Stopping rule sampling to monitor and protect endangered species

Ecological science and management often require animal population abundance estimates to determine population status, set harvest limits on exploited populations, assess biodiversity, and evaluate the effects of management actions. However, sampling can harm animal populations. Motivated by trawl sampling of an endangered fish, we present a sequential adaptive sampling design focused on making population-level inferences while limiting harm to the target population. The design incorporates stopping rules such that multiple samples are collected at a site until one or more individuals from the target population are captured, conditional on the number of samples falling within a predetermined range. With this application in mind, we pair the stopping rules sampling design with a density model from which to base abundance indices. We use theoretical analyses and simulations to evaluate inference of population parameters and reduction in catch under the stopping rule sampling design compared to fixed sampling designs. Density point estimates based on stopping rules could theoretically be biased high, but simulations indicated that the stopping rules did not induce noticeable bias in practice. Retrospective analysis of the case study indicated that the stopping rules reduced catch by 60% compared to a fixed sampling design with maximum possible effort

Association of Cow and Quarter Level Factors at Dry Off and New Intramammary Infections in the Dry Period

Data from 300 cows and 1,178 quarters were analyzed to determine factors associated with new dry period intramammary infections (IMI). Teat-ends that were cracked and teats that did not close during the dry period were 1.7 and 1.8 times more likely to develop new IMI, respectively. The level of milk production on the last day of lactation significantly influenced new IMI and teat canal closure. More (P\u3c0.05) cows (36%) producing 21 kg of milk developed new IMI than cows (18%) producing less. When milk production was 21 kg or higher, teat canals were 1.8 times more likely to remain open. These data provide new insight into mastitis risk factors and new management areas for cows prior to dry off

Evaluation of the California Mastitis Test to Determine Udder Health Status of Early Lactation Dairy Cows

Quarter milk bacteriology results of samples collected within the first week of calving were used to calculate the test characteristics of the California Mastitis Test (CMT) that estimate the udder health status of fresh dairy cows. Over 1,200 quarters were both cultured and had a CMT performed. The overall sensitivity and specificity of the CMT was 68.8% and 71.5%, respectively. Using a cutpoint of any CMT reaction as a positive test, and examining the results by various days in milk, the highest sensitivity and specificity occurred at day four (82.4% and 80.6%, respectively). The CMT has the potential to be useful tool for monitoring udder health in fresh cows

A non-invasive method for nanoscale electrostatic gating of pristine materials

Electrostatic gating is essential for defining and control of semiconducting devices. However, nano-fabrication processes required for depositing gates inevitably degrade the pristine quality of the material of interest. Examples of materials that suffer from such degradation include ultra-high mobility GaAs/AlGaAs two-dimensional electron gases (2DEGs), graphene, topological insulators, and nanowires. To preserve the pristine material properties, we have developed a flip-chip setup where gates are separated from the material by a vacuum, which allows nanoscale electrostatic gating of the material without exposing it to invasive nano-processing. An additional benefit is the vacuum between gates and material, which, unlike gate dielectrics, is free from charge traps. We demonstrate the operation and feasibility of the flip-chip setup by achieving quantum interference at integer quantum Hall states in a Fabry-P\'erot interferometer based on a GaAs/AlGaAs 2DEG. Our results pave the way for the study of exotic phenomena including fragile fractional quantum Hall states by preserving the high quality of the material.Comment: 25 pages including Supporting Informatio