219 research outputs found

    Applications in adaptive cluster sampling of Gulf of Alaska rockfish

    Get PDF
    Adaptive cluster sampling (ACS) has been the subject of many publications about sampling aggregated populations. Choosing the criterion value that invokes ACS remains problematic. We address this problem using data from a June 1999 ACS survey for rockfish, specifically for Pacific ocean perch (Sebastes alutus), and for shortraker (S. borealis) and rougheye (S. aleutianus) rockfish combined. Our hypotheses were that ACS would outperform simple random sampling (SRS) for S. alutus and would be more applicable for S. alutus than for S. borealis and S. aleutianus combined because populations of S. alutus are thought to be more aggregated. Three alternatives for choosing a criterion value were investigated. We chose the strategy that yielded the lowest criterion value and simulated the higher criterion values with the data after the survey. Systematic random sampling was conducted across the whole area to determine the lowest criterion value, and then a new systematic random sample was taken with adaptive sampling around each tow that exceeded the fixed criterion value. ACS yielded gains in precision (SE) over SRS. Bootstrapping showed that the distribution of an ACS estimator is approximately normal, whereas the SRS sampling distribution is skewed and bimodal. Simulation showed that a higher criterion value results in substantially less adaptive sampling with little tradeoff in precision. When time-efficiency was examined, ACS quickly added more samples, but sampling edge units caused this efficiency to be lessened, and the gain in efficiency did not measurably affect our conclusions. ACS for S. alutus should be incorporated with a fixed criterion value equal to the top quartile of previously collected survey data. The second hypothesis was confirmed because ACS did not prove to be more effective for S. borealis-S. aleutianus. Overall, our ACS results were not as optimistic as those previously published in the literature, and indicate the need for further study of this sampling method

    Smartphone assessment of knee flexion compared to radiographic standards

    Get PDF
    Purpose—Measuring knee range of motion (ROM) is an important assessment for the outcomes of total knee arthroplasty. Recent technological advances have led to the development and use of accelerometer-based smartphone applications to measure knee ROM. The purpose of this study was to develop, standardize, and validate methods of utilizing smartphone accelerometer technology compared to radiographic standards, visual estimation, and goniometric evaluation. Methods—Participants used visual estimation, a long-arm goniometer, and a smartphone accelerometer to determine range of motion of a cadaveric lower extremity; these results were compared to radiographs taken at the same angles. Results—The optimal smartphone position was determined to be on top of the leg at the distal femur and proximal tibia location. Between methods, it was found that the smartphone and goniometer were comparably reliable in measuring knee flexion (ICC = 0.94; 95% CI: 0.91–0.96). Visual estimation was found to be the least reliable method of measurement. Conclusions—The results suggested that the smartphone accelerometer was non-inferior when compared to the other measurement techniques, demonstrated similar deviations from radiographic standards, and did not appear to be influenced by the person performing the measurements or the girth of the extremit

    Methicillin-resistant Staphylococcus aureus Colonization in Veterinary Personnel

    Get PDF
    TOC Summary: Prevalence of colonization was 6.5%, and employment within a large-animal practice was a significant risk factor

    Millennial-scale vegetation changes in the tropical Andes using ecological grouping and ordination methods

    Get PDF
    We compare eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the last 30ĝ€ 000 years, with particular emphasis on the Pleistocene to Holocene transition. We explore ecological grouping and downcore ordination results as two approaches for extracting environmental variability from pollen records. We also use the records of aquatic and shoreline vegetation as markers for lake level fluctuations and moisture availability. Our analysis focuses on the signature of millennial-scale climate variability in the tropical Andes, in particular Heinrich stadials (HS) and Greenland interstadials (GI). The pollen records show an overall warming trend during the Pleistocene-Holocene transition, but the onset of post-glacial warming differs in timing among records. We identify rapid responses of the tropical vegetation to millennial-scale climate variability. The signatures of HS and the Younger Dryas are generally recorded as downslope upper forest line (UFL) migrations in our transect, and are likely linked to air temperature cooling. The GI1 signal is overall comparable between northern and southern records and indicates upslope UFL migrations and warming in the tropical Andes. Our marker for lake level changes indicated a north-To-south difference that could be related to moisture availability. The air temperature signature recorded by the Andean vegetation was consistent with millennial-scale cryosphere and sea surface temperature changes but suggests a potential difference between the magnitude of temperature change in the ocean and the atmosphere. We also show that arboreal pollen percentage (AP %) and detrended correspondence analysis (DCA) scores are two complementary approaches to extract environmental variability from pollen records

    g9/2g_{9/2} neutron strength in the N=29N=29 isotones and the 52^{52}Cr(d,pd,p)53^{53}Cr reaction

    Full text link
    We performed a measurement of the 52^{52}Cr(d,p)53(d,p)^{53}Cr reaction at 16 MeV using the Florida State University Super-Enge Split-Pole Spectrograph (SE-SPS) and observed 26 states. While all of the states observed here had been seen in previous (d,p)(d,p) experiments, we changed five LL assignments from those reported previously and determined LL values for nine states that had not had such assignments made previously. The g9/2g_{9/2} neutron strength observed in 53^{53}Cr in the present work and in the N=29N=29 isotones 49^{49}Ca, 51^{51}Ti, and 55^{55}Fe via (d,p)(d,p) reactions is much smaller than the sum rule for this strength. Most of the observed L=4L=4 strength in these nuclei is located in states near 4 MeV excitation energy. The remaining g9/2g_{9/2} strength may be located in the continuum or may be fragmented among many bound states. A covariant density functional theory calculation provides support for the hypothesis that the g9/2g_{9/2} neutron orbit is unbound in 53^{53}Cr. The (α,3\alpha,^3He) reaction may provide a more sensitive probe for the missing g9/2g_{9/2} neutron strength. In addition, particle-γ\gamma coincidence experiments may help resolve some remaining questions in this nucleus.Comment: 15 pages, 5 figures. arXiv admin note: text overlap with arXiv:2212.0438
    • …
    corecore