title: What happens to diet and child health when migration splits households? Evidence from a migration lottery program

authors: Gibson, John

subjects: migration

abstract: The impact of migration on food security and child health is likely to differ depending on whether children themselves migrate or whether they remain behind while other household members migrate. However, existing studies have not been able to examine how impacts differ in these two scenarios because parallel data are required for both the sending and receiving country. Moreover, self-selection into migration makes unbiased estimation of either impact difficult. We overcome these problems by using a unique survey of Tongan households that applied to migrate to New Zealand through a migrant quota which selects households through a random ballot. This survey covers both migrant children in New Zealand and non-migrant children in Tonga, with the migration policy rules providing a source of exogenous variation for identifying impacts. Our estimates of short-run impacts show that diets diverge upon migration: children who migrate experience improvements, while diets worsen for children who remain. There is also suggestive evidence of a divergence in health outcomes, with increases in weight-for-age and height-for-age found for migrant children, and decreases found for children who remain behind while other household members migrate.

text: What happens to diet and child health when migration splits households? Evidence from a migration lottery program The impact of migration on food security and child health is likely to differ depending on whether children themselves migrate or whether they remain behind while other household members migrate. However, existing studies have not been able to examine how impacts differ in these two scenarios because parallel data are required for both the sending and receiving country. Moreover, self-selection into migration makes unbiased estimation of either impact difficult. We overcome these problems by using a unique survey of Tongan households that applied to migrate to New Zealand through a migrant quota which selects households through a random ballot. This survey covers both migrant children in New Zealand and non-migrant children in Tonga, with the migration policy rules providing a source of exogenous variation for identifying impacts. Our estimates of short-run impacts show that diets diverge upon migration: children who migrate experience improvements, while diets worsen for children who remain. There is also suggestive evidence of a divergence in health outcomes, with increases in weight-for-age and height-for-age found for migrant children, and decreases found for children who remain behind while other household members migrate.

year: 2010

title: A structural basis for the reduced toxicity of dinophysistoxin-2

authors: Huhn, Jason

subjects: dinophysistoxin

abstract: Okadaic acid (OA), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2) are algal toxins that can accumulate in shellfish and cause diarrhetic shellfish poisoning. Recent studies indicate that DTX-2 is about half as toxic and has about half the affinity for protein phosphatase 2A (PP2A) as OA. NMR structural studies showed that DTX-1 possessed an equatorial 35-methyl group but that DTX-2 had an axial 35-methyl group. Molecular modeling studies indicated that an axial 35-methyl could exhibit unfavorable interactions in the PP2A binding site, and this has been proposed as the reason for the reduced toxicity of DTX-2. Statistical analyses of published data indicate that the affinity of PP2A for DTX-1 is 1.6-fold higher, and for DTX-2 is 2-fold lower, than for OA. We obtained X-ray crystal structures of DTX-1 and DTX-2 bound to PP2A. The crystal structures independently confirm the C-35 stereochemistries determined in the earlier NMR study. The structure for the DTX-1 complex was virtually identical to that of the OA-PP2A complex, except for the presence of the equatorial 35-methyl on the ligand. The favorable placement of the equatorial 35-methyl group of DTX-1 against the aromatic π-bonds of His191 may account for the increased affinity of PP2A toward DTX-1. In contrast, the axial 35-methyl of DTX-2 caused the side chain of His191 to rotate 140° so that it pointed toward the solvent, thereby opening one end of the hydrophobic binding cage. This rearrangement to accommodate the unfavorable interaction from the axial 35-methyl of DTX-2 reduces the binding energy and appears to be responsible for the reduced affinity of PP2A for DTX-2. These results highlight the potential of molecular modeling studies for understanding the relative toxicity of analogues once the binding site at the molecular target has been properly characterized.

