A New Method to Describe Image Theory for an Imperfect Conductor

Problem statement: Modify the equations associated with image theory in order to account for perfect and imperfect conductors. Approach: A novel approach for describing the application of image theory for an imperfect conductive surface was presented. The method presented here purposely downplays the physics of how image theory was employed to account for a charge which is in the presence of an imperfect conductive surface. In turn, it adopted an approach which focused on the geometry that existed between the charged particle and surface ground. In doing so, the proposed method formulated a solution that had minimized the complexity of the original problem while providing an approximation founded upon a geometric relationship. Results: The equations derived had elicited the concept of using plane geometry to augment image theory. Conclusion: A method for evaluating image theory for the imperfect conductor had been presented. As the results had shown, the equations derived had provided an augmented approach to account for surfaces which were both perfect and imperfect

The Horizontal Electric Field Induced by a Lightning Return Stroke

Problem statement: Develop a new formula which describes the horizontal electric field induced by a lightning return stroke in contact with an imperfect conductive surface. Approach: A new method for describing the horizontal electric field induced by a lightning return stroke will be presented. The method presented here had utilized an approach which purposely downplayed the physics of how image theory was employed in the presence of an imperfect conductive surface. It did so by adopting a technique which had focused on the geometry that existed between the lightning channel and surface ground. In doing so, new expressions for surface currents had been derived. This study presented the derivation of these currents along with the horizontal electric field which transpired as a result of their usage. Results: The equation derived had elicited the concept that the channel\u27s image varies with surface conductivity. Conclusion: A method for deriving the horizontal electric field induced by a lightning return stroke had been presented. As the results had shown, once the surface conductivity began to decrease, the horizontal electric field played an increasingly more significant role

The Magnetic Field Induced by a Lightning Strikes Indirect Effect Double Exponential Current Waveform

Problem statement: Develop a new formula which describes the magnetic field induced by a lightning strike\u27s indirect effect double exponential current waveform. Approach: A novel approach for developing a closed-form solution for the magnetic field from the indirect effect double exponential current waveform will be presented. In the literature, models typically employ the pulse waveform to derive the corresponding electromagnetic fields. However, given the Department of Defense (DoD) has incorporated the double exponential current waveform as part of their Electromagnetic Environmental Effects Requirements For Systems , we felt it important to develop a solution for the magnetic field which utilized this waveform. In order to facilitate the integration required for deriving the field, Taylor series expansion was used for all variable dependent exponential terms. In many publications, the dipole and monopole techniques have been used when solving for the magnetic field. However, for this study the dipole technique was deemed the preferred method for evaluating the field. A derivation of the magnetic field will be presented along with a graphical illustration of the field\u27s distribution over time. Results: The equation presented utilized Taylor series to augment the integration required to solve for the magnetic field. Conclusion: A new method for deriving the magnetic field induced by a lightning strike\u27s indirect effect double exponential has been presented. By approximating the variable dependent exponential terms, we were able to minimize the complexity of the mathematics required to solve for the magnetic field in closed-form

Differences in Relationship and Sexual Satisfaction and Social Support Between Only Lesbian, Mostly Lesbian, and Bisexual Women

