Ny kunskap f - PowerPoint PPT Presentation

1 / 44
About This Presentation
Title:

Ny kunskap f

Description:

Smittsamma sjukdomars inverkan p det svenska samh llet: mot ... Intervenable mechanisms mediating pandemic spread. Individual person. Prevention knowledge ... – PowerPoint PPT presentation

Number of Views:58
Avg rating:3.0/5.0
Slides: 45
Provided by: HenrikE
Category:

less

Transcript and Presenter's Notes

Title: Ny kunskap f


1
PROSPER Smittsamma sjukdomars inverkan på
det svenska samhället mot evidensbaserade
responsstrategier
  • Toomas Timpka Henrik Eriksson Elin A
    Gursky
  • Anders Grimvall Joakim Ekberg Olle
    Eriksson
  • Magnus Strömgren Einar Holm Lars
    Valter
  • James M Nyce

2
The CriSim group
  • Department of Computer and Information Science
  • Department of Medicine and Health Sciences
  • Linköping University, Linköping, Sweden
  • ANSER/Analytic Services Inc.
  • Arlington, VA., USA
  • Department of Social and Economic Geography
  • Umeå University, Umeå, Sweden
  • Department of Anthropology
  • Ball State University, Muncie, IN., USA

3
Introduction
  • Over the last decades, several serious infectious
    diseases have emerged rapidly to become global
    threats, including the severe acute respiratory
    syndrome (SARS) and avian influenza.
  • Each of these diseases has required a fast and
    specific response from policy-makers and public
    health authorities.
  • Such a situation occurred in 2009 with the
    emergence of the of a novel A/H1N1 influenza
    virus (the swine flu) in Mexico.

4
Introduction the swine flu
  • On 28 April, Mexico had 26 confirmed human cases
    with seven confirmed deaths. Elsewhere, there
    were confirmed cases and deaths in the USA,
    Canada, UK, Spain, New Zealand, and Israel (1).
  • On 11 May, researchers analyzing data from the
    Mexican outbreak reported that the
    transmissibility of the new influenza strain was
    substantially higher than for seasonal flu, and
    comparable with lower estimates of the basic
    reproduction rate obtained from previous
    influenza pandemics (2).
  • One month later, transmission in several
    countries could no longer be traced to
    clearly-defined chains of human-to-human
    contacts, and further spread was considered
    inevitable. Accordingly, with 30.000 confirmed
    cases in 74 counties, the WHO raised the
    influenza pandemic alert to the highest level,
    phase 6 (WHO 2009)
  • 1. Swine influenza how much of a global threat?
    Lancet 2009373(9674)1495.
  • 2. Fraser C, Donnelly CA, Cauchemez S, et al.
    Pandemic Potential of a Strain of Influenza A
    (H1N1) Early Findings. Science 2009. DOI
    10.1126/science.1176062

5
Pandemic influenza
  • Global epidemic with high mortality
  • Spanish influenza (1918)
  • Asian flu (1957)
  • Hongkong flu (1968)
  • Modified (1918) or reassorted (1957, 1968) avian
    virus
  • Destructive in non-traditional risk groups
  • Taubenberger et al, Nature 2005437889-892.

Edward Munch After the Spanishdisease (self
portrait), 1919.
6
Introduction public health response
  • Public health officials in nations affected
    by the swine flu decided on response actions
  • In the absence of a vaccine, closure of schools
    with infected pupils was used by some countries,
    but not others
  • In the USA, the CDC initially supported school
    closures
  • The Public Health Agency of Canada did not
    recommend closing schools
  • The UK Health Protection Agency took the position
    that consideration should be given to
    temporarily closing the school (1)
  • 1. Editorial. Putting influenza A H1N1 in its
    place. Lancet Infectious Diseases.
    2009DOI10.1016/S1473-3099(09)70134-3 1.

