title: Compression by induction of hierarchical grammars

authors: Nevill-Manning, Craig G.

subjects: Machine learning

abstract: This paper describes a technique that develops models of symbol sequences in the form of small, human-readable, hierarchical grammars. The grammars are both semantically plausible and compact. The technique can induce structure from a variety of different kinds of sequence, and examples are given of models derived from English text, C source code and a file of numeric data. This paper explains the grammatical induction technique, demonstrates its application to three very different sequences, evaluates its compression performance, and concludes by briefly discussing its use as method of knowledge acquisition.

text: Compression by induction of hierarchical grammars This paper describes a technique that develops models of symbol sequences in the form of small, human-readable, hierarchical grammars. The grammars are both semantically plausible and compact. The technique can induce structure from a variety of different kinds of sequence, and examples are given of models derived from English text, C source code and a file of numeric data. This paper explains the grammatical induction technique, demonstrates its application to three very different sequences, evaluates its compression performance, and concludes by briefly discussing its use as method of knowledge acquisition.

year: 1993

title: General Anaesthetic Modulation of Memory-Related Gene Expression Using an In vitro Brain Slice Model

authors: Stayte, Liam Thomas Oliver

subjects: General Anaesthetic

abstract: General anaesthetics cause widespread neurochemical and physiological changes in the brain. However, the precise mechanism of amnesic action is largely unknown. Gene expression changes in the hippocampus have been a focal point for investigation in this area, while effects on the cerebral cortex have been largely underreported even though the cerebral cortex has been shown to play a large role in memory consolidation and storage. Amnesia is likely due to the change in expression of memory-related genes within the neocortex or hippocampus of the mammalian brain. 

The first aim of this research was to investigate the in vitro cortical gene expression pattern of two memory-related genes; activity-regulated cytoskeleton-associated protein (Arc) and brain-derived neurotrophic factor (Bdnf), after a t=4 hour exposure to propofol- or sevoflurane- induced anaesthesia using an adult mouse brain slice model and real-time quantitative PCR. Five animals were used for each anaesthetic and a t=0 hour control, t=4 hour control and t=4 hour treated 400 μm slice were taken from each animal. Seizure-like activity was recorded from the brain slices to ensure viability of the tissue before carrying out the anaesthetic exposure. RNA was extracted, DNAse-treated, and then converted to cDNA. Quantitative PCR was then carried out to analyse Bdnf and Arc expression differences between the t=4 hour control and t=4 hour treated samples using Gapdh, β2m, Actb and HRPT1 as reference genes. The second research aim was to determine the Bdnf protein expression level and localisation after a t=4 hour exposure to propofol using western blot and immunohistochemistry methodologies.

Our research demonstrated that Arc was significantly down-regulated after exposure to sevoflurane for t=4 hours (p<0.05). Arc was also shown to be up-regulated after a t=4 hour exposure to propofol while Bdnf showed a downregulation to sevoflurane but an upregulation to propofol, however this data was not statistically significant. Western blot data showed that the rabbit polyclonal Bdnf antibody was binding to an off-target epitope at 55 kDa with mouse brain, heart, lung, liver, spleen and kidney whole tissue lysate. A newly sourced commercial Bdnf antibody was validated and western blot data showed recognition of the Bdnf epitope at the correct predicted size of 28 kDa in the mouse brain, heart and kidney. Immunohistochemistry of frozen mouse brain sections failed to produce a positive signal for two different Bdnf antibodies due to encountering technical issues. Hematoxylin and Eosin staining showed the tissue was still intact after the sectioning procedure. These issues could be resolved in the future by improving the tissue fixation length and optimising the antigen retrieval step. 

Eleven recommendations have been made to provide further insight into the gene expression levels of memory-related genes in the mouse brain. This includes varying the induction and maintenance of the two anaesthetic drugs, role of epigenetic modification, evaluating the mental state of the mice (depression), investigating Bdnf knockout, differential expression between areas of the brain and brain electrical activity. In addition, the gene expression pattern after a period of anaesthetic exposure should also be analysed. This may help elucidate the causes of postoperative cognitive dysfunction. Whole transcriptome analysis using RNA-Seq could be used to determine the expression levels of other known memory-related genes after anaesthetic exposure.

text: General Anaesthetic Modulation of Memory-Related Gene Expression Using an In vitro Brain Slice Model General anaesthetics cause widespread neurochemical and physiological changes in the brain. However, the precise mechanism of amnesic action is largely unknown. Gene expression changes in the hippocampus have been a focal point for investigation in this area, while effects on the cerebral cortex have been largely underreported even though the cerebral cortex has been shown to play a large role in memory consolidation and storage. Amnesia is likely due to the change in expression of memory-related genes within the neocortex or hippocampus of the mammalian brain. 

