Isolating the chiral magnetic effect from backgrounds by pair invariant mass

Topological gluon configurations in quantum chromodynamics induce quark chirality imbalance in local domains, which can result in the chiral magnetic effect (CME)--an electric charge separation along a strong magnetic field. Experimental searches for the CME in relativistic heavy ion collisions via the charge-dependent azimuthal correlator ($\Delta\gamma$) suffer from large backgrounds arising from particle correlations (e.g. due to resonance decays) coupled with the elliptic anisotropy. We propose differential measurements of the $\Delta\gamma$ as a function of the pair invariant mass ($m_{\rm inv}$), by restricting to high $m_{\rm inv}$ thus relatively background free, and by studying the $m_{\rm inv}$ dependence to separate the possible CME signal from backgrounds. We demonstrate by model studies the feasibility and effectiveness of such measurements for the CME search.Comment: 16 preprint pages 5 figures. v2: added a test with a broad "instanton/sphaleron" peak, and added clarifying texts; v3: added event-shape engineering (and two new figures) and expanded discussions on the low invariant mass region; v4: repeated cautionary discussions in introduction and conclusion sections, published versio

Distributed Voltage Control in Distribution Networks with Electric Vehicle Charging Stations and Photovoltaic Generators

The developments of distributed generators (DGs) and electric vehicles (EVs) are dramatical due to the rapid increase of friendly environment desire. While on another hand, the proliferation of distributed generators (DGs) and electric vehicle charging stations (EVCSs) has brought voltage regulation challenges to distribution systems due to their high generations and heavy loads. In this thesis, a distributed control strategy is proposed which mainly consisted by a reactive compensation algorithm to dispatch surplus reactive power from DGs and EVCSs for proper voltage regulation without violating their converters’ capacity limits or stressing conventional voltage control devices, i.e., on-load tap changers (OLTCs), and an active power curtailment algorithm for DGs to properly integrate OLTC in voltage regulation when the reactive power compensation is deficient. The proposed control algorithms rely on consensus theory and sensitivity analysis, thus, minimizing the active and reactive powers needed for voltage support, and decreasing the net cost of voltage regulation. In the proposed control strategy, three distributed voltage regulation algorithms, as well as a distributed control method for OLTC, are developed and coordinated to realize adequate voltage maintaining effects. Simulation results of a typical distribution system confirm the effectiveness and robustness of the proposed distributed control strategy in continuously maintaining proper voltage regulation for the whole distribution system with minimum power demands from DGs and EVCSs, and reduced tap operation for OLTC, within every 24 hours

High-throughput single molecule screening and selective single molecule PCR for early stage disease diagnosis based on capillary electrophoresis

The purpose of this research was to develop high throughput approaches for single molecule and single cell screening for early stage disease diagnosis. High sensitivity as well as high selectivity is essential for the success screening.;We first demonstrated a laser-induced fluorescence imaging method that allows screening many single molecules at a time based on their electrophoretic mobilities. YoYo-I labeled DNA molecules were tracked by a charge-coupled device (CCD) camera under a microscope while migrating in the electric field. The purpose is not to separate the DNA molecules but to identify each one on the basis of the measured electrophoretic mobility. Each measurement only requires a few milliseconds to complete, which opens up the possibility of screening tens of thousands of molecules every second. The results correlate well with normal capillary electrophoresis (CE) experiments for the same samples under identical separation conditions.;We also developed on-line capillary polymerase chain reaction (PCR) coupled with laser-induced fluorescence detection for individual DNA molecules. A single 30-mum-i.d. fused-silica capillary was used both as the reaction vessel and for isolating single molecules. Because of the small inside diameter of the capillary, PCR-amplified DNA fragments from single molecules were localized in the capillary, providing discrete product zones with concentrations at readily detectable levels. By counting the number of peaks in the capillary via electromigration past a detection window, the number of starting DNA molecules could be determined. Amplification of the 110-bp fragment from an individual human beta-globin gene and the 142-bp fragment from an individual HIV-1 DNA was demonstrated.;Finally, we achieved the direct online capillary PCR amplification from crude biological samples. Human beta-actin gene within individual lymphoblast cells was successfully amplified and detected in the capillary with no extra sample preparation step. This would provide highly selective and sensitive disease diagnosis at a very early stage when there are only a few infected cells. The problem reduces to identifying the suitable primer pairs for each disease marker. The feasibility for continuous-flow PCR monitoring, along with the well-developed capillary array electrophoresis techniques, will provide the high throughput and high sensitivity for large-scale clinical diagnosis

Slacktivists or Activists?: Identity Work in the Virtual Disability March

Protests are important social forms of activism, but can be inaccessible to people with disabilities. Online activism, like the 2017 Disability March, has provided alternative venues for involvement in accessible protesting and social movements. In this study, we use identity theory as a lens to understand why and how disabled activists engaged in an online movement, and its impact on their self-concepts. We interviewed 18 disabled activists about their experiences with online protesting during the Disability March. Respondents' identities (as both disabled individuals and as activists) led them to organize or join the March, evolved alongside the group's actions, and were reprioritized or strained as a result of their involvement. Our findings describe the values and limitations of this activism to our respondents, highlight the tensions they perceived about their activist identities, and present opportunities to support further accessibility and identity changes by integrating technology into their activist experiences