scholarly journals Mean Zonal Drift Velocities of Plasma Bubbles Estimated from Keograms of Nightglow All-Sky Images from the Brazilian Sector

2019 ◽  
Author(s):  
Fabio Vargas ◽  
Christiano Brum ◽  
Pedrina Terra ◽  
Delano Gobbi
Keyword(s):  
Standard Deviation ◽  
Drift Velocity ◽  
Velocity Estimation ◽  
Plasma Bubble ◽  
The West ◽  
Equatorial Station ◽  
Plasma Bubbles ◽  
Latitude Station ◽  
The Mean

We present in this work a method for estimation of plasma bubble mean zonal drift velocities using keograms generated from images of the OI 6300.0 nm nightglow emission collected from an equatorial station -- Cariri (7.4$^\circ$S, 36.5$^\circ$W), and a mid-latitude station -- Cachoeira Paulista (22.7$^\circ$S, 45$^\circ$W), both in the Brazilian sector. The mean zonal drift velocities were estimated for 239 events recorded from 2000 to 2003 in Cariri, and for 56 events recorded over Cachoeira Paulista from 1998 to 2000. It was found that plasma bubble zonal drift velocities are smaller ($\sim$60 ms$^{-1}$) for events occurring later in the night compared to those occurring earlier ($\sim$150 ms$^{-1}$). The decreasing rate of the zonal drift velocity is of $\sim$10 ms$^{-1}$/h. We have also found that, in general, bubble events appearing first in the west-most region of the keogram are faster than those appearing first in the east-most region of the keograms. Larger zonal drift velocities occur from 19 LT to 23 LT in a longitude range from 37$^\circ$ to 33$^\circ$. The method of velocity estimation using keograms compares favorably against the mosaic method developed by \cite{Arruda:2005}, but the standard deviation of the residuals for the zonal drift velocities from the two methods is $\sim$15 ms$^{-1}$

scholarly journals Mean Zonal Drift Velocities of Plasma Bubbles Estimated from Keograms of Nightglow All-Sky Images from the Brazilian Sector

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 69
Author(s):  
Fabio Vargas ◽  
Christiano Brum ◽  
Pedrina Terra ◽  
Delano Gobbi
Keyword(s):  
Standard Deviation ◽  
Drift Velocity ◽  
Zonal Wind ◽  
Velocity Estimation ◽  
Plasma Bubble ◽  
The West ◽  
Equatorial Station ◽  
Plasma Bubbles ◽  
The Mean ◽  
Vertical Gradients

We present in this work a method for estimation of equatorial plasma bubble (EPB) mean zonal drift velocities using keograms generated from images of the OI 6300.0 nm nightglow emission collected from an equatorial station–Cariri (7.4° S, 36.5° W), and a mid-latitude station–Cachoeira Paulista (22.7° S, 45° W), both in the Brazilian sector. The mean zonal drift velocities were estimated for 239 events recorded from 2000 to 2003 in Cariri, and for 56 events recorded over Cachoeira Paulista from 1998 to 2000. It was found that EPB zonal drift velocities are smaller (≈60 ms−1) for events occurring later in the night compared to those occurring earlier (≈150 ms−1). The decreasing rate of the zonal drift velocity is ≈10 ms−1/h. We have also found that, in general, bubble events appearing first in the west-most region of the keograms are faster than those appearing first in the east-most region. Larger zonal drift velocities occur from 19 to 23 LT in a longitude range from −37° to −33°, which shows that the keogram method can be used to describe vertical gradients in the thermospheric wind, assuming that the EPBs drift eastward with the zonal wind. The method of velocity estimation using keograms compares favorably against the mosaic method developed by Arruda, D.C.S, 2005, but the standard deviation of the residuals for the zonal drift velocities from the two methods is not small (≈15 ms−1).

scholarly journals The study of equatorial plasma bubble during January to April 2012 over Kolhapur (India)

2016 ◽  
Vol 59 (2) ◽  
Author(s):  
Parashram T. Patil ◽  
Rupesh N. Ghodpage ◽  
Alok K. Taori ◽  
Rohit P. Patil ◽  
Subramanian Gurubaran ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Emission Line ◽  
Drift Velocity ◽  
Velocity Variation ◽  
Plasma Bubble ◽  
Low Latitude ◽  
Plasma Bubbles ◽  
F Region ◽  
Equatorial Plasma Bubbles ◽  
Observation Period

