Science.gov

Sample records for roti sreluu posttraumaatilise

  1. The impact of different sampling rates and calculation time intervals on ROTI values

    NASA Astrophysics Data System (ADS)

    Jacobsen, Knut Stanley

    2014-11-01

    The ROTI (Rate of TEC index) is a commonly used measure of ionospheric irregularities level. The algorithm to calculate ROTI is easily implemented, and is the same from paper to paper. However, the sample rate of the GNSS data used, and the time interval over which a value of ROTI is calculated, varies from paper to paper. When comparing ROTI values from different studies, this must be taken into account. This paper aims to show what these differences are, to increase the awareness of this issue. We have investigated the effect of different parameters for the calculation of ROTI values, using one year of data from 8 receivers at latitudes ranging from 59° N to 79° N. We have found that the ROTI values calculated using different parameter choices are strongly positively correlated. However, the ROTI values are quite different. The effect of a lower sample rate is to lower the ROTI value, due to the loss of high-frequency parts of the ROT spectrum, while the effect of a longer calculation time interval is to remove or reduce short-lived peaks due to the inherent smoothing effect. The ratio of ROTI values based on data of different sampling rate is examined in relation to the ROT power spectrum. Of relevance to statistical studies, we find that the median level of ROTI depends strongly on sample rate, strongly on latitude at auroral latitudes, and weakly on time interval. Thus, a baseline "quiet" or "noisy" level for one location or choice or parameters may not be valid for another location or choice of parameters.

  2. Longitude dependent response of the GPS derived ionospheric ROTI to geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Tanna, H. J.; Pathak, K. N.

    2014-08-01

    The local time dependent effects of geomagnetic storm on the ionospheric TEC and Rate of change of TEC Index (ROTI) are studied here using the GPS data for four different low latitude stations: Ogaswara, Japan (24.29 °N, 153.91 °E; Geomagnetic: 17.21 °N, 136.16 °W); Surat, India (21.16 °N, 72.78 °E; Geomagnetic: 12.88 °N, 146.91 °E); Bogota, Colombia (4.64 °N, -74.09 °E; Geomagnetic: 14.42 °N, 1.67 °W); and Kokee park Waimea, Hawaii, US (22.12 °N, -159.67 °E; Geomagnetic: 22.13 °N, 91.19 °W). The solar wind velocity and geomagnetic indices: Dst, Kp and IMF Bz are utilized to validate the geomagnetic storms registered during the years 2011 and 2012. Using the GPS based TEC data and computed values of ROTI, the storm induced ionospheric irregularities generation and inhibition has been studied for all stations. The present study suggests that, the F-region irregularities of a scale length of few kilometers over the magnetic equator are locally affected by geomagnetic storms. This study also shows a good agreement (70-84 %) with the Aaron's criteria (Aarons, Radio Sci., 26:1131-1149, 1991; Biktash, Ann. Geophys., 19:731-739, 2004) as significant absence and enhancement of ROTI was found to be influenced by the local time of the negative peak of Dst index association.

  3. Effect of particle size of rice flour on physical and sensory properties of Sel-roti.

    PubMed

    Subba, Dilip; Katawal, Surendra Bahadur

    2013-02-01

    Sel-roti is a delicious, deep-fat fried, puffed, ring shaped spongy doughnut like Nepalese indigenous food prepared from the batter of rice flour, ghee and sugar. A study was conducted to determine the effect of particle size of rice flour on bulk density, oil uptake and texture of Sel-roti. Rice was soaked in water and ground with the help of iron mortar and pestle and the flour was analyzed for particle size distribution by using standard sieves and separated into three particle size categories as coarse (> 890 u), medium (120-890 u) and fine (< 120 u). The rice flour of different particle sizes were mixed in different proportions and Sel-roti was prepared from these flours. Bulk density and oil uptake were determined and sensory test was carried out. The results showed significant good positive correlation between mean particle size and bulk density (r = 0.97, p ≤ 0.05) and a good negative correlation between mean particle size and oil-uptake (r = 0.90, p ≤ 0.05). Good positive correlation of mean particle size with texture attributes like hardness (r = 0.99, p ≤ 0.05) and fracturability (r = 0.96, p ≤ 0.05) and good negative correlation with smoothness (r  = -0.97, p ≤ 0.05), cohesiveness (r = -0.92, p ≤ 0.05), stickiness (r = -0.76, p ≤ 0.05) and oily mouth feel (r = -0.85, p ≤ 0.05) and fair positive correlation with chewiness (r = 0.65, p > 0.05) were found. PMID:24425906

  4. Day-to-day variability of VTEC and ROTI in October 2012 with impact of high-speed solar wind stream on 13 October 2012

    NASA Astrophysics Data System (ADS)

    Azzouzi, I.; Migoya-Orue, Y. O.; Coisson, P.; Amory Mazaudier, C.; Fleury, R.; Radicella, S. M.

    2016-03-01

    This paper presents the day-to-day variability of the Vertical Total Electron Content (VTEC) and the Rate of change of TEC Index (ROTI) in October 2012. We focused our attention to the impact of a high-speed solar wind stream (HSSWS) on the ionosphere in middle and low latitudes on 13 October 2012. This event was preceded by two other disturbances caused by a Coronal Mass Ejection (CME) at 05:26UT on 8 October and a HSSWS around 19:00UT on 9 October. The changes in the VTEC observed during the period between 8 and 12 October preceding the 13 October case showed a comparable response of the ionosphere in both hemispheres, varying mainly with latitude and presenting a stronger impact in the Northern hemisphere. The VTEC increased at the arrival of the CME on 8 October, then decreased, and increased again on 13 October. The solar wind speed associated with the second HSSWS reached its peak, 580 km/s around 17:00UT during the recovery phase of a geomagnetic storm started around 00:00UT on 13 October. Its impact was observed in Africa and in Eastern South America on the ROTI, an indicator of ionospheric scintillation. On 13 October, the ROTI was small over whole Africa and in Eastern South America at the moment the impact of the second HSSWS. These observations are interpreted as due to the ionospheric disturbance dynamo electric field associated with the Joule heating produced in the auroral zone by the HSSWS.

  5. Measuring Ionospheric Irregularities Globally by the Rate of TEC Index and GNSS Networks

    NASA Technical Reports Server (NTRS)

    Pi, Xiaoqing

    2012-01-01

    Outline of presentation: Why do we use the rate of TEC index (ROTI) instead of the standard s4 and sigma-phi indices? What are the differences between S4, sigma-phi and ROTI? Examples of ROTI measurements and Development status and plan.

  6. Analysing Enterprise Returns on Training.

    ERIC Educational Resources Information Center

    Moy, Janelle; McDonald, Rod

    Recent Australian and overseas studies on evaluation of enterprises' return on training investment (ROTI) were reviewed to identify key issues in encouraging increased evaluation of training benefits by enterprises and successful approaches that may inform future "enterprise-friendly" studies of ROTI. It was concluded that more practical,…

  7. Observations of Global and Regional Ionospheric Irregularities and Scintillation Using GNSS Tracking Networks

    NASA Technical Reports Server (NTRS)

    Pi, Xiaoqing; Mannucci, Anthony J.; Valant-Spaight, Bonnie; Bar-Sever, Yoaz; Romans, Larry J.; Skone, Susan; Sparks, Lawrence; Hall, G. Martin

    2013-01-01

    The rate of TEC index (ROTI) is a measurement that characterizes ionospheric irregularities. It can be obtained from standard GNSS dual-frequency phase data collected using a geodetic type of GNSS receiver. By processing GPS data from ground-based networks of International GNSS Service and Continuously Operating Reference Station (CORS), ROTI maps have been produced to observe global and regional scintillation activities. A major mid-latitude scintillation event in the contiguous United States is reported here that was captured in ROTI maps produced using CORS GPS data collected during a space weather storm. The analyses conducted in this work and previously by another group indicate that ROTI is a good occurrence indicator of both amplitude and phase scintillations of GPS L-band signals, even though the magnitudes of ROTI, S4, and sigma(sub phi) can be different. For example, our analysis indicates that prominent ROTI and the L1 phase scintillation (sigma(sub phi)) are well correlated temporally in the polar region while L1 amplitude scintillation rarely occurs. The differences are partially attributed to physics processes in different latitude regions, such as high-speed plasma convection in the polar region that can suppress the amplitude scintillation. An analysis of the impact of ionospheric scintillation on precise positioning, which requires use of dual-frequency phase data, is also conducted. The results indicate that significant (more than an order of magnitude) positioning errors can occur under phase scintillation conditions.

  8. A comparison of TEC fluctuations and scintillations at Ascension Island

    NASA Astrophysics Data System (ADS)

    Basu, S.; Groves, K. M.; Quinn, J. M.; Doherty, P.

    1999-11-01

    With increasing reliance on space-based platforms for global navigation and communication, concerns about the impact of ionospheric scintillation on these systems have become a high priority. Recently, the Air Force Research Laboratory (AFRL) performed amplitude scintillation measurements of L1 (1.575 MHz) signals from GPS satellites at Ascension Island (14.45° W, 7.95° S; magnetic latitude 16° S) during February-April, 1998, to compare amplitude scintillations with fluctuations of the total electron content (TEC). Ascension Island is located in the South Atlantic under the southern crest of the equatorial anomaly of F2 ionization where scintillations will be much enhanced during the upcoming solar maximum period. Ascension Island is included in the global network of the International GPS Service (IGS) and the GPS receivers in this network report the carrier to noise (C/N) ratio, the dual frequency carrier phase and pseudorange data at 30-s intervals. Such data with a sampling interval of 30 s were analyzed to determine TEC, the rate of change of TEC (ROT) and also ROTI, defined as the standard deviation of ROT. The spatial scale of ROTI, sampled at 30 s interval, will correspond to 6 km when the vector sum of the ionospheric projection of the satellite velocity and the irregularity drift orthogonal to the propagation path is of the order of 100 m/s. On the other hand, the scale-length of the amplitude scintillation index corresponds to the Fresnel dimension which is about 400 m for the GPS L1 frequency and an ionospheric height of 400 km. It is shown that, in view of the co-existence of large and small scale irregularities in equatorial irregularity structures, during the early evening hours, and small magnitude of irregularity drifts, ROTI measurements can be used to predict the presence of scintillation causing irregularities. The quantitative relationship between ROTI and S4, however, varies considerably due to variations of the ionospheric projection of the

  9. Distributions of TEC Fluctuations and Losses of Lock Associated with Equatorial Plasma Bubbles

    NASA Astrophysics Data System (ADS)

    Nakata, H.; Kikuchi, H.; Tsugawa, T.; Otsuka, Y.; Takano, T.; Shimakura, S.; Shiokawa, K.; Ogawa, T.

