43 research outputs found

    Distortion of meteor count rates due to cosmic radio noise and atmospheric particularities

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    The determination of the meteoroid flux is still a scientifically challenging task. This paper focusses on the impact of extraterrestrial noise sources as well as atmospheric phenomena on the observation of specular meteor echoes. The effect of cosmic radio noise on the meteor detection process is estimated by computing the relative difference between radio loud and radio quiet areas and comparing the monthly averaged meteor flux for fixed signal-to-noise ratios or fixed electron line density measurements. Related to the cosmic radio noise is the influence of D-layer absorption or interference with sporadic E-layers, which can lead to apparent day-to-day variation of the meteor flux of 15–20%

    Verbesserung der Osseointegration orthopädischer Implantate

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    In dieser Arbeit werden osteoinduktive Beschichtungsverfahren für orthopädische Implantate entwickelt. Für diese Untersuchungen werden zwei Implantatmodelle designt, die ganz bestimmte Charakteristika von orthopädischen Implantaten widerspiegeln. Die Charakterisierung der Modelle und der Beschichtung erfolgt durch experimentalphysikalische Untersuchungsmethoden. Die Beschreibung der Ossifikation wird durch die Auswertung von präklinischen In-vivo-Studien erbracht

    Long-term variability of mean winds in the mesosphere and lower thermosphere at low latitudes

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    Long-term variations of monthly mean zonal and meridional winds in the Mesosphere and Lower Thermosphere (MLT) at low-latitudes are analyzed using four medium frequency (MF) radars and three meteor radars located in the Asia-Oceania region. Radar data taken at close-by latitudes are appended to construct long-term data sets. With this, we have long-term data from five distinct latitudes within ±22° (viz., 22°N, ∼9°N, 0–2°N, 6–7°S and 21°S). The data length varies at different latitudes and spans a maximum of two decades during 1990–2010. The zonal winds show semiannual oscillation (SAO) at all locations with westward (eastward) winds during equinoxes (solstices). The month height pattern of SAO is similar within ±9° and is different at ±22°. The westward winds in the March equinox were enhanced every two or three years during 1990–2002. We define this phenomenon as Mesospheric Quasi-Biennial Enhancement (MQBE). Such signature is not clear after 2002. The meridional winds show annual oscillation (AO), with northward and southward winds during the December and June solstices, respectively. However, the timing at which the wind direction changes does not coincide at all latitudes. The amplitude of the AO is enhanced after 2004 and 2008 at ∼9°N and ∼7°S, respectively. Orthogonal components of SAO and AO are detected with persistent phase relation, which suggests that the zonal and meridional winds are coupled. The meridional winds show long-term trends at latitudes of ∼9°N and ∼6–7°S, but not at other latitudes. The zonal winds do not show significant long-term trends.N. Venkateswara Rao, T. Tsuda, D. M. Riggin, S. Gurubaran, I. M. Reid, and R. A. Vincen

    Early Detection and Monitoring of Cancer with the Anti-Malignin Antibody Test "

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    ABSTRACT: The serum anti-malignin antibody (AMA) test determines the antibody to malignin. a IO,OOO-Da peptide present in patients with a wide variety of cancers.l~ A total of 3315 double-blind tests demonstrated that AMA is a general transformation antibody, elevated in active no.nterminal cancer, regardless of the site or tissue type, with sensitivity and specificity of95% on the flTst determination and >99% on repeat determinations. - 9 Data have not however been published yet that indicate whether, in daily clinical practice, the AMA test provides accurate prospective and predictive information. Fony-two physicians from II states, who ordered the AMA test, performed blind, report here on their results on 208 determinations in the first consecutive 181 patients and controls. Used in monitoring treatment in 56 patients, the test predicted or agreed 94.1 % overall with the clinical status. Used in early detection in 125 patients and controls, of which 118 now have confirmed diagnoses. AMA was elevated in 21, all of whom were proven to have cancer; AMA was normal in 97, none of whom had cancer. Transient elevated AMA occurred in 3%, followed by normal values. Seven patients with still uncertain diagnosis who have had elevated AMA on repeated tests for I year or longer include six who are symptomatic, and three whose families have a high frequency of cancer. The conditions of these 7 may include undetected cancer because of the 118 with now certain diagnosis the AMA test predicted all correctly. From our experience, the AMA test should be used together with other routine procedures whenever signs and symptoms suggest cancer to facilitate early detection

    Global Dynamics of the MLT

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