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Costas Meghir - One of the best experts on this subject based on the ideXlab platform.
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using the infrastructure of a conditional cash transfer Program to deliver a scalable integrated early child development Program in colombia cluster randomized controlled trial
BMJ, 2014Co-Authors: Orazio Attanasio, Costas Meghir, Camila Fernandez, Emla Fitzsimons, Sally Granthammcgregor, Marta Rubio CodinaAbstract:Objective To assess the effectiveness of an integrated early child development intervention, combining stimulation and micronutrient supplementation and delivered on a large scale in Colombia, for children’s development, growth, and hemoglobin levels. Design Cluster randomized controlled trial, using a 2×2 factorial design, with municipalities assigned to one of four groups: psychosocial stimulation, micronutrient supplementation, combined intervention, or control. Setting 96 municipalities in Colombia, located across eight of its 32 departments. Participants 1420 children aged 12-24 months and their primary carers. Intervention Psychosocial stimulation (weekly home visits with play demonstrations), micronutrient sprinkles given daily, and both combined. All delivered by female community leaders for 18 months. Main outcome measures Cognitive, receptive and expressive language, and fine and gross motor scores on the Bayley scales of infant development-III; height, weight, and hemoglobin levels measured at the baseline and end of intervention. Results Stimulation improved cognitive scores (adjusted for age, sex, testers, and baseline levels of outcomes) by 0.26 of a standard deviation (P=0.002). Stimulation also increased receptive language by 0.22 of a standard deviation (P=0.032). Micronutrient supplementation had no significant effect on any outcome and there was no interaction between the interventions. No intervention affected height, weight, or hemoglobin levels. Conclusions Using the infrastructure of a national Welfare Program we implemented the integrated early child development intervention on a large scale and showed its potential for improving children’s cognitive development. We found no effect of supplementation on developmental or health outcomes. Moreover, supplementation did not interact with stimulation. The implementation model for delivering stimulation suggests that it may serve as a promising blueprint for future policy on early childhood development. Trial registration Current Controlled trials ISRCTN18991160.
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labor supply models unobserved heterogeneity nonparticipation and dynamics
Handbook of Econometrics, 2007Co-Authors: Richard Blundell, Thomas E. Macurdy, Costas MeghirAbstract:This chapter is concerned with the identification and estimation of models of labor supply. The focus is on the key issues that arise from unobserved heterogeneity, nonparticipation and dynamics. We examine the simple "static" labor supply model with proportional taxes and highlight the problems surrounding nonparticipation and missing wages. The difference-in-differences approach to estimation and identification is developed within the context of the labor supply model. We also consider the impact of incorporating nonlinear taxation and Welfare Program participation. Family labor supply is looked at from both the unitary and collective perspectives. Finally we consider intertemporal models focusing on the difficulties that arise with participation and heterogeneity.
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chapter 69 labor supply models unobserved heterogeneity nonparticipation and dynamics
Handbook of Econometrics, 2007Co-Authors: Richard Blundell, Thomas E. Macurdy, Costas MeghirAbstract:Abstract This chapter is concerned with the identification and estimation of models of labor supply. The focus is on the key issues that arise from unobserved heterogeneity, nonparticipation and dynamics. We examine the simple “static” labor supply model with proportional taxes and highlight the problems surrounding nonparticipation and missing wages. The difference-in-differences approach to estimation and identification is developed within the context of the labor supply model. We also consider the impact of incorporating nonlinear taxation and Welfare Program participation. Family labor supply is looked at from both the unitary and collective perspectives. Finally we consider intertemporal models focusing on the difficulties that arise with participation and heterogeneity.
Evans, David J. - One of the best experts on this subject based on the ideXlab platform.
