Many individuals experience lower gastrointestinal tract symptoms, most commonly attributable to functional conditions. These individuals are frequently diagnosed with irritable bowel syndrome (IBS) ...based on their symptoms; however, some may require additional testing or referral to specialists before this diagnosis is made.
To systematically review the literature of the accuracy of individual symptoms and combinations of findings in diagnosing IBS.
Search of MEDLINE and EMBASE (up to June 2008) for prospective studies reporting on unselected cohorts of adult patients with lower gastrointestinal tract symptoms recorded before investigation.
Studies prospectively evaluating accuracy of individual symptoms or combinations of findings compared with results from investigations of the lower gastrointestinal tract.
Two authors independently assessed studies and extracted data to estimate likelihood ratios (LRs) of individual symptoms and combinations of findings in diagnosing IBS.
Ten studies evaluating 2355 patients were identified, with a summary prevalence of IBS following investigation of 57%. Individual symptom items yielded positive LRs from 1.2 (95% confidence interval CI, 0.93-1.6) for passage of mucus per rectum to 2.1 (95% CI, 1.4-3.0) for looser stools at onset of abdominal pain and negative LRs from 0.29 (95% CI, 0.12-0.72) for no lower abdominal pain to 0.88 (95% CI, 0.72-1.1) for no passage of mucus per rectum in diagnosing IBS. The Manning criteria had a summary positive LR of 2.9 (95% CI, 1.3-6.4) and a summary negative LR of 0.29 (95% CI, 0.12-0.71). The Rome I criteria had a positive LR of 4.8 (95% CI, 3.6-6.5) and a negative LR of 0.34 (95% CI, 0.29-0.41). The Kruis scoring system provided a summary positive LR of 8.6 (95% CI, 2.9-26.0) and a summary negative LR of 0.26 (95% CI, 0.17-0.41). The Rome II and III criteria have not been studied.
Individual symptoms have limited accuracy for diagnosing IBS in patients referred with lower gastrointestinal tract symptoms. The accuracy of the Manning criteria and Kruis scoring system were only modest. Despite strong advocacy for use of the Rome criteria, only the Rome I classification has been validated. Future research should concentrate on validating existing diagnostic criteria or developing more accurate ways of predicting a diagnosis of IBS without the need for investigation of the lower gastrointestinal tract.
Due to the periodic characteristics of SQUIDs, a suitable linearization technique is required for SQUID-based readout. Flux-ramp modulation is a common linearization technique and is typically ...applied for the readout of a microwave SQUID multiplexer as well as since recently also for dc-SQUIDs. Flux-ramp modulation requires another stage in the signal processing chain to demodulate the SQUID output signal before further processing. For cryogenic microcalorimeters, the signal contains events that are given by a fast exponentially rising and slowly exponentially decaying pulses shape. The events shall be detected by a trigger engine and recorded by a storage logic. Since the data rate can be decreased significantly by demodulation and event detection, it is desirable to do both steps on the deployed fast FPGA logic during measurement before passing the data to a general-purpose processor. In this contribution, we show the implementation of efficient multi-channel flux-ramp demodulation computed at run-time on a SoC-FPGA. Furthermore, a concept and implementation for an online trigger and buffer mechanism with its theoretical trigger loss rates depending on buffer size is presented. Both FPGA modules can be operated with up to 500 MHz clock frequency and can efficiently process 32 channels. Correct functionality and data reduction capability of the modules are demonstrated in measurements utilizing magnetic microcalorimeter irradiated with an Iron-55 source for event generation and read out by a microwave SQUID multiplexer.
Nailfold capillaroscopy is a rapid and easily applicable differential diagnostic technique that allows direct visualization of the microcirculation. Abnormal findings in nailfold capillaroscopy are ...closely associated with connective tissue diseases, such as systemic sclerosis. The clinical manifestation of impaired microcirculation is Raynaud's phenomenon, which is a classical symptom of connective tissue diseases. Nailfold capillaroscopy is increasingly used in various fields of medicine, therefore it is important to define methods for the acquisition and analysis of the results of nailfold capillary and to have a uniform definition of abnormal capillaries. This article discusses image acquisition and analysis, various capillaroscopic techniques, normal and abnormal capillaroscopic features and their significance, scoring systems and reliability of image acquisition and interpretation.
