189 research outputs found
Calculation of the transient response of lossless transmission lines
No full textWe present an analytical calculation of the transient response of ideal (i.e. lossless) transmission lines.
The calculation presented considers a length of transmission line connected to a signal generator with output
impedance Zg and terminated with a load impedance ZL. The approach taken is to analyze a circuit model
of the system in the complex-frequency or s-domain and then apply an inverse Laplace transform to recover
the time-domain response. We consider both rectangular pulses and voltage steps (i.e. the Heaviside function)
applied to the input of the transmission line. Initially, we assume that Zg and ZL are purely real/resistive. At
the end of the paper, we demonstrate how the calculations can be generalized to consider reactive impedances.Science, Irving K. Barber Faculty of (Okanagan)Computer Science, Mathematics, Physics and Statistics, Department of (Okanagan)UnreviewedFacultyUndergraduat
Circuits designed to evaluate the cosine and sine functions on the interval −π to π
No full textWe present a pair of simple analog circuits designed to evaluate the cosine and sine of an input voltage that
varies between −π and +π V. The circuit designs are based off of the Taylor series expansions of cos x and
sin x about x = 0 (i.e. Maclaurin series expansions). For cos x and sin x, the series are truncated after the x6
and x5 terms, respectively. The coefficients of the various powers of x in the truncated series are fine tuned
in order to give the best possible approximations to the trigonometric functions. The circuits are implemented
using low-cost analog multiplier and operational amplifier integrated circuits.Science, Irving K. Barber Faculty of (Okanagan)Computer Science, Mathematics, Physics and Statistics, Department of (Okanagan)UnreviewedFacult
Construction and evaluation of an ultrahigh-vacuum-compatible sputter deposition source
No full textA sputter deposition source for the use in ultrahigh vacuum (UHV) is described, and some properties of the source are analyzed. The operating principle is based on the design developed by Mayr et al. [Rev. Sci. Instrum. 84, 094103 (2013)], where electrons emitted from a filament ionize argon gas and the Ar+ ions are accelerated to the target. In contrast to the original design, two grids are used to direct a large fraction of the Ar+ ions to the target, and the source has a housing cooled by liquid nitrogen to reduce contaminations. The source has been used for the deposition of zirconium, a material that is difficult to evaporate in standard UHV evaporators. At an Ar pressure of 9×10-6 mbar in the UHV chamber and moderate emission current, a highly reproducible deposition rate of ≈1 ML in 250 s was achieved at the substrate (at a distance of ≈50 mm from the target). Higher deposition rates are easily possible. X-ray photoelectron spectroscopy shows a high purity of the deposited films. Depending on the grid voltages, the substrate gets mildly sputtered by Ar+ ions; in addition, the substrate is also reached by electrons from the negatively biased sputter target. © 2017 Author(s)1
Replication Data for: Analyzing the Rhetoric of Supreme Court Confirmation Hearings
No full textThe below data and code replicates the main and appendix materials for "Analyzing the Rhetorical Behaviors of Supreme Court Confirmation Hearings." An important note for these materials: The author's preference for software packages and programming languages to complete different layers of the research design constitutes the incorporation of Microsoft Excel (data collection), STATA (data analysis), and Python (sentiment classification). All replication materials (including STATA do-files and .py files are included below). The author is happy to discuss any data limitations, as well as the procedure for classifying rhetoric using supervised machine learning processes like the one incorporated in this work (Naive Bayes).
Motivation(s): Analyses of Supreme Court confirmation hearings routinely contend with hostility and political overtones becoming ingrained in the process. Accounts from political scientists, normative observers, and participants in these hearings themselves, often point to distinctive moments in the recent history of these hearings as the source of these developments. Chief among them is the contention that the rejection of Robert Bork in 1987 instigated a decades-long collection of grievances that plagued every subsequent hearing. Some observers have continued to support this framing by asserting that even more recent events like the infamous Thomas and Kavanaugh hearings, as well as the Republican Senate's refusal to grant Merrick Garland a hearing, built-from and expand-upon the grievances emanating from Bork. However, more recent literature exploring the contextual substance of interactions between committee members and nominees have questioned these contentions in favor of viewing rhetorical behaviors as a reflection of party dynamics and the balance of interbranch political power.
Approach: I apply supervised machine learning using Naive Bayes to analyze the rhetorical behaviors of committee members during hearings spanning 1970 to 2020.