<p>Over 53 nights of all sky airglow imager data collected during January-April 2012 from the low latitude station Kolhapur (16.68°N, 74.26°E; 10.6°N dip latitude) have been analyzed to study the F-region dynamics through the imaging of OI 630 nm emission line. The observed night airglow data were supported by the ionosonde measurements from Tirunelveli (8.7°N, 77.8°E; 0.51°N dip latitude). Well defined magnetic field aligned depletions were observed during the observation period. Out of 53 nights, 40 nights exhibited the occurrence of north-south aligned equatorial plasma bubbles. These plasma bubbles were found moving towards east with drift speed in range between 70 to 200 m s<span><sup>-1</sup></span>. We have analyzed the zonal drift velocity variation and relation of bubble occurrence with the base height of the ionosphere together with the effects of the geomagnetic Ap and solar flux F<span><sub>10.7</sub></span> cm index in its first appearance.</p>

scholarly journals Ionospheric height variations observed by ionosondes along magnetic meridian and plasma bubble onsets

2006 ◽  
Vol 24 (11) ◽  
pp. 2991-2996 ◽  
Author(s):  
S. Saito ◽  
T. Maruyama
Keyword(s):  
Continuous Wave ◽  
Plasma Bubble ◽  
Thermospheric Wind ◽  
Bubble Generation ◽  
Equatorial Station ◽  
Plasma Bubbles ◽  
F Region ◽  
Ionospheric Height ◽  
Magnetic Meridian ◽  
South Asymmetry

Abstract. Since October 2004, a Frequency Modulated–Continuous Wave (FM–CW) ionosonde chain along the magnetic meridian has been operating in Southeast Asia, in Kototabang (0.2° S, 100.3° E), Indonesia, Chumphon (10.7° N, 99.4° E), Thailand, and Chiang Mai (18.8° N, 98.9° E), Thailand. Variations in the virtual height of the bottomside of the F-region (h'F) at 2.5 MHz were analyzed, in order to study the day-to-day variability of plasma bubble occurrence for the periods of October 2004 and March–April 2005. When plasma bubbles were generated, h'F was enhanced at the three stations. However, even when h'F at the equatorial station, Chumphon, was largely enhanced, plasma bubbles were not generated when a noticeable north-south asymmetry of h'F existed. This asymmetry could be attributed to the transequatorial thermospheric wind. Our results show that the strong transequatorial thermospheric wind can suppress the plasma bubble generation and is one of the important factors which controls the day-to-day variability of plasma bubble occurrences.

scholarly journals Temperature and precipitation conditions in Argentina associated with strong westerly mid-latitute

2008 ◽  
Vol 23 (2) ◽  
pp. 126-142 ◽  
Author(s):  
Adelia Perla Alessandro
Keyword(s):  
Standard Deviation ◽  
The South ◽  
The West ◽  
Temperature Anomalies ◽  
Zonal Index ◽  
Temperature And Precipitation ◽  
Southern Patagonia ◽  
The Mean ◽  
The Difference

This paper analyzes the incidence on temperature and precipitation of strong circulation from the west in the neighborhood of 45ºS. Circulation is estimated by a zonal index applied at 100º, 70º and 40ºW at 500 hPa and the strong circulation days by those which indices are smaller than the difference between the mean and the standard deviation of the daily indices from 1989 to 1998. When strong circulation from the west is calculated at 100º W, temperature anomalies over the country are positive in general and higher than 1ºC in southern Patagonia. Precipitation frequencies are greater than normal in southern Patagonia and the WNW of the country, and smaller in the remaining areas. Temperature anomalies are positive in practically the whole of Argentina and precipitation values greater than normal are practically confined to the south of 42ºS when the circulation from the west is more intense at 70ºW. For the same wind conditions at 40ºW, temperature anomalies are negative in Patagonia and positive in the NE and center of the country, while the greatest precipitation frequencies are found in most of the country except the western provinces. Temperature and precipitation values obtained under the analyzed conditions can be forecast with more than 69% probability when the index on 1 or 2 previous days was negative.

At Least One Standard Deviation Above the Mean

1969 ◽  
Vol 14 (9) ◽  
pp. 470-471
Author(s):  
M. DAVID MERRILL
Keyword(s):  
Standard Deviation ◽  
The Mean

The Estimation of Blood Platelet Survival

1972 ◽  
Vol 28 (03) ◽  
pp. 447-456 ◽  
Author(s):  
E. A Murphy ◽  
M. E Francis ◽  
J. F Mustard
Keyword(s):  
Standard Deviation ◽  
Least Squares ◽  
Experimental Error ◽  
Blood Platelet ◽  
Least Squares Estimation ◽  
Systematic Relationship ◽  
Platelet Survival ◽  
The Mean ◽  
Normally Distributed

SummaryThe characteristics of experimental error in measurement of platelet radioactivity have been explored by blind replicate determinations on specimens taken on several days on each of three Walker hounds.Analysis suggests that it is not unreasonable to suppose that error for each sample is normally distributed ; and while there is evidence that the variance is heterogeneous, no systematic relationship has been discovered between the mean and the standard deviation of the determinations on individual samples. Thus, since it would be impracticable for investigators to do replicate determinations as a routine, no improvement over simple unweighted least squares estimation on untransformed data suggests itself.