Research suggests relationship and sexual satisfaction and social support are correlated with components of well-being such as anxiety, depression, and physical health. Differences in relationship and sexual satisfaction and social support have been identified between sexual minority women (SMW; i.e., lesbian and bisexual) and heterosexual women. However, classifying SMW into a single group may mask important differences. Further research is needed to better understand the differences in relationship and sexual satisfaction and social support between subgroups of SMW. Thus, the purpose of the present study was to examine differences in these constructs between women who identify as only lesbian, mostly lesbian, and bisexual. Participants were 427 partnered sexual minority women (Mage = 24.66; 84.8% White; 46.8% only lesbian; 34.2% mostly lesbian; 19% bisexual) recruited from social media to complete an online survey consisting of measures of relationship, health, and related factors as part of a larger study. A one-way ANOVA revealed statistically significant differences between only lesbian, mostly lesbian, and bisexual women in relationship satisfaction (p=.021), sexual satisfaction (p=.049), and social support (p=.034). Post-hoc pairwise comparisons revealed women who identified as only lesbian reported better relationship satisfaction (p=.007), sexual satisfaction (p=.015), and social support (p=.010) than women who identified as mostly lesbian. There were no differences between bisexual women and women who identified as either only lesbian or mostly lesbian. These findings identified important differences between subgroups of SMW, with women who identify as mostly lesbian reporting the lowest relationship and sexual satisfaction and social support. This study provides further evidence that collapsing across identities within the broad category of SMW may mask meaningful subgroup differences. Additional research is needed to further explore disparities in well-being among subsections of SMW. Findings may help identify important protective factors for mental and physical health and well-being specific to SMW of different identities.https://digitalcommons.odu.edu/gradposters2023_sciences/1007/thumbnail.jp

How Lightning Tortuosity Affects the Electromagnetic Fields by Augmenting Their Effective Distance

A novel approach for developing the electromagnetic fields from a lightning return stroke which follows a tortuous path will be presented. The proposed model is unique in that it recognizes that the symmetrical tortuosity of lightning directly impacts the observable distance r, which in turn, alters the resulting electromagnetic fields. In the literature, lightning return stroke models typically employ the assumption that the cloud-to-ground path is straight. Although this assumption yields fairly consistent results across an array of varying approaches, it does not account for lightning\u27s natural physical appearance. Furthermore, straight-line models only account for the cloud-to-ground discharges and do not address branching and/or cloud-to-cloud discharges which are far more common. In reality, the steps which make up the lightning channel\u27s initial descent are staggered or tortuous with respect to each other. Given this fact, the upward traveling current wavefront which follows this prescribed path will exhibit the same characteristics. In doing so, each current segment, which forms along its respective step, induces electromagnetic fields with angular aggregates that propagate outward from their origin. This, in turn, will generate spatial points where there are fields of higher and lower intensities. The results presented in this paper will show how the effective observable distance due to symmetrical tortuosity alters the resulting electromagnetic fields. Furthermore, it will be shown that as the observable distance r is increased, results from the proposed model closely resemble the straight-line model which strongly suggests that symmetrical tortuosity is only influential at relatively close distances

Effect of EMIC waves on relativistic and ultrarelativistic electron populations: Ground-based and Van Allen Probes observations

Abstract We study the effect of electromagnetic ion cyclotron (EMIC) waves on the loss and pitch angle scattering of relativistic and ultrarelativistic electrons during the recovery phase of a moderate geomagnetic storm on 11 October 2012. The EMIC wave activity was observed in situ on the Van Allen Probes and conjugately on the ground across the Canadian Array for Real-time Investigations of Magnetic Activity throughout an extended 18 h interval. However, neither enhanced precipitation of \u3e0.7 MeV electrons nor reductions in Van Allen Probe 90° pitch angle ultrarelativistic electron flux were observed. Computed radiation belt electron pitch angle diffusion rates demonstrate that rapid pitch angle diffusion is confined to low pitch angles and cannot reach 90°. For the first time, from both observational and modeling perspectives, we show evidence of EMIC waves triggering ultrarelativistic (~2-8 MeV) electron loss but which is confined to pitch angles below around 45° and not affecting the core distribution. Key Points EMIC wave activity is not associated with precipitation of MeV electrons EMIC waves do not deplete the ultra-relativistic belt down to 90° EMIC waves cause loss of low pitch angle electrons with energies ~2-8 MeV

Evolutionary divergence of gene and protein expression in the brains of humans and chimpanzees