Metallic magnetic calorimeters (MMCs) are highly linear cryogenic detectors that offer an excellent energy resolution, a signal rise time of <100 ns, and a high dynamic range. MMCs are of high ...interest for many experiments. One of them, i.e., the Electron Capture (EC) in 163 Ho (ECHo) experiment, requires the utilization of large MMC detector arrays. The readout of such MMC arrays is a challenging task, which can be tackled using software-defined radios (SDRs). Although SDR is a well-known approach in communications engineering, a dedicated implementation for frequency division multiplexed readout of MMCs is new and one of the technological key elements of the ECHo project. ECHo will be the first experiment to use microwave superconducting quantum interference device (SQUID) multiplexed MMC detectors, and therefore, pioneering the hardware, firmware, and software development in this domain. This paper presents the detailed concepts and current status of the development.
The coordination of plant leaf water potential (ΨL) regulation and xylem vulnerability to embolism is fundamental for understanding the tradeoffs between carbon uptake and risk of hydraulic damage. ...There is a general consensus that trees with vulnerable xylem more conservatively regulate ΨL than plants with resistant xylem. We evaluated if this paradigm applied to three important eastern US temperate tree species, Quercus alba L., Acer saccharum Marsh. and Liriodendron tulipifera L., by synthesizing 1600 ΨL observations, 122 xylem embolism curves and xylem anatomical measurements across 10 forests spanning pronounced hydroclimatological gradients and ages. We found that, unexpectedly, the species with the most vulnerable xylem (Q. alba) regulated ΨL less strictly than the other species. This relationship was found across all sites, such that coordination among traits was largely unaffected by climate and stand age. Quercus species are perceived to be among the most drought tolerant temperate US forest species; however, our results suggest their relatively loose ΨL regulation in response to hydrologic stress occurs with a substantial hydraulic cost that may expose them to novel risks in a more drought‐prone future.
Summary Statement
Across 10 diverse eastern US stands, anisohydric Quercus alba possessed more embolism‐vulnerable stems than isohydric Acer saccharum and Liriodendron tulipifera. Although oaks are often considered drought‐tolerant species, Q. alba sustains gas exchange by operating with heightened risk for hydraulic dysfunction.
In a companion paper (Bastian et al. 2007, this issue) we introduced an abstract definition of a parallel and adaptive hierarchical grid for scientific computing. Based on this definition we derive ...an efficient interface specification as a set of C++ classes. This interface separates the applications from the grid data structures. Thus, user implementations become independent of the underlying grid implementation. Modern C++ template techniques are used to provide an interface implementation without big performance losses. The implementation is realized as part of the software environment DUNE (
http://dune-project.org/
). Numerical tests demonstrate the flexibility and the efficiency of our approach.
The electron capture in 163Ho experiment – ECHo Gastaldo, L.; Blaum, K.; Chrysalidis, K. ...
The European physical journal. ST, Special topics,
06/2017, Letnik:
226, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak ...interactions, in particular of the
3
H β-decay and the
163
Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in
163
Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide
163
Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the
163
Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure
163
Ho samples, the identification and suppression of background sources as well as the precise parametrization of the
163
Ho EC spectrum are of utmost importance. The high-energy resolution
163
Ho spectra measured with the first MMC prototypes with ion-implanted
163
Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq
163
Ho will allow to reach a neutrino mass sensitivity below 10 eV/
c
2
. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq
163
Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass.
We give a mathematically rigorous definition of a grid for algorithms solving partial differential equations. Unlike previous approaches (Benger 2005, PhD thesis; Berti 2000, PhD thesis), our grids ...have a hierarchical structure. This makes them suitable for geometric multigrid algorithms and hierarchical local grid refinement. The description is also general enough to include geometrically non-conforming grids. The definitions in this article serve as the basis for an implementation of an abstract grid interface as C++ classes in the framework (Bastian et al. 2008, this issue).
PDF
