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  • Open Access English
    Authors: 
    Kains, N.; Bramich, D. M.; Arellano Ferro, A.; Figuera Jaimes, R.; Jørgensen, U. G.; Giridhar, S.; Penny, M. T.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; +41 more

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  • Publication . Article . Other literature type . 2017
    Open Access
    Authors: 
    Sanja Stanojevic; Stephanie D. Davis; George Z. Retsch-Bogart; Hailey Webster; Miriam Davis; Robin Johnson; Renee Jensen; Maria Ester Pizarro; Mica Kane; Charles Clem; +3 more
    Publisher: American Thoracic Society

    Rationale: Implementation of intervention strategies to prevent lung damage in early cystic fibrosis (CF) requires objective outcome measures that capture and track lung disease.Objectives: To define the utility of the Lung Clearance Index (LCI), measured by multiple breath washout, as a means to track disease progression in preschool children with CF.Methods: Children with CF between the ages of 2.5 and 6 years with a confirmed diagnosis of CF and age-matched healthy control subjects were enrolled at three North American CF centers. Multiple breath washout tests were performed at baseline, 1, 3, 6, and 12 months to mimic time points chosen in clinical care and interventional trials; spirometry was also conducted. A generalized linear mixed-effects model was used to distinguish LCI changes associated with normal growth and development (i.e., healthy children) from the progression of CF lung disease.Measurements and Main Results: Data were collected on 156 participants with 800 LCI measurements. Although b...

  • Open Access
    Authors: 
    F. Guerrero; Jocelyn Bouchard; Éric Poulin; Daniel Sbarbaro;
    Publisher: Elsevier BV

    Abstract: Real-time simulation plays an important role not only in the design and commissioning of new control strategies, but also in training the operators before the actual system is installed. There are in the market several simulation environments for carrying out these tasks. However, there is still a need of having more flexible environments that can be easily integrated with other systems and tools such as real-time optimization and advanced data analysis. In this work, several standard tools such as Simulink®/Simulink®, OPC toolbox, RSLogix 5000, and FactoryTalk® are integrated to simulate a control strategy for a SAG mill designed to keep the mill operating in the stable region by manipulating the fresh ore feed. The implementation of this strategy is based on standard control blocks available in the ControlLogix Programmable Logic Controllers (PLCs). Experimental results show the effectiveness of the proposed approach to integrate standard tools, and open new possibilities for further developments in the design of advanced monitoring and control strategies for industrial processes.

  • Open Access
    Authors: 
    Georges Aad; Leszek Adamczyk; Jahred Adelman; Tim Adye; Tatjana Agatonovic-Jovin; J. A. Aguilar-Saavedra; Faig Ahmadov; Giulio Aielli; Gian Luigi Alberghi; J. Albert; +599 more
    Publisher: American Physical Society (APS)
    Project: NSERC

    Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at root s = 8 TeV corresponding to an integrated luminosity of 20.3 fb(-1) collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios.

  • Open Access English
    Authors: 
    Gregory J. Dore; Brian Conway; Yan Luo; Ewa Janczewska; Brygida Knysz; Y. Liu; Adrian Streinu-Cercel; Florin Alexandru Caruntu; Manuela Curescu; Richard Skoien; +16 more
    Publisher: The Authors. Published by Elsevier B.V.