7
Introduction infrastructural issues
  • The principles for forming the response to the
    swine flu seem to have remained
    unsystematically linked to the particular forms
    of disease validation and prediction locally on
    hand.
  • If poorly validated and coordinated methods are
    allowed to inform policy-making on emerging
    infectious diseases, these methods may
    dangerously mislead critical response
    implementation (1,2)
  • The social distancing example from the swine
    flu outbreak is particularly disquieting in
    light of that the effectiveness of this set of
    measures recently had been questioned because of
    the major impediments to compliance (3).
  • 1. ECDC. Now-casting and short-term forecasting
    during influenza pandemics - a focused
    developmental ECDC workshop. Stockholm ECDC,
    2007.
  • 2. Timpka T, Eriksson H, Gursky E, et al.
    Population-based simulations of influenza
    pandemics validity and significance for public
    health policy. Bull World Health Organ
    200987305-311.
  • 3. Rothstein MA, Talbott MK. Encouraging
    compliance with quarantine a proposal to provide
    job security and income replacement. Am J Public
    Health 200797 Suppl 1S49-56.

8
Overview of workflow in establishment of evidence
on rapidly emerging infectious disease outbreaks
9
Research problems
  • There is no common infrastructure in place for
    analyses of pandemic data and sharing of
    information
  • The co-ordination of the response within nations
    and across national borders remains an issue
  • An information infrastructure is required
    that differs from traditional health information
    systems in that it is to be used in situations
    when infectious diseases overwhelm the
    first-order resources on hand designed to detect
    and control the outbreak.

10
Research aims
  • to draft a protocol that can be used to realize a
    standardized information infrastructure for rapid
    production of pandemic response program evidence
  • The hypothesis is that it is possible to
    standardize the establishment of a distributed
    global infrastructure for rapidly translating
    evidence from analyses of available data into
    coordinated response when addressing worldwide
    emerging infectious diseases.

11
Methods
  • Overview of the methods used for
  • A. Data collection
  • B. Data analysis

12
Methods
  • Data collection
  • A nominal group method (1) was used to collect
    requirements data.
  • Two expert panels examined and outlined
    requirements on the protocol with regard to the
    scope of data sources and analytic functions to
    be covered, respectively.
  • Individual experts reviewed a working
    requirements document followed by telephone
    discussions (n18).
  • Requirements on the data were defined by a panel
    consisting of scientists and practitioners (n8)
    with backgrounds in medicine, epidemiology,
    medical anthropology, computer science, health
    informatics, cognitive science, and
    socio-economic geography.
  • The panel examining requirements on analytic
    functions consisted of scientists and
    practitioners (n5) with backgrounds in medicine,
    statistics, computer science, health informatics,
    and cognitive science.
  • When subsequent turns did not return significant
    changes in the documents, the requirement
    specifications were considered to be established.
  • 1, Jones J, Hunter D. Consensus methods for
    medical and health services research. Bmj
    1995311(7001)376-80.

13
Methods
  • Data analysis
  • A method for rational solution of multi-facetted
    design problems (1,2) was used for data analysis
  • The members of the two panels were merged into
    one protocol specification group
  • The task communicated to the group was to
    formulate a protocol design using the
    requirements, their subject matter expertise, and
    the published literature. The experts first
    provided their individual comments, which were
    collected by a design process coordinator
  • Formulation of functional design solutions was
    performed independently by experts who reviewed a
    document describing the model described as design
    patterns
  • The design patterns were represented in the form
    Title, Problem-Requirements, Functional design,
    and Realization
  • In the final step, the design patterns were
    summarized in the PROSPER protocol (PROtocol for
    Standardized Pandemic and Emerging infectious
    disease Response)
  • 1. Rittel H, Webber M. Dilemmas in a general
    theory of planning. Policy Sciences
    19734(2)55-169.
  • 2. Simon H. Design of the artificial. 2nd ed.
    Cambridge, Mass. The MIT Press, 1981.

14
Results - requirements
  • Status overview Major problems during the early
    stages of pandemic planning include
  • - analytic methods and technologies are
    uncoordinated with the organization of response
    programs
  • - shortage of reliable microbiological and
    epidemiological data, and
  • - lack of universally applicable detection
    and forecasting methods
  • Data requirements Specifications are needed of
    population and community data, the quality and
    timeliness of outbreak data, and on how data on
    population behavior are represented, especially
    over time
  • Analytic functions requirements Comparative
    assessments of response program effectiveness,
    rather than efficacy, are needed

15
Results PROSPER
  • The PROSPER protocol outlines an information
    infrastructure for pandemic response that is
    defined with reference to response program
    implementation.
  • The infrastructure can be realized using
    conventional system implementation methods by
    regional, national and international public
    health agencies or other organizations with an
    interest in rapidly responding to pandemic
    threats.
  • PROtocol for Standardized Pandemic and Emerging
    infectious disease Response

16
Results
  • Display of the PROSPER protocol in relation to
    intervention program implementation (1)
  • 1. Rogers E. Diffusion of Innovations. Fifth ed.
    New York Free Press, 2003.

