Paradox with Phase-Coupled Interferometers

A pair of interferometers can be coupled by allowing one path from each to overlap such that if the particles meet in this overlap region, they annihilate. It was shown by one of us over thirty years ago that such annihilation-coupled interferometers can exhibit apparently paradoxical behaviour. More recently, Bose et al. and Marletto and Vedral have considered a pair of interferometers that are phase-coupled (where the coupling is through gravitational interaction). In this case one path from each interferometer undergoes a phase-coupling interaction. We show that these phase-coupled interferometers exhibit the same apparent paradox as the annihilation-coupled interferometers, though in a curiously dual manner.Comment: Comments welcom

Secure your own mask first before assisting others: Investigating the health of frontline care workers during the COVID-19 pandemic

COVID-19 pandemic has placed unprecedented pressure on health care workers (HCWs). This pressure is caused by the scarcity and prolonged use of PPE (Hu et al., 2020), being exposed to suffering from their patients (Brooks et al., 2020), making difficult moral decisions (Xiang et al., 2020), constant changes in policies and regulations (Chen et al., 2020), and the fear of death or spreading the infection to their loved ones (Shanafelt et al., 2020). To investigate this issue, 329 HCWs in Nova Scotia were recruited. Participants completed a survey asking about their demographics and pertinent occupational health constructs. The hypotheses were tested using structural equation modelling and regression analysis. Based on the results, pandemic anxiety was associated with emotional exhaustion and cynicism. Moral distress was associated with cynicism. Peer social support was associated with lower cynicism and higher professional efficacy. Organizational support was highly correlated with all three subfactors of burnout. Burnout subfactors alone could predict up to 30% of the variance in turnover intention controlling for the participants’ demographics and work characteristics. The findings did not support the mediation effect of burnout in the relationship between COVID-19 demands/resources and withdrawal behaviour. In conclusion, during large-scale public health events such as the COVID-19 pandemic, boosting peer and organizational support skills can buffer and mitigate the stressors to help people be more engaged with their work and stay longer in their organization

Very Slow Search and Reach: Failure to Maximize Expected Gain in an Eye-Hand Coordination Task

We examined an eye-hand coordination task where optimal visual search and hand movement strategies were inter-related. Observers were asked to find and touch a target among five distractors on a touch screen. Their reward for touching the target was reduced by an amount proportional to how long they took to locate and reach to it. Coordinating the eye and the hand appropriately would markedly reduce the search-reach time. Using statistical decision theory we derived the sequence of interrelated eye and hand movements that would maximize expected gain and we predicted how hand movements should change as the eye gathered further information about target location. We recorded human observers' eye movements and hand movements and compared them with the optimal strategy that would have maximized expected gain. We found that most observers failed to adopt the optimal search-reach strategy. We analyze and describe the strategies they did adopt.Psycholog

Geotechnical performance of group of stone columns

Stone columns are known to be a cost effective and environmental friendly ground improvement technique, which is widely used to enhance the performance of shallow foundations built on soft ground. Stone columns increase bearing capacity, reduce settlement, reduce significantly the consolidation period and minimize the liquefaction potential of the ground. The current design of these columns is generally based on theories developed for single columns, ignoring the group interaction and accordingly the group efficiency. In the literature, reports can be found to confirm that the failure of single stone column is mostly due to bulging, meantime for a group of stone columns, the failure mechanism takes place by massive shear failure of the group and the surrounding soils. The objective of this thesis is to develop a numerical model, based on a two dimensional finite element technique. The model is capable to identify the different mode of failures of single and group of stone columns for a given columns/soil/loading condition. In these cases, group interactions were examined and evaluated. Parametric study was conducted on the parameters believed to govern this behavior. The results produced in this study showed that ground reinforced by group of stone columns may fail by general, local or punching shear failure, depending on geometry of the group and properties of the surrounding soils. Analytical models were developed for the ultimate bearing capacity of single and groups of stone columns. The models take into consideration the column interaction among the group and the strength of the surrounding soils and accordingly depict the appropriate mode of failure. Furthermore, analytical model was developed for the prediction of settlement of foundations under single or widely spaced stone columns. The design theories are provided with design procedures and charts for practical use

Induced Myopia Secondary to Blunt Trauma

A 28-year-old young man presented with sudden and severe visual loss in the left eye, starting three days ago following blunt head trauma from a closed fist. Vision was not improved to better than 0.4 in the left eye. Slit lamp examinations revealed asymmetric anterior chamber depth (ACD) with shallow ACD in the left eye. The key learning in this report is the use of anterior segment optical coherence tomography (AS-OCT) to better document the anterior segment changes following the blunt trauma. AS-OCT was used to visualize the forward displacement of the iris-crystalline lens diaphragm secondary to ciliary body anterior rotation and ciliochoroidal effusion. There was a temporary myopic shift about 7.00D which resolved after 15 days