    Background & AimsTelaprevir plus pegylated interferon/ribavirin (TPV+PegIFN/RBV) remains a therapeutic option for chronic hepatitis C virus (HCV) genotype (GT) 1 infection in many regions. We conducted two open-label, phase IIIb trials comparing safety and efficacy of all-oral ombitasvir/paritaprevir/ritonavir and dasabuvir±ribavirin (OBV/PTV/r+DSV±RBV) and TPV+PegIFN/RBV.MethodsTreatment-naïve (MALACHITE-I) or PegIFN/RBV-experienced (MALACHITE-II) non-cirrhotic, chronic HCV GT1-infected patients were randomized to OBV/PTV/r+DSV+weight-based RBV, OBV/PTV/r+DSV (treatment-naïve, GT1b-infected patients only), or 12weeks of TPV+PegIFN+weight-based RBV and 12–36 additional weeks of PegIFN/RBV. The primary endpoint was sustained virologic response 12weeks post-treatment (SVR12). Patient-reported outcome questionnaires evaluated mental and physical health during the studies.ResultsThree hundred eleven treatment-naïve and 148 treatment-experienced patients were randomized and dosed. Among treatment-naïve patients, SVR12 rates were 97% (67/69) and 82% (28/34), respectively, in OBV/PTV/r+DSV+RBV and TPV+PegIFN/RBV-treated GT1a-infected patients; SVR12 rates were 99% (83/84), 98% (81/83), and 78% (32/41) in OBV/PTV/r+DSV+RBV, OBV/PTV/r+DSV, and TPV+PegIFN/RBV-treated GT1b-infected patients. Among treatment-experienced patients, SVR12 rates were 99% (100/101) and 66% (31/47) with OBV/PTV/r+DSV+RBV and TPV+PegIFN/RBV. Mental and physical health were generally better with OBV/PTV/r+DSV±RBV than TPV+PegIFN/RBV. Rates of discontinuation due to adverse events (0–1% and 8–11%, respectively, p<0.05) and rates of hemoglobin decline to <10g/dl (0–4% and 34–47%, respectively, p<0.05) were lower for OBV/PTV/r+DSV±RBV than TPV+PegIFN/RBV.ConclusionsAmong non-cirrhotic, HCV GT1-infected patients, SVR12 rates were 97–99% with 12week, multi-targeted OBV/PTV/r+DSV±RBV regimens and 66–82% with 24–48 total weeks of TPV+PegIFN/RBV. OBV/PTV/r+DSV±RBV was associated with a generally better mental and physical health, more favorable tolerability, and lower rates of treatment discontinuation due to adverse events.

  • Open Access
    Authors: 
    Koraljka Mužić; Alexander Scholz; Karla Peña Ramírez; Ray Jayawardhana; Rainer Schödel; Vincent Geers; Lucas A. Cieza; Amelia Bayo;
    Publisher: American Astronomical Society
    Countries: Spain, United Kingdom
    Project: FCT | PTDC/FIS-AST/28731/2017 (PTDC/FIS-AST/28731/2017), NSERC , EC | GALACTICNUCLEUS (614922), UKRI | Astronomy at St Andrews 2... (ST/R000824/1)

    As part of the ongoing effort to characterize the low-mass (sub)stellar population in a sample of massive young clusters, we have targeted the ∼2 Myr old cluster NGC 2244. The distance to NGC 2244 from Gaia DR2 parallaxes is 1.59 kpc, with errors of 1% (statistical) and 11% (systematic). We used the Flamingos-2 near-infrared camera at the Gemini-South telescope for deep multi-band imaging of the central portion of the cluster (∼2.4 pc). We determined membership in a statistical manner, through a comparison of the cluster's color-magnitude diagram to that of a control field. Masses and extinctions of the candidate members are then calculated with the help of evolutionary models, leading to the first initial mass function (IMF) of the cluster extending into the substellar regime, with the 90% completeness limit around 0.02 M . The IMF is well represented by a broken power law (dN/dM ∝ M ) with a break at ∼0.4 M . The slope on the high-mass side (0.4-7 M ) is α = 2.12 ±0.08, close to the standard Salpeter slope. In the low-mass range (0.02-0.4 M ), we find a slope α = 1.03 ±0.02, which is at the high end of the typical values obtained in nearby star-forming regions (α = 0.5-1.0), but still in agreement within the uncertainties. Our results reveal no clear evidence for variations in the formation efficiency of brown dwarfs (BDs) and very low-mass stars due to the presence of OB stars, or for a change in stellar densities. Our finding rules out photoevaporation and fragmentation of infalling filaments as substantial pathways for BD formation.© 2019. The American Astronomical Society. All rights reserved. K.M. acknowledges funding by the Science and Technology Foundation of Portugal (FCT), grants No. IF/00194/2015 and PTDC/FIS-AST/28731/2017. Part of the research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework program (FP7/2007-2013)/ERC grant agreement No. [614922]. R.J. acknowledges support from NSERC grants. A. S.' s work is supported by the STFC grant No. ST/R000824/1. L.C. acknowledges support from CONICYT-FONDECYT grant No. 1171246. K.P.R. acknowledges CONICYT PAI Concurso Nacional de Insercion en la Academia, Convocatoria 2016 Folio PAI79160052. This research has made use of the Spanish Virtual Observatory (http://svo.cab.inta-csic.es) supported from the Spanish MINECO/FEDER through grant AYA2014-55216. Peer Reviewed

  • Publication . Article . 2012
    Open Access
    Authors: 
    Cheng Cheng; Taibin Du; Xialing Guan;
    Publisher: Elsevier BV