    2009-12-01

    Equatorial plasma bubbles (EPBs) are local depletions of the electron density in the ionosphere. Due to field-aligned irregularities (FAIs) with various spatial scales, EPBs affect wide-band radio waves and cause scintillations in GPS navigation system. Strong scintillation can cause a GPS receiver to lose lock on GPS signals because of rapid variations of signal amplitude and phase, and limit the availability of carrier phase measurements. Since the scintillation is caused by Fresnel diffraction, the spatial scale of FAIs that causes the scintillation of GPS signals is about 2-300 m. Therefore, loss of phase lock (LOL) on GPS signals is a reference of hundred-meter-scale FAIs. As EPBs are also associated with fluctuations of the total electron content (TEC), the enhancement of Rate of TEC change index (ROTI) occurs around EPBs. Assuming that the altitude of the ionosphere is about 400 km, the velocity of the pierce point of the GPS radio wave at the ionospheric altitude is approximately 70 m/s around the zenith. Thus, ROTI averaged during 5 minutes is a reference of ten-kilometer-scale fluctuations. In this study, we analyzed LOL and 5-min. ROTI associated with EPBs to examine the spatial and temporal scales of electron density disturbances associated with EPBs. We selected 11 EPBs from 630-nm airglow images obtained by all-sky imager at Sata, Japan, in 2001. LOL and ROTI are obtained from GPS data from GPS Earth Observation Network (GEONET) of Japan, which consists of more than 1000 GPS receivers. As a result, it is shown that both LOL and the enhancement of ROTI are observed in 8 events out of 11 events. The distributions of LOL are approximately consistent with the areas in which the ionospheric electron density is depleted. The enhancements of ROTI are observed in the vicinities of EPBs. The enhancement of ROTI expands especially in the west side of EPBs. After the EPBs pass through, therefore, LOLs are vanished but the enhancements of ROTI last a while. This

  10. Studies of Plasma Bubbles & Comparision of TEC Fluctuations and Scintillations at Varanasi Using GPS Data

    NASA Astrophysics Data System (ADS)

    Priyadarshi, Shishir; Kumar, Sanjay; Singh, Abhay Kumar

    Ionospheric total electron content (TEC) and scintillations have been recorded continuously since January 2009 using a dual frequency GPS receiver at Varanasi, India (geographic lat. 25.30 N, long. 82.990 E). The trajectory of a GPS satellite plays an important role in observing the bubble characteristics. The GPS data with a sampling interval of 60 s were analyzed to determine TEC, the rate of change of TEC (ROT) and as well as ROTI, defined as the standard deviation of ROT. In this work we compare the S4 index of GPS scintillations with the ROTI values and there by investigated the evolution of large and small scale irregularities at scale length of few kilometers and 400 m respectively observed at low latitude station Varanasi. The effects of geomagnetic activity and geomagnetic storm on the generation of bubbles are studied using Kp index and Dst index respectively. Kew words: GPS, Plasma bubble, ROT, ROTI

  11. Observation of the ionospheric irregularities over the Northern Hemisphere: Methodology and service

    NASA Astrophysics Data System (ADS)

    Cherniak, Iurii; Krankowski, Andrzej; Zakharenkova, Irina

    2014-08-01

    Observation and analysis of the ionospheric irregularities at the high latitudes using GPS measurements represent very actual task for both scientific point of view and Global Navigation Satellite Systems (GNSS) applications, as the occurrence of the ionospheric irregularities can impact a variety of communication and navigation systems. In this paper we describe methodology and service for continuous generation of high-resolution maps of the ionospheric irregularities. To observe the high-latitude ionospheric irregularities, data collected from three ground-based GPS networks of the Northern Hemisphere are processed and analyzed. Here we used parameters ROT (rate of total electron content (TEC) change) and ROTI (index of ROT) to study the occurrence of TEC fluctuations Pi et al.. ROTI maps are constructed with the grid of 2° × 2° resolution as a function of the magnetic local time and corrected magnetic latitude. The ROTI maps allow to estimate the overall fluctuation activity and auroral oval evolutions, in general, the ROTI values are corresponded to the probability of the GPS signals phase fluctuations. We demonstrate that the occurrence and magnitude of TEC fluctuations, measured using GNSS networks, increase dramatically during space weather events. The irregularities oval expands considerably equatorward with simultaneous increase of the fluctuation intensity.

  12. The Lamaholot Language of Eastern Indonesia

    ERIC Educational Resources Information Center

    Nagaya, Naonori

    2011-01-01

    This study presents the grammar of the Lewotobi dialect of Lamaholot, an Austronesian language spoken in the eastern part of Flores Island and neighboring islands of Indonesia. Lamaholot belongs to the Central Malayo-Polynesian subgroup of Austronesian, within which it is in a subgroup with the languages of Timor and Roti. The number of speakers…

  13. Evaluation of the impact of ionospheric disturbances on air navigation augmentation system using multi-point GPS receivers

    NASA Astrophysics Data System (ADS)

    Omatsu, N.; Otsuka, Y.; Shiokawa, K.; Saito, S.

    2013-12-01

    In recent years, GPS has been utilized for navigation system for airplanes. Propagation delays in the ionosphere due to total electron content (TEC) between GPS satellite and receiver cause large positioning errors. In precision measurement using GPS, the ionospheric delay correction is generally conducted using both GPS L1 and L2 frequencies. However, L2 frequency is not internationally accepted as air navigation band, so it is not available for positioning directly in air navigation. In air navigation, not only positioning accuracy but safety is important, so augmentation systems are required to ensure the safety. Augmentation systems such as the satellite-based augmentation system (SBAS) or the ground-based augmentation system (GBAS) are being developed and some of them are already in operation. GBAS is available in a relatively narrow area around airports. In general, it corrects for the combined effects of multiple sources of positioning errors simultaneously, including satellite clock and orbital information errors, ionospheric delay errors, and tropospheric delay errors, using the differential corrections broadcast by GBAS ground station. However, if the spatial ionospheric delay gradient exists in the area, correction errors remain even after correction by GBAS. It must be a threat to GBAS. In this study, we use the GPS data provided by the Geographical Survey Institute in Japan. From the GPS data, TEC is obtained every 30 seconds. We select 4 observation points from 24.4 to 35.6 degrees north latitude in Japan, and analyze TEC data of these points from 2001 to 2011. Then we reveal dependences of Rate of TEC change Index (ROTI) on latitude, season, and solar activity statistically. ROTI is the root-mean-square deviation of time subtraction of TEC within 5 minutes. In the result, it is the midnight of the spring and the summer of the solar maximum in the point of 26.4 degrees north latitude that the value of ROTI becomes the largest. We think it is caused by

  14. GNSS monitoring of the ionospheric irregularities over the Northern Hemisphere for Space Weather applications

    NASA Astrophysics Data System (ADS)

    Krankowski, Andrzej; Cherniak, Iurii; Zakharenkova, Irina

    2014-05-01

    Passing through the ionosphere GNSS radio signals are subjected to rapid variations of their amplitude and phase and, from the other side, they can be used to reveal the strong ionosphere fluctuation events. Currently, there is a demand to increase the precision and reliability of GNSS positioning by taking into account of the ionosphere's variatiability, both regular and irregular. The regular behavior of the ionosphere is effectively studied with use of the global ionospheric maps (GIMs TEC) produced by IGS community. Also several research groups have developed techniques for creation the ionospheric irregularities maps. Such maps can be useful for space weather monitoring, radioastronomy and navigation by combining them with global ionospheric TEC maps. Our investigation is based on the classical approach when Rate of TEC (ROT) is detrended rate of line-of-sight TEC change and ROTI - index calculated on 5 min interval with 30 sec sampling rate (Pi et al, 1997). There are processed observations of more than 800 permanent stations which available from IGS, UNAVCO and EUREF networks. For analysis there is produced the daily map of the ROTI index as a function of geomagnetic local time on the grid with 2 deg x 2 deg resolution. The value in every cell is calculated by averaging of all ROTI values cover by cell area and it is proportional to the fluctuation event probability in the current sector. The ROTI maps, constructed by such way, allow to estimate the overall fluctuation activity and auroral oval evolutions. It is presented few case studies that illustrated ability of ROTI maps to represent changes of midlatitude, subauroral and auroral ionospheric structures during space weather events during the years of 2011-2013.

  15. A study of L band scintillations during the initial phase of rising solar activity at an Indian low latitude station

    NASA Astrophysics Data System (ADS)

    Tanna, H. J.; Karia, S. P.; Pathak, K. N.

    2013-08-01

    The ionospheric scintillation and TEC (Total Electron Content) variations are studied using GPS (Global Positioning System) measurements at an Indian low latitude station Surat (21.16°N, 72.78°E; Geomagnetic: 12.90°N, 147.35°E), situated near the northern crest of the equatorial anomaly region. The results are presented for data collected during the initial phase of current rising solar activity (low to moderate solar activity) period between January 2009 and December 2011. The results show that within a total number of 656 night-time scintillation events, 340 events are observed with TEC depletions, Rate of change of TEC (ROT) fluctuations and enhancement of Rate of change of TEC Index (ROTI). A comparison of night-time scintillation events from the considered period reveal strong correlation amongst the duration of scintillation activity in S4 index, TEC depletion, ROT fluctuations and ROTI enhancement in the year 2011, followed by the year 2010 and least in 2009. The statistical analyses of scintillation activity with enhancement of ROTI also show that about 70-96% scintillation activity took place in equinox and winter months. Moreover, from a nocturnal variation in occurrence of scintillation with (S4 ⩾ 0.2) and enhancement of ROTI with (ROTI ⩾ 0.5), a general trend of higher occurrence in pre-midnight hours of equinox and winter seasons is observed in both indices during the year 2011 and 2010, while no significant trend is observed in the year 2009. The results suggest the presence of F-region ionospheric irregularities with scale sizes of few kilometers and few hundred meters over Surat and are found to be influenced by solar and magnetic activity.

  16. Continuous generation and two-dimensional structure of equatorial plasma bubbles observed by high-density GPS receivers in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Buhari, S. M.; Abdullah, M.; Hasbi, A. M.; Otsuka, Y.; Yokoyama, T.; Nishioka, M.; Tsugawa, T.

    2014-12-01

    High-density GPS receivers located in Southeast Asia (SEA) were utilized to study the two-dimensional structure of ionospheric plasma irregularities in the equatorial region. The longitudinal and latitudinal variations of tens of kilometer-scale irregularities associated with equatorial plasma bubbles (EPBs) were investigated using two-dimensional maps of the rate of total electron content change index (ROTI) from 127 GPS receivers with an average spacing of about 50-100 km. The longitudinal variations of the two-dimensional maps of GPS ROTI measurement on 5 April 2011 revealed that 16 striations of EPBs were generated continuously around the passage of the solar terminator. The separation distance between the subsequent onset locations varied from 100 to 550 km with 10 min intervals. The lifetimes of the EPBs observed by GPS ROTI measurement were between 50 min and over 7 h. The EPBs propagated 440-3000 km toward the east with velocities of 83-162 m s-1. The longitudinal variations of EPBs by GPS ROTI keogram coincided with the depletions of 630 nm emission observed using the airglow imager. Six EPBs were observed by GPS ROTI along the meridian of Equatorial Atmosphere Radar (EAR), while only three EPBs were detected by the EAR. The high-density GPS receivers in SEA have an advantage of providing time continuous descriptions of latitudinal/longitudinal variations of EPBs with both high spatial resolution and broad geographical coverage. The spatial periodicity of the EPBs could be associated with a wavelength of the quasiperiodic structures on the bottomside of the F region which initiate the Rayleigh-Taylor instability.

  17. Monitoring and Modeling of Ionosphere Irregularities Caused By Space Weather Activity on the Base of GNSS Measurements

    NASA Astrophysics Data System (ADS)

    Cherniak, I.; Zakharenkova, I.; Krankowski, A.; Shagimuratov, I.

    2014-12-01

    The ionosphere plays an important role in GNSS applications because it influences on the radio wave propagation through out. The ionosphere delay is the biggest error source for satellite navigation systems, but it can be directly measured and mitigated with using dual frequency GNSS receivers. However GNSS signal fading due to electron density gradients and irregularities in the ionosphere can decrease the operational availability of navigation system. The intensity of such irregularities on high and mid latitudes essentially rises during space weather events. For monitoring of the ionospheric irregularities data collected from all available permanent GNSS stations in the Northern Hemisphere are processed and analyzed. Here we used parameters ROT (rate of GPS TEC change) and ROTI (index of ROT) to study the occurrence of TEC fluctuations. ROTI maps are constructed with the grid of 2 deg x 2 deg resolution as a function of the magnetic local time and corrected magnetic latitude. The ROTI maps allow to estimate the overall fluctuation activity and auroral oval evolutions, in general the ROTI values are corresponded to the probability of GPS signals phase fluctuations. There were developed several models in order to represent ionospheric fluctuations and scintillation activity under different geophysical conditions, but they were calibrated with data sets, that did not include GNSS derived data. It is very actual to develop empirical model based on GNSS derived measurements which can represent strong fluctuations of the ionosphere plasma density at high latitudes. The measurements provided by the existing permanent GNSS networks accumulated in order to develop the empirical model of ionospheric irregularities over the Northern hemisphere. As initial data the daily dependences of the ROTI index are used as a function of geomagnetic Local Time on the specific grid. With ROTI index maps it was determined the irregularities oval border and averaging parameter - semi

  18. Sensory acceptability of iron-fortified millet products.

    PubMed

    Tripathi, Bhumika; Ravi, R; Prakash, Maya; Platel, Kalpana

    2011-09-01

    Fortification of millet flours with iron might be beneficial in combating iron deficiency. In this investigation, two products prepared from finger millet and sorghum flours fortified with iron and ethylene diamine tetraacetic acid and stored for up to 60 days were evaluated for sensory quality attributes using quantitative descriptive analysis, and their texture was measured using a texture analyzer. Fortification did not cause any significant change in the hardness of dumpling or the shearing effect of the roti prepared from either of the millet flours. There was no significant effect of the fortificant on the texture and aroma of the products prepared from the fortified flours up to a period of 60 days. However, a discoloration was perceived in the dumplings prepared from the same flours. The overall quality of the roti prepared was acceptable to the sensory panelists. Finger millet and sorghum flours seem to be suitable as vehicles for fortification with iron. PMID:21568824

  19. Quantum chemical calculation (electronic and topologic) and experimental (FT-IR, FT-Raman and UV) analysis of isonicotinic acid N-oxide

    NASA Astrophysics Data System (ADS)

    Karaca, Caglar; Atac, Ahmet; Karabacak, Mehmet

    2015-04-01

    In this work, the molecular conformation, vibrational and electronic analysis of isonicotinic acid N-oxide (iso-NANO) were presented in the ground state using experimental techniques (FT-IR, FT-Raman and UV) and density functional theory (DFT) employing B3LYP exchange correlation with the 6-311++G(d,p) basis set. The geometry optimization and energies associated possible two conformers (Rot-I and Rot-II) were computed. The vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The obtained structures were analyzed with the Atoms in Molecules (AIMs) methodology. The computational results diagnose the most stable conformer of iso-NANO as the Rot-I form. Total density of state (TDOS) and partial density of state (PDOS) and also overlap population density of state (OPDOS) diagrams analysis for the most stable conformer (Rot-I) were calculated using the same method. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated. As a result, the optimized geometry and calculated spectroscopic data show a good agreement with the experimental results.

