112 research outputs found
Detecting nonlinear and many-body dynamics in nuclear quantum optics
In this thesis, different measurement and data evaluation approaches for the detection and characterization of collective nuclear level schemes arising in the low-excitation regime of thin-film x-ray cavities are discussed. The first approach uses Fourier transforms to analyze time- and frequency-resolved spectra recorded using nuclear reference absorbers. This allows for the extraction of the phase-resolved nuclear resonant response of the sample under investigation. Next, to study the dynamics of nuclear ensembles upon suitably-shaped x-ray light, a density matrix perturbation theory is presented that allows for the study of multi-level and many-body dynamics in the low-excitation regime of the x-ray-nuclei interaction. This method is used to interpret numerical data simulating several experimental scenarios: First, it is used to derive an equivalence between coherently and incoherently scattered x-ray intensity detectable in nuclear resonant scattering experiments, which serves as a criterion for nonlinear excitation of nuclear ensembles at coherent x-ray sources. Second, signatures of couplings between collective excited nuclear states in thin-film cavities upon differently-shaped x-ray pulses are proposed and identified in time-frequency-spectra. Finally, the feasibility of a specific coherent double pulse spectroscopic method under low-excitation conditions is discussed and numerically simulated spectra upon different double pulse sequences are compared
Effects of experience and electronic stability control on low friction collision avoidance in a truck driving simulator
Two experiments were carried out in a moving-base simulator, in which truck drivers of varying experience levels encountered a rear-end collision scenario on a low-friction road surface, with and without an electronic stability control (ESC) system. In the first experiment, the drivers experienced one instance of the rear-end scenario unexpectedly, and then several instances of a version of the scenario adapted for repeated collision avoidance. In the second experiment, the unexpected rear-end scenario concluded a stretch of driving otherwise unrelated to the study presented here. Across both experiments, novice drivers were found to collide more often than experienced drivers in the unexpected scenario. This result was found to be attributable mainly to longer steering reaction times of the novice drivers, possibly caused by lower expectancy for steering avoidance. The paradigm for repeated collision avoidance was able to reproduce the type of steering avoidance situation for which critical losses of control were observed in the unexpected scenario and, here, ESC was found to reliably reduce skidding and control loss. However, it remains unclear to what extent the results regarding ESC benefits in repeated avoidance are generalisable to unexpected situations. The approach of collecting data by appending one unexpected scenario to the end of an otherwise unrelated experiment was found useful, albeit with some caveats
A Review of Near-Collision Driver Behavior Models
Objective: This article provides a review of recent models of driver behavior in on-road collision situations.
Background: In efforts to improve traffic safety, computer simulation of accident situations holds promise as a valuable tool, for both academia and industry. However, to ensure the validity of simulations, models are needed that accurately capture near-crash driver behavior, as observed in real traffic or driving experiments.<p>
Method: Scientific articles were identified by a systematic approach, including extensive database searches. Criteria for inclusion were defined and applied, including the requirement that models should have been previously applied to simulate on-road collision avoidance behavior. Several selected models were implemented and tested in selected scenarios.<p>
Results: The reviewed articles were grouped according to a rough taxonomy based on main emphasis, namely avoidance by braking, avoidance by steering, avoidance by a combination of braking and steering, effects of driver states and characteristics on avoidance, and simulation platforms.<p>
Conclusion: A large number of near-collision driver behavior models have been proposed. Validation using human driving data has often been limited, but exceptions exist. The research field appears fragmented, but simulation-based comparison indicates that there may be more similarity between models than what is apparent from the model equations. Further comparison of models is recommended.<p>
Application: This review provides traffic safety researchers with an overview of the field of driver models for collision situations. Specifically, researchers aiming to develop simulations of on-road collision accident situations can use this review to find suitable starting points for their work
Berliner Revolutionschronik
BERLINER REVOLUTIONSCHRONIK
Berliner Revolutionschronik / Wolff, Gustav Adolf (Rights reserved - Rights managed by VG Wort (§ 51 VGG)) ( - )
Title page ( - )
Preface ( - )
Contents ([V])
Erstes Buch. Die Krisis ([1])
Zweites Buch. Die Revolution ([83])
Drittes Buch. Die Errungenschaften ([188])
Viertes Buch. Die politischen Parteien ([231])
FĂĽnftes Buch. Das Volk und seine Vertreter ([283])
Sechstes Buch. Das Ministerium Camphausen und die Nationalversammlung ([322])
Anhang. VerzeichniĂź der Abgeordneten zur PreuĂźischen Nationalversammlung ([383])
ColorChart ( -
Effect of Pretreatment Renal Function on Treatment and Clinical Outcomes in the Adjuvant Treatment of Older Women With Breast Cancer: Alliance A171201, an Ancillary Study of CALGB/CTSU 49907
CALGB 49907 showed the superiority of standard therapy, which included either cyclophosphamide/doxorubicin (AC) or cyclophosphamide/methotrexate/fluorouracil over single-agent capecitabine in the treatment of patients age ≥ 65 with early-stage breast cancer. The treatment allowed dosing adjustments of methotrexate and capecitabine for pretreatment renal function. The purpose of the current analysis was to assess the relationship between pretreatment renal function and five end points: toxicity, dose modification, therapy completion, relapse-free survival, and overall survival
The early bee catches the flower - circadian rhythmicity influences learning performance in honey bees, Apis mellifera
Circadian rhythmicity plays an important role for many aspects of honey bees’ lives. However, the question whether it also affects learning and memory remained unanswered. To address this question, we studied the effect of circadian timing on olfactory learning and memory in honey bees Apis mellifera using the olfactory conditioning of the proboscis extension reflex paradigm. Bees were differentially conditioned to odours and tested for their odour learning at four different “Zeitgeber” time points. We show that learning behaviour is influenced by circadian timing. Honey bees perform best in the morning compared to the other times of day. Additionally, we found influences of the light condition bees were trained at on the olfactory learning. This circadian-mediated learning is independent from feeding times bees were entrained to, indicating an inherited and not acquired mechanism. We hypothesise that a co-evolutionary mechanism between the honey bee as a pollinator and plants might be the driving force for the evolution of the time-dependent learning abilities of bees
Allergic rhinitis in South Africa – Update 2014
The SAARWG met on the 8th and 9th February 2014 to discuss and review
important concepts in allergic rhinitis diagnosis and management. The theme
of that meeting was to lead clinicians through the ideal „Allergy Clinic‟ and the
diagnostic facilities that may be offered to patients who present for
management at such a clinic. The content of that meeting forms the basis of
this update. The main reason for this statement is two-fold. Firstly, patients
with allergic diseases require careful examination and secondly, they may
need a set of diagnostic modalities. All physicians who see such patients must
be knowledgeable of the interpretation of such tests. This review will focus
specifically on the clinical tools and diagnostic modalities employed in the
management of those conditions.http://reference.sabinet.co.za/sa_epublication/cacihttp://www.allergysa.org/journal.htmhb201
Adjuvant Chemotherapy in Older Women with Early-Stage Breast Cancer
Older women with breast cancer are underrepresented in clinical trials, and data on the effects of adjuvant chemotherapy in such patients are scant. We tested for the noninferiority of capecitabine as compared with standard chemotherapy in women with breast cancer who were 65 years of age or older
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