer temperatures.

A new type of X-ray imaging crystal spectrometer for Doppler measurements of the radial profiles of the ion temperature and plasma rotation velocity in tokamak plasmas is presently being developed in a collaboration between various laboratories. The spectrometer will consist of a spherically bent crystal and a two-dimensional position sensitive detector; and it will record temporally and spatially resolved X-ray line spectra from highly-charged ions. The detector must satisfy challenging requirements with respect to count rate and spatial resolution. The paper presents the results from a recent test of a PILATUS II detector module on Alcator C-Mod, which demonstrate that the PILATUS II detector modules will satisfy these requirements.

This article describes a fiber-optic interrogation device based on the pulsed time-of-flight technique. The apparatus is capable of measuring time delays between wideband reflectors, such as connectors, along a fiber path with a precision of about 280 fs (rms value) and a spatial resolution of about 3 ns (0.30 m) in a measurement time of 25 ms. Potential application areas include measuring integral strain and its derivatives such as cracks, deflections, and displacements, particularly in large civil engineering and composite structures. The operation and basic blocks of the measurement system are presented in detail together with measurement results obtained in laboratory and field conditions. It is shown that by using a fiber loop sensor with a reference fiber, it is possible to achieve a strain precision below 1 microstrain and a measurement frequency of 4 Hz. System performance proved adequate for the study of both static and dynamic phenomena in a bridge deck.

INTRODUCTION The spatial resolution of magnetic resonance spectroscopic imaging (MRSI) is typically coarse (e.g., 1 cm^3 voxels), mainly due to SNR limitations. However, the increased signal available with higher field scanners and new array coils now permits higher spatial resolution than is feasible with conventional chemical shift imaging (phase encoding) within the time available in a clinical MRSI exam. More efficient data acquisition methods are required. The use of time varying gradients during the readout window is a well known method for reducing the scan time, with some of the spatial encoding done at the same time as the spectral readout [1]. While some of these methods are sensitive to conditions encountered in practice (timing errors, eddy currents etc.) or require a sophisticated data reconstruction, the "flyback" echo-planar trajectory [2] is particularly insensitive to errors and provides data that are simple to process. Recent advances in gradient hardware have made flyback trajectories feasible with the higher spatial resolutions and larger spectral bandwidth of high-field MRSI. In this abstract we present the design of flyback echo-planar trajectories that make full use of the gradient performance available with a modern, whole-body MRI system. THEORY The readout gradient for a flyback echo-planar trajectory consists of a flat section during which data are acquired, followed by a rewind lobe that retraces across the desired portion of k-space as quickly as possible. The most efficient form of such a gradient consists of rewind lobes using the maximum slew rate of the gradient hardware, interleaved with flat portions that exactly cover the desired extent in k-space. The duration (and thus amplitude) of this flat part is determined by the desired spectral bandwidth (SBW), with SBW = 1/(T_flat + T_rewind). Since data are not acquired during the rewind lobe of the flyback gradient, a penalty in SNR is incurred relative to the usual continuous sampling during the readout window. This penalty, expressed as the fraction of the full SNR that could be achieved during the same readout time, is given by SNRf = (T_flat/(T_flat + T_rewind))

The polysaccharide chitosan is a versatile scaffold for assembly and conjugation of biomolecules, including nucleic acids, proteins, and viruses. It provides unique value in bioMEMS in that it can be electrodeposited on demand at specific locations in closed microfluidic systems, enabling spatial and temporal programmability of biomolecular binding and reaction sites in bio-microfluidic networks. In anticipating the scaling of such systems to smaller dimensions, we have investigated the spatial resolution which the chitosan electrodeposition process can achieve, using micron-scale electrode patterns coupled with fluorescence and Raman microscopies to assess the fidelity and edge sharpness of the resulting chitosan patterns. These show that electrodeposited chitosan scaffolds can be defined to an edge sharpness of 0.5-1.0 mm, compatible with the vast majority of microfluidics and bioMEMS applications, where microfluidic channel dimensions in the range of 10s or 100s of micrometers are common.

Land cover class composition of image pixels can be estimated using soft classification techniques. However, their output provides no indication of how such classes are distributed spatially within the instantaneous field of view represented by the pixel. Robust techniques to provide an improved spatial representation of land cover have yet to be developed. The use of a Hopfield neural network technique to map the spatial distributions of classes reliably using information of pixel composition determined from soft classification was investigated in previous papers by Tatem et al. The network converges to a minimum of an energy function defined as a goal and several constraints. The approach involved designing the energy function to produce a 'best guess' prediction of the spatial distribution of class components in each pixel. Tatem et al described the application of the technique to target mapping at the sub-pixel scale, but only for single classes. We now show how this approach can be extended to map multiple classes at the sub-pixel scale, by adding new constraints into the energy formulation. The new technique has been applied to simulated SPOT HRV and Landsat TM agriculture imagery to derive accurate estimates of land cover. The results show that this extension of the neural network now represents a simple efficient tool for mapping land cover and can deliver requisite results for the analysis of practical remotely sensed imagery at the sub pixel scale.