17
Results
  • The PROSPER infrastructure covers analyses of the
    response context, the response processes, and
    outcomes and impacts. For each of these aspects,
    it outlines the basic infrastructure at levels of
    evidence, function, and technical systems.
  • Evidence on the program context is organized with
    reference to the STROBE, guidelines on what
    should be included in reports of observational
    studies
  • Reports on the process design and program
    effectiveness are organized according to the
    SQUIRE guidelines for reporting studies of
    quality improvement in health services

18
(No Transcript)
19
Results
  • The structure of the functional level reflects
    the methods used to produce pandemic evidence and
    the organization of infectious disease response.
  • The Capacity and needs assessment function is
    informed at the technical systems level be
    systems for laboratory and syndromic data access
    and visualization, and analysis scenario
    management (Table 1).

20
(No Transcript)
21
Results
  • Table 1. PROSPER design pattern Capacity and
    needs assessment.
  • Capacity and needs assessment
  • Analysis scenario management
  • Problem-Requirements A1 Sociogeographical
    representation of communities
  • Functional design A spatially explicit model for
    population representation is used to allow for
    experiments in full scale with factual and
    synthetic populations. This design solution
    supports that different sociogeographical
    scenarios can be defined by changing the starting
    conditions of the model. Other basic model
    categories included in the pandemic outbreak
    scenario define transportation systems and other
    geographic conditions, e.g. location of
    workplaces, schools, and facilities for sports
    and entertainment events. The representations
    also include relational variables, such as
    individual-mother, -partner, -child, and
    co-worker at workplace. These relational
    variables are directly relevant for
    representation of the social networks
    transmitting infectious agents. In other words,
    sociogeographical preprocessing of spatially
    explicit population data are used to in advance
    identify specific groups and populations that may
    require more careful and intensified
    surveillance. The Strengthening the Reporting of
    Observational Studies in Epidemiology (STROBE)
    recommendations (1) on what should be included in
    accurate reports of observational studies are
    used to organize the communication of evidence
    from the analyses.
  • Realization The scenario management is based on
    the ontology handling system Protégé (2). In
    addition to the SVERIGE (System for Visualizing
    Economic and Regional Influences Governing the
    Environment) model for sociogeographical
    representation of the Swedish population (3),
    preliminary settings for additional scenario
    models have been developed, representing, e.g.
    local social interaction and commuting patterns
    (4).
  • Access to epidemiological and population data
  • Problem-Requirements A2 Control and
    visualization of data quality and timeliness
  • Design solution Epidemiological data from factual
    outbreaks are complemented with artificially
    generated data and collected into databases for
    use in detailed analyses of historical outbreaks
    and experiments on hypothetical outbreaks in
    populations. The factual outbreak data range
    from highly specific genomic and microbiological
    laboratory data to non-specific syndromic data,
    e.g. from telephone health advice centers and
    Internet website logs (5, 6). All data sources
    are controlled by methods for systematic
    statistical follow-up of the data used. In
    particular short-term trends in the pandemic
    progress can easily be masked by errors in
    sampling or laboratory practices. Statistical
    tools for trend analysis, such as semiparametric
    regression models (7), are therefore used to
    identify causes to flaws in the data collection
    routines that can lead to erroneous
    interpretations.
  • Realization Population-based administrative
    healthcare databases (8) are used to assemble
    geographically explicit data from infections
    disease outbreaks at local levels. In Sweden, the
    regional telephone health advice services have
    been synchronized into a national call center
    supported by a telehealth Electronic Patient
    Record (EPR), where the reason for contact and
    residence for each caller is documented using a
    controlled terminology. We use the national
    database collecting data from all regional
    telehealth EPRs as a source for syndromic
    surveillance data. Regarding visualization
    services, these have not been included in the
    present realization. Instead, interactive graphs
    (www.ggobi.org) and motion chart
    (www.gapminder.org) services available at the
    Internet are used for getting overviews of large
    data sets.
  • References
  • 1. von Elm E, Altman DG, Egger M, Pocock SJ,
    Gøtzsche PC, Vandenbroucke JP STROBE Initiative.
    The Strengthening the Reporting of Observational
    Studies in Epidemiology (STROBE) statement
    guidelines for reporting observational studies. J
    Clin Epidemiol. 2008 Apr61(4)344-9.
  • 2. Gennari JH, Musen MA, Fergerson RW, Grosso WE,
    Crubézy M, Eriksson H, et al. The evolution of
    Protégé An environment for knowledge-based
    systems development. Int J Hum Comp Stud
    200358(1)89-123.
  • 3. Holm E, Holme K, Mäkilä K, Mattsson-Kauppi M,
    Mörtvik G. The SVERIGE Spatial Microsimulation
    Model Content, Validation, and Example
    Applications. GERUM 20024.
  • 4. Holm E, Timpka T. A discrete time-space
    geography for epidemiology from mixing groups to
    pockets of local order in pandemic simulations.
    Stud Health Technol Inform 2007129464-8.
  • 5. Sintchenko V, Gallego B. Laboratory-guided
    detection of disease outbreaksthree generations
    of surveillance systems. Arch Pathol Lab Med.
    2009 Jun133(6)916-25.
  • 6. Smith GJ, Vijaykrishna D, Bahl J, Lycett SJ,
    Worobey M, Pybus OG, Ma SK, Cheung CL, Raghwani
    J, Bhatt S, Peiris JS, Guan Y, Rambaut A. Origins
    and evolutionary genomics of the 2009
    swine-origin H1N1 influenza A epidemic. Nature.
    2009 Jun 11. Epub ahead of print PubMed PMID
    19516283.
  • 6. Wahlin K, Grimvall A. Uncertainty in water
    quality data and its implications for trend
    detection lessons from Swedish environmental
    data. Environmental Science and Policy
    200811115-124.
  • 7. Wirehn AB, Karlsson HM, Carstensen JM.
    Estimating disease prevalence using a
    population-based administrative healthcare
    database. Scand J Public Health 200735(4)424-31.

