More than one way to see it: Individual heuristics in avian visual computation

Comparative pattern learning experiments investigate how different species find regularities in sensory input, providing insights into cognitive processing in humans and other animals. Past research has focused either on one species’ ability to process pattern classes or different species’ performance in recognizing the same pattern, with little attention to individual and species-specific heuristics and decision strategies. We trained and tested two bird species, pigeons (Columba livia) and kea (Nestor notabilis, a parrot species), on visual patterns using touch-screen technology. Patterns were composed of several abstract elements and had varying degrees of structural complexity. We developed a model selection paradigm, based on regular expressions, that allowed us to reconstruct the specific decision strategies and cognitive heuristics adopted by a given individual in our task. Individual birds showed considerable differences in the number, type and heterogeneity of heuristic strategies adopted. Birds’ choices also exhibited consistent species-level differences. Kea adopted effective heuristic strategies, based on matching learned bigrams to stimulus edges. Individual pigeons, in contrast, adopted an idiosyncratic mix of strategies that included local transition probabilities and global string similarity. Although performance was above chance and quite high for kea, no individual of either species provided clear evidence of learning exactly the rule used to generate the training stimuli. Our results show that similar behavioral outcomes can be achieved using dramatically different strategies and highlight the dangers of combining multiple individuals in a group analysis. These findings, and our general approach, have implications for the design of future pattern learning experiments, and the interpretation of comparative cognition research more generally

Online forest biology and tree identification graduate class for public school educators

As a result of certification and accreditation standards, public school teachers are often required to take graduate education courses. However, it is often difficult for these teachers/students to take courses in residence at campuses. Further, there is often a shortage of specialized courses in their area of teaching. There is also a demand for natural-resource-based classes since, in Virginia, many of the standards of learning can be effectively taught using examples from forests. In response to the above issues, we developed an entirely online graduate course that covered forest biology, management, and tree identification. In the summer of 2001, 24 students successfully completed the course. Students were required to learn to identify 80 trees and shrubs in nine separate groups. They were also taught tree growth and structure, reproduction, carbon uptake, water relations, growth regulators, cold hardiness and dormancy, soils and site productivity, and silviculture. The course content was delivered on three CD-ROMS and administration occurred through a Web site. Nine cumulative tree ID quizzes were given online as well as two comprehensive exams covering the tree biology topics. We will present the basic structure of the course, class administration, share insights and student feedback

Evaluation of an Adaptive Suspension Vehicle

The Adaptive Suspension Vehicle, a proof-of-concept, six-legged robotic walking machine, was subject to a series of field trials to evaluate the maneuverability and trafficability characteristics of walking machines. Maneuverability trials were structured to test performance as a carrier for frame-mounted feller-buncher heads in both thinning and clearcutting applications. The trafficability trials focused on the type and extent of soil disturbance, especially changes in soil bulk density, mechanical resistance, macro- and micro-porosity, the machine was found to impact the soil very differently than wheeled or tracked equipment. Direct comparisons of soil parameters were limited because of time and budget restrictions but seem to indicate that the legged locomotion offered distinct production and soil disturbance advantages, especially on steep slopes and in wetlands

Turning product design into public service

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Statement of responsibility on t.p. reads: Laura E. Aust, Zachary W. Rose, Ariadne G. Smith, Amrita Saigal. Each student submitted a title page and vita. Cataloged from PDF version of thesis.Includes bibliographical references (p. 87-89 ([i.e. p. [99]-[101])).Every mechanical engineering student at MIT takes the same courses: 2.009 being one of them. In our capstone product design course at MIT, most students glean an incredible amount from their teams, mentors, and projects, then focus their efforts on slightly more pressing issues, such as graduating and finding jobs and grad school. But what if the project you found was bigger than just a course, and had the potential of improving the lives of those less fortunate than you? The Komera project creates affordable sanitary protection for women in developing countries from the locally available and all-natural fiber from banana plants. In doing so, the initiative not only empowers girls by allowing them to attend school during their periods, but also creates employment and income within their communities. Our first initial iterations of the machine to fabricate pads were created in 2.009. Previous mechanical solutions to this problem are inefficient and labor-intensive. With our prototype, we seek to reduce the labor involved and increase pad output by twofold. However, we didn't want out work to stop there. Over the course of the semester, we continued to expand the Komera project twofold: by working on the mechanical design of the product and by expanding our scope to transform the product into a public service initiative. This thesis discusses the trials and tribulations of both directions. We explore the differences and challenges in designing for the developing world within a 1 st-world product design context - paying attention to manufacturing, materials, cost, and usability. We also offer a guide through the creation of an initiative: how we took a product and turned it into an IDEAS-winning public service project. It has been an incredibly rewarding experience for us, and we hope that we can inspire others to work on international development products as well.by Laura E. Aust ... [et al.].S.B