  20. Equatorial ionospheric irregularities using GPS TEC derived index

    NASA Astrophysics Data System (ADS)

    Oladipo, O. A.; Schüler, Torben

    2013-01-01

    We have used the rate of change of TEC (ROT) derived fluctuation index to study irregularities in the ionosphere at Franceville in Gabon (Lat.= -1.63°, Long.=13.55°, Geomag. Lat.= -0.71°), an equatorial station in the African sector. Based on a preliminary study at two equatorial stations at different longitude an average ROTI index which gives the fluctuation level over half an hour at a particular station was put forward. This index eliminates the noise spikes or extreme value usually present in ROTI index estimate. The new index ROTI was used to study ionospheric irregularity occurrence at Franceville. As far as we know, this is the first time irregularity occurrence study is being done at this station using GNSS data. The results obtained showed that ionospheric irregularity season at Franceville is from March to November and that there is a kind of minimum around June. Very low irregularities activity is also observed around January. Pre-midnight fluctuation is observed to be more pronounced at Franceville during the period studied.

  1. Studies on ionospheric scintillation using the S4 and ROT indices over Indian low latitude station during the year 2009 to 2012

    NASA Astrophysics Data System (ADS)

    Tanna, Hemali; Pathak, Kamlesh

    The dual frequency signals from the GPS satellites recorded at an Indian low latitude station Surat (21.16(°) N, 72.78(°) E), situated near the northern crest of the equatorial anomaly have been analysed to study the ionospheric scintillation in terms of amplitude scintillation S_{4} index and Total Electron Content (TEC) for the rising phase of solar activity period from the year 2009 to 2012. In this study we described the diurnal variation of scintillation along with TEC variation, solar activity dependence and effects of a space weather related event, a geomagnetic storms on scintillation. The diurnal variation of scintillation shows co-existence of F region irregularities with a scale length of few kilometers and 400 m as apparent from TEC depletion and ROT fluctuations, which occurred simultaneously during night-time ionospheric scintillation. The number of concurrently occurred scintillation activities with S _{4} _{}> 0.2 and enhancement of ROTI (ROTI>0.5) during different years are brought out. It is found that scintillation occurred with enhancement of ROTI at Surat is at its maximum during the year 2012, 2011 and 2010 followed by a minimum during the year 2009 showing positive correlation with solar activity. Scintillation variations during the geomagnetic storms registered during the period 2011-2012 with Dst <-100 nT are analysed. Scintillation inhibition and generation found the local time dependence of ring current strength measured by the Dst index showing good agreement with Aaron’s criteria.

  2. Quantum chemical calculation (electronic and topologic) and experimental (FT-IR, FT-Raman and UV) analysis of isonicotinic acid N-oxide.

    PubMed

    Karaca, Caglar; Atac, Ahmet; Karabacak, Mehmet

    2015-04-01

    In this work, the molecular conformation, vibrational and electronic analysis of isonicotinic acid N-oxide (iso-NANO) were presented in the ground state using experimental techniques (FT-IR, FT-Raman and UV) and density functional theory (DFT) employing B3LYP exchange correlation with the 6-311++G(d,p) basis set. The geometry optimization and energies associated possible two conformers (Rot-I and Rot-II) were computed. The vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The obtained structures were analyzed with the Atoms in Molecules (AIMs) methodology. The computational results diagnose the most stable conformer of iso-NANO as the Rot-I form. Total density of state (TDOS) and partial density of state (PDOS) and also overlap population density of state (OPDOS) diagrams analysis for the most stable conformer (Rot-I) were calculated using the same method. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated. As a result, the optimized geometry and calculated spectroscopic data show a good agreement with the experimental results. PMID:25589390

  3. Glycaemic index of selected staples commonly eaten in the Caribbean and the effects of boiling v. crushing.

    PubMed

    Ramdath, D Dan; Isaacs, Renée L C; Teelucksingh, Surujpal; Wolever, Thomas M S

    2004-06-01

    Integrating information about the glycaemic index (GI) of foods into the Caribbean diet is limited by the lack of data. Therefore, we determined the GI of eight staple foods eaten in the Caribbean and the effect on GI of crushing selected tubers. Groups of eight to ten healthy volunteers participated in three studies at two sites. GI was determined using a standard method with white bread and adjusted relative to glucose. The mean area under the glucose response curve elicited by white bread was similar for the different groups of subjects. In study 1, the GI of cassava (Manihot esculenta; 94 (sem 11)) was significantly higher than those of breadfruit (Artocarpus altilis; 60 (sem 9)), cooking 'green' banana (Musa spp.; 65 (sem 11)) and sadha roti (65 (sem 9)) (P=0.018). There was no significant difference in the GI of the foods in study 2: dasheen (Colocasia esculenta var. esculenta; 77 (sem 10)), eddoes (Colocasia esculenta var. antiquorum; 61 (sem 10)), Irish potato (Solanum tuberosum; 71 (sem 8)), tannia (Xanthosoma sagittifolium; 60 (sem 5)) and white yam (Dioscorea alata; 62 (sem 6)), and, in study 3, crushing did not significantly affect the GI of dasheen, tannia or Irish potato. However, when the results from studies 2 and 3 were pooled, the GI of dasheen (76 (sem 7)) was significantly greater than that of tannia (55 (sem 5); P=0.015) with potato being intermediate (69 (sem 6)). We conclude that dasheen and cassava are high-GI foods, whereas the other tubers studied and sadha roti are intermediate-GI foods. Given the regular usage of cassava and dasheen in Caribbean diets we speculate that these diets would tend to be high GI, although this could be reduced by foods such as sadha roti and white yam. The range of GI between the staples is sufficiently large that health benefits may be accrued by replacing high-GI staples with intermediate-GI staples in the Caribbean diet. PMID:15182400

  4. High-latitude ionospheric irregularities: differences between ground- and space-based GPS measurements during the 2015 St. Patrick's Day storm

    NASA Astrophysics Data System (ADS)

    Cherniak, Iurii; Zakharenkova, Irina

    2016-07-01

    We present an analysis of ionospheric irregularities at high latitudes during the 2015 St. Patrick's Day storm. Our study used measurements from ~2700 ground-based GPS stations and GPS receivers onboard five low earth orbit (LEO) satellites—Swarm A, B and C, GRACE and TerraSAR-X—that had close orbit altitudes of ~500 km, and the Swarm in situ plasma densities. An analysis of the rate of TEC index (ROTI) derived from LEO-GPS data, together with Swarm in situ plasma probe data, allowed us to examine the topside ionospheric irregularities and to compare them to the main ionospheric storm effects observed in ground-based GPS data. We observed strong ionospheric irregularities in the topside ionosphere during the storm's main phase that were associated with storm-enhanced density (SED) formation at mid-latitudes and further evolution of the SED plume to the polar tongue of ionization (TOI). Daily ROTI maps derived from ground-based and LEO-GPS measurements show the pattern of irregularities oriented in the local noon-midnight direction, which is a signature of SED/TOI development across the polar cap region. Analysis of the Swarm in situ plasma measurements revealed that, during the storm's main phase, all events with extremely enhanced plasma densities (>106 el/cm3) in the polar cap were observed in the Southern Hemisphere. When Swarm satellites crossed these enhancements, degradation of GPS performance was observed, with a sudden decrease in the number of GPS satellites tracked. Our findings indicate that polar patches and TOI structures in the topside ionosphere were predominantly observed in the Southern Hemisphere, which had much higher plasma densities than the Northern Hemisphere, where SED/TOI structures have already been reported earlier. LEO-GPS data (ROTI and topside TEC) were consistent with these results.

  5. Modelling of ionospheric irregularities during geomagnetic storms over African low latitude region

    NASA Astrophysics Data System (ADS)

    Mungufeni, Patrick

    2016-07-01

    In this study, empirical models of occurrence of ionospheric irregularities over low latitude African region during geomagnetic storms have been developed. The geomagnetic storms considered consisted of Dst ≤ -50 nT. GNSS-derived ionospheric Total Electron Content (TEC) data over Libreville, Gabon (NKLG) (0.35° N, 9.68° E, geographic, 8.05° S, magnetic) and Malindi, Kenya (MAL2) (2.99° S, 40.19° E, geographic, 12.42° S, magnetic) during 2000 - 2014 were used. Ionospheric irregularities at scale- lengths of a few kilometers and ˜400 m were represented with the rate of change of TEC index (ROTI). The inputs for the models are the local time, solar flux index, Auroral Electrojet index, day of the year, and the Dst index, while the output is the median ROTI during these given conditions. To develop the models, the ROTI index values were binned based on the input parameters and cubic B splines were then fitted to the binned data. Developed models using data over NKLG and MAL2 were validated with independent data over stations within 510 km and 680 km radius, respectively. The models captured the enhancements and inhibitions of the occurrence of the ionospheric irregularities during the storm period. The models even emulated these patterns in the various seasons, during medium and high solar activity conditions. The correlation coefficients for the validations were statistically significant and ranged from 0.58 - 0.73, while the percentage of the variance in the observed data explained by the modelled data ranged from 34 - 53.

  6. Geomagnetic storm effect on the occurrence of ionospheric irregularities over African equatorial sector using GPS-TEC

    NASA Astrophysics Data System (ADS)

    Amaechi, Paul; Oyeyemi, Elijah; Akala, Andrew

    2016-07-01

    Total electron content (TEC) derived from Global Navigation Satellite Systems (GNSS) measurements provided by the International GNSS Service (IGS) network have been used to study the occurrence of large scale ionospheric irregularities over the African equatorial sector. The rate of change of TEC (ROT) as well as its standard deviation over five minutes (ROTI) were used to monitor the level of irregularities over 3 stations distributed across the three longitudinal sectors of Africa (eastern, central and western longitudinal sectors). The storm effect on irregularities occurrence has been studied in conjunction with the disturbance storm time (Dst) and the z component of the Interplanetary magnetic field (IMFBz) indices during four intense storms which were classified according to their season of occurrence during the year 2015. Irregularities were associated with GPS-TEC fluctuations as seen in the increased ROT and ROTI values especially in the post sunset period. Irregularities were inhibited over all the stations during the storm of March plausibly as a result of electric field conditioned by the southward turning of IMFBz during the pre and post midnight periods. The triggering of irregularities over the western and central stations and their inhibition over the eastern station during the storm of June was controlled by the ring current. The storm effect on irregularities was not evident over the western and central stations but inhibition of irregularities was observed over the eastern station during the storm of September.