    Abstract The Compact Pulsed Hadron Source (CPHS) system has been proposed and designed by the Department of Engineering Physics of Tsinghua University in Beijing, China. It consists of an accelerator front-end—a highintensity ion source, a 3 MeV radiofrequency quadrupole linac (RFQ), and a 13 MeV drift-tube linac (DTL), a neutron target station, and some experimental stations. In design of our RF power supply, both RFQ and DTL share a single klystron which is capable of 2.5 MW peak RF power and a 3.33% duty factor. The 325 MHz klystron contains a modulating anode and has a 100 kW average output power. Portions of the RF power system, such as pulsed high voltage power supply, modulator, crowbar protection and RF power transmission are all presented in details in this paper.

  • Open Access English
    Authors: 
    Ruth Danzeisen; Magdalena Araya; Brenda Harrison; Carl L. Keen; Marc Solioz; Dennis J. Thiele; Harry J. McArdle;
    Publisher: Cambridge University Press
    Country: Switzerland

    The response by Brewer & Althaus to our recent review on biomarkers for Cu(1) bears testimony that the subject is topical and of public, scientific and commercial interest.

  • Publication . Article . 2008
    Open Access
    Authors: 
    Juan Antonio Carrasco; Eric J. Miller; Barry Wellman;
    Publisher: SAGE Publications

    Hägerstrand's seminal argument that regional science is about people and not just locations is still a compelling and challenging idea when the spatial distribution of activities is studied. In the context of social activity–travel behavior (hosting and visiting), this issue is particularly fundamental as individuals’ main motivation in making social trips is mostly with whom they interact rather than where they go. A useful approach to incorporate the travelers’ social context is to study explicitly the spatial distribution of their social networks, focusing on social locations as emerging from their contacts, rather than analyzing social activity locations in isolation. In this context, this paper studies the spatial distribution of social activities, focusing on the home distances between specific individuals (egos) and the network members (alters) with whom they socialize—serving as a proxy to study social activity–travel location. Using data from a recent study of personal networks and social interaction, and multilevel models that account for the hierarchical structure of these networks, this paper provides empirical evidence on how the characteristics of individuals and their social context relate to the distance separating them. The results strongly suggest that, although the spatial distribution of social interaction has idiosyncratic characteristics, there are several systematic effects associated with the characteristics of egos, alters, and their personal networks that affect the spatial distribution of relationships, and they can contribute to an understanding of where people perform social activities with others.

  • Open Access
    Authors: 
    Schellenberg, D; Armstrong Schellenberg, J R M; Mushi, A; Savigny de, D; Mgalula, L; Mbuya, C; Victoria, C.G.;
    Country: Tanzania (United Republic of)

    Objective was to document the prevalence, age-distribution, and risk factors for anaemia in Tanzanian children less than 5 years old,thereby assisting in the development of effective strategies for controlling anaemia. Cluster sampling was used to identify 2417 households at random from four contiguous districts in south-eastern United Republic of Tanzania in mid-1999. Data on various social and medical parameters were collected and analysed. Blood haemoglobin concentrations (Hb) were available for 1979 of the 2131 (93%) children identified and ranged from 1.7 to 18.6 g/dl. Overall, 87% (1722) of children had an Hb <11 g/dl, 39% (775) had an Hb <8 g/dl and 3% (65) had an Hb <5 g/dl. The highest prevalence of anaemia of all three levels was in children aged 6–11 months, of whom 10% (22/226) had an Hb <5 g/dl. However, the prevalence of anaemia was already high in children aged 1–5 months (85% had an Hb <11 g/dl, 42% had an Hb <8 g/dl, and 6% had an Hb <5 g/dl). Anaemia was usually asymptomatic and when symptoms arose they were nonspecific and rarely identified as a serious illness by the care provider. A recent history of treatment with antimalarials and iron was rare. Compliance with vaccinations delivered through the Expanded Programme of Immunization (EPI) was 82% and was notassociated with risk of anaemia. Anaemia is extremely common in south-eastern United Republic of Tanzania, even in very young infants. Further implementation of the Integrated Management of Childhood Illness algorithm should improve the case management of anaemia. However, the asymptomatic nature of most episodes of anaemia highlights the need for preventive strategies. The EPI has good coverage of the target population and it may be an appropriate channel for delivering tools for controlling anaemia and malaria.