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Green Bees : Reverse Genetic Analysis of Deformed Wing Virus Transmission, Replication, and Tropism
'MDPI AG', 2020Co-Authors: Gusachenko, Olesya N., Woodford Luke, Balbirnie-cumming Katharin, Campbell, Ewan M., Christie, Craig R., Bowman, Alan S., Evans, David J.Abstract:Funding: This work was supported by grant funding from Biotechnology and Biological Sciences Research Council (BBSRC): BBSRC BB/M00337X/2 and BB/I000828/1. C.R.C. was supported by a KTN BBSRC CASE studentship BB/M503526/1 (http://www.bbsrc.ac.uk). C.R.C was part-funded by the Scottish Beekeeping Association (https://www.scottishbeekeepers.org.uk/) and the Animal Health and Welfare Program by the Scottish Government. E.M.C. was supported by the Veterinary Medicines Directorate, Department for Environment Food & Rural Affairs (Project # VM0517) (https://www.gov.uk/government/organisations/veterinary-medicines-directorate). Acknowledgments: We would like to express our gratitude to Robert J Paxton (Martin Luther University Halle-Wittenberg) for providing a reference sequence for the construction of DWV-B RG system, Marcus Bischoff and Gill McVee (University of St Andrews) for helping with microscopic imaging set up, Javier Tello (University of St Andrews) for help and advice on sample cryosectioning, Ivan Gusachenko (University of St Andrews) for obtaining a photo of EGFP-expressing pupa, Ashley Pearson (University of St Andrews) for assistance in molecular biology assays, and Kirsten Bentley (University of St Andrews) for the high practical and moral support throughout the project.Peer reviewedPublisher PD
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Green bees : reverse genetic analysis of deformed wing virus transmission, replication, and tropism
'MDPI AG', 2020Co-Authors: Gusachenko, Olesya N., Woodford Luke, Balbirnie-cumming Katharin, Campbell, Ewan M., Christie, Craig R., Bowman, Alan S., Evans, David J.Abstract:This work was supported by grant funding from Biotechnology and Biological Sciences Research Council (BBSRC): BBSRC BB/M00337X/2 and BB/I000828/1. C.R.C. was supported by a KTN BBSRC CASE studentship BB/M503526/1 (http://www.bbsrc.ac.uk). C.R.C was part-funded by the Scottish Beekeeping Association (https://www.scottishbeekeepers.org.uk/) and the Animal Health and Welfare Program by the Scottish Government. E.M.C. was supported by the Veterinary Medicines Directorate, Department for Environment Food & Rural Affairs (Project # VM0517) (https://www.gov.uk/government/organisations/veterinary-medicines-directorate).Environmental and agricultural pollination services by honey bees, Apis mellifera, and honey production are compromised by high levels of annual colony losses globally. The majority are associated with disease caused by deformed wing virus (DWV), a positive-strand RNA virus, exacerbated by the ectoparasitic mite Varroa destructor. To improve honey bee health, a better understanding of virus transmission and pathogenesis is needed which requires the development of tools to study virus replication, transmission, and localisation. We report the use of reverse genetic (RG) systems for the predominant genetically distinct variants of DWV to address these questions. All RG-recovered viruses replicate within 24 h post-inoculation of pupae and could recapitulate the characteristic symptoms of DWV disease upon eclosion. Larvae were significantly less susceptible but could be infected orally and subsequently developed disease. Using genetically tagged RG DWV and an in vitro Varroa feeding system, we demonstrate virus replication in the mite by accumulation of tagged negative-strand viral replication intermediates. We additionally apply a modified DWV genome expressing a fluorescent reporter protein for direct in vivo observation of virus distribution in injected pupae or fed larvae. Using this, we demonstrate extensive sites of virus replication in a range of pupal tissues and organs and in the nascent wing buds in larvae fed high levels of virus, indicative of a direct association between virus replication and pathogenesis. These studies provide insights into virus replication kinetics, tropism, transmission, and pathogenesis, and produce new tools to help develop the understanding needed to control DWV-mediated colony losses.Publisher PDFPeer reviewe
Gusachenko, Olesya N. - One of the best experts on this subject based on the ideXlab platform.
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Green Bees : Reverse Genetic Analysis of Deformed Wing Virus Transmission, Replication, and Tropism
'MDPI AG', 2020Co-Authors: Gusachenko, Olesya N., Woodford Luke, Balbirnie-cumming Katharin, Campbell, Ewan M., Christie, Craig R., Bowman, Alan S., Evans, David J.Abstract:Funding: This work was supported by grant funding from Biotechnology and Biological Sciences Research Council (BBSRC): BBSRC BB/M00337X/2 and BB/I000828/1. C.R.C. was supported by a KTN BBSRC CASE studentship BB/M503526/1 (http://www.bbsrc.ac.uk). C.R.C was part-funded by the Scottish Beekeeping Association (https://www.scottishbeekeepers.org.uk/) and the Animal Health and Welfare Program by the Scottish Government. E.M.C. was supported by the Veterinary Medicines Directorate, Department for Environment Food & Rural Affairs (Project # VM0517) (https://www.gov.uk/government/organisations/veterinary-medicines-directorate). Acknowledgments: We would like to express our gratitude to Robert J Paxton (Martin Luther University Halle-Wittenberg) for providing a reference sequence for the construction of DWV-B RG system, Marcus Bischoff and Gill McVee (University of St Andrews) for helping with microscopic imaging set up, Javier Tello (University of St Andrews) for help and advice on sample cryosectioning, Ivan Gusachenko (University of St Andrews) for obtaining a photo of EGFP-expressing pupa, Ashley Pearson (University of St Andrews) for assistance in molecular biology assays, and Kirsten Bentley (University of St Andrews) for the high practical and moral support throughout the project.Peer reviewedPublisher PD