  7. The development of approaches for ionosphere irregularities modeling on the base of GNSS data

    NASA Astrophysics Data System (ADS)

    Cherniak, Iurii; Krankowski, Andrzej; Zakharenkova, Irina; Shagimuratov, Irk

    The ionosphere plays an important role in GNSS applications because it influences on the radio wave propagation through out. The ionosphere delay is the biggest error source for satellite navigation systems, but it can be directly measured and mitigated with using dual frequency GNSS receivers. However GNSS signal fading due to electron density gradients and irregularities in the ionosphere can decrease the operational availability of navigation system. There were developed several models in order to represent ionospheric fluctuations and scintillation activity under different geophysical conditions, but they were calibrated with data sets, that do not include GNSS derived data. It is very actual to develop empirical or semi-empirical model based on GNSS derived measurements which can represent strong ionosphere fluctuation events. In this work we use the data provided by the existing permanent GNSS network in order to produce information and products that can be used to investigate and formalize dependences of ionospheric fluctuation indices on the space weather conditions and to determine the background levels. Our investigation is based on the classical approach when Rate of TEC (ROT), detrended rate of line-of-sight TEC change and ROTI - indexes are calculated from GPS measurements. For analysis there are produced the daily dependences of the ROTI index as a function of geomagnetic local time on the variable grid and averaging parameters. The paper presents the statistical and correlation dependences between sets of geomagnetic indices and parameters that characterized the ionosphere irregularities activity for period of 2010 - 2013 years.

  8. Glycaemic and insulin responses of diabetic patients to traditional Malaysian meals and the effect of guar gum.

    PubMed

    Khalid, B A; Lee, L F; Samad, A H; Ng, M L

    1996-12-01

    The aims of the project were to determine the glycaemic and insulin responses of non-insulin dependent diabetic patients (NIDDM) to 3 traditional Malaysian meals compared to oral glucose, and to determine whether guar gum would affect these responses. Patients with NIDDM were tested with 75 g oral glucose and three common breakfast meals of the three main ethnic groups of Malaysia. When compared with the oral glucose group, significantly by lower blood glucose responses were seen at 90 and 120 minutes post prandial for nasi lemak (p<0.05) and at 60, 75 and 90 minutes for mee sup (p<0.05). No significant difference was seen for roti telur. There was no significant difference in plasma glucose at any time point of the study when the three test meals were compared with each other. Addition of 5g granulated guar gum mixed with water taken prior to the glucose significantly lowered the plasma glucose at 60, 120 and 150 minutes postprandially (p<0.05). Similarly for the test meals, guar gum significantly lowered plasma glucose concentration between 15 and 45 minutes (p<0.03) postprandial for nasi lemak and between 15 and 30 minutes (p<0.03) for mee sup but not with roti telur. With addition of guar gum, there was no significant change of insulin responses with the three meals but a significant increase was seen at 30 minutes (p<0.02) after ingestion of glucose. PMID:24394617

  9. Dispensing death, desiring death: an exploration of medical roles and patient motivation during the period of legalized euthanasia in Australia.

    PubMed

    Street, A; Kissane, D W

    A qualitative case study was conducted to explore the clinical decision making processes that underpinned the practice of euthanasia under the Rights of the Terminally Ill (ROTI) Act. The key informant for this research was Philip Nitschke, the general practitioner responsible for the legal cases of euthanasia. His information was supported by extensive document analysis based on the public texts created by patients in the form of letters and documentaries. Further collaborating sources were those texts generated by the media, rights groups, politicians, the coroner's cort, and the literature on euthanasia and assisted suicide. A key study finding was that the ROTI legislation did not adequately provide for the specific medical situation in the Northern Territory, Australia. The medical roles, as proscribed by the legislation, carried many inherent assumptions about the health care context and the availability of appropriately qualified medical staff committed to providing euthanasia. These assumptions translated into difficulties in establishing clinical practices for the provision of euthanasia. A further finding concerned the motivations of those who requested euthanasia. This article addresses the medical roles and the motivations of those seeking euthanasia. PMID:12578011

  10. Overview of the 2015 St. Patrick's day storm and its consequences for RTK and PPP positioning in Norway

    NASA Astrophysics Data System (ADS)

    Jacobsen, Knut Stanley; Linnea Andalsvik, Yngvild

    2016-02-01

    The 2015 St. Patrick's day storm was the first storm of solar cycle 24 to reach a level of "Severe" on the NOAA geomagnetic storm scale. The Norwegian Mapping Authority is operating a national real-time kinematic (RTK) positioning network and has in recent years developed software and services and deployed instrumentation to monitor space weather disturbances. Here, we report on our observations during this event. Strong GNSS (Global Navigation Satellite System) disturbances, measured by the rate-of-TEC index (ROTI), were observed at all latitudes in Norway on March 17th and early on March 18th. Late on the 18th, strong disturbances were only observed in northern parts of Norway. We study the ionospheric disturbances in relation to the auroral electrojet currents, showing that the most intense disturbances of GNSS signals occur on the poleward side of poleward-moving current regions. This indicates a possible connection to ionospheric polar cap plasma patches and/or particle precipitation caused by magnetic reconnection in the magnetosphere tail. We also study the impact of the disturbances on the network RTK and Precise Point Positioning (PPP) techniques. The vertical position errors increase rapidly with increasing ROTI for both techniques, but PPP is more precise than RTK at all disturbance levels.

  11. Modelling the probability of ionospheric irregularity occurrence over African low latitude region

    NASA Astrophysics Data System (ADS)

    Mungufeni, Patrick; Jurua, Edward; Bosco Habarulema, John; Anguma Katrini, Simon

    2015-06-01

    This study presents models of geomagnetically quiet time probability of occurrence of ionospheric irregularities over the African low latitude region. GNSS-derived ionospheric total electron content data from Mbarara, Uganda (0.60°S, 30.74°E, geographic, 10.22°S, magnetic) and Libreville, Gabon (0.35°N, 9.68°E, geographic, 8.05°S, magnetic) during the period 2001-2012 were used. First, we established the rate of change of total electron content index (ROTI) value associated with background ionospheric irregularity over the region. This was done by analysing GNSS carrier-phases at L-band frequencies L1 and L2 with the aim of identifying cycle slip events associated with ionospheric irregularities. We identified at both stations a total of 699 events of cycle slips. The corresponding median ROTI value at the epochs of the cycle slip events was 0.54 TECU/min. The probability of occurrence of ionospheric irregularities associated with ROTI ≥ 0.5 TECU / min was then modelled by fitting cubic B-splines to the data. The aspects the model captured included diurnal, seasonal, and solar flux dependence patterns of the probability of occurrence of ionospheric irregularities. The model developed over Mbarara was validated with data over Mt. Baker, Uganda (0.35°N, 29.90°E, geographic, 9.25°S, magnetic), Kigali, Rwanda (1.94°S, 30.09°E, geographic, 11.62°S, magnetic), and Kampala, Uganda (0.34°N, 32.60°E, geographic, 9.29°S, magnetic). For the period validated at Mt. Baker (approximately, 137.64 km, north west), Kigali (approximately, 162.42 km, south west), and Kampala (approximately, 237.61 km, north east) the percentages of the number of errors (difference between the observed and the modelled probability of occurrence of ionospheric irregularity) less than 0.05 are 97.3, 89.4, and 81.3, respectively.

  12. Investigation of ionospheric gradients for GAGAN application

    NASA Astrophysics Data System (ADS)

    Chandra, K. Ravi; Srinivas, V. Satya; Sarma, A. D.

    2009-05-01

    To cater to the needs of aviation applications, GPS Aided GEO Augmented Navigation (GAGAN) system is being implemented over the Indian region. The most prominent parameter affecting the navigation accuracy of GAGAN is ionospheric delay which is a function of TEC. In the equatorial and low latitude regions such as India, TEC is often quite high with large spatial gradients. Carrier phase data from the GAGAN network of Indian TEC Stations is used for estimating ionospheric gradients in multiple viewing directions. Rate of TEC (ROT) and Rate of TEC Index (ROTI) are calculated to identify the ionospheric gradients. Among the satellite signals arriving in multiple directions, the signals which suffer from severe ionospheric gradients are identified and avoided for improving GAGAN positional accuracy. The outcome of this paper will be helpful for improving GAGAN system performance.

  13. Maternal beliefs regarding diet during common childhood illnesses.

    PubMed

    Kapil, U; Sood, A K; Gaur, D R

    1990-06-01

    Maternal beliefs regarding diet during common childhood illnesses--diarrhea, fever, measles, cough and marasmus were determined in 143 rural mothers by using the interview technique. Some foods were preferred while others were restricted during episode of each illness, depending upon their 'hot' and 'cold', 'light' and 'heavy' and other characteristics, as determined by locally prevalent traditional dietary beliefs. 'Cold' foods like curd, butter milk were restricted during an episode of cough while 'hot' foods like tea, ginger with honey, were preferred. During diarrhea, 'light' foods like khichri, diluted milk and 'easy to digest' were preferred while 'heavy' foods like undiluted milk, roti and 'difficult to digest' were restricted. The study revealed that for a successful health education, it is important to identify local cultural practices and beliefs. The useful practices should be encouraged and reinforced while the harmful ones should be discouraged. PMID:2253996

  14. Maternal beliefs and practices regarding the diet and use of herbal medicines during measles and diarrhea in rural areas.

    PubMed

    Singh, M B

    1994-03-01

    Interviews with 208 mothers of children aged under 5 years were conducted in 21 villages of Jaipur District in Rajasthan State, India, to examine the dietary practices concerning food preferences and restrictions during measles and diarrheal disease. The researcher planned to use the findings to design nutrition education programs. 83.2% of the mothers were illiterate. 80% were of low or middle socioeconomic class. 66.4% worked in agriculture or animal husbandry. Preferred foods during diarrhea were khitchri (52.4%), thuli or daliya (48.5%), banana (37.9%), and chhach/curd (21.6%). Restricted foods included roti (69.7%), milk (47.1%), vegetables, chilies, and hot foods. The major herbal medicines used to cure diarrhea were isabgol ke bhusi mixed with curd (31.3%) and extracts of tea leaves, ajwain, sonth, peepla mul, black pepper, and tulsi leaves (14.4%). Preferred foods during measles were kishmish/munakka (38.5%), khitchri/rabdi of bajra (35.6%), daliya (25%), and cow's milk (23.1%). Restricted foods included roti (62.5%), all dals except moong dal (59.1%), and vegetables (42.8%). The leading herbal medicines used to treat measles were a mixture of nutmeg, mace, clove, tulsi leaves, and kishmish (26.9%) and a mixture of nutmeg, mace, clove, tulsi leaves, and brahmi (25.5%). The mothers believed that herbal medicines save their children's lives. These findings indicate the need to consider beliefs about culturally accepted and restricted foods when designing a nutritional and health education program. PMID:7896375

  15. Detection of the Equatorial Ionospheric Irregularities Using the POD GPS Measurements

    NASA Astrophysics Data System (ADS)

    Zakharenkova, I.; Astafyeva, E.; Cherniak, I.

    2015-12-01

    By making use of GPS measurements from Precise Orbit Determination (POD) GPS antenna onboard Low Earth Orbit (LEO) satellites we present results of the equatorial irregularities/plasma bubbles detection. For a given research we use data from a multi-satellite constellation consisting of the three Swarm satellites and the TerraSAR-X satellite. The major advantage of such LEO constellation is rather similar orbit altitude of ~500 km. The GPS-based indices, characterizing the occurrence and the strength of the ionospheric irregularities, were derived from the LEO GPS observations of a zenith-looking onboard GPS antenna. To study GPS fluctuation activity at the topside equatorial ionosphere we used TEC-based indices ROT (rate of TEC change) and ROTI (rate of TEC Index), proposed by Pi et al. (1997). We demonstrate a successful implementation of this technique for several case studies of the equatorial plasma bubbles occurrence in the post-midnight and morning LT hours during the year 2014. The ionospheric irregularities detected with GPS technique in Swarm/TerrasSAR-X data are consistent with the in situ plasma density variations registered by the three Swarm satellites (PLP measurements), as well as by three DMSP satellites at ~840 km orbital height, which indicate a large altitudinal extent of the observed phenomenon. Also we analyzed the global/seasonal distribution of the ionospheric irregularities at the topside equatorial region caused the phase fluctuations in GPS measurements onboard LEO satellite. We demonstrate that ROT/ROTI technique can be applied to LEO GPS data for geomagnetically quiet and disturbed conditions, as well as detection of the storm-induced equatorial irregularities in the morning local time.

