BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Yoh Iwasa (Kwansei Gakuin University)
DTSTART;VALUE=DATE-TIME:20210125T201000Z
DTEND;VALUE=DATE-TIME:20210125T205500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/1
DESCRIPTION:Title: Persistence of corruption: an evolutionary game theory motivated by i
llegal logging in tropics\nby Yoh Iwasa (Kwansei Gakuin University) as
part of BIRS workshop: Mathematics of Human Environmental Systems\n\n\nAb
stract\nIllegal logging is a serious threat to plantations in the tropics.
Here\, we study the coupled dynamics of Social-Ecological systems sheddin
g light of two different aspects.\n[1] We examined the roles of profit-sha
ring in plantation management strategy in a dynamic game model. The model
assumes that the owner chooses the age of the trees to be harvested and th
e local people choose their level of monitoring effort to prevent illegal
logging with surveillance. After the trees are removed\, the owner hires l
ocal people to replant young trees. Dynamic optimization analysis revealed
that\, under the pressure of illegal logging\, the owner may find it prof
itable to share harvesting profits with the local people to enhance their
surveillance effort. The profit-sharing rate optimal to the owner depends
on the rate of natural disturbance\, faster future discount rate\, and a h
igher cost of replanting.\n[2] Cooperation can be sustained by institution
s that punish free-riders. Such institutions\, however\, tend to be subver
ted by corruption if they are not closely watched. Monitoring can uphold t
he enforcement of binding agreements ensuring cooperation\, but this usual
ly comes at a price. The temptation to skip monitoring and take the instit
ution’s integrity for granted leads to outbreaks of corruption and the b
reakdown of cooperation. We model the corresponding mechanism by means of
evolutionary game theory\, using analytical methods and numerical simulati
ons\, and find that it leads to sustained or damped oscillations. The resu
lts confirm the view that corruption is endemic and transparency a major f
actor in reducing it.\nLee\, J-H.\, Y. Kubo\, T. Fujiwara\, R.M. Septianad
\, S. Riyantod\, and Y. Iwasa. 2018. Profit sharing as a management strate
gy for a state-owned teak plantation at high risk for illegal logging. Eco
logical Economics 149\, 140-148.\nLee\, J-H\, Y. Iwasa\, U. Dieckmann\, an
d K. Sigmund. 2019 Social evolution leads to persistent corruption. PNAS 1
16\, 13276-13281.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Heggerud (University of Alberta)
DTSTART;VALUE=DATE-TIME:20210125T210000Z
DTEND;VALUE=DATE-TIME:20210125T213000Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/2
DESCRIPTION:Title: Christopher Heggerud: Coupling the socio-economic and ecological dyna
mics of cyanobacteria\nby Christopher Heggerud (University of Alberta)
as part of BIRS workshop: Mathematics of Human Environmental Systems\n\n\
nAbstract\nCyanobacterial (CB) blooms are becoming a global concern due to
the increasing prevalence of eutrophication. The dependence of CB dynamic
s on phosphorus and light inputs is modeled via a stoichiometric approach
and the transient dynamics are discussed. We then couple the CB model to a
socio-economic model governing the anthropogenic nutrient inputs. We assu
me that the human population is made up of cooperators and defectors and t
hat each strategy has an associated cost dependent on social pressure and
norms\, concern for CB\, and effort. We find that the human population at
a single lake exhibits bistability. Further\, in considering a network of
lakes the level of cooperation is highly dependent on social norms.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eli Fenichel (Yale University)
DTSTART;VALUE=DATE-TIME:20210125T220000Z
DTEND;VALUE=DATE-TIME:20210125T224500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/3
DESCRIPTION:Title: Eli Fenichel: Getting human behavior into epidemiology models\nby
Eli Fenichel (Yale University) as part of BIRS workshop: Mathematics of H
uman Environmental Systems\n\n\nAbstract\nInfectious disease modeling effo
rts are emblematic of the challenges of modeling coupled human-environment
al systems. These challenges exist conceptually\, theoretically\, and empi
rically\, and are made more challenging by disciplinary norms. COVID-19 ha
s pumped substantial amounts of energy into interdisciplinary and multidis
ciplinary approaches to epidemiological modeling. However\, I see many of
the over-simplifications\, related to challenges we have struggled with fo
r over 10 years\, finding their way into high profile reports and publicat
ions that are guiding policy response. The challenges start with implicit
disciplinary disagreement about what is being modeled and why. They are fu
rther complicated by scaling issues\, which are tightly connected to disci
plinary views of model assessment that point back to the reasons for model
ing. In this talk\, I will describe my lessons learned and outline a resea
rch program for couple human-epidemiological modeling going forward with t
he goal of providing insights for other human-environmental modeling and f