Findings: My results ultimately suggest two core empirical findings. First, I find little evidence to support the contention that certain key events, Bork or otherwise, significantly impacted rhetorical behaviors. Any layer of analysis, regardless of how many of these aforementioned events are included in the research design, fails to discern any definitive moment where these events might explain longitudinal variation. Second, while the notion that grievances emanating from key events is the primary culprit fails to provide intuitive answers, I do find support for a conjoined influence of strategic party goals and the balance of interbranch political power. That is, rhetorical behaviors are often the result a committee member's position as an in (i.e., sharing the president's political party) or out-party member, as well as whether the hearing exists in unified (i.e., the Senate majority shares the party of the appointing president) or divided government. I find that the behaviors of in-party members alters significantly when they are in the minority. Under these circumstances, they become increasingly more probable to incorporate negative rhetoric, likely as a reflection of the out-party's position as the Senate majority now bearing the weight of real obstructionist consequences. I conclude this work by noting how these conditions and behaviors can produce negative consequences for the Court's institutional support
Poiesis and Obstruction in Art Practice
No full textThis PhD thesis examines the concept of poiesis, that is ‘calling into existence that which was not there before’, in the context of obstruction in studio practice. It poses the question ‘Is there a methodology that engages with obstruction which in turn calls new work’? In this thesis, the concept of poiesis emerging from the late Dr. Murray Cox’s ‘Aeolian Mode’, is analyzed alongside a concept of praxis, (a philosophical companion to poiesis), familiar to artistic practice. This thesis describes the orientation of the original idea, The Aeolian Mode, clinically developed by Dr. Murray Cox in Broadmoor Psychiatric Hospital. This PhD seeks to identify if there are similar ‘tenets of approach’ held within the methodology of ‘The Aeolian Mode’, that would be useful or are identifiable in artistic studio practice. This thesis draws on the work of the philosopher, Professor Richard Kearney, specifically Kearney’s ideas on the necessity of ‘the other’ for ‘radical possibility’ to occur. It maps a context of both Freudian and Jungian interpretations of art practice, identifying how these ideas have shaped the way art is seen today. Furthermore, it challenges the Freudian idea of ‘pathography’ and favours a Jungian approach of ‘individuation’ in the understanding of creative processes. It develops a ‘methodology of the conversation’, interviewing students, established artists, tutors about their approaches to obstruction/poiesis in art practice. Additionally, it examines my own obstruction to painting and identifies the methodology that released me from this obstruction. Conducting these interviews on art practice has enabled me to confirm my initial concerns about Freudian ‘pathography’ whilst validating the possibility of the Jungian concept of ‘individuation’ being of use to art practice. Finally, this PhD discusses the implications for further study and research, which have emerged during the ‘methodology of the conversation’ and the task of dissolving my obstruction to painting
Sap1 dependent replication fork barriers guide integration of LTR retrotransposons in S. pombe
No full textLong Terminal Repeat retrotransposable elements (LTR-TEs) are a large group of eukaryotic Transposable Elements characterized by flanking repeats in tandem orientation - the LTRs. The LTRs of these elements contain sequences that recruit proteins involved in their expression, replication, silencing, organization, and stability. A successful transposable element must maximize its reproductive amplification without jeopardizing its host, and several characterized LTR-TEs appear to accomplish this through the selection of integration sites away from protein coding sequences. However, despite their high relatedness, a universal mechanism that explains how these parasitic elements avoid coding sequences has not been established. Through sequencing of de novo integration sites of the LTR-TE Tf1 from the fission yeast Schizosaccharomyces pombe, we found a strong integration preference for locations near the binding site of Sap1. Sap1 has been previously shown to be a DNA-binding protein that controls the directionality of DNA replication by causing polar fork arrest. Sap1 mutations that mildly affect binding but strongly affect fork barrier activity decrease Tf1 retrotransposon efficiency ten-fold, indicating that Sap1 replication fork barrier activity is a stronger predictor of Tf1 integration than DNA binding. Further, synthetic Sap1 binding sites placed near DNA origins are only competent at Tf1 recruitment when placed in blocking orientation. Interestingly, the fork arresting activity of an independent factor provided in cis can increase the integration efficiency of a barrier-incompetent Sap1 binding site. Thus, both Sap1 binding and replication fork arrest are necessary for Tf1 integration. Together, these data suggest that Sap1 guides insertion of Tf1 by tethering the intasome and blocking the progression of the replication fork, and that the Tf1 transposon uses features of arrested forks to insert into the host genome. Since fork arrest is detectable in many genomic features that recruit LTR-RT integration, such as type III promoters and heterochromatic sequences, these observations point to a universal mechanism for determination of LTR-TE tropism. The questions surrounding the molecular mechanism of Tf1 transposition led to the examination of the CRISPR/Cas9 system as a tool for tethering Tf1 to stalled forks in vivo. However, the CRISPR/Cas9 toolkit had not been developed for S. pombe. Using a novel processed RNA Pol II promoter and the Hammerhead ribozyme we developed a highly efficient CRISPR/Cas9 expression system, leading to >95% modification efficiencies without selection.Ph.D.Includes bibliographical referencesby Jake Zachary Jacob
Screening Electric Fields using a Tube of Water: The Transition from Conductive to Dielectric Screening
No full textNovel setup for detecting short-range anisotropic corrections to gravity
No full textIn this paper we argue that, even though there are strong theoretical and
empirical reasons to expect a violation of spatial isotropy at short distances,
contemporary setups for probing gravitational interactions at short distances
have not been configured to measure such spatial anisotropies. We propose a
simple modification to the state-of-the-art torsion pendulum design and
numerically demonstrate that it suppresses signals due to the large
spatially-isotropic component of the gravitational force while maintaining a
high sensitivity to short-range spatial anisotropies. We incorporate anisotropy
using both Yukawa-type and power-law-type short-distance corrections to
gravity. The proposed differential torsion pendulum is shown to be capable of
making sensitive measurements of small gravitational anisotropies and the
resulting anisotropic torques are largely independent of the details of the
underlying short-distance modification to gravity. Thus, if there is an
anisotropic modification to gravity, from any theory, in any form of the
modified potential, the proposed setup provides a practical means of detecting
it.Comment: 14 pages, 9 figure
1. Theoretical section of the Bachelor´s thesis: Photography and Typography 2. Practical section of the Bachelor's thesis: Visual author style of a professional photographer
No full textVe své práci jsem chtěla rozebrat "problematiku" použiti fotografií na různých propagačnich materiálech. Jak grafici běžně pracují s fotografií, jake jsou výhody a nevýhody. Můj názor a vlastní zkušenosti s fotografy.In my work I would like to took apart " problemms" using photos in different advertising mediums. How graphic designers usually work with their photos. How advantages and disadvantages they have. My oppinion and my own experience with photographers.Ústav reklamní fotografie a grafik
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