search
Include:
The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
5,971 Research products, page 1 of 598
  • Open Access English
    Authors: 
    Kains, N.; Bramich, D. M.; Arellano Ferro, A.; Figuera Jaimes, R.; Jørgensen, U. G.; Giridhar, S.; Penny, M. T.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; +41 more

    Not Available

  • Publication . Article . Other literature type . 2017
    Open Access
    Authors: 
    Sanja Stanojevic; Stephanie D. Davis; George Z. Retsch-Bogart; Hailey Webster; Miriam Davis; Robin Johnson; Renee Jensen; Maria Ester Pizarro; Mica Kane; Charles Clem; +3 more
    Publisher: American Thoracic Society

    Rationale: Implementation of intervention strategies to prevent lung damage in early cystic fibrosis (CF) requires objective outcome measures that capture and track lung disease.Objectives: To define the utility of the Lung Clearance Index (LCI), measured by multiple breath washout, as a means to track disease progression in preschool children with CF.Methods: Children with CF between the ages of 2.5 and 6 years with a confirmed diagnosis of CF and age-matched healthy control subjects were enrolled at three North American CF centers. Multiple breath washout tests were performed at baseline, 1, 3, 6, and 12 months to mimic time points chosen in clinical care and interventional trials; spirometry was also conducted. A generalized linear mixed-effects model was used to distinguish LCI changes associated with normal growth and development (i.e., healthy children) from the progression of CF lung disease.Measurements and Main Results: Data were collected on 156 participants with 800 LCI measurements. Although b...

  • Open Access
    Authors: 
    F. Guerrero; Jocelyn Bouchard; Éric Poulin; Daniel Sbarbaro;
    Publisher: Elsevier BV

    Abstract: Real-time simulation plays an important role not only in the design and commissioning of new control strategies, but also in training the operators before the actual system is installed. There are in the market several simulation environments for carrying out these tasks. However, there is still a need of having more flexible environments that can be easily integrated with other systems and tools such as real-time optimization and advanced data analysis. In this work, several standard tools such as Simulink®/Simulink®, OPC toolbox, RSLogix 5000, and FactoryTalk® are integrated to simulate a control strategy for a SAG mill designed to keep the mill operating in the stable region by manipulating the fresh ore feed. The implementation of this strategy is based on standard control blocks available in the ControlLogix Programmable Logic Controllers (PLCs). Experimental results show the effectiveness of the proposed approach to integrate standard tools, and open new possibilities for further developments in the design of advanced monitoring and control strategies for industrial processes.

  • Open Access
    Authors: 
    Georges Aad; Leszek Adamczyk; Jahred Adelman; Tim Adye; Tatjana Agatonovic-Jovin; J. A. Aguilar-Saavedra; Faig Ahmadov; Giulio Aielli; Gian Luigi Alberghi; J. Albert; +599 more
    Publisher: American Physical Society (APS)
    Project: NSERC

    Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at root s = 8 TeV corresponding to an integrated luminosity of 20.3 fb(-1) collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios.

  • Open Access English
    Authors: 
    Gregory J. Dore; Brian Conway; Yan Luo; Ewa Janczewska; Brygida Knysz; Y. Liu; Adrian Streinu-Cercel; Florin Alexandru Caruntu; Manuela Curescu; Richard Skoien; +16 more
    Publisher: The Authors. Published by Elsevier B.V.