or public health.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rebecca Tyson (University of British Columbia - Okanagan)
DTSTART;VALUE=DATE-TIME:20210125T225000Z
DTEND;VALUE=DATE-TIME:20210125T232000Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/4
DESCRIPTION:Title: Rebecca Tyson: CHANS with Opinion Dynamics\nby Rebecca Tyson (Uni
versity of British Columbia - Okanagan) as part of BIRS workshop: Mathemat
ics of Human Environmental Systems\n\n\nAbstract\nCHANS models frequently
incorporate the human component using a game theoretic framework. In this
work\, we present a different approach where opinion dynamics are modeled
explicitly\, giving us access to social behaviours such as amplification a
nd polarization. We study the behaviour of the opinion dynamics in isolati
on\, and then couple them to disease dynamics to study the interaction\nbe
tween the two. We propose that our approach allows for the inclusion of hu
man behaviours that are difficult to access via traditional CHANS modellin
g\, and that might have important consequences for the management of ecolo
gical systems.\nCo-Authors: Noah Marshall\, Stephen M. Krone\, Bert O. Bau
mgaertner\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frank Hilker (Osnabrück University)
DTSTART;VALUE=DATE-TIME:20210126T200000Z
DTEND;VALUE=DATE-TIME:20210126T204500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/6
DESCRIPTION:Title: Comparison between best-response dynamics and replicator dynamics in
a social-ecological model of lake eutrophication\nby Frank Hilker (Osn
abrück University) as part of BIRS workshop: Mathematics of Human Environ
mental Systems\n\n\nAbstract\nHuman behavior can be modeled by describing\
, on a collective level\, the adoption of certain strategies by individual
agents. Many models use either the replicator dynamics (RD) or the logit
formulation of the best-response (BR). How do RD and BR differ\, and does
the distinction matter? This talk gives a brief overview of the two behavi
oral models\, both of which originate from evolutionary game theory. Their
differences are illustrated in the context of a social-ecological model f
or eutrophication in shallow lakes\, where the anthropogenic discharge of
pollutants into the water is determined by RD or BR. It will be shown that
the replicator equation is a limit case of the best-response model\, when
agents are assumed to behave with infinite rationality. If agents act les
s rationally in BR\, the correspondence with RD decreases\; the two model
versions can differ substantially regarding the number of possible equilib
ria\, the potential for multistability\, and the type of sustained oscilla
tions. Consequently\, the choice of the behavioral model may profoundly af
fect the overall dynamics of a coupled human-environment system and deserv
es careful consideration. Joint work with Anthony Sun\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mayuko Nakamaru (Tokyo Institute of Technology)
DTSTART;VALUE=DATE-TIME:20210126T205000Z
DTEND;VALUE=DATE-TIME:20210126T213500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/7
DESCRIPTION:Title: Ecological features benefiting sustainable harvesters in socio-ecolog
ical systems: A case study of swiftlets in Malaysia\nby Mayuko Nakamar
u (Tokyo Institute of Technology) as part of BIRS workshop: Mathematics of
Human Environmental Systems\n\n\nAbstract\nIf sustainable harvesters coul
d benefit more than the unsustainable ones\, even in the short term\, the
overharvesting problem in ecosystem would be solved. However\, it is not a
n easy task. There is a special case: swiftlets in Sarawak\, Malaysia\, wh
ere sustainable harvesters are believed to obtain a more return than unsus
tainable harvesters in the short term. Edible nests built by adult swiftle
ts are used as ingredients for a Chinese traditional soup. There is a loca
l knowledge that\, once unsustainable harvesters harvest the nests on the
cave ceilings\, swiftlets escape from the cave and never come back to the
same place. This ecological behavior works as the swiftlet's indirect puni
shment against unsustainable harvesters. We make a stage-structured popula
tion model and examines the effect of property rights and the indirect pun
ishment by swiftlets on the population dynamics of the swiftlets\, and on
the short-term return of both sustainable and unsustainable harvesters. Fo
llowing are our findings: both the indirect punishment by swiftlets and th
e property rights system are required to provide sustainable harvesters wi
th a higher short-term return than unsustainable harvesters. We would like
to discuss the possibility to apply this model to other ecosystem managem
ents.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Akiko Satake (Kyushu University)
DTSTART;VALUE=DATE-TIME:20210126T220500Z
DTEND;VALUE=DATE-TIME:20210126T225000Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/8
DESCRIPTION:Title: Coupled social and ecological systems in forested landscape\nby A
kiko Satake (Kyushu University) as part of BIRS workshop: Mathematics of H
uman Environmental Systems\n\n\nAbstract\nLandscape change is the outcome
of both natural and anthropogenic disturbances. Natural disturbances (e.g.