  16. Signatures of solar event at middle and low latitudes in the Europe-African sector, during geomagnetic storms, October 2013

    NASA Astrophysics Data System (ADS)

    Azzouzi, I.; Migoya-Orué, Y.; Amory Mazaudier, C.; Fleury, R.; Radicella, S. M.; Touzani, A.

    2015-11-01

    This paper presents the variability of the total electron content, VTEC, the ROTI index (proxy of the scintillation index) and the transient variations of the Earth's magnetic field associated to the impacts of solar events during October 2013. The observations are from middle and low latitudes in European African longitude sector. During October 2013, there are four solar events reaching the Earth. The two first events, on October 2 and October 8 are CME, the third event on October 14, is a jet of fast solar wind flowing from a solar coronal hole, and the last event on October 30 is a slow solar wind with southward excursions of the Bz component of the interplanetary magnetic field, associated to CME passing near the Earth. For the four events, the variation of VTEC at middle latitudes is the same and presents an increase of VTEC at the time of the impact followed by a decrease of VTEC, lasting one or several days. At low latitudes, no clear common pattern for all the events appears. For the four events the variation of the ROTI index over Africa is different showing the asymmetry between West and East Africa. For the first event, on October 2, the scintillations are not inhibited, for the second and the fourth events on October 8 and 30, the scintillations are inhibited on East Africa and for the third event (high speed solar wind stream), on October 14, the scintillations are inhibited over the whole Africa. The available data allow the full explanation of the observations of October 14, indeed, on this day, there is no post sunset increase of the virtual height h‧F2 at Ascension Island. There is no Pre Reversal Enhancement (PRE) of the eastward electric field; it is this electric field which moves up the F layer, the necessary condition for the existence of scintillation. The analysis of the variations of the Earth's magnetic field at low latitudes highlights the presence of the ionospheric disturbance dynamo on October 14, which produces a decrease of the

  17. Investigation of the Ionospheric Fluctuations Caused by Space Weather Effects Using GNSS TEC Measurements

    NASA Astrophysics Data System (ADS)

    Shagimuratov, Irk; Krankowski, Andrzej; Cherniak, Iurii; Ephishov, Ivan; Zakharenkova, Irina; Yakimova, Galina

    2013-04-01

    It is known that GPS radio signals passing through the ionosphere suffer varying degrees of rapid variations of their amplitude and phase - signal scintillations. The scintillations are caused by the presence of wide range of scale size irregularities in the ionosphere. It is very important to estimate scintillation and phase fluctuation effects on GNSS navigation system (GPS/GLONASS) performance and consequently on the precession of the obtained position. Effects of the ionospheric irregularities on the GPS signals can be evaluated by measurements of the differential phase time rate of dual frequency GPS signals. GPS observations carried out at the Arctic IGS (International GNSS Service) stations were used to study the development of TEC fluctuations in the high latitude ionosphere. Standard GPS measurements with 30s sampling rate allow the detection of middle- and large-scale ionospheric irregularities. For detection of ionospheric fluctuations the rate of TEC (ROT, in the unit of TECU/min) at 1 min interval was used. The temporal occurrence of TEC fluctuations is clearly observed in time variations in the dual frequency carrier phase along satellite passes. As a measure of the fluctuation activity level the Rate of TEC Index (ROTI) based on standard deviation of ROT was also used. ROTI was estimated in 10-minute interval. These techniques and IGS data were used to study the occurrence of TEC fluctuations at the northern latitude ionosphere for selected geomagnetic storms occurred at the end of 23rd and beginning of new 24th solar cycles. Results demonstrate that fluctuation activity of GPS signals in the high latitude ionosphere is depended on geomagnetic conditions. Intensity of fluctuations essentially increases during geomagnetic storms. The strongest TEC fluctuations occurred as short time rate of TEC enhancements of a factor of 2-5 relative to the quiet time. During geomagnetic disturbed conditions strong phase fluctuations can register at latitudes low

  18. Storage influence on the functional, sensory and keeping quality of quality protein maize flour.

    PubMed

    Shobha, D; Kumar, H V Dileep; Sreeramasetty, T A; Puttaramanaik; Gowda, K T Pandurange; Shivakumar, G B

    2014-11-01

    Apart from nutritional values functional and sensory properties affect the behavior of food system and its acceptability for consumption during storage. Hence keeping quality of maize flour (HQPM-7) with and without lime treatment(control) was studied in terms of functional (bulk density, pH, swelling capacity, water and oil absorption capacity, least gelation concentration, peroxide value), sensory (appearance, color, taste, texture, mouth feel and overall acceptability) and rolling parameters (water absorption by flour, rolling quality, diameter after baking ) for a period of 6 months under room temperature (25 ± 5 °C) in two types of packages viz, LDPE cover (P) and plastic box (B). Physical parameters such as length, breadth and thickness (11.26-10.52 mm, 9.67-9.14 mm, & 4.72-3.95 mm) were reduced in lime treated grains compared to control. Significant increase (p ≤ 0.05) in ash content of lime treated flour (1.67 ± 0.01 g) was observed compared to control (1.5 ± 0.02 g). Calcium content of lime treated maize flour increased significantly (p ≤ 0.05) from 48 to 136 mg. There is a significant reduction in functional properties of flour after 3 and 2 months irrespective in polyethylene cover and plastic box. The properties like rolling quality, diameter after baking and water uptake by the flour were reduced significantly (p ≤ 0.05) after 4 months of storage in treated and after 1 month in control samples. Sensory scores of roti (dry pan cake) decreased significantly after 3 months of storage with an overall acceptability score of 4.0 and 3.4. In control samples mean taste (3.6), mouth feel (3.8) as well as OAA scores (3.8) decreased after second month. Hence lime treated maize flour with added nutritional benefits is suitable for making rotis of good palatability and can be stored in LDPE covers up to 3 months. PMID:26396307

  19. Importance of Ionospheric Gradients for error Correction

    NASA Astrophysics Data System (ADS)

    Ravula, Ramprasad

    Importance of Ionospheric Gradients for error Correction R. Ram Prasad1, P.Nagasekhar2 1Sai Spurthi Institute of Technology-JNTU Hyderabad,2Sai Spurthi Institute of Technology-JNTU Hyderabad Email ID:rams.ravula@gmail.com In India, Indian Space Research Organization (ISRO) has established with an objective to develop space technology and its application to various national tasks. To cater to the needs of civil aviation applications, GPS Aided Geo Augmented Navigation (GAGAN) system is being jointly implemented along with Airports Authority of India (AAI) over the Indian region. The most predominant parameter affecting the navigation accuracy of GAGAN is ionospheric delay which is a function of total number of electrons present in one square meter cylindrical cross sectional area in the line of site direction between the satellite and the user on the earth i.e. Total Electron Content (TEC).The irregular distribution of electron densities i.e. rate of TEC variation, causes Ionospheric gradients such as spatial gradients (Expressed in TECu/km) and temporal gradients (Expressed in TECu /minute). Among the satellite signals arriving to the earth in multiple directions, the signals which suffer from severe ionospheric gradients can be estimated i.e. Rate of TEC Index (ROTI) and Rate of TEC (ROT). These aspects which contribute to errors can be treated for improving GAGAN positional accuracy.

  20. Re-examination of Hemidactylus tenkatei van Lidth de Jeude, 1895: Populations from Timor provide insight into the taxonomy of the H. brookii Gray, 1845 complex (Squamata: Gekkonidae).

    PubMed

    Kathriner, Andrew; O'shea, Mark; Kaiser, Hinrich

    2014-01-01

    Recent herpetofaunal investigations in Timor-Leste revealed populations similar to Hemidactylus brookii Gray, 1845 in four of 13 districts. In order to properly identify these populations, we examined their relationships to other H. brookii-complex populations, notably those from nearby Roti Island, Indonesia (to which the name H. tenkatei van Lidth de Jeude, 1895 has been applied) and topotypic Bornean samples. We evaluated both meristic and mensural data from a set of specimens that included the type material of H. brookii and H. tenkatei, and we generated nuclear (RAG1) and mitochondrial (ND2) DNA sequence data for Timor-Leste specimens and a topotypical Bornean specimen presumed to represent H. brookii sensu stricto. Morphologically, Timorese geckos are clearly distinct from H. brookii and identical to H. tenkatei. Our molecular data show that the Bornean specimen thought to be H. brookii is genetically congruent with Timor-Leste specimens, and this specimen is therefore identified as H. tenkatei. Our data also reveal that the Burmese species H. subtriedroides Annandale, 1905 is distinct from both H. tenkatei and H. brookii. While the current data do not allow us to determine with certainty whether H. tenkatei is the oldest available name for these widespread forms, it is the only name that can be reliably applied at this time. PMID:25543951

  1. Wheat-based traditional flat breads of India.

    PubMed

    Parimala, K R; Sudha, M L

    2015-01-01

    Wheat forms the basic ingredient for various bakery and traditional products. Wheat-based flat breads are one of the traditional products prepared in different parts of the world. Different regions of the world have inherited different preparation methods since time immemorial, which has led to the existence of traditional flat breads'. Being traditional, only a few have been extensively studied scientifically. India, being the second largest producer of wheat, has a great saga of traditional flat breads with different tastes and texture. This review is a compiled information related to the research studies carried out on some of the wheat-based traditional flat breads of India namely chapati, puri, tandoori roti, parantha (whole-wheat flour based) and parotta, naan, bhatura, kulcha (refined wheat flour based) which indicates the magnitude of attention they have drawn among the food scientists. The review delves upon the developments and improvements brought about in the storage stability and realization of large-scale production of few of these flat breads which has helped considerably to cater to the growing demand in the domestic as well as international markets. The review also indicates the possibility and the tremendous scope available for technological developments for traditional flat breads. PMID:24915406

  2. GPS and in situ Swarm observations of the equatorial plasma density irregularities in the topside ionosphere

    NASA Astrophysics Data System (ADS)

    Zakharenkova, Irina; Astafyeva, Elvira; Cherniak, Iurii

    2016-07-01

    Here we study the global distribution of the plasma density irregularities in the topside ionosphere by using the concurrent GPS and Langmuir probe measurements onboard the Swarm satellites. We analyze 18 months (from August 2014 till January 2016) of data from Swarm A and B satellites that flew at 460 and 510 km altitude, respectively. To identify the occurrence of the ionospheric irregularities, we have analyzed behavior of two indices ROTI and RODI based on the change rate of total electron content and electron density, respectively. The obtained results demonstrate a high degree of similarities in the occurrence pattern of the seasonal and longitudinal distribution of the topside ionospheric irregularities derived from both types of the satellite observations. Among the seasons with good data coverage, the maximal occurrence rates for the post-sunset equatorial irregularities reached 35-50 % for the September 2014 and March 2015 equinoxes and only 10-15 % for the June 2015 solstice. For the equinox seasons the intense plasma density irregularities were more frequently observed in the Atlantic sector, for the December solstice in the South American-Atlantic sector. The highest occurrence rates for the post-midnight irregularities were observed in African longitudinal sector during the September 2014 equinox and June 2015 solstice. The observed differences in SWA and SWB results could be explained by the longitude/LT separation between satellites, as SWB crossed the same post-sunset sector increasingly later than the SWA did.

  3. The Mapping of high-latitude TEC fluctuations during the last extended solar minimum

    NASA Astrophysics Data System (ADS)

    Sieradzki, R.; Cherniak, I.

    2012-04-01

    During the last few years the number of the GPS permanent stations have been increasing systematically. Currently it is possible to use phase GPS observations for detecting of the ionospheric disturbances with high spatial and temporal resolution. In this study 30 second GPS measurements were used to investigate the occureance of the TEC fluctuations at high and mid latitudes during the extended solar minimum period (2008-2011). Based on observations from more than 100 permanent stations the 2-hour maps of the TEC variability and daily map of the ionospheric fluctuations as a function geomagnetic local time were created. In order to determine the variability of the ionosphere ROT (Rate of TEC) and ROTI (Rate of TEC index) were used. The diurnal, seasonal, and storm-time variations of TEC fluctuation activity were estimated. The most intensive TEC fluctuations at considered period were observed during several weak and moderate geomagnetic disturbances at November 2008, July 2009 and May 2010. The statistical characteristics of fluctuation intensity and TEC fluctuations maps as well as data processing technique are presented.

