Persistence pays off: Sir Charles Oatley and the scanning electron microscope

Shortly after World War II, Sir Charles Oatley initiated research at the Cambridge University engineering laboratories on what has evolved into the modern scanning electron microscope. While much of the research was actually conducted by research students under Oatley's supervision, he continually provided ideas, resources, and encouragement. He then was instrumental in having this instrument commercialized. His students often continued in the field for some time, making contributions both to the instrument and to its applications that led to improved performance and wider acceptance. This article attempts to capture some of the accomplishments of Sir Charles Oatley as seen by those who worked closely with him. The author believes that Sir Charles deserves the title: "Father of the Modern Scanning Electron Microscope.

The evolution of comet orbits

The origin of comets and the evolution of their orbits are discussed. Factors considered include: the law of survival of comets against ejection on hyperbolic orbits; short-period comets are not created by single close encounters of near-parabolic comets with Jupiter; observable long-period comets do not evolve into observable short-period comets; unobservable long-period comets with perihelia near Jupiter can evolve into observable short-period comets; long-period comets cannot have been formed or created within the planetary region of the solar system (excluding the effects of stellar perturbations); it is possible that some of the short-period comets could have been formed inside the orbit of Neptune; circularly-restricted three-body problem, and its associated Jacobi integral, are not valid approximations to use in studying origin and evolution of comets

Empathy Activators: Strategies for Developing Empathy in Service-Learning Students

This poster presentation explores the link between service-learning and the development of student empathy. It will share the initial research results of a pilot study on student empathy, service-learning, and key ingredients for cultivating empathy. It also offers instructors concrete ideas for teaching tools that activate student empathy

A one-dimensional Fermi accelerator model with moving wall described by a nonlinear van der Pol oscillator

A modification of the one-dimensional Fermi accelerator model is considered in this work. The dynamics of a classical particle of mass $m$, confined to bounce elastically between two rigid walls where one is described by a non-linear van der Pol type oscillator while the other one is fixed, working as a re-injection mechanism of the particle for a next collision, is carefully made by the use of a two-dimensional non-linear mapping. Two cases are considered: (i) the situation where the particle has mass negligible as compared to the mass of the moving wall and does not affect the motion of it; (ii) the case where collisions of the particle does affect the movement of the moving wall. For case (i) the phase space is of mixed type leading us to observe a scaling of the average velocity as a function of the parameter ($\c{hi}$) controlling the non-linearity of the moving wall. For large $\c{hi}$, a diffusion on the velocity is observed leading us to conclude that Fermi acceleration is taking place. On the other hand for case (ii), the motion of the moving wall is affected by collisions with the particle. However due to the properties of the van der Pol oscillation, the moving wall relaxes again to a limit cycle. Such kind of motion absorbs part of the energy of the particle leading to a suppression of the unlimited energy gain as observed in case (i). The phase space shows a set of attractors of different periods whose basin of attraction has a complicate organization

PLPT 496/892: Disease Dynamics & Evolution—A Peer Review of Teaching Project Benchmark Portfolio

This benchmark course portfolio was developed as a component of the University of Nebraska Peer Review of Teaching. The course selected for this portfolio was a new course developed and taught as an Independent Study PLPT 496/892. The working title for the course was Disease Dynamics and Evolution. This course was designed to cover core concepts of disease ecology and pathogen emergence/evolution. Concepts were organism-agnostic and important for understanding infectious diseases of humans, animals, and plants. The course format was lecture-based and inquiry driven, using primary literature as case studies. The goal of this course was to use interesting and intriguing case studies of infectious diseases to develop critical thinking as scientists. The course was designed to be appropriate for a wide variety of biology students, with interests in ecology, environmental biology, animal, plant, and human biology to microbiology, pre-vet and pre-med. A pre-requisite for undergraduates was BIOS 312 or permission of instructor. It is expected the course will be offered in the spring semester of even-numbered years

Upper Canopy Collection and Identification of Grapevines (\u3ci\u3eVitis\u3c/i\u3e) from Selected Forests in the Southeastern United States