The magnetic interactions in spin-glasslike Ge/1-x-y/Sn/x/Mn/y/Te diluted magnetic semiconductor

We investigated the nature of the magnetic phase transition in the Ge/1-x-y/Sn/x/Mn/y/Te mixed crystals with chemical composition changing in the range of 0.083 < x < 0.142 and 0.012 < y < 0.119. The DC magnetization measurements performed in the magnetic field up to 90 kOe and temperature range 2-200 K showed that the magnetic ordering at temperatures below T = 50 K exhibits features characteristic for both spin-glass and ferromagnetic phases. The modified Sherrington - Southern model was applied to explain the observed transition temperatures. The calculations showed that the spin-glass state is preferred in the range of the experimental carrier concentrations and Mn content. The value of the Mn hole exchange integral was estimated to be J/pd/ = 0.45+/-0.05 eV. The experimental magnetization vs temperature curves were reproduced satisfactory using the non-interacting spin-wave theory with the exchange constant J/pd/ values consistent with those calculated using modified Sherrington - Southern model. The magnetization vs magnetic field curves showed nonsaturating behavior at magnetic fields B < 90 kOe indicating the presence of strong magnetic frustration in the system. The experimental results were reproduced theoretically with good accuracy using the molecular field approximation-based model of a disordered ferromagnet with long-range RKKY interaction.Comment: 9 pages, 6 figure

Reproductive non-seasonality in rhinoceroses: A review of the in-situ literature and birth records of ex-situ institutions

Mammals whose breeding activity is triggered by seasonal photoperiodic cues typically maintain seasonal reproduction in zoos, with births accumulating to various degrees in spring. For zoo-kept rhinoceroses, accumulation of births in autumn has been suggested, which would make this group unusual. We compare birthing (and hence conception) patterns of free-ranging rhinoceros populations from the scientific literature with those of the global zoo populations based on birth data available from Species360, to facilitate deductions on the cues that trigger rhinoceros reproduction. The patterns do not indicate a photoperiodic element in rhinoceros reproduction but suggest suppression of conception in free-ranging populations at times of resource scarcity. This is not evident in zoos. However, a slight accumulation of autumn births, due to a slight reduction in births in spring, is visible in the zoo populations. Given rhinoceros gestation periods, this is linked to reduced conceptions in November–December. The most parsimonious interpretation is management-related, as has been suggested (Roth 2006, Int. Zoo Yb. 40(1): 130–143): not all facilities are prepared to allow mating at times when outdoor husbandry is reduced due to weather restrictions. Given the long interbirth intervals of rhinoceroses, missed conception opportunities of 1–2 months are unlikely to affect population demographics. Nevertheless, detailed recording of approaches to facilitate mating during winter months by those zoos that achieve this may increase the general skill of rhinoceros management

Preoperative prism adaptation test in normosensoric strabismus

In 19 patients with normosensoric esotropia, the squint angles measured with the alternate cover test were compared with those after prolonged prismatic correction of the squint angle and with those after prolonged occlusion of one eye. All patients showed an increase of the squint angle after prism adaptation. The angle was generally smaller after diagnostic occlusion of one eye than after prism adaptation. We assume that the increase in the squint angle after prism adaptation is caused by an anomalous sensorial relationship between the two eyes that was not detected with the usual psychophysical tests. Surgery tailored to the squint angle after prism adaptation seems advisable in patients with normosensoric esotropia