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Assortative mixing in eastern spadefoot (Scaphiopus holbrookii) spatial networks is driven by landscape features
Get PDFBiotic and abiotic factors drive assortative mixing (preference for or sorting with individuals with similar characteristics) in animal populations on a landscape, with implications for dispersal, population structuring, and other ecological and evolutionary processes. However, patterns and generative mechanisms of assortative mixing are overlooked in amphibians outside of specific life history events such as reproduction. The aims of this project were to determine whether there is assortative mixing by size and life history category in eastern spadefoots (Scaphiopus holbrookii), whether these patterns are preserved across time and spatial scale, and quantify the nature and relative role of various habitat and soil features in explaining observed patterns in spatial organization of individuals. We conducted field surveys in southeastern Virginia, USA, in 2016 and 2017 during nonbreeding periods to create spatial networks of S. holbrookii. We quantified spatial assortativity by size and life history stage and evaluated the roles of multiple landscape features in explaining spatial organization of S. holbrookii. We found that S. holbrookii sorted spatially by size and sex outside of breeding periods, with juveniles and adults less likely to sort with each other. Within each life history stage, S. holbrookii sorted by size. These patterns were similar across time and spatial scale. Soil and habitat types had no effect on assortativity. Instead, the distance to nearest breeding pool, wetland, and meadow were related to life history stage assortativity, as well as size assortativity in males and subadults. Adult males and females displayed affinity for breeding pools and meadows and avoidance of other types of wetlands, while subadults and nonbreeding adults showed opposite patterns compared with breeding adults. Our results indicate that (1) previously established guidelines for the minimum size of buffer zones to protect wetland-breeding amphibians may be inadequate, (2) nonbreeding wetlands may be important core habitat for subadults, and (3) the upland spatial organization of amphibians may be used to predict locations of undetected breeding pools
Subsidence in Coastal Cities Throughout the World Observed by InSAR
Get PDFWe measured subsidence rates in 99 coastal cities around the world between 2015 and 2020 using the PS Interferometric Synthetic Aperture Radar method and Sentinel-1 data. In most cities, part of the land is subsiding faster than sea level is rising. If subsidence continues at present rates, these cities will be challenged by flooding much sooner than projected by sea level rise models. The most rapid subsidence is occurring in South, Southeast, and East Asia. However, rapid subsidence is also happening in North America, Europe, Africa, and Australia. Human activity—primarily groundwater extraction—is likely the main cause of this subsidence. Expanded monitoring and policy interventions are required to reduce subsidence rates and minimize their consequences
A Call to Action for Clinical Exercise Physiologists: Why You Need Your National Provider Identifier and How to Get One for Free
No full textInterfacial Effects of the Photophysics of Rhodamine 6G Ultra-Thin Films on a Poly(methylmethacrylate) Surface
No full textThe absorbance, excitation, and emission spectra of ultra-thin films of rhodamine 6G (Rh6G) spin-cast on poly(methylmethacrylate) (PMMA)-coated glass slides are examined as a function of both PMMA and Rh6G thickness. The thickness of PMMA has a little effect on the absorption or emission properties of Rh6G. At low surface coverage, the spectral properties of Rh6G are dominated by isolated molecules. As the Rh6G thickness increases, there is no evidence for exciton formation. Instead, the Rh6G molecules aggregate, which is responsible for the observed absorption and emission spectra. The aggregates significantly quench the emission so that the maximum emission intensity is found just below a monolayer surface coverage. The lack of exciton formation, which is unexpected, is attributed to the surface morphology of PMMA, which has a periodic surface structure
Determining the threshold displacement energy of magnesium using molecular dynamics simulations
No full textDespite its potential use as a lightweight material, the effects of irradiation on magnesium (Mg) remain poorly understood. Specifically, the threshold displacement energy (TDE), which corresponds to the minimum energy required to displace an atom from the lattice position has not been explored so far. Here, using molecular simulations, we estimate the TDE of an Mg single crystal. We observe that the TDE is not significantly affected by the location of an atom in the lattice and the incident direction of energy or collision. We also demonstrate the formation of local defects, which are instantly annealed. Interestingly, the annealing process is facilitated by the temporary displacement of atoms from their lattice position into the interstitials, which in turn results in the creation of at least one stable Frenkel pair defect. Overall, this study provides insights into the response of Mg crystal to radiation, which is crucial for development of Mg-based structures for applications in aerospace and nuclear industries
