An Analysis of the Oxford Bilingual School Dictionary: Northern Sotho and English (De Schryver 2007)

The Oxford Bilingual School Dictionary: Northern Sotho and English (De Schryver 2007) is a welcome addition to dictionaries that have been compiled for school use in particular. Its novelty and appeal lie in the fact that the lemmas and Northern Sotho mini-grammar are based on a corpus of general language usage and school textbooks. It reflects current language usage and concerns in the modern world that learners can easily relate to, making it a popular alternative to the more traditional dictionaries. This bidirectional, bilingual dictionary is equally useful to native speakers of Northern Sotho learning English and to English-speakers acquiring Northern Sotho. Though the number of lemmas is restricted to 5 000 in the lemma lists for Northern Sotho and English respectively, the compilers nevertheless succeeded in meeting the basic lexicographic and grammatical needs of the learner. This review article aims to take a critical look at various features of the dictionary.Keywords: sesotho sa leboa, corpus, school dictionary, dictionary culture, lemmatisation, access alphabet, cross-references, lemma, minigrammar, modernit

Challenges of Predictability and Consistency in the First Comprehensive Sotho Dictionary

Predictability and consistency are requirements that should run like a golden thread through the macro-, medio- as well as the microstructure of dictionary articles. Adherence to these requirements is one of the marks of a user-friendly reference work that will allow for easy access and trouble-free retrieval of required information. This article aims to investigate some features of Endemann's (1911) Wörterbuch der Sotho-Sprache (Dictionary of the Sotho language) with the focus on challenges of predictability and consistency in the lemmatization approach, the access alphabet, cross references and article treatments. The dictionary has hitherto remained at the outskirts of scholarly investigation, one of the reasons being the fact that the target language is German and that, as such, it is not readily accessible to every scholar of the Bantu languages. A further reason is that it is aimed at subject specialists rather than the general public and places a high demand on the lexicographic skill of the user. Some interesting insights can be gained from this example of an early attempt at dictionary compilation and its shortcomings can serve as a springboard for continual improvement of access routes and user-friendliness of dictionaries in the Sotho languages. Keywords: Predictability, Consistency, Comprehensive Dictionary, Sotho Languages, Dictionary User, Lemmatization Strategy, Cross References, Alphabetization, Word Lemmatization, Stem Lemmatization, Data Categorie

Mesoscale observations of Joule heating near an auroral arc and ion-neutral collision frequency in the polar cap E region

We report on the first mesoscale combined ionospheric and thermospheric observations, partly in the vicinity of an auroral arc, from Svalbard in the polar cap on 2 February 2010. The EISCAT Svalbard radar employed a novel scanning mode in order to obtain F and E region ion flows over an annular region centered on the radar. Simultaneously, a colocated Scanning Doppler Imager observed the E region neutral winds and temperatures around 110 km altitude using the 557.7 nm auroral optical emission. Combining the ion and neutral data permits the E region Joule heating to be estimated with an azimuthal spatial resolution of ∼64 km at a radius of ∼163 km from the radar. The spatial distribution of Joule heating shows significant mesoscale variation. The ion-neutral collision frequency is measured in the E region by combining all the data over the entire field of view with only weak aurora present. The estimated ion-neutral collision frequency at ∼113 km altitude is in good agreement with the MSIS atmospheric model

High-latitude artificial aurora using the EISCAT high-gain HF facility

The EISCAT high-frequency (HF) transmitter facility at Ramfjord, Norway, has been used to accelerate F-region electrons sufficiently to excite the oxygen atoms and nitrogen molecules, resulting in optical emissions at 630, 557.7 and 427.8 nm. During O-mode transmissions at 5.423 MHz, using 630 MW effective radiated power, in the hours after sunset on 12 November 2001 several new observations were made, including: (1) The first high-latitude observation of an HF induced optical emission at 427.8 nm and (2) Optical rings being formed at HF on followed by their collapse into a central blob. Both discoveries remain unexplained with current theories