  4. Investigation of ionospheric scintillation at UKM station, Malaysia during low solar activity

    NASA Astrophysics Data System (ADS)

    Seif, Aramesh; Abdullah, Mardina; Marie Hasbi, Alina; Zou, Yuhua

    2012-12-01

    In this paper the investigation of the occurrence of ionospheric scintillation with S4≥0.2 was conducted by using a dual-frequency GISTM (GPS Ionospheric Scintillation and TEC monitor) at Universiti Kebangsaan Malaysia station, Malaysia (2.55°N, 101.46°E; geomagnetic: 7.39°S, 173.63°E) between September 2009 and December 2010. The study shows that significant nighttime amplitude scintillation event with 0.4≤S4<0.6 mainly occurred in the months of March, September and October, while significant daytime amplitude scintillation activity took place in November and December with 0.3≤S4<0.5. Moreover, nighttime amplitude scintillation observed at UKM station always occurred with phase scintillations, total electron content (TEC) depletions, rate of change of TEC (ROT) fluctuations and the enhancement of rate of TEC index (ROTI). Nevertheless, during daytime amplitude scintillation, TEC depletions and ROT fluctuations were much weaker than those that occurred during nighttime and this may be caused by small scale irregularities in the E region, called sporadic-E (Es), while the occurrences of nighttime amplitude scintillation maybe caused by the ionospheric irregularities in the F region.

  5. The occurrence of polar cap patches in TEC fluctuations detected using GPS measurements in southern hemisphere

    NASA Astrophysics Data System (ADS)

    Krankowski, A.; Shagimuratov, I. I.; Baran, L. W.; Ephishov, I. I.; Tepenitzyna, N. J.

    2006-01-01

    GPS technique is widely used to study the global structure and dynamics of the ionosphere. This paper presents data on the occurrence of large-scale ionospheric irregularities observed at Antarctic stations McMurdo-MCM4 (-78N, 167E, Φ = 80°), Casey-CAS1 (-66N, 110E, Φ = 80°), Mawson-MAW1 (-68N, 63E, Φ = 71°), and Davis-DAV1 (-69N, 78E, Φ = 75°) in 2001. The irregularities caused strong Total Electron Content fluctuations. The intensity of TEC fluctuations was estimated with the ROT parameter and rate of TEC index (ROTI) expressed in TECU/min. Storm-time development of TEC fluctuations are presented for two geomagnetic active periods: June and September 2001. Data on temporal variations in TEC along individual satellites passes were also analyzed. Polar patches were associated with deep TEC fluctuations as the TEC enhancements were 2 10 times larger than the background, whereas the TEC increased by 10 50 TECU in about 5 10 min. The duration of such structures is 10 20 min. At 4 5 h interval, 3 5 strong and some weak patches were detected. The activity of patches depends to a low degree only on the magnetic activity index Kp. The intensity of TEC fluctuations increases during substorm activity. Diurnal, seasonal dependence, and longitudinal features of the occurrence of polar patches are also presented in the report.

  6. High latitude TEC fluctuations and irregularity oval during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Shagimuratov, I. I.; Krankowski, A.; Ephishov, I.; Cherniak, Yu.; Wielgosz, P.; Zakharenkova, I.

    2012-06-01

    GPS measurements obtained by the global IGS network were used to study the occurrence of TEC fluctuations in the northern and southern high-latitude ionosphere during severe geomagnetic storms. In the northern hemisphere, GPS stations located higher than 55N Corrected Geomagnetic Latitude (CGL) at different longitudes were selected. In the southern hemisphere, Antarctic permanent GPS stations were used. Dual-frequency GPS measurements for individual satellite passes served as raw data. As a measure of fluctuation activity the rate of TEC (ROT) was used, and the fluctuation intensity was evaluated using the ROTI index. Using daily GPS measurements from all selected stations, images of the spatial and temporal behavior of TEC fluctuations were formed (in Corrected Geomagnetic Coordinates—CGC and geomagnetic local time—GLT). Similarly to the auroral oval, these images demonstrate an irregularity oval. The occurrence of the irregularity oval relates to the auroral oval, cusp and polar cap. During a storm, the intensity of TEC fluctuations essentially increased. The irregularity oval expands equatorward with an increase of magnetic activity. The study showed that the existing high-latitude GPS stations can provide a permanent monitoring tool for the irregularity oval in near real-time. In this paper, the features of the development of phase fluctuations at the geomagnetic conjugate points, and inter-hemispheric differences and similarities during winter and summer conditions, are discussed.

  7. Monitoring of free glutamic acid in Malaysian processed foods, dishes and condiments.

    PubMed

    Khairunnisak, M; Azizah, A H; Jinap, S; Nurul Izzah, A

    2009-04-01

    A study to quantify the free glutamic acid content of six processed foods, 44 dishes and 26 condiments available in Malaysia was performed using high-performance liquid chromatography with a fluorescence detector (HPLC-FRD). Recovery tests were carried out with spiked samples at levels from 6 to 31 mg g(-1). High recovery in different matrices was achieved ranging from 88% +/- 13% to 102% +/- 5.12%, with an average of 97% +/- 8.92%. Results from the study revealed that the average free glutamic acid content ranged from 0.34 +/- 0.20 to 4.63 +/- 0.41 mg g(-1) in processed foods, while in prepared dishes it was as low as 0.24 +/- 0.15 mg g(-1) in roti canai (puffed bread served with curry or dhal) to 8.16 +/- 1.99 mg g(-1) in dim sum (a small casing of dough, usually filled with minced meat, seafood, and vegetables, either steamed or fried). Relatively, the content of free glutamic acid was found to be higher in condiments at 0.28 +/- 0 mg g(-1) in mayonnaise to 170.90 +/- 6.40 mg g(-1) in chicken stock powder. PMID:19680916

  8. Heroic frames: discursive constructions around the requested death movement in Australia in the late-1990s.

    PubMed

    McInerney, Fran

    2006-02-01

    This paper focuses on a critical development in the life of the requested death movement [McInerney, F. (2000). "Requested Death": A new social movement. Social Science & Medicine, 50(1), 137-54.], that being the passage of the Northern Territory of Australia's Rights of the Terminally Ill (ROTI) Act 1995. This legislation, for the first time anywhere in the world, allowed for lawful euthanasia and physician-assisted suicide, thereby fulfilling key requirements of the movement. Taking a constructionist perspective, I analyzed discursive representations of dying, death and medicine in selected Australian print media during this time period (1995-1997). The media's predilection for reporting dramatic and unusual death coincided with the movement's construction of contemporary dying as horrific, intractable, and intolerable. Across all analyzed publications and genres, an heroic discourse was found to be a dominant influence, couched within a dramatic framing that served to reinforce many of the claims of the requested death movement. The framing of requested death activists as heroes, and of requested death itself as a redeeming and transforming act for those seeking it, were preeminent in press portrayals. The dominance of this heroic discourse suggests that such media and movement frames worked in tandem to both resonate with and reinforce popular Australian notions of terminal illness and dying in the late 20th century. PMID:16046040

  9. High-resolution total electron content observations of severe ionospheric disturbances using dense GPS receiver networks

    NASA Astrophysics Data System (ADS)

    Tsugawa, Takuya; Kato, Hisao; Kubota, Minoru; Hidekatsu, Jin; Maruyama, Takashi; Nagatsuma, Tsutomu; Saito, Akinori; Nishioka, Michi; Otsuka, Yuichi; Miyake, Wataru; Supnithi, Pornchai; Kenpankho, Prasert

    Two-dimensional total electron content (TEC) maps have been derived from ground-based GPS receiver networks and applied to studies of various ionospheric disturbances since mid-1990s. For the purpose of monitoring and researching ionospheric disturbances which can degrade GNSS navigations and cause loss-of-lock on GNSS signals, National Institute of Information and Communications Technology (NICT), Japan has developed TEC maps over Japan using the dense GPS network, GEONET, which consists of more than 1,200 GPS receivers and is operated by Geophysical Survey Institute, Japan. Currently, we are providing two-dimensional maps of absolute TEC, detrended TEC with 60, 30, 15-minute window, rate of TEC change index (ROTI), and loss-of-lock on GPS signal over Japan. These data and quick-look maps since 1997 are archived and available in the website of NICT (http://wdc.nict.go.jp/IONO/). Recently developed GPS receiver networks in North America and Europe make it possible to obtain regional TEC maps with higher spatial and temporal resolution than the global weighted mean TEC maps in the IONEX format provided by several institutes such as International GNSS Service (IGS) and another global TEC map provided by MIT Haystack observatory. Recently, we have also developed the regional TEC maps over North America and Europe. These data and quick-look maps are also available in the NICT website. In this presentation, we will show some severe ionospheric events such as high latitude storm-time plasma bubbles and storm enhanced density events observed over Japan using the GPS-TEC database. These events cause loss-of-lock of GPS signals and large GPS positioning errors. We will also introduce some interesting ionospheric events over Europe and North America, and discuss about a future direction of our GPS-TEC data service.

  10. A statistical study of GPS loss of lock caused by ionospheric disturbances

    NASA Astrophysics Data System (ADS)

    Tsugawa, T.; Nishioka, M.; Otsuka, Y.; Saito, A.; Kato, H.; Kubota, M.; Nagatsuma, T.; Murata, K. T.

    2010-12-01

    Two-dimensional total electron content (TEC) maps have been derived from ground-based GPS receiver networks and applied to studies of various ionospheric disturbances since mid-1990s. For the purpose of monitoring and researching ionospheric disturbances which can degrade GNSS navigations and cause loss-of-lock on GNSS signals, National Institute of Information and Communications Technology (NICT), Japan has developed TEC maps over Japan using the dense GPS network, GEONET, which consists of more than 1,200 GPS receivers and is operated by Geophysical Survey Institute, Japan. Currently, we are providing two-dimensional maps of absolute TEC, detrended TEC with 60, 30, 15-minute window, rate of TEC change index (ROTI), and loss-of-lock (LOL) on GPS signal over Japan. These data and quick-look maps since 1997 are archived and available in the website of NICT (http://wdc.nict.go.jp/IONO/). Recently developed GPS receiver networks in North America and Europe make it possible to obtain regional TEC maps with higher spatial and temporal resolution than the global weighted mean TEC maps in the IONEX format provided by several institutes such as International GNSS Service (IGS) and another global TEC map provided by MIT Haystack observatory. Recently, we have also developed the regional TEC maps over North America and Europe. These data and quick-look maps are also available in the NICT website. In this presentation, we will show some severe ionospheric events such as high latitude storm-time plasma bubbles and storm enhanced density events observed over Japan using the GPS-TEC database. These events cause loss-of-lock of GPS signals and large GPS positioning errors. We also discuss about the statistical characteristics of LOL on the GPS signal caused by ionospheric disturbances.

