title: Comparison of changes in electroencephalographic measures during induction of general anaesthesia: influence of the gamma frequency band and electromyogram signal

authors: Sleigh, James W.

subjects: monitoring

abstract: Recent research has shown that high-frequency, gamma-band electroencephalographic (EEG) oscillations (40–60 Hz) may be an important marker of the conscious state. We compared the ability of the bispectral index (BIS) to distinguish the awake and anaesthetized states during the induction of general anaesthesia with: (i) components of the BIS (BetaRatio, SynchFastSlow); (ii) a new EEG variable—the median frequency of the first time derivative of the EEG signal (SE50d); and (iii) the SE50d derived from an EEG signal that has had the frequencies above 30 Hz removed (SE50d30Hz). Two groups of subjects were studied: (i) nine volunteers undergoing a short propofol infusion until loss of response to verbal command, and (ii) 84 patients undergoing routine anaesthesia for a variety of surgical procedures. In the volunteer group, the changes in the BetaRatio and SE50d were comparable with changes in the BIS. The changes in the SE50d30Hz were less consistent. In the patient group, the BIS components were equivalent to the BIS in separating the awake from the surgically anaesthetized states (area under receiver operating curve: BIS 0.95, SE50d 0.95, BetaRatio 0.96). Using the submental electromyogram (EMG) signal to estimate the frontalis EMG (30–47 Hz) signal, the changes in EMG signal were, on average, about one-tenth the magnitude of the EEG. We conclude that: (i) there exist simpler derived EEG variables that are similar in accuracy to the BIS; (ii) it is important to avoid filtering out the EEG frequencies above 30 Hz; and (iii) in most patients the confounding effects of the frontalis EMG on the EEG are minimal.

text: Comparison of changes in electroencephalographic measures during induction of general anaesthesia: influence of the gamma frequency band and electromyogram signal Recent research has shown that high-frequency, gamma-band electroencephalographic (EEG) oscillations (40–60 Hz) may be an important marker of the conscious state. We compared the ability of the bispectral index (BIS) to distinguish the awake and anaesthetized states during the induction of general anaesthesia with: (i) components of the BIS (BetaRatio, SynchFastSlow); (ii) a new EEG variable—the median frequency of the first time derivative of the EEG signal (SE50d); and (iii) the SE50d derived from an EEG signal that has had the frequencies above 30 Hz removed (SE50d30Hz). Two groups of subjects were studied: (i) nine volunteers undergoing a short propofol infusion until loss of response to verbal command, and (ii) 84 patients undergoing routine anaesthesia for a variety of surgical procedures. In the volunteer group, the changes in the BetaRatio and SE50d were comparable with changes in the BIS. The changes in the SE50d30Hz were less consistent. In the patient group, the BIS components were equivalent to the BIS in separating the awake from the surgically anaesthetized states (area under receiver operating curve: BIS 0.95, SE50d 0.95, BetaRatio 0.96). Using the submental electromyogram (EMG) signal to estimate the frontalis EMG (30–47 Hz) signal, the changes in EMG signal were, on average, about one-tenth the magnitude of the EEG. We conclude that: (i) there exist simpler derived EEG variables that are similar in accuracy to the BIS; (ii) it is important to avoid filtering out the EEG frequencies above 30 Hz; and (iii) in most patients the confounding effects of the frontalis EMG on the EEG are minimal.

year: 2001

title: A bag of oranges and a communal lunch: Intra-action of matter and becoming

authors: Kotzé, Elmarie

abstract: In the chapter the author draws on new materialism and poststructuralism to write about becoming-subject. The author uses the notions of fluidity of the self, the (im)possibility of writing self and, at the same time, productive self-writing in the spaces between humans and between humans and nonhumans. She uses two encounters from her childhood to illustrate entanglements that highlight the ongoing production of becoming in the intra-relations between children and adults and between humans and the more-than-human vehicle-food-trees-snuffbox. The discursive Bmaterial encounters fold into and diffract out of her teaching and supervision practices in a counselling program in Aotearoa, New Zealand.

text: A bag of oranges and a communal lunch: Intra-action of matter and becoming In the chapter the author draws on new materialism and poststructuralism to write about becoming-subject. The author uses the notions of fluidity of the self, the (im)possibility of writing self and, at the same time, productive self-writing in the spaces between humans and between humans and nonhumans. She uses two encounters from her childhood to illustrate entanglements that highlight the ongoing production of becoming in the intra-relations between children and adults and between humans and the more-than-human vehicle-food-trees-snuffbox. The discursive Bmaterial encounters fold into and diffract out of her teaching and supervision practices in a counselling program in Aotearoa, New Zealand.

year: 2018

title: Mana whenua, mana tangata: Raukawa ake, Raukawa iho

authors: Peni, Tamati

subjects: Raukawa

abstract: Mā te whakapapa, ngā tohu whenua, ngā pae whenua, ngā mātākōrero, ngā kōrero tuku iho, ka whakatere te takenga mai o ngā ariā me ngā mātāpono o Raukawa.  Ina te matapakinga, ka tīkaro hoki i ngā āhuatanga o tuawhakarere me ngā āhuatanga o te ao hurihuri kia tūhono i ngā matapakinga he aha rānei te Raukawatanga me te pātai he aha hoki ōna pānga ki te ao whai muri ake i te taunaha i ngā take Tiriti.  Nā te whānui rawa me te kaha tīni haere o te taiwhanga nei, ka whakawhāiti te rangahau ki ngā whakamautanga o Raukawa ki ngā pae whenua tawhito, ā, ka whītikihia te aronga ki nāianei, ki te ao hurihuri.

I seek to explore the ideological grounding of Raukawa through whakapapa, land marks, boundaries, oral history, and tradition.  Through this, a simultaneous extraction of traditional and contemporary themes are used to bridge new and old ways of being and what impact this has on being Raukawa in a post-settlement setting.  Because of the vastness and changing nature of this environment, I narrow my focus to how Raukawa maintained traditional boundaries and draw on its relevance to modern Raukawa development today.

text: Mana whenua, mana tangata: Raukawa ake, Raukawa iho Mā te whakapapa, ngā tohu whenua, ngā pae whenua, ngā mātākōrero, ngā kōrero tuku iho, ka whakatere te takenga mai o ngā ariā me ngā mātāpono o Raukawa.  Ina te matapakinga, ka tīkaro hoki i ngā āhuatanga o tuawhakarere me ngā āhuatanga o te ao hurihuri kia tūhono i ngā matapakinga he aha rānei te Raukawatanga me te pātai he aha hoki ōna pānga ki te ao whai muri ake i te taunaha i ngā take Tiriti.  Nā te whānui rawa me te kaha tīni haere o te taiwhanga nei, ka whakawhāiti te rangahau ki ngā whakamautanga o Raukawa ki ngā pae whenua tawhito, ā, ka whītikihia te aronga ki nāianei, ki te ao hurihuri.

I seek to explore the ideological grounding of Raukawa through whakapapa, land marks, boundaries, oral history, and tradition.  Through this, a simultaneous extraction of traditional and contemporary themes are used to bridge new and old ways of being and what impact this has on being Raukawa in a post-settlement setting.  Because of the vastness and changing nature of this environment, I narrow my focus to how Raukawa maintained traditional boundaries and draw on its relevance to modern Raukawa development today.

year: 2013