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Michiko Masutani - One of the best experts on this subject based on the ideXlab platform.

  • The Global Response to tropical heating in the Madden–Julian oscillation during the northern winter
    Quarterly Journal of the Royal Meteorological Society, 2004
    Co-Authors: Adrian J. Matthews, Brian J. Hoskins, Michiko Masutani
    Abstract:

    A life cycle of the Madden–Julian oscillation (MJO) was constructed, based on 21 years of outgoing long-wave radiation data. Regression maps of NCEP–NCAR reanalysis data for the northern winter show statistically significant upper-tropospheric equatorial wave patterns linked to the tropical convection anomalies, and extratropical wave patterns over the North Pacific, North America, the Atlantic, the Southern Ocean and South America. To assess the cause of the circulation anomalies, a Global primitive-equation model was initialized with the observed three-dimensional (3D) winter climatological mean flow and forced with a time-dependent heat source derived from the observed MJO anomalies. A model MJO cycle was constructed from the Global Response to the heating, and both the tropical and extratropical circulation anomalies generally matched the observations well. The equatorial wave patterns are established in a few days, while it takes approximately two weeks for the extratropical patterns to appear. The model Response is robust and insensitive to realistic changes in damping and basic state. The model tropical anomalies are consistent with a forced equatorial Rossby–Kelvin wave Response to the tropical MJO heating, although it is shifted westward by approximately 20° longitude relative to observations. This may be due to a lack of damping processes (cumulus friction) in the regions of convective heating. Once this shift is accounted for, the extratropical Response is consistent with theories of Rossby wave forcing and dispersion on the climatological flow, and the pattern correlation between the observed and modelled extratropical flow is up to 0.85. The observed tropical and extratropical wave patterns account for a significant fraction of the intraseasonal circulation variance, and this reproducibility as a Response to tropical MJO convection has implications for Global medium-range weather prediction. Copyright © 2004 Royal Meteorological Society

  • The Global Response to tropical heating in the Madden–Julian oscillation during the northern winter
    Quarterly Journal of the Royal Meteorological Society, 2004
    Co-Authors: Adrian J. Matthews, Brian J. Hoskins, Michiko Masutani
    Abstract:

    A life cycle of the Madden-Julian Oscillation (MJO) was constructed, based on 21 years of outgoing longwave radiation data. Regression maps of NCEP-NCAR reanalysis data for northern winter show statistically significant upper-tropospheric equatorial wave patterns linked to the tropical convection anomalies, and extratropical wave patterns over the North Pacific, North America, the Atlantic, the Southern Ocean and South America. To assess the cause of the circulation anomalies, a Global primitive equation model was initialised with the observed three-dimensional winter climatological-mean flow and forced with a time-dependent heat source derived from the observed MJO anomalies. A model MJO cycle was constructed from the Global Response to the heating, and both the tropical and extratropical circulation anomalies generally matched the observations well. The equatorial wave patterns are established in a few days, while it takes approximately two weeks for the extratropical patterns to appear. The model Response is robust and insensitive to realistic changes in damping and basic state. The model tropical anomalies are consistent with a forced equatorial Rossby--Kelvin wave Response to the tropical MJO heating, although it is shifted westward by approximately 20 longitude relative to observations. This may be due to a lack of damping processes (cumulus friction) in the regions of convective heating. Once this shift is accounted for, the extratropical Response is consistent with theories of Rossby wave forcing and dispersion on the climatological flow, and the pattern correlation between the observed and modelled extratropical flow is up to 0.85. The observed tropical and extratropical wave patterns accounts for a significant fraction of the intraseasonal circulation variance, and this reproducibility as a Response to tropical MJO convection has implications for Global medium-range weather prediction

Jane Parry - One of the best experts on this subject based on the ideXlab platform.

