High resolution satellite imagery orientation accuracy assessment by leave-one-out method: accuracy index selection and accuracy uncertainty

The Leave-one-out cross-validation (LOOCV) was recently applied to the evaluation of High Resolution Satellite Imagery orientation accuracy and it has proven to be an effective method alternative with respect to the most common Hold-out-validation (HOV), in which ground points are split into two sets, Ground Control Points used for the orientation model estimation and Check Points used for the model accuracy assessment. On the contrary, the LOOCV applied to HRSI implies the iterative application of the orientationmodel using all the known ground points as GCPs except one, different in each iteration, used as a CP. In every iteration the residual between imagery derived coordinates with respect to CP coordinates (prediction error of the model on CP coordinates) is calculated; the overall spatial accuracy achievable from the oriented image may be estimated by computing the usual RMSE or, better, a robust accuracy index like the mAD (median Absolute Deviation) of prediction errors on all the iterations. In this way it is possible to overcome some drawbacks of the HOV: LOOCVis a reliable and robustmethod, not dependent on a particular set of CPs and on possible outliers, and it allows us to use each known ground point both as a GCP and as a CP, capitalising all the available ground information. This is a crucial problem in current situations, when the number of GCPs to be collected must be reduced as much as possible for obvious budget problems. The fundamentalmatter to deal with was to assess howwell LOOCVindexes (mADand RMSE) are able to represent the overall accuracy, that is howmuch they are stable and close to the corresponding HOV RMSE assumed as reference. Anyway, in the first tests the indexes comparison was performed in a qualitative way, neglecting their uncertainty. In this work the analysis has been refined on the basis of Monte Carlo simulations, starting from the actual accuracy of ground points and images coordinates, estimating the desired accuracy indexes (e.g. mAD and RMSE) in several trials, computing their uncertainty (standard deviation) and accounting for them in the comparison. Tests were performed on a QuickBird Basic image implementing an ad hoc procedure within the SISAR software developed by the Geodesy and Geomatics Team at the Sapienza University of Rome. The LOOCV method with accuracy evaluated by mAD seemed promising and useful for practical case

Low-energy Selective Laser Trabeculoplasty Repeated Annually: Rationale for the COAST Trial

The recent Laser in Glaucoma and Ocular Hypertension Trial provided the evidentiary basis for a paradigm shift away from the historical medication-first approach to glaucoma--which has numerous limitations, the most important of which is poor adherence to therapy --and toward a laser-first approach. Now 20 years after its commercialization, selective laser trabeculoplasty (SLT) is routinely performed consistently with its initial description, with energy titrated to the appearance of fine, champagne-like cavitation bubbles. A recent data set suggested that lower energy SLT, applied as primary therapy and repeated annually irrespective of intraocular pressure--rather than pro re nata when its effect wanes and irrespective of intraocular pressure rises --yields longer medication-free survival than standard energy SLT repeated pro re nata. A new study--Clarifying the Optimal Application of SLT Therapy --has been initiated to explore this preliminary finding in a pair of consecutive randomized trials. Herein, we provide an evidence-based rationale for the use of low-energy SLT repeated annually as primary therapy for mild to moderate primary open-angle glaucoma or high-risk ocular hypertension

Testing goGPS low-cost RTK positioning with a web-based track log management system

Location-based online collaborative platforms are proving to be an effective and widely adopted solution for geospatial data collection, update and sharing. Popular collaborative projects like OpenStreetMap, Wikimapia and other services that collect and publish user-generated geographic contents have been fostered by the increasing availability of location-aware palmtop devices. These instruments include GPS-enabled mobile phones and low-cost GPS receivers, which are employed for quick field surveys at both professional and non-professional levels. Nevertheless, data collected with such devices are often not accurate enough to avoid heavy user intervention before using or sharing them. Providing tools for collecting and sharing accuracy-enhanced positioning data to a wide and diverse user base requires to integrate modern web technologies and online services with advanced satellite positioning techniques. A web-based prototype system for enhancing GPS tracks quality and managing track logs and points of interest (POI), originally developed using standard GPS devices, was tested by using goGPS software to apply kinematic relative positioning (RTK) with low-cost single-frequency receivers. The workflow consists of acquiring raw GPS measurements from the user receiver and from a network of permanent GPS stations, processing them by RTK positioning within goGPS Kalman filter algorithm, sending the accurate positioning data to the web-based system, performing further quality enhancements if needed, logging the data and displaying them. The whole system can work either in real-time or post-processing, the latter providing a solution to collect and publish enhanced location data without necessarily requiring mobile Internet connection on the field. Tests were performed in open areas and variously dense urban environments, comparing different indices for quality-based filtering. Results are promising and suggest that the integration of web technologies with advanced geodetic techniques applied to low-cost instruments can be an effective solution to collect, update and share accurate location data on collaborative platforms