Dynamics of Alfvén waves in the night-side ionospheric Alfvén resonator at mid-latitudes

International audienceA numerical solution of the problem on dynamics of shear-mode Alfvén waves in the ionospheric Alfvén resonator (IAR) region at middle latitudes at nighttime is presented for a case when a source emits a single pulse of duration ? into the resonator region. It is obtained that a part of the pulse energy is trapped by the IAR. As a result, there occur Alfvén waves trapped by the resonator which are being damped. It is established that the amplitude of the trapped waves depends essentially on the emitted pulse duration ? and it is maximum at ?=(3/4)T, where T is the IAR fundamental period. The maximum amplitude of these waves does not exceed 30% of the initial pulse even under optimum conditions. Relatively low efficiency of trapping the shear-mode Alfvén waves is caused by a difference between the optimum duration of the pulse and the fundamental period of the resonator. The period of oscillations of the trapped waves is approximately equal to T, irrespective of the pulse duration ?. The characteristic time of damping of the trapped waves ?dec is proportional to T, therefore the resonator Q-factor for such waves is independent of T. For a periodic source the amplitude-frequency characteristic of the IAR has a local minimum at the frequency ?/?=(3/4)T, and the waves of such frequency do not accumulate energy in the resonator region. At the fundamental frequency ?=2?/T the amplitude of the waves coming from the periodic source can be amplified in the resonator region by more than 50%. This alone is a basic difference between efficiencies of pulse and periodic sources of Alfvén waves. Explicit dependences of the IAR characteristics (T, ?dec, Q-factor and eigenfrequencies) on the altitudinal distribution of Alfvén velocity are presented which are analytical approximations of numerical results

Global diagnostics of ionospheric absorption during X-ray solar flares based on 8-20MHz noise measured by over-the-horizon radars

An analysis of noise attenuation during eighty solar flares between 2013 and 2017 was carried out at frequencies 8-20 MHz using thirty-four SuperDARN radars and the EKB ISTP SB RAS radar. The attenuation was determined on the basis of noise measurements performed by the radars during the intervals between transmitting periods. The location of the primary contributing ground sources of noise was found by consideration of the propagation paths of radar backscatter from the ground. The elevation angle for the ground echoes was determined through a new empirical model. It was used to determine the paths of the noise and the location of its source. The method was particularly well suited for daytime situations which had to be limited for the most part to only two crossings through the D region. Knowing the radio path was used to determine an equivalent vertical propagation attenuation factor. The change in the noise during solar flares was correlated with solar radiation lines measured by GOES/XRS, GOES/EUVS, SDO/AIA, SDO/EVE, SOHO/SEM and PROBA2/LYRA instruments. Radiation in the 1 to 8$\mathring{A}$ and and near 100$\mathring{A}$ are shown to be primarily responsible for the increase in the radionoise absorption, and by inference, for an increase in the D and E region density. The data are also shown to be consistent with a radar frequency dependence having a power law with an exponent of -1.6. This study shows that a new dataset can be made available to study D and E region.Comment: 30 pages, 5 figures, 2 tables. Submitted to Space Weathe

OI 630.0-nm and N2 1PG Emissions in Pulsating Aurora Events Observed by an Optical Spectrograph at Tromsø, Norway

We performed observations of pulsating aurora (PsA) with an optical spectrograph at Tromsø, Norway, during wintertime in 2016–2017. The data analysis of multiple PsA events revealed the PsA spectra for the first time. As the results, the OI 630.0-nm emissions and the N2 1PG emissions were found in the both spectra during brighter (ON) and darker (OFF) phases in the PsA events. The spectra of pulsations were derived as difference spectra between the ON and OFF spectra. From the obtained spectra of pulsations, it is found that dominant pulsations at 630.0 nm were coming from the N2 1PG (10,7) band, and there were less or minor contributions of the OI 630.0 nm to pulsations at 630.0 nm

Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity

Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease