Penalized likelihood estimation of a trivariate additive probit model

This article proposes a penalized likelihood method to estimate a trivariate probit model, which accounts for several types of covariate effects (such as linear, nonlinear, random, and spatial effects), as well as error correlations. The proposed approach also addresses the difficulty in estimating accurately the correlation coefficients, which characterize the dependence of binary responses conditional on covariates. The parameters of the model are estimated within a penalized likelihood framework based on a carefully structured trust region algorithm with integrated automatic multiple smoothing parameter selection. The relevant numerical computation can be easily carried out using the SemiParTRIV() function in a freely available R package. The proposed method is illustrated through a case study whose aim is to model jointly adverse birth binary outcomes in North Carolina

Transfer of ultra-low phase noise microwave references over the JANET Aurora fibre network using a femtosecond optical frequency comb

An ultra-low phase noise microwave frequency is transferred over 82 km of installed fibre by propagation of a 30 nm bandwidth optical frequency comb (104 modes). The phase noise induced along the fibre by vibrations and thermal effects is suppressed by implementing a noise cancellation scheme where a portion of the light is sent back to the transmitter through the same fibre. The 6th harmonic of the repetition rate detected before and after the pulse train has travelled a round trip are phase compared and used to generate an error signal that controls a fibre stretcher to compensate for the fibre-induced phase fluctuations. Optical amplifiers are used to compensate for the fibre attenuation and dispersion compensation modules are also employed

Development of a grid-dispersion model in a large-eddy-simulation–generated planetary boundary layer

Numerical simulations of dispersion experiments within the planetary boundary layer are actually feasible making use of Large Eddy Simulations (LES). In Eulerian framework, a conservation equation for a passive scalar may be superimposed on LES wind/turbulence fields to get a realistic description of timevarying concentration field. Aim of this work is to present a numerical technique to solve the Eulerian conservation equation. The technique is based on Fractional Step/Locally One-Dimensional (LOD) methods. Advection terms are calculated with a semi-Lagrangian cubic-spline technique, while diffusive terms are calculated with Crank-Nicholson implicit scheme. To test the grid model, the dispersion of contaminants emitted from an elevated continuous point source in a convective boundary layer is simulated. Results show that the calculated concentration distributions agree quite well with numerical and experimental data found in the literature

High-resolution UAV imagery for field olive (Olea europaea L.) phenotyping

Remote sensing techniques based on images acquired from unmanned aerial vehicles (UAVs) could represent an effective tool to speed up the data acquisition process in phenotyping trials and, consequently, to reduce the time and cost of the field work. In this study, we assessed the ability of a UAV equipped with RGB-NIR cameras in highlighting differences in geometrical and spectral canopy characteristics between eight olive cultivars planted at different planting distances in a hedgerow olive orchard. The relationships between measured and estimated canopy height, projected canopy area and canopy volume were linear regardless of the different cultivars and planting distances (RMSE of 0.12 m, 0.44m2 and 0.68m3, respectively). Agood relationship (R2 = 0.95) was found between the pruning mass material weighted on the ground and its volume estimated by aerial images. NDVI measured in February 2019 was related to fruit yield per tree measured in November 2018, whereas no relationships were observed with the fruit yield measured in November 2019 due to abiotic and biotic stresses that occurred before harvest. These results confirm the reliability of UAV imagery and structure from motion techniques in estimating the olive geometrical canopy characteristics and suggest further potential applications of UAVs in early discrimination of yield efficiency between different cultivars and in estimating the pruning material volume

Modeling seasonal branch carbon dynamics in pistachio as a function of crop load

A simplified model for the prediction of carbon balance was developed to elucidate the seasonal trend of sink-source relationships in bearing and non-bearing pistachio (Pistacia vera L.) branches. Seasonal changes in growth rate of vegetative (leaf and shoot) and reproductive (infructescence) organs were monitored in branches of mature rainfed pistachio trees during the entire growing season (April–September). Simulations from the model were used to gain understanding of the implications of crop load on branch carbon (C) depletion and alternate bearing. Results showed that the pistachio branch was energetically able to sustain up to two infructescences (∼28 fruits) having a slightly positive carbon budget (2.6 g of C) at the end of the season. A branch with 4 infructescences (∼56 fruits) ended the season with a very negative carbon budget (-14.1 g of C) suggesting the implication of resource mobilization during heavy crop load. The simulations with the model allowed the identification of two energetically critical periods for pistachio, both characterized by a decreasing trend of the carbon budget. The first is at the beginning of the season, from leaf out until 35/40 days after full bloom (DAFB), when leaves are still not source of carbon, and the branch energetic need is largely satisfied by the remobilization of carbon from the reserves accumulated the previous year and stored through the winter. The second critical period is at the end of the season for bearing branches, at ∼100 DAFB, when a strong reduction in leaf area due to early leaf senescence and drop coincides with high carbon request for kernel growth. Overall, results demonstrate that the branch carbon budget model is a valid tool to study bearing dynamics in tree species and can help to develop physiologically-based management strategies for achieving increased and more constant productions in pistachio orchard systems

West Nile Virus and Wildlife Health

The West Nile Virus and Wildlife Health Workshop, hosted by the Smithsonian Institution, National Audubon Society, U.S. Geological Survey, and U.S. Department of Agriculture, was held February 5–7, 2003, at the Smithsonian Environmental Research Center in Edgewater, Maryland. The event was attended by more than 100 scientists, who heard 29 speakers and participated in strategy discussions during the 2-day meeting. The main focus of the conference was the present and future impact of West Nile virus on wildlife populations. Talks and discussions emphasized how basic research, public health, and land management can contribute to our understanding of the disease’s impact and spread. A primary objective of this meeting was to develop future research priorities from both basic and applied perspectives. The conference centered around four main themes: 1) host, vector, and pathogen interactions (disease ecology); 2) vertebrate behavior and ecology; 3) vector behavior and ecology; and 4) modeling and spatial statistics. We describe some of the findings from the meeting. For an in-depth summary of this meeting, please visit the conference website for meeting abstracts and a downloadable conference white paper (available from: URL: www.serc.si.edu/migratorybirds/ migratorybirds_index.htm)

Preoperative anxiety: What are we really doing?

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