Although transcriptomic profiling has become the standard approach for exploring molecular differences in the primate brain, very little is known about how the expression levels of gene transcripts relate to downstream protein abundance. Moreover, it is unknown whether the relationship changes depending on the brain region or species under investigation. We performed high-throughput transcriptomic (RNA-Seq) and proteomic (liquid chromatography coupled with tandem mass spectrometry) analyses on two regions of the human and chimpanzee brain: The anterior cingulate cortex and caudate nucleus. In both brain regions, we found a lower correlation between mRNA and protein expression levels in humans and chimpanzees than has been reported for other tissues and cell types, suggesting that the brain may engage extensive tissue-specific regulation affecting protein abundance. In both species, only a few categories of biological function exhibited strong correlations between mRNA and protein expression levels. These categories included oxidative metabolism and protein synthesis and modification, indicating that the expression levels of mRNA transcripts supporting these biological functions are more predictive of protein expression compared with other functional categories. More generally, however, the two measures of molecular expression provided strikingly divergent perspectives into differential expression between human and chimpanzee brains: mRNA comparisons revealed significant differences in neuronal communication, ion transport, and regulatory processes, whereas protein comparisons indicated differences in perception and cognition, metabolic processes, and organization of the cytoskeleton. Our results highlight the importance of examining protein expression in evolutionary analyses and call for a more thorough understanding of tissue-specific protein expression levels

A density-temperature description of the outer electron radiation belt during geomagnetic storms

Bi-Maxwellian fits are made to energetic-electron flux measurements from seven satellites in geosynchronous orbit, yielding a number density (n) and temperature (T) description of the outer electron radiation belt. For 54.5 spacecraft years of measurements the median value of n is 3.7 × 10−4 cm−3, and the median value of T is 148 keV. General statistical properties of n, T, and the 1.1–1.5 MeV flux F are investigated, including local-time and solar-cycle dependencies. Using superposed-epoch analysis where the zero epoch is convection onset, the evolution of the outer electron radiation belt through high-speed-stream-driven storms is investigated. The number-density decay during the calm before the storm, relativistic-electron dropouts and recoveries, and the heating of the outer electron radiation belt during storms are analyzed. Using four different “triggers” (sudden storm commencement (SSC), southward interplanetary magnetic field (IMF) portions of coronal mass ejection (CME) sheaths, southward-IMF portions of magnetic clouds, and minimum Dst) a selection of CME-driven storms are analyzed with superposed-epoch techniques. For CME-driven storms, only a very modest density decay prior to storm onset is found. In addition, the compression of the outer electron radiation belt at the time of SSC is analyzed, the number-density increase and temperature decrease during storm main phase are characterized, and the increase in density and temperature during storm recovery phase is determined. During the different phases of storms, changes in the flux are sometimes in response to changes in the temperature, sometimes to changes in the number density, and sometimes to changes in both. Differences are found between the density-temperature and flux descriptions, and it is concluded that more information is available using the density-temperature description

Ice core evidence for significant 100-year regional warming on the Antarctic Peninsula

We present a new 150-year, high-resolution, stable isotope record (delta O-18) from the Gomez ice core, drilled on the data sparse south western Antarctic Peninsula, revealing a similar to 2.7 degrees C rise in surface temperatures since the 1950s. The record is highly correlated with satellite-derived temperature reconstructions and instrumental records from Faraday station on the north west coast, thus making it a robust proxy for local and regional temperatures since the 1850s. We conclude that the exceptional 50-year warming, previously only observed in the northern Peninsula, is not just a local phenomena but part of a statistically significant 100-year regional warming trend that began around 1900. A suite of coupled climate models are employed to demonstrate that the 50 and 100 year temperature trends are outside of the expected range of variability from pre-industrial control runs, indicating that the warming is likely the result of external climate forcing. Citation: Thomas, E. R., P. F. Dennis, T. J. Bracegirdle, and C. Franzke (2009), Ice core evidence for significant 100-year regional warming on the Antarctic Peninsula, Geophys. Res. Lett., 36, L20704, doi: 10.1029/2009GL040104