Fluorescence suppression using micro-scale spatially offset Raman spectroscopy

We present a new concept of fluorescence suppression in Raman microscopy based on micro-spatially offset Raman spectroscopy which is applicable to thin stratified turbid (diffusely scattering) matrices permitting the retrieval of the Raman signals of sublayers below intensely fluorescing turbid over-layers. The method is demonstrated to yield good quality Raman spectra with dramatically suppressed fluorescence backgrounds enabling the retrieval of Raman sublayer signals even in situations where conventional Raman microscopy spectra are fully overwhelmed by intense fluorescence. The concept performance was studied theoretically using Monte Carlo simulations indicating the potential of up to an order or two of magnitude suppression of overlayer fluorescence backgrounds relative to the Raman sublayer signals. The technique applicability was conceptually demonstrated on layered samples involving paints, polymers and stones yielding fluorescence suppression factors between 12 to above 430. The technique has potential applications in a number of analytical areas including cultural heritage, archaeology, polymers, food, pharmaceutical, biological, biomedical, forensics and catalytic sciences and quality control in manufacture

Synchrotron radiation μ X-ray diffraction in transmission geometry for investigating the penetration depth of conservation treatments on cultural heritage stone materials

The assessment of the penetration depth of conservation treatments applied to cultural heritage stone materials is a burning issue in conservation science. Several analytical approaches have been proposed but, at present, many of them are not fully exhaustive to define in a direct way the composition and location of the conservation products formed after inorganic mineral treatments. Here, we explored, for the first time, the analytical capability of synchrotron radiation m X-ray diffraction in transmission geometry (SR-mTXRD) for the study of the crystal chemistry and penetration depth of the consolidating phases formed after the application of diammonium hydrogen phosphate (DAP) treatments on a porous carbonatic stone (Noto limestone). The SR-mTXRD approach provided unambiguous information on the nature of the newly formed calcium phosphates (hydroxyapatite, HAP, and octacalcium phosphate, OCP) with depth, supplying important indications of the diffusion mechanism and the reactivity of the substrate. Qualitative and semi-quantitative data were obtained at the microscale with a non-destructive protocol and an outstanding signal-to-noise ratio. The SR-mTXRD approach opens a new analytical scenario for the investigation of a wide range of cultural heritage materials, including natural and artificial stone materials, painted stratigraphies, metals, glasses and their decay products. Furthermore, it can potentially be used to characterize the penetration depth of a phase \u201cA\u201d (or more crystalline phases) in a matrix \u201cB\u201d also beyond the cultural heritage field, demonstrating the potential wide impact of the study

Scientific investigation to look into the conservation history of a Tang Dynasty terracotta Dancing Horse

AbstractA terracotta Dancing Horse sculpture dating to the Tang Dynasty (China) and owned by the Cincinnati Art Museum (US) is the topic of the present investigation. Besides its intrinsic artistic and historical values, the peculiarity of this horse concerns its conservation history; it shows extensive breakage signs and restoration and above all, the presence of an odd tassel on the frontal part of the head. Nine tassels are present on the two sides of the body, which is very common for these kinds of sculptures. Here, a scientific survey of this masterpiece is proposed aimed at looking into its conservation history, shedding light into the condition of the body and the tassels and the presence of residual conservation products applied during its troubled history. A comparative molecular, chemical and mineralogical study of the tassels is carried out focused on the identification of original and non-original materials, eventually added during restoration works. The multi-analytical protocol has been optimized for achieving as much information as possible from the available samples, a few mg of powders. X-ray powder diffraction and Raman Spectroscopy techniques have been followed by Fourier Transformed Infrared Spectroscopy and Ionic Chromatography, using the same small aliquot of powders. Scientific investigations highlighted that the odd tassel on the head and other two tassels on the body are not original, but replaced or added in subsequent time. Their composition includes both organic (polyester resin and/or phthalate) and inorganic compounds (sulphates and carbonates). Further data on original terracotta composition, decay substances and applied conservation products, provided new knowledge on past restoration treatments and cultural value. Importantly, the outcomes achieved with X-ray powder diffraction to identify the tassels authenticity were matched by Raman Spectroscopy, a technique that can be also used in situ with portable instruments, paving the way to non-invasive in situ authenticity studies as future perspective