  • At last a Global Response to viral hepatitis.
    Bulletin of the World Health Organization, 2010
    Co-Authors: Jane Parry
    Abstract:

    Viral hepatitis affects approximately 500 million people around the world - more than 10 times the number affected by HIV/AIDS. Different viruses can cause various forms of viral hepatitis. While type A viral hepatitis is an acute and transient illness with low mortality, hepatitis B and C infections can become chronic and lead to liver cirrhosis and cancer. Hepatitis A is spread through contact with infected people or contaminated food or water--but hepatitis B and C are mainly acquired through contaminated needles or infected blood products. Infection patterns are diffuse. Most people with some form of chronic viral hepatitis, which can remain latent for decades, don't know how they became infected. All population groups are affected by viral hepatitis, but the poor are often the worst hit. Stigma and misinformation are rife. Treatment is expensive. In some countries, such as China, people who are chronically infected face discrimination. An estimated 350 million people are chronically infected with hepatitis B--with Asia shouldering a disproportionately high burden--and 170 million with hepatitis C. The epidemic wreaks a trail of destruction wherever unsafe health care, injection and blood handling practices are common. Dr Steven Wiersma, medical officer and hepatitis focal point at the World Health Organization (WHO) in Geneva, says "the burden of disease is truly dramatic, yet viral hepatitis has been forgotten [and] misplaced: That is set to change now, since countries called for Global concerted action to tackle the problem in a resolution passed in May 2010 at the 63rd World Health Assembly (WHA). "It was the strenuous efforts of patients' advocacy groups that ... put [it] on [the] WHA agenda:' Wiersma says. Countries recognized WHO's "good work, for example in helping them with viral hepatitis prevention through immunization, and blood and injection safety education", he says. The WHA resolution, passed unanimously, was a starting point for a Global coordinated Response, covering vaccination, testing and treatment for patients, education and advocacy for those living with the disease, and research and support to help countries formulate their own national Responses. [ILLUSTRATION OMITTED] More needs to be done to treat the millions of people living with chronic hepatitis and to prevent people dying from resulting liver cancer and liver cirrhosis, says Charles Gore, president of the World Hepatitis Alliance. More should be done to educate health-care workers about blood and needle safety and to fight the stigma and ignorance, Gore says. According to WHO estimates, every year there are 21 million cases of hepatitis B caused by unsafe injections in health-care settings. "There is not a country in the world where viral hepatitis isn't a problem" he says. "HIV and malaria are only in certain countries, hepatitis is everywhere. In terms of infectious disease, you could say this is the biggest challenge we have, particularly given how little is in place to deal with it." The Viral Hepatitis Global Policy Survey was developed by the World Hepatitis Alliance in partnership with WHO after Member States were asked what they needed to step up their fight against viral hepatitis. The survey revealed deep concern: 80% of the 135 countries said viral hepatitis was an urgent public health issue but complained they had no money for it. One third of countries had no prevalence data at all. Countries said more than half of their populations had no access to free testing while very few governments ran public awareness campaigns about hepatitis. "We found that vaccination comes quite low down the list. All respondents wanted help with surveillance, goal setting and awareness. Once we started talking about it we were amazed that people recognized the need to do something" says Gore. For hepatitis C, there is no vaccine and the disease, often associated with injecting drug use, is found in diverse countries. …

Leona D Samson - One of the best experts on this subject based on the ideXlab platform.

  • Global Response of saccharomyces cerevisiae to an alkylating agent
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Scott A. Jelinsky, Leona D Samson
    Abstract:

    DNA chip technology enables simultaneous examination of how ≈6,200 Saccharomyces cerevisiae gene transcript levels, representing the entire genome, respond to environmental change. By using chips bearing oligonucleotide arrays, we show that, after exposure to the alkylating agent methyl methanesulfonate, ≈325 gene transcript levels are increased and ≈76 are decreased. Of the 21 genes that already were known to be induced by a DNA-damaging agent, 18 can be scored as inducible in this data set, and surprisingly, most of the newly identified inducible genes are induced even more strongly than these 18. We examined 42 responsive and 8 nonresponsive ORFs by conventional Northern blotting, and 48 of these 50 ORFs responded as they did by DNA chip analysis, with magnitudes displaying a correlation coefficient of 0.79. Responsive genes fall into several expected and many unexpected categories. Evidence for the induction of a program to eliminate and replace alkylated proteins is presented.