Temperate zone deciduous tree phenology may be vulnerable to projected temperature change, and associated geographical impact is of concern to ecologists. Although many phenology models have been introduced to evaluate climate change impact, there has been little attempt to show the spatial variation across a geographical region due to contamination by the urban heat island (UHI) effect as well as the insufficient spatial resolution of temperature data. We present a practical method for assessing climate change impact on tree phenology at spatial scales sufficient to accommodate the UHI effect. A thermal time-based two-step phenological model was adapted to simulate and project flowering dates of Japanese cherry (Prunus serrulata var. spontanea) in South Korea under the changing climates. The model consists of two sequential periods: the rest period described by chilling requirements and the forcing period described by heating requirements. Daily maximum and minimum temperature are used to calculate daily chill units until a pre-determined chilling requirement for rest release is met. After the projected rest release date, daily heat units (growing degree days) are accumulated until a pre-determined heating requirement for flowering is achieved. Model parameters were derived from the observed bud-burst and flowering dates of cherry tree at the Seoul station of the Korea Meteorological Administration (KMA), along with daily temperature data for 1923-1948. The model was validated using the observed data at 18 locations across South Korea during 1955-2004 with a root mean square error of 5.1 days. This model was used to project flowering dates of Japanese cherry in South Korea from 1941 to 2100. Gridded data sets of daily maximum and minimum temperature with a 270 m grid spacing were prepared for the climatological normal years

A new high-resolution recording device for transmission electron microscopy (TEM) is urgently needed. Neither film nor CCD cameras are systems that allow for efficient 3-D high-resolution particle reconstruction. We tested an active pixel sensor (APS) array as a replacement device at 200, 300, and 400 keV using a JEOL JEM-2000 FX II and a JEM-4000 EX electron microscope. For this experiment, we used an APS prototype with an area of 64  64 pixels of 20 mm  20 mm pixel pitch. Single-electron events were measured by using very low beam intensity. The histogram of the incident electron energy deposited in the sensor shows a Landau distribution at low energies, as well as unexpected events at higher absorbed energies. After careful study, we concluded that backscattering in the silicon substrate and reentering the sensitive epitaxial layer a second time with much lower speed caused the unexpected events. Exhaustive simulation experiments confirmed the existence of these back-scattered electrons. For the APS to be usable, the backscattered electron events must be eliminated, perhaps by thinning the substrate to less than 30 mm. By using experimental data taken with an APS chip with a standard silicon substrate (300 mm) and adjusting the results to take into account the effect of a thinned silicon substrate (30 mm), we found an estimate of the signal-to-noise ratio for a back-thinned detector in the energy range of 200-400 keV was about 10:1 and an estimate for the spatial resolution was about 10 mm. r

Touch (or tactile) sensors are gaining renewed interest as the level of sophistication in the application of minimum invasive surgery and humanoid robots increases. The spatial resolution of current large-area (greater than 1 cm 2 ) tactile sensor lags by more than an order of magnitude compared with the human finger. By using metal and semiconducting nanoparticles, a ∼100-nm-thick, large-area thin-film device is self-assembled such that the change in current density through the film and the electroluminescent light intensity are linearly proportional to the local stress. A stress image is obtained by pressing a copper grid and a United States 1-cent coin on the device and focusing the resulting electroluminescent light directly on the charge-coupled device. Both the lateral and height resolution of texture are comparable to the human finger at similar stress levels of ∼10 kilopascals.

We reportfor thefirsttimeon theperformanceof theSLD Central Drift Chamber (CDC) at SLC, which has been recordingdatasince 1992. The low mass of the chamber and the use-of a gas characterized by both a low drift velocity and low diffusion constant help to minimize the drift-distance measurement errors. We describe some of the calibrations and corrections applied to the dam, and report on the resolutions achlevd tius far. We measure an intrinsic drift resolution of 55-110 pm in the region of uniform fiefd. " Analysis of the full drift-pulse waveform allows for efficient double-hit resolution of about 1 mm. Momentum resolution is characterized by the formula (dp~pt2)~0.00502+ (0.010/pt)2. Used in conjunction with the SLD vertex det~tor, the CDC permits measurements of impact parameters of high-momentum tracks to the level of 10 pm in the r-~plane and 36~m in the r-z plane. A resolution of 6.4% is achieved in the measurement of dE/dx for the electrons "inBhabha scattering events.