  11. Knowledge, attitudes and practice regarding infant feeding among mother substitutes.

    PubMed

    Jethi, S C; Shrivastava, D K

    1987-10-01

    With more women entering the workforce, the issue of infant nutrition has become more complex. Mother surrogates, or substitutes, are increasingly taking over the responsibility of infant care. 80 mother substitutes, aged 7-70, were interviewed in Jabalpur town, India, from October 1983-July 1984. Substitutes originated from nuclear families consisting of grandmothers, aunts, elder sisters, brothers, and servants. They were questioned concerning breast feeding, top milk initiation, feeding technique, and weaning. Results pointed to a variety of opinions on feeding practices and nutrition. 50% of younger mother substitutes and the majority of older, uneducated ones believed in initiating breast feeding from the 2nd day onward. 50% of young and 64% of older substitutes did not consider giving colostrum, and various reasons why are cited. 20% of all and 42% of highly educated substitutes were aware of the advantages of breast feeding. 65% of young and 60% uneducated did not know age of initiation of top milk. 45% advocated bottle feeding, with 25% preferring spoon feeding. With regard to "tinned milk" 40% did not use it, 25% were unaware of it, and of 30% using tinned milk, only 1/3 knew the correct technique of reconstitution. The majority of young and uneducated substitutes thought proper weaning age to be after 6 months. 50%, aged 21-40 years, believed in adding solid food from below 6 months. 90% of the young mother substitutes were against solids being introduced by the age of 4 months. A majority of the substitutes suggested weaning foods such as dal, rice, roti, and biscuits with a few considering tinned cereals as proper weaning foods. This response may point to the reason why protein and energy deficiency may be observed around weaning age in many infants throughout the 3rd world. PMID:3448014

  12. Observational study of ionospheric irregularities and GPS scintillations associated with the 2012 tropical cyclone Tembin passing Hong Kong

    NASA Astrophysics Data System (ADS)

    Yang, Zhe; Liu, Zhizhao

    2016-05-01

    This study presents the ionospheric responses observed in Hong Kong to a Typhoon, namely, Tembin, from the aspects of the occurrence of ionospheric irregularities and scintillations, using Global Positioning System (GPS) observations from a ground-based GPS scintillation monitoring station in Hong Kong and from GPS receivers on board the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. The ionospheric irregularities and scintillations are characterized by the rate of total electron content variation index (ROTI) and the amplitude scintillation index S4, respectively. The typhoon Tembin formed over the western North Pacific during 18-30 August 2012 and approached Hong Kong during 24-27 August 2012 with the closest distance 290 km from Hong Kong at around 17 universal time (UT) on 25 August 2012. The ground-based observations indicate that in the nighttime period of 20:00-02:00 local time (LT = UT + 8 h) on 26 August when Tembin passed closely to Hong Kong, the ionospheric irregularities and scintillations of GPS signals were observed in the south of Hong Kong, over the area of 13°N ~ 23°N in latitude and 110°E ~ 120°E in longitude. From the COSMIC observations, it shows that the number of radio occultation scintillation events peaks on 26 August 2012 during the passage of Tembin. Without the presence of strong geomagnetic or solar activity, it is suspected that gravity waves might be generated in the lower atmosphere and likely seed the formation of ionospheric plasma irregularities. This work for the first time from Hong Kong observes the sign of coupling between the lower atmosphere and ionosphere in a tropical cyclone event, combining both ground- and space-based GPS observation data.

  13. Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong

    NASA Astrophysics Data System (ADS)

    Zhu, Wu; Ding, Xiao-Li; Jung, Hyung-Sup; Zhang, Qin; Zhang, Bo-Chen; Qu, Wei

    2016-08-01

    Synthetic Aperture Radar Interferometry (InSAR) has demonstrated its potential for high-density spatial mapping of ground displacement associated with earthquakes, volcanoes, and other geologic processes. However, this technique may be affected by the ionosphere, which can result in the distortions of Synthetic Aperture Radar (SAR) images, phases, and polarization. Moreover, ionospheric effect has become and is becoming further significant with the increasing interest in low-frequency SAR systems, limiting the further development of InSAR technique. Although some research has been carried out, thorough analysis of ionospheric influence on true SAR imagery is still limited. Based on this background, this study performs a thorough investigation of ionospheric effect on InSAR through processing L-band ALOS-1/PALSAR-1 images and dual-frequency Global Positioning System (GPS) data over Hong Kong, where the phenomenon of ionospheric irregularities often occurs. The result shows that the small-scale ionospheric irregularities can cause the azimuth pixel shifts and phase advance errors on interferograms. Meanwhile, it is found that these two effects result in the stripe-shaped features in InSAR images. The direction of the stripe-shaped effects keep approximately constant in space for our InSAR dataset. Moreover, the GPS-derived rate of total electron content change index (ROTI), an index to reflect the level of ionospheric disturbances, may be a useful indicator for predicting the ionospheric effect for SAR images. This finding can help us evaluate the quality of SAR images when considering the ionospheric effect.

  14. Probing high latitude ionospheric irregularities by GPS: Results and analysis

    NASA Astrophysics Data System (ADS)

    Krankowski, Andrzej; Shagimuratov, Irk; Ephishov, I. I.; Sieradzki, Rafal

    The GPS measurements of IGS network were used to study the occurrence of TEC fluctuations at northern and southern high latitude ionosphere during severe geomagnetic disturbances of 22-28 July 2004. For the northern hemisphere we selected 20 GPS stations located higher than 55 degrees of Corrected Geomagnetic Latitude. For the southern hemisphere, Antarctic permanent GPS stations were used. Dual-frequency GPS measurements along individual satellite passes served as row data. As a measure a fluctuation activity the rate of TEC (ROT) was used, and fluctuation intensity was evaluated using ROTI index. Using daily GPS measurements from all the selected stations, the images of spatial and temporal behavior of TEC fluctuations (in Corrected Geomagnetic Coordinate and local geomagnetic time) were formed. Similarly to the auroral oval the images demonstrate an irregularities oval. The occurrence of irregularities oval relates with the auroral oval and polar caps. During the storm, TEC fluctuation activity and intensity essentially increased. The irregularities oval expands equatorward with increasing magnetic activity. As a whole, the dynamics of the irregularities ovals in both hemispheres are similar during the storm time, however we found some difference in development of TEC fluctuations between northern and southern ionosphere. They may be caused by seasonal features of excitation of irregularities at high latitude ionosphere. Daily pattern of the irregularities oval was controlled by the motion of the station location into auroral oval. Maximal intensity of TEC fluctuations took place over polar stations. The strong TEC fluctuations were associated with the polar patches. Their study showed that the existing high-latitude GPS stations can provide a permanent monitoring of the irregularities oval in near real-time.

  15. Estimation of parameters to monitor state of the ionosphere in a single station mode

    NASA Astrophysics Data System (ADS)

    Cokrlic, M.; Galas, R.

    2013-12-01

    Ionosphere is the dispersive medium and propagation of the electromagnetic waves depend on its frequency. In the Global Positioning System (GPS), after the Selected Availability (SA) has been turned off, ionospheric delay become one of the largest source of error. Relatively low cost of the GPS receivers makes it one of the cheapest tool for studying and monitoring of the ionosphere in a global scale. Especially because the GPS signals are carrying ionospheric characteristics that can be isolated and then studied. For real time applications, demanding high accuracy and availability, it is important to know variable, in time and space, state of the ionosphere in real-time. Ionospheric perturbations can degrade accuracy of the positioning for more than hundred meters and even make positioning impossible or false. Thus, information about state of the ionosphere must be available in real time to enhance availability and to improve navigation accuracy. The state of the ionosphere can be characterized by a couple of basic parameters such as: Total Electron Content (TEC), Rate of TEC (ROT), Rate of change of TEC (ROTI), amplitude scintillation (S4) and phase scintillation (σ_φ). This parameters can be estimated form GPS networks or from a single GPS station. We are developing software tools to measure those parameters in a very challenging single station mode. Some of the modules, like e.g. calculation of S4 and ROT, are validated and some others are still in the testing phase. The tools are needed in order to analyze ionospheric perturbation parameters in real- or near- real time and investigate if some new approaches for generation of corrections can be developed. Our main goal is provision of such corrections, or at least warnings about ionospheric perturbations, to single station PPP (Precise Point Positioning) users. In the poster the algorithms are described and preliminary results are presented.

  16. The glycemic index (GI) and glycemic load (GL) of five commonly consumed foods of the South Pacific.

    PubMed

    Lako, Jimaima; Sotheeswaran, Subramania; Aalbersberg, William; Sreekumar, K P

    2004-03-01

    Glycemic index (GI) has been widely used in the management of blood sugar levels among diabetes however; in the South Pacific very little information regarding the GI of local foods is made available. The objectives of this research were to determine the glycemic index and the glycemic load of 5 South Pacific foods, which have not been studied. The foods tested were plantain (Musa AAB), tannia (Xanthosoma sagittifolium), roti or chappati, homemade pancake and Lees cabin crackers. Glucose powder mixed in 200 mL of water was used as reference food. Eight apparently healthy indigenous Fijian males from the Fiji Military Forces aged 25-36 years old were recruited for this study. Participants were given a 50 g carbohydrate portion of the test foods to ingest after a 10-12 hour fast the night before the test and the standard reference food were administered to participants on different days for comparison. In the morning, capillary blood samples were drawn from the fingers at 0 min, 15, 30, 45, 60, 90 and 120 minutes postprandially and the blood glucose level was determined. The equation of Wolever using computer software was used to calculate the glycemic index and the glycemic load was calculated using the formular provided in the Harvard Health Online. The results showed that individuals respond to foods differently thus affecting the GI average values. The glycemic index has been categorized by Miller as low GI is pounds 55, moderate GI is between 56-69 and high GI is > or = 70. All the five carbohydrate foods understudy have moderate GI values ranging from 59 to 68. The Glycemic Load (GL) for cabin biscuit was the highest. PMID:18181442

  17. Acute effects of acarbose on post-prandial glucose and triglycerides in type 2 diabetics following intake of different Malaysian foods.

    PubMed

    Nawawi, H M; Yazid, T N; Ismail, F; Khalid, B A

    2000-03-01

    Acarbose inhibits intestinal alpha-glucosidases resulting in diminished and delayed postprandial hyperglycaemia (PPH). Studies on effects of acarbose on postprandial lipaemia (PPL) have been inconclusive. Little is known about the effects of acarbose on PPH and PPL following intake of a polysaccharide diet. We studied 30 type 2 diabetic patients on dietary and/or oral hypoglycaemic agent(s). Thirty patients were recruited for food A (nasi lemak), 28 for food B (mee goreng) and 28 for food C (roti telur), which represent the typical diets of the three main races in Malaysia. Serial blood samples were taken at 15 min before and up to 240 min after each food intake, without acarbose. Subsequently, three doses of 50 mg acarbose were given orally and the same procedure was repeated the following day. There were significantly lower mean increments in plasma glucose levels after compared to before acarbose treatment 30, 45 and 60 min for food A and at 30, 45, 60, 120, 180 and 240 min for food C, but no significant difference was noted for food B. There was a significantly lower mean fasting glucose level after compared with before acarbose treatment following intake of food A and C but not food B. Short-term treatment with acarbose caused significant diminished and delayed PPH response with food A and C but not with food B. Acarbose was more effective in reducing PPH response in polysaccharide foods with a higher and earlier postprandial glucose peak than in those with a lower and lagged peak. There were no significant differences in the mean fasting or postprandial triglyceride levels before and after acarbose treatment, following intake of all three foods for up to 4 hours. Depending on the food absorption pattern, overnight low dose treatment with acarbose leads to diminished fasting and peak plasma glucose levels, and delayed PPH but insignificant reduction in postprandial lipaemia in poorly controlled type 2 diabetics following intake of racially different Malaysian

  18. Development of TEC fluctuations in northern and southern hemispheres on the base of GPS observations

    NASA Astrophysics Data System (ADS)

    Shagimuratov, Irk; Krankowski, Andrzej; Sieradzki, Rafal; Ephishov, I. I.