  • Global Response of Saccharomyces cerevisiae to an alkylating agent
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Scott A. Jelinsky, Leona D Samson
    Abstract:

    DNA chip technology enables simultaneous examination of how approximately 6,200 Saccharomyces cerevisiae gene transcript levels, representing the entire genome, respond to environmental change. By using chips bearing oligonucleotide arrays, we show that, after exposure to the alkylating agent methyl methanesulfonate, approximately 325 gene transcript levels are increased and approximately 76 are decreased. Of the 21 genes that already were known to be induced by a DNA-damaging agent, 18 can be scored as inducible in this data set, and surprisingly, most of the newly identified inducible genes are induced even more strongly than these 18. We examined 42 responsive and 8 nonresponsive ORFs by conventional Northern blotting, and 48 of these 50 ORFs responded as they did by DNA chip analysis, with magnitudes displaying a correlation coefficient of 0.79. Responsive genes fall into several expected and many unexpected categories. Evidence for the induction of a program to eliminate and replace alkylated proteins is presented.

Isabelle Giraudon - One of the best experts on this subject based on the ideXlab platform.

  • Roundtable discussion: how lessons learned from HIV can inform the Global Response to viral hepatitis
    BMC Infectious Diseases, 2014
    Co-Authors: Jeffrey V. Lazarus, Jordi Casabona, Lucas Wiessing, Maria Kantzanou, Mirjam Kretzschmar, Catharina Matheï, Peter Vickerman, Jens D. Lundgren, Maria Prins, Isabelle Giraudon
    Abstract:

    IntroductionBy Jeffrey V Lazarus.In the last few years, as viral hepatitis has become amore prominent issue on national and internationalhealth agendas, talk of“learning from HIV” has becomequite common. It is understandable for researchers, pol-icy-makers and activists to make this link, given the nota-ble commonalities between HIV, hepatitis B and hepatitisC. All are life-threatening blood-borne viruses that affecthundreds of millions of people worldwide. All can remainasymptomatic for many years, making it difficult to pro-mote awareness of their danger. Ignorance about all ofthe major forms of viral hepatitis, particularly B and C,understandably reminds many people who are workingto confront this issue of the early years of the AIDS epi-demic, when a combination of misinformation andunwillingness to candidly address stigmatised behavioursand social inequalities led to a widespread failure to for-mulate a cohesive public health Response.Other parallels might be elucidated, and there is cer-tainly good reason to think of the Global HIV, hepatitisB and hepatitis C epidemics as having similar trajectoriesin some regards. Nonetheless, the differences betweenHIV and viral hepatitis– in terms of how these varieddiseases manifest both biologically and socially– shouldmake us wary of oversimplifying the connection.As discussions about hepatitis policies and strategiesgain momentum at the national and Global level, it isbecoming increasingly important to articulate the“lessons learned” from the HIV field. Pertinent issuesinclude disease preventionmeasures, testing and earlydiagnosis, the scale-up of treatment, and barriers to ser-vice uptake and retention in care. Key social and politicalfactors associated with viral hepatitis call to mind otherpossible lessons relating to the value of civil societyengagement, leadership and governance issues, resourcemobilization including innovative financing, the causesand consequences of stigma, and the role of socialscience in addressing health threats.This is clearly a rich and important realm of inquiry–and it is time to move beyond the general calls to learnfrom HIV and begin to systematically formulate specificlessons. As a preliminary step, the following roundtablepresents the insights of a range of experts who were invitedto reflect on how experiences from the Global Response toHIV might inform the Global Response to viral hepatitis.Kicking off the discussion is Jens Lundgren, a renownedHIV researcher, head of the new WHO CollaboratingCentre on HIV and Viral Hepatitis and co-founder of theHIV in Europe Initiative. His perspective is much broaderthan that of a medical doctor gazing at his own disease. Inthe next two pieces, Jordi Casabona of the EpidemiologicalCenter for HIV/AIDS/STI of Catalonia and Lucas Wies-sing of the European Monitoring Centre for Drugs andDrug Addiction (and colleagues) consider surveillance andmonitoring issues. Sounding a cautionary note about the“discourse of hope and expectation” associated with hepa-titis C treatment, Magdalena Harris, a qualitativeresearcher at the London School of Hygiene and TropicalMedicine, critically reflects on treatment as prevention.

