Electromagnetic fields in ultra-peripheral relativistic heavy-ion collisions

Ultra-peripheral heavy-ion collisions (UPC) provide unique opportunities to study processes under strong electromagnetic fields. Highly-charged moving ions carry strong electromagnetic fields that act as fields of photons. The exchange of photons could induce photonuclear and two-photon interactions as well as excite the ions into giant dipole resonances (GDRs) or even higher excitation. The GDRs typically decay by emitting photons and even a single neutron, while high-excited resonances usually decay by emitting two or more photons and/or neutrons. On the other hand, the electromagnetic fields of heavy ions are very strong, so one of the two colliding ions is enforced by the other's electromagnetic field. As a result, the two colliding ions are pushed into opposite directions by the electromagnetic forces, and thus the neutrons emitted from different ions could present a back-to-back correlation. Using a Monte-Carlo simulation implementing the electromagnetic fields as well as the neutron emission from previous measurements or model calculations, we qualitatively demonstrate that the above electromagnetic effect is large enough to be observed in UPC, which would provide a clear means to study the strong electromagnetic fields and its effects.Comment: 4 pages, 3 figure

Influence on intraocular pressure of the postural change and daily activities in the early morning in suspected glaucoma patients

AIM:To evaluate the influence on intraocular pressure(IOP)of the postural change and daily activities in the early morning in suspected glaucoma patients.<p>METHODS:The supine and sitting IOP were measured and analyzed on 51 suspected glaucoma patients(100 eyes)with Icare rebound tonometer before and after getting up and daily activities in the early morning. <p>RESULTS: The mean of sitting IOP of 51 patients was 17.12±4.53mmHg, which was significantly lower than the mean of supine IOP(19.14±5.51mmHg). The mean of IOP before and after daily activity of 51 patients were 17.12±4.53mmHg and 14.44±3.90mmHg respectively, which showed significantly difference. <p>CONCLUSION:Postural change and daily activities can result in significant changes of IOP in suspected glaucoma patients

Divergence in Eco-Physiological Responses to Drought Mirrors the Distinct Distribution of Chamerion angustifolium Cytotypes in the Himalaya–Hengduan Mountains Region

Polyploid species generally occupy harsher habitats (characterized by cold, drought and/or high altitude) than diploids, but the converse was observed for Chamerion angustifolium, in which diploid plants generally inhabit higher altitudes than their polyploid derivatives. Plants at high altitudes may experience cold-induced water stress, and we therefore examined the physiological responses of diploid and hexaploid C. angustifolium to water stress to better understand the ecological differentiation of plants with different ploidy levels. We conducted a common garden experiment by subjecting seedlings of different ploidy levels to low, moderate and severe water stress. Fourteen indicators of physiological fitness were measured, and the anatomical characteristics of the leaves of each cytotype were determined. Both cytotypes were influenced by drought, and diploids exhibited higher fitness in terms of constant root:shoot ratio (R:S ratio) and maximum quantum yield of PSⅡ (Fv/Fm), less reduced maximal photosynthetic rate (Amax), transpiration rate (E), intercellular CO2 concentration (Ci) and stomatal conductance (gs), and higher long-term water use efficiency (WUEL) under severe water stress than did hexaploids. Analysis of leaf anatomy revealed morphological adjustments for tolerating water deficiency in diploids, in the form of closely packed mesophyll cells and small conduits in the midvein. Our results indicate that diploid C. angustifolium is more tolerant of drought than hexaploid plants, ensuring the successful survival of the diploid at high altitudes. This eco-physiological divergence may facilitate the species with different cytotypes to colonize new and large geographic ranges with heterogeneous environmental conditions

Factors Influencing the Perception of Seller Credibility in Online Reputation System: an Eye-Movement Approach

The current online reputation systems for online sellers face great challenges from bad-faith behavior such as malicious negative reviews, click farming, mismatch between images and commodities, and forged commodities. To optimize the design of online reputation systems, explore the consumer utilization of credit clues, and describe the law of mutual trust, this paper puts forth three hypotheses about the influencing factors of consumer perception of online seller credibility and integrates various research methods such as an eye-movement experiment, questionnaire survey, econometric analysis, and empirical research. To evaluate the three hypotheses, the display modes of commodities on a current e-commerce platform were optimized, and eye-movement experiments were conducted on original and optimized webpages. Results show that the display of sales growth, the refinement and tagging of review content significantly impacted consumer perception of seller credibility. Further, designers of online reputation systems were advised to display sales trends, provide personalized sales queries, and tag a variety of reviews for consumers to easily ascertain credible sellers. This advice helped curb bad-faith behavior