    Background & AimsTelaprevir plus pegylated interferon/ribavirin (TPV+PegIFN/RBV) remains a therapeutic option for chronic hepatitis C virus (HCV) genotype (GT) 1 infection in many regions. We conducted two open-label, phase IIIb trials comparing safety and efficacy of all-oral ombitasvir/paritaprevir/ritonavir and dasabuvir±ribavirin (OBV/PTV/r+DSV±RBV) and TPV+PegIFN/RBV.MethodsTreatment-naïve (MALACHITE-I) or PegIFN/RBV-experienced (MALACHITE-II) non-cirrhotic, chronic HCV GT1-infected patients were randomized to OBV/PTV/r+DSV+weight-based RBV, OBV/PTV/r+DSV (treatment-naïve, GT1b-infected patients only), or 12weeks of TPV+PegIFN+weight-based RBV and 12–36 additional weeks of PegIFN/RBV. The primary endpoint was sustained virologic response 12weeks post-treatment (SVR12). Patient-reported outcome questionnaires evaluated mental and physical health during the studies.ResultsThree hundred eleven treatment-naïve and 148 treatment-experienced patients were randomized and dosed. Among treatment-naïve patients, SVR12 rates were 97% (67/69) and 82% (28/34), respectively, in OBV/PTV/r+DSV+RBV and TPV+PegIFN/RBV-treated GT1a-infected patients; SVR12 rates were 99% (83/84), 98% (81/83), and 78% (32/41) in OBV/PTV/r+DSV+RBV, OBV/PTV/r+DSV, and TPV+PegIFN/RBV-treated GT1b-infected patients. Among treatment-experienced patients, SVR12 rates were 99% (100/101) and 66% (31/47) with OBV/PTV/r+DSV+RBV and TPV+PegIFN/RBV. Mental and physical health were generally better with OBV/PTV/r+DSV±RBV than TPV+PegIFN/RBV. Rates of discontinuation due to adverse events (0–1% and 8–11%, respectively, p<0.05) and rates of hemoglobin decline to <10g/dl (0–4% and 34–47%, respectively, p<0.05) were lower for OBV/PTV/r+DSV±RBV than TPV+PegIFN/RBV.ConclusionsAmong non-cirrhotic, HCV GT1-infected patients, SVR12 rates were 97–99% with 12week, multi-targeted OBV/PTV/r+DSV±RBV regimens and 66–82% with 24–48 total weeks of TPV+PegIFN/RBV. OBV/PTV/r+DSV±RBV was associated with a generally better mental and physical health, more favorable tolerability, and lower rates of treatment discontinuation due to adverse events.

  • Open Access
    Authors: 
    Koraljka Mužić; Alexander Scholz; Karla Peña Ramírez; Ray Jayawardhana; Rainer Schödel; Vincent Geers; Lucas A. Cieza; Amelia Bayo;
    Publisher: American Astronomical Society
    Countries: Spain, United Kingdom
    Project: FCT | PTDC/FIS-AST/28731/2017 (PTDC/FIS-AST/28731/2017), NSERC , EC | GALACTICNUCLEUS (614922), UKRI | Astronomy at St Andrews 2... (ST/R000824/1)

    As part of the ongoing effort to characterize the low-mass (sub)stellar population in a sample of massive young clusters, we have targeted the ∼2 Myr old cluster NGC 2244. The distance to NGC 2244 from Gaia DR2 parallaxes is 1.59 kpc, with errors of 1% (statistical) and 11% (systematic). We used the Flamingos-2 near-infrared camera at the Gemini-South telescope for deep multi-band imaging of the central portion of the cluster (∼2.4 pc). We determined membership in a statistical manner, through a comparison of the cluster's color-magnitude diagram to that of a control field. Masses and extinctions of the candidate members are then calculated with the help of evolutionary models, leading to the first initial mass function (IMF) of the cluster extending into the substellar regime, with the 90% completeness limit around 0.02 M . The IMF is well represented by a broken power law (dN/dM ∝ M ) with a break at ∼0.4 M . The slope on the high-mass side (0.4-7 M ) is α = 2.12 ±0.08, close to the standard Salpeter slope. In the low-mass range (0.02-0.4 M ), we find a slope α = 1.03 ±0.02, which is at the high end of the typical values obtained in nearby star-forming regions (α = 0.5-1.0), but still in agreement within the uncertainties. Our results reveal no clear evidence for variations in the formation efficiency of brown dwarfs (BDs) and very low-mass stars due to the presence of OB stars, or for a change in stellar densities. Our finding rules out photoevaporation and fragmentation of infalling filaments as substantial pathways for BD formation.© 2019. The American Astronomical Society. All rights reserved. K.M. acknowledges funding by the Science and Technology Foundation of Portugal (FCT), grants No. IF/00194/2015 and PTDC/FIS-AST/28731/2017. Part of the research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework program (FP7/2007-2013)/ERC grant agreement No. [614922]. R.J. acknowledges support from NSERC grants. A. S.' s work is supported by the STFC grant No. ST/R000824/1. L.C. acknowledges support from CONICYT-FONDECYT grant No. 1171246. K.P.R. acknowledges CONICYT PAI Concurso Nacional de Insercion en la Academia, Convocatoria 2016 Folio PAI79160052. This research has made use of the Spanish Virtual Observatory (http://svo.cab.inta-csic.es) supported from the Spanish MINECO/FEDER through grant AYA2014-55216. Peer Reviewed