Adrian J. Matthews - One of the best experts on this subject based on the ideXlab platform.

  • The Global Response to tropical heating in the Madden–Julian oscillation during the northern winter
    Quarterly Journal of the Royal Meteorological Society, 2004
    Co-Authors: Adrian J. Matthews, Brian J. Hoskins, Michiko Masutani
    Abstract:

    A life cycle of the Madden–Julian oscillation (MJO) was constructed, based on 21 years of outgoing long-wave radiation data. Regression maps of NCEP–NCAR reanalysis data for the northern winter show statistically significant upper-tropospheric equatorial wave patterns linked to the tropical convection anomalies, and extratropical wave patterns over the North Pacific, North America, the Atlantic, the Southern Ocean and South America. To assess the cause of the circulation anomalies, a Global primitive-equation model was initialized with the observed three-dimensional (3D) winter climatological mean flow and forced with a time-dependent heat source derived from the observed MJO anomalies. A model MJO cycle was constructed from the Global Response to the heating, and both the tropical and extratropical circulation anomalies generally matched the observations well. The equatorial wave patterns are established in a few days, while it takes approximately two weeks for the extratropical patterns to appear. The model Response is robust and insensitive to realistic changes in damping and basic state. The model tropical anomalies are consistent with a forced equatorial Rossby–Kelvin wave Response to the tropical MJO heating, although it is shifted westward by approximately 20° longitude relative to observations. This may be due to a lack of damping processes (cumulus friction) in the regions of convective heating. Once this shift is accounted for, the extratropical Response is consistent with theories of Rossby wave forcing and dispersion on the climatological flow, and the pattern correlation between the observed and modelled extratropical flow is up to 0.85. The observed tropical and extratropical wave patterns account for a significant fraction of the intraseasonal circulation variance, and this reproducibility as a Response to tropical MJO convection has implications for Global medium-range weather prediction. Copyright © 2004 Royal Meteorological Society

  • The Global Response to tropical heating in the Madden–Julian oscillation during the northern winter
    Quarterly Journal of the Royal Meteorological Society, 2004
    Co-Authors: Adrian J. Matthews, Brian J. Hoskins, Michiko Masutani
    Abstract:

    A life cycle of the Madden-Julian Oscillation (MJO) was constructed, based on 21 years of outgoing longwave radiation data. Regression maps of NCEP-NCAR reanalysis data for northern winter show statistically significant upper-tropospheric equatorial wave patterns linked to the tropical convection anomalies, and extratropical wave patterns over the North Pacific, North America, the Atlantic, the Southern Ocean and South America. To assess the cause of the circulation anomalies, a Global primitive equation model was initialised with the observed three-dimensional winter climatological-mean flow and forced with a time-dependent heat source derived from the observed MJO anomalies. A model MJO cycle was constructed from the Global Response to the heating, and both the tropical and extratropical circulation anomalies generally matched the observations well. The equatorial wave patterns are established in a few days, while it takes approximately two weeks for the extratropical patterns to appear. The model Response is robust and insensitive to realistic changes in damping and basic state. The model tropical anomalies are consistent with a forced equatorial Rossby--Kelvin wave Response to the tropical MJO heating, although it is shifted westward by approximately 20 longitude relative to observations. This may be due to a lack of damping processes (cumulus friction) in the regions of convective heating. Once this shift is accounted for, the extratropical Response is consistent with theories of Rossby wave forcing and dispersion on the climatological flow, and the pattern correlation between the observed and modelled extratropical flow is up to 0.85. The observed tropical and extratropical wave patterns accounts for a significant fraction of the intraseasonal circulation variance, and this reproducibility as a Response to tropical MJO convection has implications for Global medium-range weather prediction