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Green bees : reverse genetic analysis of deformed wing virus transmission, replication, and tropism
'MDPI AG', 2020Co-Authors: Gusachenko, Olesya N., Woodford Luke, Balbirnie-cumming Katharin, Campbell, Ewan M., Christie, Craig R., Bowman, Alan S., Evans, David J.Abstract:This work was supported by grant funding from Biotechnology and Biological Sciences Research Council (BBSRC): BBSRC BB/M00337X/2 and BB/I000828/1. C.R.C. was supported by a KTN BBSRC CASE studentship BB/M503526/1 (http://www.bbsrc.ac.uk). C.R.C was part-funded by the Scottish Beekeeping Association (https://www.scottishbeekeepers.org.uk/) and the Animal Health and Welfare Program by the Scottish Government. E.M.C. was supported by the Veterinary Medicines Directorate, Department for Environment Food & Rural Affairs (Project # VM0517) (https://www.gov.uk/government/organisations/veterinary-medicines-directorate).Environmental and agricultural pollination services by honey bees, Apis mellifera, and honey production are compromised by high levels of annual colony losses globally. The majority are associated with disease caused by deformed wing virus (DWV), a positive-strand RNA virus, exacerbated by the ectoparasitic mite Varroa destructor. To improve honey bee health, a better understanding of virus transmission and pathogenesis is needed which requires the development of tools to study virus replication, transmission, and localisation. We report the use of reverse genetic (RG) systems for the predominant genetically distinct variants of DWV to address these questions. All RG-recovered viruses replicate within 24 h post-inoculation of pupae and could recapitulate the characteristic symptoms of DWV disease upon eclosion. Larvae were significantly less susceptible but could be infected orally and subsequently developed disease. Using genetically tagged RG DWV and an in vitro Varroa feeding system, we demonstrate virus replication in the mite by accumulation of tagged negative-strand viral replication intermediates. We additionally apply a modified DWV genome expressing a fluorescent reporter protein for direct in vivo observation of virus distribution in injected pupae or fed larvae. Using this, we demonstrate extensive sites of virus replication in a range of pupal tissues and organs and in the nascent wing buds in larvae fed high levels of virus, indicative of a direct association between virus replication and pathogenesis. These studies provide insights into virus replication kinetics, tropism, transmission, and pathogenesis, and produce new tools to help develop the understanding needed to control DWV-mediated colony losses.Publisher PDFPeer reviewe
Richard Blundell - One of the best experts on this subject based on the ideXlab platform.
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labor supply models unobserved heterogeneity nonparticipation and dynamics
Handbook of Econometrics, 2007Co-Authors: Richard Blundell, Thomas E. Macurdy, Costas MeghirAbstract:This chapter is concerned with the identification and estimation of models of labor supply. The focus is on the key issues that arise from unobserved heterogeneity, nonparticipation and dynamics. We examine the simple "static" labor supply model with proportional taxes and highlight the problems surrounding nonparticipation and missing wages. The difference-in-differences approach to estimation and identification is developed within the context of the labor supply model. We also consider the impact of incorporating nonlinear taxation and Welfare Program participation. Family labor supply is looked at from both the unitary and collective perspectives. Finally we consider intertemporal models focusing on the difficulties that arise with participation and heterogeneity.
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chapter 69 labor supply models unobserved heterogeneity nonparticipation and dynamics
Handbook of Econometrics, 2007Co-Authors: Richard Blundell, Thomas E. Macurdy, Costas MeghirAbstract:Abstract This chapter is concerned with the identification and estimation of models of labor supply. The focus is on the key issues that arise from unobserved heterogeneity, nonparticipation and dynamics. We examine the simple “static” labor supply model with proportional taxes and highlight the problems surrounding nonparticipation and missing wages. The difference-in-differences approach to estimation and identification is developed within the context of the labor supply model. We also consider the impact of incorporating nonlinear taxation and Welfare Program participation. Family labor supply is looked at from both the unitary and collective perspectives. Finally we consider intertemporal models focusing on the difficulties that arise with participation and heterogeneity.
Ian Walker - One of the best experts on this subject based on the ideXlab platform.
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the labour supply unemployment and participation of lone mothers in in work transfer Programmes
The Economic Journal, 1997Co-Authors: Paul Bingley, Ian WalkerAbstract:In-work transfer schemes have recently been suggested as a device for encouraging labor force participation and reducing the severity of the disincentives associated with out-of-work income support schemes. Here the authors estimate a discrete choice labor supply model which allows for endogenous in-work Welfare Program participation. They also allow for involuntary unemployment so as to distinguish between Program nonparticipation and an inability to obtain work and thereby generate an eligibility to the Program. Copyright 1997 by Royal Economic Society.
