scholarly journals Global lightning distribution and whistlers observed at Dunedin, New Zealand

2010 ◽  
Vol 28 (2) ◽  
pp. 499-513 ◽  
Author(s):  
A. B. Collier ◽  
S. Bremner ◽  
J. Lichtenberger ◽  
J. R. Downs ◽  
C. J. Rodger ◽  
...  
Keyword(s):  
Magnetic Field ◽  
New Zealand ◽  
Field Line ◽  
Central America ◽  
Classical Model ◽  
Conjugate Point ◽  
The Other ◽  
Electromagnetic Signal ◽  
The West ◽  
Lightning Stroke

Abstract. Whistlers observed at Dunedin, New Zealand, are an enigma since they do not conform to the classical model of whistler production developed by Storey (1953). It is generally accepted that the causative lightning stroke for a whistler observed on the ground at a particular location was located in the neighbourhood of the conjugate point, and generated an electromagnetic signal which propagated in a plasmaspheric duct stretched along a magnetic field line linking the two hemispheres. The causative stroke is thought to have occurred within reasonable proximity of one footpoint of this field line, while the observer was located in the vicinity of the other footpoint. Support for this model has come from a number of previous studies of whistler-lightning observations and whistler-induced particle precipitation. However, as demonstrated here, this model does not always apply. Whistlers detected at Dunedin are nearly as common as those at Tihany, Hungary, despite there being at least 3 orders of magnitude more lightning in Tihany's conjugate region compared to that of Dunedin. Furthermore, whereas Tihany whistlers are generally observed at night, consistent with historical observations, Dunedin whistlers occur predominantly during the day. This paper aims to resolve two paradoxes regarding whistler occurrence at Dunedin: (i) an observation rate which is at variance with conjugate lightning activity, and (ii) a diurnal occurrence peak during daylight. The technique developed by Collier et al. (2009) is used to diagnose the location of the source lightning for Dunedin whistlers. It is found that the majority of the causative strokes occur within a region extending down the west coast of Central America.

B-fields and gas motion in the L1689 region: an interpretation of Planck polarization data

2018 ◽  
Vol 14 (A30) ◽  
pp. 107-107
Author(s):  
Masafumi Matsumura ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Position Angle ◽  
The Other ◽  
Spatial Gradient ◽  
East Side ◽  
Polarization Data ◽  
The West ◽  
Complete Survey ◽  
The Magnetic Field

AbstractWith using the Planck polarization data (PR2, 2016A A…596A.109P), we investigate the magnetic fields in L1689 and associated clouds, and compare them with centroid velocities VLSR of 12CO and 13CO from the COMPLETE survey (2006AJ….131.2921R). We observe two components in this elongated region: in one component, the position angle of the magnetic field varies from –10 to 110 degrees in the galactic coordinate, while VLSR is rather constant (=4 ± 0.5 km/s). In the other component with the position angle being constant (=110 ± 15 degrees), the velocity VLSR shows a spatial gradient from 3 to 5 km/s, as one goes from west to east along the direction of elongation. If the east side of the component is more distant from us than the west, this gradient suggests that this component is stretching. This work is supported by JSPS KAKENHI Grant Number JP18H03720 (PI: Koji S. Kawabata).

The Simuliidae (Diptera) of British Honduras

1960 ◽  
Vol 50 (4) ◽  
pp. 703-710 ◽  
Author(s):  
D. J. Lewis ◽  
P. C. C. Garnham
Keyword(s):  
Central America ◽  
The Other ◽  
Detailed Knowledge ◽  
Risk Of Infection ◽  
The West ◽  
Secondary Importance ◽  
Pine Ridge ◽  
Mountain Pine ◽  
British Honduras ◽  
Made In

Several collections of pupae and adults of Simuliid Diptera were made in British Honduras between 9th January and 18th February 1958. Samples were collected in the Mountain Pine Ridge and El Cayo areas in the west, and along the highway traversing the eastern part of the country between Caves Branch and Stann Creek.Thirteen species of Simulium were found, nine of which are named, including S. quadrivittatum Lw. and S. metallicum Bellardi which are very annoying biters. A, few observations on distribution and habits are recorded.Of the two anthropophilic species of Simulium found, one is known to be a vector of onchocerciasis, if only of secondary importance, and the capability of the other to transmit the disease is unknown. The disease has apparently never been established in British Honduras and is present in Guatemala. The risk of infection to settlers moving into territory near Guatemala cannot be assessed without detailed knowledge of the epidemiology of the disease in Central America.

scholarly journals Huirangi

Te Kaharoa ◽  
2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Henare King
Keyword(s):  
New Zealand ◽  
Indigenous Knowledge ◽  
The Other ◽  
The West ◽  
Far North ◽  
Aotearoa New Zealand

The book “The Tail of the Fish” was publised in 1968 and written by a Te Aupouri kuia, Matire Kereama (nee: Hoeft) of the far north of Aotearoa, New Zealand. I grew up with this book as my grandmother would read the stories to me at bedtime. Although my comprehension of each story was very vague and unrelatable to my life at that time, today, I find myself totally absorbed by the historical content and knowledge encapsulated in each chapter. I completed a Masters of Applied Indigenous Knowledge at Te Wananga o Aotearoa in 2017, entitled; Tales of the singing fish: He tangi wairua. I compsed twelve waiata (Maori songs) of which ten of the waiata was information extracted from ten chapters of the book. The other two waiata were composed specifically for my people of the Te Rarawa tribe, namely, Ahipara. This waiata is a dedication to Huirangi Tahana of the Ngāti Māhanga people of Waingaro Marae located 36 kilometers to the west of Ngaruawahia in the Waikato district.

