title: Exploring the impact of rainfall intensity on the attenuation-rainfall relationship

authors: Nia, Saeid Esmaeil

abstract: The attenuation of electromagnetic waves due to rainfall is a critical factor in radar and telecommunication systems, particularly in frequency bands above 10 GHz, which is increasingly utilised for data transfer. This study addresses the gaps in understanding how these attenuation effects vary across different rainfall intensities and Drop Size Distributions (DSD). By analytically investigating the irregularities in the cross-sections of raindrops within the 1 to 30 GHz frequency range, the study mentions significant peaks in attenuation at frequencies below 10 GHz, which are more pronounced as DSD changes with rainfall intensity. Using the extinction and efficiency cross-sections of raindrops in 1–30 GHz microwave transmission, the coefficients of rainfall-attenuation correlation were derived for each sector of rainfall intensity of 1–300 mm/hr. Building on these findings, we propose an enhanced rainfall-attenuation relationship, incorporating dynamic coefficients, varying with both factors, DSD and rainfall intensity. Unlike previous models that only suggest calibration of the attenuation-rainfall relationship with DSD, our results indicate that the coefficients should also dynamically adjust based on rainfall intensity. We further demonstrate how these varying coefficients differ from the ITU's recommendations, providing detailed graphical comparisons. This advancement allows for more accurate calculations of rainfall intensity, improving the precision of telecommunication and radar systems in diverse weather conditions.

text: Exploring the impact of rainfall intensity on the attenuation-rainfall relationship The attenuation of electromagnetic waves due to rainfall is a critical factor in radar and telecommunication systems, particularly in frequency bands above 10 GHz, which is increasingly utilised for data transfer. This study addresses the gaps in understanding how these attenuation effects vary across different rainfall intensities and Drop Size Distributions (DSD). By analytically investigating the irregularities in the cross-sections of raindrops within the 1 to 30 GHz frequency range, the study mentions significant peaks in attenuation at frequencies below 10 GHz, which are more pronounced as DSD changes with rainfall intensity. Using the extinction and efficiency cross-sections of raindrops in 1–30 GHz microwave transmission, the coefficients of rainfall-attenuation correlation were derived for each sector of rainfall intensity of 1–300 mm/hr. Building on these findings, we propose an enhanced rainfall-attenuation relationship, incorporating dynamic coefficients, varying with both factors, DSD and rainfall intensity. Unlike previous models that only suggest calibration of the attenuation-rainfall relationship with DSD, our results indicate that the coefficients should also dynamically adjust based on rainfall intensity. We further demonstrate how these varying coefficients differ from the ITU's recommendations, providing detailed graphical comparisons. This advancement allows for more accurate calculations of rainfall intensity, improving the precision of telecommunication and radar systems in diverse weather conditions.

year: 2025

title: An ERP N400 study: Semantic processing across modalities in the human brain

authors: Perry, Sarah

subjects: ERP

abstract: Semantic processing in the brain of both language and action has been associated with the N400; an event-related potential (ERP) that is typically present when information has violated one’s semantic expectations. We know that the brain receives and processes information from multiple modalities which means that cross-modal semantic processing is more aligned with how semantic processing is likely to occur in comparison to unimodal semantic processing. The N400 is a consistent effect across cross-modal language-based studies. But we know that the topographical distribution of the N400 does vary between language-based and non-language-based paradigms. Therefore, to investigate cross-modal semantic processing within the action domain, we presented participants with photographs portraying the implementation of common actions. These sequences concluded with a sound that was either congruent or incongruent with the prior action photographs. In our ERP study of 25 participants, with a mean age of 23 years (SD = 10.78 years), we¹ found an N400 effect for incongruent information processing. In addition, our findings showed a delayed N400 effect and a reduced P200 amplitude for incongruent information. These results suggest that cross-modal semantic processing of action sequences requires an increased cognitive workload which is evidenced when semantic processing does not progress as expected. Considered as a whole, these results indicate that cross-modal semantic processing is similar to unimodal processing. Cross-modal information likely requires the involvement of additional cognitive processes that are not present during unimodal paradigms.

text: An ERP N400 study: Semantic processing across modalities in the human brain Semantic processing in the brain of both language and action has been associated with the N400; an event-related potential (ERP) that is typically present when information has violated one’s semantic expectations. We know that the brain receives and processes information from multiple modalities which means that cross-modal semantic processing is more aligned with how semantic processing is likely to occur in comparison to unimodal semantic processing. The N400 is a consistent effect across cross-modal language-based studies. But we know that the topographical distribution of the N400 does vary between language-based and non-language-based paradigms. Therefore, to investigate cross-modal semantic processing within the action domain, we presented participants with photographs portraying the implementation of common actions. These sequences concluded with a sound that was either congruent or incongruent with the prior action photographs. In our ERP study of 25 participants, with a mean age of 23 years (SD = 10.78 years), we¹ found an N400 effect for incongruent information processing. In addition, our findings showed a delayed N400 effect and a reduced P200 amplitude for incongruent information. These results suggest that cross-modal semantic processing of action sequences requires an increased cognitive workload which is evidenced when semantic processing does not progress as expected. Considered as a whole, these results indicate that cross-modal semantic processing is similar to unimodal processing. Cross-modal information likely requires the involvement of additional cognitive processes that are not present during unimodal paradigms.

year: 2023

title: Māori Goddesses in Literature Part 1: pre 1880 - 1900

authors: Yates-Smith, Aroha

subjects: Atua wāhine

abstract: Many contemporary Māori are familiar with atua wāhine, Māori goddesses, through accounts that have been passed on to them by word of mouth. Few, however, have had an opportunity to consult accounts of atua wāhine that date from the early period of Māori-Pākehā contact. Those who wish to do so may have considerable difficulty in sifting through all of the written materials for the information they seek. For this reason, this paper provides a review of the literature pertaining to atua wāhine from pre-1880 to 1900, together with a commentary on the sources to which reference is made. A review of literature on atua wāhine which appeared after 1900 will appear in the second volume of this journal.

text: Māori Goddesses in Literature Part 1: pre 1880 - 1900 Many contemporary Māori are familiar with atua wāhine, Māori goddesses, through accounts that have been passed on to them by word of mouth. Few, however, have had an opportunity to consult accounts of atua wāhine that date from the early period of Māori-Pākehā contact. Those who wish to do so may have considerable difficulty in sifting through all of the written materials for the information they seek. For this reason, this paper provides a review of the literature pertaining to atua wāhine from pre-1880 to 1900, together with a commentary on the sources to which reference is made. A review of literature on atua wāhine which appeared after 1900 will appear in the second volume of this journal.

year: 2000-10