22
Results
  • The functions for Implementation process
    evaluation are supported by technical systems for
    response process analysis and knowledge-base
    maintenance (Table 2).

23
(No Transcript)
24
Results
  • Table 2. PROSPER design pattern Implementation
    process evaluation (section)
  • Implementation process evaluation
  • Iterative response program implementation
  • Problem-Requirements A3 Explicit representation
    of populations over time, D1 Adjustments to
    missing data, I2 Explicit fact and hypothesis
    management
  • Functional design An iterative procedure for
    response program design was envisioned, where
    analyses of virtual outbreak detection and
    simulated interventions are used until real-time
    surveillance data and evaluations of factual
    interventions become available. The disease
    models used in the virtual analyses are
    preliminarily instantiated from the literature,
    e.g. with regard to incubation period and serial
    interval. Thereafter, program components are
    specified in intervention models. Response
    program developers can prepare process analyses
    by configuring program components and specifying
    intervention model parameters, e.g. the
    prophylactic performance of specific antiviral
    drugs or combinations. The SQUIRE guidelines for
    reporting studies of quality improvement in
    health services (1) are used for communication of
    evidence from the analyses.
  • Realization The engineering principle underlying
    the example system is separation between the
    software for management of the outbreak models
    and the software for execution of the analyses
    (2). This separation allows flexible modeling to
    represent unexpected events and circumstances,
    while maintaining the run-time performance of
    outbreak detection and simulation programs. Basic
    disease and intervention characteristics are
    available from profiles reported in the
    literature (3) and at the Internet
    (https//www.epimodels.org/midas/modelProfilesFull
    .do). The basic models are combined and for a
    typology of explicit models and baseline
    parameter settings.
  • References
  • 1. Davidoff F, Batalden P, Stevens D, Ogrinc G,
    Mooney S SQUIRE development group. Publication
    guidelines for quality improvement in health
    care evolution of the SQUIRE project. Qual Saf
    Health Care. 2008 Oct17 Suppl 1i3-9.
  • 2. Eriksson H, Morin M, Jenvald J, Gursky E, Holm
    E, Timpka T. Ontology based modeling of pandemic
    simulation scenarios. Stud Health Technol Inform
    2007129755-9.
  • 3. Carrat F, Vergu E, Ferguson NM, Lemaitre M,
    Cauchemez S, Leach S, et al. Time lines of
    infection and disease in human influenza a
    review of volunteer challenge studies. Am J
    Epidemiol 2008167(7)775-85.

