Cryomorphological topographies in the study of ice caves

Producción CientíficaThe current interest in ice caves requires that their varied manifestations be known as accurately as possible in view of their responses to a global change and also to their great potential as paleoenvironmental witnesses. This phenomenon has been known about for a long time but is still scarcely studied from the point of view of its cryological values and the evolution and distribution of many of their morphologies. For this, the development of cryomorphological topographies from traditional techniques to geodetic surveys with different tools, including terrestrial laser scanning, is one of the most current ways to characterize and quantify this type of cryospheric phenomena. It represents a new kind of periglacial cartography whose use is feasible in spite of the difficulties these environments present.Ministerio de Economía, Industria y Competitividad (project CGL2015-68144-R

Hunters like skewness, not risk: evidence of gambling behaviors in the Alaska hunting permit lottery

Thesis (M.S.) University of Alaska Fairbanks, 2018In Alaska, hunting permits are distributed by traditional lottery. The absence of a preference point system means that applicants have little invested in their applications, and there are a variety of fallback hunting opportunities. Not unlike a jackpot-style state lottery, the cost to play is low relative to the potential prize winnings. These factors may cause risk-averse or risk-neutral individuals to exhibit a preference for positive skewness in their bets. Analysis in this paper is focused on four prevalent game species: moose, dall sheep, mountain goat, and bison. Pooled Ordinary Least Squares regression models were constructed to predict permit application levels as a function of various hunt characteristics, qualities, and restrictions. Permit descriptions are provided to applicants in a published document called the drawing supplement, which is the primary source of data for this study. Additional hunter-reported data is obtained from the Alaska Department of Fish and Game website. A comparison of calculated permit values and private ranch hunting opportunities validates many of the observations drawn from the models. Permit values are also used to fit a cubic model of bettor utility. Even when awarded prizes are not monetary, applicants exhibit a preference for positive skewness and aversion from risk that is typically associated with gambling

Post-Acquisition Small-Animal Respiratory Gated Imaging Using Micro Cone-Beam CT

On many occasions, it is desirable to image lungs in vivo to perform a pulmonary physiology study. Since the lungs are moving, gating with respect to the ventilatory phase has to be performed in order to minimize motion artifacts. Gating can be done in real time, similar to cardiac imaging in clinical applications, however, there are technical problems that have lead us to investigate different approaches. The problems include breath-to-breath inconsistencies in tidal volume, which makes the precise detection of ventilatory phase difficult, and the relatively high ventilation rates seen in small animals (rats and mice have ventilation rates in the range of a hundred cycles per minute), which challenges the capture rate of many imaging systems (this is particularly true of our system which utilizes cone-beam geometry and a 2 dimensional detector). Instead of pre-capture ventilation gating we implemented a method of post-acquisition gating. We acquire a sequence of projections images at 30 frames per second for each of 360 viewing angles. During each capture sequence the rat undergoes multiple ventilation cycles. Using the sequence of projection images, an automated region of interest algorithm, based on integrated grayscale intensity, tracts the ventilatory phase of the lungs. In the processing of an image sequence, multiple projection images are identified at a particular phase and averaged to improve the signal-to-ratio. The resulting averaged projection images are input to a Feldkamp cone-beam algorithm reconstruction algorithm in order to obtain isotropic image volumes. Minimal motion artifact data sets improve qualitative and quantitative analysis techniques useful in physiologic studies of pulmonary structure and function

Estimating snow cover from publicly available images

In this paper we study the problem of estimating snow cover in mountainous regions, that is, the spatial extent of the earth surface covered by snow. We argue that publicly available visual content, in the form of user generated photographs and image feeds from outdoor webcams, can both be leveraged as additional measurement sources, complementing existing ground, satellite and airborne sensor data. To this end, we describe two content acquisition and processing pipelines that are tailored to such sources, addressing the specific challenges posed by each of them, e.g., identifying the mountain peaks, filtering out images taken in bad weather conditions, handling varying illumination conditions. The final outcome is summarized in a snow cover index, which indicates for a specific mountain and day of the year, the fraction of visible area covered by snow, possibly at different elevations. We created a manually labelled dataset to assess the accuracy of the image snow covered area estimation, achieving 90.0% precision at 91.1% recall. In addition, we show that seasonal trends related to air temperature are captured by the snow cover index.Comment: submitted to IEEE Transactions on Multimedi

The Uniformly Most Powerful Invariant Test for the Shoulder Condition in Point Transect Sampling

Estimating population abundance is of primary interest in wildlife population studies. Point transect sampling is a well established methodology for this purpose. The usual approach for estimating the density or the size of the population of interest is to assume a particular model for the detection function (the conditional probability of detecting an animal given that it is at a given distance from the observer). The two most popular models for this function are the half-normal model and the negative exponential model. However, it appears that the estimates are extremely sensitive to the shape of the detection function, particularly to the so-called shoulder condition, which ensures that an animal is almost certain to be detected if it is at a small distance from the observer. The half-normal model satisfies this condition whereas the negative exponential does not. Therefore, testing whether such a hypothesis is consistent with the data at hand should be a primary concern in every study concerning the estimation of animal abundance. In this paper we propose a test for this purpose. This is the uniformly most powerful test in the class of the scale invariant tests. The asymptotic distribution of the test statistic is calculated by utilising both the half-normal and negative exponential model while the critical values and the power are tabulated via Monte Carlo simulations for small samples. Finally, the procedure is applied to two datasets of chipping sparrows collected at the Rocky Mountain Bird Observatory, Colorado..Point Transect Sampling, Shoulder Condition, Uniformly Most Powerful Invariant Test, Asymptotic Critical Values, Monte Carlo Critical Values

Authentic student inquiry: the mismatch between the intended curriculum and the student-experienced curriculum

As a means of achieving scientific literacy goals in society, the last two decades have witnessed international science curriculum redevelopment that increasingly advocates a 'new look' inquiry-based approach to learning. This paper reports on the nature of the student-experienced curriculum where secondary school students are learning under a national curriculum that is intent on promoting students' knowledge and capabilities in authentic scientific inquiry, that is, inquiry that properly reflects that practiced by members of scientific communities. Using a multiple case study approach, this study found that layers of curriculum interpretation from several 'sites of influence' both outside and inside of the schools have a strong bearing on the curriculum enacted by teachers and actually experienced by the students, and runs counter to the aims of the national curriculum policy. Over-emphasis on fair testing limits students' exposure to the full range of methods that scientists use in practice, and standards-based assessment using planning templates, exemplar assessment schedules and restricted opportunities for full investigations in different contexts tends to reduce student learning about experimental design to an exercise in 'following the rules'. These classroom realities have implications for students' understanding of the nature of authentic scientific inquiry and support claims that school science is still far removed from real science