The first aim of this research was to investigate the in vitro cortical gene expression pattern of two memory-related genes; activity-regulated cytoskeleton-associated protein (Arc) and brain-derived neurotrophic factor (Bdnf), after a t=4 hour exposure to propofol- or sevoflurane- induced anaesthesia using an adult mouse brain slice model and real-time quantitative PCR. Five animals were used for each anaesthetic and a t=0 hour control, t=4 hour control and t=4 hour treated 400 μm slice were taken from each animal. Seizure-like activity was recorded from the brain slices to ensure viability of the tissue before carrying out the anaesthetic exposure. RNA was extracted, DNAse-treated, and then converted to cDNA. Quantitative PCR was then carried out to analyse Bdnf and Arc expression differences between the t=4 hour control and t=4 hour treated samples using Gapdh, β2m, Actb and HRPT1 as reference genes. The second research aim was to determine the Bdnf protein expression level and localisation after a t=4 hour exposure to propofol using western blot and immunohistochemistry methodologies.

Our research demonstrated that Arc was significantly down-regulated after exposure to sevoflurane for t=4 hours (p<0.05). Arc was also shown to be up-regulated after a t=4 hour exposure to propofol while Bdnf showed a downregulation to sevoflurane but an upregulation to propofol, however this data was not statistically significant. Western blot data showed that the rabbit polyclonal Bdnf antibody was binding to an off-target epitope at 55 kDa with mouse brain, heart, lung, liver, spleen and kidney whole tissue lysate. A newly sourced commercial Bdnf antibody was validated and western blot data showed recognition of the Bdnf epitope at the correct predicted size of 28 kDa in the mouse brain, heart and kidney. Immunohistochemistry of frozen mouse brain sections failed to produce a positive signal for two different Bdnf antibodies due to encountering technical issues. Hematoxylin and Eosin staining showed the tissue was still intact after the sectioning procedure. These issues could be resolved in the future by improving the tissue fixation length and optimising the antigen retrieval step. 

Eleven recommendations have been made to provide further insight into the gene expression levels of memory-related genes in the mouse brain. This includes varying the induction and maintenance of the two anaesthetic drugs, role of epigenetic modification, evaluating the mental state of the mice (depression), investigating Bdnf knockout, differential expression between areas of the brain and brain electrical activity. In addition, the gene expression pattern after a period of anaesthetic exposure should also be analysed. This may help elucidate the causes of postoperative cognitive dysfunction. Whole transcriptome analysis using RNA-Seq could be used to determine the expression levels of other known memory-related genes after anaesthetic exposure.