SETTLEMENT OF A GROUP OF STONE COLUMNS IN SOFT SOIL

A number of theoretical methods have been developed over the years to calculate the amount settlement of the soil reinforced with group of stone columns. The results deduced from these methods sometimes show large disagreement with the experimental observations. The reason of this divergence might be due to the fact that many of the previous methods assumed the deform shape of the columns which is different with the actual case. A new method to calculate settlement of the ground reinforced with group of stone columns is presented in this paper which overcomes the restrictions made by previous theories. This method is based on results deduced from numerical modeling. Results obtained from the model are validated. Key Words: Stone columns, group, settlement, soft soil, prediction, geo-material

3D Printed Models for Teaching Orbital Anatomy, Anomalies and Fractures

Purpose: The aim of this study was to determine the efficacy of using 3D printing models in the learning process of orbital anatomy and pathology by ophthalmology residents. Methods: A quasi-experimental study was performed with 24 residents of ophthalmology at Mashhad University of Medical Sciences. Each stratum was randomized into two groups. The educational booklets were distributed, and various forms of orbital 3D models were printed from orbital computed tomography (CT) scans. Knowledge enhancement on the topics was measured by comparing pretest and posttest scores. Results: Thirteen residents who were trained using traditional methods were deemed the control group; while 11 residents who were trained using the 3D printed models were classed as the intervention group. The control group was younger than the intervention group (P = 0.047). The results showed that there was a statistically significant difference in the total posttest scores between the two groups. Based on the repeated measures of the analysis of variance (ANOVA), score variables were significant between the two groups (P = 0.008). Interestingly, the use of the 3D educational model was more effective and statistically significant with the year one residents as compared to the year two residents (P = 0.002). Conclusion: This study is the first one in Iran quantifying the effects of learning using 3D printed models in medical education. In fact, 3D modeling training is seemingly effective in teaching ophthalmic residents. As residents have never encountered such technology before, their experience using 3D models proved to be satisfactory and had a surprising positive effect on the learning process through visual training

Fabrication of surface-enhanced Raman scattering sensors to detect antibiotic residues in muscle foods using gold nanoparticles

The surface-enhanced Raman scattering (SERS) method is a widely used technique for molecular structure analysis. This method relies on the enhancement of the Raman signal through the use of plasmonic nanostructures, such as gold and silver, which serve as substrate sensors. The use of pre-made sensors can effectively enhance the efficiency and cost-effectiveness of SERS. In this study, we used a fast, simple, and cost-effective method to create a suitable substrate for SERS analysis. Initially, gold colloidal nanoparticles with dimensions ranging from 50 to 80 nm were synthesized and deposited onto glass slides to create a uniform and rough substrate. To stabilize the gold nanoparticles, a sulfur compound called "1-dodecanethiol" was selected, increasing the contact angle of the sample to 45° on the glass slide. Florfenicol, one of the most common antibiotic residues in muscle foods, was selected as an analyte. Spectrum acquisitions at various points on a single slide demonstrated acceptable substrate uniformity (RSD = 8.44%). Further experiments conducted on different slides confirmed the consistency of the results (RSD = 7.90%). Finally, the reliability of the results was confirmed through spectrum acquisitions over various time intervals (RSD = 1.26%)

The Effect of Cycloplegia on the Ocular Biometric and Anterior Segment Parameters: A Cross-Sectional Study

INTRODUCTION: To evaluate the effects of cycloplegia on the biometric components and anterior segment parameters of the eye. METHODS: In this cross-sectional study, changes to axial length (AL), anterior chamber depth (ACD) lens thickness, anterior chamber angle (ACA) and volume, corneal thickness in the pupil center (PC), corneal curvature (CC) and white-to-white (WTW) following cycloplegia induced by tropicamide 1% in 42 eyes of patients aged 23-58 years were assessed. Biometric components and anterior segment parameters were measured using an IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany) and a Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany), respectively. RESULTS: Significant statistical changes in ACD (increased by 0.06 ± 0.05 mm; p  0.05). Also, a significant inferior displacement of the PC along the vertical axes was seen (p = 0.020). CONCLUSION: Cycloplegia resulted in a deeper ACD and thinner lens thickness. These changes should be considered in determining intraocular lens (IOL) power to prevent refractive surprises in cataract surgery and also in the phakic IOL implantation