Analytical capability of defocused μ-SORS in the chemical interrogation of thin turbid painted layers

© The Author(s) 2015. A recently developed micrometer-scale spatially offset Raman spectroscopy (m-SORS) method provides a new analytical capability for investigating non-destructively the chemical composition of sub-surface, micrometer-scale thickness, diffusely scattering layers at depths beyond the reach of conventional confocal Raman microscopy. Here, we demonstrate experimentally, for the first time, the capability of μ-SORS to determine whether two detected chemical components originate from two separate layers or whether the two components are mixed together in a single layer. Such information is important in a number of areas, including conservation of cultural heritage objects, and is not available, for highly turbid media, from conventional Raman microscopy, where axial (confocal) scanning is not possible due to an inability to facilitate direct imaging within the highly scattering sample. This application constitutes an additional capability for μ-SORS in addition to its basic capacity to determine the overall chemical make-up of layers in a turbid system

Grazing incidence synchrotron X-ray diffraction of marbles consolidated with diammonium hydrogen phosphate treatments : non-destructive probing of buried minerals

Diammonium hydrogen phosphate (DAP)-based consolidating treatments react with carbonatic stones and form calcium phosphates phases, whose composition depends on the availability of free calcium ions. In this work, an innovative non-destructive approach based on grazing incidence X-ray diffraction (GIXRD) with synchrotron radiation (SR) is used to investigate DAP-treated Carrara marble specimens and to study the influence of the substrate composition on the crystallization of calcium phosphate phases. The outcomes indicate that the presence of compositional micro-heterogeneity of Carrara marble favours the formation of specific phases. Dicalcium phosphate dihydrate, a calcium phosphate with a low Ca/P molar ratio, is formed on carbonatic phases with a low Ca amount, such as dolomite grains and Mg-containing veins. Furthermore, this study highlights the potentialities of SR-GIXRD as a powerful non-destructive tool for the diagnostic of Cultural Heritage objects since it allows investigating the conservation history of stone materials and their interaction with the environment

Synthesis of calcium oxalate trihydrate: new data by vibrational spectroscopy and synchrotron X-ray diffraction

Calcium oxalate is found in nature in three different crystalline states determined by the number of H2O in the unit formula (whewellite CaC2O4\ub7H2O, COM; weddellite CaC2O4\ub7(2 + x)H2O, COD and caoxite CaC2O4\ub73H2O, COT). The properties of these materials are relevant in the field of biomedicine, cultural heritage and mineralogy. In two previous papers, we have used X-ray diffraction and vibrational spectroscopy (infrared and Raman) to derive information on crystal and molecular structures of COM and COD. In this paper, we complete the synthesis and analysis on the third form, COT, and present a comparative study of the data collected from the three crystalline states. The experiments clearly highlight the role played by the H2O molecules linked within the structure by different kinds of hydrogen bonds. The vibrational assignment of the infrared and Raman bands are critically proposed. The fact relevant for the work in biomedicine, cultural heritage and crystallography is that a simple examination of the spectra allows quickly to determine the chemical nature of the material in an unknown sample even in a minute quantity or in awkward experimental conditions

Effects of whole linseed and rumen-protected conjugated linoleic acid enriched diets on beef quality

Instrumental assessments and sensory tests were performed to evaluate the effects of diet and postmortem ageing time (1, 7 and 21 days) on beef quality. A total of 48 Friesian calves were randomly allocated to four dietary treatments: control, whole linseed (10% linseed), conjugated linoleic acid (CLA) (2% protected CLA), and whole linseed+CLA (10% linseed and 2% protected CLA). Animals were slaughtered at 458±16.6 kg live weight and 11 months of age. Ageing was more significant than diet on most instrumental parameters. Meat from linseed enriched diets had greater drip loss (P=0.001) and intramuscular fat (P=0.01) than meat from animals fed CLA. Beef aged for 7 and 21 days had lower cooking losses (P=0.01) and shear force (P=0.001) than beef aged for 1 day. Lightness was affected only by display time. The addition of CLA in the diet increased hue and yellowness, whereas the inclusion of linseed decreased these values, as well as increased redness. Linseed in the diet decreased fat odour (P=0.05), but increased beef (P=0.01) and liver (P=0.05) flavours. Meat aged for 21 days was significantly more rancid (P=0.001), even under vacuum storage. Several organoleptic properties were improved with the inclusion of linseed in the diet, whereas they remained unaffected by the inclusion of CLA