946 research outputs found
Amigo guardaparque : una propuesta de identidad, modelo de sesión de aprendizaje y componentes de un kit de materiales de educación ambiental para el bosque de protección del Alto Mayo - San Martín, aplicando design thinking
Aproximadamente el 60% del territorio peruano está cubierto de bosques, sin
embargo, la mayor cantidad de gases de efecto invernadero producida (35%), proviene la
liberación del carbono generado por la tala y quema de estos. El Bosque de Protección Alto
Mayo (BPAM), Área Natural Protegida por el Estado (ANP) donde se lleva a cabo esta
investigación, no es ajeno a esta realidad; la deforestación es realizada principalmente para
instalar cultivos de café por agricultores migrantes, quienes llegan en busca de tierras fértiles
y nuevos medios de vida; además de taladores y traficantes de tierras quienes son los
causantes de los conflictos sociales dentro del área protegida. La importancia del BPAM
como ANP radica en que es la fuente principal de servicios ecosistémicos para la población
del Alto Mayo (brinda agua a más de 250 mil personas), sin embargo, la población asentada
dentro del área y en su zona de amortiguamiento no tiene conocimiento de lo importante que
es conservar el bosque para su propio beneficio a largo plazo, y realiza prácticas agrícolas y
ganaderas que afectan el bosque.
Ante esta amenaza, el Servicio de Áreas Naturales Protegidas del Perú (SERNANP),
a través de su Plan Maestro, estableció como uno de sus componentes para alcanzar sus
objetivos de conservación, la educación ambiental; sin embargo, la Jefatura del BPAM no
cuenta con un área de educación ambiental ni una estrategia a largo plazo; esta labor ha caído
en los guardaparques quienes, además de su función principal de Control y Vigilancia del
área, cumplen con la función de educadores ambientales en los colegios de primaria dentro
del bosque. A pesar de tener esta responsabilidad, los guardaparques no cuentan con los
materiales educativos adecuados para desarrollar esta función; los materiales disponibles son
escasos, están desactualizados o no están hechos para las necesidades de los usuarios y esto
dificulta tanto la labor educativa de los guardaparques, como el aprendizaje en los niños.
Frente a esta realidad tan compleja, la presente investigación aplica el design thinking
como herramienta que ayude a comprender el problema de diseño para llegar a soluciones
de manera participativa con las personas que son parte de este. El proyecto “AMIGO
GUARDAPARQUE” propone la creación de una nueva identidad para el trabajo de
educación ambiental que realizan los guardaparques, un modelo de sesión lúdico didáctica,
y una propuesta de elementos de un kit de educación ambiental.Tesi
Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment
The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410
has been developed by Hamamatsu for dark matter direct detection experiments
using liquid xenon as the target material. We present the results from the
joint effort between the XENON collaboration and the Hamamatsu company to
produce a highly radio-pure photosensor (version R11410-21) for the XENON1T
dark matter experiment. After introducing the photosensor and its components,
we show the methods and results of the radioactive contamination measurements
of the individual materials employed in the photomultiplier production. We then
discuss the adopted strategies to reduce the radioactivity of the various PMT
versions. Finally, we detail the results from screening 216 tubes with
ultra-low background germanium detectors, as well as their implications for the
expected electronic and nuclear recoil background of the XENON1T experiment.Comment: 10 pages, 5 figure
Search for Event Rate Modulation in XENON100 Electronic Recoil Data
We have searched for periodic variations of the electronic recoil event rate
in the (2-6) keV energy range recorded between February 2011 and March 2012
with the XENON100 detector, adding up to 224.6 live days in total. Following a
detailed study to establish the stability of the detector and its background
contributions during this run, we performed an un-binned profile likelihood
analysis to identify any periodicity up to 500 days. We find a global
significance of less than 1 sigma for all periods suggesting no statistically
significant modulation in the data. While the local significance for an annual
modulation is 2.8 sigma, the analysis of a multiple-scatter control sample and
the phase of the modulation disfavor a dark matter interpretation. The
DAMA/LIBRA annual modulation interpreted as a dark matter signature with
axial-vector coupling of WIMPs to electrons is excluded at 4.8 sigma.Comment: 6 pages, 4 figure
Search for Two-Neutrino Double Electron Capture of Xe with XENON100
Two-neutrino double electron capture is a rare nuclear decay where two
electrons are simultaneously captured from the atomic shell. For Xe
this process has not yet been observed and its detection would provide a new
reference for nuclear matrix element calculations. We have conducted a search
for two-neutrino double electron capture from the K-shell of Xe using
7636 kgd of data from the XENON100 dark matter detector. Using a
Bayesian analysis we observed no significant excess above background, leading
to a lower 90 % credibility limit on the half-life
yr. We also evaluated the sensitivity of the XENON1T experiment, which is
currently being commissioned, and find a sensitivity of
yr after an exposure of 2 tyr.Comment: 6 pages, 4 figure
Removing krypton from xenon by cryogenic distillation to the ppq level
The XENON1T experiment aims for the direct detection of dark matter in a
cryostat filled with 3.3 tons of liquid xenon. In order to achieve the desired
sensitivity, the background induced by radioactive decays inside the detector
has to be sufficiently low. One major contributor is the -emitter
Kr which is an intrinsic contamination of the xenon. For the XENON1T
experiment a concentration of natural krypton in xenon Kr/Xe < 200
ppq (parts per quadrillion, 1 ppq = 10 mol/mol) is required. In this
work, the design of a novel cryogenic distillation column using the common
McCabe-Thiele approach is described. The system demonstrated a krypton
reduction factor of 6.410 with thermodynamic stability at process
speeds above 3 kg/h. The resulting concentration of Kr/Xe < 26 ppq
is the lowest ever achieved, almost one order of magnitude below the
requirements for XENON1T and even sufficient for future dark matter experiments
using liquid xenon, such as XENONnT and DARWIN
Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron
We study the underlying event in proton-antiproton collisions by examining
the behavior of charged particles (transverse momentum pT > 0.5 GeV/c,
pseudorapidity |\eta| < 1) produced in association with large transverse
momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the
Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV
center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan
production) or the leading jet (in high-pT jet production) in each event to
define three regions of \eta-\phi space; toward, away, and transverse, where
\phi is the azimuthal scattering angle. For Drell-Yan production (excluding the
leptons) both the toward and transverse regions are very sensitive to the
underlying event. In high-pT jet production the transverse region is very
sensitive to the underlying event and is separated into a MAX and MIN
transverse region, which helps separate the hard component (initial and
final-state radiation) from the beam-beam remnant and multiple parton
interaction components of the scattering. The data are corrected to the
particle level to remove detector effects and are then compared with several
QCD Monte-Carlo models. The goal of this analysis is to provide data that can
be used to test and improve the QCD Monte-Carlo models of the underlying event
that are used to simulate hadron-hadron collisions.Comment: Submitted to Phys.Rev.
Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV
We search for the standard model Higgs boson produced in association with an
electroweak vector boson in events with no identified charged leptons, large
imbalance in transverse momentum, and two jets where at least one contains a
secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1
integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV
recorded by the CDF II experiment at the Tevatron. We find 268 (16) single
(double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are
expected from standard model background processes. We place 95% confidence
level upper limits on the Higgs boson production cross section for several
Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115
GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model
prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let
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