Symmetry properties of vibrational modes in graphene nanoribbons

We present symmetry properties of the lattice vibrations of graphene nanoribbons with pure armchair (AGNR) and zigzag edges (ZGNR). In non-symmorphic nanoribbons the phonon modes at the edge of the Brillouin zone are twofold degenerate, whereas the phonon modes in symmorphic nanoribbons are non-degenerate. We identified the Raman-active and infrared-active modes. We predict 3N and 3(N+1) Raman-active modes for N-ZGNRs and N-AGNRs, respectively (N is the number of dimers per unit cell). These modes can be used for the experimental characterization of graphene nanoribbons. Calculations based on density functional theory suggest that the frequency splitting of the LO and TO in AGNRs (corresponding to the E2g mode in graphene) exhibits characteristic width and family dependence. Further, all graphene nanoribbons have a Raman-active breathing-like mode, the frequency of which is inversely proportional to the nanoribbon width and thus might be used for experimental determination of the width of graphene nanoribbons.Comment: 10 pages, 5 figure

Capturing Regular Human Activity through a Learning Context Memory

A learning context memory consisting of two main parts is presented. The first part performs lossy data compression, keeping the amount of stored data at a minimum by combining similar context attributes — the compression rate for the presented GPS data is 150:1 on average. The resulting data is stored in an appropriate data structure highlighting the level of compression. Elements with a high level of compression are used in the second part to form the start and end points of episodes capturing common activity consisting of consecutive events. The context memory is used to investigate how little context data can be stored containing still enough information to capture regular human activity

Navigation systems for approach and landing of VTOL aircraft

The formulation and implementation of navigation systems used for research investigations in the V/STOLAND avionics system are described. The navigation systems prove position and velocity in a cartestian reference frame aligned with the runway. They use filtering techniques to combine the raw position data from navaids (e.g., TACAN, MLS) with data from onboard inertial sensors. The filtering techniques which use both complementary and Kalman filters, are described. The software for the navigation systems is also described

Self-energy values for P states in hydrogen and low-Z hydrogenlike ions

We describe a nonperturbative (in Zalpha) numerical evaluation of the one-photon electron self energy for 3P_{1/2}, 3P_{3/2}, 4P_{1/2} and 4P_{3/2} states in hydrogenlike atomic systems with charge numbers Z=1 to 5. The numerical results are found to be in agreement with known terms in the expansion of the self energy in powers of Zalpha and lead to improved theoretical predictions for the self-energy shift of these states.Comment: 3 pages, RevTe

Long-term follow-up of 22 psoriatic patients treated with ixekizumab after failure of secukinumab

Switching of biologic agents in treatment of plaque psoriasis is a common strategy. Only a few studies are available on switching between IL17A-blockers. In a retrospective study, we identified 22 psoriasis patients who, after failing secukinumab as a first IL17A-blocker received ixekizumab with an observation period of at least 24 weeks. At last observation 10/22 patients had a good response (PASI75 or PASI<3) using ixekizumab therapy. None of five patients with primary non-response to secukinumab reached a good, durable response to ixekizumab. In conclusion, ixekizumab appears to be a therapeutic option as a second IL17A-blocker in psoriasis patients who did not show a primary non-response to secukinumab

Lamb Shift of 3P and 4P states and the determination of α\alpha

The fine structure interval of P states in hydrogenlike systems can be determined theoretically with high precision, because the energy levels of P states are only slightly influenced by the structure of the nucleus. Therefore a measurement of the fine structure may serve as an excellent test of QED in bound systems or alternatively as a means of determining the fine structure constant $\alpha$ with very high precision. In this paper an improved analytic calculation of higher-order binding corrections to the one-loop self energy of 3P and 4P states in hydrogen-like systems with low nuclear charge number $Z$ is presented. A comparison of the analytic results to the extrapolated numerical data for high $Z$ ions serves as an independent test of the analytic evaluation. New theoretical values for the Lamb shift of the P states and for the fine structure splittings are given.Comment: 33 pages, LaTeX, 4 tables, 4 figure

Understanding Generation Z Students to Promote a Contemporary Learning Environment

University faculty predominantly represent the Baby Boomer and Baby Buster (Gen X) Generations, but, university students are largely iYs Millenials and Generation Z Digital Natives. These groups have been characterized both positively and negatively in the popular press. A fresh understanding of the newer generations can help instructors better meet current students’ educational needs. This article shares brief generational profiles based on recent research and then presents questions and recommendations for improving course assignments and their effectiveness. Ways of communicating about assignments and their benefits are also shared. The goal is to equip college-level instructors with ways to relate to and support the newest generation of learners

A tale of two cervids: habitat selection and spatial ecology of Roosevelt and tule elk in California

California’s Roosevelt (Cervus canadensis rooseveltii) and tule elk (C. c. nannodes) populations have experienced a remarkable recovery after over-hunting and habitat loss nearly extirpated them from the state. Greater clarity of Roosevelt and tule elk habitat selection patterns would help managers continue to effectively support the recovery of these two iconic subspecies. As the manner in which elk populations balance their competing resource needs is unique to each population (Skovlin et al. 2002), I have examined Roosevelt and tule elk habitat selection patterns in separate analyses and present these results in independent chapters. In both cases, I examine the role behavior can play in influencing habitat selection and fitness. Habitat selection models rely on a number of assumptions, which have proven difficult to test, particularly in regards to how behavior relates to perceived habitat suitability and resource availability. In this thesis, I address some of these assumptions by accounting for variation in elk behavior and changing resource conditions. My results demonstrate the effect of behavioral and seasonal resource variation on habitat suitability predictions and its importance for consideration in population management decisions. Chapter 1 Abstract: Habitat selection models often assume individuals within a population behave identically, which is problematic as behavior can vary non-randomly due to differences in how individuals perceive and respond to predation risk. I used GPS location data and a measure of human-tolerance (on a scale of “bold” to “shy”) to examine habitat selection patterns and make predictions about habitat suitability and potential abundance of Roosevelt elk in northwestern California, USA. Overall, elk selected for areas of open land cover types, in close proximity to forest edge, further from roads, and with gentle terrain. Shy elk remained closer to forest edge and further from roads compared to bold elk. Predicted elk habitat differed between bold and shy elk, but potential abundance estimates were relatively consistent at around 13,000-14,000 elk in the study area. Management decisions should be made at the level of individual elk groups when feasible, as decisions that affect an elk group’s tolerance of human disturbance will impact the availability and composition of suitable habitat, and ultimately may affect potential abundance. Chapter 2 Abstract: Climate change is expected to affect arid-system ungulate populations by altering the availability of critical resources, such as forage and water sources, and by increasing the frequency and severity of drought. The habitat selection patterns of the tule elk, a subspecies endemic to the Mediterranean climate regions of California, may provide insight into the behavioral adaptations which will allow affected ungulate populations to remain in their current geographic ranges. I used location data from GPS-collared tule elk to model their response to different environmental covariates including water sources, forage dynamics, human disturbance, and drought, across the wet and dry seasons. I found that tule elk behaved as central place foragers around water sources during the dry season, and that this behavior was likely tied to forage moisture content. During the wet season, elk appeared to be water independent and selected for high quality forage sources. These patterns were mediated by drought, as severe drought resulted in elk selecting for areas closer to water sources in the dry season and further from water sources in the wet season. My findings will help inform management decisions regarding artificial water source allocation and minimizing the effect of human disturbance on resource availability