1,875 research outputs found
Parameter Estimation of Gaussian Stationary Processes using the Generalized Method of Moments
We consider the class of all stationary Gaussian process with explicit
parametric spectral density. Under some conditions on the autocovariance
function, we defined a GMM estimator that satisfies consistency and asymptotic
normality, using the Breuer-Major theorem and previous results on ergodicity.
This result is applied to the joint estimation of the three parameters of a
stationary Ornstein-Uhlenbeck (fOU) process driven by a fractional Brownian
motion. The asymptotic normality of its GMM estimator applies for any H in
(0,1) and under some restrictions on the remaining parameters. A numerical
study is performed in the fOU case, to illustrate the estimator's practical
performance when the number of datapoints is moderate
From Digits to Diagrams: Using Infographics to Inform Database Retention and Cancellation Decisions
This paper describes a poster presentation about how Ithaca College librarians used an infographic displaying the relationships among databases to make retention and cancellation decisions for the 2013–2014 fiscal year. The diagram, which was created to help selectors more easily understand how canceling one database would affect subscriptions to other databases, also shows the impact of the resources’ interconnectedness on cost. A modified sample of the illustration is reproduced in this report. Design considerations and the tools used to create the image will also be discussed
Biofouling in the Southern Caspian Sea: recruitment and successional patterns in a low diversity region
Abstract
Biofouling is predicted to increase in the course of global warming, making the study and monitoring of its ecological and economic consequences of great importance. The present study describes, for the first time, recruitment and successional patterns of fouling communities in the Caspian Sea. During one year, short-term panels (STP; replaced every 2 months) and long-term panels (LTP; retrieved after 4, 8 and 12 months) were deployed in the Western Iranian coast of the Caspian Sea. Temporal trends in both sets of panels were evaluated through Generalized Additive Models and discussed in light of the environmental variables registered in each sampling event. Recruitment and successional patterns observed at the community level were mainly driven by barnacles and bryozoans, the dominant taxa over the entire sampling period. Panel coverage, biomass and inorganic to organic matter ratio exhibited clear seasonal patterns in STP, following temperature and chlorophyll a trends. In LTP, coverage and biomass increased over the study period, while the inorganic to organic matter ratio peaked in summer and decreased during autumn and winter months. These results represent a baseline for future studies on biofouling communities in the Caspian Sea, where this topic has been completely neglected
Forecasting hospital discharges for respiratory conditions in Costa Rica using climate and pollution data
Respiratory diseases represent one of the most significant economic burdens
on healthcare systems worldwide. The variation in the increasing number of
cases depends greatly on climatic seasonal effects, socioeconomic factors, and
pollution. Therefore, understanding these variations and obtaining precise
forecasts allows health authorities to make correct decisions regarding the
allocation of limited economic and human resources. This study aims to model
and forecast weekly hospitalizations due to respiratory conditions in seven
regional hospitals in Costa Rica using four statistical learning techniques
(Random Forest, XGboost, Facebook's Prophet forecasting model, and an ensemble
method combining the above methods), along with 22 climate change indices and
aerosol optical depth as an indicator of pollution. Models are trained using
data from 2000 to 2018 and are evaluated using data from 2019 as testing data.
Reliable predictions are obtained for each of the seven regional hospital
Desinfestação de explantes foliares de caju e graviola para cultivo in vitro.
bitstream/item/35443/1/f-02.pd
"Eficacia de los programas de tratamiento para ciberadicción en niños y adolescentes: revisión sistemática y meta-análisis "
"El objetivo de este estudio fue evaluar la eficacia de los programas de
tratamiento para la ciberadicción en niños y adolescentes. Material y Métodos: Se
realizó la búsqueda en cinco bases de datos. Se seleccionaron ensayos controlados
aleatorizados (ECA) o estudios de cohorte que evaluaron la eficacia de programas de
tratamiento para la ciberadicción en niños y adolescentes. El desenlace primario fue la
disminución de las horas en uso del internet. Para el meta-análisis, se utilizó el modelo
de efectos aleatorios con método de varianza inversa. Resultados: Se identificaron siete
artÃculos que fueron incluidos en la revisión sistemática (3 Ensayos controlados
aleatorizados y 4 cohortes retrospectivas), con un total de 2396 participantes. La edad
media fue de 14 años (SD 1.96). La duración del tratamiento entre todos los estudios
publicados varió entre 4 dÃas hasta los 3 meses. Se encontró que los tratamientos para la
ciberadicción reducen las horas de conexión a internet en 1.18 horas por semana,
comparado con cualquier tratamiento de control (MD 1.18; 95%CI -2.1825 a -0.1754; p=
0.02). Conclusiones: Los tratamientos para la ciberadicción, independientemente del tipo
de intervención reducen las horas de conexión a internet
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