year: 2016

title: Kūpapa ki raro, titiro ake

authors: Papa, Pānia Christine

abstract: Ko tā te kaituhi e manako nei i roto i tēnei tuhinga, kia āta tirohia he aha ngā huarahi i whāia ai e ngā iwi o Pōhara, hei kawe i a rātou mai i te pōharatanga ki te oranga tonutanga; mai i te noho marara ki te noho tahi; mai i te korekore ki te ao mārama. Ko te tuarua o ngā pātai kei mua i taku aroaro, he wānanga mena i tutuki pai ngā kaupapa i wawatahia ai e rātou. 
E rua ngā kōrero matua e toko ake ana i roto i ahau hei taumarumaru mō ngā whakaaro me ngā kōrero kua whakatakotoria i te tuhinga nei, hei whakautu i ngā pātai matua e rua ō runga ake nei. 
Tuatahi, 'Ko te amorangi ki mua, ko te hāpai ō ki muri'. E hāngai ana tēnei whakataukī ki te pūmautanga o ngā whakaaro o ngā tūpuna o Pōhara ki ngā kaupapa i kōkirihia ai e tō rātou rangatira, me te āhua o tā ngā tūpuna hāpai i aua kaupapa. I te tīmatanga, nā Piupiu Te Wherowhero rātou i arataki. I te rā nei, ko Te Arikinui, Te Atairangikaahu te manu whakataka pōkai i te ata hāpara, e ngāngahu tonu nei i ngā iwi o te marae o Pōhara. 
Tuarua, 'Kūpapa ki raro, Titiro ake.' Koia tēnei tētehi whakataukī whakahau i ngā uri whakatupu o te marae, o Pōhara, kua waihotia e rātou mā hei kupu ārahi i ngā uri i runga i te marae, i roto anō hoki i te ao hou. He hōhonutanga anō tō te whakataukī nei e tika ana kia whakamāramahia i roto i tēnei tuhinga, hei whāki atu i ngā rerenga kētanga o te āhua o te whakaaro o kui mā, o koro mā, me te āhua o tā rātou noho i te wā i a rātou. 
Ko te whakatau o ngā kōrero, i tutuki pai i ngā tūpuna o te marae o Pōhara ō rātou manako, nā tō rātou kaha ū ki te kaupapa o te Kāhui Ariki, me tō rātou ū ki te kaupapa o te tupuranga o te papakāinga o Pōhara hei marae mō ngā uri whakatupu. Ka noho mai tērā hei whakatohu i tō rātou pakaritanga, me ō rātou whakaaro rangatira hei tauira mā ngā uri whakaheke e whai ake ana i ngā tapuwae o ngā tūpuna. 
Ko ēnei tuhinga hei whakatinana i te ngākau nui kia waituhia ngā kōrero ā ngā rūruhi, ā ngā koroheke, mō te marae o Pōhara, kei ngaro katoa atu ngēnā kōrero e here nei i te ao kōhatu ki te ao hou. 
Nā te ngākau māhaki o ngā kaumātua i whakaae ai kia tuhia te kaupapa nei, kia puta ai ngā kōrero mō Pōhara ki te ao mārama hei painga mō ngā uri whakatupu. Nā rātou i whakatūwhera te kūaha ki tō rātou ao hei kuhu atu ki roto mā te hunga mahira. Ko ngā kongakonga kōrero i taka iho mai i ō rātou puna mahara, kua kohia-ā-rīpenehia hei taonga tuku iho mō ngā iwi o te marae. E tika ana kia puruhia te mauri o ērā kōrero e ngā whānau me ngā uri o te marae. 