text: A structural basis for the reduced toxicity of dinophysistoxin-2 Okadaic acid (OA), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2) are algal toxins that can accumulate in shellfish and cause diarrhetic shellfish poisoning. Recent studies indicate that DTX-2 is about half as toxic and has about half the affinity for protein phosphatase 2A (PP2A) as OA. NMR structural studies showed that DTX-1 possessed an equatorial 35-methyl group but that DTX-2 had an axial 35-methyl group. Molecular modeling studies indicated that an axial 35-methyl could exhibit unfavorable interactions in the PP2A binding site, and this has been proposed as the reason for the reduced toxicity of DTX-2. Statistical analyses of published data indicate that the affinity of PP2A for DTX-1 is 1.6-fold higher, and for DTX-2 is 2-fold lower, than for OA. We obtained X-ray crystal structures of DTX-1 and DTX-2 bound to PP2A. The crystal structures independently confirm the C-35 stereochemistries determined in the earlier NMR study. The structure for the DTX-1 complex was virtually identical to that of the OA-PP2A complex, except for the presence of the equatorial 35-methyl on the ligand. The favorable placement of the equatorial 35-methyl group of DTX-1 against the aromatic π-bonds of His191 may account for the increased affinity of PP2A toward DTX-1. In contrast, the axial 35-methyl of DTX-2 caused the side chain of His191 to rotate 140° so that it pointed toward the solvent, thereby opening one end of the hydrophobic binding cage. This rearrangement to accommodate the unfavorable interaction from the axial 35-methyl of DTX-2 reduces the binding energy and appears to be responsible for the reduced affinity of PP2A for DTX-2. These results highlight the potential of molecular modeling studies for understanding the relative toxicity of analogues once the binding site at the molecular target has been properly characterized.

year: 2009

title: Te kaumoana Poronīhia: Ngā terenga onamata

authors: Tuaupiki, Jackie Whetumarama

subjects: Kōrero nehe

abstract: Tā tēnei tuhinga e whai ake nei, he wānanga i ngā pūtake o te whanaketanga mai o ngā iwi, nāna ngā motu o Poronīhia i whakakāinga, ka utaina te karangatanga ki runga ki a rātou, he iwi Poronīhia. Ko te pātai matua, i ahu mai ngā iwi Poronīhia i whea? Tēnei, ka hahaina ngā whakaaro Māori me ngā whakaaro Tauiwi e pā ana ki te pūtakenga mai o te iwi tāngata ki te ao. I konei, ka kitea te rerekē o te titiro ā-ao a ēnei iwi tāngata.

Ka ū te titiro ki Hawaiki, e tau ana ngā kōrero tuku iho a te ao Māori, ki te ao Poronīhia hoki. E mea ana te Māori, he tūrangawaewae taurikura a Hawaiki, he pā whakawairua hoki. Ka riariakina e au ngā whakapae mō tēnei karangatanga kāinga i mau roa ai i ōna iwi kōrero.

Ka huri rā ki te āta whakatewhatewha i ngā rangahau mō te horanga haeretanga o te iwi tāngata mai i whirika, ki  hia ki te tonga mā rāwhiti, ā, tau atu rā ki roto i ngā whaitua moana o Poronīhia. I konei, kua āta wānangahia e au ngā whakapae huhua mō ngā take i horapa haere ai ēnei iwi ki roto o Poronīhia, ka tahi. Ka rua, ka tirohia ngā tohe e pā ana ki tō rātou āheinga ki te whakatere i ō rātou waka. Ko ēnei kōrero, he whakatuwhera i te pūtea mātauranga mō runga i ngā mahi whakatere waka a ngā tūpuna Poronīhia.

text: Te kaumoana Poronīhia: Ngā terenga onamata Tā tēnei tuhinga e whai ake nei, he wānanga i ngā pūtake o te whanaketanga mai o ngā iwi, nāna ngā motu o Poronīhia i whakakāinga, ka utaina te karangatanga ki runga ki a rātou, he iwi Poronīhia. Ko te pātai matua, i ahu mai ngā iwi Poronīhia i whea? Tēnei, ka hahaina ngā whakaaro Māori me ngā whakaaro Tauiwi e pā ana ki te pūtakenga mai o te iwi tāngata ki te ao. I konei, ka kitea te rerekē o te titiro ā-ao a ēnei iwi tāngata.

Ka ū te titiro ki Hawaiki, e tau ana ngā kōrero tuku iho a te ao Māori, ki te ao Poronīhia hoki. E mea ana te Māori, he tūrangawaewae taurikura a Hawaiki, he pā whakawairua hoki. Ka riariakina e au ngā whakapae mō tēnei karangatanga kāinga i mau roa ai i ōna iwi kōrero.

Ka huri rā ki te āta whakatewhatewha i ngā rangahau mō te horanga haeretanga o te iwi tāngata mai i whirika, ki  hia ki te tonga mā rāwhiti, ā, tau atu rā ki roto i ngā whaitua moana o Poronīhia. I konei, kua āta wānangahia e au ngā whakapae huhua mō ngā take i horapa haere ai ēnei iwi ki roto o Poronīhia, ka tahi. Ka rua, ka tirohia ngā tohe e pā ana ki tō rātou āheinga ki te whakatere i ō rātou waka. Ko ēnei kōrero, he whakatuwhera i te pūtea mātauranga mō runga i ngā mahi whakatere waka a ngā tūpuna Poronīhia.

year: 2017