Quasi Periodic Oscillations in the Pre Phases of Recurrent Jets Highlighting Plasmoids in Current Sheet

2020 ◽  
Author(s):  
Reetika Joshi ◽  
Ramesh Chandra ◽  
Brigitte Schmieder ◽  
Guillaume Aulanier ◽  
Pooja Devi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
The Other ◽  
Active Region Noaa ◽  
The West ◽  
Periodic Oscillations ◽  
West Limb ◽  
Field Lines ◽  
Open Magnetic Field ◽  
Double Chamber

<p><strong>Solar jets observed at the limb are important to determine the location of reconnection sites in the corona. In this study, we investigate six recurrent hot and cool jets occurring in the active region NOAA 12644 as it is crossing the west limb on April 04, 2017. These jets are observed in all the UV/EUV filters of SDO/AIA and in cooler temperature formation lines in IRIS slit jaw images. The jets are initiated at the top of a double chamber vault with cool loops on one side and hot loops on the other side. The existence of such double chamber vaults suggests the presence of emerging flux with cool loops, the hot loops being the reconnected loops similarly as in the models of Moreno-</strong><strong>Insertis</strong><strong>et al. 2008, 2013 and Nóbrega-Siverio et al. 2016. In the preliminary phase of the main jets, </strong><strong>quasi periodic</strong><strong> intensity oscillations accompanied by smaller jets are detected in the bright current sheet between the vault and the preexisting magnetic field. Individual kernels and plasmoids are ejected in open field lines </strong><strong>along</strong><strong> the jets. Plasmoids may launch torsional Alfven waves and the kernels would be the result of the </strong><strong>untwist</strong><strong> of the plasmoids in open magnetic field as proposed in the model of Wyper et al. 2016.</strong></p>

scholarly journals Conjugate Conductivity Asymmetry and the Precipitation of Magnetospheric Electrons

1971 ◽  
Vol 24 (4) ◽  
pp. 881
Author(s):  
JR Catchpoole
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Magnetic Field Line ◽  
Conjugate Point ◽  
Potential Difference ◽  
Simplified Model ◽  
Trapped Electrons ◽  
Set Up ◽  
The Magnetic Field

Using a simplified model of the atmosphere, a calculation is made of the windinduced vertical redistribution of ions derived from the 100 km level. Assuming the effect to be dissimilar in magnitude at the conjugate point, a potential difference will be set up in this way between the ends of the magnetic field line. For various values of the parameters involved, an estimate is made of the consequent precipitation to ionospheric heights of previously trapped electrons of the magnetosphere.

scholarly journals Allosidastrum, un nuevo género de Malvaceae de los neotrópicos

2017 ◽  
pp. 23
Author(s):  
Antonio Krapovickas ◽  
Paul A. Fryxell ◽  
David M. Bates
Keyword(s):  
Central America ◽  
West Indies ◽  
The Other ◽  
The West ◽  
Widespread Species ◽  
Distinct Genus

Four species that have been variously included by previous authors in the genera Sida or Pseudabutilon are segregated as the distinct genus, Allosidastrum (Hochr.) stat. nov. A .,dolichophyllum from Venezuela is described as new. The most widespread species is A . pyramidatum (Cav.) comb. nov., which occurs over most of the range of the genus from Mexico and the West Indies to parts of Brazil and Bolivia. The other two species, A. hilarianum (Presl) comb. nov. and A. interruptum (DC.) comb. nov., are found in Mexico, Central America, and Colombia.

The Muhammad cartoon controversy in New Zealand newspapers

2021 ◽  
Vol 14 (1) ◽  
pp. 143-156
Author(s):  
Shah Nister Kabir
Keyword(s):  
New Zealand ◽  
Freedom Of Expression ◽  
Minority Group ◽  
The Other ◽  
Political Agenda ◽  
The West ◽  
Visual Texts ◽  
News Frame ◽  
Clash Of Cultures

This study examines the construction of the controversy surrounding the cartoons of the Prophet Muhammad, as it appeared in three New Zealand newspapers and discursively identifies how three New Zealand newspapers framed Islam and Muslims from an Orientalist perception. This study argues that these newspapers framed the issue of Muhammad cartoon controversial image in a way that reinforces the notion of a clash of culture between Islam and ‘the West’ and identified that Islam is a threat to the civilization. The metaphors employed, the visual texts incorporated, the terminologies they imposed appear to dehumanize Islam and Muslims, which also violates the philosophical stand of the freedom of expression. The news frame that these newspapers adopted in covering the controversial cartoon issue also supports an elite political agenda without respecting the religious norms of a minority group. However, the dehumanization of Islam and Orientalist perception of clash of cultures were mostly absent in their editorials. Therefore, the news frame conflicts with editorials’ construction of the issue in most cases. Furthermore, while one newspaper’s editorials dehumanized Islam and Muslims by espousing Orientalist perception of clash of cultures, the other two played a constructive role towards Islam and Muslims.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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