Implementation and Feedback Control Tuning of an Analog Izhikevich Neuron Circuit
No full textAnalog circuits have proven to be a reliable medium for neuromorphic architectures in silicon, capable of emulating parts of the brain\u27s computational processes. Information in the brain is shared between neurons in the form of spikes, where a neuron\u27s soma emits a voltage signal after integrating multiple synaptic input currents. To preserve the quality of this information in a rate-based protocol, it is important that a post-synaptic neuron is able to adapt its firing rate to some desired or expected rate, especially in a noisy environment. This paper presents an analog Izhikevich neuron circuit and a proof-of-concept tuning algorithm that adjusts the neuron\u27s spike rate using proportional feedback control. The neuron circuit is implemented using discrete surface-mount components on a custom printed circuit board, and its output spike pattern is modified by adjusting one of the neuron\u27s four voltage parameters. Adjusting the voltage parameters gives a neuromorphic system designer the ability to calibrate these silicon neurons in the presence of noise or component imperfections, ensuring a baseline configuration where all neurons exhibit the same, expected spike response given the same input
The Importance of Parent-Teacher Communication and Collaboration and How to Enhance Them for Various Types of Families
Get PDFAn educator is defined as someone who provides instruction to others. What this definition does not include is how the role of a teacher or educator goes far beyond merely providing instructions and teaching others. In order to be effective, teachers must learn how to adequately communicate and collaborate with their students, other education professionals, and families. Especially in the education field, teachers must learn how to communicate and collaborate with each student’s family to help create positive, productive, and beneficial professional relationships.
Communication should be ongoing and should be carried out in a manner that works for both the parents and the teacher. Therefore, for a teacher to be able to communicate and collaborate effectively with others, they must first understand that there is not one form of communication that works best with every individual or family. Just as each student learns differently and is most successful when instruction can be differentiated to their learning style, every family is unique and has distinct values, a distinct structure, and distinct needs. Some families may need more frequent communication with their children’s educators than other families do, and some may need additional resources - such as technology access or translated materials - to communicate fully.
As a future educator, I wanted to learn more about the importance of communication and collaboration with families in an educational setting and how I can best utilize them in my teaching. To help meet these goals, I researched best practices in communication and collaboration for different types of families, specifically considering families who have a child with disabilities; families who may speak English as a second language; and families who are living in low-income areas
Encouraging Adolescents to be Self-Directed Learners: Influences of Classroom Motivation on Student Outcomes
Get PDFTeaching American adolescents in public schools presents a unique challenge: how to foster an instructional environment that simultaneously encourages intrinsic desires for lifelong learning, allows for the development of self-determination and autonomy, and teaches students appropriate academic skills. It was hypothesized that relying mainly on extrinsic motivations would be associated with more problematic outcomes for students while relying mainly on intrinsic motivations would be associated with more desirable outcomes. Additionally, it was hypothesized that schools organized around different educational philosophies would favor the use of different motivational strategies. A literature review was conducted that included a review of theories of learning pertinent to student motivation with specific emphases on ethical perspectives, educational philosophy perspectives, and motivation research perspectives. Results yielded conclusions around the value of intrinsic motivations and the effectiveness of a balance between intrinsic and extrinsic motivations in classrooms. Implications for this work suggest that teachers individualize and adjust current curriculums and teaching practices based on the characteristics and situations of the individual students and classrooms as a whole. Additionally, at the whole school level, periodic reviews of motivational practices should be conducted to assess the alignment of practices with student needs, goals, and outcomes
