2,876 research outputs found
Atmospheric ionization and cosmic rays: studies and measurements before 1912
The discovery of cosmic rays, a milestone in science, was based on the work
by scientists in Europe and the New World and took place during a period
characterised by nationalism and lack of communication. Many scientists that
took part in this research a century ago were intrigued by the penetrating
radiation and tried to understand the origin of it. Several important
contributions to the discovery of the origin of cosmic rays have been
forgotten; historical, political and personal facts might have contributed to
their substantial disappearance from the history of science.Comment: Presented at the conference "100 Years Cosmic Ray Physics -
Anniversary of the V.F. Hess Discovery"; 6 - 8 August, Bad Saarow/Pieskow,
Germany (the place where Hess landed 7th Aug 1912 after discovery
Linksradikaler Theologe. Karl Barth stand nicht im Dienst der DDR. Ihm ging der Sozialismus nicht weit genug
Biotopverbund und Eingriffsregelung am Beispiel der Ortsumfahrung Schönebeck
Bereits im Jahr 1997 wurde mit der Erstellung der naturschutzfachlichen Planunterlagen für die Planfeststellung der Ortsumfahrung Schönebeck im Zuge der B 246a in der Magdeburger Börde begonnen. Bereits für den 1. Planungsabschnitt von der Bundesautobahn A 14 bis zur L 65 wurde im Rahmen der naturschutzrechtlichen Kompensation der Schwerpunkt auf den Biotopverbund und die Stärkung vorhandener Strukturen als Kerne dieses Verbundes gelegt. Zu nennen sind hier v. a. die Endmoränenkuppen südlich von Schönebeck wie der Spitze Berg. Mögliche Beeinträchtigungen des Biotopverbundes durch Verkehrsinfrastrukturvorhaben können sich insbesondere durch die Zerschneidungseffekte derartiger linearer Vorhaben ergeben. Ein vorrangiges Ziel muss es deshalb sein, diese Effekte zu minimieren, indem einerseits die Inanspruchnahme von wertvollen Biotopverbundstrukturen vermindert und andererseits die Durchlässigkeit der Verkehrstrassen für die Fauna durch geeignete Maßnahmen wie Wild- und Amphibiendurchlässe oder Grünbrücken verbessert wird
Specificity of the human frequency following response for carrier and modulation frequency assessed using adaptation
The frequency following response (FFR) is a scalp-recorded measure of phase-locked brainstem activity to stimulus-related periodicities. Three experiments investigated the specificity of the FFR for carrier and modulation frequency using adaptation. FFR waveforms evoked by alternating-polarity stimuli were averaged for each polarity and added, to enhance envelope, or subtracted, to enhance temporal fine structure information. The first experiment investigated peristimulus adaptation of the FFR for pure and complex tones as a function of stimulus frequency and fundamental frequency (F0). It showed more adaptation of the FFR in response to sounds with higher frequencies or F0s than to sounds with lower frequency or F0s. The second experiment investigated tuning to modulation rate in the FFR. The FFR to a complex tone with a modulation rate of 213 Hz was not reduced more by an adaptor that had the same modulation rate than by an adaptor with a different modulation rate (90 or 504 Hz), thus providing no evidence that the FFR originates mainly from neurons that respond selectively to the modulation rate of the stimulus. The third experiment investigated tuning to audio frequency in the FFR using pure tones. An adaptor that had the same frequency as the target (213 or 504 Hz) did not generally reduce the FFR to the target more than an adaptor that differed in frequency (by 1.24 octaves). Thus, there was no evidence that the FFR originated mainly from neurons tuned to the frequency of the target. Instead, the results are consistent with the suggestion that the FFR for low-frequency pure tones at medium to high levels mainly originates from neurons tuned to higher frequencies. Implications for the use and interpretation of the FFR are discussed
Prospective, open, multi-centre phase I/II trial to assess safety and efficacy of neoadjuvant radiochemotherapy with docetaxel and oxaliplatin in patients with adenocarcinoma of the oesophagogastric junction
Background: This phase I/II-trial assessed the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) of neoadjuvant radiochemotherapy (RCT) with docetaxel and oxaliplatin in patients with locally advanced adenocarcinoma of the oesophagogastric junction.
Methods: Patients received neoadjuvant radiotherapy (50.4 Gy) together with weekly docetaxel (20 mg/m2 at dose level (DL) 1 and 2, 25 mg/m2 at DL 3) and oxaliplatin (40 mg/m2 at DL 1, 50 mg/m2 at DL 2 and 3) over 5 weeks. The primary endpoint was the DLT and the MTD of the RCT regimen. Secondary endpoints included overall response rate (ORR) and progression-free survival (PFS).
Results: A total of 24 patients were included. Four patients were treated at DL 1, 13 patients at DL 2 and 7 patients at DL 3. The MTD of the RCT was considered DL 2 with docetaxel 20 mg/m2 and oxaliplatin 50 mg/m2. Objective response (CR/PR) was observed in 32% (7/22) of patients. Eighteen patients (75%) underwent surgery after RCT. The median PFS for all patients (n = 24) was 6.5 months. The median overall survival for all patients (n = 24) was 16.3 months. Patients treated at DL 2 had a median overall survival of 29.5 months.
Conclusion: Neoadjuvant RCT with docetaxel 20 mg/m2 and oxaliplatin 50 mg/m2 was effective and showed a good toxicity profile. Future studies should consider the addition of targeted therapies to current neoadjuvant therapy regimens to further improve the outcome of patients with advanced cancer of the oesophagogastric junction.
Trial Registration: NCT0037498
Teologija na tržištu
One task intended to measure sensitivity to temporal fine structure (TFS) involves the discrimination of a harmonic complex tone from a tone in which all harmonics are shifted upwards by the same amount in hertz. Both tones are passed through a fixed bandpass filter centered on the high harmonics to reduce the availability of excitation-pattern cues and a background noise is used to mask combination tones. The role of frequency selectivity in this "TFS1" task was investigated by varying level. Experiment 1 showed that listeners performed more poorly at a high level than at a low level. Experiment 2 included intermediate levels and showed that performance deteriorated for levels above about 57 dB sound pressure level. Experiment 3 estimated the magnitude of excitation-pattern cues from the variation in forward masking of a pure tone as a function of frequency shift in the complex tones. There was negligible variation, except for the lowest level used. The results indicate that the changes in excitation level at threshold for the TFS1 task would be too small to be usable. The results are consistent with the TFS1 task being performed using TFS cues, and with frequency selectivity having an indirect effect on performance via its influence on TFS cues. (C) 2015 Acoustical Society of America
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