206 research outputs found
A single-station model suitable for f0F2 mapping
No full textIonospheric monthly-median values of the F2 and E layer critical frequencies from 24 mid-latitude European stations are fitted to a second degree polynomial and their correlation is discussed. The resulting model is used to predict monthly-median f0F2 values for different ionospheric stations and for high, medium and low ionospheric activity. Finally, a potential application of the single station model developed for Slough to mapping the F2-layer critical frequency is investigated. Thus prediction of the monthly median f0F2 values for eight mid-latitude European stations is attempted using the single-station model of Slough and the corresponding F0E values of the station under investigation. The f0F2 values obtained are reasonably accurate. The main advantage of this method is its simplicity and the restricted number of parameters used.JCR Journalope
The mitochondrial genome of one ‘twisted-wing parasite’ Xenos cf. moutoni (Insecta, Strepsiptera, Xenidae) from Gaoligong Mountains, Southwest of China
No full textThe nearly complete mitochondrial genome (mitogenome) of Xenos cf. moutoni, one twisted-wing parasite on wasp Vespa velutina from Southwest of China, is described in this study. The total length of this mitogenome is 16,717 bp, containing 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and an incomplete A + T-rich control region . All of the 13 PCGs are initiated with canonical ATN (N represents A, T, G, C) as start codons; 8 PCGs are terminated with a complete typical stop codon TAA, and the remaining five PCGs (cox2, cox3, nad3, nad4 and nad5) have an incomplete stop codon with just a T. The phylogenetic analysis based on the nucleotide sequences of PCGs and rRNAs indicates that Xenos cf. moutoni has a close relationship with Xenos vesparum, confirming its placement in the family Xenidae
The effects of f0 F2 variability on TEC prediction accuracy
No full textIn this paper hourly daily F2-layer critical frequency data recorded at Rome and one minute daily TEC data recorded at Florence were used and the relevant variabiles were calculated. It was concluded that there was no clear evidence as to how they correlated. In order to obtain a measure of the f 0 F 2 and TEC variability, the normalised differences df0 F2 and d TEC from the relevant monthly median values were also considered. Since no clear evidence could be obtained as of how df0 F2 and d TEC correlate, a new parameter, the ?Ap /?R ratio was tried. ?Ap was taken as the difference between the maximum value of Ap measured at the relevant disturbance and that corresponding at the beginning of the disturbance. ?R corresponded to the two above mentioned values of Ap. This parameter was compared to the differences of the corresponding df0 F2 values called ?df and d TEC values called ?dT. In wintertime, when ?A p /? R was negative, for the vast majority of the occurrences either ?df or ?dT was negative; ?df and ?dT were never observed to be negative at the same time whereas they were both positive in fewer than 10% of the observations. When ?A p /?R was positive then either ?df or ?dT were negative. In summertime when ?A p /?R was negative both ?df and ?dT were negative. When ?A p /?R was positive, while a positive ?df corresponded almost always to a positive ?dT, a negative ?df would equiprobably indicate either a positive or a negative ?dT.PublishedJCR Journalope
A multiple receiver - multiple transmitter VLF high-order differential analysis evaluation network for near real-time detection and discrimination of seismic-ionospheric precursor phenomena
No full textApplication of differential analysis of VLF signals for seismic-ionospheric precursor detection from multiple receivers
No full textTen years analysis of Tropospheric refractivity variations
No full textThe refractivity variations of the troposphere are responsible for various effects on radio wave propagation, such as refraction, bending, radio-station interference, etc. In this work, the refractivity variations of the Hellenic
troposphere are studied using data from Helliniko airport of Athens/Greece. The data were analyzed using various interpolation procedures, i.e. in a day-by-day manner for temperature and relative humidity, to transform the data according to a reference height common for the whole dataset and finally for the refractivity
N with respect to time, using piece-wise hermite interpolation polynomials for the low and medium altitudes and linear interpolation factors for the high altitudes. Since refractivity varies with time and height, two height independent basic parameters were computed and analyzed: the refractivity at station height N0 and scale height Hs. These parameters can be used to calculate the refractivity profile. Using statistical tools as the moving average, the ß0 parameter and the monthly mean values, together with the corresponding standard deviations, useful results were obtained for the variations of the refractivity with respect to observation hour, height, season, month, day and level.PublishedJCR Journalope
