Decay chain fitting with a Kalman filter Hulsbergen, Wouter D.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2005, Letnik:
552, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We present a method to perform a least-squares fit of a decay chain involving multiple decay vertices. Our technique allows for the simultaneous extraction of decay time, position and momentum ...parameters and their uncertainties and correlations for all particles in a decay chain.
We present an expression for the covariance matrix of the set of state vectors describing a track fitted with a Kalman filter. We demonstrate that this expression facilitates the use of a Kalman ...filter track model in a minimum
χ
2
algorithm for the alignment of tracking detectors. We also show that it allows to incorporate vertex constraints in such a procedure without refitting the tracks.
Data of a 32-year field experiment (1967–1998), conducted on a fertile sandy loess in the Hercynian dry region of central Germany, were used to (i) demonstrate the methodological basis of energy ...balancing in a long-term trial and (ii) identify time trends of various energetic parameters, as affected by the rate and form of nitrogen (N) application. Of the 16 fertilizer regimes, 5 were selected to represent the broad range of N supply conditions: no N, mineral N only, farmyard manure N only, high input of both mineral and farmyard manure N, and moderate input of the two forms of N. The crop rotation included various cereals, sugar beets, and potatoes. In calculating the energy balances, changes in soil and crop husbandry practices over the past decades were taken into account. The input of energy associated with mineral N fertilization declined markedly with duration of the experiment, whereas the input of energy associated with chemical plant protection increased. The input of energy was highly variable; it ranged from 8.9 to 36.9
GJ
ha
−1 per year in the last crop rotation, depending on the N regime and the crop. Because of the high soil fertility, the average biomass yield of all the crops grown within a rotation was as high as 13.5
t
dry matter (DM)
ha
−1 per year; the output of energy was as high as 215
GJ
ha
−1 per year. On the fertilized plots, net energy output (energy content of the grains minus energy input) and energy utilization improved with time. Winter wheat, fertilized with moderate amounts of mineral and farmyard manure N, showed an increase in net energy output of 86% from 1972 to 1995. During the same period, the energy intensity (input of fossil energy per grain equivalent) declined by 45%, and the output/input ratio increased by 67%. In part, these trends can be attributed to the higher grain yield (+59%). Energy output and net energy output are the crucial parameters when the demand for plant products cannot be met because of the limited area for growing crops. Energy intensity and energy output/input ratio are integrative indicators of the environmental effects of crop production, which can be used to formulate recommendations for fertilization, which are optimum as far as the environment is concerned.
Purpose We determined the positive and negative predictive values of multiparametric magnetic resonance imaging for extraprostatic extension at radical prostatectomy for different prostate cancer ...risk groups. Materials and Methods We evaluated a cohort of 183 patients who underwent 3 Tesla multiparametric magnetic resonance imaging, including T2-weighted, diffusion weighted magnetic resonance imaging and dynamic contrast enhanced sequences, with an endorectal coil before radical prostatectomy. Pathological stage at radical prostatectomy was used as standard reference for extraprostatic extension. The cohort was classified into low, intermediate and high risk groups according to the D’Amico criteria. We recorded prevalence of extraprostatic extension at radical prostatectomy and determined sensitivity, specificity, positive predictive value and negative predictive value of multiparametric magnetic resonance imaging for extraprostatic extension in each group. Univariate and multivariate analyses were performed to identify predictors of extraprostatic extension at radical prostatectomy. Results The overall prevalence of extraprostatic extension at radical prostatectomy was 49.7% ranging from 24.7% to 77.1% between low and high risk categories. Overall staging accuracy of multiparametric magnetic resonance imaging for extraprostatic extension was 73.8%, with sensitivity, specificity, positive predictive value and negative predictive value of 58.2%, 89.1%, 84.1% and 68.3%, respectively. Positive predictive value of multiparametric magnetic resonance imaging for extraprostatic extension was best in the high risk cohort with 88.8%. Negative predictive value was highest in the low risk cohort with 87.7%. With an odds ratio of 10.3 multiparametric magnetic resonance imaging is by far the best preoperative predictor of extraprostatic extension at radical prostatectomy. Conclusions For adequate patient counseling, knowledge of predictive values of multiparametric magnetic resonance imaging for extraprostatic extension is of utmost importance. High negative predictive value, important for decisions on nerve sparing strategies at radical prostatectomy, is only reached in low risk subjects.