\, forest fires\, land slides\, and floods) are episodic and stochastic ev
ents that occur across a wide range of spatial and temporal scales. Anthro
pogenic disturbances (e.g.\, forest clearance for agriculture\, timber har
vest\, or pasture) also occur at various temporal and spatial scales\, but
often at a faster rate and a more extensive scale than natural disturbanc
es. Deforestation is especially an important environmental problem because
of its impact on biodiversity\, carbon cycling associated with global cli
mate\, biogeochemical cycling\, and other ecosystem functions. A key facto
r inducing landscape change is the human behavior that underlies these cha
nges. The simplest way to consider this is to develop a model which traces
the responses of landowners to the change of socioeconomic and ecological
conditions. We introduce a Markov chain model for land-use dynamics in a
forested landscape [1─4]. The model emphasizes the importance of couplin
g socioeconomic and ecological processes underlying landscape changes. \n\
nReferences\n[1] Satake A\, Iwasa Y (2006) Coupled ecological and social d
ynamics in a forested landscape: the deviation of the individual decisions
from the social optimum. Ecological Research 21\, 370–379.\n[2] Satake
A\, Rudel TK (2007) Modelling the forest transition: forest scarcity and e
cosystem service hypotheses. \nEcological Applications 17\, 2024–2036.\n
[3] Satake A\, Janssen MA\, Levin SA\, Iwasa Y (2007) Collective deforesta
tion induced by social learning under uncertainty of forest-use value. \nE
cological Economics 63\, 452–462.\n[4] Satake A\, Rudel TK\, Onuma A (20
08) Scale mismatches and their ecological and economic effects on landscap
es: a spatially explicit model. \nGlobal Environmental Change 18\, 768–7
75.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alan Hastings (University of California - Davis)
DTSTART;VALUE=DATE-TIME:20210127T200000Z
DTEND;VALUE=DATE-TIME:20210127T204500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/10
DESCRIPTION:Title: Role of Transients in Human Environmental Systems\nby Alan Hasti
ngs (University of California - Davis) as part of BIRS workshop: Mathemati
cs of Human Environmental Systems\n\n\nAbstract\nI will show how understan
ding transient behavior is important in the management of ecological syste
ms and discuss recent results that provide a general framework for underst
anding transient dynamics. The simplest transients arise in linear system
s\, where the cessation of fishing after implementation of a marine reserv
e provides an example which is both illustrative and important. I will di
scuss how dynamics after or near a ‘tipping point’ are another key exa
mple. More generally\, I will show how human-environmental systems are ty
pically a mix of different time scales which makes transients likely. I w
ill emphasize how the need to understand dynamics on different time scales
makes an understanding of transients essential\, and illustrate this and
other aspects with examples.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Bauch (University of Waterloo)
DTSTART;VALUE=DATE-TIME:20210127T205000Z
DTEND;VALUE=DATE-TIME:20210127T213500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/11
DESCRIPTION:Title: Early warning signals of critical transitions in coupled human-envir
onment systems: leveraging data science with dynamical systems\nby Chr
is Bauch (University of Waterloo) as part of BIRS workshop: Mathematics of
Human Environmental Systems\n\n\nAbstract\nModelling coupled human-enviro
nment systems is becoming an increasingly urgent research priority. Coupli
ng human dynamics to environmental dynamics in mathematical models introdu
ces higher dimensionality and thus novel dynamics. This creates both chal
lenges and opportunities for predicting critical transitions with early wa
rning signals based on effects like critical slowing down. In this talk\,
I will summarize work that shows how feedback from human systems can muff
le early warning signals of collapse in an environmental system\; how feed
back can ‘doom’ a human-environment system to self-evolved criticality
\; how timescale differences mean that early warning signals of human-envi
ronment collapse can be more apparent in the human system than the environ
ment system\; and how machine learning algorithms\, in concert with dynami
cal systems insights\, can be used to enhance our ability to provide early
warning of such transitions.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrew Tilman (University of Pennsylvania)
DTSTART;VALUE=DATE-TIME:20210127T220500Z