    GPS technique is widely used to study the global structure and dynamics of the ionosphere. In this paper GPS observations carried out at Arctic and Antarctic stations belonging to the IGS network were used to study TEC fluctuations in the high-latitude ionosphere during the ionospheric storms. Dual-frequency GPS phase measurements along individual satellite passes served as raw data. It was shown that ionospheric irregularities of a different scale were devel-oped in the auroral and polar ionosphere. It is a common phenomenon caused phase fluctuations of GPS signals. In November 2009, West Department of IZMIRAN in Kaliningrad (Russia) and University of Warmia and Mazury in Olsztyn (Poland) established computer server for automatic monitoring of these irregularities. The rate of TEC index (ROTI) expressed in TECU/min was used as a measure of TEC fluctuations. During its operation TEC variations related to ionospheric structures of a spatial scale more than 200-300 km were detected. Large-scale ionospheric structures cause an increase in horizontal gradients and difficulties with the carrier phase ambiguity resolution in GPS positioning. In turn, the phase fluctuations can cause cycle-slip effects. At the polar stations, ionospheric structures with TEC enhanced by a factor of 3-5 relative to the background were detected, whereas TEC increased to 5-8 TECU in about 10-15 min. These structures were observed during a storm, as well as during a moderate geomagnetic activity. It can be probably attributed to the polar cap patches. In this study are presented the extended and more detailed analyses of TEC fluctuations in both the northern and southern hemispheres and compare the winter and summer events (November and July 2004 storms). A special attention is given to the features related to TEC fluctuations occur-rence in both hemispheres for conjugated GPS stations. The temporal development of both storms was rather similar. During storms the intensity of irregularities

  19. Breastfeeding practices and health-seeking behavior for neonatal sickness in a rural community.

    PubMed

    Kaushal, Monika; Aggarwal, Rajiv; Singal, Ashwani; Shukla, Hemant; Kapoor, Suresh K; Paul, Vinod K

    2005-12-01

    The aim of the study was to evaluate the knowledge of mothers and grandmothers regarding breastfeeding and health-seeking behavior for neonatal sickness in a rural community. A cross-sectional survey, using a triangulation of qualitative (focus group discussion) and quantitative (structured questionnaire) methods was carried out. Although most of the grandmothers and mothers believed in early feeding within 2 h of delivery, they often administered prelacteal feeds such as ghutti and honey. Colostrum was considered beneficial. Most respondents believed that ghutti, water, or both should be given along with breastmilk. Diluted buffalo milk was the preferred choice if supplementation was required. It was thought that weaning should be introduced after 6 months of life. Mothers preferred to give dalia and khichri as the initial weaning food compared to roti and dal water by grandmothers. Both grandmothers and mothers felt that a baby who was playful and not crying excessively was usually healthy. Most of the respondents described the normal pattern of breathing, feeding, urination, and defecation adequately. Most of the grandmothers and mother's felt that by touching forehead and limbs of baby could reliably assess temperature. Refusal to feed was considered as a marker of a sickness by most grandmothers and mothers. However, they also believed that health-seeking for poor feeding could be delayed for 1 day. Respiratory distress was described by the presence of fast respiration, chest retractions, or noisy breathing. Most respondents did not know how to assess cyanosis or seizures. Jaundice was descried as yellowish discoloration of skin, eyes, and urine. Failure to pass urine for 4-6 h bothered most of the respondents. The first response to illness was home remedies. The choice of healthcare was unqualified village practitioners followed by government hospital. Knowledge regarding desirable breastfeeding practices was inadequate and quite a few inappropriate beliefs

  20. Regional Surface Electromyography of the Vastus Lateralis During Strength and Power Exercises.

    PubMed

    Earp, Jacob E; Stucchi, Diana T; DeMartini, Julie K; Roti, Melissa W

    2016-06-01

    Earp, JE, Stucchi, DT, DeMartini, JK, and Roti, MW. Regional surface electromyography of the vastus lateralis during strength and power exercises. J Strength Cond Res 30(6): 1585-1591, 2016-Neuromuscular activation during and chronic adaptation from exercise are innately linked and both can vary along a muscle's length. During high-force and high-speed exercise, intramuscular hypertrophy follows set patterns that provide the greatest biomechanical advantages. However, it is unknown if muscle activity as recorded by surface electromyography (sEMG) will follow these patterns. The purpose of the present study was to compare vastus lateralis intramuscular sEMG during the heavy squat (HS) and unloaded jump squat (JS) exercises. Ten subjects performed HS with 80% of maximum load and unloaded JS to parallel-depth, while intramuscular peak sEMG and mean sEMG were measured at 33% (proximal), 50% (middle), and 67% (distal) thigh length. Muscle activity was compared between regions and exercises using a 3 × 2 repeated measures ANOVA with Bonferoni post hoc corrections. Peak sEMG was greater proximally in JS than HS (p = 0.033), but similar in the middle and distal regions (p = 0.521, 0.594, respectively), whereas mean sEMG was similar between all regions (p = 0.150-0.979). In addition, a main effect was found in which peak and mean sEMG were greater proximally than the middle and distal regions (p = 0.001, 0.006). Muscle activity measured using sEMG displayed dissimilar patterns to previously observed regional hypertrophy. Specifically, although previous research found greater proximal hypertrophy in JS than HS, in the present study peak sEMG was greater in HS than JS. Furthermore, distally where HS elicited greater hypertrophy than JS, no differences in sEMG were present. Thus, regional sEMG appears not to be a viable tool for predicting differences in regional hypertrophy, most likely due to technological constraints and intramuscular differences in muscle structure. PMID

  1. The multi-instrumental radio diagnostics of the ionosphere for Space Weather Program

    NASA Astrophysics Data System (ADS)

    Krankowski, Andrzej; Rothkaehl, Hanna; Pulinets, Sergey; Cherniak, Iurii; Zakharenkova, Irina

    2015-04-01

    To give a more detailed and complete understanding of physical plasma processes that govern the solar-terrestrial space, and to develop qualitative and quantitative models of the magnetosphere-ionosphere-thermosphere coupling, it is necessary to design and build the next generation of instruments for space diagnostics and monitoring. Novel ground- based wide-area sensor networks, such as the LOFAR (Low Frequency Array) radar facility, comprising wide band, and vector-sensing radio receivers and multi-spacecraft plasma diagnostics should help to solve outstanding problems of space physics and describe long-term environmental changes. The LOw Frequency ARray - LOFAR - is a new fully digital radio telescope designed for frequencies between 30 MHz and 240 MHz located in Europe. The three new LOFAR stations will be installed until summer 2015 in Poland. The LOFAR facilities in Poland will be distributed among three sites: Lazy (East of Krakow), Borowiec near Poznan and Baldy near Olsztyn. Each site will host one LOFAR station (96 high-band+96 low-band antennas). The new digital radio frequency analyzer (RFA) on board the low-orbiting RELEC satellite was designed to monitor and investigate the ionospheric plasma properties. In addition to the in-situ space plasma measurements the topside sounders will be installed onboard the "Ionosphere" spacecrafts to retrieve the vertical distribution of electron concentration in the topside ionosphere. The first two satellites are scheduled for launch at the first half of 2016. These two-point ground-based and topside ionosphere-located space plasma diagnostic can be a useful new tool for monitoring and diagnosing turbulent plasma properties. In order to improve and validate the large scale and small scale ionospheric structures we will also use the GPS observations collected at IGS/EPN: global and regional TEC maps created with high special and temporal resolution, ROTI maps over the Northern Hemisphere and the data retrieved from

  2. Summer time scintillations near the transition zone of the Indian longitude sector

    NASA Astrophysics Data System (ADS)

    Chatterjee, S.; Chakraborty, S. K.; Majumdar, S.

    2013-04-01

    Multisatellite summer solstice (May-July, 2011) daytime as well as nighttime scintillations are recorded simultaneously from two locations (i) Raja Peary Mohan College (RPMC) (geographic: 22.66°N, 88.39°E; dip 33°5/N), (ii) Krishnath College (KNC) (geographic: 24.1°N, 88.32°E; dip 35°54/N). The stations are situated more or less along the same meridian around the northern crest of the equatorial ionization anomaly (EIA) as well as near the equator to mid latitude transition zone. Due to the peculiar location of the observing stations both the equatorial and mid latitude type irregularity phenomena are investigated for a comparative study of their spatial and temporal evolution features. Remarkable differences are reflected in initiation time, strength, duration as well as spectral characteristics of scintillation at two locations at the respective time periods. Daytime scintillations are observed not only at VHF (250 MHz) but also at L1 frequencies of satellite constellation in GPS, GLONASS, and SBAS, though occurrence probability is remarkably low. These are mostly related to mid latitude sporadic E type irregularity with earlier initiation at KNC followed by equatorward drift/expansion. A clear temporal evolution pattern reveals that irregularities either of the equatorial F layer or mid latitude sporadic E type are responsible for nighttime scintillation at the transition zone. A few cases of longer duration (>4 h.) moderate (S4≈0.3-0.4) to intense (S4≈0.6-1.1) scintillation are recorded with distinct Fresnel's oscillation signifying Bottom Side Sinusoidal (BSS) type irregularity which is sometimes associated with weak bubble. Scintillations at L1 frequencies are mostly associated with fluctuations in dTEC and increase in ROTI. Latitudinal gradient as well as location of northern EIA peak, as revealed through TEC distribution, seem to play dominant role in destabilizing the ionosphere to exhibit scintillation effects. The results are discussed in terms

  3. A Mathematical Model of Human Papillomavirus (HPV) in the United States and its Impact on Cervical Cancer

    PubMed Central

    Lee, Shernita L.; Tameru, Ana M.

    2012-01-01

    susceptible population, however, if mitigation is to be implemented effectively it should focus on the HPV untreated population as ROTis greater than 0.5. Conclusion: Mathematical models, from individual and population perspectives, will help decision makers to evaluate different prevention and mitigation measures of HPV and deploy synergistically to improve cancer outcomes. Integrating the best-available epidemiologic data, computer-based mathematical models used in a decision-analytic framework can identify those factors most likely to influence outcomes and can help in formulating decisions that need to be made amidst considerable lack of data and uncertainty. Specifically, the model provides a tool that can accommodate new information, and can be modified as needed, to iteratively assess the expected benefits, costs, and cost-effectiveness of different policies in the United States. This model can help show the direct relationship between HPV and cervical cancer. If any of the rates change it will greatly impact the graphs. These graphs can be used to discover new methods of treatment that will decrease the rate of infectivity of HPV and Cervical cancer with time. PMID:22773930

  4. Developed Design for Humeral Head Replacement Using 3D Surface Mapping

    NASA Astrophysics Data System (ADS)

    Salah, H. R.

    2014-12-01

    Works. Biomehaniskajam PKGN dizainam tika atlasīti piemēroti materiāli. Apspriesta dažādu biomateriālu ar metālisko pamatu reakcija uz mainīgām slodzēm. Tiek piedāvāta pleca kaula galviņas - kā anatomiskas, tā mākslīgas - trīs dimensijas mērīšanas metodoloģijas. Dota datortomogrāfisko precīzo mērījumu rezultātu detalizēta interpretācija.

  5. Digital Base Band Converter As Radar Vlbi Backend / Dbbc Kā Ciparošanas Sistēma Radara Vlbi Novērojumiem

    NASA Astrophysics Data System (ADS)

    Tuccari, G.; Bezrukovs, Vl.; Nechaeva, M.

    2012-12-01

    can then allow exploring easily the desired range of search for unknown or not fully determined orbit objects. These features make Radar VLBI personality most useful in the space debris measurements. DBBC sistēma izstrādāta Noto Radioastronomijas institūtā. Sistēmas galvenaisuzdevums - palielināt visa Eiropas VLBI tīkla jutību - realizēts, palielinotvisas novērojamās joslas platumu un pielietojot ciparu signālu apstrādes metodes.Izejas datu plūsma palielināta no 1 līdz 4 Gbps katram radioteleskopam un visasoperācijas, kas saistītas ar signālu apstrādi (frekvences pārveidošana, pastiprinājums,iekšējie ģeneratori, utt.), realizētas digitālā formā, kas ļauj iegūt nozīmīgusuzlabojumus atkārtojamībā, precizitātē, vienkāršībā, nemaz neminot vispārzināmāspriekšrocības, ko nodrošina digitālo tehnoloģiju izmantošana. Maksimālā ieejassignāla frekvenču josla ir 3.5 GHz, un momentānais joslas platums ir līdz 1 GHz uzkatru no astoņiem iespējamajiem RF/IF kanāliem. Šī datu reģistrācijas sistēma irļoti veiktspējīga platforma ne tikai EVN, bet arī citiem radioastronomijas pielietojumiem,un papildus tiek izstrādāta vesela virkne programmatūras pakotņu, kasvēl vairāk paplašina sistēmas funkcionalitāti. Tas ietver PFB (Polifāzes FiltruBanka) uztvērējus "Spectra”, kas piemēroti augstas izšķirtspējas spektroskopijasvajadzībām. Papildus realizēts jaunas programmatūras risinājums, ar mērķiizmantot DBBC sistēmu kā daudzfunkcionālu datu ciparošanas iekārtu, kasizmantojama bistatiskiem radara novērojumiem, tai skaitā arī radara VLBInovērojumiem. Šāda veida novērojumos tiek pētīta kosmisko atlūzu populācija,nodrošinot iespēju detektēt pat centimetra