A Geographical Information System (GIS) based methodology has been used to construct the black carbon (BC) emission inventory for the Indian geographical region. The distribution of emissions from a broader level to a spatial resolution of 1°Â 1°grid has been carried out by considering micro level details and activity data of fossil fuels and bio-fuels. Our calculated total BC emissions were 1343.78 Gg and 835.50 Gg for the base years 2001 and 1991 respectively with a decadal growth of around 61%, which is highly significant. The district level analysis shows a diverse spatial distribution with the top 10% emitting districts contributing nearly 50% of total BC emission. Coal contributes more than 50% of total BC emission. All the metropolitan cities show high BC emissions due to high population density giving rise to high vehicular emissions and more demand of energy.

Adaptive space-frequency quantization scheme in scalar fashion applied to wavelet-based compression is presented. Because of strong demands due to detail preserving in lossy image archiving and transmission, as it is for example in medical applications, different modifications of uniform threshold quantization are considered. The main features of elaborated procedure are as follows: fitting threshold value to local data characteristics in backward way and quantization step size estimation for each subband as forward and backward framework in optimization procedure. Many tests conducted in real wavelet compression scheme c o n f i i significant efficiency of presented quantization procedures. Achieved total compression effectiveness is promising in spite of simple coding algorithm.

10 High-Dynamic Range Imaging for Dynamic Scenes Celine Loscos and Katrien Jacobs 10.1 Introduction................................................................ 259 10.2 High-Dynamic Range Images: Definition.................................... 261 10.3 HDR Image Creation from Multiple Exposures........ ...

Austenitic stainless steels (hereafter A-STS) such as STS304 and STS316 are paramagnetic metals. However, a small amount of partial magnetization is generated in A-STS because of the imperfect final heat treatment and mechanical processing. Surface cracks on paramagnetic metal with a partially magnetized region (hereafter PMR) are difficult to inspect. In this paper, we propose a method for high speed inspection and evaluation of a crack on A-STS. Cracks can be inspected with high speed by using 64 arrayed Hall sensors (HSA) with 3.5 mm spatial resolution and a sheet type induced current (STIC). Then, a crack can be evaluated quantitatively by using the detailed distribution of the magnetic field obtained by using single Hall sensor scanning (SSS) around the inspected crack area. Several cracks on A-STS with partially magnetized areas were examined and the experimental formulas were derived.

High rates of coastal retreat characterise the weakly cemented Plio-Pleistocene rocks and sediments which form much of the cliffed coastline of East Anglia, southern North Sea. The accurate establishment of sediment losses from these cliffs has a regional significance as these sediments are important in maintaining beaches and nearshore bank systems and in feeding nearshore sediment transport pathways. However, the high spatial and temporal variability of cliff failure processes in such materials necessitates fine-scale integration of alongshore variations in cliff retreat over a series of well-established time periods to accurately define cliffline recession rates and sediment volume inputs to the nearshore system. This study applied the DSAS (Digital Shoreline Analysis System) within the GIS software package ArcMap to digitised, georeferenced positions of former shorelines, obtained from historic maps and aerial photographs (after 1992), for the sections of Benacre-Southwold and Dunwich-Minsmere on the Suffolk coast of East Anglia, UK; transects were cast every 10 m alongshore, producing very high spatial resolution upon which to assess shoreline retreat (over 1000 transects along 11 km of shoreline). Long-term (1883-2008) mean shoreline retreat rates varied between 2.3-3.5 m a-1 (Benacre-Southwold) and 0.9 m a-1 (Dunwich-Minsmere). For six cliffed subunits within these larger coastal sections, spatial variations in cliffline recession rates for shorter time intervals (at ca. 20-year intervals) within this longer (125 year) period were established. The combination of recession rates with photogrammetric methods of obtaining cliff top elevation at the same spatial resolution, available using aerial photographs and digital terrain models, along with cliff sediment composition, allowed the calculation of sediment volumetric inputs from cliff retreat in the period 1992-2008. Re-assessment of the magnitude and location of sediment inputs into the nearshore zone, their interaction with regional sediment transport and the growth of inshore bank systems, as well as the implications for contemporary and near-future coastal management strategies are discussed with reference to this section of the Suffolk coast. Temporal and spatial variations in recession rates and sediment release from soft rock cliffs,