DTEND;VALUE=DATE-TIME:20210127T225000Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/12
DESCRIPTION:Title: Environmental forecasting and human-environmental dynamics\nby A
ndrew Tilman (University of Pennsylvania) as part of BIRS workshop: Mathem
atics of Human Environmental Systems\n\n\nAbstract\nEco-evolutionary game
theory provides a framework for the analysis of human-environmental dynami
cs. In an eco-evolutionary game\, strategies of individuals impact the env
ironment and the state of the environment alters the payoff structure that
individuals face\, generating feedback. This feedback can lead to persist
ent cyclical environmental overshoot. In the model of eco-evolutionary gam
es that I will present\, we examine the impact of environmental forecastin
g on cyclic human-environmental dynamics. We find that if individuals make
forecasts of the environment and integrate these forecasts into their str
ategy updating process\, environmental stability can be achieved. Next\, I
will share a model of competition between forecasting and non-forecasting
types in a human-environmental system to explore whether forecasting type
s can invade and generate environmental stability. \nCoauthors: Vitor Vasc
oncelos\, Erol Akcay\, Joshua Plotkin\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nina Fefferman (University of Tennessee)
DTSTART;VALUE=DATE-TIME:20210128T200000Z
DTEND;VALUE=DATE-TIME:20210128T204500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/14
DESCRIPTION:Title: Humans as Ecosystem Engineers of the Pathogen Landscape\nby Nina
Fefferman (University of Tennessee) as part of BIRS workshop: Mathematics
of Human Environmental Systems\n\n\nAbstract\nHumans shape nearly every a
spect of our environment\, from purposeful elimination of rural predators
to the altered soil chemistry of urban settings. These changes have both d
irect and indirect effects on the evolution and ecology of pathogens. In t
his talk\, we will touch briefly on the obvious\, direct efforts to contro
l pathogen systems (e.g.\, antibiotics use) and then spend the majority of
time discussing indirect impacts of modern human systems that can profoun
dly impact the evolution and ecology of pathogens. We will discuss a few t
oy models that highlight these effects and discuss a potential framework f
or understanding the cascading impacts and bidirectional feedbacks between
humans and the pathogen landscape in which we live.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junling Ma (University of Victoria)
DTSTART;VALUE=DATE-TIME:20210128T205000Z
DTEND;VALUE=DATE-TIME:20210128T213500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/15
DESCRIPTION:Title: Time of infections of SI epidemics on networks of cities\, farms\, o
r individual\nby Junling Ma (University of Victoria) as part of BIRS w
orkshop: Mathematics of Human Environmental Systems\n\n\nAbstract\nA novel
probabilistic approach is presented for obtaining the probability distrib
u- tion of infection time for SI disease epidemics on a finite network spe
cified as a fixed weighted digraph. Individuals (network nodes) are classi
fied as either susceptible or infectious\, with transmission rates along w
eighted network arcs. The model is ap- propriate for diseases with no reco
very\, or for the initial outbreak of diseases with recovery. Our method t
o analyze the model yields the exact probability distribution for the time
at which a given individual in the network becomes infected. This can als
o be used to compute the probability that any given individual is infected
as well as the expected number of infectious individuals at any time. Exa
mples of simple networks illustrate the utility of the method. Nodes can a
lso be identified more generally\, such as farms or cities\, and the metho
d can be applied to biological networks with estimated transmission rates
on the network arcs.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Finnoff (University of Wyoming)
DTSTART;VALUE=DATE-TIME:20210128T220500Z
DTEND;VALUE=DATE-TIME:20210128T225000Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/16
DESCRIPTION:Title: Human behavior in economic-epidemiological systems\nby David Fin
noff (University of Wyoming) as part of BIRS workshop: Mathematics of Huma
n Environmental Systems\n\n\nAbstract\nWe investigate the dynamics of epid
emiological bifurcations in systems where individuals optimally alter beha
vior in the face of endogenous disease risk. The bifurcations can lead to
aggregate instability\, which introduces the potential for less predictabl
e outcomes from public health policies and welfare losses. For instance\,