PENGARUH PENDIDIKAN KESEHATAN REPRODUKSI PADA PEER GROUP (TEMAN SEBAYA) TERHADAP PENGETAHUAN DAN PERSEPSI REMAJA TENTANG PENDEWASAAN USIA PERKAWINAN DI SMA NEGERI 1 KECAMATAN NAMORAMBE KAB. DELI SERDANG 2018

2020 ◽  
Vol 1 (2) ◽  
pp. 56-66
Author(s):  
Irma Linda
Keyword(s):  
Standard Deviation ◽  
Health Education ◽  
Reproductive Health ◽  
Peer Group ◽  
Peer Groups ◽  
A Value ◽  
Significant Difference ◽  
Reproductive Health Education ◽  
The Mean ◽  
Adolescent Perceptions

Background: Early marriages are at high risk of marital failure, poor family quality, young pregnancies at risk of maternal death, and the risk of being mentally ill to foster marriage and be responsible parents. Objective: To determine the effect of reproductive health education on peer groups (peers) on the knowledge and perceptions of adolescents about marriage age maturity. Method: This research uses the Quasi experimental method with One group pre and post test design, conducted from May to September 2018. The statistical analysis used in this study is a paired T test with a confidence level of 95% (α = 0, 05). Results: There is an average difference in the mean value of adolescent knowledge between the first and second measurements is 0.50 with a standard deviation of 1.922. The mean difference in mean scores of adolescent perceptions between the first and second measurements was 4.42 with a standard deviation of 9.611. Conclusion: There is a significant difference between adolescent knowledge on the pretest and posttest measurements with a value of P = 0.002, and there is a significant difference between adolescent perceptions on the pretest and posttest measurements with a value of p = 0.001. Increasing the number of facilities and facilities related to reproductive health education by peer groups (peers) in adolescents is carried out on an ongoing basis at school, in collaboration with local health workers as prevention of risky pregnancy.

Regularity and latency of units in ventral cochlear nucleus: implications for unit classification and generation of response properties

1988 ◽  
Vol 60 (1) ◽  
pp. 1-29 ◽  
Author(s):  
E. D. Young ◽  
J. M. Robert ◽  
W. P. Shofner
Keyword(s):  
Standard Deviation ◽  
Cochlear Nucleus ◽  
Interspike Interval ◽  
Rate Adaptation ◽  
Stellate Cells ◽  
Instantaneous Rate ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cell ◽  
Low Pass ◽  
The Mean

1. The responses of neurons in the ventral cochlear nucleus (VCN) of decerebrate cats are described with regard to their regularity of discharge and latency. Regularity is measured by estimating the mean and standard deviation of interspike intervals as a function of time during responses to short tone bursts (25 ms). This method extends the usual interspike-interval analysis based on interval histograms by allowing the study of temporal changes in regularity during transient responses. The coefficient of variation (CV), equal to the ratio of standard deviation to mean interspike interval, is used as a measure of irregularity. Latency is measured as the mean and standard deviation of the latency of the first spike in response to short tone bursts, with 1.6-ms rise times. 2. The regularity and latency properties of the usual PST histogram response types are shown. Five major PST response type classes are used: chopper, primary-like, onset, onset-C, and unusual. The presence of a prepotential in a unit's action potentials is also noted; a prepotential implies that the unit is recorded from a bushy cell. 3. Units with chopper PST histograms give the most regular discharge. Three varieties of choppers are found. Chop-S units (regular choppers) have CVs less than 0.35 that are approximately constant during the response; chop-S units show no adaptation of instantaneous rate, as measured by the inverse of the mean interspike interval. Chop-T units have CVs greater than 0.35, show an increase in irregularity during the response and show substantial rate adaptation. Chop-U units have CVs greater than 0.35, show a decrease in irregularity during the response, and show a variety of rate adaptation behaviors, including negative adaptation (an increase in rate during a short-tone response). Irregular choppers (chop-T and chop-U units) rarely have CVs greater than 0.5. Choppers have the longest latencies of VCN units; all three groups have mean latencies at least 1 ms longer than the shortest auditory nerve (AN) fiber mean latencies. 4. Chopper units are recorded from stellate cells in VCN (35, 42). Our results for chopper units suggest a model for stellate cells in which a regularly firing action potential generator is driven by the summation of the AN inputs to the cell, where the summation is low-pass filtered by the membrane capacitance of the cell.(ABSTRACT TRUNCATED AT 400 WORDS)

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