25
Results
  • The last section of the protocol, Outcome and
    impact evaluation outlines the details for the
    comparative analyses of outbreak algorithms and
    the assessment of intervention effectiveness
    (Table 3).

26
(No Transcript)
27
Results
  • The functions for comparative analyses in the
    outcome and impact evaluation section are based
    on technical systems for simulations and
    statistical analyses that can be acquired without
    major financial investments, by utilizing
    knowledge based systems techniques and networked
    cloud computing

28
PROSPER examples A two-tier model of epidemic
progression the biological tier
Incubation 1-3 days (average 1.9 days)
Contagious 3-6 days (average 4.1 days)
29
PROSPER examples A two-tier model of epidemic
progression the sociogeographical tier
  • Geographical
  • Logistical
  • Social
  • Cultural
  • Mixing network approach to represent meeting
    places as social pockets
  • Households are central social pockets

30
Day rest with symptoms Decision
modifiers Personal care resources Healthcare
access Health beliefs
Symptoms development
Non-intervenable conditions modifying pandemic
spread Individual person Sex Age Genetic
constitution Ethnicity Formal education Employment
Physical environment Climate Urbanisation
level Transportation network Social
environment Community Market and economy Social
capital Family Financial resources Family
structure and roles Social network
Intervenable mechanisms mediating pandemic spread
Individual person Prevention knowledge Compliance
to policies Self-protective behaviour Immunizatio
n Nutritional status Physical environment Healthc
are facilities Schools Workplaces Sanitary
standard Information infrastructure Social
environment Community Laws and regulations
Pandemic plans Mass media Family Family
behaviour
Individual person Regular social interaction in
personal social pockets in the
community Exposure to infectious individuals
Not infected
Asymptomatic infection
  • Day rest
  • Decision modifiers
  • Health beliefs
  • Mental models
  • of pandemic
  • of society

Social geographic data and assumptions regarding
social order
31
PROSPER examples Management of two-tier
simulation models - the PROTEGÉ ontology
handling system
32
PROSPER examples Cloud computing for outsourcing
of complex computations
  • Simulations are defined in the ontology
    management system and thereafter distributed to
    anetworked computing environment

33
We set out to compute a preliminary Neighborhood
Influenza Susceptibility Index (NISI) describing
the vulnerability of local communities of
different geo-socio-physical structure to a
pandemic influenza outbreak.
  • Responding to the current pandemic and preparing
    for future ones requires critical planning for
    the early phases where there is no availability
    of pandemic vaccine.

34
The Neighborhood Influenza Susceptibility Index
(NISI)
  • The aim was to pre-compute maps describing local
    variations between geographical areas with regard
    to susceptibility to influenza transmission.
  • The maps can be employed by local public health
    officials for planning of response measures
    before factual transmission data are at hand.
  • Specifically, computation of a preliminary
    Neighborhood Influenza Susceptibility Index
    (NISI) is used to describe the vulnerability of
    local communities of different geo-socio-physical
    structure to a pandemic influenza outbreak.
  • In difference to seasonal influenza, the herd
    immunity to a pandemic is by definition low,
    leading to that disease transmission largely is
    determined by the pattern of social contacts in
    the community.
  • The NISI is estimated from a standardized virtual
    outbreak. One person per 1000 individuals in the
    fully susceptible study community is randomly
    selected and infected at t0, defined to be 9am
    the first day of the simulation.
  • The rates of secondary infected individuals in
    different neighborhoods and the sociodemographic
    characteristics of these cases are thereafter
    recorded during the progress of the outbreak.
  • Neither behavioral changes nor any further
    introduction of infected individuals by commuting
    and national or international travel are expected
    to take place during the standardized virtual
    outbreak.
  • The preliminary NISI is finally computed as the
    proportion of infected at the end of the virtual
    outbreak.

35
  • Geographical distribution of neighborhoods in the
    study municipality

36
  • Epidemic curves for the virtual outbreaks (n10)
    generated for Linköping municipality

37
  • Epidemic curves for the standardized outbreak
    displayed by neighborhood (n13).