Woody grapevines (Vitis spp.) are common in the deciduous forests of the southeastern United States. Their growth habit makes leaf collection challenging and polymorphic leaves make identification of species difficult. Mature grapevines can grow up to 48 cm in diameter at breast height and reach the upper canopy of trees more than 35 m in height. Leaf morphology is the most readily available character used for species identification. However, most mature grapevines do not produce leaves below the upper canopy and if they do, these leaves are morphologically indistinguishable from other species. In order to sample leaves from mature grapevines, the doubled rope climbing method was used to access the canopy in Great Smoky Mountains National Park in Tennessee, Daniel Boone National Forest and Berea College Forest in Kentucky, and Ha Ha Tonka State Park in Missouri. Leaf voucher specimens were collected from the upper canopy and used to create a modified key to species for those regions. The purposes of this paper are to report a new method for collecting grapevine leaf vouchers from the upper canopy of trees, to present a modified key used for identifying dried leaf vouchers of Vitis species, and to present a discussion of the possible utility of this research for future studies

PLPT 496/892: Disease Dynamics & Evolution—A Peer Review of Teaching Project Benchmark Portfolio

This benchmark course portfolio was developed as a component of the University of Nebraska Peer Review of Teaching. The course selected for this portfolio was a new course developed and taught as an Independent Study PLPT 496/892. The working title for the course was Disease Dynamics and Evolution. This course was designed to cover core concepts of disease ecology and pathogen emergence/evolution. Concepts were organism-agnostic and important for understanding infectious diseases of humans, animals, and plants. The course format was lecture-based and inquiry driven, using primary literature as case studies. The goal of this course was to use interesting and intriguing case studies of infectious diseases to develop critical thinking as scientists. The course was designed to be appropriate for a wide variety of biology students, with interests in ecology, environmental biology, animal, plant, and human biology to microbiology, pre-vet and pre-med. A pre-requisite for undergraduates was BIOS 312 or permission of instructor. It is expected the course will be offered in the spring semester of even-numbered years

Technology and human progress: the information revolution

LectureThe world has entered the Information Age. We can look forward to even more dramatic changes in the future than those we have witnessed in the past. These changes are challenging individuals, institutions, and nations. Even though information transmission, processing, and utilization has increased by orders of magnitude, humans are the beneficiaries of this information. Our ability to absorb and understand information has not increased by orders of magnitude. How we learn to cope with the wealth of information available to us will determine whether we ultimately benefit from the information revolution as individuals and as a nation. The future will require us to be adaptable, to continue to learn, and to continue to explore the frontiers of science, technology, and their application. Let us hope that the people of our shrinking planet Earth will find a common goal of individual and global survival, and will utilize technology for the benefits that it can bestow upon the human race

Upper Canopy Collection and Identification of Grapevines (\u3ci\u3eVitis\u3c/i\u3e) from Selected Forests in the Southeastern United States

Woody grapevines (Vitis spp.) are common in the deciduous forests of the southeastern United States. Their growth habit makes leaf collection challenging and polymorphic leaves make identification of species difficult. Mature grapevines can grow up to 48 cm in diameter at breast height and reach the upper canopy of trees more than 35 m in height. Leaf morphology is the most readily available character used for species identification. However, most mature grapevines do not produce leaves below the upper canopy and if they do, these leaves are morphologically indistinguishable from other species. In order to sample leaves from mature grapevines, the doubled rope climbing method was used to access the canopy in Great Smoky Mountains National Park in Tennessee, Daniel Boone National Forest and Berea College Forest in Kentucky, and Ha Ha Tonka State Park in Missouri. Leaf voucher specimens were collected from the upper canopy and used to create a modified key to species for those regions. The purposes of this paper are to report a new method for collecting grapevine leaf vouchers from the upper canopy of trees, to present a modified key used for identifying dried leaf vouchers of Vitis species, and to present a discussion of the possible utility of this research for future studies