1,276 research outputs found
On the Underestimation of Flood Risk for Locationsdownstream from Flood Control Reservoirs
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Driver Drowsiness Immediately before Crashes – A Comparative Investigation of EEG Pattern Recognition
Periodogram and other spectral power estimation methods are established in quantitative EEG analysis. Their outcome in case of drowsy subjects fulfilling a sustained attention task is difficult to interpret. Two novel kind of EEG analysis based on pattern recognition were proposed recently, namely the microsleep (MS) and the alpha burst (AB) pattern recognition. We compare both methods by applying them to the same experimental data and relating their output variables to two independent variables of driver drowsiness. The latter was an objective lane tracking performance variable and the first was a subjective variable of self-experienced sleepiness. Results offer remarkable differences between both EEG analysis methodologies. The expected increase with time since sleep as well as with time on task, which also exhibited in both independent variables, was not identified after applying AB recognition. The EEG immediately before fatigue related crashes contained both patterns. MS patterns were remarkably more frequent before crashes; almost every crash (98.5 %) was preceded by MS patterns, whereas less than 64 % of all crashes had AB patterns within a 10 sec pre-crash interval
Why Matrix theory works for oddly shaped membranes
We give a simple proof of why there is a Matrix theory approximation for a
membrane shaped like an arbitrary Riemann surface. As corollaries, we show that
noncompact membranes cannot be approximated by matrices and that the Poisson
algebra on any compact phase space is U(infinity). The matrix approximation
does not appear to work properly in theories such as IIB string theory or
bosonic membrane theory where there is no conserved 3-form charge to which the
membranes couple.Comment: 8 pages, 4 figures, revtex; references adde
Just valid or even accurate? Determine the measurement accuracy of the pupillographic sleepiness test by applying self and observer ratings
Objective. The purpose of the present study was to provide validation and accuracy data for the pupillographic sleepiness test (PST), on the one hand, by applying self and observer ratings and, on the other hand, by fusioned self and observer ratings as a sleepiness reference value.Methods. A total of 30 healthy women and men participated in a partial sleep deprivation study (20.00–04.00 h) and PST measurements were conducted every 2 h for a total of 113 PST measurements. Karolinska Sleepiness Scale (KSS)-based self-reports and five video-based observer ratings of drowsiness (ORD) were measured immediately before the PST in order to provide reliable reference sleepiness values.Results. PST parameters (pupil unrest index, power of frequency) correlated significantly with the sleepiness validation criteria the KSS and ORD used in this study. Fusioned reference values obtained from one self-report and observer ratings showed a correlation of r = 0.54, a mean absolute percentage error of 1.58 KSS points, and an error of 35%.Conclusion. Our results indicate the moderate validity of the PST. Furthermore, the proposed sleepiness reference value might serve as a feasible intermediate solution to estimate sleepiness in the sense of a reference (“quasi-ground truth”) value. This might be true especially for within-subject designs with a focus on the time course of sleepiness. Moreover, the results might show the necessity to recalculate the thresholds of the current PST categories of sleepiness severity
T-Cell Non-Hodgkin Lymphomas: Spectrum of Disease and the Role of Imaging in the Management of Common Subtypes
T-cell non-Hodgkin lymphomas (NHLs) are biologically diverse, uncommon malignancies characterized by a spectrum of imaging findings according to subtype. The purpose of this review is to describe the common subtypes of T-cell NHL, highlight important differences between cutaneous, various peripheral and precursor subtypes, and summarize imaging features and the role of imaging in the management of this diverse set of diseases
Prognostic relevance of disseminated tumor cells in the bone marrow and biological factors of 265 primary breast carcinomas
Introduction The prognostic significance of disseminated tumor cells in the bone marrow (DTC-BM) of breast cancer patients has been demonstrated in many studies. Yet, it is not clear which of the primary tumors' biological factors predict hematogenous dissemination. We therefore examined `tissue micro arrays' (TMAs) of 265 primary breast carcinomas from patients with known bone marrow ( BM) status for HER2, Topoisomerase IIa ( Top IIa), Ki 67, and p53. Methods BM analysis was performed by cytospin preparation and immunocytochemical staining for cytokeratin (CK). TMAs were examined by immunohistochemistry (IHC) for HER2, Top IIa, Ki 67 and p53, and fluorescence in situ hybridization ( FISH) for HER2. Results HER2 ( 2+/ 3+) was positive in 35/167 (21%) cases ( FISH 24.3%), Top IIa (> 10%) in 87/187 (46%), Ki 67 in 52/ 184 (28%) and p53 (> 5%) in 61/174 cases (34%). Of 265 patients, 68 (25.7%) showed DTC-BM with a median of 2/2 x 106 cells ( 1 to 1,500). None of the examined factors significantly predicted BM positivity. Significant correlation was seen between HER2 IHC and Top IIa ( p = 0.06), Ki 67 ( p = 0.031), and p53 ( p <.001). Top IIa correlated with Ki 67 and p53, and Ki 67 also with p53 ( p = 0.004). After a median follow-up of 60.5 months ( 7 to 255), the presence of DTC-BM showed prognostic relevance for overall survival ( p = 0.03), whereas HER2 ( IHC, p = 0.04; FISH, p = 0.03) and Ki 67 ( p = 0.04) correlated with disease free survival, and HER2 with distant disease free survival ( IHC, p = 0.06; FISH, p = 0.05). Discussion The congruence of the examined factors' expression rates indicates a causal line of suppressor, proliferation, and mitosis markers, and growth factor receptors. Hematogenous tumor cell spread seems to be an independent process. The examination of these factors on DTC-BM is the aim of ongoing research
Insights into Chi recognition from the structure of an AddAB-type helicase–nuclease complex
Homologous recombination DNA repair requires double-strand break resection by helicase–nuclease enzymes. The crystal structure of bacterial AddAB in complex with DNA substrates shows that it employs an inactive helicase site to recognize ‘Chi' recombination hotspot sequences that regulate resection
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