38
  • Numbers of uninfected individuals at selected
    days of the virtual outbreak displayed by
    neighborhood

39
  • Aggregate-level neighborhood socioeconomic data
    in percent displayed by descending NISI/H1N1 t120
    (proportion of infected individuals) at the end
    of the virtual outbreak.

40
Discussion
  • We have drafted the PROSPER protocol that can be
    used to realize a standardized information
    infrastructure for rapid production of pandemic
    response program evidence in different
    organizational and technical settings.
  • The protocol is optimized with regard to analyses
    of response program effectiveness in particular
    communities and populations worldwide.
  • In areas such as urban planning, pattern
    languages have been extensively used to transfer
    value-bearing design features between different
    milieus (1)
  • 1. Alexander C. The timeless way of building.
    Oxford Oxford University Press, 1979.

41
Discussion
  • It is necessary to caution against
    over-interpretation of predictive modeling
    results in policy-making settings, even in
    situations where different models display similar
    effectiveness of interventions (1).
  • Analyses based on explorative modeling tools of
    what-if analysis type, such as FluAid and
    FluSurge/ have previously been used to directly
    inform policy recommendations concerning hospital
    surge capacity (2) and loss of medical work time
    (3) when planning pandemic responses.
  • These modeling environments are not adjusted to
    the requirement that health intervention programs
    must be evidence-based.
  • The PROSPER protocol is specifically adapted to
    that without being able to inspect, understand
    and adjust baseline assumptions, it is not clear
    to what extent policy makers will use, let alone
    trust and rely on, the analytic resources
    included in the infrastructure.
  • 1. Halloran ME, Ferguson NM, Eubank S, Longini
    IM, Jr., Cummings DA, Lewis B, et al. Modeling
    targeted layered containment of an influenza
    pandemic in the United States. Proc Natl Acad Sci
    U S A 2008.
  • 2. Ten Eyck RP. Ability of regional hospitals to
    meet projected avian flu pandemic surge capacity
    requirements. Prehosp Disaster Med
    200823(2)103-12.
  • 3. Wilson N, Baker M, Crampton P, Mansoor O. The
    potential impact of the next influenza pandemic
    on a national primary care medical workforce. Hum
    Resour Health 200537.

42
Discussion limitations
  • As for the technical systems level of PROSPER,
    some items identified in the requirements
    analysis were not covered by the present version
    of PROSPER.
  • A technology that can support reliable,
    short-term forecasts is nowcasting, i.e.
    short-term predictions that rely on
    straight-forward extrapolation of recent
    observations in time (1).
  • Early identification of the virus genome is
    central in the response to pandemic influenza
    (2). The laboratory system infrastructure is not
    in detail included in the present version of
    PROSPER.
  • 1. Wilson N, Baker M, Crampton P, Mansoor O. The
    potential impact of the next influenza pandemic
    on a national primary care medical workforce. Hum
    Resour Health 200537.
  • 2. Sintchenko V, Gallego B. Laboratory-guided
    detection of disease outbreaksthree generations
    of surveillance systems. Arch Pathol Lab Med.
    2009 Jun133(6)916-25.

43
Discussion
  • As for future research on information
    infrastructures for infectious disease response
    programs, studies are needed on
  • - how evidence is defined and revised as new
    infectious diseases progress, and
  • - how organizational and intellectual
    factors influence uptake of evidence in
    situations when the timeframe for taking
    preventive action is short (1).
  • To achieve this, methods for evidence syntheses
    in the areas of outbreak detection and predictive
    modeling need to be established, including
    definition of criteria for evaluation of study
    quality.
  • 1. Eccles MP, Armstrong D, Baker R, Cleary K,
    Davies H, Davies S, et al. An implementation
    research agenda. Implement Sci 2009418.

44
Conclusions
  • The PROSPER protocol has been drafted for
    establishment of evidence-based pandemic response
    also in developing countries with limited access
    to advanced technology.
  • The protocol is also useful because it
    facilitates the systematic study of the aspects
    of infrastructure and context that forms barriers
    to or facilitates response programs. In this way,
    existing and future information technologies can
    more effectively be summoned for analyses of new
    infectious diseases.
  • It is necessary to establish consensus guidelines
    specifically for reporting of evidence derived
    from predictive modeling related to infectious
    disease.
Write a Comment
User Comments (0)
About PowerShow.com