I tutuki ai te taha rangahau i ngā kōrero kaumātua i te whakatū wānanga, me te uiui kaumātua. I whāia ngā huarahi e rua nei hei kohikohi i ngā kōrero-ā-waha mō te hītori o Pōhara. Arā noa atu ngā painga i kitea, o te noho tahi a ngā kaumātua i runga tonu i te marae, ki te whakawhitiwhiti whakaaro, kōrero hoki mō ngā rā o mua i waenganui i a rātou. Ā, hei whai ake i ngā kōrero i puta i ngā wānanga, i haere māua ko taku matua ki te torotoro i tēnā, i tēnā o ngā kaumātua e mōhio pai ana ki ngā kōrero, hei whakakīkī i ngā whārua, hei whakawhānui hoki i ngā kōrero. I ngāwari ake taku mahi i te haere tahitanga mai o taku matua, hei hoa mōku. Ko tāna, he āta whakamārama atu i te pūtake o te rangahau, he whakamārama hoki i te whakaaetanga o ngā kaumātua ki tērā mahi. I mōhio pai hoki ia ki ngā kōrero whānui mō te marae, ki ngā tāngata ka kōrerohia, ā, nā konā i taea e ia te whiu atu ētehi pātai, te whakamārama hoki i ahau i muri mai mō te āhua o ētehi o ngā kōrero kāore i tino mārama mai ki ahau. I tū hoki taku matua hei piriti i waenganui i te kaikōrero kaumātua me te kaiuiui rangatahi kia whakawhiti pai ai ngā pātai me ngā whakautu ki waenganui i ngā taha e rua. Koia tērā taku waimarie i roto i ngā mahi uiui kaumātua, ā, koia hoki i tutuki pai ai tērā taha o te rangahau. 
I tae mai ki aku ringa tētehi rīpene o tētehi wānanga i hopukina ai i te tau 1978. Nō taua tau, i haere ake ētehi akonga o te Tari Māori o Te Whare Wānanga o Waikato, i raro i te maru o Wharehuia Milroy ki te rapu i ngā kōrero mō te marae o Pōhara. Heoi anō, i tō rātou hokinga atu ki te kāinga, kāore te nuinga o ngā kōrero i hopukina. Ka waihotia te take nā kia tārewa, ā, tae rawa ki te tau 1990, kātahi ka riro i ahau te rīpene kotahi i ora mai, hei āwhina i aku mahi rangahau mō tōku marae. 
I rapu māramatanga ahau mō te āhua o te noho a te iwi Māori whānui i ngā rā o mua, i roto i ngā pukapuka maha kua tuhia kētia. Mō ngā kōrero mō te whenua e tū nei te marae ināianei, i haere ki te Kooti Whenua Māori, ki reira kimi ai i ngā kōrero mō te rohe o Maungatautari whānui, mō te marae o Pōhara hoki. Nā ēnei whaiwhainga, kua puta he kōrero, kua puta hoki he whakaaro hei whakawā i ērā kōrero, hei whakamārama rānei i ērā kōrero, ā, koia tēnei e takoto nei i roto i tēnei tuhinga. Ka huri ināianei ki te wetewetetanga o ngā wāhanga o roto i te tuhinga nei. 
Nō namata mai anō i tīkina atu ai te rākau i te Wao-nui-ā-Tāne hei tārai i te waka o ōku tūpuna. Tēnei au e tiki atu nei i te rākau hei tauira hanga kōrero mōku. Ko tō te rākau tupu, ki ngā whakaaro o tēnei e tuhi nei, e pērā ana ki te tupu o te kaupapa kia nohoia te marae o Pōhara e tū ana i raro i te maru o Maungatautari. 
Arā noa atu ngā tauritenga o te tupu o te rākau me tō te marae o Pōhara tupu, mai i ōna pūtakenga hei papakāinga, ki te puāwaitanga o te whakaaro kia tū hei marae mō te mokopuna a te motu, mō ngā uri whakatupu, otirā, mō te iwi whānui. 
E whitu anō ngā wāhanga o tō te rākau tupu e whakatauritehia nei i roto i ngā whārangi o tēnei tuhinga. Ko te whenua tonu hei papa mō te tupu o te rākau, mō te tupu hoki o te marae Nō reira, ka tīmata ake i konā.