There is an ongoing forensic and security need for rapid, on-scene, easy-to-use, non-invasive chemical identification of intact energetic materials at pre-explosion crime scenes. Recent technological ...advances in instrument miniaturization, wireless transfer and cloud storage of digital data, and multivariate data analysis have created new and very promising options for the use of near-infrared (NIR) spectroscopy in forensic science. This study shows that in addition to drugs of abuse, portable NIR spectroscopy with multivariate data analysis also offers excellent opportunities to identify intact energetic materials and mixtures. NIR is able to characterize a broad range of chemicals of interest in forensic explosive investigations, covering both organic and inorganic compounds. NIR characterization of actual forensic casework samples convincingly shows that this technique can handle the chemical diversity encountered in forensic explosive investigations. The detailed chemical information contained in the 1350-2550 nm NIR reflectance spectrum allows for correct compound identification within a given class of energetic materials, including nitro-aromatics, nitro-amines, nitrate esters, and peroxides. In addition, the detailed characterization of mixtures of energetic materials, such as plastic formulations containing PETN (pentaerythritol tetranitrate) and RDX (trinitro triazinane), is feasible. The results presented illustrate that the NIR spectra of energetic compounds and mixtures are sufficiently selective to prevent false-positive results for a broad range of food-related products, household chemicals, raw materials used for the production of home-made explosives, drugs of abuse, and products that are sometimes used to create hoax improvised explosive devices. However, for frequently encountered pyrotechnic mixtures, such as black powder, flash powder, and smokeless powder, and some basic inorganic raw materials, the application of NIR spectroscopy remains challenging. Another challenge is presented by casework samples of contaminated, aged, and degraded energetic materials or poor-quality HMEs (home-made explosives), for which the spectral signature deviates significantly from the reference spectra, potentially leading to false-negative outcomes.
•Direct chemical screening of postal packages to detect fireworks.•Trace pyrotechnic residue detection with IRTD-DART-MS and CE with C4D.•Practical value demonstrated with swipes of seized ...parcels.•Differentiation of flash and black powder residues with IRTD-DART-MS.
High volume screening of parcels with the aim to trace the illegal distribution and selling of fireworks using postal services is challenging. Inspection services have limited manpower and means to perform extensive visual inspection. In this study, the presence of solid pyrotechnic residues collected from cardboard shipping parcels containing fireworks was investigated for direct in-field chemical detection. Two emerging trace detection techniques, i.e., capillary electrophoresis (CE)-based inorganic oxidizer detector and infrared thermal desorption (IRTD) coupled with direct analysis in real time mass spectrometry (DART-MS), were investigated for their potential as screening tools. Detection of non-visible pyrotechnic trace residues from real-case seized parcels was demonstrated using both screening techniques. However, the high nitrate background in the commercial CE system complicated its screening for black powder traces. IRTD-DART-MS allowed differentiation between flash and black powder by identification of the molecular inorganic ions. Compared to the portable CE instrument, rapid screening using IRTD-DART-MS is currently limited to laboratory settings. The capabilities of these emerging techniques established solid particle and trace residue chemical detection as interesting options for parcel screening in a logistic setting.
Background
The COVID-19 pandemic confronts healthcare workers, including neurosurgeons, with difficult choices regarding which patients to treat.
Methods
In order to assist ethical triage, this ...article gives an overview of the main considerations and ethical principles relevant when allocating resources in times of scarcity.
Results
We discuss a framework employing four principles: prioritizing the worst off, maximizing benefits, treating patients equally, and promoting instrumental value. We furthermore discuss the role of age and comorbidity in triage and highlight some principles that may seem intuitive but should not form a basis for triage.
Conclusions
This overview is presented on behalf of the European Association of Neurosurgical Societies and can be used as a toolkit for neurosurgeons faced with ethical dilemmas when triaging patients in times of scarcity.
The natural occurrence of 16 inorganic ions relevant to forensic explosives investigations on human hands was studied to support the evaluation of activity-level propositions when such traces are ...found on the hands or in the fingerprints of a suspect. A total of 594 hand swab extracts from 297 participants throughout Europe and the United States of America were analyzed using Ion Chromatography – Mass Spectrometry. The data provides a reference framework for future covert investigations and forensic casework. The results indicate that thiocyanate, chlorate, nitrite, lithium, strontium, and barium are rarely detected on the hands of individuals who have had no direct contact with explosives (P<0.03) and in quantities below 6 µg. Perchlorate contamination sporadically occurs without deliberately handling perchlorates (P=0.03), albeit at low levels (<12 µg). It also seems that the presence of perchlorate on hands is generally related to professions that involve explosives. Detecting substantial amounts of any of these rare ions on a suspect’s hands would require a specific explanation. Because legitimate activities exist that can also result in elevated levels of ions of interest on hands, the context surrounding their presence has to be carefully assessed for each individual case.
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•Quantitative reference assessment of 16 inorganic ions on hands using IC-MS.•Perchlorate or chlorate on hands seems indicative of contact with explosives.•Thiocyanate, (per)chlorate, nitrite, lithium, strontium, and barium are rare on hands.•The probability of innocent contamination is more easily assessed.
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