The European Network for studying the radio precursors of earthquakes: the case of the May 19, 2011 Turkey earthquake (Mw=5.7)
No full textSince 2009 a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers was put into operation in Europe
in order to study the disturbances produced by the earthquakes on the propagation of these signals. In 2011 the
network was formed by nine receivers located three in Italy and one in Austria, Greece, Portugal, Romania,
Russia and Turkey. On May 19, 2001 an earthquake with Mw=5.7 occurred in western Turkey, that is inside
the “sensitive” area of the network. The radio data collected during April-May 2011 were studied using three
different methods of analysis which are the wavelet spectra, the principal component technique and the standard
deviation trends. Clear anomalies were revealed both in the signals broadcasted by the TRT transmitter (180 kHz)
located near Ankara and in some VLF signals coming from transmitters located in western Europe and collected
by the receiver TUR of the network located in eastern Turkey. Evident precursors phases were pointed out. Some
difference in the efficiency of the methods of analysis were revealed
The wall paintings of Xenos Digenis in the Myrtia monastery in Aetolia (1491)
No full textThe author examines the frescoes printed in 1491 by Xenos Digenis from Mouchli of Arcadia in the Catholics of the Myrtia Monastery, near Myrtia of Aetolia. These are the best-presented frescoes by Digenis, who also signed the frescoes in the churches of Aghioi Pateres at Apano Floria of Chania, Crete (1470) and the Dormition of the Virgin at Palaia Frastana (Kato Meropi) of Pogoni Epirus (1470, 1491). […]Αντικείμενο της εν λόγω διατριβής είναι η μελέτη των τοιχογραφιών που ζωγράφισε το 1491 ο Ξένος Διγενής από το Μουχλί της Αρκαδίας στο καθολικό της Μονής Μυρτιάς στην Αιτωλία. Ο ίδιο ζωγράφος είναι γνωστός και για τις ενυπόγραφες τοιχογραφίες του στους Αγίους Πατέρες στα Απάνω Φλώρια Σέλινου στο Νομό Χανίων της Κρήτης (1470) και στην Κοίμηση της Θεοτόκου στα Παλαιά Φραστανά, (σημερινή Κάτω Μερόπη) στο Πωγώνι της Ηπείρου (1470, 1491). […
The European Network for studying the radio precursors of earthquakes: Principal Component Analysis of LF radio signals collected during July 2009 - April 2011
No full textSince 2009 a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers was put into operation in Europe
in order to study the disturbances produced by the earthquakes on the propagation of these signals. In 2011 the
network for LF signals was formed by six receivers located two in Italy and one in Greece, Portugal, Romania,
and Turkey. The LF radio data collected during about two years have been analysed. Each radio signal has been
split in day-time and night-time data; then, the earthquakes with M
5.0, occurred in the same period, located in a
300 km radius around each receiver/transmitter and within the 5th Fresnel zone related to each transmitter-receiver
path, have been selected. In this study we adopt the Principal Component Analysis (PCA) to study the radio signal
anomalies possibly related to earthquake activity. A detailed comparison with similar studies that use wavelet analysis is done and advantages or drawback of the two methods are pointed out
Diferença de susceptibilidade a infecção com T. Cruzi entre espécies de Triatomíneos alimentados em cão, tatu e camundongo infectados.
No full textChamado antes como: Ineru. Núcleo de Pesquisas da Bahia do Instituto de Endemias Rurais.Diversas espécies de triatomíneos foram alimentadas em cão, tatu e camundongos infectados pelo T. cruzi, para verificação de suas susceptibilidades. Em cão T. infestans e P. megistus se infectaram melhor . Em tatus T. infestans e T. brasiliensis acusaram melhores índices de infecção, enquanto em camundongos as espécies de Rhodnius e T. brasiliensis foram as melhores infectadas . A positividade dos xenos não pareceu obrigatoriamente relacionada com a riqueza da parasitemia evidenciada através da hemoscopia direta . A positividade dos xenos em camundongos variou de 26 a 96%. Quando a mesma espécie de tria -
tomineos foi usada em tipos diversos de animais, pareceu haver uma tendência para apresentar em diferentes taxas de infecções, de acordo com o animal empregado.
Dessa forma , a susceptibilidade dos triatomíneos poderia estar dependente dos fatores: cepa do tripanosoma, espécie e fase do triatomíneo e o tipo do animal infectante
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