text: Kūpapa ki raro, titiro ake Ko tā te kaituhi e manako nei i roto i tēnei tuhinga, kia āta tirohia he aha ngā huarahi i whāia ai e ngā iwi o Pōhara, hei kawe i a rātou mai i te pōharatanga ki te oranga tonutanga; mai i te noho marara ki te noho tahi; mai i te korekore ki te ao mārama. Ko te tuarua o ngā pātai kei mua i taku aroaro, he wānanga mena i tutuki pai ngā kaupapa i wawatahia ai e rātou. 
E rua ngā kōrero matua e toko ake ana i roto i ahau hei taumarumaru mō ngā whakaaro me ngā kōrero kua whakatakotoria i te tuhinga nei, hei whakautu i ngā pātai matua e rua ō runga ake nei. 
Tuatahi, 'Ko te amorangi ki mua, ko te hāpai ō ki muri'. E hāngai ana tēnei whakataukī ki te pūmautanga o ngā whakaaro o ngā tūpuna o Pōhara ki ngā kaupapa i kōkirihia ai e tō rātou rangatira, me te āhua o tā ngā tūpuna hāpai i aua kaupapa. I te tīmatanga, nā Piupiu Te Wherowhero rātou i arataki. I te rā nei, ko Te Arikinui, Te Atairangikaahu te manu whakataka pōkai i te ata hāpara, e ngāngahu tonu nei i ngā iwi o te marae o Pōhara. 
Tuarua, 'Kūpapa ki raro, Titiro ake.' Koia tēnei tētehi whakataukī whakahau i ngā uri whakatupu o te marae, o Pōhara, kua waihotia e rātou mā hei kupu ārahi i ngā uri i runga i te marae, i roto anō hoki i te ao hou. He hōhonutanga anō tō te whakataukī nei e tika ana kia whakamāramahia i roto i tēnei tuhinga, hei whāki atu i ngā rerenga kētanga o te āhua o te whakaaro o kui mā, o koro mā, me te āhua o tā rātou noho i te wā i a rātou. 
Ko te whakatau o ngā kōrero, i tutuki pai i ngā tūpuna o te marae o Pōhara ō rātou manako, nā tō rātou kaha ū ki te kaupapa o te Kāhui Ariki, me tō rātou ū ki te kaupapa o te tupuranga o te papakāinga o Pōhara hei marae mō ngā uri whakatupu. Ka noho mai tērā hei whakatohu i tō rātou pakaritanga, me ō rātou whakaaro rangatira hei tauira mā ngā uri whakaheke e whai ake ana i ngā tapuwae o ngā tūpuna. 
Ko ēnei tuhinga hei whakatinana i te ngākau nui kia waituhia ngā kōrero ā ngā rūruhi, ā ngā koroheke, mō te marae o Pōhara, kei ngaro katoa atu ngēnā kōrero e here nei i te ao kōhatu ki te ao hou. 
Nā te ngākau māhaki o ngā kaumātua i whakaae ai kia tuhia te kaupapa nei, kia puta ai ngā kōrero mō Pōhara ki te ao mārama hei painga mō ngā uri whakatupu. Nā rātou i whakatūwhera te kūaha ki tō rātou ao hei kuhu atu ki roto mā te hunga mahira. Ko ngā kongakonga kōrero i taka iho mai i ō rātou puna mahara, kua kohia-ā-rīpenehia hei taonga tuku iho mō ngā iwi o te marae. E tika ana kia puruhia te mauri o ērā kōrero e ngā whānau me ngā uri o te marae. 
I tutuki ai te taha rangahau i ngā kōrero kaumātua i te whakatū wānanga, me te uiui kaumātua. I whāia ngā huarahi e rua nei hei kohikohi i ngā kōrero-ā-waha mō te hītori o Pōhara. Arā noa atu ngā painga i kitea, o te noho tahi a ngā kaumātua i runga tonu i te marae, ki te whakawhitiwhiti whakaaro, kōrero hoki mō ngā rā o mua i waenganui i a rātou. Ā, hei whai ake i ngā kōrero i puta i ngā wānanga, i haere māua ko taku matua ki te torotoro i tēnā, i tēnā o ngā kaumātua e mōhio pai ana ki ngā kōrero, hei whakakīkī i ngā whārua, hei whakawhānui hoki i ngā kōrero. I ngāwari ake taku mahi i te haere tahitanga mai o taku matua, hei hoa mōku. Ko tāna, he āta whakamārama atu i te pūtake o te rangahau, he whakamārama hoki i te whakaaetanga o ngā kaumātua ki tērā mahi. I mōhio pai hoki ia ki ngā kōrero whānui mō te marae, ki ngā tāngata ka kōrerohia, ā, nā konā i taea e ia te whiu atu ētehi pātai, te whakamārama hoki i ahau i muri mai mō te āhua o ētehi o ngā kōrero kāore i tino mārama mai ki ahau. I tū hoki taku matua hei piriti i waenganui i te kaikōrero kaumātua me te kaiuiui rangatahi kia whakawhiti pai ai ngā pātai me ngā whakautu ki waenganui i ngā taha e rua. Koia tērā taku waimarie i roto i ngā mahi uiui kaumātua, ā, koia hoki i tutuki pai ai tērā taha o te rangahau. 
I tae mai ki aku ringa tētehi rīpene o tētehi wānanga i hopukina ai i te tau 1978. Nō taua tau, i haere ake ētehi akonga o te Tari Māori o Te Whare Wānanga o Waikato, i raro i te maru o Wharehuia Milroy ki te rapu i ngā kōrero mō te marae o Pōhara. Heoi anō, i tō rātou hokinga atu ki te kāinga, kāore te nuinga o ngā kōrero i hopukina. Ka waihotia te take nā kia tārewa, ā, tae rawa ki te tau 1990, kātahi ka riro i ahau te rīpene kotahi i ora mai, hei āwhina i aku mahi rangahau mō tōku marae. 
I rapu māramatanga ahau mō te āhua o te noho a te iwi Māori whānui i ngā rā o mua, i roto i ngā pukapuka maha kua tuhia kētia. Mō ngā kōrero mō te whenua e tū nei te marae ināianei, i haere ki te Kooti Whenua Māori, ki reira kimi ai i ngā kōrero mō te rohe o Maungatautari whānui, mō te marae o Pōhara hoki. Nā ēnei whaiwhainga, kua puta he kōrero, kua puta hoki he whakaaro hei whakawā i ērā kōrero, hei whakamārama rānei i ērā kōrero, ā, koia tēnei e takoto nei i roto i tēnei tuhinga. Ka huri ināianei ki te wetewetetanga o ngā wāhanga o roto i te tuhinga nei. 
Nō namata mai anō i tīkina atu ai te rākau i te Wao-nui-ā-Tāne hei tārai i te waka o ōku tūpuna. Tēnei au e tiki atu nei i te rākau hei tauira hanga kōrero mōku. Ko tō te rākau tupu, ki ngā whakaaro o tēnei e tuhi nei, e pērā ana ki te tupu o te kaupapa kia nohoia te marae o Pōhara e tū ana i raro i te maru o Maungatautari. 
Arā noa atu ngā tauritenga o te tupu o te rākau me tō te marae o Pōhara tupu, mai i ōna pūtakenga hei papakāinga, ki te puāwaitanga o te whakaaro kia tū hei marae mō te mokopuna a te motu, mō ngā uri whakatupu, otirā, mō te iwi whānui. 
E whitu anō ngā wāhanga o tō te rākau tupu e whakatauritehia nei i roto i ngā whārangi o tēnei tuhinga. Ko te whenua tonu hei papa mō te tupu o te rākau, mō te tupu hoki o te marae Nō reira, ka tīmata ake i konā.

year: 1997