  • Publication . Article . 2012
    Open Access
    Authors: 
    Cheng Cheng; Taibin Du; Xialing Guan;
    Publisher: Elsevier BV

    Abstract The Compact Pulsed Hadron Source (CPHS) system has been proposed and designed by the Department of Engineering Physics of Tsinghua University in Beijing, China. It consists of an accelerator front-end—a highintensity ion source, a 3 MeV radiofrequency quadrupole linac (RFQ), and a 13 MeV drift-tube linac (DTL), a neutron target station, and some experimental stations. In design of our RF power supply, both RFQ and DTL share a single klystron which is capable of 2.5 MW peak RF power and a 3.33% duty factor. The 325 MHz klystron contains a modulating anode and has a 100 kW average output power. Portions of the RF power system, such as pulsed high voltage power supply, modulator, crowbar protection and RF power transmission are all presented in details in this paper.

  • Open Access English
    Authors: 
    Ruth Danzeisen; Magdalena Araya; Brenda Harrison; Carl L. Keen; Marc Solioz; Dennis J. Thiele; Harry J. McArdle;
    Publisher: Cambridge University Press
    Country: Switzerland

    The response by Brewer & Althaus to our recent review on biomarkers for Cu(1) bears testimony that the subject is topical and of public, scientific and commercial interest.

  • Publication . Article . 2008
    Open Access
    Authors: 
    Juan Antonio Carrasco; Eric J. Miller; Barry Wellman;
    Publisher: SAGE Publications

    Hägerstrand's seminal argument that regional science is about people and not just locations is still a compelling and challenging idea when the spatial distribution of activities is studied. In the context of social activity–travel behavior (hosting and visiting), this issue is particularly fundamental as individuals’ main motivation in making social trips is mostly with whom they interact rather than where they go. A useful approach to incorporate the travelers’ social context is to study explicitly the spatial distribution of their social networks, focusing on social locations as emerging from their contacts, rather than analyzing social activity locations in isolation. In this context, this paper studies the spatial distribution of social activities, focusing on the home distances between specific individuals (egos) and the network members (alters) with whom they socialize—serving as a proxy to study social activity–travel location. Using data from a recent study of personal networks and social interaction, and multilevel models that account for the hierarchical structure of these networks, this paper provides empirical evidence on how the characteristics of individuals and their social context relate to the distance separating them. The results strongly suggest that, although the spatial distribution of social interaction has idiosyncratic characteristics, there are several systematic effects associated with the characteristics of egos, alters, and their personal networks that affect the spatial distribution of relationships, and they can contribute to an understanding of where people perform social activities with others.

  • Open Access
    Authors: 
    Schellenberg, D; Armstrong Schellenberg, J R M; Mushi, A; Savigny de, D; Mgalula, L; Mbuya, C; Victoria, C.G.;
    Country: Tanzania (United Republic of)

    Objective was to document the prevalence, age-distribution, and risk factors for anaemia in Tanzanian children less than 5 years old,thereby assisting in the development of effective strategies for controlling anaemia. Cluster sampling was used to identify 2417 households at random from four contiguous districts in south-eastern United Republic of Tanzania in mid-1999. Data on various social and medical parameters were collected and analysed. Blood haemoglobin concentrations (Hb) were available for 1979 of the 2131 (93%) children identified and ranged from 1.7 to 18.6 g/dl. Overall, 87% (1722) of children had an Hb <11 g/dl, 39% (775) had an Hb <8 g/dl and 3% (65) had an Hb <5 g/dl. The highest prevalence of anaemia of all three levels was in children aged 6–11 months, of whom 10% (22/226) had an Hb <5 g/dl. However, the prevalence of anaemia was already high in children aged 1–5 months (85% had an Hb <11 g/dl, 42% had an Hb <8 g/dl, and 6% had an Hb <5 g/dl). Anaemia was usually asymptomatic and when symptoms arose they were nonspecific and rarely identified as a serious illness by the care provider. A recent history of treatment with antimalarials and iron was rare. Compliance with vaccinations delivered through the Expanded Programme of Immunization (EPI) was 82% and was notassociated with risk of anaemia. Anaemia is extremely common in south-eastern United Republic of Tanzania, even in very young infants. Further implementation of the Integrated Management of Childhood Illness algorithm should improve the case management of anaemia. However, the asymptomatic nature of most episodes of anaemia highlights the need for preventive strategies. The EPI has good coverage of the target population and it may be an appropriate channel for delivering tools for controlling anaemia and malaria.