The Rashba Hamiltonian and electron transport

The Rashba Hamiltonian describes the splitting of the conduction band as a result of spin-orbit coupling in the presence of an external field and is commonly used to model the electronic structure of confined narrow-gap semiconductors. Due to the mixing of spin states some care has to be exercised in the calculation of transport properties. We derive the velocity operator for the Rashba-split conduction band and demonstrate that the transmission of an interface between a ferromagnet and a Rashba-split semiconductor does not depend on the magnetization direction, in contrast with previous assertions in the literature.Comment: one tex file, two figures; paper to appear in this form in PRB (RC

Mean value coordinates–based caricature and expression synthesis

We present a novel method for caricature synthesis based on mean value coordinates (MVC). Our method can be applied to any single frontal face image to learn a specified caricature face pair for frontal and 3D caricature synthesis. This technique only requires one or a small number of exemplar pairs and a natural frontal face image training set, while the system can transfer the style of the exemplar pair across individuals. Further exaggeration can be fulfilled in a controllable way. Our method is further applied to facial expression transfer, interpolation, and exaggeration, which are applications of expression editing. Additionally, we have extended our approach to 3D caricature synthesis based on the 3D version of MVC. With experiments we demonstrate that the transferred expressions are credible and the resulting caricatures can be characterized and recognized

Metal-Free Nitrogen-Doped Carbon Foam Electrocatalysts for the Oxygen Reduction Reaction in Acid Solution

Metal-free, nitrogen-doped carbon foam is utilized as a model non-precious electrocatalyst system to investigate the role of nitrogen in the oxygen reduction reaction (ORR) in the absence of iron contamination. This graphene-like foam displays relatively high activity for the ORR in acid, despite being proven free from transition-metal impurities. The onset potential is 0.85 VRHE, the mass activity is 2.8 A/g at 0.6 VRHE, and the current density is −4.0 mA/cm2. The maximum electron transfer number is calculated to be 3.6, revealing that a 4-electron pathway is possible in nitrogen-doped carbon, even in the absence of transition-metal coordination sites. The excellent electrochemical activity is attributed to the large surface area (700 m2/g), improved conductivity after graphitization, and the relatively high proportion of tertiary (graphite-like) nitrogen

Classifying program changes during software development

Call number: LD2668 .T4 CMSC 1988 H78Master of ScienceComputing and Information Science

Nonlinear vibrations of a clamped orthotropic circular plate with a concentric rigid mass

Call number: LD2668 .T4 ME 1988 L8Master of ScienceMechanical and Nuclear Engineerin

Electron beam emittance measurement at storage ring with internal target

The method for measurement of electron beam axis position and angular beam spread is developed for a storage ring with internal target. The method is based on the usage of elastic scattering of high energy electrons (positrons) circulating in a storage ring on atomic electrons of the target. If the beam has a finite emittance and the azimuth is taken from the beam axis the distribution of the azimuth angle between Bhabha scattering positron and electron has a width proportional to the beam angular spread and a mean value depending on the magnitude of the displacement of the real storage ring close orbit position from ideal one. Monte-Carlo simulation was made for the positron beam with a real angular dispersion for energy range typical for the electron-proton collider HERA. The consideration can be generalize by taking into account the positron beam and the target polarization and final state radiation. This method can be used also at electron-positron and proton-proton colliders.Развит метод измерения положения оси и углового разброса электронного пучка в накопительном кольце с внутренней газовой мишенью. Метод основан на использовании упругого рассеяния электронов (позитронов) высокой энергии, циркулирующих в накопительном кольце, на атомарных электронах мишени. Если пучок имеет конечный эмиттанс, а азимут отсчитывается от оси пучка, распределение азимутального угла рассеянными позитроном и электроном имеет ширину, пропорциональную угловому разбросу пучка, и среднюю величину, зависящую от величины смещения положения реальной замкнутой орбиты накопительного кольца относительно идеальной. Было выполнено Монте-Карло-моделирование для позитронного пучка с реальным угловым разбросом, типичным для электрон-протонного коллайдера HERA. Проведенное рассмотрение может быть распространено на случай поляризованной мишени и поляризованного позитронного пучка. Этот метод также может быть использован на электрон-позитронных и протон-протонных коллайдерах.Розвинуто метод вимірювання положення осі та кутового розкиду електронного пучка в накопичувальному кільці з внутрішньою газовою мішенню. Метод заснований на використанні пружного розсіяння електронів (позитронів) високої енергії, що циркулюють у накопичувальному кільці, на атомарних електронах мішені. Якщо пучок має кінцевий емітанс, а азимут відраховується від осі пучка, розподіл азимутального кута розсіяними позитроном та електроном має ширину, пропорційну кутовому розкиду пучка і середню величину, що залежить від величини зміщення положення реальної замкнутої орбіти накопичувального кільця щодо ідеальної. Було виконано Монте-Карло-моделювання для позитронного пучка з реальним кутовим розкидом, типовим для електрон-протонного колайдера HERA. Проведений розгляд може бути поширений на випадок поляризованої мішені і поляризованого позитронного пучка. Цей метод також може бути використаний на електрон-позитронних і протон-протонних колайдерах

Huntington’s Disease protein huntingtin associates with its own mRNA

Background: The Huntington's disease (HD) protein huntingtin (Htt) plays a role in multiple cellular pathways. Deregulation of one or more of these pathways by the mutant Htt protein has been suggested to contribute to the disease pathogenesis. Our recent discovery-based proteomics studies have uncovered RNA binding proteins and translation factors associated with the endogenous Htt protein purified from mouse brains, suggesting a potential new role for Htt in RNA transport and translation. Objective: To investigate how Htt might affect RNA metabolism we set out to purify and analyze RNA associated with Htt. Methods: RNA was extracted from immunopurified Htt-containing protein complexes and analyzed by microarrays and RNA-Seq. Results: Surprisingly, the most enriched mRNA that co-purified with Htt was Htt mRNA itself. The association of Htt protein and Htt mRNA was detected independent of intact ribosomes suggesting that it is not an RNA undergoing translation. Furthermore, we identified the recently reported mis-spliced Htt mRNA encoding a truncated protein comprised of exon 1 and a portion of the downstream intron in the immunoprecipitates containing mutant Htt protein. We show that Htt protein co-localizes with Htt mRNA and that wild-type Htt reduces expression of a reporter construct harboring the Htt 3' UTR. Conclusions: HD protein is found in a complex with its own mRNA and RNA binding proteins and translation factors. Htt may be involved in modulating its expression through post-transcriptional pathways. It is possible that Htt shares mechanistic properties similar to RNA binding proteins such as TDP-43 and FUS implicated in other neurodegenerative diseases

Gait-based gender classification using persistent homology

In this paper, a topological approach for gait-based gender recognition is presented. First, a stack of human silhouettes, extracted by background subtraction and thresholding, were glued through their gravity centers, forming a 3D digital image I. Second, different filters (i.e. particular orders of the simplices) are applied on ∂ K(I) (a simplicial complex obtained from I) which capture relations among the parts of the human body when walking. Finally, a topological signature is extracted from the persistence diagram according to each filter. The measure cosine is used to give a similarity value between topological signatures. The novelty of the paper is a notion of robustness of the provided method (which is also valid for gait recognition). Three experiments are performed using all human-camera view angles provided in CASIA-B database. The first one evaluates the named topological signature obtaining 98.3% (lateral view) of correct classification rates, for gender identification. The second one shows results for different human-camera distances according to training and test (i.e. training with a human-camera distance and test with a different one). The third one shows that upper body is more discriminative than lower body