M. Kim

We numerically determine the cosmological branch of the free function in a nonlocal metric-based modification of gravity which provides a relativistic generalization of Milgrom's Modified Newtonian Dynamics. We are able to reproduce the $\Lambda$CDM expansion history over virtually all of cosmic history, including the era of radiation domination during Big Bang Nucleosynthesis, the era of matter domination during Recombination, and most of the era of vacuum energy domination. The very late period of $0 \leq z < 0.0880$, during which the model deviates from the $\Lambda$CDM expansion history, is interesting because it causes the current value of the Hubble parameter to be about 4.5\% larger than it would be for the $\Lambda$CDM model. This may resolve the tension between inferences of $H_0$ which are based on data from large redshift and inferences based on Hubble plots.

We wanted to learn if pupillary changes induced by looking and attending to stimuli on the right and left are asymmetrical. In humans, there are hemispheric asymmetries in the control of attention-arousal systems. Because attention and arousal may influence pupil size, asymmetric pupillary responses may be seen when looking and attending in different directions. Twelve right-handed, healthy volunteers served as subjects. Using infrared pupillography, we recorded changes of pupillary diameter while subjects were looking and attending to the stimuli on the right and left sides of space. For the one second following a saccade, there are three phasic pupillary responses, an initial constriction (C1) then a dilation (D1), followed by constriction (C2). Evaluation of these three responses revealed right-left asymmetries with more pupil dilation (D1) when looking to the stimulus on the right. Our results suggest that subjects are more aroused when looking to the right than when looking to the left.

The upgrade of the CMS detector for the high luminosity LHC (HL-LHC) will include gas electron multiplier (GEM) detectors in the end-cap muon spectrometer. Due to the limited supply of large area GEM detectors, the Korean CMS (KCMS) collaboration had formed a consortium with Mecaro Co., Ltd. to serve as a supplier of GEM foils with area of approximately 0.6 m2. The consortium has developed a double-mask etching technique for production of these large-sized GEM foils. This article describes the production, quality control, and quality assessment (QA/QC) procedures and the mass production status for the GEM foils. Validation procedures indicate that the structure of the Korean foils are in the designed range. Detectors employing the Korean foils satisfy the requirements of the HL-LHC in terms of the effective gain, response uniformity, rate capability, discharge probability, and hardness against discharges. No aging phenomena were observed with a charge collection of 82 mC cm−2. Mass production of KCMS GEM foils is currently in progress.

Abstract The Gas Electron Multiplier (GEM) detectors of the GE1/1 station of the CMS experiment have been operated in the CMS magnetic field for the first time on the 7 th of October 2021. During the magnetic field ramps, several discharge phenomena were observed, leading to instability in the GEM High Voltage (HV) power system. In order to reproduce the behavior, it was decided to conduct a dedicated test at the CERN North Area with the Goliath magnet, using four GE1/1 spare chambers. The test consisted in studying the characteristics of discharge events that occurred in different detector configurations and external conditions. Multiple magnetic field ramps were performed in sequence: patterns in the evolution of the discharge rates were observed with these data. The goal of this test is the understanding of the experimental conditions inducing discharges and short circuits in a GEM foil. The results of this test lead to the development of procedure for the optimal operation and performance of GEM detectors in the CMS experiment during the magnet ramps. Another important result is the estimation of the probability of short circuit generation, at 68 % confidence level, p short HV OFF = 0.42 -0.35 +0.94 % with detector HV OFF and p short HV OFF &lt; 0.49% with the HV ON. These numbers are specific for the detectors used during this test, but they provide a first quantitative indication on the phenomenon, and a point of comparison for future studies adopting the same procedure.

Unilateral sensory neglect has been attributed to various defects, including a hemispatial attention-arousal deficit. However, support for this hypothesis has only been indirect. Therefore, the purpose of this study was to further test the hemispatial attentional-arousal hypothesis by measuring pupillary response as an index of arousal.There were two experimental subjects with neglect and six matched controls. Stimuli (Arabic numbers) were presented on the right, left, and centre of a screen. The subjects were asked to look at the number in the centre, on the right, or left of the screen while their pupil diameter was measured.Unlike the control subjects, the subjects with neglect, who were aware of the left sided stimuli, did not show a pupillary dilatation when they looked at the stimulus on the left.Although this study provides support for the hemispatial attention-arousal hypotheses of neglect, it does not preclude the possibility that other mechanisms may also be important.

Implement 2D-3D registration on linacs with electronic portal imaging devices (EPIDs) to yield accuracy similar to 3D-3D registration using linac-based conebeam CT (CBCT) for registrations based on bony anatomy. Our specific methodology overcomes 1) long computation times due to multiple digitally reconstructed radiograph (DRR) generation requirement, and 2) potential positioning errors due to local minima trapping. It offers high precision 3D patient positioning without requiring onboard CBCT on each treatment linac. 2D-3D registration uses multiple 2D projection images to achieve 3D positioning by computing the best alignment based on bony anatomy of the 2D portal images with DRRs at incrementally different poses. Challenge 1) can be overcome with specialized code that assigns DRR generation to the graphics processing unit (GPU) rather than CPU but this requires dedicated software/hardware for each EPID. Challenge 2) can be overcome by requiring human oversight to check the validity of the registration but this limits the automation level needed for large patient throughput. We present a 2D-3D registration methodology that can be implemented either on 1) a single workstation equipped with a NVIDIA GeForce 8800 GPU and a DRR server software, which is networked to multiple standard EPID viewing stations via TCP/IP, hence minimizing hardware requirements, or 2) each viewing workstation containing the GPU and DRR software. A registration quality evaluator (RQE) is used to avoid local optima associated with 2D-3D registrations. RQE is an algorithm based pattern classifier that identifies local optima trapping of an optimization, which can lead to incorrect patient positioning. We implemented a 2D-3D registration using two strategies: 1) GPU on a server and a remote client PC connected through intranet, which achieved an accuracy of 1 mm and 1° for phantom and clinical imaging with computation times <30 sec; 2) both the server and the client in a single workstation, in which computation time <10 sec. The use of RQE eliminated any local optima trapping. RQE training yielded a sensitivity and a specificity of 0.9804 (0.8955–0.9995) and 0.9388 (0.8313–0.9872), respectively, at 95% confidence interval. Using test dataset from phantom imaging, the sensitivity and the specificity of RQE were 0.939 and 0.937, respectively. Currently CBCT generally has insufficient image quality for accurate deformable registration based on soft tissue, and 3D-3D registrations are largely driven by bony anatomy. Our 2D-3D registration provides accuracy comparable to 3D-3D registration using CBCT for registrations based on bony anatomy. The proposed proof-of-concept system offers a simple and inexpensive solution for those radiotherapy patients requiring precise 3D patient positioning based on bony anatomy without invasive fiducial markers that can be implemented on any linac with EPID imaging.