health policies designed to lower the transmission probability or policies
designed to raise the quality-of-life following infection generate endoge
nous human responses that may push endemic equilibria from being stable to
exhibiting instability or indeterminacy with the possibility of unintende
d consequences from public health policy.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Madhur Anand (University of Guelph)
DTSTART;VALUE=DATE-TIME:20210129T200000Z
DTEND;VALUE=DATE-TIME:20210129T204500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/18
DESCRIPTION:Title: What can we learn from mathematical models of ourselves? Examples fr
om forest pest spread to climate change mitigation.\nby Madhur Anand (
University of Guelph) as part of BIRS workshop: Mathematics of Human Envir
onmental Systems\n\n\nAbstract\nIt is becoming increasingly clear that hum
ans and ecosystems form a single\, coupled human-environment system (HES)
where humans not only cause negative ecosystem impacts\, but also react to
them. Humans have highly diverse identities and complex social structures
that affect our decision-making. We also have the ability to modify our e
nvironments (and those of other organisms) in ways fundamentally different
from what other organisms do. This can lead to shifts in norms in how hum
ans use\, abuse and/or protect ecological systems and in turn feedback on
human behaviour. Despite this\, there are still far fewer examples of cou
pled mathematical models of human and ecological systems than mathematical
models of ecological systems themselves. We will present recent case stu
dies in human-environment systems from our own work in forest pest and cli
mate change mitigation. I discuss the challenges of this kind of research
and suggest areas and pathways through which mathematical models of human-
environment sustainability could be enhanced in future research.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Louis Gross (University of Tennessee\, Knoxville)
DTSTART;VALUE=DATE-TIME:20210129T205000Z
DTEND;VALUE=DATE-TIME:20210129T213500Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/19
DESCRIPTION:Title: A Rational Basis for Hope: Human Behavior Modeling and Climate Chang
e\nby Louis Gross (University of Tennessee\, Knoxville) as part of BIR
S workshop: Mathematics of Human Environmental Systems\n\n\nAbstract\nWhil
e climate models have rapidly advanced in sophistication over recent decad
es\, they lack dynamic representation of human behavior and social systems
despite strong feedbacks between social processes and climate. The impact
s of climate change alter perceptions of risk and emissions behavior that\
, in turn\, influence the rate and magnitude of climate change. Addressing
this deficiency in climate models requires a substantial interdisciplinar
y effort to couple models of climate and\nhuman behavior. I will discuss e
fforts by a group of highly-interdisciplinary collaborators to create link
ed models of human behavior\, risk perception and global climate. Our resu
lts indicate that\ninclusion of human behavioral change arising from the p
erception and experience of extreme events could have large impacts on tem
perature trajectories. Furthermore\, uncertainties in global temperature t
rajectories arising from impacts of human behavior are similar in magnitud
e to those arising from uncertainties of the physical components of climat
e models.\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hans Kaper (Georgetown University)
DTSTART;VALUE=DATE-TIME:20210129T220500Z
DTEND;VALUE=DATE-TIME:20210129T225000Z
DTSTAMP;VALUE=DATE-TIME:20240328T123046Z
UID:BIRS_21w5191/20
DESCRIPTION:Title: Modeling Food System\nby Hans Kaper (Georgetown University) as p
art of BIRS workshop: Mathematics of Human Environmental Systems\n\n\nAbst
ract\nThe agricultural establishment has made significant progress in its
efforts to improve agricultural productivity and efficiency. Yet\, with ab
out one billion people hungry\, two billion people with insufficient nutri
ents\, and over two billion people already overweight or obese\, undernutr
ition and malnutrition are affecting more than half the world's population
. Clearly\, when enough food is produced but sizable fractions of the popu
lation suffer from malnutrition or are overweight\, we need to get a bette
r understanding of the global food system. In this talk\, I will describe
some recent efforts at modeling food systems and highlight research issue
s for MPE. \n(Joint work with Hans Engler\, Georgetown University)\n
LOCATION:https://researchseminars.org/talk/BIRS_21w5191/20/
END:VEVENT
END:VCALENDAR